FAILURE CRITERIA FOR NONLINEAR-ANALYSIS OF CONCRETE STRUCTURES

Challenges in designing complex concrete structures such as tall build ings, off shore oil platforms, nuclear containment structures have for ced the structural analyst to acquire a sound knowledge of the behavio ur of concrete. Many analytical studies of reinforced concrete structu res or members have been carried out using finite element method due t o the advent of digital computers and developments in constitutive mod elling to simulate the complex behaviour of concrete. In order to perf orm progressive failure analysis of a concrete structure and to trace the overall load displacement response upto ultimate state, suitable c onstitutive relationship including inelastic, failure criterion behavi our is required. The failure criteria for concrete under combined stat es of stress is defined in terms of yielding, initiation of cracking a nd loading functions. This paper critically examines and summarises th e salient features of the failure surfaces proposed by many investigat ors and explains the methodology in developing a failure criterion for the non-linear analysis. The proposed failure criterion is implemente d in the special purpose code FENLACS(1) and the results are compared with experimental results.