Relationship of strength reduction factor and maximum ductility factor for seismic design of one-storey industrial steel frames

In the earthquake-resistant design, it requires a check of the adequacy of the maximum inelastic deformation of structural members designed corresponding to the value of strength reduction factor, R, used for determining the design base shear and consequently equivalent static seismic forces applied on the structure. This paper presents evaluation of a relationship of the factor R and maximum ductility factor, D, for irregular building structures, particularly considered in this study for the case of one-storey industrial steel building frames with cranes by considering the effects of structural irregularities, seismic intensities and simultaneously horizontal and vertical seismic actions. In the evaluation, approximate equations were presented to determine the relationship which was characterized by the factor F. The relationship was evaluated by conducting a number of rigorous nonlinear inelastic dynamic time-history analyses of various one- and two-span analytical frames designed with various values of R = 2, 3 and 4 and maximum ground acceleration a = 0.25g, 0.5g and 0.75g. Based on the analytical results, the means and standard deviations of the relationship factor F for the analytical frames considered were presented by using approximation equations as well as Monte Carlo simulations. © 2020, Springer Nature Switzerland AG.