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1.1

New Construction Techniques for M odern Housing Schemes

New Construction

Techniques for ModernHousing Schemes

Asoka Perera

Professor of Civil Engineering

Department of Civil Engineering

University of Moratuwa

1.2

New Construction Techniques for Modern Housing Schemes

• Background

 – Sri Lanka’s construction industry is yet to bebenefited from technologies developed for housing

 – Small scale applications are visible but largely theconstruction technology is reinforced concrete,bricks, blocks and other traditional methods.

 – However many other countries have implementednew housing technologies and getting the benefits.For example Government of Thailand have decidedto use pre-cast concrete methods to constructmore than 500,000 housing units to solve thehousing problem.

 – Similarly in India the use of new methods haveincreased.

 – Generally new methods are cost effective, fast,better appearance, better planned settlements anddurable.

OVERVIEW

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New Construction Techniques for M odern Housing Schemes

OVERVIEW

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New Construction Techniques for Modern Housing Schemes

OVERVIEW

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New Construction Techniques for M odern Housing Schemes

OVERVIEW

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New Construction Techniques for Modern Housing Schemes

OVERVIEW

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New Construction Techniques for M odern Housing Schemes

OVERVIEW

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New Construction Techniques for Modern Housing Schemes

OVERVIEW

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New Construction Techniques for M odern Housing Schemes

• The main pitfall – Many believe alternative materials or methods is

the way to reduce cost or to increase speedcompletely forgetting the design aspects.

 – The design aspects are very poorly addressed orcompletely ignored due to the fact thatArchitects, Structural Engineers and ServiceEngineers need to work as a team. Howevermain cost savings are in the area of design.

 – It is no doubt that new materials and methodscan be cost effective on top of the designaspects. Further alternative materials andmethods can address some pressing problemssuch shortage of river, shortage of skilled labour(or high cost) etc.

HOUSING TECHNOLOGIES :OVERVIEW

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New Construction Techniques for Modern Housing Schemes

• Three methods

 –Design methods, optimization programs etc.Structural Design optimization is a goodexample.

 – Alternative construction materials. Materials

such compressed earth blocks, fly ash blocksare good examples.

 – New construction methods. New slabconstruction methods, Pre-cast concrete

methods, Ferrocement methods

HOUSING TECHNOLOGIES :OVERVIEW

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New Construction Techniques for M odern Housing Schemes

HOUSING TECHNOLOGIES :OVERVIEW

Tec hnology P ossible Cost

savings

Implementation Challenges

1. D esign

methods

Structural Design

Services design

such as

electrical,

plumbing

Architectural

Design

Up to 30% savings

Up to 20% savings

Up to 20% savings

1. More design work 

2. No additional fee, in fact the fee could get

reduced

3. Lack of confidence

4. Lack of familiarity with design methods such as

masonry design.

5. Naturally would like to be extra safe

6. Bill is paid by the client

7. No mechanism to check or to challenge the

efficiency of the design. Very common system

character

8. May require the use of advance methods such as

value analysis  – A technique use USA military.

9. Getting and compiling technical information is

difficult.

10. Most popular may not the best.

11. Similar reasons of structural design.

12. Most difficult area for cost applications.

13. People buy Maruti cars as well as Benz cars

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New Construction Techniques for Modern Housing Schemes

HOUSING TECHNOLOGIES :OVERVIEW

Technology Possible Cost

savings

Implementation Challenges

1.Alternative Construction

Materials

Compressed Earth Blocks(CEB)

Waste related products such

as fly ash blocks

UPVC

Cement tiles

Up to maximum of 

20% cost savings.

Generally claimedas cost effective or

appear to be cost

effective but not

necessarily.

1.Compliance with existing standards.

Fore example CEB to comply with

BS5628.

2.Lack or non-existence of standardsparticularly for manufacture.

3.General resistance to new materials.

4.Lack of knowledge / information on

the new material.

1.New Construction

methods

Ex. Pre-cast concrete panels

New floor systems

Interlocking blocks

Rat-Trap Bond method

Up to a maximum of 

20%

1. Similar to new materials

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New Construction Techniques for M odern Housing Schemes

• Three methods

 – Most cost effective design method. For

example a masonry design could be 30% costeffective than reinforced concrete framearrangement. On the other hand for a buildingof 8 storeys reinforced concrete frame buildingcould be more cost effective than a masonrydesign.

 – Cost optimization within a design. Costoptimization can be done to find out the mosteconomical steel and section arrangementconsidering the prices of concrete, steel andformwork.

 – Use of value analysis for design of servicessuch as electrical work, plumbing etc.

HOUSING TECHNOLOGIES :DESIGN METHODS

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New Construction Techniques for Modern Housing Schemes

• Most Cost effective Design method

 – This could explain best with anexample. For example any house of twostorey and above can be taken. Theexample was taken form Tsunamihousing project in Ratmalana. Eachblock is consist of 8housing units andfour storeys

HOUSING TECHNOLOGIES :DESIGN METHODS

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New Construction Techniques for M odern Housing Schemes

HOUSING TECHNOLOGIES :DESIGN METHODS

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New Construction Techniques for Modern Housing Schemes

HOUSING TECHNOLOGIES :DESIGN METHODS

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New Construction Techniques for M odern Housing Schemes

• Most Cost effective Design method

 – The initial arrangement was typicalreinforced concrete frame buildingswith independent footings with plinthbeams, columns, beams and slabs.Table below shows the arrangementcost comparisons with masonry loadbearing wall structure.

HOUSING TECHNOLOGIES :DESIGN METHODS

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New Construction Techniques for Modern Housing Schemes

HOUSING TECHNOLOGIES :DESIGN METHODS

Element

Normal RC Design Masonry Design

Total Cost Total Cost

Footings in foundations 346,546.0 217,338.0

Plinth Beams 104,591.0 71,884.0

Rubble masonry infoundation 79,650.0 223,680.0

Columns 467,265.0 84,460.0

Beams 759,133.0 0.0

Walls 1,040,480.0 1,075,480.0

TOTAL 2,797,665.0 1,672,842.0

Net Saving 1,124,823.0

Saving % 40.2%

Net saving of the project 53,991,504.0

Total Estimate 429,600,000.0

Saving of the project % 12.6%

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New Construction Techniques for M odern Housing Schemes

• Elemental optimum Design :Example froma RC slab

 –

Slab also an expensive element in buildings.The optimum slab thickness is the one justsatisfies the deflection requirement and bestreinforcement arrangement is the one justsatisfies the bar spacing requirement (crackcontrol). However when spans becomes larger

the strength requirements supersedes theabove requirements.

HOUSING TECHNOLOGIES :DESIGN METHODS

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New Construction Techniques for Modern Housing Schemes

• Elemental optimum Design :Examplefrom a RC slab

HOUSING TECHNOLOGIES :DESIGN METHODS

Normal RC Design Optimum DesignTotal Cost Total Cost

Slab - Concrete 248,500.0 248,500.0

Slab - Reinforcement 264,504.0 186,960.0

Slab - Formwork 203,550.0 203,550.0

TOTAL 716,554.0 639,010.0

Saving 77,544.0

Saving % 10.8%

Total project cost saving 3,722,112.0

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New Construction Techniques for M odern Housing Schemes

• Earth Related Technologies

 – Compressed Stabilized Earth blocks

 – Adobe Blocks

 – Rammed Earth

• Other new methods

 – Straw bale method

 – Bamboo related methods

 – Waste related methods

• Interlocking blocks

 – Concrete blocks

 – Polystyrene interlocking blocks

ALTERNATIVE CONSTRUCTION MATERIALS

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New Construction Techniques for Modern Housing Schemes

• The use of compressed earth blocks inSri Lanka

 – First attempt in 1960’s with CINVA rammachines

 – Some houses were constructed in Colombo,Batticaloa etc.

 – Second attempt in 1980’s – NBRO building,

some in Gampaha

 – In 1990’s by University of Moratuwa – morethan 2000 houses.

 – There is growth of the application

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• The use of compressed earth blocks in SriLanka

• There are three manufacturers now.

 – One well established and have fairly good demand.The start was very difficult and project in Horanahelped to get established.

 – One has just commenced the production usingHydraform machine – a good machine but blocksseem expensive

 – One in Galle – planning to introduce plain blocks aswell as interlocking blocks using Hydraformmachine.

 – Some NGOs

 – Small scale manufacturers

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• The use of compressed earth blocks inother countries

 – India, There is wide usage mainly in Kerala,

Tamil Nadu and other places – Thailand – Initiatives of Habitec Centre

 – Australia

 – USA

 – Germany

 – France

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

SOIL BLOCK MACHINES

Soil:cement block machine Nature of projects Cost of Machine

1. CINVA ram machine

This is a very simple machine. Can be

transported from one project to the

other very easily. However

machine breaks quite often.

Suitable for self-help rural projects.

Good blocks can be made with

good quality controlling

measures

Rs. 15,000 (Normal

block)

Rs. 35,000

(Interlocking

block)

1. Auram Machines

Very good manual machines

manufactured in India. Two sizes

of machines are available. Moulds

are available to manufacture normal

blocks and interlocking blocks

Suitable to general building projects.

Machine ideal for setting-up of 

small-scale block manufacturing

yards too. The small machine

very suitable for the construction

of rural buildings

Rs. 170,000 (with all

options – three

sizes of blocks)

Rs. 90,000 (small

machine)

3.0 Automated hydraulic machines Large scale building projects and

setting-up of block 

manufacturing yards

Rs. 2.0 million – 

Medium

machines

Rs. 12 to 50 million

large machines

form USA and

China

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New Construction Techniques for M odern Housing Schemes

SOIL BLOCK MACHINES

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New Construction Techniques for Modern Housing Schemes

SOIL BLOCK MACHINES

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New Construction Techniques for M odern Housing Schemes

SOIL BLOCK MACHINES

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New Construction Techniques for Modern Housing Schemes

SOIL BLOCK MACHINES

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New Construction Techniques for M odern Housing Schemes

SOIL BLOCK MACHINES

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New Construction Techniques for Modern Housing Schemes

SOIL BLOCK MACHINES

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New Construction Techniques for M odern Housing Schemes

• Standards for Earth Construction

 – Sri Lanka now has a standard forCompressed StablizedEarth Blocks

 –

The use of provisions given in BS5628 –Standard for masonry, this will cover wall

construction but not the manufacture ofearth blocks but does not cover themanufacture of blocks

 – There is an Australian code of practice

 – There is an appendix to the building code ofUSA

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• The Indian for manufacture ofcompressed earth blocks

 – Specify the sizes of blocks, 300X140X100,

240X240X100, 250X110X100 – Specify the compressive strength expected

from blocks, 2.5N/mm2 to 5.0N/mm2

 – General statements on machines for block

manufacture

 – General statements on manufacturingprocess

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• The use of provisions in BS5628

 – Full scale wall panels and blocks need to be

tested. – Results were observed at

• Load deformation behaviour of wall panels;

• Stress at 1st crack; and

• Stress at failure

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

Physical characteristics Specified limits

Dry density

Total water absorption

>1750 kg/m3

< 1 5 %

Dry compressive strength

Grade1: > 6 .0N/mm2

Grade2 : >4.0up to6.0N/mm2

Grade3 : 2.8 upto4.0N/mm2

(not applicable for interlocking blocks)

Wet compressive strength

Grade1: >2 .4N/mm2

Grade2 : >1.6up to2.4N/mm2

Grade3 : >1.2up to1.6N/mm2

(notapplicable for interlocking blocks)

Flexural strength (bending strength) > 0.5 N/mm2

Pitting depth (Erosion resistance)< 10 mm

Linear expansion of block upon saturation with water< 0.10%

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New Construction Techniques for M odern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• The Australian code of practice

 – It is available in the CD given

 – Let us go through the code

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• Manufacture of Soil cement blocks

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

1.Extraction of soil; 2 . Transportation of soil;

3.Screening of soil; 3. Measuring of soil and

cement;

4. Dry mixing of soil and

cement;

5. Adding of water for humid

mixing;

6. Moulding using a

machine;

7. Curing of soil:cement

blocks; and

8. Storing of blocks.

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New Construction Techniques for Modern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• We could use

 – SLS Standards –SLS1382

 – Machine manufacturers manuals

 – Published manuals – a good one in the CD – Let us go through a good manual –

Published by GATE

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• Block Types

 – Different types are available

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• Rammed Earth method

 – Houses can be constructed with full

rammed earth methods – It is much easier to first erect concrete

columns and then to rammed earth wall

using slip form method

 – Probably the best may be to first erectreinforced earth columns using interlockingblocks and then to do the rammed earth

walls

 – Forms could be purchased fromgovernment factory and private suppliers

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• Rammed Earth method

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

1.59

New Construction Techniques for M odern Housing Schemes

• Rammed Earth method

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• Rammed Earth method

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• Rammed Earth method

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• Rammed Earth method

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• Rammed Earth method

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for Modern Housing Schemes

• Rammed Earth method

ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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New Construction Techniques for M odern Housing Schemes

• Very widely used in India

• This is basically brick on edge

ALTERNATIVE CONSTRUCTION M ETHODS : RAT-TRAP BOND METHOD

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New Construction Techniques for Modern Housing Schemes

• Very widely used in India

• This is basically brick on edge

ALTERNATIVE CONSTRUCTION METHODS : RAT-TRAP BOND METHOD

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New Construction Techniques for M odern Housing Schemes

• Wide range of floor slabs are nowavailable for housing

 – In Sri Lanka ICC, NERD, University of

Moratuwa – Habitech centre has curved plans and

integrated concrete slab

ALTERNATIVE CONSTRUCTION METHODS :FLOOR SLABS

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New Construction Techniques for Modern Housing Schemes

ALTERNATIVE CONSTRUCTION METHODS :FLOOR SLABS

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New Construction Techniques for M odern Housing Schemes

• Pre-cast concrete door and windowframes

• Roof items – Pre-cast purlins• Steel roof structures for housing – you

will get more details during site visits

• Steel forms for staircases

• There are many more from Habiteccentre

ALTERNATIVE CONSTRUCTION M ETHODS :OTHER METHODS

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New Construction Techniques for Modern Housing Schemes

• Formwork systems for concrete wallsand slabs

• Polystyrene forms for walls• Sprayed concrete on polystyrene

boards

• Wide range of products are available forabove methods

ALTERNATIVE NEW CONSTRUCTION M ETHODS

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New Construction Techniques for M odern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

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New Construction Techniques for Modern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

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1.73

New Construction Techniques for M odern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are available

from Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

1.74

New Construction Techniques for Modern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are available

from Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

1.75

New Construction Techniques for M odern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

1.76

New Construction Techniques for Modern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

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New Construction Techniques for M odern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are available

from Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

1.78

New Construction Techniques for Modern Housing Schemes

• Formwork system – MASCON fromCanada – Similar systems are available

from Germany, India etc.

ALTERNATIVE NEW CONSTRUCTION M ETHODS

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New Construction Techniques for M odern Housing Schemes

• Polystyrene forms for walls availableform USA, Australia etc.

• Generally expensive

ALTERNATIVE NEW CONSTRUCTION M ETHODS

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New Construction Techniques for Modern Housing Schemes

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New Construction Techniques for M odern Housing Schemes

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New Construction Techniques for Modern Housing Schemes

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New Construction Techniques for M odern Housing Schemes

• Let us look at compressed earth blocks

PROCUREMENT OF TECHNOLOGY AND COST SAVINGS

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New Construction Techniques for Modern Housing Schemes

• Design methods

• Alternative construction materials

• Alternative construction methods

• Cost of setting out

SUMMARY

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New Construction Techniques for M odern Housing Schemes

THANK YOU