Housing in Developing Countries – Areas of Concern

1. Severe shortage of houses in developing countries specially for

poor people.

2. Severe problem of management of agro industrial waste in

developing countries.

3. Mounting pressure on non renewable energy resources. Non-

availability of energy efficient technologies for converting agro

industrial waste and renewable local resources into alternative

materials.

4. Expensive & scarce building materials and components

•Need for energy efficiency and environmental protection in manufacturing technologies.

• Need to develop cost effective construction technologies to mitigate the effects of natural hazards.

• Need to create employment and skill improvement opportunities leading to poverty alleviation.

• Need to substitute expensive & scarce building materials and components by low cost locally available

materials to suit local design typologies.

Housing in Developing Countries – Areas of Concern

Major Causes of High Building Costs

• Expensive materials• Lack of necessary building skills• Lack of guidelines in selection of appropriate building packages• Designs• Materials• Methods • equipment

Low Cost or Cost Effective Housing

• Aims to reduce the cost of construction and at the same time not sacrifice any element of safety or serviceability of the house over the life cycle.

• strong,• durable,• functional,• aesthetic,• environment friendly,• ecologically appropriate,• energy efficient • affordable and adaptable• cost-effective materials• appropriate technologies in construction

Various aspects for cost reduction

• Optimisation of land use• Functional design of buildings• Optimum use of building materials• Rationalisation of specifications• New construction materials and techniques

Technology Selection Criteria

• Saving in cost, initial as well as recurring.• Saving in consumption of imported or scare materials,

even if no saving in cost is achieved.• Saving in time of construction.• Utilization of waste materials even if no saving is achieved.• Saving in quantum of skilled labour even if no saving in cost is achieved.• Achieving better utilization of equipment but not necessary leading to optimum saving in cost.• Better utilization of space.• Better layout for economy in external services

Bamboo as a Material for Housing and Buildings – Indian Experience

Characteristics affecting usefulness of bamboo as construction material

- the strength of bamboo culms- their straightness- lightness combined with hardeners- range and size of hollowers

with good physical and mechanical properties, low shrinkage and average density, it is well suited to replace wood in several applications

Major Uses of Bamboo in Construction

• Scaffolding• Reinforcement• Roofing• Walling• Doors & Windows

Bamboo – Nature’s Gift[A material for cost effective and

disaster resistant housing]

As a Raw MaterialProperties:1. High tensile strength2. Very good weight to

strength ratio3. Pressure tolerance upto

3656 kg/cm2

4. Easy to handle with simple tools

5. Renewable raw material

Building Material1. Environment

friendly2. Energy efficient3. Cost effective

Weaknesses1. Has short durability compared to wood2. High moisture and starch content3. Prone to fungi and beetle attach4. Service life of untreated bamboo 4-6

years in exposed conditions

Treatment & PreservationPreservation (Traditional methods):Curing; Smoking; Soaking; SeasoningChemical Treatment:Boric acid; Borax; Boron; (Dip diffusion or modified Boucherie processes)

Mechanical Process forCutting, slicing, knot removing and slivering

Mat weaving

from Slivers

Hot Processing

and Binding

Composite Building Materials

•BMBs, BMPB, BMCS•Bamboo Lumber•Sandwiched panel

•Bamboo based shutters•Bamboo flooring Bamboo House

Bamboo – Raw Material to Finished Product

Bamboo has lower natural durability against attack of fungi and insects

- requires treatment to increase durability -difficult to be treated by normal preservative methods in dry

conditions.- Best carried out in green conditions.

IS9096:2006 : Code of Practice for preservation of bamboo for structural purpose

Covers : Type of preservations,Treatment procedure for structural purposes like post, scaffolding, walls, trusses etc.

Preservatives Recommended

- Coal Tar Creosote- Copper – chrome - arsenic compositions- Acid- cupric – chromate composition- Copper – chrome- born composition- Boni Acid – boxes- Copper zinc – napthanate Abietates

Process of PreservationIS 401:2001 Code of Practice for Preservation of Timber

1. Surface application ( brushing, dipping)

2. Hot & Cold Method

3. Boucheire Process 5. Inter Nodal Injection

4. Diffusion Process

Structural Provision of Bamboo

Part 6 : Structural DesignSection 3: Timber and Bamboo: 3B. Bamboo National Building Code.

Material Specification- Physical and mechanical properties of 20 species of bamboo- 16 species found suitable for structural purpose and densified in Group A,B,C.

New Technology

Development

Pre-fab Double walled Composite House

Developed a technology for Pre-fab Double Walled Composite House with IPIRTI, Bangalore.Material used are Bamboo Mat Board for walling, BMCS for Roofing with steel framed structure .Salient features are ease in transportation, speedy erection at a reasonable cost. Most suitable for emergency structures during post disaster events.

Two Storey Bamboo Housing System

Developed the technology with IPIRTI, Bangalore using bamboo based components.Material used are Bamboo coloums, Bamboo grid walls, BMCS for Roofing, bamboo composite beams with steel and bamboo and bamboo composite slab.Development of this technology will enable construction of two storey houses in the bamboo growing regions.

Bamboo Mat Ridge Cap for Roofing

Developed the technology with IPIRTI, Bangalore for replacement of the present practice of using flat boards to avoid perforations.

Salient features are:Dimensionally stableReady & easy to fixNon permeableSuitable for wide range of roof angles.Compatible with BMCS.

Other projects completed in NE Region

Construction of 2 Cafeteria Buildings in Kisama, Nagaland.

Construction of 2 demonstration structures using bamboo based technologies in Shillong, Meghalaya

Organisation of number of training programmes on bamboo based technologies.

Preparation of detailed feasibility reports for production ofbamboo based components like BMCS, BMB etc.

Challenges ahead

• Increasing durability• Developing efficient

jointing system• Developing prefab

system• Developing composite

system to deal with natural hazards

• Growing bamboo of structural grade

• Setting up of more production centers

• Studying other bamboo which are available but not used in construction

• Capacity building of artisans

COST EFFECTIVE MASS HOUSING TECHNOLOGY

MONOLITHIC CONCRETE HOUSING FORM WORK

What are the Requirements of anEffective Housing System?

• Must be cost effective.

• Must be capable of a fast rate of construction.

• Must be adaptable to any structural design or architectural layout.

• Must produce high quality, durable and low maintenance structures.

• Must produce structures that are resistant to meteorological and/or seismic conditions.

MONOLITHIC CONCRETE HOUSING FORM WORK TECHNOLOGY

• Hand-held reusable aluminum formwork system for forming cast-in-place concrete housing.

• The System also controls the scheduling of the other trades involved in the construction; – steel reinforcement, – mechanical and electrical,– concreting.

MONOLITHIC CONCRETE HOUSING FORM WORK TECHNOLOGY

• Can be used for any type of housing from; low rise single or double storey housing, to walk-up apartments, to high rise towers.

• Can be used for any income level of housing from low income, to medium income, to luxury condominiums.

Features of the System

• Versatility

• Speed

• Quality

• Durability

• Cost

Versatility

• Architect is not required to change the building layout to suit the Mascon System.

• Capable of forming any type of structural design for any type of housing.

– Column & Beam Design– Loadbearing Wall Design

Versatility

• The System is unique in that it forms all of the concrete in a building including; – walls– columns – beams– floor slabs– staircases– balconies– window hoods– storage lofts

• No need for bricks, blocks or plastering.

Speed

• Multi-Storey Housing - structures are completed at the rate of four days per floor - regardless of floor size.

• Single or Double Storey Housing - structures are completed at the rate of one house per day.

• To increase the speed of construction, several “sets” of formwork equipment can be provided.

Quality

• Precision in fabricating the Mascon formwork results in accurate and consistent forming of the concrete.

• The quality of the concrete finish is the same regardless of whether the System is used for low cost housing or luxury housing.

Durability of Housing Units

• All concrete (walls, slabs, staircases etc.) are poured monolithically, therefore, there are no construction joints and no problems of leaking joints.

• The result is a rigid reinforced “box” structure that is structurally very durable and very resistant to meteorological and seismic conditions.

Why is this System So Cost Effective?

• Highly reusable formwork.

• Forms all the concrete in a building.

• Unique construction cycling.

• Uses locally available materials - i.e. concrete and reinforcing steel.

• Requires unskilled labour only and no cranes.

• Loadbearing wall structural design.

Internal View of the Aluminum Formwork

Entire Four Storey Superstructure Completed in 16 Days

Each Double Storey House Completed at the Rate of One House per Day

Rigid & Strong formwork Panels Produce Smooth Off-form Concrete Finish

Square Openings Allow for Easy Fitting of Doors and Windows

Note - Surface Mounting of Electrical to Save on Costs

Electrical, However, is Usually Buried in Concrete with PVC Conduits

PVC Electrical Conduits for Floor Slabs

Unique Method for Propping of Floor Slab Formwork

Undisturbed Prop Head

Soffit of Floor Slab After Removal of Floor Slab Panels

Forming of Soffit of Staircase

For Low Cost Housing - No Internal Plastering Required - Only Paint

For Medium to High Cost Housing - A Thin (3mm) Skim Coat of Plaster is Applied Before Painting

For Low Cost Housing - No External Plastering Required - Only Paint

No External Plastering Required - Only Spray Applied Finish

Mascon Aluminum Forms are HandheldNO Need for Cranes

NO Need for Cranes for Concreting with the Mascon System as Concrete Pumps Can Be Used - Low Rise to High Rise

57

Innovative Building Technologies:

Hollow Interlocking-Compressed Stabilized Earth Block

(HI-CSEB)

58

Innovative Building Technologies:

Machine that produces HI-CSEB, developed by Auroville Earth Institute, Tamil Nadu, India

Aurum Press 3000

59

HI-CSEB

Economical/affordable, environmentally friendly, easily available, stronger, energy saving and simple to manufacture

Better Thermal Insulation

Warm in winter and cool in summer

Technical /Engineering Aspects

Block ProductionMaterial selection

Soil Identification – Top soil and soil with organic matter should not be used. Grain size distribution - more of sandy is preferred.

Gravel (mm) Sand(mm) Silt(mm) Clay(mm)

20 to 2mm 2 – 0.02 0.02 – 0.002 0.002 - 0

Some basic test for identifying the suitability of soil

• 15%gravel, 50%sand, 15% silt, 20%clayGranularity(Grain size

distribution test)

• Compress a moist soil by hand• Difficult to compress – gravely soil• Very easy to compress – Clayey soil

-Compressibility (Ease of the soil to be

compressed)

• Smells Rotten – lot of humus• Musty – humus• Agreeable smell – no humus - suitable for construction

Humus (presence of organic

materials0

• Difficult to break – clayey soil• Breaks easily – gravely soil

Plasticity ( Capacity to withstand

deformation)

• Wash the hand on which the soil paste was made• Soils grains does not stick on the palm – Gravely soil• Thin film of soil stick on the palm – clayey soil.

Cohesion(Property of the soil grains to remain together)

Proportions

• Cement : Soil (1 : 6)• Water content = 25 liters for one bag of

cement• Varying the ratio esp. the cement has the

proportionate cost involved • The ratio can go up to 1 cement to 10 soil

62

Same basic data on CSEB

Properties Values

Dry Compressive Strength @28days3 – 6Mpa (N/sqmm) ( +10% after 1 year,

20% after 2years)

Wet compressive strength @28days (3days immersion)

2 – 3 Mpa

Dry bending Strength @28days 0.5 – 1 Mps

Dry Shear Strength @28days 0.4 – 0.6Mpa

Density 1700 to 2000kg/cum

Water absorption @ 28days after 3 days immersion 8 to 12 % by weight

Energy Consumption 110MJ ( Kiln fired bricks = 539MJ)

Comparison with other building blocksProperties CSEB (HI - 245) Ordinary class III

brickConcrete hollow

blocks

Size 245x 245 x 95 195 x 95 x 75 390 x 190 x 190

Weight 8kg 3kg 16kg

Compressive strength (28days)

30 – 60kg/cmsq 35kg/cmsq 45kg/cmsq(approx)

Cost (Nu.) 13 per block ( 1:6 mix ratio)

11 per brick @ Thimphu

38.00 per block @ Thimphu

For a 250mm thick 1msq wall in a load bearing building @ ThimphuBlock Numbers Cost(Nu)

HI - CSEB 40(Approx) 520

Ordinary second class brick 166(approx) 1496.00

Hollow concrete Block 19.5(approx) 741

Block production machinesTwo Machines in the market

1) HI – CSEB Block machine – Habitech centre, Thailand

2) AURUM PRESS 3000 – Auroville,India Designer/ manufacturer Auroville Earth institute/ Aureka,

Cost of Press Rs 69,800.00

Cost of Mould ( 1 set) Rs 41,500.00

Max Blocks size 245 x 245 x 95

Compression force 150KN( 15 tones)

Production capacity per day with 7 workers

500 Blocks (average)

Designer/ manufacturer Habitat centre , Bangkok

Cost of Press 73,500.00 (Nu) 2008 rate

Cost of Mould ( 1 set) -

Max Blocks size 300 x 150 x 95

Production capacity per day ( 6- 7 workers)

500 average

Pilot House Construction – SQCA using HI – CSEB 245

• Two storied load bearing structures - serve as model for the earthquake resistant design features

• Sample Blocks test results

Soil sample source Average Compressive Strength Proposed construction site (1:8 mix

ratio

22 kg/cmsq

Buddha Dodema site ( 1: 8) 33 kg/cmsq

67

SQCA – Pilot Project

68

Hollow Interlocking –Compressed Stabilized Earth Block (HI-CSEB)

Some other buildings using HI-CSEB

69

Advantages

1. Use of cheap & locally available materials

2. Job opportunity for local people

3. Biodegradable materials

4. Energy efficiency and eco friendliness 5 – 15 times less energy consumed than fired brick and around 3 – 8 times less emission

5. Transferable technology

6. Import Reduction

7. 7. Cost effectiveness

8. 8. Minimum mortar required

9. 9. Keys that interlock with each other provides better integrity

10. 10. Hollow provisions for laying vertical and horizontal reinforcements to improve the lateral load resisting capacity

11. 11. Ease and Fastness in construction

12. 12. Fire resistant

Limitations

• Only for low rise structures: maximum 2 storey

• Strength very much dependant on the properties of soil

• Too much stabilization(cement) will make no economic sense

• Interlocking features do not provide air tightness. Minimum gap is formed due to which termite/air current can pass.