Investigation the effect of structural parameters uncertainty on the response of incremental dynamic analysis of intermediate steel moment resisting frame structures

There are several sources of uncertainty in the analysis and design of steel moment resisting frames, the random assumption of each of which can have a significant effect on the satisfiction of performance requirements of the structure. Among these factors, structural parameters can be mentioned, the most important of which are yield stress, modulus of elasticity, sections geometry and structural mass. Evaluating the impact of these factors depends on how the parameters are distributed and modeled. In this study, three common types of uniform, normal and log normal distributions for the parameters of mass structures, yield stress, modulus of elasticity and sections geometry that are random in nature are considered and using Monte Carlo method, the effect of uncertainty of these parameters is considered. The seismic performance of steel structures is investigated. Studies are performed on 4 structures of 3, 5, 10 and 15 floors of steel moment resisting frames with medium ductility, which are designed according to Iranian regulations. In order to model the structures and perform incremental dynamic analysis, Open Sees software was used .In order to evaluate the seismic performance of the structures, fragility curves were used. The results show that the type of distribution does not have a significant effect on the results of applying uncertainties. It is also observed that considering the mass uncertainty, increases the acceleration range in the Collapse Prevention (CP) and life safety (LS), which shows the significant effect of mass uncertainty compared to other parameters.