Evaluation of the seismic sensitivity of steel frame with converging bracing to random variables

Document Type : Research Article


1 babol university

2 Civil Engineering, Babol Noshirvani University of Technology


Structural response to seismic load is one of the tasks of structural and earthquake engineers. Many factors affect the response of structures to seismic load. Seismic load, structural system, geometric characteristics and materials are examples that affect the response of structures to seismic load. The effect of each of these cases can be determined by sensitivity analysis. The purpose of this study was to evaluate the sensitivity of steel frame with converging braid compared to random variables under a seismic load. 10-story frame types with the convergent bracing system (four types) are analyzed after design and modeling using Monte Carlo and FOSM methods. Then the sensitivity of their response to random variables is evaluated. In this study, two-dimensional frames for sensitivity analysis were used. Also, the sensitivity analysis of the FOSM method is compared to the Monte Carlo analysis. The steel yield stress, the steel elastic modulus, the dead load, the live load, the damping coefficient and the length of the span are considered as random variables and their impact on the period of the structures, the maximum displacement of the roof and the maximum base shear have been investigated. The results show that the effect of random variables on the maximum Roof displacement is higher. The maximum sensitivity of the base shear to the random variables in the X convergent brace is more than the other structural systems, and the FOSM method has the least error in estimating the periodicity of the structures with the lowest error compared to the maximum roof displacement and the maximum base shear. The general results of the analysis show that steel yield stress, dead load, and damping ratio have the most effect on the response of steel bracing frames, so they should be carefully considered in structural calculations. This sensitivity is lower in live load, span length, and elasticity modulus of steel.


Main Subjects

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