Introduction to MASS Technology
Two new proprietary building technologies, patent-pending, are promising considerable cost and schedule advantages over conventional building technologies. The two technologies called Membrane Assisted Seismic-Responsive Structures (MASS) and Versa-Slab (VS ) reduce the cost of construction; have passive heating and cooling capabilities; reduce the life-cycle and day-to-day building operating cost; provide for more resilient interior and exterior finishes; and are eco-friendly with a smaller carbon footprint. The two technologies have been developed by Javed Sultan, a licensed US based architect and a civil engineer.
The first technology MASS is a new method of wall construction. MASS wall system is a non-combustible, insulated, light-weight reinforced concrete pre-cast panel system. It utilizes light weight fero-cement panels for wall construction. It replaces wood, brick and concrete masonry unit (CMU) currently the primary building block for walls.
While walls can be built using either wood, masonry, or pre-cast panels, floor slabs are a much greater challenge.
The choice for slabs is generally restricted to cast-in-place reinforced concrete slab (RCC ), or some kind of horizontal diaphragm supported by wood or steel trusses. Wood and Steel trusses are expensive and the RCC slab option although more convenient and practical requires metal or wood decking, as well as wood and/ or steel pipes for scaffolding, in order to support the slab during the curing process. These temporary supports (scaffolding) required to support RCC slab during the curing process are expensive, impact the construction schedule adversely, and when wood is utilized for scaffolding are harmful to the environment.
The second technology VS slab, is a “Green” and sustainable alternative to the conventional RCC slab.
VS slab system do not require any decking or scaffolding during the curing process. Hence finally countries that do not have wood, or cannot afford wood, can build structures that they could not afford earlier. Additionally MASS/ VS are extremely flexible in allowing for both large scale industrialized and capital intensive production, as well as construction processes which require little initial capital investment and compelled to rely on non-industrial processes. In the later option all wall and floor slabs are fabricated at site using manual labor. The use of manual labor greatly benefits developing economies as it creates jobs and provides employment opportunities. In the above example of a single story home , see picture (Figures 2 and 3), a three room (plus bathroom and kitchen) affordable, earthquake-resistant structure was built using MASS technology in 2006-2007 time frame, one year after a major earthquake devastated the region. The above demonstration homes were built in Kashmir, Pakistan for the Aga Khan Planning and Building Services Pakistan (AKPBSP). All wall panels for the above homes were fabricated at site using manual labor, without the use of any mechanical equipment, in an area where utility and road infrastructure is minimal or non-existent. The cost at the time of construction was approximately fifty percent less than comparable homes constructed with masonry (CMU blocks).
All of the MASS built homes in AJK have experienced significant tremors and seismic events since their construction and do not exhibit any structural distress (i.e. cracks and failures).
MASS can also be utilized to build luxury homes and/or commercial buildings. The pictures (Figure 4, 5 and 6 ) show luxury homes under construction in Mangla, Pakistan using the same MASS technology. These homes have an average insulation value of R-24+ for walls and R-28+ for Roof Slab (Fig. 12). The super-insulated homes require less than fifty percent of cooling and heating of conventional masonry homes. Hence homes built with MASS are not only cheaper but are also energy efficient, less resource driven, and can be designed for extreme weather conditions including for extremely cold and hot climate zones as well as areas subject to high winds, tornados, cyclones and flood contingencies.
Wall System: MASS panels are installed quickly as seen in picture (Fig. 7). The picture shows wall being constructed for a luxury villa in Mangla, Pakistan. The panels are fabricated on site using local resources and manual labor, hence providing local employment for both the skilled (masons, carpenters) and unskilled (labor). This in turn stimulates the local economy. Additionally, on-site production of panels minimizes the likelihood of damage during transportation, thereby compromising the strength of the panels. Also transportation requires fossil fuels, which are becoming increasingly expensive. Furthermore, developing countries do not have the infrastructure, road and transportation systems, or the skilled manpower to permit utilization of conventional precast panel system.
Conventional pre-cast panels are very heavy, require a controlled factory environment for production, and generally require mechanical lifting usually with cranes. Also the panels are designed to strict specification and do not permit even minor deviations from specifications. MASS wall panels and VS floor slabs on the other hand allow a greater latitude for errors and omissions (E&O), without compromising quality or strength of the panels, and hence do not need a controlled factory environment or skilled manpower for their production. They are light weight, are fabricated at site by semi-skilled workers using hand tools, and manually lifted in place without the assistance of a crane or other mechanical lifting equipment. MASS is a far more robust and affordable alternative for most resource starved developing, as well as developed, economies. The detailing and installation of MASS panels are a lot simpler. There are none of the complicated anchors and embeds typical of conventional precast panel construction. Additionally joints between panels are easily interlocked or sealed, which can be complex and tedious with conventional pre-cast panels. The simple jointing details of MASS makes for a more water-tight wall panel system, thus permitting design for flood resistance. The panels can be finished as desired.
Floor System: VERSA (VS ) floor and roof slab system is a self-supporting floor and roof slab system. The VS pre-cast slab (RCC plank) is an alternative to the conventional RCC floor and slab system. In most countries, if not all, wood is the only affordable and practical decking and scaffolding material utilized to support RCC slabs during curing. This dependency on wood has resulted in large scale deforestation of timber forests. This deforestation is in turn one of the primary culprits behind global warming, soil erosion, ozone depletion and other environmental maladies. VS slab effectively eliminates all use of wood from the slab construction process. The pre-cast slabs are lifted into place by manual labor. The reinforced concrete VS slabs do not require any scaffolding or vertical support members during curing. The slab shown on Picture (Fig: 8 and 9) are eighteen (18) foot clear span self-supporting slab, which were lifted in place by laborers without the assistance of cranes or lifting equipment.
Additionally, the lag time (curing time) before work could start below the slab was eliminated, as there were no scaffolding in the work space below the slab, and hence work started in hours after the slab was placed. This accelerated the construction schedule significantly, resulting in lower construction costs and associated administrative and general condition costs. The picture (Figure 9) shows an eighteen foot span clear-span Versa Slabs panel on top of beams of the first floor of a home in Mangla, Pakistan. It was placed manually - without cranes or mechanical lifting equipment - in hours as opposed to weeks.
MASS is a state-of-the-art technology which incorporates tremendous advantages over conventional construction methods and techniques i.e. such as concrete masonry units (CMU), conventional pre-cast concrete panels, insulated metal panels, insulated blocks, or brick-RCC frame.
Reduction in Cost of Construction: This state-of-the-art technology allows for up to a 15% to 30% reduction in construction cost due to its unique design of structural elements (walls, roofs and slab). At the same time, these elements contribute to the overall strength of the building and make it more energy efficient.
Energy Efficiency and Construction Quality: Aside from the savings in the “first” cost of construction, MASS/VS offer significant savings in the long term operational cost associated with building heating, cooling, and maintenance. MASS wall and roof technologies require very little maintenance and are resilient to climate and environmental damage. With no mortar joints they are less prone to damages due to acid rain, salt water and other air-borne pollutants. Many Caribbean countries (Haiti, for example), as well as Sub-Saharan African countries, have lost most of their forest and timber reserves and are unable to construct due to lack of an affordable and ecologically responsive building material. For these countries MASS/VS offers a significant opportunity for affordable construction.
Structural elements: The depth of a VS slab is akin to the conventional five and a half inch (5.5 inch) RCC floor slab, with the added advantage of providing cavity in the slab for utility conduit. The deflection of the slab at a design load (live) with code specified factor of safety is maintained at one over six hundred (1/400) which is lower than code recommended allowable deflection. All tests are conducted in testing labs in the presence of licensed structural engineers
Architectural elements and finishes: MASS allows a broad range of finishes based on budget and affordability. The technology permits the design of non-linear surfaces thereby offering greater design flexibility. Niches and recesses, not easily possible with other building systems, are quite inexpensively and easily executed with MASS. The advantages of the wall system over other pre-cast techniques are also numerous.
The technology allows for rich interiors and both textured as well as smooth walls and ceiling as shown in picture (Figure 4,5, and 6). Application of veneer is very easy without the typical problems of de-lamination inherent with other technologies that use dissimilar materials (such as plaster on brick). The exterior of MASS buildings can have a plaster/stucco and/or a simulated stone (marble, granite, limestone) or brick . Pictures (Figures 10 and 11) are examples of the type of interior and exterior finishes that can be achieved with MASS.
Additionally all kind of finishes can be applied to the floor slab (including marble, granite, porcelain tiles); roof with clay tiles, over insulated roof slab see picture (Figure 12). Roof clay tiles can be subsequently placed and anchored to the composite insulated roof slab providing for a waterproof and aesthetically pleasing building.