The need for affordable building technologies is obvious to most of us who come from countries that are poor and are often victims of natural calamities. Housing for the poor receives only limited funding and takes a backseat to other economic priorities. What the poor often do not realize is that there are no affordable technologies that can meet their need. The only way to meet their housing needs is to be an active part of the building process.
Professionals cannot afford to help them. Most technology experts such Architects and Engineers (AE) have to work for a paying client. The poor are not a paying client. Besides AE’s fee is tied to the cost of a building so the cheaper a structure the lesser the fee. The conflict of interest does not help. Funding by Government agencies for affordable housing is marginal or focused on services and utilities mostly realized as infrastructure development or so called “ site and services” project. So what ends up being passed as affordable building technology in the marketplace is a scaled down version of a handful of building systems albeit with modest finishes and compromised structure. In a nut shell when the technology morphs to affordable the walls do not get plastered, no plumbing or electricity is incorporated as a first exercise, and the reinforced concrete slab is replaced by corrugated metal roofing sheets which get unbearably hot in summer and cold in winter. More alarmingly very often the price has been reduced for the poor by removing critical structural and foundation specifications and details critical for seismic zones, flood zones, and zones which have poor soil conditions. Hence the disaster in Kashmir , AJK in 2005 when eighty (80%) percent of the housing stock was destroyed in a single earthquake.
So what is this new technology Membrane Assisted Seismic-Resistant Structures (MASS) that the author has developed and believes can make a difference. MASS in a nut shell is a non-combustible, insulated, light-weight soil-cement reinforced concrete wall and floor slab building system. It replaces wood, brick and concrete masonry unit (CMU) – currently the primary building block for walls.
How does it achieve the cost reduction and differentials that the buildings cost 50% less and by only using local resources. In a way it is not new. It is the old adobe (mud/clay) technology but a with new execution process. Which is why the technology can now compete with masonry and brick wall construction. There is no firing or baking, as in clay blocks to make brick, so MASS is environmentally less damaging and buildings have a much smaller carbon footprint. No wood is utilized so no further depletion of forests and timber stock. MASS and in a way adobe technology finally makes it possible to build much faster than brick or masonry – when it used to take twice as long previously. Adobe had its high poiint in multi-storied adobe structures in Yemen, Mali, Indian Pueblos of North America and other drier climate areas. But in the end it could not compete with masonry and brick structures in cost, time to execute, and maintenance issues.
The cost differential between MASS and masonry and brick structures is significant. MASS offers some 50% reduction in cost of building the walls and some 30% less in cost of the roof slab. Buildings get built in less than half the time. The new technology can also be utilized to build in all climate zones. The new technology also reduces operating cost as the structures are highly insulated and do not require supplemental cooling or heating for temperatures in the range of 40 degrees Fahrenheit to 90 degrees Fahrenheit. An example of such a building is a house made with “MASS” and commissioned by Aga Khan Foundation, see Fig. 1, which was built by the author in Kashmir, AJK some five years ago after a major earthquake hit the region. The structure has by now experienced several seismic (earthquakes) events of Richter 5.5 and higher. The quantity of cement utilized is eighty (80%) less than what would be utilized in masonry block walls for a house the same size. Yet its seismic response is better as it has a lower mass inertia and better energy dissipation and dampening characteristics. The interior can be modest see Fig 2 or high end, see Fig 3 & 4 completed in Mangla, Pakistan in 2011. The author has built all these structures in his presence using unskilled labor, materials bought in the local village markets, in Northern and Southern Pakistan.
The second technology developed by the author, patent pending, Versa-Slab (VS) slab, is a “Green” and sustainable alternative to the conventional reinforced concrete (RCC) slab. VS slab does not require any decking or scaffolding during the curing process. Hence finally countries that do not have wood, or cannot afford to destroy their timber forest, can build multi-story structures with concrete floor slabs that could not afford to do earlier. Floor slabs are fabricated at site using manual labor and with almost no mechanical equipment. As a footnote all the MASS built homes in AJK and elsewhere have experienced significant tremors and seismic events since their construction and do not exhibit any structural distress (i.e. cracks and failures).Views: 1269Share