Investigation on Improvement of Low Cost NERD Slab System

Abstract

The NERD center floor slab system was introduced by late Dr. A.N.S. Kulasinghe in early 1987 specially for domestic buildings which are used by middle income families in Sri Lanka. The invention of NERD system directed to identify cost effective slab construction system relative to conventional slab system and also the use of un-propped construction technique and reduction of depth of slab caused to reduce construction time and material required for construction activities. The NERD system consists with 50 mm thick in-situ concrete slab retain on trapezoidal shape pre-stressed beams which are placed by keeping 600 mm interval between each. Although, the concept of NERD system is being widely adapted in domestic building construction exposed beam under the soffit of the slab keeps away people from the use of NERD slab system. Therefore, this research has been given much more advertency to make it as flat soffit slab with the improvement of structural arrangement of the NERD system such a way that changing the shape of pre-stressed beam and thickness of in-situ concrete slab with hollow arrangement to reduce utilized concrete of the slab.