Centre For Green
Building Material and Technology

Development & Testing Of Beam For Double Curve Shell Roof 2009

Location: Bangalore Client: CGBMT

Full scale testing for House of Five Elements' double curve roof of 3500 sq. ft. concrete shell roof with a span of 8.5m-10m and length of over 45m, covers the core area of the house from east to west, with verandahs on both sides and a courtyard in between. The load testing of bamboo roof and other design tests were done by us on site before the final execution. It has been designed as a lightweight roof (2” RCC slab) with minimal reinforcement supported on two curved triangular Bamboo beams simply supported on bamboo columns of varying heights following the curve of the roof. A grid matrix of 1” bamboo splits at 6” centre to centre hold the screed concrete in place. It is based on the principle that “a material can bear more loads when it is curved”. Tarpaulin which is painted on one side is placed before concrete above the split bamboo mat, which acts as water proof member instead of plastic.