The author who lives in the UK urges the government to introduce his simple and feasible rapid system to build 100,000 new solid houses, for tsunami-afflicted people which could be done in 3-6 months. Repairs of damaged houses could begin with aid-materials from abroad. Work can also start in 1-2 weeks on the new houses by scientific project planning. Making wall-blocks can start straightaway. We need over 50 million of them, for new houses alone, irrespective of roof design.
It is vital that the government take correct steps in constructing houses for tsunami victims. For example to what designs are the new houses to be built? What material is to be used? How much? Are these available? Where? What can be done to prevent damage from possible future tsunamis?
Here are some urgent, strategic engineering solutions for immediate consideration of options and choices by top decision makers before preparing plans.
Mahadeva-rapid- concrete-houses system
This system enables the rapid building of small sturdy houses (even in 4-7 days) with concrete walls and semicircular concrete roofs, using precast-concrete wall and roof blocks.
A novel feature of this system is its precast reinforced-concrete arc-blocks (4-6 per foot run) are used to build roofs for main houses, outer kitchens and lavatories. They are usable even for wells. This system was devised and tried out firstly in Jaffna and Batticaloa districts in the early 1970s when the author's MITE organization built new model markets for Jaffna and Chunnakam.
The advantages of the above system are as follows:
*Speed of construction and occupation once precast blocks are ready;
*System is versatile, and enables the use of Intermediate Technology, with local raw materials, men and skills to construct houses, detached kitchens, lavatories, wells, school-classrooms, halls (with lintels), and so on;
*Unlike houses with perishable thatch and scarce timber, tiles, etc., these houses need little care for many years, being largely water-proof, gale-proof, fire-proof, thief-proof and tsunami-proof;
*They enable collection of clean rain-water, for cooking, etc., using plastic gutters and cisterns;
*Facilitates hygienic water-sealed lavatories, using underground septic tanks in rural areas;
*Simplicity and uniformity of their basic concept and design of components promote intrinsic economies of large-scale manufacture, overall time-saving, and ease of execution and management, especially when project planning techniques are used with many simultaneous jobs;
*Concrete wells can be sunk in 2-3 days each, on this system in areas of soft earth or sandy soil.
* This system can also provide open sheds for horticulture; underground water-storage tanks and bunkers; garages, holiday-chalets, etc, even for use by private individuals in the long-term.
One would assume that these houses would be too hot to live in. That is not so. The use of concrete grills at ground and high levels in end-walls will ensure continuous air circulation with cool interiors in the day. Warmth retained by walls and roofs combat any nocturnal cold breezes. The similar dome-shapes of the roofs and the grey colour of concrete may appear to run against cravings for individuality in occupants' minds. Yet this may be a real asset. Their uniformity of design can deter vain and wasteful human envies, boastings and fake prides-of-possession while skewing, different-coloured doors, and gardens can offer variety.
A typical small-scale house may be 10-12 feet wide and 15-20 feet long with short open verandahs in the front and back with a single semi-circular roof supported on concrete side-walls.
Ventilation and light are provided by concrete grills, up to 3 feet x 3 feet each, on every end-wall where doors are also located in front (and back, only if essential). The inside of the roof and walls are lime-washed, to disperse light, and to deter insects and germs.
The roofs are about 6 feet high on the sides and 11-12 feet in the middle. Internal lighting is with paraffin lamps or electricity. These houses are ample for small families of 2-3 adults and 2 children, most of whom would spend their day outdoors, at work, school, or in gardens. The houses may have similar-roofed detached water-sealed lavatories, outside kitchens, and wells -- if no other sources of water exist. Rainwater can be collected for cooking and drinking by using plastic gutters, down-pipes, and storage-tanks. Privacy could be enhanced by internal curtains. The floor is cement rendered. With this system larger houses, and skewing them at site for beauty, are viable.
Technical details
The arc-blocks are made in steel moulds to 2-6 feet radii enabling 4-12 feet wide structures/wells to be built. With properly made 1:2:4 (1/2" or 3/4") concrete no reinforcement is needed to strengthen the blocks but minimum steel rods or fabrics give added safety. The length of rooms may be virtually limitless, since the roof is built in lengths of one foot at a time, using 1:2 cement mortar to seal-up and strengthen the joints between the blocks. The ends of the blocks could also be designed to interlock with one another, strengthened further by the concrete mortar. The walls are built of precast concrete blocks to 4-6 inch thickness with up to 18" x 12" blocks.
Naturally the walls need foundations of 9"x15" wide, and 12"x24" depth, depending on the soil. These foundations themselves may be built using the same wall-blocks as above, placed suitably.
The floors may be made of compacted earth or sand, with ½"x1" rendering of 1:2 cement mortar. There is no need for any timber except for the doors, but these also could be pre-made with metal frames and tin or aluminium sheets (and painted in different colours, as the owners wish) to save available timber for repairing the damaged houses to match existing patterns.
The main materials in this system are locally available crushed stone, sand and cement. These can also be cheaply and quickly imported from neighbouring countries. Moulds for pre-casting wall-blocks can be of sawn-timber. The arc-roof-blocks need welded steel moulds. Construction scaffolding for roofs may be of jungle-poles or joinable/welded, iron-pipes/sections. Asbestos must be avoided.
