Investigation of Fragility Curve of Mid-rise Sreel Moment Frame with Reduce Beam Section

In this study to determine the reduce beam section effect, on intermediate moment frame system behavior and its results, are discussed. For this purpose, non-linear static analysis is used. Generally, two types of structures have been selected in this study, the first 5, 10 and 15-story moment frame and the second with a cross section reduction in beam structures. Since this research has been done using software OpenSEES also to modeling reduce beam section, we used Krawinkler-Ibarra rotational spring model with concentrate plasticity on beams. After verification of RBS for a cantilever beam, this model has been extended to multi degree of freedom buildings. Finally different models have been subjected to incremental dynamic analysis and the results of analyzing the flexural structures of the frame and RBS structures have been used to calculate and extract the fracture curves of the structures and compare them. With respect to the fracture curve graphs of intermediate structures, the probability of colliding the IMF model with the RBS is higher.