annex a - architectural & services works appendi… · annex a - architectural & services...
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ANNEX A - ARCHITECTURAL & SERVICES WORKS General Notes: The Contractor is required to include in his tender this and all other general specification of works or descriptions as detailed in the Consultant’s drawings and Breakdown Schedule as accepted and expected of them by the respective trades and profession. All other works (including ancillary works) that are required to see to the successful completion of the project to CSC are deemed to be inclusive in the contract as quoted in the tender and contract price. The Contractor is deemed to have inspected the site and documents and is satisfied that the works as described in the tender, documents and contract drawings are sufficient, complete and clear enough for the Contractor to understand and construct the project to completion with CSC. Should the Contractor require any additional items or information, these should be asked or informed before the contract is executed between the Contractor and the Company. Under no circumstances will the Company and or the Consultants entertain any claims for extra time or cost due to plead of ignorance or misunderstood interpretation of the documents and drawings. It is agreed by the Contractor that the Consultants assessment and directions in all matters arising out of such are final and non-negotiable. Should there be a discrepancy, omission, typographical error or duplication of items resulting in a reduction in cost, this cost is allowed by the Contractor to be omitted, deducted or adjusted from the contract sum in the final accounts leading up to the Company’s acceptance of the project. Should there be an addition, discrepancy or typographical error or addition of items resulting in an increase in cost, the Contract sum cannot be adjusted by the Contractor and is treated as absorbed or included in the first instance when the contract is signed. The above is excluding any direction, instructions, or amendments issued by the Company and or the Consultants during the course of the project as determined by the Consultants to be or could be varied. In case of doubt, the Contractor is to seek clarification from the Consultants. This specification may carry some items that is not required in the works as described and should be ignored. Only relevant specification is to be referred to.
I PART 1 - GENERAL PRELIMINARIES A. SITE PROGRAMME The Contractor is to prepare and submit to the Consultant a detailed time schedule he proposes to execute the
whole of the Works and to sign it as part of the contract documents. The Contractor is to allow for providing all necessary additional copies of the agreed schedule.
B. SITE MANAGEMENT The Contractor is to allow in his prices for all on and off site management cost including an air-conditioned site
container office where weekly site meetings can be held. C. LABOUR The Contractor is to allow in his prices for the following items: -
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1) Importation of labour including higher rates of wages, transport, travelling time, fares, subsistence and
lodging allowances. 2) Operation of incentive schemes and costs of overtime working. 3) Guaranteed time. 4) Insurance and pensions. 5) Annual and Public Holidays. 6) Sick pay. 7) Any other disbursements and added requirements to comply with Labour Ministry, Union and other authority
organizations arising from employment of labour. D. SAFETY, HEALTH AND WELFARE The Contractor is to provide suitable safety, health and welfare measures and amenities to comply with the current
Statutory Regulations for the Building Industry. The Contractor shall be responsible for the health and safety of his own and of Sub-Contractor’s personnel and
must ensure that they conduct themselves in a reasonable and safe manner consistent with the prevention of injury to persons or damage to property. The Contractor in this regard must conduct induction classes to all workers entering the Site.
The Contractor must observe all statutory regulations and codes of practice applicable to his and to Sub-
Contractor’s personnel and to the work covered by the contract and must also observe any special safety requirements notified to him by the Consultant.
The Contractor must nominate a member of his staff (Safety Officer) to deal with safety matters and inform the
Employer/Consultant of the name and mobile phone number of his nominee. The Safety Officer must be contactable 24 hours/ 7 days and conduct inspections as required by him under the statutory requirements.
The Employer will inform the Contractor’s Safety Officer of any special safety procedures in force and he will then
be responsible for training all the of the Contractor’s personnel on the procedures. E. USE OF EXISTING TOILETS, WATER & POWER The Contractor will arrange his own temporary toilet facilities for all workers on site to use freely. Temporary
supplies and cleaning of the toilets for cleanliness and health requirements must be arranged and paid for by the Contractor.
The Contractor can separately arrange with the Employer (if allowed) for the use of toilet facilities, water and
electricity power and will be responsible for any damage, cleanliness arising out of such usage. The Employer reserves the right to charge or refuse the use of Employer’s toilets, supply of water and power. F. SECURITY The Contractor’s attention is drawn to the fact that the Employer reserves the right to implement the following
security measures: - a) The Employer reserves the right to search any vehicle, person or property, entering, leaving or present on the
Employer’s premises.
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b) The Contractor shall at the reasonable request of the Employer’s Company Security Officer produce for his immediate inspection a list showing the full names, NRIC No., home addresses, date of birth and occupation of each of his employees working on Company property. The Contractor shall be responsible for ensuring that his Sub-Contractors are aware of and will comply with these requirements. Security passes will be issued and worn at all times on site and within the Airport Restricted Areas. Workers without security passes will not be allowed into the Airport security area.
G. MATERIALS, GOODS AND WORKMANSHIP All materials, goods and workmanship shall be of the best quality of their respective kinds and trade. Consultant’s
assessment of the quality and defect or acceptance will be final. All materials and goods shall be used or fixed strictly in accordance with the manufacturer’s printed instructions and
recommendations. The Contractor is deemed to comply with all good trade and industry practices as published by the BCA under the
CONQUAS 21 series. These booklets are available for purchase from the BCA should it be required by the Contractor and is not reproduced here. Should there be works that are not reflected or specified, the Consultant’s direction, instruction or determination will take precedence and the Contractor must abide by it. The Consultant in his determination of the unspecified works will be fair in his judgment and provide for any variation to time, or cost as deemed fair.
H. PLANT, TOOLS AND VEHICLES Provide all necessary plant, tools and vehicles for the proper execution of the Works in the agreed period of time for
completion of this Contract. The Contractor’s attention is particularly drawn to the prevention of nuisance to the Employer and adjoining owners
and occupiers from the carrying out of the Works as previously described under the item head “Adjoining Property” and “Prevention of Nuisance”.
I. GENERAL SCAFFOLDING, CRANE, LIFTING EQUIPMENT & GONDOLA SYSTEM Provide all necessary general scaffolding, Crane, Lifting Equipment & Gondola for the proper execution of the
Work. Metal scaffolding is preferred to bakau scaffolding, and all such works, including gondola, must be with Contractor’s PE approval and endorsement and approved by the authority for use.
J. SAFEGUARDING THE WORKS Safeguard the Works, materials and plant against damage and theft including all necessary storage, watching and
lighting for the security of the Works. The Employer does not provide any safe storage facility and all stores are to be within the work site without obstructing or inconvenience Employer’s areas or use.
K. MAINTENANCE OF ROADS, ETC. The Contractor is to make good at his own expense any damage to roads, bridges, footpaths, rights-of-way, grass
and landscape etc. (including services, drains and sewers). A pre-condition survey by the Contractor is required to establish existing condition of site and surrounding to avoid claims of damage and responsibility.
L. MAINTENANCE OF SERVICES Protect, uphold and maintain public and private services, drains, Cables and sewers and give all necessary notice
to the local authority, SATS, CAG or other statutory undertakers about the works to be done over, around and under it. The Contractor is responsible to protect (temporarily or permanently), carry out any works required to help maintain such services during and after construction.
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The Contractor is to make good at his own expense any damage to public and private services, drains and sewers caused by the carrying out of the Works provided such damage is due to any negligence, omission or default of the Contractor (or his Sub-Contractor).
M. MAINTENANCE OF EXISTING BUILDING, ETC. Protect and uphold the existing buildings on the site and the adjoining buildings during the period of this Contract. The Contractor is to make good at his own expense any damage to the existing buildings, fences etc on or around
the site and any adjoining buildings/property. N. WATER FOR THE WORKS The Contractor will arrange with the building owners or Employer for the use of the water at site. The location point
of the supply will be as advised. The Contractor is to make all necessary temporary arrangements for the distribution from that point. Charges by the Employer for the use of water may apply.
O. LIGHTING AND POWER FOR THE WORKS Provide lighting and power for the Works and make all temporary arrangements for distribution about the site. A
separate Contractor’s Site Distribution Board (PE Certified) is required to be fitted for this distribution. The Contractor can alternatively arrange with the building owner or Employer for the use of the above. The location
point of the supply will be as advised. Charges by the Employer for the use of electrical services may apply. P. P.C. SUMS If the Contractor is permitted to tender (and his tender is accepted) for any work, materials or goods for which a P.
C. Sums has been included in the document, such P. C. Sum together with profit (if any) which has been added by the Contractor will be omitted. Any profit and attendance (P&A) required by the Contractor shall be included in his tender for the work covered by such P.C. Sums. If none stated, it will be deemed that no P&A cost is charged by the Contractor.
Q. SUB-CONTRACTORS, LOCAL AUTHORITIES, STATUTORY
UNDERTAKERS AND FIRMS EMPLOYED DIRECT It is deemed that the following attendance is required of the Contractor which is deemed inclusive in his tender. a) General Attendance General attendance on nominated sub-contractors, local authorities, statutory undertakers and firms employed
directly shall be deemed to include allowing reasonable and free use of standing scaffolding, rooms, sanitary accommodation and welfare facilities, providing space for office accommodation and for storage of plant and materials, providing light and water for their work and clearing away rubbish.
b) Special Attendance Special attendance on nominated sub-contractors shall be deemed to include unloading and distributing the
sub-contractor’s materials and plant, providing light to the nominated sub-contractor’s office and storage area and providing power for tools, etc.
c) Additional Items for Attendance Additional items for attendance on nominated sub-contractors, where applicable, have been described
separately in this document.
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d) Particulars of Requirements The Contractor is to obtain from sub-contractors, local authorities, statutory undertakers and firms employed
direct full particulars of their requirements with regard to holes, chases, recesses and other details and is to supply them with all necessary dimensions and other information to enable their work to be correctly executed and subsequent alteration obviated.
If the Contractor strikes/remove scaffolding before ascertaining whether it is required by any sub-contractor,
local authority, statutory undertaker or firm employed directly, he will be responsible for re-erecting the scaffolding if so required at his own expense.
e) Damage to Works It is the responsibility of the Contractor that the work of any sub-contractor, local authority or statutory
undertaker employed by him under this Contract is not damaged by another or by himself and will be required to make good any such damage at his own expense and to the satisfaction of the Consultant.
R. PHOTOGRAPHS The Contractor shall not take or permit to take any photographs on site without the written consent of the Employer.
No photographs so taken shall be used for publicity purposes without the written consent of the Employer. Progress photographs before, during and after construction must be provided, if requested. Cost of same is
considered inclusive in the tender. S. TEMPORARY HOARDING, FENCE AND GANTRIES The Contractor is to allow for providing all temporary hoarding, fenced & planked footways, guard rails, gantries and
the like as may be necessary for protecting the public and the adjoining owners/occupiers, for meeting the requirements of any local or other authority and for the proper execution of the works and pay all charges in connection therewith.
Any hoarding erected is to be painted externally with 2 costs of oil paint of a colour approved by the Consultant.
Polykem finish boards are also allowed. No advertisements will be permitted on any hoarding, fan, guard rail, gantry, etc. except safety signs and “We are
moving with you “and “We are Building to serve you better”. These signs will be deemed inclusive. T. NAME BOARD A site notice board is left to the Contractor’s proposal and will follow the BCA’s requirements in size etc as specified
( if stated ) but the letter, details and positions must all be agreed with the Consultant prior to the erection and the Contractor must pay for all costs incurred and deemed inclusive in the tender. SATS Logo/CAG/CAAS logo is to be inclusive.
No other advertisement or trade signs will be permitted on the site unless approved by the Employer/Consultant. U. PROTECTING, DRYING AND CLEANING THE WORKS The Contractor is to maintain, whenever practicable, continuity of working and productivity during inclement
weather. Provide all temporary screening to openings, etc. required for drying and controlling the humidity of the Works in an
efficient manner and at own costs.
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Remove all rubbish and debris, clean the Works internally and externally and hand over the whole of the Works in a clean condition to the approval of the Employer.
V. SUBSTITUTIONS If the Contractor wishes to substitute materials or goods he must obtain the Consultant’s written approval before
proceeding. It is recommended that if the Contractor wishes to make any substitutions, then he should do so when tendering for
the project. Samples, brochures, details, etc., are to be submitted with the tender if the Tenderers are providing an equivalent or
substitute material. W. NOTE REGARDING PROPRIETARY NAMES Whenever a proprietary name is used in any of the Contract Documents it is used to denote the particular standard,
specification, performance, finish and appearance of the product to which it refers and it is deemed to include. Other equal or superior products may be substituted providing they match or improve upon all named products and
are approved by the Designer. Samples, specifications, brochures are to be submitted together with this tender if the Tenderer proposes to do so.
II. PART 2 - MATERIALS AND WORKMANSHIP SPECIFICATIONS This specification is divided into the following sections: - 1.1 PARTITIONS, JOINERY & FURNITURE CONSTRUCTION a) Timber All approved HW (as schedules and samples) carcass timber to be seasoned to within 2% of the relative
humidity of the interior space in which it is being used. No dead knots, cup or stair shakes, or other splits allowed to face timber. No insect infected timber allowed for face or carcass work. Sheet materials - Plywoods, laminated board and chipboard All plywoods to be HW construction with waterproof adhesive bonding. Surface for fairface finishing. All laminated boards to have HW constructional veneers and waterproof adhesive bonding. Surfaces for
fairface finishing. Clipboard shall be of a thickness and density suitable for use for flat panels of domestic furniture (e.g. Wyeroc
600 density or similar approved). Plywood shall be MR bonding grade 2 veneer or of equivalent type and grading. Manufacture must be by the ‘dry cementing’ process. Plywood manufactured by the wet or semi-dry method shall not be used.
Veneers, Laminated Plastics and Mirror. b) Veneers
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All veneers to be selected and approved prior to application. No veneers for face work to be filled or pleated. Clean splits allowed if paper taped prior to application. Surface of the face veneers to be dampened and fine sanded prior to application of finishes. c) Laminated Plastics Plastic laminate shall be 1.5mm, construction in melamine resin/paper ‘furniture grade’. The laminate shall be
uniform in colour and free from cracked edges or damage or imperfection of any kind. Balancing veneers to be applied only to faces, which are to remain permanently concealed may be of a cheaper quality balancer but shall be compatible with the decorative finish, and obtained from the same supplier. Veneers, plastic laminate where specified shall be applied to both faces of panels, glued and pressed to cores to ensure firm and even overall adhesion. Laminate shall be carried over edging, brought flush with face of edging and then finished with slight chamfer. Panels shall be faced on each side with a single sheet of laminate without intermediate joints. Finished faces shall be flat and true, free from warping, waving, high or low spots. Where an entire panel face is to remain concealed, this face shall have a balancing veneer as described previously and applied in the same manner as set out above. The grain shall be straight and matching panels/components must have an equal number of leaves. Each leaf to be of the same width with alternate leaves turned and matched exactly.
Veneers shall be totally bonded to the core material, and care must be taken to ensure that there are no loose
areas or edges. But joints between leaves must not show and the only evidence that a veneered surface consists of more than one leaf shall be the figure and matching of veneers. Veneer joints shall be parallel to the edges of panels/components. All surfaces shall be thoroughly sanded and free from defects of every description including tape, if used for jointing veneers, sanding marks, adhesive, etc. Care must be taken not to sand through the veneer thickness. Edges must be thoroughly sanded and not show machine marks nor other defects and the standard of finish shall be the same as flat surfaces.
All cores to panels/components shall be solid and of the same material throughout which shall be of MDG
chipboard or plywood. Cores shall be in one peace in any one panel. All cores shall be edged all round with hardwood to form exposed profiles of panels.
Tongues between edging and cores may be considered as optional; of the Contractor undertakes to provide
equally storing glued joints. Lipping shall be applied with adhesive not panel pins and sanded flush with core material before veneering.
Exposed corners shall be mitered very precisely. When panels/components are seen in close relationship, the colour and grain characteristics of the veneers
must be consistent. Veneers selected for inside surfaces must not be of an inferior quality. d) Mirror Mirrors are to be 6mm silvered glass cut to size as indicated and polished on all edges unless dimensioned as
thicker on drawings. e) Diamond Mirror 3mm or 4mm selected glass, silvered, coppered and laminated with FR grade foam interlayer to a rigid
aluminium-skinned foam board. f) Storage Store on edge protecting the board’s edge from mechanical damage. The isocyanurate board is supplied
oversized and trimmed off with a knife before installation. This protects the edge of the mirror in transit.
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g) Joints All joints shall be properly made and accurately machined to give a perfect fit without gaps between shoulders
of the joints and abutting surfaces. All joints are to be glued properly under pressure with the best quality glues of the appropriate type. Open joints disguised with filler will not be accepted.
The Contractor shall be responsible for the sound construction of all components using recognized forms of
joints in appropriate positions. This specification and the drawings listed on the drawing schedule do not show all methods.
All mortise and tenon joints to be 1/3 / 1/2 proportion and to have HW fox-tailed wedges, haunched where
necessary. Glue grooved HW dowels with rounded ends to be used. Plywood loose tongues to be in HW laminated construction with waterproof adhesive (not to exceed ½ of the
total interface width). Edge Lippings & Table Tops Edge lippings to be flush with top face surface and have external arises rounded. Corner and inter edge joints
dowelled, with mitres at right-angled junctions. Carcass Work and Shelves Veneers carried over edge lippings (lippings applied and cured prior to veneering) no end grain to be
revealed. All joints to be degressed with carbon tetrachloride prior to application of adhesive. All surplus adhesive to be removed from joints at time of assembly, prior to curing. Grounds for veneers and laminate plastics to be ‘roughened up’ prior to application. h) Adhesives Urea-formaldehyde for all joints and for laminate plastics and veneers to grounds (with platten press). i) Finishes to Timber and Veneers All stained and ebonized finished to be spirit-based and applied to application of general finishes. Samples
required for approval. General Finishes 3 coats polyurethane lacquer, cut down between coats 1 and 2, and 2 and 3 with fine wire wool – matt finish.
Application to be in accordance with manufacturers instructions. All planner marks to be sanded out, timber and veneers to be left with a fine sanded finish prior to application
of finishes. Do not scale drawings. If in doubt, ask. Construction can be varied only in consultation with Designers.
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Setting out rods to be approved and prototype submitted prior to manufacture of batches. j) Gypsum Partitions All partitions are to be fixed firmly to ceiling channels and on floor with positive non-corrosive screws and in
construction and thickness typical of same. All studs are to be 600 c/w vertically and with horizontal bracing when required. Horizontal timber piece
throughout gypsum partition at 1700 high for handing of pictures, etc. must be put up. As and when specified or shown in drawing, gypsum partitions are to be timber framed reinforced, where there
are wall hang on components. Otherwise, all gypsum is to be constructed in non-combustible framing. All plaster boards or gypsum boards are to be butt jointed, crossed lined, filled and rubbed down and screw
fixed. Junctions with existing walls, sills, window frames, mullions and window heads to be carried out with spaced
scribing piece edge with soft gasket such as neoprene. All gypsum partitions are to be properly plastered and levelled to receive wallpaper or painting or painting
works. All gypsum edging and corners are to be protected with 12mm wide aluminium angle. All markings on gypsum bard are to be removed or sealed over with sealer paint if it is determined that the
markings may affect painting or wallpapering works. For partitions specified to have 50mm fibre glass insulation, sandwich between the gypsum boards,
partitioning works should be from floor to underside of slab. Contractors are to note that all partitioning works are to be lined and plumb and inspected by the
Consultant/Designer before construction. 1.2 PAINTING & DECORATING a) Paints Generally All materials for painter’s works shall be of the best grade and obtained from an approved manufacturer.
The Painter’s materials shall be used strictly in accordance with the manufacturer’s printed instructions. Materials shall be delivered to the site in their original sealed and branded containers. The mixing of materials of different brands before or during application will not be permitted. Brushes, pails, kettles and other implements or tools used in painting and preparation of works shall be clean and free from foreign matters. They shall also be thoroughly cleaned before being used for different types of classes of material or colours.
b) Priming Generally A priming coat of appropriate type and quality for the surface concerned shall be applied to all surfaces,
after initial preparation as described under workmanship clauses has been completed. c) Priming on Metal Galvanized metalwork shall be primed with calcium plumbate primer.
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d) Priming on Wood Woodwork shall be primed with an approved aluminium wood priming paint. Priming of joinery shall be
applied on site after the Interior Designer has approved such joinery before it is fixed. Prime backs of all frames and other joinery, which will be hidden in the work.
e) Knotting Knotting shall mean the application of two coats of best quality Shellac Knotting to BS 1336. f) Stopping Stopping shall be with approved filler used strictly in accordance with the manufacturer’s instruction. g) Oil Paints The paints for undercoats and finishing coats on metal and wood shall be ‘ready mixed’ alkyd resin based
paint. The paint for finishing coat shall be wither satin finish of full gloss finish, as shown on Particular Specification.
h) Lacquer The clear and colored lacquer shall be polyurethane non-tinted or tined lacquer of best quality obtained from
an approved manufacturer. i) Workmanship Preparation of Work Area Before the commencement of and during the painting and decoration work or the preparation of it, every
possible precaution shall be taken by the Contractor to keep down dust, including vacuum cleaning each room before hand, and if necessary and approved by the Consultant, the dampening of floors. No paint of any kind shall be applied to works which are damp, and all surfaces shall be freed of all loose matter, efflorescence of salts, dust, etc., and treated with non-dusting compound before the application of paint. Pre-primed, primed or undercoated work shall not be left exposed or in an unsuitable condition for an undue period before completion of the painting process. Metal or other fittings such as ironmongary, etc. not required to be painted shall first be fitted and then removed before the preparatory process is commenced. When all painting has been completed, the fittings shall be cleaned and re-fixed in position. Paints shall be stirred in their original container until smooth before use and thinning or dilution of paints shall be in strict accordance with the recommendations of the manufacturer in each case. The first set of brush strokes for any coats shall be finished with a light stroke either vertical or parallel to the grain in the case of timber.
j) Preparation of Surfaces All surfaces to be painted shall be properly prepared in accordance with the manufacturer’s
recommendations. Plastered and plain-face surfaces shall have all cracks and other defects cut out and filled with hard plaster, the filling shall be struck off level with the surrounding surface and allowed to dry out thoroughly. Metal work shall have all rust scale and grease removed with a wire brush. Metal work delivered to the site primed is to be thoroughly inspected when received on site and all unsatisfactory priming removed and the surface prepared and rimed. All blemishes shall be rubbed down and all pits filled. Damaged priming is to be touched up after preparation. Wood surfaces shall be cleaned off and rubbed smooth and even with fine glass paper. The preparation of wood surfaces shall include for stopping and filling as described and as directed by the Designer, and for rubbing down and bringing to a smooth surface. Plastered surfaces shall be allowed to thoroughly dry out before paint is applied. All coats shall thoroughly dry before subsequent coats are applied.
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k) Colours All tints of paint or other decorative material shall be selected and approved by the Consultant and each
coat shall all differ noticeably from the subsequent coat. l) Covering Capacity The Contractor must satisfy himself as to the covering capacity of all paints according to the absorption of
the varying surfaces and should allow in his prices accordingly. m) Application of Paints The application of paints must be sufficient to give solid colour in the number of coats specified. All surfaces
shall be cleaned, free from all dirt, grease, oil or other deleterious matter. No paint shall be applied to damp surfaces. All coats of paint must be thoroughly dry before subsequent coats are applied, and rubbed down with fine waterproof abrasive where necessary.
n) Painting of Metal Prepare as described, prime with the appropriate primer and paint two undercoats and one finishing coat of
gloss paint on metal internally and externally. o) Oil Paints Oil paints shall be applied on to prepared and primed surfaces with two undercoats and one finishing coat. p) Polyurethane Lacquer The polyurethane lacquer to wood surfaces shall be applied in three coats strictly in accordance with the
manufacturer’s instructions. Lacquer applied to large surfaces such as door faces edges, etc. should be sprayed in a spray booth,
offsite, by a specialist and sanded down and polished to a final thickness of 1mm. Only the highest quality furniture standard lacquer work will be accepted. The Contractor must allow for all surfaces, internal and external, to be lacquered, if lacquer work is referred on drawings, in his costing. Difficult areas to spray, sand and polish must be brought to the attention of the Designer before commencement of work. Samples of lacquer work must be supplied to the Consultant to establish a standard.
q) Cover Up and Protection Cover up all floors, fittings, etc., with dust sheets before executing any painting work. Paint splashes, spots
and stains shall be removed from floors, woodwork, glass, etc., all damaged work shall touched up and the whole of the work left clean and perfect on completion. Cover up and protect all finished painting and decoration after completion of the work and make good any damage done by following trades such as carpet layers, curtain hangers, furniture installers, etc.
1.3 WALLS & WALL FINISHES
Examine all surfaces to receive wall covering and report to the Consultant in writing, on conditions that would
detract from a perfect installation. a) Workmanship
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Installation shall be made by a Contractor whose operatives are fully trained to perform the work in a neat and workman like manner. All seams must be tightly and neatly butted. All air pockets and bubbles eliminated and there must be a firm bond of all the wall-covering to the under-laying surfaces on all the wall areas. Seams must be made at least four inches from the inside, the outside corners and horizontal seams will not be accepted. Wall-covering surfaces shall be cleaned as the work progresses and all paste residues must be removed.
b) Hanging Instruction Hanging instruction must be obtained from manufacturers for each wall covering type and are to b used to
form the specification for each specific wall-covering application. c) Adhesive Only the manufacturer’s recommended adhesive to be used. d) Bricks Shall be solid, even shape, well burnt and complying to SS 103 with min compressive strength 20MN/m2 Bricks use for external walls must not have hairline cracks on the surface. e) Concrete Blocks Load Bearing Blocks shall be even in shape, square, well matured and dense that is of Class A with
minimum compressive strength of not less than 5.6MN/m2 complying to SS 76(M) Non Load Bearing Blocks shall comply with SS 271 with minimum compressive strength of 3.2MN/m2 f) Damp Proof Course Shall be bitumen or equivalent proprietary sheets or membrane complying with BS 6398 Class B. Must be provided and laid continuously without any break at all walls in direct contact with the ground. g) Mortar Shall be Portland Cement with cement complying with SS 26. Only river sand is used for mortar mix.
Mix ratio of 1:6 by volume for internal walls and 1:3 for external walls. Use plasticiser as recommended by manufacturers.
External mortar to include waterproof additive of “Elastiment Superior Additive 200”. h) Bonding, Holdfast and re-enforcements. Generally in stretcher bond unless fair faced finish, of which direction from Consultants is required. Provide all accessories as required like holdfasts, mesh etc for holding the mortar or plastering. Should reinforced brick or blockwork be required, to provide mesh reinforcement at every 4th course. i. Wall Stiffeners Provide wall stiffeners where required and specified by Structural Engineer.
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1.4 TEXTILE FLOOR COVERING General a) Scope of Contract The work comprised the supplying, making up, laying and fixing in all respects of textile floor coverings. b) Samples The Contractor will be required to supply a minimum 1m2 sample of each material type in each selected
colour and or pattern. The Contractor will also be required to supply samples for each type of carpet, including seaming, cutting
and fitting to floor services and carpet skirtings, if any. These samples should show perfect matching. The samples should be approved by the Consultant and serve as a standard for finish accuracy. c) Planning Drawings All plans showing widths and methods of laying in all areas are required to be approved by the Consultant
prior to the commencement of work. The Contractor can be provided with copy negatives of the floor plans to assist his work, if these are
required. d) Protection of Materials The protection of all materials shall be the Contractor’s responsibility. No damaged materials are to be
installed. Any damaged or faulty material is to be replaced at no additional charge. e) Co-ordination of Other Trades Co-ordination with other trades is necessary to ensure that materials may be properly installed and
substantially fixed true and level, shall be the Contractor’s responsibility. f) Maintenance Recommendations Supply for Employer’s use, duplicate copies of manufacturer’s instructions for short and long term cleaning
and maintenance of all material installed. If these are at variance with the accompanying maintenance manual.
g) Material Widths The planning should be based on the use of widest possible widths handle-able to suit area sizes with the
minimum amount of seaming. Access to the spaces must be taken into account. h) Preparation of Sub-Floor The sub-floor shall be prepared in the following manner: - Any highs spots shall be ground down to provide a totally flat and level surface for acceptance of Textile
Floor covering. If the high area is too large to grind down, it shall be ramped by use of latex levelling compound.
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Any hollows or concave damages shall be filled to finished floor level by use of latex levelling compound. Where the floor is exceptionally dusty or if direct bonding installation is required, the floor shall be sealed by
use of manufacturer’s recommended sealant. If the sub-floor should be either too hard or too soft to accept the standard concrete nail supplied with
tackless gripper, the floor shall be drilled and plugged so that the gripper may be screw fixed. i) Installation No damaged materials are to be installed. Any damaged or faulty material is to be replaced at no additional
charge. Co-ordination with other trades as necessary to ensure that materials may be properly installed and
substantially fixed true and level. The planning should be based on the use of widest possible widths handle-able to suit area sizes with the
minimum amount of seaming. Access to the spaces must be taken into account. The textile floor covering should be installed flat and taut enough to ensure that traffic and the movement of
furniture over its surface does not cause rocking to take place. Direction of seams to be agreed with Consultant.
All seams to be heat seamed. All joints to be strong enough to permit the textile floor covering to be
stretched and not break down under traffic. Where applicable, pattern is to match and the pile lay is to be in the same direction, the pile must not be caught in the seam and the seam must lay as flat as possible. All seams to lay straight.
Cross seams will not be accepted. All plans showing widths and methods of laying in all areas are required to be approved by the Designer
prior to the commencement of work. Plans to assist his work, if these are required. Carpet to be installed over a fire-retardant treated 40 oz. yd. 2 weight hairs and jute under felt held at the
perimeters and all opening on tackless grippers. j) Floor Service Access Allowance should be made for cutting and fitting to service access boxes. These boxes to be supplied and
suitable adjusted by other. No carpet edging nor fixings to be visible. k) Completion The whole working area should be cleared of tools, waste, etc., and the job examined for lumps and
tightness, and rectification made where necessary. All stay tacks to be removed and complete carpet area hovered.
l) Guarantees Guarantee of materials and workmanship.
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The Contractor will be required to give a guarantee of a minimum of 5 years for the textile floor covering structure, yarn, underlay and or secondary back, workmanship and all proprietary equipment and materials used in the installation. The Contractor will also be required to give a guarantee that no racking or expansion will take place to cause folds, either in the cloth or at the seams, after the initial laying time.
m) Defective Work Should any defects occur with the Defects Liability Period, such defective work shall be removed and
renewed to the Designer’s satisfaction and any work disturbed as a consequence shall be made good at the carpet Contractor’s expense.
n) Space An additional margin of 2% (of gross carpet area) of the same quality, colour, batch and pattern to those
installed and the spare carpet shall be delivered and hand free to charge to the Employer. 1.5 WINDOW BLINDS a) Scope of Contract The work comprises of the supplying, making up, installing and fixing in all respect of vertical louvered
window blinds. b) Planning Drawings All plans indicating the widths and positions of blinds are required to be approved by the Consultant prior to
the commencement of work. The Contractor can be provided with copy of negatives of the floor plans to assist his work, if these are
required. c) Protection of Materials No damaged materials are to be installed. Any damaged or faulty material is to be replaced at no additional
charge. d) Co-ordination of Other Trades Co-ordination with other trades is necessary to ensure that materials may be properly installed and
substantially true and level. e) Maintenance Recommendations Supply for Employer’s use, duplicate copies of manufacturer’s instruction for short and long term cleaning
and maintenance of all materials installed. 1.6 GLAZER a) Glass Submit samples not less than 150mm square of the various types of glass and obtain approval before
cutting panes. All glass shall comply with BS 952 and shall be of accurate size with clean undamaged edges and surfaces,
which are not disfigured.
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Toughened glass and laminated glass shall be manufactured to precise glazing sizes and with a permanent identification mark in a position, which is visible but not prominent after fixing.
Mirror glass shall have a copper backing over the silver as well as the protective paint coating together with
an additional backing of aluminium foil. Louvre blades shall have edges truly parallel and ground to remove sharp arises. b) Glazing Compound and Accessories Glazing compounds, including putties, shall be of a type recommended by the window and glass
manufacturers and suitable for tropical use. Distance pieces and location blocks shall be of PVC with a thickness equal to the specified space between
glass and bead and of a depth to give not less than 6mm cover of sealant. Setting block shall be of lead, sealed hardwood or nylon. Sleeves and washers for fixing mirrors shall be polyethylene. c) Glazing Generally Glazing shall be carried out in accordance with CP 152. Ensure that rebates are dry and clean and have been primed or sealed as required. Setting and location blocks shall be used in panes of ordinary glazing over 0.2m2 and with all sizes of
laminated glass, toughened glass and factory made double-glazing units. Distance pieces shall be provided to all panes where a non-setting compound is used and they shall not be
located coincident with setting and location blocks. In laminated and toughened glazing or with factory made double-glazing units the positions and sizes shall be as recommended by the glass or unit manufacturer.
d) Compound Glazing Glazing in compound or putty shall be executed with proper bed and back putties, sprigs, clips and splayed
and mitired front putties. The back putties shall be trimmed off flush with the tops of the rebates and the splayed front putties shall be trimmed off flush with the tops of the rebates and the splayed front putties shall be finished 3mm back from sight lines to allow for scaling between glass and putty with paint.
e) Bead Glazing Take out beads which have been loosely pinned in by the surround manufacturer, ease and re-fix timber
ones with countersunk brass cups and screws or rust-proofed panel pins at an adequate number of points to prevent flexing or movement.
Glaze external glass with beads and compound. There shall be a 3mm bed of compound both sides of and
around the glass. Glaze internal glass with beads and glazing tape. Glazing tape shall pass round both sides of the glass, be
mitired at corners, and trimmed off flush with the beads and rebates. f) Gasket Glazing
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Ensure that surfaces to which the gaskets will be fixed are free from dirt, grease, burrs, weld spatter, other projections and are smooth and undisturbed.
g) Silicon joints and gaps required in glass panels and doors should not exceed 4mm wide. h) Mirror Fixing Fix mirrors with proprietary concealed fixing system or with chrome plated dome headed screws. Do not distort when tightening fixings. Use spacer washers or buffers to compensate for irregularities in wall
surfaces. Use sleeves and washers to prevent contact between mirror and fixings. i) Cleaning and Protection Do not use painted or stuck on indicators on solar control or colored glass. Whitewash may be used on
ordinary glass but must be restricted to small central areas of panes. Seal compounds and putties as recommended by their manufacturers. Remove all smears and excess compound and leave clean inside and out and free from scratches. Replace all glass and fixing materials broken or damaged before Practical Completion and redecorate. 1.7 TILES a) All tiles are to be approved by the Consultant. Samples are to be submitted for approval prior to order. b) Laying Tiles Ensure that sub-surfaces are dry, true to plane and level, clean and free from contamination and loose
areas. Start external wall tiling from the top and work downwards. Set out tiles so that our tiles are kept to a minimum and where they do occur is as large as possible. Lay out
joints in straight unbroken lines. Horizontal joints in adjacent walls shall align. Carry movement joints through the full depth of tile and bedding. Partially fill with filler and finish flush with
sealant to the manufacturer’s recommendations. Neatly cut and fit tiles around obstruction. Cut and grind edges of tiles shall be fully bedded. Clean and polish tile surfaces thoroughly upon completion. c) Bedding Wall Tiles in Mortar Soak tiles to suit the various types of tiles and allow draining. Wet backgrounds just sufficiently to prevent excessive absorption of water from the bedding mortar. Fill any deep keys or frogs and evenly butter the entire back of each tile with cement mortar (1:3) to give a
finished bed thickness of 6mm. Place tiles and firmly tap into positions ensuring a solid bedding under the whole tile and proper adhesion over the whole of the background and the tile back.
Grout joints not exceeding 3mm wide with neat white cement. Joint and point joints exceeding 3mm wide
with white cement and sand (1:3).
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d) “Replacement of tiles” will include hacking out existing tiles, preparation of levels to match and
accommodate the new thickness of new finish inclusive of preparation of surfaces to receive new tiles. Areas where 2 types of finishing or colour must be separated by 3mm thick stainless steel of brass strip embedded into the joint.
1.8 CEILING a) Installation Fix ceiling materials in accordance with manufacturer’s recommendation ensuring compliance with design
and performance requirements. Set out accurately to give level soffits free from undulations and lipping, with all lines and joints straight and parallel to walls.
Ensure that edge tiles/sheets are not less than half in width or length. Cut and fit tiles/sheets around recessed light fittings, air-conditioning diffusers, sprinkler heads and the like.
Form openings for access panels together with additional trimming and framing, etc. Deflection between supports of any part of suspended ceilings shall not be more than 1/450 for spans up to
1830mm and 1/600 for spans over 1830mm. b) Metal Support System Metal support systems shall be installed by the Contractor in conjunction with the ceiling lining manufacturer.
All ferrous metals shall be rust-proofed. Hangers shall be substantial and sufficient to prevent excessive deflection in the ceiling. Suspension by means of wire will not be permitted. Additional hangers and support work shall be provided at recessed light fittings, diffusers and access panels, etc.
c) Samples Sample of ceiling boards/hangers, etc. are required to be submitted for approval and mock up may be
required, if necessary. d) Plasterboard Lining Plasterboard shall be 12.7mm thick tapered edge gypsum or glass fiber plasterboard to receive direct
decoration complying with BS 1230. Boards shall be fixed with the ivory surface outward and tapered edges lightly butted. End joints shall be
3mm wide and staggered. Supports shall be provided at all edges of boards. Fixing to timber shall be by means of 2mm diameter small flat head nails 40mm long. Nail heads small flat
head nails 40mm long. Nail heads shall be driven home to form a shallow depression but not to break paper.
Joints and finish boards in accordance with the manufacturer’s instructions to achieve a flush seamless surface ready for decoration.
1.9 METAL WORKER a) Submit full shop drawings of all steel works. All steel works must be duly protected from the weather
elements whilst in store or installed. b) Steel (hot rolled steel) to comply with BS 4 Part 1 and made from steel complying with BS 4360. Hot rolled
steel bars to comply with BS 4449.
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c) Cold rolled sections to comply with BS 2994 from steel complying to BS 1449 Part 1. d) Steel plate to comply with BS 4360. And steel sheet and strips to BS 1449 Part 1. e) Steel tubes to comply with BS 1387 f) Steel mesh to comply to BS 1052 g) Galvanized Steel shall comply to BS 729, entirely coated in one operation with surface clean and uniform
complying to BS 1367 with fittings complying to BS 1256. h) Stainless steel (type 304) to comply to BS 1449 Part 2 or BS 3014 as appropriate. i) All railings to be designed to horizontal/lateral loading in accordance to Table 4 of the 4th Schedule of BCA
Regulation 1989, with height of railing at 1100 high and gaps of not more than 100mm. j) All welding must be full and through and in accordance to BS 5135, BS 5950, BS 449 and BS 4870 and
4871. Weld splatter and oxides on exposed surfaces to be cleaned, treated and matched with finished surface.
k) Do not leave exposed surfaces or surfaces damaged due to welding or jointing works to corrosion. Such
areas to be appropriately protected. 1.10 LIGHTNING PROTECTION a) All metal structure and cladding must be fully bonded electrically to ensure continuity of building envelope
and be grounded by earthing jumper cables, tapes and connections. b) Provide Lightning arresters as required. 1.11 BUILDING TOLERANCES a) Allow for all building tolerances, movements due to weather, heat noise and aircraft vibration from jet
engines etc. b) Allow for building expansion joints to main building including structure( main and foundations) , floor slab,
roof and structural frames. c) Allow for movement and settlement of ground.
III PART 3 – M&E SPECIFICATIONS 1.1 M&E SPECIALIST WORKS a) This M&E section is considered specialist works which is carried out under the appropriate trade and
professional engineering license. In all cases, the system design, installation, testing and commissioning of the as built or installed M&E works must be endorsed, submitted (including shop drawings) and be approved by the relevant authorities including any licensing approvals.
b) The itemized breakdown of the Tender Price as listed shall form only as an indication of the breakdown
value for this contract works. c) Supply and installation of M&E equipment shall include supply, delivery, installation, testing, commissioning
and other associated ancillary accessories.
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d) In carrying out the works the specialist licensed contractor and inclusive of the Engineer (CPE) must liaise directly with the Consultants to progress the works not only on site but with the authorities, CAG, CAAS etc.
1.2 ELECTRICAL WORKS a) HV switchboards shall include circuit breakers, metering, BMS interfacing points, protection devices,
terminal blocks, cable boxes, floor frames, batteries and other associated ancillary accessories as specified. b) Power transformers shall include all control panels, cable boxes, fittings and other associated ancillary
accessories as specified. c) LV switchboards shall include circuit breakers, metering, BMS interfacing points, protection devices, terminal
blocks, cable boxes, surge arrestors, heaters and other associated ancillary accessories as specified. d) Capacitor banks shall include harmonic filters, capacitors, wiring and other associated ancillary accessories
as specified. e) Generator sets shall include AMF Panel, synchronized panel (if applicable), with associated wiring, exhaust
ducting, silencer, day tank and pump and other associated ancillary accessories as specified. f) Busbar systems shall include tap off units, end feed units, end caps, joints, brackets, integrated with
dedicated earth bar and other associated ancillary accessories as specified. g) Distribution boards shall include busbars, moulded case circuit breakers, miniature circuit breakers, residual
current circuit breakers, time switches and other associated ancillary accessories as specified. h) Final circuits for lightings shall include wirings, cable support and containment systems, lighting switches
and other associated ancillary accessories as specified. (50m run) i) Final circuits for small power and isolator shall include wirings, cable support and containment systems,
switch socket outlets, isolators and other associated ancillary accessories as specified. (50m run) j) Floor trunking installation shall include junction boxes, vertical access boxes, service outlet boxes, fittings
and other associated ancillary accessories as specified. k) Light fittings and fixtures shall include lamps, control gears, starters, brackets and other associated ancillary
accessories as specified. l) External street light fittings and fixtures shall include lamps, control gears, starters, brackets, lamp posts and
other associated ancillary accessories as specified. m) Exit signs and emergency light fittings and fixtures shall include lamps, control gears, starters, brackets,
battery packs and other associated ancillary accessories as specified. n) Security systems shall include uninterruptible power supply, servers, workstations, equipment racks,
application software, firewall software, cablings and other associated ancillary accessories as specified. o) Power, data and control cabling systems shall include cable support and containment systems and other
associated ancillary accessories as specified. p) TV / FM outlets shall include coaxial cable, TV / FM outlets, cable support and containment system and
other associated ancillary accessories as specified. q) CATV/MATV/TVRO systems shall include head-end equipment, cables, splitters, tap-off units, coaxial
cables for TV/FM outlets and other associated ancillary accessories as specified.
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r) Head-end equipment for CATV/MATV/TVRO system shall include amplifiers, booster units, antennas, cabinets, power supply units and other associated ancillary accessories as specified.
s) Vehicle barrier systems shall include vehicle barrier units, control panels, intercoms, transponder readers,
cameras, power supply, cables, card transponders or transponder discs and other associated ancillary accessories as specified.
t) Vehicle barrier units shall include safety loop detectors and other associated ancillary accessories as
specified. u) EPS entry and exit stations shall include microprocessor-based controllers, UPS, LED display signs, cash
card readers, intercoms, antennas and other associated ancillary accessories as specified v) PC-based management control stations shall include CPUs, modems, printers, monitors, UPS, application
software and other associated ancillary accessories as specified w) EVCS/PA system equipment shall include equipment paging consoles, racks, amplifiers, tuners, CD players,
fault monitoring panels, over-riding switch, UPS, hardware, software and other associated ancillary accessories as specified
x) Speakers shall include housings, mounting brackets and other associated ancillary accessories as specified. y) Lightning protection system shall include roof conductors, air terminals, equipotential bonding to metallic
parts, down conductors, earth electrodes, earth pits and other associated ancillary accessories as specified z) Main earthling system shall include earth continuity conductors, copper tapes, earth bars, equipotential
bonding, earth rods, earth pits and other associated ancillary accessories as specified aa) Services and maintenance during defects liability or maintenance period shall include the supply of all labor,
materials, tools, transport and everything necessary to carry out scheduled servicing and maintenance as specified.
1.3 FIRE SERVICES a) All works, systems, materials, equipment and installation are to comply to all relevant Authorities especially
the FSSB and Airport Fire Services with approval including all submissions by specialist or professional engineer responsible for the system. The Contractor’s specialist/licensed Fire Services provider or engineer is deemed to understand the requirements of the FSSB Code of practice as required for the Project.
1.4 PLUMBING SERVICES a) All works, systems, materials, equipment and installation are to comply to all relevant Authorities especially
the NEA with approval including all submissions by specialist or professional engineer responsible for the system. The Contractor’s specialist/licensed Plumber/provider or engineer is deemed to understand the requirements of the NEA which includes CBPU, PUB (Sewerage), PUB(Drainage) Code of practice as required for the Project.
1.5 MECHANICAL SERVICES a) All works, systems, materials, equipment and installation are to comply to all relevant Authorities with
approval including all submissions by specialist or professional engineer responsible for the system. The Contractor’s specialist/licensed mechanical sub-contractor or engineer is deemed to understand the requirements of the BCA/Authority which includes CBPU, PUB (Sewerage), PUB(Drainage) if required, their Code of practice for the Project.
END
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MTECH CONSULTANTS
S1/1
SECTION 1 - CONCRETE WORKS
1 REINFORCED CONCRETE WORKS
1.1 General
The reinforced concrete work is to comply with the requirements of the British Code
of Practice BS 8110 "The Structural Use of Concrete" and subsequent revisions
thereof.
So far as is practicable or unless otherwise specified, materials shall comply with the
appropriate latest Singapore Standards or British Standards where the Singapore
Standards do not exist. Where the requirements of the relevant Singapore or British
Standards are in conflict with this Specification, then this Specification shall take
precedence.
Materials used in the Works shall be of the qualities and kinds specified
herein and equal to approved samples. Delivery shall be made sufficiently in
advance to enable samples to be taken and tested if required. No materials shall be
used until and unless approved and materials not approved shall be immediately
removed from the vicinity of the Works at the Contractor's own expense.
Materials shall be transported, handled and stored on the site or elsewhere in such a
manner as to prevent damage, deterioration or contamination all to the satisfaction of
the Engineer. The Engineer reserves the right to inspect any materials to be used on
the Works at any time and at any place of storage.
If required, the Contractor shall supply to the Engineer the appropriate certificate of
compliance with the Standards. Notwithstanding the above, tests shall be carried out
as and when directed by the Engineer in accordance with the relevant Singapore
Standards and/or British Standards.
1.2 Cement
The cement used shall be of approved manufacture. Portland cement shall comply
with the requirements of BS 12 or SS 26. Portland-Blast-Furnance Cement shall
comply with the requirements of BS 146. Sulphate-resisting cement shall comply
with BS 4027. Manufacturer's certificates of test will generally be accepted as proof
of soundness, but the Engineer may require additional tests to be carried out on any
cement which appears to have deteriorated through age, damage to containers,
improper storage or for any other reason. The Engineer may, without tests being
made, order that any bag of cement, a portion of the contents of which has hardened,
or which appears to be defective in any other way, be removed from the site
forthwith. No cement shall be used in the works until it has been passed as
satisfactory by the Engineer.
MTECH CONSULTANTS
S1/2
The Contractor may if the Engineer approves, elect to use types of cement other than
ordinary Portland, but no extra will be paid on account of using a cement priced
higher than the price for the type specified, unless work using such cement is
ordered in writing by the Engineer.
The cement shall be transported to the site in covered vehicles adequately protected
against water. Bagged cement shall be stored in a weather-proof cement store and
shall be taken for use in the works in the order of its delivery into the store. Bulk
cement is to be stored in properly constructed silos. Arrangements for transport,
general delivery, planning, storage and certification shall be fully provided to the
Engineer before orders are placed.
1.3 Aggregates Generally
The fine and coarse aggregates shall be naturally occurring sands, gravel or stone,
crushed or uncrushed, and shall comply with the requirements of Singapore
Standards (SS) 31:1971 or BS 882 "Crushed Aggregate from Natural Sources". They
shall be obtained from a source approved by the Engineer and shall be hard, strong,
durable, clean and free from adherent coatings and shall not contain any harmful
material in sufficient quantity to adversely affect the strength, durability
impermeability of the concrete or to attack the steel reinforcement. They shall not
contain water-soluble sulphur trioxide (SO3) in excess of 0.1%.
1.4 Fine Aggregate
The fine aggregate shall not contain silt or other fine material exceeding 3% by
weight when tested according to the standard method given in BS 812. As a guide,
the field setting test may be used to determine the silt content and should normally
not show more than 10% silt by volume.
The fine aggregate shall not contain organic material in sufficient quantity to render a
mean pH value of 12.2 or lower at a temperature of 110°C, when tested according to
the method in BS 812, Clause 32 on "Organic Impurities". The Contractor shall
screen all fine aggregates as and when required by the Engineer.
1.5 Coarse Aggregate
The coarse aggregate shall be granite or other hard stone from a source approved by
the Engineer. The aggregate shall not contain clay exceeding 1% by weight.
Representative dry sample shall not show an increase in weight exceeding 8% after
immersion in water when tested as laid down in BS 812 Clauses 19 to 21. It shall be
well shaped and its flakiness index shall not exceed 35. The nominal size of coarse
aggregate shall be as stipulated below.
MTECH CONSULTANTS
S1/3
1.6 Aggregate Grading
The grading of aggregate shall comply with BS 882 Clause 5 and shall be within the
limits as shown in Tables 1.1 and 1.2. The grading between the limits specified
above shall be to the satisfaction of the Engineer and when tested as provided for in
this Section, shall approximate closely to the grading of the samples approved by
him. If it should be found necessary, the fine aggregate shall be washed and screened
to comply with the foregoing standards and the requirements of the Engineer.
1.7 Sampling and Testing of Aggregates
Tests shall be carried out on samples of the latter taken at intervals as laid down in
Clause 1.4 below or as required by the Engineer. The method of sampling and the
amount of aggregate to be provided for the tests shall be in accordance with BS 812,
Section One, "Sampling of aggregates". The test shall be those laid down in BS 812,
Sections Two to Six, inclusive. The tests will be carried out by the contractor in the
presence of the Engineer, or his representative. Should a sample fail to comply with
any of the tests, the Engineer may, at his discretion, either the batch from which the
sample was taken, order it be washed and/or screened, or permit it to be used with
variations in the proportions of the concrete mixes specified. Any batch of aggregate
rejected by the Engineer shall be removed from the Works or site forthwith.
MTECH CONSULTANTS
S1/4
Table 1.1 Coarse Aggregate
Percentage by Weight Passing BS Sieves
BS 410:1976
Test sieve
Nominal size of graded
aggregate
Nominal size of single-sized
aggregate
1.5
in. to
3/16
in.
(38
mm
to
5
mm)
3/4
in. to
3/16
in.
(19
mm
to
5
mm)
1/2
in. to
3/16
in.
(13
mm
to
5
mm)
2.5 in.
(64
mm)
1.5 in.
(38
mm)
3/4 in.
(19
mm)
1/2 in.
(13
mm)
3/8 in.
(10 mm)
In.
mm
3
76.2
0
100 - - 100 - - - -
2 1/2
63.5
0
- - - 85 -
100
100 - - -
1 1/2 38.1
0
95 -
100
100 - 0 - 30 85 -
100
100 - -
3/4 19.0
5
30 -
70
95 -
100
100 0 - 5 0 - 20 85 -
100
100 -
1/2 12.7
0
- - 90 -
100
- - - 85 -
100
100
3/8 9.52 10 -
35
25 -
55
40 -
85
- 0 - 5 0 - 20 0 - 45 85 - 100
3/16
4.76 0 - 5 0 - 10 0 - 10 - - 0 - 5 0 - 10 0 - 20
No.
mm
7
2.40 - - - - - - - 0 - 5
Samples of the fine and coarse aggregates approved by the Engineer shall be kept on
site, and shall give a fair indication of the general quality of the aggregates for
comparison with the aggregates delivered during the course of work.
1.8 Storage of Aggregates
All aggregates for concrete shall be stored in bays with drainage slopes or in bins
in such a manner as to prevent segregation of sizes and to avoid the inclusion of dirt
and other foreign materials in the concrete. The storage bays shall be protected from
rainfall in order to prevent excessive changes in moisture content taking place. Each
size of aggregate shall be stored separately unless otherwise approved.
The bottom 300 mm of each stockpile shall not be used in concrete but shall be left
in position throughout the contract to act as a drainage layer.
MTECH CONSULTANTS
S1/5
Table 1.2 Fine Aggregate
BS 410:1976
test sieve
Percentage by Weight Passing BS Sieve
Grading
Zone 1
Grading
Zone 2
Grading
Zone 3
Grading
Zone 4
in
mm
3/8
9.52 100 100 100 100
3/10
4.76 90 - 100 90 - 100 90 - 100 90 - 100
No.
mm
7
2.40 60 - 95 75 - 100 85 - 100 95 - 100
14
1.20 30 - 70 55 - 90 75 - 100 90 - 100
No.
microns
25 600
15 - 34 35 - 59 60 - 79 80 - 100
52
300 5 - 20 8 - 30 12 - 40 15 - 50
100
150 0 - 10 0 - 10 0 - 10 0 - 15
1.9 Water
The water shall be clean and free from harmful matter and shall be from a source
approved by the Engineer, such as the city's potable water supply system. The
Contractor shall make adequate arrangements to deliver and store sufficient water at
the works site for use in mixing and curing the concrete. Water shall comply with
the requirements of the latest edition of BS 3148.
MTECH CONSULTANTS
S1/6
1.10 Reinforcement
(a) Quality
Hot-rolled Mild Steel and High Tensile Steel reinforcement must be obtained from
manufacturers who have been approved in writing by the Engineer and shall comply
with Singapore Standard (SS) 2 or BS 4449 with regard to strength and elasticity.
Cold worked steel bars shall comply to BS 4461. Steel fabric reinforcement shall
comply with SS32 or BS 4483. All reinforcement shall be hammered free from
scale, scraped and wire-brushed free from all loose rust and after such treatment shall
be within the margins over and under which are allowed by the abovementioned
British Standard. It shall not be coated with any grease oil, paint or preservative.
High tensile steel fabric when used shall comply with BS 4483. Strength of steel
for concrete reinforcement shall be as given in Table 1.3.
(b) Where the letter T is used in the structural detailing, it shall mean that such
reinforcement shall be high tensile bars having a minimum characteristic tensile
strength of 460 N/mm2 at a proof strain of 0.002 as tested to BS 4449.
(c) The letter R, where used, shall indicate that such reinforcement shall be
mild steel bars with a minimum characteristic strength of 250 N/mm2.at a proof
strain of 0.002 as tested to BS 4449.
(d) Sampling and control
The Contractor shall furnish, for reinforcement supplied by him, manufacturer's
certificates and these shall be submitted for acceptance by the Engineer, before any
material is brought onto the site. In addition, the Contractor shall, on request,
furnish the Engineer with a test sheet for any batch of bars, giving the results of
each of the mechanical tests required under British Standards.
In the event of any reinforcement being found to be not in accordance with the
British Standards in the course of being worked, it may be rejected by the Engineer
notwithstanding any previous acceptance on the strength of the test certificates and
the Engineer may call for additional tests to be made at the Contractor's expense on
samples taken from the batch of bars from which the faulty reinforcement came. If
the samples do not satisfy the Standards requirements, then the Engineer may reject
the whole batch and require its removal from the works site.
The frequency of sampling and testing shall be according to the following Table 1.4.
MTECH CONSULTANTS
S1/7
Six test specimens are to be prepared from each sample. The length required for
each specimen shall be 300 mm. The deviation in weights and effective cross-
sectional areas shall not exceed those given in BS 4449 and routine sampling shall
be carried out for each nominal size used at the rate of one (1) sample per 1,000
bars or part thereof.
Table 1.3 Strength of Reinforcement
Designation
Nominal Sizes Specified
Characteristic
Strength, fy
at 0.002 proof strain
mm
N/mm2
Hot rolled mild steel
(SS 2, BS 4449 : 1978)
All sizes
250
Hot rolled high tensile
(SS 2, BS 4449 : 1978)
460 Grade
All sizes
460
Cold worked high tensile
(BS 4461 : 1978)
460 Grade
All sizes
460
Hard drawn steel wire
(BS 4482 : 1969)
Up to and including
12φ
485
Table 1.4 Frequency of sampling and testing of reinforcement
Diameter of bar (mm) One sample for tensile and bend tests from each
Under 10
5,000 bars (25 tonnes or part)
10 to 12
3,000 bars (35 tonnes or part)
16 to 20
1,500 bars (45 tonnes or part)
Over 22
1,000 bars (45 tonnes or part)
(e) Cleaning
The reinforcement shall be cleaned free from loose mill scale and loose rust before
being placed in the forms and shall be free from these and from oil, grease or other
harmful matter at the time when the concrete is placed.
MTECH CONSULTANTS
S1/8
(f) Bending
The reinforcement shall be bent cold in an approved bar bending machine. The
bending dimensions and tolerances and the dimensions of end anchorages, hooks,
binders, stirrups, links and the likes shall be in accordance with BS 4466. The
minimum diameter of the former for bending shall be 4 times the bar diameter for
mild steel and 6 times the bar diameter high tensile steel.
(g) Placing
The reinforcement shall be placed in the forms and held firm against displacement,
by approved types of small precast concrete fixing blocks and wire ties, in the exact
position shown in the approved Construction Drawings, or, if not shown, to the
Engineer's approval. Fixing blocks may be left embedded in the concrete in cases
where the Engineer approves. Bars intended to be in contact when passing each
other shall be securely held together at intersection points with tying wire. Binders
and stirrups shall tightly embrace the longitudinal reinforcement to which they shall
be securely wired together or spot welded.
The wire ties used shall be No. 20 S.W.G. soft annealed iron wire ; the ends shall be
turned in from the face of the framework and shall not be left projecting beyond the
reinforcing bars. The reinforcement shall be inspected and passed by the Engineer or
his representative before concrete is placed in the forms. The required amount of
cover over the reinforcement shall be obtained when the reinforcement is placed and
shall be held to this during concreting.
The following tolerances in Table1.5 are generally applicable for reinforcement steel
in place.
Reinforcement wrongly placed shall be re-positioned or replaced by an equivalent
amount of bars in the correct position to the satisfaction of the Engineer.
MTECH CONSULTANTS
S1/9
Table 1.5 Tolerances for reinforcement steel in place
Item
Allowable Tolerance
Size of bar
Nil
Cover
+5mm, -2mm
Height, effective
+5 mm
Position of hook
+50 mm
Spacing
+15 mm
Number of bars
Nil
(h) Laps
Laps shall be as shown in the Drawings. Where not indicated, laps shall be as listed
in Table 1.6.
Fabric reinforcement sheets are to overlap by 300 mm.
Table 1.6 Lap length of reinforcement bars
Lap length in number of bar diameter
Grade of
Concrete
Mild steel reinforcement
High tensile steel reinforcement
Bars with
U-Hooks
Bars without
U-Hooks
Bars with
U-Hooks
Bars without
U-Hooks
30 or better
35
50
37
52
25
39
55
40
57
MTECH CONSULTANTS
S1/10
(j) Welding
Welding of mild reinforcement by electric arc may be permitted by the Engineer
under suitable conditions and with suitable safeguards. Welding shall be carried out
in accordance with BS 5135 "Metal Arc Welding of Carbon and Carbon Manganese
Steels". Butt welds shall be of double V type and two butt weld bend tests shall be
carried out on a specimen prepared to represent each form of butt welded joint used
in the welding. The method of making butt weld test shall be that laid down in BS
709. The specimen shall pass the tests to the satisfaction of the Engineer before
approval is accorded to use the joint which the specimen represents. Tack welds
between reinforcing bars, used merely to fix them in position, shall not be subject
to tests.
1.11 Storage of Reinforcements
The reinforcement shall be stacked tidily in a manner that permits inspection.
1.12 Contractor's Concrete Batching Plant
The Contractor's concrete batching and mixing plant shall be subject to approval by
the Engineer and he should therefore submit his proposal to the Engineer prior to
erection and use.
1.13 Ready mixed Concrete
Ready mixed concrete shall be used for this project. The Contractor shall furnish the
name of his ready mixed concrete Supplier to the Engineer for approval. He shall
make such arrangements as may be required for the Engineer to inspect his Supplier's
works and provide all facilities for samples of cement, fine and coarse aggregates
and admixtures to be selected for testing by an approved PSB accredited laboratory.
Notwithstanding any such inspection having been made and/or approval given by the
Engineer, the Contractor shall take full responsibility for ensuring that all ready
mixed concrete supplied shall conform to SS 119 : 1975 or BS 5328 : 1981 and this
entire Specification. Concrete that does not comply with this entire Specification
shall be rejected and removed from Site by the Contractor at his own expense.
The Contractor shall furnish to and obtain the approval of the Engineer at least one
day in advance of the date set for each casting of concrete, the number of transit
trucks/truck mixer/truck agitators proposed to be used to supply the concrete and the
frequency at which the loads of concrete are to be delivered to the Site.
MTECH CONSULTANTS
S1/11
For each truck load of concrete delivered, the following information shall appear on
the delivery docket :
(1) Name of ready mixed concrete batch plant
(2) Serial number of docket
(3) Date and the license number of the truck
(4) Name of the purchaser
(5) Name and location of job
(6) Specified characteristic concrete strength and the amount of
cement used (kg) or the mix proportions
(7) Quantity of concrete
(8) Time of loading or of first mixing of cement and aggregates,
whichever is earlier
(9) Agreed slump
(10) Maximum size of coarse aggregates specified
(11) Trade name of admixture, if any
(12) The signature of the Supervisor who shall also enter the time of
arrival of the truck and the time of completion of discharge
(13) Position where concrete is placed
(14) Number of cubes taken if any, and cube reference codes
(15) Temperature of mix when received and during the pour
(16) Any other requirements as may be instructed
One copy of the docket shall be given to the Engineer on delivery.
The Engineer reserves the right to instruct the Contractor to change the Supplier in
view of unsatisfactory performance or to rescind his approval for further use of ready
mixed concrete during the progress of the Works if any of the requirements of this
Specification has, in his opinion, not been satisfactorily complied with.
No water in excess of the quantity required in the approved mix shall be allowed to
be added to the concrete to increase its workability affected by elapsed time and/or
temperature.
While it is not being discharged, the concrete in a transit truck/truck mixer/truck
agitator shall be kept continuously agitated.
The concrete shall be placed in its final position and left undisturbed within two
hours from the time when the cement was added to the mix. Deviations from this
time interval may be permitted by the Engineer subject to trial mixes carried out.
MTECH CONSULTANTS
S1/12
1.14 Grades of Concrete
The grades of concrete to be used in the Works shall be as shown in the Drawings.
For each grade of concrete the mix shall be designed so that, when tested in
accordance with this Specification the minimum works cube strength and the
minimum and maximum cement contents shall be as set out in Table 1.7.
Attention is drawn to the fact that the specified strengths given in Table 1.7 are
minimum strengths. Whilst it is appreciated that the Contractor may use statistical
methods, values of sets of 28 day works cube test shall not be considered
satisfactory if the requirements of Clause 1.19 in this Specification are not met.
Preliminary trial mixes of each of the classes of concrete to be used in the Works
shall be made by the Contractor to ensure that, the mix as designed will comply with
the strength and other requirements of this Specification.
Trial mixes shall be carried out at such a time so that final mixes to be used shall be
agreed well in advance of requirements.
For each grade of concrete, a set of 8 cubes shall be made from each of 3
consecutive batches. Four cubes from each set of 8 cubes shall be tested at 7 days
and the remainder at 28 days. Cubes shall be made, cured, stored and tested all in
accordance with SS 78: 1972. Preliminary cube strength tests results shall exceed the
minimum strength requirements of Table 1.7 by not less than 33%.
In order to satisfy the Engineer that the workability of the proposed mixes is such
that the concrete can be readily worked into corners, recesses and around all
reinforcement without segregation or "bleeding", the Contractor shall carry out a
series of workability tests on the preliminary trial mixes in accordance with SS 78 :
1982.
No concrete shall be placed until the Supplier has received the Engineer's approval
for the mix proportions.
The Contractor shall not vary the approved mixed proportions, size or grading of
aggregates nor alter the sources of supply of materials without the prior approval of
the Engineer.
Alterations to mixes already approved by the Engineer shall be subjected to further
trial mixing as specified.
The Engineer may order alterations to mix proportions should works cube test results
indicate that such changes are necessary in order to comply with specified strength
and workability requirements. No additional payment shall be made in respect of
such variations to mixes whether ordered by the Engineer or requested by the
Contractor himself.
MTECH CONSULTANTS
S1/13
1.15 Cement Content
For ordinary reinforced concrete, the cement content for water retaining structures
and structures in contact with water/ground, shall not be less than 400 kg/m3 unless
written approval is obtained.
1.16 Admixtures
All admixtures shall comply with BS 5075 Parts 1 and 3.
(a) No admixtures will be permitted without written permission and in no
circumstances will chloride admixtures be allowed. In the event of
permission being granted in principle the tests described in the Specification
shall be carried out with the intended proportion of admixture incorporated
and comparison shall be made with concrete manufactured without the
admixtures to prove that the density has not been reduced below 2320 kg/m3.
(b) When admixtures are used on the Works, very strict control is to be maintained to
ensure that the correct quantity of admixture is used at all times. Admixtures
containing chlorides shall not be used.
MTECH CONSULTANTS
S1/14
Table 1.7 Grades of Concrete
Grade of
concrete
50
45
40
35
30
25
20
15
10
Minimum cube
crushing
strength, in
N/mm2
7
day
40
35
30
26
23
19
15
11
-
Minimum cube
crushing
strength, in
N/mm2
28
day
50
45
40
35
30
25
20
15
-
Minimum
recommended
cement content
in kg/m3 of
fully
compacted
concrete
430
415
400
390
375
330
300
290
250
Maximum
cement content
in kg/m3 of
fully
compacted
concrete
550
550
550
550
550
550
550
550
550
Maximum
water/cement
ratio
0.45
0.45
0.50
0.50
0.50
0.50
0.55
0.55
0.65
MTECH CONSULTANTS
S1/15
1.7 Requirements for Mix Design
(a) The Contractor shall submit details of his mix design to the Engineer for his
provisional approval. Details submitted shall include:
(i) the type and source of cement
(ii) the type and source of aggregate
(iii) the grading details, in tabular and graphical form, of the fine and
coarse aggregates
(iv) the grading details, in tabular and graphical form, of the combined
aggregates, together with details of the proportions in which the fine
and coarse aggregates are to be combined
(v) the aggregate-cement ratio by weight
(vi) the water-cement ratio by weight
(vii) the workability in terms of both slump and compacting factor having
due regard to the final location and dimensions of the concrete
(viii) the target mean strength and the current margin.
(b) The concrete mix shall be designed to have at least the required minimum cement
content and to have a mean strength greater than the required characteristic
strength by at least the current margin.
(c) The current margin for each particular type of concrete mix shall be taken as
having the smaller of the values given by (i) or (ii).
(i) 1.64 times the standard deviation of cube tests on at least 100
separate batches of concrete of nominally similar proportions of
similar materials and produced over a period exceeding 5 days but
not exceeding 6 months by the same plant under similar supervision,
but not less than 1
/3 of the characteristic strength for concrete
grades 10 or 15, or 7.5 N/mm2 for concrete of grade 20 and above.
(ii) 1.64 times the standard deviation of cube tests on at least 40 separate
batches of concrete of nominally similar proportions of similar
materials and produced over a period exceeding 5 days but not
exceeding 6 months by the same plant under similar supervision, but
not less than 1
/3 of the characteristic strength for concrete grades 10
or 15, or 7.5 N/mm2 for concrete of grade 20 and above.
MTECH CONSULTANTS
S1/16
(d) When there are insufficient data to satisfy (i) or (ii) above, the margin for the
initial mix design shall be taken as 2/3 of the characteristic strength for
concrete of grades 10 or 15, or 15 N/mm2 for current margin only until
sufficient data are available to satisfy (i) or (ii) above. However, when the
required characteristic strength approaches the maximum possible strength of
concrete made with a particular aggregate, a smaller margin but not less than
7.5 N/mm2 shall be permitted for the initial mix design subject to the prior
approval of the Engineer.
(e) Evidence shall be submitted to the Engineer for each grade of concrete
showing that at the intended workability, the proposed mix proportions and
manufacturing method will produce concrete of the required quality.
(f) Three separate batches of concrete shall be made for trial mixes using
materials from the proposed supply and under full scale production
conditions. Sampling and testing shall be in accordance with BS 1881.
(g) The workability of each of the trial batches shall be determined and four cubes
made from each batch for test at 28 days. A further four cubes from each
batch shall be made for each test at 3 days and 7 days. The trial mix
proportions are adequate if the average strength of the 12 cubes tested at 28
days exceeds the specified characteristic strength by the current margin
minus 3.5 N/mm2 or if twelve tests at an earlier age indicate that it is likely
to be exceeded by this amount.
(h) Trial mixes will be required to demonstrate that the maximum free water/cement
ratio is not exceeded. Two batches shall be made in laboratory with cement
and surface dry aggregates known, from past records of the suppliers of the
material, to be typical. The proposed mix proportions shall not be accepted
unless both batches have the correct cement content and a free/water cement
ratio below the maximum specified value at the proposed degree of
workability. For this purpose, existing laboratory test reports may be
accepted instead of trial mixes only if the Engineer is satisfied that the
materials to be used in the structural concrete are likely to be similar to those
used in the tests.
(j) During production, the Engineer may require trial mixes to be made before a
substantial change is made in the materials or in the proportions of the
materials to be used.
MTECH CONSULTANTS
S1/17
(k) During production, adjustments of mix proportions can be made, in order to
maximize the variability of strength to approach more closely the target mean
strength, provided the express approval of the Engineer is obtained. Such
adjustments are regarded as part of the proper control of production but the
specified limits of minimum cement content and maximum water/cement
ratio shall be maintained. Changes in cement content shall have to be
declared. Such adjustments to mix proportions shall not be taken to imply
any changes to the current margin.
(l) A change in the current margin used for judging compliance with the
specified characteristic strength will become appropriate when the results of
a sufficiently large number of tests show that the previously established
margin is significantly too large or too small. Recalculation of the margin
should be carried out in accordance with sub-clause (c) but, although a
recalculated margin is almost certain to differ numerically from the previous
value, the adoption of the recalculated value would not generally be justified
if the two values differ by less than 18 per cent when based on tests on 40
separate batches; less than 11 per cent when based on tests on 100 separate
batches or less than 5 per cent when based on tests on 500 separate batches.
(m) On adoption of a recalculated margin, it becomes the current margin for the
judgement of compliance with the specified characteristic strength of
concrete produced subsequently to the change.
1.18 Quality Control Sampling and Testing
(a) Initial sampling and testing of cement, aggregates, water, plant and concrete trial
mixes shall be conducted as stated above.
(b) Routine quality control tests shall subsequently be conducted throughout the
whole period of this Contract by the Contractor for all concrete works. A
record of these tests shall be kept on the works, identifying particular
portions of concrete in the works with the respective samples and tests made.
Copies of all test records shall be submitted to the Engineer promptly on
completion of each respective test.
The tests shall be carried out for the following items in Table 1.8.
MTECH CONSULTANTS
S1/18
Table 1.8 Routine quality control tests
Item
Tests
Remarks
Aggregates Field silt test for sand One test per day
Surface moisture of coarse
aggregate
As directed by the Engineer after
rain. Adjustment of mixing water
is necessary for any change.
Surface moisture of fine aggregate
Twice a day.
For any change adjust the quality of
water
Concrete Slump tests or Compacting Factor
test on fresh concrete
For first batch of each placement,
and twice more per day during
mixing.
Value should be within +25 mm of
required slump.
Cubes for compressive strength
See sub-clause (c) below
Minimum cement content See sub-clause (c) below
Specimens for flexural strength,
and core tests.
To be sampled if and when
directed. Make 3 specimens from
each sample.
Plant
Inspection of gauges Daily check for accuracy required
before use.
Limit of tolerance to be +2%.
MTECH CONSULTANTS
S1/19
(c) Compressive Strength Tests on Concrete
(i) Concrete strength will be based on tests on cubes at 28 days age. The
practical advantages of testing at 3 or 7 days or by use of accelerated
curing methods are recognised and where carried out, may be
allowed to assist the Engineer and the Contractor in the interim for
provisional acceptance of the concrete strength and quality on a pro-
rata basis. Final acceptance, however, will be based on the 28-day
cube test results or the test results for cube strengths in excess of the
targeted 28 day strength, if achieved earlier.
(ii) The characteristic strength is defined as the 28-day strength below
which 5% of the tests fail.
(iii) The concrete quality control system adopted is a statistical one
depending on the standard deviation, s, of the 28-day cube test
results where
s = (x - m)2
n - 1
and x = an individual result
n = number of results
m = mean of n results
(iv) The concrete shall be sampled according to one of the rates specified
below in Table 1.9 below as selected by the Engineer who will be
expected to choose a rate applicable to the degree of control of
workmanship and material quality exercised by the Contractor as
well as the nature of the work. Ordinarily, Rate 1 is applicable to
highly stressed and to critical members such as columns, transfer
beams and cantilevered beams, Rate 2 to ordinary work and Rate 3
is for mass concrete work.
Table 1.9 Rate of Sampling
Rate 1
Rate 2
Rate 3
Volume of Concrete per
Sample
10 m3
or 5 batches
50 m3
or 10 batches
100 m3
or 20 batches
whichever is the lesser volume
MTECH CONSULTANTS
S1/20
(v) Two cubes shall be made from each randomly selected sample under
Rate 1. A single cube shall be made from each randomly selected
sample under Rates 2 and 3. All the concrete in any one sample shall
be taken from a single batch. Sampling shall be taken at the point of
discharge of the mixer, or in the case of ready-mixed concrete, at
the point of discharge from the delivery truck.
(vi) The concrete complies with the specification if :
A. The average strength of any group of 4 consecutive test cubes
exceeds the characteristic strength by half the current margin
(See Tables 1.10 and 1.11 below).
B. Each individual test result is greater than 85% of the
specified characteristic strength,
or
C. For small projects, the acceptance criteria is based on a
group of four (4) concrete cubes.
C.1 Each of the four (4) cubes in a group has a strength not less
than the specified characteristic strength
or
C.2 Not more than one cube has a test strength less than the
specified characteristic strength but not less than 85% of the
specified characteristic strength, and the average strength of
the group is not less than the specified characteristic strength
plus the standard deviation of the group.
MTECH CONSULTANTS
S1/21
Table 1.10
Initial current margin and required minimum cube strength less than 40 batches and 6 days
production.
Grade
Characteristic Strength
N/mm2
Half the Current
Margin
N/mm2
Required Minimum
Value of Mean of 4
cubes
N/mm2
7
7
2.3
9.3
10 10 3.3 13.3
15 15 5.0 20.0
20 20 7.5 27.5
25 25 7.5 32.5
30 30 7.5 37.5
35 35 7.5 42.5
40 40 7.5 47.5
MTECH CONSULTANTS
S1/22
Table 1.11
Current margin and required minimum cube strength for more than 40 batches (Produced
between 5 days to 6 months)
Grade
Characteristic
strength, C
N/mm2
Half current margin
N/mm2
* Required average
value of 4 cubes
= C + C'
N/mm2
C'
Minimum value
of C'
7
7
0.82S
1.17
7 + 0.82S,
or 8.17
10
10
0.82S
1.67
10 + 0.82S,
or 11.67
15
15
0.82S
2.50
15 + 0.82S,
or 17.50
20
20
0.82S
3.75
20 + 0.82S,
or 23.75
25
25
0.82S
3.75
25 + 0.82S,
or 28.75
30
30
0.82S
3.75
30 + 0.82S,
or 33.75
35
35
0.82S
3.75
35 + 0.82S,
or 38.75
40
40
0.82S
3.75
40 + 0.82S,
or 43.75
* The greater of the two alternative figures given for each grade shall be the minimum required
strength value.
(vii) The minimum value of C' given in Table 1.11 may be further reduced to half
by the Engineer if warranted by the results of more than 100 consecutive
batches of concrete.
MTECH CONSULTANTS
S1/23
(viii) The required minimum values given by Table 1.10 shall be considered an
interim result pending the subsequent production up to 40 batches and 6 days
production time.
(ix) If more than one cube in a group fails to meet the second requirement or if
the average strength of any group of four consecutive test cubes fails to meet
the first requirement, then all the concrete in all the batches represented by
all such cubes shall be deemed not to comply with the strength requirements.
For the purpose of this sub-clause the batches of concrete represented by a
group of four consecutive test cubes shall include the batches from which
samples were taken to make the first and the last cubes in the group of four
together with all the intervening batches.
(x) If only one cube result fails to meet the second requirement, then that result
may be considered to represent only the particular batch of concrete from
which that cube was taken provided the average strength of the group
satisfies the first requirement.
(xi) In the event of non-compliance with the testing plan, the Engineer
may order the Contractor to carry out tests on the hardened concrete in the
structure. These may include non-destructive methods or the taking of cored
samples. Non-destructive loading tests shall be carried out in accordance
with the requirements of BS 8110.
Alternatively, if the structure or part of the structure fails to fulfil any
requirement of the test, the Engineer may order replacement of the sub-
standard concrete or any other action he deems necessary. The entire cost of
testing and any remedial action shall be borne by the Contractor.
1.19 Transport
The concrete shall be transported from the mixer to the place of deposit in the works
as rapidly as practicable and by means which will prevent segregation of the material
or loss or contamination of ingredients. It shall be deposited as near as practicable in
the final position to avoid rehandling or flowing. The concrete shall be conveyed by
such vertical or inclined chutes that meet with the approval of the Engineer.
1.20 Placing of Concrete
(a) The concrete shall be placed in the positions and sequences indicated on the
Drawings, in the Specification or as directed by the Engineer. Except where
otherwise directed, concrete shall not be placed unless the Engineer is
present and has previously examined and approved the positioning, fixing
and condition of reinforcement and any other items to be embedded and the
cleanliness, alignment and suitability of the containing surfaces of
formwork.
MTECH CONSULTANTS
S1/24
(b) The maximum horizontal length of wall or floor in any one direction that
shall be poured in one operation is 8.0 metres. The construction of walls
and floor bays shall be carried out consecutively with a period of 7 days
allowed between adjacent pours except where waterstops are provided when
this period can be reduced.
(c) Alternatively, a gap of 600 mm wide shall be left between adjacent pours
and filled not earlier than 12 days after formation.
(d) Where kickers are required, they shall be at least 100 mm high and they shall
be constructed at the same time as the concrete on which they sit.
(e) The concrete shall be deposited as nearly as possible in its final position
without rehandling or segregation and in such a manner as to avoid
displacement of the reinforcement, other embedded items or formwork.
Wherever possible, bottom opening skips shall be used. Where chutes are
used to convey the concrete, their slopes shall not be such as to cause
segregation and suitable spouts or baffles shall be provided where necessary.
Concrete shall not be dropped through a greater height than 2 metres except
with the approval of the Engineer who may order the use of bankers and the
turning over of the deposited concrete by hand before being placed.
(f) Where pneumatic placers are used, the velocity of discharge shall be
regulated by suitable baffles or hoppers where necessary to prevent
segregation, or damage and distortion of the reinforcement, embedded items
and formwork, caused by impact.
(g) Concreting shall be carried out continuously between and up to
predetermined construction joints specified below in one sequence of
operation. In the case of slabs or beams designed to be monolithic with walls
or columns, at least one day lapse shall be allowed after casting of the wall
or column to allow for initial shrinkage before casting the beam or slab.
(h) The surface of the concrete shall be maintained reasonably level during
placing.
(j) A record shall be kept on the Works site of the time and date of placing the
concrete in each portion of the structure, and the reference numbers of the
test cubes pertaining to batches of concrete in particular parts of the
structure.
MTECH CONSULTANTS
S1/25
1.21 Placing Concrete in Water
The placing of concrete under water will not be permitted except where agreed by the
Engineer to be necessary. In placing concrete under water, it shall not be dropped
into the water but shall be carefully placed in position by enclosing it in bags, or by
means of bottom dumping bucket or tremie, or by continuous discharge through
pipes leading from the mixer. Whichever method is proposed to use, full details
shall first be submitted to the Engineer for his approval.
The surface of the concrete deposited under water shall be kept as nearly as possible
horizontal and no concrete shall be placed in running water or in water liable to
disturbance by pumping. Placing shall be such as to require the minimum amount of
spreading. Tamping to such an extent that segregation takes place shall be avoided.
Sufficient time shall be allowed for the concrete to set before it is subjected to any
form of loading and also to ensure that it shall suffer no damage from subsequent
pumping or de-watering operations.
1.22 Concreting in Adverse Weather
No concreting will be allowed to take place in the open during storms or heavy rains.
In places where such conditions are likely to occur, the Contractor is to arrange for
adequate protection of the materials, plant and formwork so that the work may
proceed under proper cover. Where strong winds are likely to be experienced,
additional precautions to ensure protection from driving rain and dust shall also be
provided. The Engineer may withhold approval of commencement of concreting
until he is satisfied that full and adequate arrangements have been made.
1.23 Concreting at Night or in the Dark
Where approval has been given to carry out concreting operations at night or in
places where daylight is excluded, the Contractor is to provide adequate lighting at
all points where mixing, transportation and placing of concrete are in progress.
1.24 No Partially Set Material to be used
All concrete and mortar must be placed and compacted within 20 minutes of its being
mixed. Unless otherwise approved, no partially set material shall be used in the work.
When truck-mixed concrete is used, water shall be added under supervision either at
the site or at the central batching plant as directed but, in no circumstances shall
water be added in transit.
MTECH CONSULTANTS
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1.25 Concreting in High Ambient Temperature
In hot weather and in places where the ambient shade temperature exceeds 32oC, the
Contractor shall take measures in the mixing, placing and curing of the concrete.
These shall be such as to ensure that the temperature of the mixed concrete at the
time of placing shall include the shading of aggregates, water supply tanks and
pipelines, from the direct rays of the sun, the spraying of aggregates with water,
cooling of the mix constituents, machinery reinforcement and moulds and the
reduction of transportation time to the minimum.
During placing, suitable means shall be provided to prevent premature stiffening of
the concrete placed in contact with hot surfaces. All concreting areas, formwork and
reinforcement shall be shielded from the direct rays of the sun and sprayed with
water when necessary.
1.26 Compaction of Concrete
The concrete shall be fully compacted throughout the full extent of the layer and
shall be brought up in level layers of such depth that each layer can be easily
incorporated with the layer below with the use of internal vibrators or by ramming. It
shall be thoroughly worked against formwork and around any reinforcement or
embedded items without displacing them.
Except where otherwise permitted by the Engineer, concrete shall, during placing,
be compacted by immersion vibrators having a frequency of at least 8,000
cycles/minute and of a type to be approved by the Engineer. The vibrators shall be
suitable for continuous operation. The vibrators shall be disposed in such a manner
that the whole of the mass under treatment shall be adequately compacted at a speed
commensurate with the supply of concrete from the mixers. They shall be operated
by workmen skilled in their use and whom shall be additional to the labourers
employed on placing and tamping the concrete. The internal vibrators shall be
inserted and withdrawn slowly and at a uniform pace of approximately 100 mm per
second.
Compaction shall be deemed to be completed when cement mortar appears in a circle
around the vibrator; over-vibration, leading to segregation of the mix must be
avoided. The internal vibrators shall be inserted at points judged by the areas of
mortar showing after compaction, with a certain allowance made for over-lapping,
and they shall not be allowed to come into contact with the formwork or the
reinforcement and shall be inserted at a distance of 75 mm from the former. The pan
vibrators shall be placed on the surface of the concrete which shall have previously
been tamped and levelled, leaving an allowance in height for the compaction, until
cement mortar appears under the pan. The vibrator shall then be lifted and placed on
the adjoining surface and this operations shall be repeated until the whole surface has
been compacted. Alternatively, a vibrating screed spanning the full width of the
surface may also be used.
Vibration is not to be applied directly, or through the reinforcement, to sections or
masses of concrete which have hardened or after the initial set has taken place.
Vibration must not be used to make the concrete flow in the formwork so as to cause
segregation.
MTECH CONSULTANTS
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1.27 Curing and Protection
Concrete shall be protected during the first stage of hardening from the harmful
effects of sunshine, drying winds, rain, running water or anything likely to
interfere with the process of setting. The protection shall be applied as soon as
practicable after completion of placing by covering the concrete surface with a layer
of sacking, canvas, hessian, straw mats or similar absorbent material or a layer of
sand, kept constantly moist by spraying with water as necessary for 7 days or such
periods as may be directed by the Engineer. Other methods of preventing the water
of hydration in the concrete from evaporating may be used if approved by the
Engineer. In the case of floor surfaces, the hessian shall not be applied until the
concrete is hard enough to resist marking.
Where formwork cannot be removed within 12 hours of placing, the concrete shall
be kept shaded from the direct rays of the sun and shall, where necessary, be
sprayed with water to minimise the loss of moisture from the concrete.
All work shall be protected from damage by shock or overload, including falling
earth and construction loads not computed for.
1.28 Concrete Cover
Concrete cover to members shall be provided as indicated on the Drawings. Where
not stated, concrete cover to main reinforcement shall not be less than that indicated
in Table 1.12:
The vertical distance between two horizontal main steel reinforcement bars or the
corresponding distance at right angles to two inclined main steel reinforcement, shall
not be less than 50 mm. This vertical distance shall be maintained by the use of
spacer bars placed between the reinforcement.
Table 1.12 Concrete Cover
Structural member
Concrete cover to main reinforcement
Solid slabs (above ground)
25 mm or diameter of bars, whichever is greater
Main columns 40 mm
Suspended ground floor slabs 35 mm
Beams and ribs (above ground) 35 mm or diameter of bars, whichever is greater
Ground beams 45 mm
Pile caps 50 mm
MTECH CONSULTANTS
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1.29 Construction Joints
The Contractor shall submit details of his proposals for construction joints and
concreting programme to the Engineer for approval. The Contractor is to allow for
working beyond the ordinary working hours where necessary in order that each
section of concrete may be completed without any lapse while the work is in hand.
The number of construction joints should be kept as few as possible consistent with
reasonable precautions against shrinkage.
All construction joints are to be formed square to work. Keyways are to be formed in
all horizontal and vertical construction joints except where ordered to be omitted by
the Engineer.
Where work is resumed on a surface which has set, the whole surface shall be
thoroughly roughened or scrabbled with suitable tools so that no smooth skin of
concrete that may be left from the previous work is visible. These roughened
surfaces shall be thoroughly cleaned by compressed air and water jets or other
approved means and brushed and watered immediately before depositing concrete. If
so ordered, roughened surface shall be covered with cement mortar (1:2 mix) prior to
placing the new concrete.
1.30 Joints in Concrete
Contraction joints where specified, shall be formed as deliberate planes of
discontinuity in the concrete structure. They shall be of a ‘key’ profile with or
without continuity in reinforcement.
Expansion joints shall be formed in the same way as contraction joints but in
addition, "flexcell" compressible filler as manufactured by Fosroc Expandite Pte Ltd
or similar approved shall be supplied and placed in the joints to provide freedom for
two adjacent concrete slabs or blocks to expand. The exposed edges of the joints
shall be sealed with an approved polysulphide rubber sealing compound to BS 4254.
Where a designed joint occurs in a water retaining structure, or where
otherwise ordered, the joint shall be made watertight by the provision of a
continuous waterstop strip of copper, rubber or plastic (such as Poly-Vinyl-Chloride,
P.V.C.) as specified, fixed across the joint where shown on the drawings. Special
care shall be taken to ensure that the concrete is well worked against the embedded
parts of the strip and is free from honeycombing. Precautions are to be taken to
protect any projecting portions of the strips from damage during the progress of the
Works and in the case of rubber and plastic, from light and heat.
In the case of copper waterstop where direct bituminous painting shall be applied to
the lips of the loop and the loop shall be fitted with a bituminous compound, these
applications shall be made before the strip is buried in the concrete.
MTECH CONSULTANTS
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1.31 Blinding Concrete
Several days before concrete is to be deposited on a foundation on the ground, a
blinding of concrete grade 15 of 75 mm minimum thickness, shall be placed over the
ground below the underside level of the reinforced concrete to form a hard even
surface on which to construct the latter. Where other details are indicated in the
Drawings, this Clause shall not apply.
1.32 Mass Concrete Backing to Masonry or Brickwork
Mass concrete backing to masonry of brick facing shall be mixed slightly wetter than
that mixed for placing against timber forms. Before any concrete is placed, the
mortar joints in the facework shall have thoroughly hardened, and the back of the
facing must be thoroughly wetted. The concrete shall be carefully tamped round any
ties or bond stones, and mortar from the concrete shall be carefully worked into the
open joints in the back of the facework.
1.33 Formwork
(a) General
The formwork shall be constructed of sound, well-seasoned timber or other
approved material of such quality and strength as will ensure complete
rigidity throughout the placing, ramming, vibration and setting of the
concrete. It shall be sufficiently tight to prevent loss of liquid from the
concrete.
Where formwork is not provided with special lining as specified in Clause
(b) below, the faces in contact with concrete shall be planed smooth, true to
alignment and free from surface imperfections and the joints between boards
shall be tongued and grooved or caulked with tight fitting fillets recessed into
adjacent boards and covering the joint. Internal ties or struts shall be of
metal and capable of removal without injury to the concrete. No part of any
metal tie or spacer remaining permanently embedded in the concrete shall be
nearer than 50 mm to the finished surface of the concrete. Construction
details shall be arranged to permit easy removal, and wedges and bolts shall
be employed whenever possible in preference to nails.
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(b) Cleaning and Treatment of Forms
Before concrete is deposited, the forms shall be thoroughly cleaned and freed
from sawdust shavings, dust, mud or other debris by hosing with clean water.
Temporary openings shall be provided in the forms to drain away the water
and rubbish. Unless otherwise directed by the Engineer, the inside surface of
forms shall, before placing of the reinforcement, be coated with an approved
mould oil or other release agent, care being taken at all times thereafter to
keep the reinforcement free from any such material. There shall be no excess
coating material in the form prior to concreting. All formwork shall be
inspected by the Engineer after preparation and immediately prior to
depositing concrete and no concrete shall be deposited until approval of the
formwork has been obtained from the Engineer.
(c) Removal of Formwork
Formwork shall be removed without such shock or vibration as would
damage the concrete. The minimum striking times shall be as listed in Table
1.13 below. The times are given in days, where a day is to be of 24 hours
duration.
Table 1.13 Minimum striking times
Location of forms removed
Minimum Striking Times for O.P.C.
( Ordinary Portland Cement ) concrete (days)
Slabs soffits (structural props left in)
5
Beam sides (greater than 1200 mm lift)
(less than 1200 mm lift)
3
1
Beam soffits (structural props left in)
6
Slab structural props
10
Beam structural props
21
Columns and walls (unloaded)
3
The foregoing Table is given as a guide for Ordinary Portland Cement (OPC). The
Engineer may at his discretion alter the above times if he considers such adjustment
to be necessary.
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1.34 Forms for Exposed Concrete Surfaces
Forms for all permanently visible concrete surfaces shall be such as to ensure that
surface is of the correct shape, line and dimensions. Where rough formwork is
specified, no surface irregularities greater than 10 mm shall be allowed and, in the
case of reinforced concrete, the full cover to steel shall be maintained. Where
wrought formwork is specified, the forms shall be such as to produce a smooth and
even surface free from perceptible irregularities, and tongued and grooved; planed
boards or plywood or steel forms shall have their joints flush with the surface. The
full cover to reinforcement steel shall be maintained. The Contractor shall make due
allowance for the renewal and /or repair of shuttering for which more than one use is
intended.
1.35 Forms for Non-exposed Concrete Surfaces
Where the finished surface of concrete is not to be permanently exposed, the forms
may be constructed of plain, butt-jointed sawn timber unless otherwise directed by
the Engineer. In mass concrete, surface irregularities may be permitted but in
reinforced concrete construction, the surface shall be true and the full cover to the
reinforcement shall be maintained at all points.
1.36 Surface Defects
As soon as the formwork has been removed, but after inspection by the Engineer,
honey-combing or small holes in faces shall be filled with cement mortar composed
of equal parts of Portland Cement and sand. However, if in the Engineer's opinion,
any defects cannot be made good by touching up, he may order the replacement of
the work, which will be at the Contractor's own cost.
1.37 Openings in Reinforced Concrete
All necessary openings for pipes, fittings outlets, etc., shall be formed and the corners
or edges trimmed with high tensile bars to approval.
1.38 Fixings and Cavities in Concrete
The Contractor shall ascertain from the drawings or from sub-Contractors or from
elsewhere, particulars of all bolt and other fixings, and of all openings, holes,
pockets, chases, recesses and other cavities so that before the placing of the
concrete, all bolts, boxes and fixings shall be in place. No holes shall be cut after
the concrete has been placed without express authorisation from the Engineer.
MTECH CONSULTANTS
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1.39 Concrete Finishes
(a) General
The faces of concrete work shall have the finishes indicated on the Drawings
if these are provided. The finished surface of all concrete work shall be
sound, solid and free from honeycombing, protuberances and blemishes. No
plastering of imperfect concrete faces will be allowed and any concrete that is
defective in any way is to be cut out and replaced to such depths and be made
good in such manner as the Engineer may direct at the Contractor's own
expense. The cavities left by formwork fixing devices are to be made good by
completely filling the hole with mortar, which shall be such as to dry out with
the same colour as the adjacent concrete.
(b) Fine Finish
When a fine finish is specified, the surface of the concrete shall, immediately
following the removal of the forms, be wire brushed to remove any surface
imperfections or irregularities. It shall then be well brushed with water and
rubbed down to a smooth finish by means of a carborundum block. Where
directed, the rubbing down shall be preceded by the application of a Portland
Cement wash and the surface thus treated shall be carefully protected from
rapid drying out by suitable means.
(c) Concrete Surfaces without Formwork
(i) Where, on an upward facing horizontal or near horizontal surface
which does not require formwork, no particular finish is called for,
the surface shall be that produced by the proper placing and
compaction operations without further labours.
(ii) Where a 'fair surface' is specified, it shall be obtained by screeding.
This shall be done immediately after compaction of the concrete, by
the slicing and tamping action of a screed board running at the top
edges of the formwork, or on accurately set screeding guides, to give
a dense concrete skin, true to line and level.
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(iii) Where a 'fine surface' is specified, it shall be obtained by first
screeding the concrete as described in the preceding sub-clause then
leaving it until the concrete has stiffened and the film moisture has
disappeared. Floating shall then be applied with a steel or wooden
float to produce a 'glossy' surface or a 'sand paper' surface as
required. Working should be kept to a minimum compatible with a
good finish. The surface shall be true to the required profile to fine
tolerance. Wherever necessary, a properly constructed overhead
cover shall be erected before the work is commenced to prevent the
finished surface from being marked by raindrops or dripping water.
(d) Workmen
The finish to the exposed concrete surfaces shall only be carried out
by skilled workmen experienced in this class of work. The Engineer
may order the removal of any workman whom he may consider
insufficiently experienced or skilled for this class of work and require
the substitution with workmen of the required standard.
(e) ‘WireBrushed’ Finish
Immediately after removal of the forms the surface of the concrete
shall be well scrubbed down by means of stiff wire brushes and water
to remove the cement from the surface and expose the aggregate.
(f) ‘Bush Hammered’ Finish
Not less than 3 weeks (for Ordinary Portland Cement concrete) after
the concrete has been placed the exposed surface shall be bush-
hammered to remove the cement from the surface and expose the
aggregate. Bush hammers shall be of an approved type, and they shall
be worked to within 12 mm of all corners and arises, the treatment of
the remaining 12 mm borders being hand finished similar to that of
the adjoining bush-hammering. Bush hammers shall be kept
perpendicular to the surface being worked and care shall be taken to
ensure that only the surface mortar and the irregular projections of the
aggregate are removed without any fracturing or loosening of the
portions left embedded. As the bush-hammering is completed, the
surface so treated shall be washed with water and scrubbed down with
a stiff brush. All finished surfaces shall be of an even and uniform
appearance with the exposed aggregate clean and free from film.
MTECH CONSULTANTS
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(g) Specimen Panels of Concrete
Where required by the Engineer, the Contractor shall construct and
treat specimen panels of concrete to the required finish, in order to
satisfy the Engineer as to the suitability and efficiency of the
proposed method of treatment.
1.40 Surface Tolerances
The acceptable tolerances on concrete surfaces measured in millimetres shall be as
listed in Table 1.14.
Table 1.14 Acceptable tolerance on concrete surfaces.
Type of
structure
Type of irregularity
Sawn
Formwor
k
Faced
formwork
Tamped
formwork
Float
Finish
Buried
concrete
Departure in alignment
and grade
+50
-10
-
+10
-
Variations in cross
sectional dimensions
+10
-5
-
+10
-5
-
Deviation from
alignment checked
against a 3m straight
edge
+10
-
+10
-
Exposed
concrete and
internal
surfaces of
sewer culverts
Departure in alignment
and grade
-
+10
+10
+5
Variations in cross
sectional dimensions
-
+10
-5
- +10
-5
Deviation from
alignment checked
against a 3m straight
edge
-
+5
+5
+5
MTECH CONSULTANTS
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1.41 Tests on the Structures
The Engineer shall instruct the Contractor to make a loading test on the works or any
part thereof if in the Engineer's opinion, such a test is necessary.
If the test so instructed to be made solely or in part for the reason that the
site- made concrete cubes fail to attain the specified strength, the test shall be made at
the Contractor's own expense. If the test instructed to be carried out is because of
one or more circumstances attributable to alleged negligence on the part of the
Contractor, the Contractor shall be reimbursed for the cost of the test if the result
thereof is satisfactory.
If the test be instructed to be made for any reason other than the foregoing, the
Contractor shall make the test and shall be reimbursed for all costs relating thereto,
irrespective of the results of the tests.
For the purpose of testing floors, roofs and similar structures and their
supports, the test load shall be equivalent to one-and-a-quarter times the live load for
which the Works or part thereof to be tested has been designed. The test load shall
not be applied within twenty-eight days of the completion of placing of the concrete
in the part of the Works to be tested, and the latter shall be unsupported during the
test by the shuttering or other non-permanent support. The test shall be made as
instructed.
For test on a floor, roof or similar construction, the result shall be deemed to be
satisfactory if upon removal of the load the residual deflection does not exceed one
quarter of the maximum deflection occurring during the second test.
If the result of the test is not satisfactory, the Engineer shall instruct that the part of
the Works concerned shall be taken down or cut out and reconstructed to comply
with this Specification, or that other measures shall be taken to make the Works
secure. If in accordance with this Specification the Contractor is liable to conduct the
test at his own cost, he shall also at his own cost, take down or cut out and
reconstruct the defective work or shall execute remedial measures as instructed.
1.42 Preparation of Ground below Permanent Construction
Plain concrete in foundations or site concrete shall be placed in direct contact with
the bottom of the excavation, the concrete being deposited in such a manner as not to
be mixed with the earth. Alternatively, when directed by the Engineer or shown on
drawings, hardcore and/or sand blinding shall be used, or a layer of building paperis
specified.
MTECH CONSULTANTS
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1.43 Temperature Control ( For structural slab or member with thickness exceeding 1.2m)
(a) The contractor shall take steps to limit the temperature of the concrete placed as
follows
(i) Not exceeding 32°C at the time of placing.
(ii) Not exceeding 78°C during hydration at any time up to 14 days after
concreting.
(iii) Not exceeding 20°C as a difference between the most exposed face of the
concrete and the mid-depth of the pour after concreting.
Concrete which fails to comply with (i) shall not be placed in slab. Concrete which
fails to comply with (ii) and (iii) anywhere in their length/volume shall be considered
as defective work.
A minimum of four (4) sets of thermo-couples consisting of 5 Nos. per set for
recording concrete temperature shall be placed in advance in panel to cast. The
thermo-couple shall be secured in positions by non-conductive material such as pvc
and kept from coming into contact with steel reinforcement bars. Each set of thermo-
couples is to be arranged in vertical row with the topmost and bottommost thermo-
couples being placed within a cover of 25 mm. One thermo-couple shall be located
at mid-depth of the slab and the remaining two placed at 1/4 and 3/4 depth of the slab
thickness respectively.
The concrete temperature shall be recorded at intervals not exceeding two (2) hours
for the first 24 hours and thereafter at 6 hours interval or at such other intervals as
maybe required by the Engineers for a minimum period of fourteen (14) days or until
a differential temperature of 10°C or less is attained.
The Contractor shall submit at the time of tender, the methods he proposes to use to
achieve the concrete temperature limits as stated above.
Protection shall be applied as soon as practicable after completion of placing by a
layer of waterproof fabric keep in contact with the concrete.
(b) In order to comply with temperature limitation requirements, advantage shall
be taken of the insulation value of any timber formwork that may be in use
by allowing it to remain for sufficient time to ensure the peak of temperature
is passed before removal. Slab surfaces should be protected as soon as
practicable after the initial set has taken place by covering the surface with a
0.15mm thick polythene sheet with watertight joints upon which 100 mm
thick polythene foam boards are placed.
MTECH CONSULTANTS
S1/37
(c) Test Blocks for Testing Thermal Characteristics of Concrete
Before placing concrete, the Contractor shall ascertain the thermal characteristics of
the cement and aggregates to be used from which he shall calculate the likely
maximum temperature of the concrete during hydration. The Contractor shall submit
the calculations to the Engineers for approval. The Contractor shall then construct
two test blocks of 1.2m x 1.2m x 2.0m (D) each. The blocks shall be reinforced on
the top and bottom face with 25mm dia. high yield reinforcing bars at 200 mm in
each direction. The clear cover to the bars shall be 50 mm.
The materials used in making concrete for the test blocks, reinforcement, formwork
and materials used for protecting the top surfaces of the test blocks during curing
shall be those intended for use in placing the slab concrete. The test blocks shall be
cooled and insulated in the same manner as the member to be cast.
The temperature of the concrete at the time of placing shall not exceed 32 degrees
Celcius. Thermometers shall be installed in the concrete near to the surface at the
centre of each face and one shall be placed centrally in the block. Temperatures shall
be recorded at initially two hourly intervals for a period of 48 hours and thereafter at
eight hourly interval for a further period of at least 12 days for each block.
Six (6) 150 mm test cubes shall be prepared during the placement of concrete for
each block with two for testing at 7 days and four for testing at 28 days.
The test blocks shall be examined at regular intervals for potential cracks and a
careful note shall be made of any cracks found during the period leading to the
testing of the test cubes.
The concrete mix shall be considered satisfactory if for each block the following
conditions are met : -
(i) The average strength of the four test cubes at 28 days exceeds that specified
for preliminary and trial mix tests by at least 5 N/mm².
(ii) The maximum temperature during hydration does not exceed 78 degrees.
Celsius and the difference in temperature between any face of the test block
and its centre does not exceed 20°C at any time.
(iii) The nature of any cracks appearing in the test block is such that, in the
opinion of the Engineer, the cracks do not constitute a potential source of
harm if they were to occur in the concrete for the permanent works.
If condition (i) above for cube strength is not fulfilled the Contractor shall redesign
the concrete mix, construct further test blocks and repeat the testing as specified.
MTECH CONSULTANTS
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If condition (ii) above is not fulfilled or if under condition (iii) the Engineer is of the
opinion that the cracks as noted are potentially harmful the Contractor shall propose
additional measures to comply with conditions (ii) and (iii) at his own cost.
If the Engineer so requires the Contractor shall construct further test blocks to
demonstrate the efficacy of the measures which are to be incorporated before placing
concrete in slab.
(d) Casting of slab using the method of temperature control
Prior to the casting of slab, the Contractor shall submit method statements relating to
the following items for the approval of the Engineer: -
(i) Details and results of the temperature trials.
(ii) Mix proportions of the concrete mix using minimum cement content or
replacement of cement with silica fume including all admixtures used to
achieve a slump of not less than 200 mm with minimum segregation and
bleeding and the specified concrete placing temperature.
(iii) Plant, equipment (including standby equipment) and manpower that are
required for each pour.
(iv) Sources of supply of concrete and alternative sources of supply of these
items in the event of total breakdown.
(v) Time and duration of each pour.
(vi) Traffic flow pattern of concrete supply trucks within the Site.
(vii) Concrete placing and compaction.
(viii) Progressive removal of bleeding water from the wet concrete.
(ix) Thermal insulation to formed and exposed surfaces.
(x) Temperature monitoring and record, including layout and setting out of
thermo-couples and the type of electronic thermometer capable of converting
directly into degrees centigrade the potential difference generated by the
thermo-couples.
(xi) Curing.
(xii) Layout and preparation of construction joints. The construction sequence
should be planned to minimise trapped bays (i.e. bay which has adjacent
sides or two opposite sides cast against massive hardened concrete with
continuous reinforcement across each interface).
MTECH CONSULTANTS
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(xiii) Measures to be taken in emergency situations (e.g. rain).
(xiv) Other information relating to the casting of the slab which may be required
by the Engineer.
1.44 Precast Concrete
(a) General
The concrete as cast in one piece shall be placed in one operation. No pieces shall be
removed from the mould or erected until sufficiently matured to ensure that no
damage shall be done to the piece. A piece shall be suspended or supported only at
the points described on the working drawings or elsewhere. A piece that is cracked or
damaged during, before or after erection shall be removed from the works from the
works and replaced by the Contractor at his own expense. Pieces shall be bedded or
fixed in their permanent positions as instructed.
(b) Materials
All precast concrete and revetment slabs shall satisfy BS 368 especially Tables 2 &
3.
All precast pipes shall conform to SS 183.
All precast kerbs and channels shall satisfy BS 340.
MTECH CONSULTANTS
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SECTION 2 - STRUCTURAL STEELWORK AND METALWORK
1. STRUCTURAL STEELWORK
1) GENERAL
1.1 Definitions
(a) Shop Drawings
These refer to drawings showing all necessary information to fabricate and erect the
structural steelwork and structural steel decking including drawings showing the
dimensional layout of the steel structure and which correlate the piece markings with
the location in the structure.
(b) Quality Assurance/Quality Control
The specification describes an acceptable level of quality to be achieved by the
Contractor, and it describes the tests that the Contractor shall carry out to
demonstrate that he has achieved the required quality.
(c) Independent Testing Agency
In addition, an independent organisation (if required under the project) separately
appointed by the Employer and known as the Independent Testing Agency (ITA),
shall carry out certain tasks to ensure that:
i) The Contractor's proposed methods of working are likely to produce
acceptable work.
ii) Finished items and assemblies conform with the Specification.
The duties of the ITA include the carrying out of non-destructive testing in addition
to that carried out by the Contractor.
1.2 Substitutions
No substitutions to the Contract Specification or Contract Drawings may be made
without approval.
1.3 Commencement of The Work
No item of work shall be commenced until the results of any related preliminary test
required by the Contract Specification have been approved.
1.4 Code of Practice
Comply with BS 5950 and this section of the Contract Specification. In cases of
conflict, the more stringent will take precedence.
MTECH CONSULTANTS
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1.5 Connection Details
Design and detail those connections which are not shown on the Contract Drawings.
The type of joint is to follow the form of the typical details shown on the Contract
Drawings and is to be designed to carry loads which shall be specified. All details
designed by the Contractor are to be substantiated by full calculations certified by a
Professional Engineer registered in Singapore.
1.6 Temporary Works
Design, fabricate, erect and remove all temporary work. The Contractor shall engage
a Professional Engineer registered in Singapore for the design and supervision of the
erection for all temporary works and he shall be responsible for ensuring the safety
and stability of the structure during all stages of the construction.
1.7 Construction Information
(a) Fabrication
Provide the following information at least 8 weeks before commencing
fabrication.
i) Complete and coordinated Shop Drawings.
ii) Calculations to substantiate connections detailed
by the Contractor.
iii) Detailed method statements for fabrication.
iv) Details of welding procedures in accordance with
BS 5135 for all welds, including tack and sealing welds.
v) Details of proposed shop inspection system and non-
destructive testing arrangements.
(b) Erection
Provide the following information at least 8 weeks before commencing
erection.
i) Detailed method statement for erection, including type of crainage.
ii) Detailed drawings and calculations for all temporary works.
iii) Detailed of proposed site inspection system.
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(c) As-Built Drawings
Provide as-built drawings which show the work as finally fabricated and
erected.
1.8 Programme
(a) Detailed Programme
Provide a detailed programme to show the planned timing of the various
items of work to be done, including:
i) Preparation and submission of construction information.
ii) Order and delivery of materials
iii) Fabrication
iv) Application of protective coatings
v) Transport to site.
vi) Erection
(b) Inspection and Testing
Provide a detail programme and include in the programme the necessary time
for all procedural trials, inspection and testing, and trial assemblies if
required. The Contractor shall also make allowance for time required by ITA
to carry out cross-checking of Contractor's testing. The average rate of ITA
testing may be assumed to be one ITA test for every 20 Contractor tests.
(c) Progress
Arrange the programme so that actual progress can be monitored against
each item.
2) QUALITY CONTROL
Provide a Quality Manual to the satisfaction of the Engineer and as laid down to the
requirements of Quality Assurance Programs
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3) MATERIALS
3.1 Steelwork
(a) The Universal Section Steels and Hollow Section Steels to be used shall be of
the best quality and conform to the respective British Standards Specification for
such material.
(b) Every section shall be straight and true to its profile.
(c) Where a section is to be cut to an exact length, it shall be cold sawn to within
+3.2 mm of that length.
3.2 Splicing
Except where specifically instructed by the Engineer in writing, every section shall
be in one length throughout. If and when extension of particular sections are so
instructed, the extension piece shall be in a single length to be determined by the
Engineer and not made up of two or more short pieces. The Contractor shall
fabricate the splice by welding in accordance with a detail drawing to be provided by
the Engineer. Such joint will be designed to transmit the full strength of the steel
section in shear, bending and bearing.
3.3 Bolts, Nuts and Washers
Mild steel bolts and nuts shall comply with the requirements of BS 5950 and either
BS 916 or BS 2708 or BS 4190.
Structural quality high tensile steel bolts and nuts shall be manufactured from
material as specified in BS 5950 and BS 4360 Grade 50B.
Special quality high tensile steel bolts and nuts shall comply with the requirements of
BS 5950 and either BS 1768 or BS 1083 or BS 3692.
High strength friction grip bolts, nuts and washers shall comply with the
requirements of BS 4395 and BS 4604.
Plain and tapered washers, other than for high strength friction grip bolts, shall
comply with the requirements of BS 5950 and BS 4320.
High strength friction grip bolts are to be of the load indicating type. All bolts, nuts
and washers shall be cadmium plated to a minimum thickness of 0.005 mm. Load
indicating washers shall be standardised.
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4) WELDING
Welding shall be carried out in accordance with BS 5950, BS 856, BS 2642 and BS
639 as applicable for the type of steel used, by an electric arc process using
equipment of adequate capacity for the conditions of the work.
All welding shall be carried out by fully trained and experienced welders. In this
connection, the Engineer may request the production of Welders Test Certificates.
Surfaces to be welded shall be free from loose scale, rust, grease, paint or other
deleterious material that might impair the quality of the weld.
Welding should be done in the workshop wherever possible.
5) PLANT AND EQUIPMENT
The suitability and capacity of slings, lifting appliances and blocking and of all other
plant and equipment used for erection shall be to the satisfaction of the Engineer.
6) SETTING OUT
The positioning and levelling of all steelwork, the plumbing of stanchions shall be in
accordance with the approved drawings and to the satisfaction of the Engineer.
7) SAFETY DURING ERECTION OF SHORING
During erection, the work shall be securely bolted or otherwise fastened and if
necessary, temporarily braced to provide safety for all erection stresses and
conditions, including those due to erection equipment and its operation. Neither
permanent bolting nor welding shall be done until proper alignment has been
obtained.
8) FABRICATION
As much as possible of the work shall be fabricated in the Specialist Fabricator's
workshop. Four clear days' notice shall be given to the Engineer of fabricated work
being ready for inspection at the workshop.
The steelwork shall be fabricated to a pre-camber so that the dimensions required on
completion of erection are obtained. The instructions for forming the pre-camber that
are given on the Drawings shall be followed.
All parts such as main stanchion caps and bases and butt joints shall be
accurately machined so that the whole areas of the section shall make the required
contact. The bases shall be truly at right angles to the axes of the stanchions in all
planes.
The ends of all joists, beams and girders shall be truly square where required, and
joist flanges shall be neatly cut away and notched where necessary; the notches
being kept as small as possible and well radiused.
Cutting may be effected by shearing, cropping or sawing. Gas cutting may only be
used when specifically authorised in writing by the Engineer. The edges of all
MTECH CONSULTANTS
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plates shall be perfectly straight and fair throughout. Sheared members shall be free
from distortion and shall have the edges dressed to a neat and workmanlike finish.
Except where suitable templates are used, holes through more than one
thickness of material shall be drilled after the members are assembled and tightly
clamped together. If the holes are punched separately before assembly, the holes
shall be punched 4 mm less in diameter than the required size and reamed after
assembly to the full diameter. The maximum thickness of materials punched shall
not be greater than 16 mm.
All members shall be straight, free from twists, cracks, flaws, laminations,
rough, jagged and imperfect edges and other defects.
Holes for bolts shall not be formed by a gas cutting process, except with specific
approval from the Engineer.
9) HIGH STRENGTH FRICTION GRIP BOLTS
High strength friction grip bolts to BS 4395 shall be used in accordance with BS
4604 Part 1 with modifications and additions given below.
All bolts shall be provided with hardened steel washers under both head and nut.
The washers shall be suitably tapered where the angle between the bolt axis
and the steel bearing surface is outside the limit of 90o + 1o.
Each bolt shall be tightened to its specified proof load and the required induced
tension shall be indicated by the compression of protrusions either on the bolt head
or on a washer. Where the load is indicated by protrusion or a washer, such
washer may replace a flat washer under the bolt head but in places where it is
necessary to place the indicating washer under the nut then an additional facing
washer shall be supplied, suitably heat-treated to the same hardness as the bolt.
Before any bolt of a group is finally tightened, all bolts of the group shall be part
tightened in the correct sequence by applying a bedding torque as given in
Table 1 below. After the bedding torque has been applied to each bolt, the bolts
shall be tightened in the correct sequence until the gap under the load indicating bolt
head or washer has been reduced to a dimension determined by the Engineer. If for
any reason a bolt is slackened or removed after full tightening, it must be replaced by
a new bolt.
MTECH CONSULTANTS
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Table 1 Bedding torque for high strength friction grip bolt
Preliminary tightening of nuts
Nominal diameter of bolt Bedding torque (Nm)
(mm) Minimum Maximum
20 122 244
22 170 340
25 237 474
28 373 746
32 530 1060
10) HOLDING-DOWN BOLTS AND OTHER FIXINGS.
Holding down bolts and other fixings are to be set out accurately, with templates
provided if necessary, by the Contractor in accordance with the Engineer's
and Specialist's drawings, and when cast in shall be protected from any damage or
deterioration.
Holding down bolts shall be cast in to the dimensions shown on the Engineer's
drawings, and the Contractor shall ensure that the projecting ends of the bolts have
freedom for horizontal movement within the hole. The projecting ends of bolts shall
be well greased and wrapped in sacking which shall remain in position until the
commencement of steelwork erection.
Prior to the delivery of steelwork for erection, the Contractor shall check concrete
bases or other seating for steelwork in respect of level, setting out, projection and
full degree of adjustment of holding down bolts or other fixings and ensure they
are in accordance with the Engineer's and/or Contractor's drawings.
The Contractor shall remedy any discrepancies or inaccuracies to the satisfaction of
the Engineer. No modification of the steelwork or fixings, bending of holding down
bolts, or the use of an excessive number of washers to accommodate errors in
position and projection of bolts or fixings shall be made except with the written
permission of the Engineer.
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11) GROUTING OF STEEL BASES AND CONCRETE ENCASURE OF
STRUCTURAL STEELWORK.
After final levelling and alignment of the steelwork, grouting and encasing shall be
carried out by the Contractor as follows:
(a) In all cases the grouting space shall be thoroughly clean and temporary
shuttering shall be provided if necessary to enable the requisite pressure head
to be sustained.
(b) Grouting of stanchion bases and bearings of beams and girders.
(c) Grouting shall be laid in strict accordance with the manufacturers instructions
and shall be of a non-shrink type or Engineer approved equivalent.
12) PROTECTION OF STEELWORK AGAINST CORROSION
12.1 General
Except as otherwise specified, the relevant clauses of the British Code of
Practice, CP 2008 : 'Protection of Iron and Steel Structures from Corrosion'
shall apply.
On the placing of this Contract and well before the commencement of the
protective coating of any steel, there shall be consultations between the
Engineer and the Contractor to agree inspection methods, tools and timing.
All shop treatment shall be carried out in an approved, weatherproof
structure under dry, clean conditions. Open fires, or other heating methods
producing sulphur dioxide shall not be used.
Notwithstanding the 36-hour curing periods specified herein, no treatment
shall be applied until the Engineer is satisfied that the surface is clean and
dry, and that any previous treatment is satisfactory and has hardened
adequately. When a surface has been approved, it shall be painted
immediately.
All paints are to be applied by techniques to produce a surface of uniform
colour and texture. Particular importance shall be paid to the works finishing
coat. All tools, solvents and plant used shall be such as to secure the best
possible results, and shall be maintained in good condition both in use and in
storage. Solvents used for the removal of oil, grease and dirt shall be non-
injurious to both metal and paint, and any excess shall be completely cleaned
off immediately after use.
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Every subsequent coat applied to any surface shall be of a hue different from
that preceding such that the coverage of each coat is easily visible.
Throughout the protective treatment, transport, site storage and erection, the
lifting and handling methods shall be such as to secure the absolute
minimium of damage to paint work. Such damage as does occur shall be
made good when so directed by the Engineer, to his entire satisfaction.
Touching up to the correct thickness must be carefully carried out to avoid
high spots in the system.
12.2 Preparation of surfaces to receive paint
CANCELLED
12.3 Treatment of Surfaces
CANCELLED
MTECH CONSULTANTS
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12.4 Treatment to be carried out on Site
Prior to erection, all steelwork is to be thoroughly washed down and cleaned.
Any handling or transit damage to the shop treatment and any damage caused
by erection shall be made good as soon as possible.
Damaged areas of paint work shall be cleaned to bare metal and the edges of
the undamaged paint levelled with sand paper. The full specified painting
system shall then be re-applied and the new paint shall overlap the existing
paint by at least 50 mm all round the affected part.
All contact surfaces shall be thoroughly wire brushed and cleaned of all
foreign matter immediately prior to being brought together. Special care
shall be taken to remove all oil, grease, paint, etc., from surfaces joined by
friction grip bolts.
After tightening, bolt heads, nuts and washers shall be cleaned and externally
exposed surfaces painted with two coats of primer and one coat of finishing
enamel.
Surfaces to be encased in concrete shall be thoroughly cleaned of all loose
paint and rust, oil and grease immediately prior to concreting and left
untreated, except that a strip 30 mm wide from each edge shall be treated as
for the adjacent steelwork.
MTECH CONSULTANTS
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12.5 Standard of finish
The Contractor shall ensure that the whole of the paint work is in a good,
clean condition, and of uniform appearance on completion of the Contract.
Unless otherwise agreed by the Engineer, each coat of paint shall be applied
by the method specified and recommended by the manufacturer to produce a
continuous film of paint of uniform and even thickness in the dry condition
of the applied paint. In the case where no such recommendation has been
given, the Contractor shall refer to the Engineer for the approved method of
application.
The total dry paint film thickness of the various systems shall not be less than
the specified values. The paint film thickness shall be measured when dry,
using Elcometer or other instruments approved by the Engineer.
In order to obtain dry film thickness specified, the contractor shall ensure
that the coverage rate given by the paint manufacturer will enable this
thickness to be attained.
12.6 Storage of Painted Steelwork
Painted fabricated steelwork which is to be stored prior to erection shall be
laid out or stacked in an orderly manner that will ensure that no pools of
water or dirt can accumulate on the surfaces. Suitable packings shall be laid
between the layers of stacked materials. Where a cover is provided, it shall
be well ventilated. Any steelwork on which the application of the shop
treatment has commenced, shall be fully protected from external atmospheric
conditions, until completion of the system and curing period previously
specified.
12.7 Paint
All paints shall be obtained from suppliers approved by the Engineer. Unless
otherwise agreed by the Engineer, all paints forming part of any one painting
system shall be obtained from the same source. Paint shall be supplied in
sealed containers of a capacity, unless otherwise approved, of not more than
one gallon, and shall be used in strict rotation. Samples of paint from each
making batch shall be submitted to a laboratory for tests as may be required
by the Engineer.
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12.8 Paint Removers
Water rinseable and solvent rinseable paint removers shall comply with the
requirements of BS 3761.
Certificates that the material has complied with the foregoing tests shall be
supplied by the manufacturers.
13) TESTING
13.1 Testing of Steel Structures
All tests on structural steel shall be carried out in accordance with Singapore
Standard CP8:1978 "Use of Manual Metal-Arc Welding in Steel Building
Construction" and BS 4360.
13.2 Non-destructive Testing
The Contractor shall afford all facilities for the inspection of the work at all
stages by the Engineer or his inspecting Engineers at the Contractor's works
and those of his subcontractors. All works shall be subject to inspection
before shipment to the site. Any work found defective or which is not in
accordance with the drawings or specifications shall be rejected and shall at
once be made good or replaced where deemed necessary by the Engineer.
The Contractor shall give such reasonable notice to the Engineer or his
inspecting Engineer of the progress of the work as will enable the inspection,
examination and testing as required.
Samples of materials and workmanship to be employed in the works may be
called for at any time by the Engineer. Cost of providing and obtaining all
samples shall be deemed to be included in the rates entered in the Breakdown
Cost of Works.
The Contractor shall arrange for all materials to be tested at the
manufacturer's works and when required in the presence of the Engineer's
inspector. When materials are obtained from supplier's stock, the Contractor
shall, by means of identification marks stamped on the materials together
with the manufacturer's test certificate, show that such materials comply with
the requirements specified herein.
The Engineer reserves the right to require an independent analysis and tests
on the materials by an approved PSB accredited laboratory selected by him.
For this purpose the Engineer's inspector will take drilling for analysis and
have pieces cut out side by side with pieces subjected to test in the
workshops, in order that a comparison can be made. Should the result of any
independent analysis or test be unsatisfactory, the material represented will
be rejected.
MTECH CONSULTANTS
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The cost of all tests made by manufacturers or made at the works of the
Contractor or his subcontractors or at the site shall be deemed to be included
in the rates entered in the Breakdown Cost of Works. The cost of
independent testing ordered by the Engineer shall be charged against the
provisional sum in the Breakdown Cost of Works, except for tests on
materials which are rejected, which shall be borne by the Contractor.
2 METALWORK
2.1 Galvanised Steel
a) All sections to be made from steel plates shall be in accordance with BS
4360, rods and bars are to be in accordance with BS 1449 Part 1 and 2 of low
carbon galvanised steel. Small steel angles, tees and channels shall be of cold
rolled section complying with BS 2994.
b) Unless otherwise stated, all steel sections, channels, angles, brackets, plates,
chains, trusses, pipes, frames, etc. including fasteners shall be hot-dip
galvanised. Any damaged/cut/welded parts shall be treated with two coats of
appropriate primers and zinc based compatible paint or equivalent
respectively.
c) All galvanised steel bolts used shall include heads, nuts and washers.
2.2 Stainless Steel balustrades and handrails
Supply and install stainless steel pipe balustrades and handrails consisting of
balusters, handrails, horizontal intermediate and bottom rails, the whole welded
together and including fixing to brick or concrete wall and concrete kerb with
stainless steel plates, brackets, etc.
2.3 Galvanised, Steel Channels, Angles, Brackets, Plates, Etc.
Supply and fix all galvanised steel hollow sections, channels, angles, brackets
purlins, flashings, plates, etc.
2.4 Galvanised Steel Framings
Supply and fix galvanised steel framings consisting of hollow sections, channels,
angles, brackets, plates, etc. with welded or bolted connections.
MTECH CONSULTANTS
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2.5 Galvanised Steel Grilles
Supply and fix galvanised steel grilles painted with two coats of zinc chromate
primer, one undercoat and spray painted with two finishing coats of enamel paint.
2.6 Galvanised Steel Mesh
Supply and fix polyester powder coated expanded galvanised steel mesh complete
with galvanised steel frame.
2.7 Galvanised Steel CurtainTruss
Construct galvanised steel stage curtain truss consisting of hollow sections, channels,
galvanised steel plates, etc. welded together including painting with two coats of
primer before delivery to site.
2.08 Aluminium Work Generally
a) All aluminium works stated hereof shall be fluorocarbon finish to Engineer's
approval unless otherwise stated.
b) All aluminium members shall be factory fabricated to the best standard of
workmanship and under experienced factory supervision and control. Shop
drawings shall be submitted to the Engineer for approval prior to
prefabrications.
c) All joints in frames at corners, junctions or intersections, shall be electrically
welded, or mechanically cleated or made with the best trade type of joints
with all due care.
d) All aluminium sections shall be so designed to suit the required height and
span and comply with statutory requirements on lateral loadings where
applicable.
e) Samples of flurocarbon coated aluminium sections shall be submitted to the
S.O. for approval prior to commencement of work.
2.09 Aluminium Windows, Louvred Windows, Doors, Etc.
a) Supply and fix approved aluminium top hung, sliding windows, etc complete
with frames, mullions, transoms, ironmongery, weather strippings, glazing
beads and other matching accessories.
MTECH CONSULTANTS
S2/15
b) Supply and fix approved aluminium adjustable louvred window frame and
fittings with poly-propylene clips to receive 6mm thick x 150mm wide glass
louvres and 150mm wide aluminium blades, screwed to aluminium frames
including control mechanism, flush handle and coupling mullion etc.
Separate control mechanism for aluminium blades and glass louvres.
c) Supply and fix approved aluminium fixed louvres in accordance with
manufacturer's details.
e) Supply and fix aluminium louvred door.
f) Supply and fix aluminium flush doors infilled with foamed polyurethane.
g) All windows, sashes and other opening units shall have weather stripping of
rubber gaskets, neoprene setting blocks and approved silicon water-resistant
sealer, and doors shall have weather stripping of certified high pile wool
mohair with silicon water-resistant treatment to eliminate water leakage in
extreme weather conditions. All joints between aluminium head or cill and
concrete surfaces shall be also similarly treated with silicon water-resistant
sealer.
h) All units shall be prepared for glazing with aluminium glazing beads, non-
setting putty and/or press-fit rubber gasket or other equal and approved
proprietary method.
i) All aluminium sections for double leaf doors shall be of single piece rebated
sections.
2.10 Aluminium Catladder
Supply and fix natural anodised aluminium cat ladders.
2.11 Roller Shutters
Supply and fix manually operated roller shutters constructed of zinc and aluminium
coated and colorbond steel curtain material permanently lock-seamed to form a
continuous curtain with the edges treated with self-lubricating seamless braided
nylon polyglide to prevent metal to metal contact. The drum assembly shall consist of
suitably graded oil-tempered torsion springs secured to drumwheels moulded from
engineering plastics. The curtain top shall be fully secured and wrapped around the
drum assembly to form a cylindrical tongue tube which is to be bored up. The bottom
rail shall be an extruded aluminium section lock-seamed onto the bottom of the
curtain with the base of the rail containing two slots to retain seamless finned pvc
weatherhood. Locks shall be dual mode waist-high lock with finger-grip recesses. All
in accordance with the manufacturer's details.
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2.11 Roller Shutter (Cont’d)
Safety Stop : When the resistance is felt while closing the roller shutter, then the
motor stops.
Quality : Prime quality.
2.12 CANCELLED
MTECH CONSULTANTS
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SECTION 3 DRAINAGE WORKS
1.0 General
The whole of the works shall be executed in accordance with the current
‘Standard Specification for Drainage Works’, Code of Practice for Surface Water
Drainage, Drainage Regulations of the Drainage Department of the Environment
Ministry (ENV), Drainage System Regulations and latest Code of Practice on Sanitary
Plumbing and Drainage System of the Environment Ministry, Singapore.
1.1 Materials
The materials shall generally follow that stated under “Notes” in the drawings. The
concrete and steel reinforcement generally shall be as described in Section 10 -
Reinforced Concrete. The brick masonry shall be as laid out in Section 13 - Masonry.
Vitrified clay pipes and fittings shall follow the requirements of BS 65 and BS 540 and
shall be provided with approved flexible joints to BS 2494.
Corrugated steel multi-plate pipe shall be in accordance with AS 2041 and AS 2042.
Precast concrete culverts ( open or boxed ) and slabs shall be tested to SS 183, 214, BS
7263 and to the requirements of Section 10 - Reinforced Concrete.
Rubber ring or polyester type fittings shall also comply with the provisions of SS 270.
The formed polyester shall be securely bonded to the vitrified clay. Pipes having loose
or damaged rings of socket packings shall not be used.
Unless otherwise specified, such as limestone aggregate or PVC lining, use approved
flexible jointed thickwall concrete pipes and vitrified clay pipes with flexible joints in
accordance with current specifications, SS 183 where applicable, and testing
requirements of the Drainage Department of the Environment Ministry (ENV).
1.2 Pipes
1.2.1 Reinforced Concrete Pipes
Concrete pipes, bends, channels for drains, manholes and culverts shall be obtained
from an approved manufacturer and shall be made from Portland Cement and the pipes
( preferably spun reinforced concrete pipes ).
If permitted by the Engineer, the pipe may have collar joints when socketted pipes are
unavailable. Socketted pipes shall have the sockets cast with the barrel of the pipe.
All drains using reinforced concrete pipes and are of nominal internal diameter between
300mm and 825mm shall comply with the requirements of Sewerage Department ,
ENV.
The joints shall be of a type that remain completely watertight while accommodating a
rotation of 5° in any direction taken from the axes of either connecting pipe at the joint.
1.2.2 Pitch - Fibre Pipes
Pitch fibre pipes and fittings shall be of an approved type and manufacture conforming
in all aspects with BS 2760. They shall comply with the requirements of the Drainage
MTECH CONSULTANTS
S3/2
Department, ENV. The joints shall be of a design to permit flexibility and movement
without leakage.
1.2.3 Cast - Iron Pipes
Cast-iron pipes and specials and cast iron ( spun ) pipes shall comply with the
requirements of BS 4622 ,BS 1211, BS 2035 wherever applicable and shall be Class 1.
The term cast-iron also embraces spun-iron where applicable.
Unless otherwise indicated, joints to cast iron pipes shall be ‘screwed gland’, ‘bolted
gland’ or a proprietary rubber ring joint ‘Tyton’ or other approved.
Gaskets for flanged pipes shall comply with BS 2494 and BS 3063 and shall be full
face, Class ‘D’ of nominal thickness 3mm. Bolts, nuts and washers shall be in
accordance with BS 4190 and BS 4320. Where flanged bolts are to be installed and
buried underground, the bolts, nuts and washers shall be non-ferrous or metal coated to
prevent corrosion.
1.2.4 UPVC pipes
Unplasticised polyvinyl chloride ( UPVC ) pipes and fittings shall be of an approved
type and manufacture complying with the requirements of the Drainage Department,
ENV. They shall conform to SS 272, BS 4660, BS 5481 and the relevant Australian
Standards where applicable.
1.2.5 Corrugated Steel Multi - Plate Pipe
Yield Stress : 230 MPa
Elongation : 16 % on a gauge length of 200mm
The tests shall be carried out in accordance with AS 1391
Unless another type of coating is specified, sheets which are HDG after fabrication
shall have an average coating of not less than 600 g/m2
( total both sides ) as
determined by the spot test method described in AS 1650.
The pitch of the corrugations in the sheets shall be 13 ± 1.5 mm. The corrugations shall
form smooth continuous curves and tangents. The inside radius of each corrugation
shall not be less than one-half of the depth of the corrugation.
1.3 Earth Drains
1.3.1 Table drains
Table drains shall be provided at the outer edges of the berms in cuttings as shown on
the drawings and other locations as directed by the Engineer. Table drains shall be
evenly graded throughout their length without stepping and shall be flared outwards
from the formation. Table drains shall be diverted at the intervals as shown on the
drawings so as to discharge water into the open drains, water courses, culverts or upon
natural ground such that a natural gravity induced flow pattern results in proper
drainage flow in the required direction.
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1.3.2 Catch drains and other open drains
Where the natural surface drains towards cuttings, catch drains shall be provided,
before or during the excavation of the adjacent roadway, above each cutting as shown
on the drawings or directed by the Engineer. The edge of the catch drains shall not be
less than 2.5 m cuttings nor more than is necessary to maintain the fall of the drains.
Catch basins shall generally by at least 300mm deep and side slopes not steeper than
the batter applicable to the material through which they are cut. The gradient shall be
designed to ensure free flow of water and shall not be less than 1: 100 unless otherwise
directed by the Engineer.
Catch drains shall be cut in uniform lines. Where obstructions occur in the line of a
catch drain, the drain shall be diverted in a manner satisfactory with the required
performance and as directed by the Engineer. Where hard rock occurs along the line of
the proposed catch drain, the Engineer may propose the use of graded banks to
intercept the water or that the catch drain be dispensed with and that the provision be
made for interception of the drainage further away from the cutting or for widening or
deepening the table drain into which the water will flow.
Where graded banks are required in-lieu of catch drains, the Contractor shall construct
in the same location an embankment not less than 450mm high by 300mm wide at the
top, with both side slopes not steeper than 2 horizontally to 1 vertically ( 2: 1 ).
Material for the embankment shall be obtained either from the excavation work or by
neatly or uniformly trimming back the top edge of the batter of the adjacent cutting.
At side roads and vehicle entrances, catch drains shall be diverted to the table drains or
other drainage system available as directed by the Engineer. Where shown on the
drawings or as directed by the Engineer, longitudinal median drains shall be provided
between divided carriageways. Other open drains shall be provided at outlets from
catch drains, table drains, subsoil drains, kerb and gutter and all other points of water
concentration to lead the water in approved paths to underground drainage systems. As
far as practicable, the water shall seek its own level by following existing watercourses
and depressions in the natural ground or by following underground flow patterns
through pervious layers in the soil and rock.
1.3.3 Lining of earth drains
Where shown on the drawings or as directed by the Engineer, earth drains which have
a gradient of at least 5% shall be stone-pitched or concrete lined. Pitching shall consist
of sound durable rock not less than 150mm thickness or precast concrete blocks not
less than 100mm thickness, properly bedded on approved loam or sand to present a
uniform surface. The exposed surface of each stone or block shall be flat and not less
than 0.03 m2
. Joints between adjacent stones or blocks shall not be larger than 12mm.
1.4 Precast concrete drains and box culverts
The precast concrete sections shall be true to shape as given in the Drainage
Department’s size catalogue. All units delivered to site shall be inspected and free from
defects before being allowed to be used in any part of the works. Precast channels,
revetment slabs, etc. shall be properly laid to fall, bedded on a sand base at least 75mm
thick unless otherwise stated and joints poured with cement mortar. Precast box
culverts and drains requiring built-up sections as additional wall and roof slab sections
shall be made to the provisions of the drawings and Section 10 - Reinforced Concrete.
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1.5 Subsoil Drains
1.5.1 General
Trenched for subsoil drains for pipes up to 150 mm in diameter shall be excavated to a
width of at least four times the nominal diameter of the pipe or as shown on the
drawings. For a pipe diameter above 150mm, the width shall be the external diameter
of the pipe plus 450 mm or as shown on the drawings. Unless otherwise stated, drains
shall consist of 19mm aggregate with a perforated 100mm PVC pipe at the bottom. The
whole of the drain shall be wrapped in a layer of geofabric complying with Class B as
shown in Table 21.1 in page S21/4. The subsoil shall be bedded on a 50mm thick lean
concrete base with a maximum aggregate size of 10mm.
1.5.2 Geotextiles
Table 21.1 Physical Properties of Geotextiles
Class of Geotextile
Physical property
Class A Class B
Specification
Minimum Unit Weight,
g/m2
125
50
ASTM D3776
Minimum Grad Tensile
Strength, N
530
270
ASTM D1682
Minimum Elongation to
Break, %
60
55
ASTM D1682
Minimum Trapezoidal
Tear Strength, N
180
80
ASTM D1117
Minimum Mullen Burst
Strength, N/mm2
1.10
0.50
ASTM D774
Water Permeability,
cm/sec
2.0 x 10-2
2.7 x 10-2
Manufacturer's test
report to be
submitted
Generally non-woven type geotextile may be used and shall be from the following
materials :
( a ) polypropylene
( b ) polyethylene
( c ) ployamide
Ensure that all geotextiles are protected against direct sunlight and contamination of
chemical solutions while in storage. Only minimum exposure to weather during laying
is permitted. Geotextiles with stain markings shall be rejected. The following tests shall
be carried out when required by the Engineer :
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( a ) Load vs Strain to ASTM D 1682
( b ) Grab Tensile Test to ASTM D 1682
( c ) Trapezoidal Tear Test to ASTM D2263-68
( d ) Mullen Burst Test to ASTM D751 -73
( e ) Water Permeability Test
( f ) Pore - Size Distribution Curve
1.6 Scupper drains
These shall be laid from the roadside drains to the concrete kerbs. Revetments and
channels to the roadside drain shall be broken into to place and connect the scuppers
and the connections made good with cement mortar mix. Each pipe shall be properly
bedded down and all but joints sealed all around with cement mortar filleted up to form
a collar 50mm wide by 25mm thick.
1.7 Excavation
1.7.1 General
Excavation shall be carried out to the requirements of Section 3 - Excavation and to the
relevant requirements of the Drainage Department, ENV. The Contractor shall provide
the necessary scope of excavation works to the Engineer prior to commencement for
approval. The Contractor shall also obtain all permits and carry out trial trenches and
location of services as required.
1.7.2 Excavation proper
The Contractor shall notify the Engineer sufficiently in advance of the beginning of
any excavation. The natural ground adjacent to the structure shall not be disturbed
without permission of the Engineer.
The excavation of the trenches shall be to lines and gradients required for the pipes,
channels, etc. The trench bottom shall be of sufficient width to allow adequate working
space for the pipe joiners. Unless otherwise specified, excavated material shall not be
deposited within 500mm of the edges of the trench.
The sides of the excavation shall be supported by planking and strutting if necessary
to ensure the proper execution of the work. Trenches shall be provided with planking
and strutting for depth of excavation not less than 1.5m.
The method and materials for planking and strutting are to be certified by the
Contractor’s P.E. and approved by the Engineer. In the event of excavation being
made deeper than necessary, they shall be made up in Grade 15 concrete at the
Contractor’s expense. The excavation shall be kept free from water by pumping,
baling or otherwise.
Brace all excavation adequately and securely with suitable timber using the methods
indicated in the drawings and otherwise certified by the Contractor’s P.E. and approved
by the Engineer. Notwithstanding the approval given, the Contractor is to improve ,
alter , strengthen and inspect the shoring from time to time.
The Contractor shall be responsible for any damage to the works therefrom. Any
permission by the Engineer to carry out a certain form of works based on the
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Contractor’s methodology does not relieve the Contractor from carrying out the said
works to a safe and required standard of construction as required by that methodology.
The foundation pits for structures shall be excavated to the lines and levels
shown on the plans or as indicated by the Engineer. They shall be of sufficient
size to permit the placing of structures at the full width and length shown. Boulders,
logs and any other objectionable material encountered in excavation shall be removed.
After the excavation is completed, the Contractor shall notify the Engineer to that
effect. No bedding or pipe shall be placed until the Engineer has approved the
excavation and the character of the foundation materials.
In the particular case of materials left in the excavation, this shall be approved by the
Engineer and such materials shall be removed to the best of the ability of the contractor
before closure of the excavation
The Contractor shall take any action required by the Engineer when, in the opinion of
the Engineer, the excavation or related works are deemed to be of a standard which
would cause concern for the safety of personnel or for the execution to achieve a
required standard of the works.
1.7.3 Bakau piling
Provide piling to the drawings and the requirements of Section 20 - Timber Piling and
especially to Clause 20.13 and related sections where required.
1.7.4 Pipe-laying works
(a) General
Except for sub-clauses below, the pipe shall be placed on a firm earth foundation of
uniform bearing capacity for the entire length of the structure and to the line, levels and
camber established by the Engineer. Where rock or other unyielding materials is
encountered it shall be removed to at least 300mm below the bottom of the structure.
The width of the excavation shall have a minimum of 600mm greater than the pipe
diameter. The excavated area shall be backfilled with selected material and be
thoroughly compacted to provide a cushion for the structure.
When soft, spongy or other unstable soil is encountered at the level established, it shall
be totally removed and replaced with well compacted granular material to provide a
uniform and adequate support for the pipe. Under these conditions the width of the
trench shall be at least three times the pipe diameter and as deep as the foundation
condition requires and as directed by the Engineer. Unless otherwise specified, the
foundation shall have a thickness of 300mm.
(b) Pipe laying
Carefully brush all pipes inside and visually test for soundness before laying the pipes
on the compacted foundation material or concrete. Lay the pipes to true inverts, straight
lines and falls, each pipe being separately bonded between sight rails and bearing
evenly on the supports for the full length of the pipe.
Where pipes are to be laid on rock cutting, take the excavation down 100mm below the
bed level and ensure that no projecting pieces of rock are present which may ride the
pipe. Make up the bed to its true line and level by refilling with either 100mm of
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consolidated, selected material from the excavation, well rammed and watered as
necessary or with 100mm of compacted sand or with G15 benching concrete as
required.
Where pipes are to be supported on a bed of concrete surrounded with concrete,
provide rectangular blocks composed of concrete made in approved moulds at least 14
days before use and approved hardwood folding wedges. Provide two blocks for each
pipe set and bond into the correct level on the formation bottom and lay the pipe on
them properly centred and socketted.
1.7.4 Pipe-laying works
(b) Pipe laying
Two hardwood folding wedges of a width equal to that of the concrete block shall then
be inserted between the body of the pipe and the block and shall be driven together
until the pipe is brought to the exact level required. Blocks and levels shall be left
undisturbed while the pipes are being joined and the concrete surround is being placed
in position. Ensure that the procedure does not cause settlement or compensate for the
settlement so caused. For lengths of pipe, deflected on plan, the curve shall be obtained
by the deflection of each pipe at each joint position.
1.7.5 Jointing
(a ) Cast - iron pipe
In general for all types of joint, thoroughly clean the pipe joint and the jointing ring or
material of dirt and grease before any jointing commences. The pipes shall be properly
supported, bedded and lined-up before the joint is set and made. Refer to Section 21.3.4
for laying operations. Make bolted glands, screwed glands, and similar types of flexible
patented joints in accordance with the manufacturers’ instructions. Clean the joint
rings, lubricate with the manufacturer’s recommended material and accurately position
it. Firmly push or jack home the joint and where screwed or bolted glands are involved
steadily and evenly tighten the glands all around.
No lead caulked joints shall be permitted. Carefully clean the flanged joints, center and
line up with only 3mm allowed for the gasket between the faces of the flange. The
flanged gasket shall be carefully positioned and held by the flanged bolts.
(b) Vitrified clay pipes
In the case of vitrified clay pipes with flexible joints, similarly brush clean the spigot
and the socket of each pipe before the rubber ring is placed in the groove. Apply an
approved soft soap lubricant to the rubber ring and the inside face of the socket. Insert
the spigot into the socket and push straight home.
Where vitrified clay flexible joints are used, the manufacturers’ specifications shall be
deemed to form part of this Specification. Ensure that no damage to the joints are
caused during handling, stacking and laying. Such damaged goods are deemed
unacceptable for use and shall be removed from the site immediately.
(c) Concrete pipes
Push well home the concrete pipe with the rubber ring aligned on the spigot into the
socket of the previously laid pipe by means of uniform pressure with the aid of a jack
MTECH CONSULTANTS
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or similar appliance. Use a roll on rubber ring and well lubricated before making the
joint by the use of soft soap, water or other approved lubricant supplied by the
manufacturer. The manufacturer’s instructions on the system shall be deemed to form
part of this Specification.
Lay the PVC lined concrete pipes and join as specified above except that all necessary
precautions shall be taken to protect and safeguard the PVC lining from any damage
during pipe laying. After the pipes have been approved as laid by the Engineer,
‘Thermo weld’ the cover flaps of the PVC across the pipe joints according to the
manufacturer’s instruction and this shall be carried out in conjunction with the pipe
laying progress.
1.7.5 Jointing
(c) Concrete pipes
Where the lined pipes enter the manholes and other structures, seal the PVC lining by
welding of approved preformed cover fillets or angles forming returns to the arises built
into the in-situ concrete work.
The manufacturer’s drawings and instructions for jointing and the ‘Thermo Weld’
procedure are to form part of the Specifications. The manufacturer shall submit to the
Engineer the methods for field testing of the PVC lining and ‘Thermo weld’ joints for
flaws, burnt surfaces, pin holes etc. Employ approved methods for the complete testing
of the lining, jointing, and welding throughout the line.
(d) Corrugated steel pipe
Damage to the items delivered to the site by improper handling, stacking and placement
is required. Dragging pipes over rock or gravel may damage the external coatings and
is to be avoided. All spots damaged shall be repaired with two coats of hot bituminous
coating or otherwise and repaired in a manner approved by the Engineer. The
corrugated sections shall be assembled progressively in accordance with the
manufacturer’s instructions. Base plates shall be checked for line and levels after
assembly and after laying the pipe. All bolts and nuts shall be tightened either by air
compression or engine /electrical driven machine having a controlled torque of up to
0.405 kNm.
A hand torque wrench shall be used for random testing on the tightness of the bolts.
Bolts shall not be overtightened. Standard bolts shall be furnished in two lengths - short
where the plates lap and long for drawing the plates are drawn together and then
replaced by the short variety.
1.7.6 Fracture of pipes
In the event of the pipes being fractured after being, to all appearances, properly laid,
whether due to imperfect beds having been formed or the materials for refilling having
been improperly selected or due to any other cause, the Contractor shall be responsible
and shall be called upon to replace such defective pipes if such pipes have been
identified before the end of the Defects Liability Period. Immediately remove any
length of pipe so affected and remake all leaking joints.
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1.7.7 Clearing pipes of obstruction
After testing the pipelines as specified and at a time to be directed by the Engineer,
inspect the interior of the pipelines to ascertain that the liens are entirely clear of
obstruction and that the invert is smooth. The outside diameter of the ends of the
plugshell not be smaller than the diameter of the pipe through which it is to be passed
by and its length shall not be less than its diameter.
The Engineer may not instruct the Contractor to carry out this test until he is satisfied
that the lengths concerned are complete and ready for operation. After testing, remove
all obstructions and remake any unevenness to the invert to the required standards. If,
as a result of such removal, the Engineer considers any damage may have been caused
to the pipelines, the Contractor shall be required to re-test and make good those lengths
affected. Should such testing show any deficiency in the works, remedy the defects as
required on the instruction of the Engineer.
1.8 Testing gravity pipelines
Test all gravity pipelines and drains of 525mm or less in diameter before being
surrounded and covered by filling with water in a manner approved by the Engineer.
The pressure shall be measured from the highest point of the pipeline under test and
shall be a 1.2m head of water. Pipelines shall not be accepted until they have withstood
the required pressure for 30 minutes without loss in excess of 1.5 litres for a length of
100mm for each 300mm diameter of pipe.
Where the maximum head at the lower end exceeds 2.5m, the sewer shall be tested in
sections at the discretion of the Engineer and the Contractor shall make all necessary
arrangements for the testing. Gravity sewers larger than 525mm diameter shall not be
hydraulically tested but the joints shall be inspected and shall be made good to the
satisfaction of the Engineer.
The pipes shall not be covered until they have been tested and/or inspected , and
passed.
After each section of pipe has been tested and passed, bed haunch and surround the
pipes with G30 concrete as required in the drawings. At approximately every 6m or
four pipes , whichever is lesser, form a joint in the concrete bed or surround by
vertically shuttering the bed or surround with a 25mm thick fibreboard, timber or other
approved material. Leave the shuttering material in to form a permanent joint. Where
the concrete bed is required to be reinforced, stop all reinforcement on either side of the
joint. The whole of the joint shall be thoroughly set before any refilling works
commence.
1.9 Tumbling bays and backdrops
Use special spigot and socket junctions in the junction between two lines of pipes. For
backdrops and tumbling bays more than 300mm in diameter, the junction shall be cast
iron to approved dimensions and shape. Lay the tumbling bays or backdrop pipes on a
concrete foundation and completely encase in 150mm G30 concrete surround as shown
in the drawings.
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1.10 Inspection Chambers
1.10.1 Masonry I.C.
Construct all masonry i.c. to the requirements of Section - Masonry. Render the base of
the chamber with cement render 20mm thick. Flush point internal and external joints of
brick chambers in 1:3 cement mortar and finish to a smooth surface.
1.10.2 Precast I.C.
Set the individual pieces of the chamber walls on a preformed r.c. foundation
comprising a G30 base and a built up cast-in-situ r.c. section ( if required ) and as
shown on the drawings. Construct the base, benching and pointing of all precast and in-
situ concrete chambers in OPC unless otherwise directed. Form the benching at the
soffit level of the outgoing sewer pipe rising by 75mm to the manhole walls. Form
curves and junction benchings to a radius in the centre line of the channel not less than
one-and -a- half times the diameter of this pipe.
Set the r.c. slabs covering the chambers and shafts of the i.c. in 1:3 cement mortar to
form a watertight joint. Form channels and benching to the concrete floors of the
concrete i.c. in OPC concrete and to the required levels and falls. Set i.c. covers and
frames as specified herein in cement mortar and surround with G30 concrete and covers
to be left flush with the level of the finished road surface, ground or otherwise agreed
datum with the Engineer.
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1.11 Backfilling of drain trenches and excavation
Earthfilling from the bottom of trenches and to a height of 300mm
above the top of the pipes shall be of selected materials, compacted, watered if
necessary and well rammed on either side of the pipes.
The remainder of the earthfilling shall be in layers of 300mm each, watered if
necessary and well rammed with mechanical rammers or other efficient means of
effecting compaction.
The pipes shall be carefully handled during this operation. In the opinion of the
Engineer, if such work causes damage to the pipes then the Contractor shall rectify the
damage to the satisfaction of the Engineer before proceeding with the remainder of the
works.
1.12 Pipe jacking
1.12.1 General
Where specified, sections of the sewer shall be laid by pipe jacking. Alternatively, the
Contractor may propose the pipe jacking method provided that the overall scope of
works are not, in the opinion of the Engineer, affected by such a method.
Submit details of the construction equipment, materials and the method of laying and
construction to perform and complete the work for approval by the Engineer before
commencing these operations.
Approval by the Engineer shall not relieve the Contractor of the sole responsibility in
ensuring the safety, efficiency, reliability or completeness of the method employed to
carry out this particular form of construction.
The general soil profile along the route of the sewer at depth shall be given in the
borelogs for the information of the contractor only. The interpretation, design,
execution and delivery of the final product shall rest solely on the Contractor. The
Employer accepts no responsibility for the accuracy, reliability or completeness of this
information. The Contractor is to ensure the soil conditions along the route at his own
expense.
Maintain stable soil conditions at the jacking face to prevent loss of ground above the
jacking operation and the subsequent movement of the surrounding soil. The methods
of maintaining face stability and preventing ground movement and subsidence shall be
by means of compressed air or other plenum methods where fluid slurry or earth
pressure is applied to the tunnel face.
Alternatively, stabilise unstable ground ahead of the jacking face by the injection of
suitable chemicals methods which require dewatering of the soil and methods which
may lead to significant loss of subsurface material shall not be accepted. Soil
stabilisation methods shall be submitted to the Engineer for approval.
Movement and other settlement monitoring shall be provided of structures, utilities and
pavement by the Contractor to the Engineer and which are continuously assessing the
ground conditions between the surface and the jacking levels during the course of the
works.
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If movement or settlement occurs which, in the opinion of the Engineer, may cause
damage to existing structures or the works, then immediate action shall be tank to
prevent further movement and rectify the damage taken place to the satisfaction of the
Engineer.
1.12.2 Materials
The pipes for the jacking operation shall be precast reinforced concrete pipes. The
pipes shall be manufactured by a centrifugal or other equivalent process to be approved
by the Engineer. Design, manufacture and factory testing of the pipes and specials
shall be to SS183, BS 5911 or AS 1342 or other acceptable standards. All pipes shall be
manufactured with two sets of grout holes. Each set shall consist of three grout holes
spaced at 120° on centres circumferentially located at quarter points from either end of
the pipe section.
The precast reinforced concrete pipes shall be sufficiently reinforced with steel
reinforcement to withstand all stresses induced by handling, jacking , earth and water
pressures at the depths they are to be placed during service without cracking, spalling
or distortion to the limits of the relevant codes for water retaining structures especially
the required limits in BS 8007.
The pipes shall be at least of Class ‘H’ designation. A load factor of not larger than 1.5
shall be used in the calculations to determine the strength of the pipes required. The
strength of the pipes shall be tested by the ‘three edge bearing’ test. When subjected to
the design load in such a test, the maximum crack width developed on the pipe shall not
exceed 0.25 mm.
The full details of the proposal including detailed drawings showing pipe sizes,
reinforcement details, types of joint, calculations on pressure on pipes etc. together
with the name of the nominated manufacturer, place of manufacture, process used and
any other pertinent data shall be submitted to the Engineer for approval.
The joints supplied shall be of the Cornelius rubber ring type or similar approved. Joint
rings shall comply with BS 2494 Part 2 for Grades between B and D.
All workmanship and materials shall be subject to the approval of the Engineer who
will from time to time inspect the materials at the source and the plant of manufacture
during the manufacturing process.
The pipes shall be sufficiently mature before they are used in the works. Repaired pipes
shall not be used in the Contract. The Engineer shall reject any material including pipes
if they do not meet the criteria submitted by the Contractor or, in the Engineer’s
opinion, the relevant sections of the codes.
Every pipe shall be marked after inspection and catalogued according to the date of
manufacture, date approved for works, number of the pipe to leave the factory and the
testing authority. test certificates from the manufacturers or other relevant authority
shall be submitted to the Engineer.
Where steel collars are used for pipe joints, they shall be made from Grade 43 steel to
BS 4360. The collars shall be of the dimension and thickness to be approved by the
Engineer. Before being fitted to the pipes, the collars shall be coated with an approved
anti-abrasive and anti-corrosive material such as polymorphic resin or equivalent.
MTECH CONSULTANTS
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Where a steel shield is used for jacking operations, bolt by approved methods the first
pipe to the shield. A jacking ring can be of either r.c. or structural steel and shall be
used at all times when a pipe is being jacked. The jacking ring shall allow the even
distribution of the jacking pressure around the wall of the pipe.
The jacking frame shall be used during all operations and designed to distribute the
stresses evenly from the jacks to the jacking ring in an even manner.
1.12.3 Jacking operations
The Contractor shall be fully responsible for the materials , construction equipment and
facilities required in conjunction jacking the reinforced concrete pipes.
Before starting work, submit to the Engineer for approval a detailed schedule of the
entire jacking operation. Approval of such schedules shall not relieve the Contractor of
his responsibility to provide a fully satisfactory installation. Provide together with the
submission evidence of successfully completing other projects in a similar manner to
that proposed. Where the Contractor proposes to use compressed air, his proposal shall
include the relevant sections in the ‘Specifications for Working in Compressed Air’ and
‘Work in Compressed Air’.
Where chemical stabilisation of the soil is required, pressure injection of a chemical
grout into the soil over and in front of the jack shall be used to stabilise the soil. The
chemical grout used shall have a demonstrated history of success for stabilising soils
similar through that which the pipe is being jacked. Where a mechanical shield is being
used, provide past cases of jacking capability in soils of the type currently encountered.
Jack the pipes in place true to line and level. The maximum tolerance allowable in the
displacement of the centreline of the laid pipe from the designed centreline is 50mm in
the horizontal plane and 25mm in the vertical plane but there should be no backfall at
any point. Any pipe not meeting the requirements for tolerance shall be removed or
repositioned to achieve the tolerances.
There shall be provision to prevent the relative movement between pipes at joints by
use of steel gaiters or other approved methods during the jacking operations.
Furnish, install and remove thrust blocks or provisions involved in driving the pipes
forward. Provide means to initially align the pipes in the pits by use of beams or rails
and submit proposals for approval to the Engineer. Monitor closely the progress of the
jacking operation. Daily site logs of thrusting pressures and line and level
measurements shall be maintained and submitted immediately after the day’s work or
in 24 hour cycles for continuous work.
Carry out any remedial works to ensure a watertight structure during the works and the
period of Defects Liability to the requirements of the Contract.
1.12.4 Cement grouting
Prevent the occurrence of voids outside the pipe and if they occur, fill immediately with
cement grout. Immediately following the jacking operation, pressure grout the jacked
section to fill all the voids outside of the pipe. Grouting shall be from the inside
through the grouting holes as provided.
Provide a system of standard pipe, fittings, hose and special grouting outlets embedded
in the pipe walls. All parts of the system are to be free from dirt. Carefully force grout
MTECH CONSULTANTS
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composed of cement, sand and other approved compounds under a steady pressure into
the grouting connections at the invert and proceed until the grout flows in from the
upper connections. make connections to these holes and repeat the process until
completion.
After grouting, maintain pressure by means of stop cocks or other means until the grout
has set sufficiently. After grout has set, completely fill the grout holes with concrete
and finish neatly. For pipes with PVC or HDPE linings carry out grouting and ensure
that lines are watertight before proceeding with the jointing of the linings of the pipes
and the patching of the linings over the grout filled holes.
1.13 Inspection Chamber
1.13.1 General
All inspection chambers shall be made monolithic with the pipe sections placed by
trenching or pipe jacking. The inspection chambers shall be constructed to the drawings
and the relevant sections of the Specifications, particularly Sections 3, 10, 13 and this
Section.
The chambers shall sit such that the grades of the main pipes entering and leaving shall
not be affected by the depth to invert at any point of the chamber. The benching on the
concrete base shall be not less than that specified. The pipes shall be inserted a
minimum of 75mm into the walls of the chamber and made watertight with approved
cement grout mixture or a thixotropic sulphate-resisting non-shrink binder to the
approval of the Engineer.
The chamber proper shall be made watertight in the manner described for water
retaining structures under Section 10 - Reinforced Concrete and shall have adequate
access equipment for inspection of the base as and when required.
1.13.2 Inspection Components
Handrailing for access shall be provided as shown on the drawings. All mild steel pipes
used for handrails shall be light steel tubes of 40mm nominal bore to BS 1387 and SS
17. All mild steel tubes shall comply with BS 15 or SS 104.
Before erection, wire brush to remove all rust and mill scale. Paint the handrailing with
one coat of red lead oxide primer or equivalent approved. After erection, paint the
handrails with one undercoat of approved oil based paint and one similar finishing coat.
Safety Chains shall comply to the drawings and the requirements of Drainage
Department, ENV. They shall be made of aluminum alloy HE 30 FT.
Ladders shall be made of aluminum alloy HE 30 FT and of approved design to BS 1474
and BS 2037. Each rung shall be either cast-in to the concrete walls or bolted with two
bolts per connection end.
All HDG gratings shall be zinc coated and in accordance with SS 117 or BS 729 Part 1.
The amount of zinc coating shall comply with the following average coating mass:
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Thickness of Steel in G43 Average Coating Minimum Permissible
grammes/m2
grammes/m2
5mm thick and over 610 580
Under 5mm but not less than 2mm 410 390
Under 2mm 350 330
Inspection covers and frames shall comply with SS 30 and BS 479 and be of the
standard size nominated by ENV or LTA. Test loads shall be obtained from the
relevant authorities.
Step irons shall be of malleable cast iron and comply with BS 1247 and used only
under the direction of the Engineer.
S4/1 MTECH CONSULTANTS
SECTION 4 -EXTERNAL WORKS
Note:
All specification items contained in other sections of this Specification shall apply equally to
External Works.
1. Site Clearance
The Contractor shall take over the site from the Piling and Earthworks Contractor and shall
ensure that weeds, shrubs, undesirable growths and debris are removed off the site at the
beginning and for the duration of the construction operations.
2. Earthworks
Excavation and filling to buildings or over site to make up or reduce levels in forming
embankments, terraces, roads paving, turfed areas, etc. shall be carried out and graded to levels
and falls as shown on the site plan or as directed on site.
Filling to be with selected excavated material free from roots and all vegetable matter, filled in
and well consolidated in layers not exceeding 150mm thick.
Carefully form all banks in cutting or filling to constant or varying angles as directed.
All surplus excavated materials deposited in spoil heaps on site shall be removed to a designated
area adjacent to the site or disposed of as directed.
3. Turfing and Tree Planting
General
The Contractor shall allow in his overall tender price to cover small quantities and spot items of
turfing works to be done at various spots on site as required by the Engineer.
Materials
The grass to be used in turfing shall be good quality approved cow grass (Axonopus Compressus)
and shall be of healthy and vigorous stock.
Turfs shall be cut square, not less than 35mm thick and of size 300 x 300mm with square edges.
The root formation shall be moist, undamaged and solidly embedded in planting mixture.
The grass shall be green, not more than 35mm long and free from weeds, Care shall be taken to
include as much of the root growth as possible.
Turfs shall be laid within 36 hours after being cut. It shall be stacked on site roots to roots and
grass to grass and shall be kept moist by being sprayed with water and covered with wet sacking.
Turfs shall be inspected immediately before laying and all turfs which contain weeds shall have
the weeds grubbed out complete with roots and destroyed. All turfs which are dry, have long
grass, or otherwise not conform with this Specification shall be removed from site.
S4/2 MTECH CONSULTANTS
3. Turfing and Tree Planting (Cont'd)
Materials (Cont'd)
The Contractor shall produce sample turfs for the Engineer's approval before commencing work
and all turfs laid shall conform to the approved sample.
Tree shall be of selected stock and shall be obtained from an approved source and shall be
minimum 12 months old, healthy and delivered to site in their original planting boxes.
Turfing
The Contractor shall supply approved quality top soil and sludge, site thoroughly and spread and
level to a 50mm thickness to all areas to be turfed. Prior to turfing, spread throw evenly approved
rock phosphate fertilizer at the rate of 0.3kg per square metre to top soil and raked in.
Turfs shall be laid with joints closely butted together. After laying, each turf shall be
consolidated until it is well bedded without excessive beating. Any hollow so produced shall be
packed up from underneath with planting mixture and the turf again beaten. Laying and beating
shall continue until a solidly bedded continuous turf area is produced, true to the levels and
gradients shown on the Drawings. On slopes exceeding 1 in 4 the turfs shall be pegged down
with two or more split bamboo pegs to each turf.
A patchwork effect to the finished turfing shall be avoided. Turf which contains an undue
preponderance of a coarse or fine species of grass may be used at the Engineer's discretion if
distributed evenly among the general turfing, so as to avoid a sudden change in turf's texture.
The minimum total thickness of turfs and planting mixture shall be 135mm. This shall be
measured after the turf has been laid and beaten down. Small trial holes shall be dug for this
purpose in positions indicated by the Engineer. Turfing which shows less than the 135mm
specified shall be taken up, the correct depth of soil provided and turf re-laid at no extra cost to
the Contract.
As soon as the turves have started to grow, approved type of sulphate of ammonia shall be spread
at the rate of 34 gms per 3 square metre to all turfed areas, followed immediately by generous
spray of water.
Grass cutting shall only be carried out after about two months after planting and thereafter once
every month.
When mowing on spot-turfed areas, care shall be exercised to see that the growing roots or shoots
are not cut or damaged. All cut off grasses shall be distributed and left on the turfed areas. Cut
off grasses arising from subsequent month mowing shall be lightly plastic raked together and
removed from site.
Following each grass cutting, the turfed areas shall be rolled over with a smooth roller not
exceeding 181 kg (400 lbs) in weight.
The Contractor shall be required to maintain the turfs continuously until the end of the
Maintenance Period including watering, tending and weeding until the turfs are growing
satisfactorily. During this maintenance period, the Contractor shall be required to do regular
grass cutting as and when instructed by the Engineer.
S4/3 MTECH CONSULTANTS
3. Turfing and Tree Planting (Cont'd)
Tree Planting
The Contractor's attention is drawn to the current requirements of planting of trees laid down by
the Parks and Recreation Department (Ministry of National Development) which are to be
complied with wherever applicable. The standards of the planting, aeration and maintenance of
trees may be obtained from the Parks and Recreation Department.
Tree-planting pit shall be at least 1 x 1 x 1m deep. Backfill shall consist of three parts of good
excavated soil and one part of sludge fin and packed around the plant.
The Contractor shall protect the plant by erecting a temporary fence with a minimum height of
1.5m consisting of barbed wires at 150mm c/c wound around five 90mm diameter bakau or
bintang poles driven 600mm into the ground.
The Contractor shall tend and water the trees after planting, including weeding as necessary until
the trees starts to thrive. Any tree that fails to thrive shall be replaced by the Contractor at his
own expense.
All trees planted shall be warranted to thrive for a period of one year from the date of completion
of contract. Trees that failed to thrive shall be replaced at the Contractor's own expense and shall
be subjected to a further warranty of one year from date of planting.
Where directed by the Architect, the Contractor shall not cause any damage or harm to existing
trees or plants which are to be preserved.
During the maintenance period, the Contractor shall be required to maintain the trees, plants,
hedges and all turved areas in optimum growing conditions including:-
(a) removal of dead turves and weeds twice a month
(b) cutting of grass, trimming and pruning trees, plants and hedges once a month
(c) fertilizing, watering and maintaining plants in healthy conditions
4. Aprons
Generally aprons around building and connecting covered ways, etc. shall be of in-situ concrete
laid on a prepared bed of hard-core to thicknesses and dimensions as detailed on the drawings,
reinforced where required or if directed by the Engineer with a layer of an approved fabric
reinforcement. The top of concrete apron shall be finished smooth with a wood float to receive
tiles or paved with cement and sand (1:3) paving of the thickness shown on drawings or as
directed.
Expansion joints shall be provided in concrete aprons at suitable intervals or in positions detailed
on the drawings or as directed by the Architect.
S4/4 MTECH CONSULTANTS
4. Aprons (Cont’d)
Apron paving slabs, where required, shall be precast concrete slabs of the thickness shown on
drawings or as directed, cast in varying sizes to suit width of aprons, finished fair on exposed
faces, laid to falls on prepared bed of sand with joints grouted and pointed in cement and sand
mortar (1:3) and exposed edges next to channels in cement and sand (1:3) and trowelled smooth
with rounded arises.
5. Road Works
General
All road work and its associated facilities shall be constructed in accordance with LTA Standard
Road Details for Street Works and its requirement, and to the drawings and other specification
provided herein.
Subgrade of Driveway
The finished level of subgrade shall be shaped and finished to the lines, grades and cross sections
as shown on the drawing. The subgrade shall be trimmed so that the level does not vary + 35mm
from the level shown in the drawing.
Compaction of Subgrade
Compaction of natural ground shall be to the required density for a depth of not less than 200mm.
For all earth fills the last 500mm layer of the subgrade below the granite base course over the
area shall be compacted to a density of not less than ninety five percent of the maximum dry
density obtainable using modified A-ASHO compactor test.
At the time of compaction of each layer, the moisture content of the material shall be adjusted so
as to obtain the degree of compaction specified. Water shall be added to material which contains
insufficient moisture for compaction. The added water shall be sprayed uniformly and thoroughly
mixed with material until a homogeneous mixture is obtained. Material containing excessive
moisture shall not be compacted until the material has dried out sufficiently to obtain the required
compaction.
The whole subgrade surface of the road shall be consolidated with a wheeled roller of not less
than 8 tons after the subgrade has been properly shaped and obtained and all unstable materials
removed therefrom and replaced with approved materials.
No sub-base material or granite base course material shall be laid on the driveway until subgrade
has been inspected and approved for the laying of the sub-base or base course materials.
The Engineer may require the test to be carried out at any location he deems necessary. The
decision of the Engineer shall be final.
Any material laid on the subgrade before the subgrade has been approved shall be removed from
the site at the Contractor's expense. Work shall be so arranged that the final shaping and
consolidation are carried out immediately before the foundation work so that the finished
subgrade shall not be adversely affected by the weather.
The base course of roads shall consist of 200mm compacted thickness of sledge granite blocks to
be hand pitched and properly rolled.
S4/5 MTECH CONSULTANTS
5. Road Works (Cont'd)
Sub Base Course of Driveway (Cont’d)
The grading of sledge granite block shall conform to the requirements described under the clause
Grading of Materials. Blinding to the top of base course shall be a mixture of 1 part lateriate to 3
parts of granite dust.
The base course shall be well rolled with road rollers of 10 tons until the stones do not creep or
wave ahead of the roller and until all granite blocks have firmly interlocked and a smooth
uniform surface of the correct levels and cross-section has been formed.
Any depression of 13mm or below a 3.0m long straight edge shall be remedial by loosening of
the surface, adding or removing the road metal as necessary and re-rolling.
Grading of Materials
Laterite
Laterite supplied by the Contractor shall be well graded material, suitable for road making
containing a good proportion of course material. The grading of the laterite shall fall within the
following limits:
B.S. Sieve % Passing
22mm 90 - 100
13mm 66 - 100
9mm 55 - 87
5mm 35 - 60
No. 7 30 - 50
No. 14 28 - 46
No. 25 26 - 42
No. 52 23 - 38
No. 100 22 - 34
Before the commencement of the works three (3) representative samples of laterite shall be
submitted by the Contractor from each approved source of supply. The tenderer shall furnish
details in writing of such sources or sources of supply to the Engineer.
Such samples shall be truly representative of the material to be supplied and shall be required to
conform with the grading requirements as given in this specification.
S4/6 MTECH CONSULTANTS
5. Road Works (Cont'd)
Grading of Materials (Cont’d)
Laterite (Cont’d)
Where there is doubt as to the quality of the laterite being supplied at any time, grading tests shall
be carried out as and where required by the Engineer. All inferior laterite may be rejected. The
Contractor shall pay for the testing of all unsatisfactory samples.
Sledge Granite Blocks
Sledge granite blocks shall be hand picked from delivered loads of blocks ranging from 230mm
down to minimum 75 mm but majority of blocks must be 230mm to 150mm and infill gaps with
smaller sizes. An excess of flat granite shall not be used.
Granite Spalls (75mm to 40mm)
Broken stone or granite spalls shall extraneous matter. No particle is to to be such as no void will
be left The following is an approximate grading: be hard, durable, clean and free from exceed
75mm in size and the grading is after rolling with a 10/12 ton roller. The following is an
approximate grading:
B.S. Sieve % Passing (by weight)
75mm 100
40mm 85 - 100
9mm 40 - 70
5mm 25 - 45
No. 25 8 - 45
No. 200 0 - 10
Granite (40mm to fine)
Broken stone shall be similar to as described in the preceding paragraph.
B.S.Sieve % Passing (by weight)
50mm 100
40mm 95 - 100
19mm 45 - 100
9mm 35 - 100
5mm 25 - 100
S4/7 MTECH CONSULTANTS
5. Road Works (Cont'd)
Grading of Materials (Cont’d)
Granite (40mm to fine) (Cont’d)
B.S.Sieve % Passing (by weight)
No. 25 8 - 65
No. 52 5 - 40
No. 200 0 - 10
Wet Mix Asphalt Paving (Asphalt Concrete)
Generally
The Contractor shall lay 25mm premix asphaltic wearing course (Mix No. W3 and W4) on
prepared roads surface as specified in Table 4.
Binder
All bitumen shall be approved asphalt bitumen of either 60/70 penetration and/or 80/100
penetration (measured at 43o
in both cases). All bitumen shall be straightrun prepared only by
the refining of asphaltic-base petroleum and such refining shall not involve the "cracking"
process. No mineral matter other than that naturally contained in such bitumen shall be present.
The bitumen shall be of uniform quality, free from water and shall not foam when heated to
195o
C. The Contractor must state the country of countries of origin of all bitumen supplied, and
the price paid for such bitumen prior to its use in the works.
All bitumen to comply with the requirements given in Table 1 below:
TABLE 1
Item
Description
60/70
Penetration
Grade
80 - 100
Pentration
Grade
1.
Penetration at 43° 100 gms 60 - 70 80 - 100
2. Flash Point Cleveland
Open Cub)
250°
(Min)
236°
(Min)
3. Loss on heating for 5 hours 1%
(Max)
1.5%
(Max)
4. Penetration after loss on
heating 43° C
100 gms (5 seconds)
70% of Original
Penetration
70% of Penetration
(Min)
S4/8 MTECH CONSULTANTS
5. Road Works (Cont'd)
Wet Mix Asphalt Paving (Asphalt Concrete) (Cont’d)
Binder (Cont'd)
All bitumen to comply with the requirements given in Table 1 below:
TABLE 1
Item
Description
60/70
Penetration
Grade
80 – 100
Pentration
Grade
5. Ductility at 43° at 5 cm
per minute
90 cm
(Min)
30 cm
(Min)
6. Solubility in Carbon
Tetrachloride
99.5%
(Min)
99.5%
(Min)
Tests for the above properties shall be carried out as far as practicable in accordance with the
methods set out in the current edition of "Standard Methods of Testing Petroleum and its
Products" as issued by the Institute of Petroleum.
Mineral Fillers
Mineral fillers shall consist of Portland Cement to BS No. 12 of 1958, and/or granite must of
appropriate grading. At least 85% of cement filler and/or granite dust filler shall pass a No. 200
B.S. sieve and filler shall be thoroughly dry and shall be free from organic matter and clay
particles.
Fine Aggregate
This shall consist of approved clean, well-graded, fines produced in a secondary crushing plant,
or approved clean natural sand property washed, free of all impurities.
The grading shall comply with the requirements given in Table 2 below for wearing course
mixtures:
TABLE 2
GRADING OF FINE AGGREGATE
PASSING B.S. SIEVE
WEARING COURSE MIXTURE
Percentage by Weight
5mm 100
S4/9 MTECH CONSULTANTS
5. Road Works (Cont'd)
Wet Mix Asphalt Paving (Asphalt Concrete) (Cont’d)
Fine Aggregate (Cont’d)
TABLE 2
GRADING OF FINE AGGREGATE
PASSING B.S. SIEVE
WEARING COURSE MIXTURE
Percentage by Weight
No. 7 95-100
No. 25 75-95
No. 72 15-60
No. 200 0-3
Coarse Aggregate
Coarse aggregate shall consists of clean, well-graded, crushed granite of approved quality, free
from an excess of flat, elongated deleterious materials, and free from an excess of flat, elongated
or weathered pieces. Coarse aggregate for the purpose of this Contract, shall be taken as all
material retained on a 3mm British Standard Sieve.
The grading of the coarse aggregate shall comply with the requirements in Table 3 below for
wearing course mixture.
TABLE 3
GRADING OF COARSE AGGREGATE
PASSING B.S. SIEVE
NOMINAL THICKNESS
38mm - 44mm
Percentage by Weight
51mm -
38mm -
25mm 100
S4/10 MTECH CONSULTANTS
5. Road Works (Cont'd)
Wet Mix Asphalt Paving (Asphalt Concrete) (Cont’d)
Coarse Aggregate (Cont’d)
The grading of the coarse aggregate shall comply with the requirements in Table 3 below for
wearing course mixture.
TABLE 3
GRADING OF COARSE AGGREGATE
PASSING B.S. SIEVE
NOMINAL THICKNESS
38mm - 44mm
Percentage by Weight
19mm 85-100
13mm 0-100
10mm 0-100
6mm -
No. 7 0-5
Asphalt Mixing & Delivery
The Contractor shall furnish the Engineer in advance with full details of all asphalt mixing
plant(s) to be used, including average output capacity, type, age, maintenance facilities and all
other relevant particulars required by the Engineer. The mixing plant to be used shall have an
average output capacity of not less than 20 tons per hour.
The approximate mix required shall comply with W3 and W4 of Table 4. Wherever considered
advisable, the Engineer may vary the specified proportions of coarse and fine aggregates within
the range of + 10% and the Contractor shall NOT be entitled to any extra payment nor suffer any
reduction in payment on this account.
The Engineer may vary the percentage filler to be use, within a range of + 2% and the Contractor
shall NOT be entitled to any extra or reduced payment of this account.
The Engineer may likewise vary the percentage of bitumen to be used, whereupon the price paid
for the work shall be adjusted by him in accordance with the change in bitumen content ordered,
based only on the net purchase price paid by the Contractor for the bitumen being used. If this
price is greated than the ruling nett purchase price of bitumen at the time of variation, then the
latter price shall be adopted for the purposes of calculating the value of any such variation.
S4/11 MTECH CONSULTANTS
5. Road Works (Cont'd)
Wet Mix Asphalt Paving (Asphalt Concrete) (Cont’d)
Asphalt Mixing & Delivery (Cont’d)
All aggregate of the requisite sizes and grading shall be throughly dried and fed at a temperature
of 167°C to 195°C into a mechanical mixer of approved type. An accurately registering
pyrometer shall be installed at a suitable point at the discharge end of the drier with a registering
device so located as to indicate clearly the temperature of the coarse and fine aggregate when
discharged. The bitumen shall be heated, in an approved type boiler, to a temperature of 153°C to
181°C, and shall thereafter be added, together with the required proportion of filler, to the coarse
and fine aggregated, and all ingredients shall be thoroughly and efficiently mixed together until
complete coating of all aggregate and filler with the bitumen has been achieved. The Engineer or
his authorised representative shall have access at all times to the asphalt mixing plant(s) and shall
be at liberty to take such samples of materials as considered necessary from time to time to verify
the proper operation thereof.
If is particularly important to avoid excessive heating of the bitumen binder as this will lead to
hardening of the binder and result in a shortening of the useful life of the pavement. In all case
temperature should be kept as low as is consistent with proper mixing and laying.
The asphalt, after proper mixing, shall then be discharged from mixer direct into a tipping truck
of suitable dimension, for transportation to the worksite. The temperature of the mix on arrival at
such worksite shall not be less than 139°C. The Contractor shall provide an adequate number of
accurate thermometers for checking the temperature of bitumen, hot mix, asphalt, etc. as directed
by the Engineer.
Vehicles used for transporting the asphalt shall be thoroughly cleaned free of all foreign materials
immediately prior to loading with asphalt. The use of dirty or otherwise unsatisfactory vehicles
shall render the load(s) of asphalt liable to rejection.
Spreading & Finishing
The Contractor shall furnish the Engineer in advance with full details of the mechanical
spreader/finisher to be used, including date of manufacture, model, whether tracked or wheeled,
previous usage, maintenance facilities, and all other relevant particulars required by the Engineer.
The mechanical self-propelled spreader/finisher shall be capable of laying an asphalt carpet of
not less than 3m width, and of being operated at varying rates of travel consistent with the rate of
delivery and the type of asphalt mixture to be laid.
On arrival at the site, the asphalt mix shall be tipped into the hopper of the mechanical
self-propelled spreader/finisher and shall thereupon be spread, levelled, tamped and finished to
correct profile, camber or cross-fall without causing segregation, dragging, burning or other
surface defects or irregularities. The Contractor shall follow the Engineer's instructions as to the
rate of travel of such machine at all times, and the spreader shall be operated at a uniform rate of
travel and the mixture shall be fed to the spreader at such a rate as to permit continuous laying,
insofar as the supply and site conditions allow.
The spreader/finisher shall not operate on any type of side forms, but shall employ mechanical
devices to adjust the grade and confine the edges of the asphalt to true lines.
S4/12 MTECH CONSULTANTS
5. Road Works (Cont'd)
Wet Mix Asphalt Paving (Asphalt Concrete) (Cont’d)
Spreading & Finishing (Cont’d)
Immediately after laying, and before rolling, the surface shall be checked and all irregularities
and defects in alignment, grade, texture, etc. corrected in an approved manner.
The surfaces, after final rolling, when tested with a straight-edge 3 metres long (placed parallel to
the centre line of the carriageway) shall show no depression greater than 10mm. Preliminary
rolling shall be carried out initially with a 2 to 5-ton roller, as soon as the asphalt mix has cooled
sufficiently to support such roller without lateral flow of the mix. Finishing rolling shall be
carried out with an 8 to 10 ton tanden roller or other suitable type of roller acceptable to the
Engineer as soon as practicable after the preliminary rolling and shall proceed until no further
compaction of the asphalt can be obtained. All rolling shall proceed at a sufficiently slow speed
so as to avoid pushing or shoving of the asphalt carpet. The rollers shall not remain stationary on
the warm asphalt carpet for any appreciable length of time. No oil shall be used on the wheels of
any roller to prevent adhesion of asphalt. Sections of newly compacted asphalt carpet shall be
protected from traffic for at least six (6) hours, or until properly hardened by cooling. The
Engineer's requirements in this matter shall be final.
All joints, both longitudinal and transverse shall be cut back square immediately prior to laying
of further asphalt in contact with such joints, in order to ensure proper bond. All joints shall be
finished uniform and true and free from depressions and projections of any description, and in
particular the asphalt carpet shall not form any discontinuity at the commencement or completion
points of the work.
All manholes, kerbs, channels and other projections against which the asphalt mix is to be laid,
shall be cleaned and a thin coating of bitumen emulsion applied prior to the laying of the asphalt.
The mixture shall be carefully tamped around and against all projections by means of hot tampers
of not less than 11.5 kgs. in weight and the finished surface left flush or, if required, up to a
maximum of 3mm above such projections.
Preparation of Surfaces
Prior to the application of any prime or tack coat or spreading of the asphalt on any surface, such
surface shall be thoroughly cleaned and dried, and kept free from any loose or otherwise surplus
materials. Adherent patches or foreign material shall be removed from the surface by the use of a
scraper of other suitable method. All waste materials removed from the surface shall be properly
disposed of forthwith by the Contractor, failure to observe these requirements may result in
payment being withheld.
Tack Coats
The Contractor shall supply and lay a suitable tack coat of bitumen emulsion at the rate of 1.800
to 2.900 sq. metres per litre, as directed, to any surface, immediately prior to the spreading of the
asphalt thereon, and after such surface has been thorouqhly cleaned and dried.
The bitumen emulsion shall be applied by means of approved type of mechanical sprayer only,
and shall be uniformly applied at the specified rate of application. Any excess or unevenly
distributed bitumen shall be forthwith removed from the road surface at the Contractor's own
expense.
S4/13 MTECH CONSULTANTS
5. Road Works (Cont'd)
Wet Mix Asphalt Paving (Asphalt Concrete) (Cont'd)
Sampling & Testing
Samples of asphalt mixtures shall be taken as, when and where considered necessary, by the
Engineer, and testing shall, as far as practicable, be in accordance with British Standard 598 -
Methods for the Sampling and Examination of Bituminous Road Mixtures.
The cost of sampling and testing shall be borne by the Contractor and where test results are
unsatisfactory, the Engineer may condemn all the asphalt represented by such unsatisfactory
sample (s), or alternatively may, at his discretion, reduce the payment to the Contractor for such
asphalt in accordance with the degree of departure of the test results from those required by this
specification.
The Contractor or his representative shall be entitled to be present during the carrying out of any
tests, provided he shall have given one day's clear notice, on each occasion of such intention.
The test results shall satisfy both the following requirements:
(i) The percentage (%) of soluble bitumen in the mix of any and every sample should not be less
than the minimum percentage specified.
(ii) The average percentage of soluble bitumen of all the samples tested should also be not less
than the average percentage specified.
(iii) Where any of the test samples fails to comply with the requirement (i), all the asphalt
surfacing represented by such unsatisfactory samples will be reiected and no payment shall be
made.
(iv) Where the samples fail to comply with the requirement (ii), a reduced payment for such
asphalt surfacing shall be made to the Contractor. The amount of deduction will be decided by
the Engineer based on the content of bitumen. The Engineer's decision shall be final.
6. Kerbs
Precast concrete kerbs 300 x 100 x 900mm long in Grade 20 concrete shall be laid in cast-in-situ
concrete foundation backing in Grade 20 concrete at edge of driveway and road with top of kerb
100mm above proposed finished level of road. Joints between precast kerbs shall be filled with
cement mortar. The horizontal alignment of the kerbs shall not deviate by +-12mm from that
shown in the Drawings nor deviate from the straight by more than +-3mm in 3 metres length.
7. Channels around Buildings and Outfall Drains
Surface water channels around buildings, covered ways, etc. shall be of in-situ or precast as
shown on the drawings or as directed and finished internally and on top with 20mm thick cement
and sand (1:3) trowelled smooth. Channels shall be laid on a bed of prepared sand or hard-core
and where required, or if directed by the Engineer, reinforced with a layer of an approved fabric
or rod reinforcement. Layout of channels shall be as shown on the drawings with all bends and
junctions being carefully made to allow smooth and even flow. Minimum depth of channels shall
not be less
S4/14 MTECH CONSULTANTS
7. Channels around Buildings and Outfall Drains (Cont’d)
than 150mm and minimum falls not less than 1 in 180 unless otherwise stated on the drawings to
suit site conditions.
Composite channel drain shall be approved precast concrete 'V'-shaped composite drains, with
half round inverts and sides of the sizes as shown on the drawings and cast in 600mm lengths
with 50mm diameter weep hole in each side of each length and laid to fall on a bed of sand of the
thickness shown on the drawings with joints grouted and pointed in cement and sand (1:3).
The composite channel drains shall be laid to the lines and depths as shown on the drawings and
Grade 15 concrete lining shall be laid to the revetments above the tops of drains.
Precast concrete cover slab of the sizes shown on the drawings shall be laid over surface water
channels, cast in 600mm lengths with notched hand holes at both ends and reinforced with one
layer of an approved fabric reinforcement. Cover slabs shall be set in rebates properly cut to left
in the channel sides.
8. Construction of Precast Concrete Drains, Pipes and Culverts
The roadside drains shall be constructed section by section as directed by the Engineer and shall
be generally completed before commencing work on the carriageway and kerbs. The precast
units and sections shall be true to shape and of correct dimensions, finish and strengthened with
required reinforcement wherever required. All precast units shall be approved for use by the
Engineer before they are incorporated in any part of the works. Precast channels, pipe, revetment
slabs, etc. shall be properly laid, bedded on a sand base at least 75mm thick unless otherwise
stated and joints pointed with cement mortar. Side connections where required or shown on the
drawings shall be formed and secured in concrete and/or cement mortar as directed and shall be
finished to a smooth and uniform appearance. All precast drains, pipe and culverts shall be laid
to a gradient as indicated on the drawings or as directed by the Engineer. Box culverts shall be
laid on a sand base of at least 150mm thick compacted and screed off to the required level unless
otherwise indicated on the drawings.
9. Surface Water Drains
Construct surface water drains along the sides of buildings, roads, etc. as shown on the drawings,
constructed of 150mm thick sides and bottom with half round inverts and reinforced as detailed
and rendered inside and on exposed surfaces with cement and sand (1:3) 19mm thick. Construct
all necessary bends, junctions, etc.
On completion clear all debris and clean drain to ensure that the entire surface water drainage
system is in proper working order.
10. Scupper Drains and Pipes
Scupper drains and pipes shall be laid to the correct lines and levels from the kerbs to the
roadside drains and shall be properly connected in cement mortar to the openings in the concrete
kerbs and to the roadside drains. Revetment slabs and/or channels to the roadside drains shall be
broken to take the outlet ends of scupper pipes and the connections made good in cement mortar.
Each pipe
S4/15 MTECH CONSULTANTS
10. Scupper Drains and Pipes (Cont’d)
shall be properly bedded down and all butt joints sealed all round with cement mortar filleted up
to form a collar 50mm wide by 25mm thick.
Drop inlet chambers shall be provided at scupper pipe inlet along the carriageway all to LTA
Standard Road Details for Street Works and its requirement.
11. Test for Precast Concrete Culverts
The Engineer shall have access to the casting yard where the precast concrete culverts are being
manufactured. A copy of the manufacturer's test certificate shall be provided to the Engineer on
demand. The precast concrete pipe culvert shall be test to SS 183.
12. Grating, Manhole Cover and Frame
All gratings over drains including framing shall be constructed as shown on the drawings. They
shall be of hot-dip galvanizing in accordance with SS117: 1975.
The manhole covers and frames shall be of the ductile cast iron machined type and of approved
size, weight and pattern. The heavy duty type shall be used in roadways and paved areas.
Manhole covers and frames are to be set in cement mortar and surrounded with Grade 20A (Class
A) concrete and covers left flush with the surrounding ground or road surface as the case may be.
Care shall be taken to ensure that the cover is level with and sloped to any fall or grade in the
surrounding surfaces.
Manhole covers and frames shall be supplied coated with a black bituminous composition.
13. Gate
Provide and hang gates and gate posts in positions and to details as shown on the drawings.
Prepare, prime and paint one undercoat and two finishing coats enamel paint on surfaces of gates.
14. Chain Link Fencing
Provide galvanised chain link fencing 1,800mm high, consisting of No. 9 gauge x 50 x 50mm
mesh pvc-coated chain link mesh and screen/slats with 3 lines of No. 5 gauge galvanised
straining wire to match existing. The fencing shall fix to 63 x 63 x 6mm thick galvanised steel
angle post at 3.0m centres and 38 x 38 x 6mm thick painted galvanised steel stay at alternate post,
which is set in concrete footing.
CT1401B001 ANNEX B
PROGRAM SCHEDULE Page 1 of 1
PROGRAM SCHEDULE Contractor to submit a final program schedule and subject to SAS approval before commence work. Construction Period from date of award is not to exceed 5 months but can be extended with SAS’s approval. The attached program schedule is for guidance only.
CT1401B001PROGRAM SCHEDULEANNEX B
SATS TRANSSHIPMENT DEVELOPMENT PROPOSED CONSTRUCTION PROGRAMPROPOSAL 1A - WITH SHELTER (CONSTRUCTION PERIOD: 5 MONTHS)Date : 16-Jan-14
Note : For Full Works with Shelter
ITEMS
A TENDER AWARD
B1
a. Site Survey and Services Detection
b. Site Setting Up
c. Application of Permit to Commence Works
2
a. Site Clearing, Backfilling & Pegging Out.
b. Services Works, Diversions, New Lines
c. Foundation Works
d. Steel Works
e. Roof Works
f. Finishing Works including Services
g. External Works
3
a. Authority Inspections
b. TOP & CSC
3 4 1 3
CONSTRUCTION
Construction Works
Completion & Inspections
Preliminaries and Site Preparation
23 4 2 3 4 1 21 231 1Mth 3 Jun 14 Mth 4 Jul 14 Mth 5 Aug 14Mth 1 Apr 14
2 3 4 1 2Mth 2 May 14
4Mth 7 Oct 14
1 2 3 4Mth 6 Sept 14
4
WITH SHELTER Page 1