Analytical Study on Economic Effect of Grid Floor Geometric Parameters

Abstract

Timoshenko’s theory of plates is used to evaluate design moments and shears occurring in ribs of a Grid floor accurately. However, it involves assuming magnitudes of parameters like spacing of ribs, thickness of slab and width of rib which have considerable influence on the overall economy of the Grid floor. The aim of this study is to analytically find the effect of these assumed parameters on the overall economy of the structure. Grid floors of sizes 12 m X 16 m, 14 m X 16 m and 16 m X 16 m were designed for various dimensions of slab, rib and different spacing. The cost of each slab is estimated and interaction curves are developed. From this study, it can be concluded that the cost of the grid floor would be minimum if minimum thickness of slab, minimum width of ribs and maximum spacing of ribs is adopted. Further, for the typical case considered, the approximate method of Rankine - Grashoff theory underestimates the moments by around 20%.