Palaces For The People
Friday, September 19, 2003
"Building decent houses for God's people"
Approximate cost estimate for one Habitat house (In Indian Rupees)
Stage of completion Materials used Rate Cost
Foundation level Sand one load 3000 .
Concrete One load 3500 .
Cement 30 Bags 4000 .
Steel 10 and 6 mm (400 kgs) 5000 .
Concrete 1/2 load 1500 .
subtotal = 20000
Wall level Sand one load 3000 .
Bricks one load 3000 .
Steel 10 & 6 mm (450 kgs) 6000 .
Cement 25 bags 3500 .
Electric pipes & wire 1500 .
labour charges 3000
subtotal = 20000
Roof level Sand one load 3000 .
Bricks one load 3000 .
Cement 18 bags 2000 .
Labour charges 2000
subtotal = 10000
Plastering, Flooring, Sanitary level Sand one load 3000 .
Cement 15 bags 2000 .
Rings, basin, pipes 2000 .
Flooring stones 2000 .
Labour Charges 1000
subtotal = 10000
Cost upon completion:
Total = Rs 60000
US$ exchange value = US$ 1,304.35
Current Exchange Rates
As of Sep 18, 2003, the exchange rates are:
45.996 India Rupees per United States Dollars
0.0217 United States Dollars per India Rupees
Low cost housing for Orissa’s cyclone hit areas
Christoph Luethi, firstname.lastname@example.org
Development Alternatives (DA) in collaboration with CARE India is currently implementing a rehabilitation project for 1400 households in the areas worst hit by cyclone in the state of Orissa.
The cyclone that hit Orissa on 29th.October 1999, has left over 10,000 people dead and damaged 1.9 million houses and 18,000 schools and colleges in 12 districts of the eastern Indian state. Orissa is the second poorest state in India with an average GNP of $ 38 per head.
The disaster relief operation that got underway at the end of 1999 also was to include the rebuilding of houses for the most destitute and hardest hit by the cyclone. In a community managed process involving intermediary organisations like DA and local implementing NGOs like AKSS, CARE is carrying out a unique rebuilding effort which will deliver large numbers of cyclone-resistant core houses using cost-effective appropriate building materials.
Core funding for the project comes from the British OFDA and DEC agencies and beneficiaries are expected to contribute sweat equity during the house construction process. The project is expected to rebuild 1400 homes, train 1500 village masons and expose over 30,000 households to the new building solutions.
The table below gives a breakdown of the costs involved for one house, including labour and material inputs. At Rs.29,000 / $632.- (Rs.2420 per m2) the core house is a good low-cost solution that provides protection from future cyclones. This cost is expected to come down further, once all building banks will be working at full capacity. Another added advantage of the building materials used: construction time is brought down to only 7 days (excluding foundation works).
Total costs for 1 housing unit as per the 1st set of 20 constructed houses in $632. Cost is expected to reduce as the delivery is streamlined. ...
The ACT members plan to build 1,500 such cyclone safe houses along with hundreds of traditional homes. The villagers build the houses themselves but LWS-India, UELCI or CASA provide essential building materials along with food for the villagers while they build the houses.
A "cyclone safe" traditional house costs less than a third of the price of the new brick houses, which the Orissa State authorities recommend. A basic traditional house costs about a quarter of a new brick house.
Box 1.4 Shelters save lives and livelihoods
On an October night in 1999, India's worst disaster in living memory engulfed the villagers of Kurantatuth in Orissa state. Windspeeds reached 300 kilometres an hour. Tidal waves seven metres high crashed inland. Whole villages vanished.
As warnings reached the local Red Cross office, volunteers went door to door urging people to evacuate. When visibility dropped to less than five metres, the rescue team tied a rope to a tree and ran it to the Red Cross cyclone shelter.
Before the tidal wave engulfed the village, over 2,000 people were squeezed into a structure meant for no more than 1,500. After the storm subsided, villagers looked out and saw nothing but water, and hundreds of floating corpses, among them the neighbours who had chosen to stay at home. Virtually nothing remained of Kurantatuth but the cyclone shelter.
Similar stories could be heard from Orissa's 22 other cyclone shelters, all built by the Indian Red Cross with German government support. According to the Orissa government they saved 40,000 people. Based on the shelter project's budget, that works out at around US$ 80 per life saved.
But numbers are just part of the equation. Between cyclones, Red Cross shelters provide a focal point for rural disaster preparedness, education, first-aid training and self-help savings groups run by local women – all inseparable elements of living with, and recovering from disasters.
Brick arch foundation
Rat trap bonded brick masonry
Stabilised and compressed earth block masonry
Interlocking cement stabilised mud block masonry
Precast/Hollow Concrete block masonry
Flyash-Lime-Gypsum (Fal-G) products (environment friendly, energy efficient and cost effective products)
Autocalved aerated Concrete
Cellular light weight concrete
Stone concrete block masonry
Precast brick panels
Precast RCC planks and joists
Funicular shells over edge beams
Ferrocement Channel/shell units
Micro concrete roofing tiles
Pyramidal brick Roof
Jack arch with bricks and precast RCC joists
Corbelled brick arch roof
Pre-cast RCC lintels
Doors and Windows
Pre-cast RCC door and window frames
PVC doors, window frames, shutters and partition panels
Moulded, compressed wood fibre doors
Timber substitute through agricultural waste
Particle boards and bamboo ply for panelling, false ceiling and partition panels.
Ferro cement water tanks can be manufactured in any shape and size at site.
IMPORTANT DESIGN PARAMETERS FOR BUILDING CONSTRUCTION
The cyclone affected are a covers most of the coastal belt of Orissa where the devastation has occurred because of three main causes:
(1) Very high wind velocity of the order of 250 km/hour (70 m/s) causing tremendous pressures and suctions on the building roof and walls resulting in their destruction;
(2) The storm surge upto 7.5 m height coming from the sea as a result of the high wind velocities, the water first flowing from the sea towards the land as a wall of water and then flowing out from the land to the sea taking away everything that came in its path; and
(3) Very heavy continuous rain producing flood conditions in the flat coastal plains, particularly in the basins of River. Baitarni and Budhabalang
In the reconstruction of houses all these parameters must be accounted for if the reconstructed buildings have to survive the cyclones in future.
SUGGESTED DESIGN CRITERIA
Safety from Water
(a) To save the population, their cattle and household possessions, the first priority will be to protect the buildings from the onslaught of water, whether from the sea or from the flood due to heavy rains. This could be done by raising the ground floor of the buildings in one of the following three ways:
(i) to choose the site on high grounds above the highest water level that could be reached during flood or during high storm surge and tide;
(ii) to construct the buildings on raised mounds so that their plinth level is above the highest water level; or,
(iii) to construct the buildings on stilts, again keeping the floor level above the highest water level.
The safest solution from this point of view will be to raise the base level of the whole village.
WIND PRESSURES ON BUILDINGS
DESIGN WIND SPEED AND PRESSURES
The design wind pressure at height z above ground level on a surface normal to the wind stream is given by
Pz = 0.0006Vz2
Where Vz = design wind velocity, m/s
Pz = design wind pressure, kN/m2
The value of wind pressure actually to be considered on various elements on aerodynamics of flow around buildings the windward vertical faces being subjected to pressure, the leeward and lateral faces getting suction effects, and the sloping roofs getting pressures of suction effetcs depending on the slope. The projecting window shades, roof projections at eave levels are subjected to uplift pressures several times the intensity of Pz. These factors play an important role in determining the vulnerability of given building types in given wind speed zone. For example. Fig. 4 shows the various cladding areas of building, which will have different pressure coefficients.
Figure 5 and 6 show typical effects of openings in the walls for a given angle of attack of wind a indicated; only one large opening in a wall cause very large internal pressure say +0.7pz which combined with external suctions will increase the wind effects on cladding and their connections immensely. A building with all windows and doors locked. will have zero or very small internal suctions or pressure <0.20 pz. If a room has openings distributed in all walls or at least in opposite walls and the overall porosity is less than 5%, the passage of air will cause only low internal pressure say only 0.2pz. Effects of wind uplift on roof projections can also be seen in Fig. 5 and 6. For a design pressures will be 1.5kN/m2 and 3.65kN/m2 respectively. The design pressures could be obtained by multiplying with the coefficient as given in Fig.5 and 6 for the specimen cases shown. For other dimensions of length, width and height and direction of wind, reference may be made to I.S.:875 Part 3-1987.
Table 3-Aerofoil Effect of Wind
Wind Speed m/sec. (km/h) Typical Movement
10-15 (36-54) Loose galvanised iron sheets fly
15-20 (54-72) Loose fibre cement sheets fly
25-30 (90-108) Loose concrete and clay tiles fly
30-35 (108-126) Roof sheets fixed to batterns fly
35-40 (126-144) Small aircrafts take off speed
40-45 (144-162) Roof tiles nailed to batterns fly
45-50 (162-180) Garden walls blow over
50-55 (180-198) Unreinforced brick walls fail
55-60 (198-216) Major damage flying derbies
60-65 (216-234) 75 mm-thick concrete slab fly
65-70 (234-252) 100 mm thick concrete slabs fly
70-75 (252-270) 120 mm thick concrete slabs fly
>75 >270 150 mm thick concrete slab fly
Orissa's Unnatural Disaster
UK - In the November '99 New Scientist, journalist Fred Pearce, environmentalist Vandana Shiva, and several coastal geographers attributed much of the death and devastation from India's October 1999 supercyclone to the destruction of India's coastal mangrove forests. Orissa's mangroves were cleared to make way for shrimp farms. India has lost more than half its mangrove forests in the past 40 years. The cyclone ripped the coastal state with 300-kilometer-per-hour winds. A tidal surge and torrential rains flooded up to 13 kilometers inland with five feet of water. Poor communities 50 kilometers from the coast were washed away. About 10,000 people died, and 10 million were left homeless. "In the past," says Tom Spencer of the Cambridge University Coastal Research Unit, "the mangroves would have dissipated the incoming wave energy." In addition to providing habitat and fish nurseries, mangroves trap sediment in their roots, creating shallow shorelines that slow waves, while their leafy canopies shelter the land from wind.
COPING WITH SOIL MOVEMENTS
Section I. Minimizing and Tolerating Soil Movements
6-1. General. Development of society leads increasingly to construction on
marginal (soft, expansive, collapsible) soil subject to potential volume changes.
Sufficient soil exploration and tests are necessary to provide reliable
soil parameters for evaluating reasonable estimates of total and differential
a. Exploratory Borings. Exploratory borings should be made within soil
areas supporting the structure and sufficient tests performed to determine upper
and lower limits of the soil strength, stiffness, and other required parameters.
Depth of borings should be sufficient to include the significantly
stressed zones of soil from overlying structures. These depths should be
twice the minimum width of footings or mats with length to width ratios less
than two, four times the minimum width of infinitely long footings or embankments,
or to the depth of incompressible strata, whichever is least.