METHOD STATEMENT FOR RAFT CONCRETE TOWER T-1 :

Doc. No. 53-R3

METHOD STATEMENT

BACK FILLING

METHOD STATEMENT FOR BACK FILLING

Note: -This method statement is revision of Doc # 53 R-2. Revision of this method statement is due to the change in methodology of backfilling activity. This method statement will supersede Doc # 53 R-2. 1. Scope:This Method Statement will cover all back filling activities around the project site as per design/construction drawings provided by the Engineer.2. Back Filling in Confined Spaces:Sand Filling: -

Sand filling will be done in confined areas where space is too congested and there is not enough working space to use any type of plate compactor or other mechanical means that can be adopted for the proper compaction of backfilled material.

Procedure:- All the area to be backfilled with the sand will be properly cleaned from debris.

Proper approval of sandy material will be taken from the Engineer before starting any type of backfilling. Prior to the backfilling with sand the area will be sprinkled with water.

The sand will be put in layers and will be spread with the help of manual labour. Each layer will be soaked with water before putting the next layer.

The backfilling activity will be done under supervision of Engineers rep. and checked time to time. 3. Back Filling in Unconfined Spaces:(a) Earth Filling: -

Area, other than confined area, to be filled with earthen material that shall be approved by the Engineer prior to commencement of backfilling activity.(b) Location of Earth Filling: -

Areas along grid A-0, A, B & 0 shall be filled with stockpiled excavated material. (c) Type of Earth Fill Material: -

Earthen fill material used shall be of A-4 & A-24 category.

(d) Procedure of Earth Filling: -

i. Borrow Pit Location: -Earthen backfilling shall be done with approved material from the selected stockpile and excavated material with in free haulage limit of project boundary. Prior to backfilling the stockpiles to be approved by the Engineer for have the suitable material as per Engineers recommendations.ii. Mode of Transportation: -Excavators/ Power Shovels shall be used to transform large heaps of stockpile into loose material and after that it will be transported with the help of dumpers to transport the material from borrow pit to the required site area. iii. Methodology of Layers: -The material transported to site with the help of dumpers shall be put in the form of layers at suitable area. Layering shall be done with the help of excavator and leveling of the layers shall be done manually. Deep filling shall be predominantly granular material and free from slurry mud, organic or other unsuitable matter and capable of compaction by surcharge load. iv. Surcharge Loads: -The backfilling will be done up to design road level provided by the Engineer considering the top 1m meter as surcharge load over the backfilled area that helps in consolidation. This surcharge load will be kept for at least 6 months so that the underneath soil well consolidated to have further backfilling layer. While the preparation of roads this top 1m quantity will be removed a side and backfilled again through under mentioned procedure.(e) Provision of Road in Later Stages: -

In later stages, when road work will commence, following procedure shall be adopted to remove surcharge load and to carry out the roadwork as per the design. a. Compaction of Formation Level: -

After removing the surcharge load, the formation level will be achieved in layers, the backfilling will be done in layers of each 150mm well compacted with the help of rollers and other equipments like plate compactors, jumping compactors etc., to achieve required compaction. Each layer will be inspected by the Engineers rep. through proper inspection form submitted by the Contractor.b. Procedure: - 1. The area to be backfilled shall be inspected by Engineers Rep. (ARA-AC) before backfilling and contour plans showing existing levels to be verified by the engineer.

2. Material for backfilling from approved source shall be placed in layers not exceeding 150mm measured as compacted material.

3. The filling shall be compacted by mechanical means using plate compactor, roller etc. depending upon the space available for the suitable equipment.

4. Each compacted layer to be checked by Field Density Test. The samples will be collected by IJM QA/QC Engineer as per ASHTOO standards from three different locations on each side of building in the presence of Engineers representative. These samples will be sent to nearest laboratory for testing.

5. Filling around pipes and cables shall be carefully placed with sand to cover the pipe or cable completely before the normal fill is placed.

6. Backfilling of trenches/foundations shall be carried out only after the pipe line/structural works within the excavations have been inspected, tested and approved by the Engineer. Approved sand will be used to cover the services completely before the normal fill is placed.7. Before the start of fill and backfill, the contractor shall satisfy himself as to the levels and slopes of the fills and backfill shown on the drawings, the requirements of compaction, the possibility of settlement and all other particulars whatsoever in connection with the filling works.

8. All filled areas shall be left neat, smooth and well compacted, the top surface consisting of the normal site surface soil, unless otherwise directed.

9. Timing for backfilling/ compaction shall be coordinated with ARA-AC.

4. Tests: -

Following tests shall be performed on the final compacted layer of soil.

Proctor TestFor the selected borrow pit area a Proctor test for modified ratio will be performed by in presence of Engineers rep. to produce in-situ density not less than 95% of maximum dry density at optimum moisture content as per AASHTO T-180.

Field Density Test (FDT)

All the field density tests shall be performed in the presence of Engineer/Engineers representative.Safety Precautions

1. All safety precautions will be taken as not to harm any structures adjacent to backfilling area and as not to displace any pipes or conduits inside.2. All the workers will be instructed to wear required Personal Protective Equipments (PPE) during work in order to avoid any mishaps.3. All the related machinery will be properly maintained to avoid any oil leakage.

4. In case of any mishap, first-aid facility and a vehicle will be available at site at all times during concreting in order to provide proper treatment to the workers._____________

____________Prepared By: Checked By:Awais Imtiaz

Chong Food YouPlanning Engineer Project Manager

IJM Gulf Pakistan (Pvt) Ltd.

IJM Gulf Pakistan (Pvt) Ltd. IJM GULF

WORLD TRADE CENTER

DHA ISLAMABAD

IJM GULF

WORLD TRADE CENTER

DHA ISLAMABAD

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