EFFECT OF APPROXIMATION IN FRAME ANALYSIS

Abstract

The rapid growth of the urban population and consequent pressure on limited space have considerably influenced city residential development. Most of the residential buildings generally constructed are of low rise having height of up to four storeys because of the fact that it is unaffordable for a common man to go for high rise buildings. And people usually adopt the simple and approximate method of analysis and design of their building frames. So in the present study an attempt has been made to see the effect of approximations made during the analysis of up to four storey building frames. The present analysis has been done by both approximate methods and exact methods. Approximate analysis has been done by using subframe method for vertical load and portal frame method for horizontal loads. The exact analysis has been done by using STAAD III, a package for the analysis and design of building frames. Two, three and four storey building frame with four equal spans in longitudinal direction and two equal bays in transverse direction has been taken to find out the effect of storey. The effect of fixidity in the analysis of RC frame has also been made by considering various fixidities at the ground level. In addition to the above effects during the analysis of R.C. frames, the slab effect has also been considered to see its effects in the members. Slab effect has been considered in two different ways. One, by taking the rectangular beam as Tee beam according to the provisions of IS:456-1978 and another is by considering the slab as plate element.