Nonlinear analysis of reinforced concrete frames considering the cracking effect

In this study, a computer program based on the iterative procedure has been developed using rigid diaphragm model for the three dimensional analysis of reinforced concrete frames with cracked beam and column elements. ACI, CEB and probability-based effective stiffness models are used for the effective moment of inertia of the cracked members. In the analysis, shear deformations which can be large following crack developments are taken into account and the variation of the shear rigidity due to cracking is considered by reduced shear stiffness models. The results of the computer program have been compared with the experimental data of tests on full-size structural subassemblages and found to be in good agreement. In the present study, a computer program has also been developed for the three dimensional analysis of reinforced concrete frames considering the geometrical nonlinearity and cracking effects in the analysis. The influence of geometrical nonlinearity and cracking effect on the behavior of reinforced concrete frames has been investigated. The most significant feature of the proposed iterative procedures developed in the present study is that the variations in the flexural stiffness of beams and columns can be observed explicitly. Keywords: Three dimensional analysis, reinforced concrete frames, effective moment of inertia, effective shear modulus, lateral deflections.