Evaluation of current criteria in predicting the separation necessary to prevent seismic pounding between nonlinear hysteretic structural systems

This study evaluates the accuracy of four different criteria to calculate the separation necessary to prevent seismic pounding between nonlinear hysteretic structural systems. All of the criteria considered in this paper make use of the same basic equation of the Double Difference Combination rule, but they adopt different procedures to estimate the correlation between displacement responses of nonlinear hysteretic systems. The seismic excitation was modeled as a nonstationary random process, and adjacent structures were modeled as 5%-damped bilinear hysteretic SDOF systems having a 5% post-yielding stiffness ratio. Results obtained through Monte Carlo simulations indicate that none of the criteria evaluated in this study is completely satisfactory in the sense that none of them can consistently provide "exact" or "somewhat conservative" results.