PLASTIC THEORY AS APPLIED TO BUILDING FRAMES

Abstract

The object of this study was to examine the beha-viour of frames in elastic and plastic range when tested , to collapse and also to see how far simple plastic theory is justified to ,be used in design with the assumption that full redistribution of moments are taking place in the frame:/(In simple plastic theory it is usual tp take stress strain curve of graph 3.1. It is assumed that the material is perfectly plastic beyond'.: the lower yield point. Because of the large ductile behaviour of mild steel beyond yield point it has always been taken for granted that required redistribution of moments can take place in a redundant structure to convert it into a mechanism without the ultimate strain of steel being exceeded. But theoretically, it can be shown that Baker's curve of graph 3.1 fails to provide the neces-sary hinge rotation for the required Moment distribution. However, due to strain hardening, the strength of the structure is found to be even more than given by simple plastic theory by assuming complete morfient redisLribu-tion. An attempt has been made to investigate the problem theoretically as well as experimentally. Chapter 1 is of introductory nature and deals • with the general treatment of plastic theory. Chapter 2