Composite T-beam Roof: An Alternate Affordable Roofing System

摘要

The reinforced concrete slab is a universally accepted technology for roofing and flooring systems. In fact, in recent times, villagers in India have enthusiastically taken to reinforced concrete instead of tiled roofing. However, there are some disadvantages of RC slab which affects its affordability and ecological soundness. The problems may be listed as follows; (a) In RC slab of 12.5 cms thickness, the bottom portion of 6-7 cms will be under tension. Hence, the concrete using a high cement content remains cracked and ineffective. Its only function is to provide a good lever arm between the steel and the centre of compression, (b) Secondly, the in situ nature of concrete slab construction needs an elaborate and time consuming formwork to support the fresh concrete, (c) When the RC slab is used as a roof it picks up a lot of solar heat and radiates it into the interior for several hours after sunset. This can be especially problematic in hot and dry areas. An alternative to the RC slab must explore ways of replacing expensive concrete at the bottom by a less expensive and insulating material. The problem of formwork has to be solved by looking at partial or completely prefabricated components. This study deals with such a solution which may be named as the composite T-beam.