Abstract
A rule to predict translational and torsional seismic responses of highly damped structure is proposed. The structure is non-proportionally damped, because flexible and weak frames are provided with large dampers mitigating torsion. Steady-state theory is adopted to reduce the structure to a single-degree-of-freedom system. Peak values of the two responses of the system are obtained as a product of Ritz Vector and the peak generalized displacement estimated from linear response spectrum. Ritz Vector consists of complex values to account for phase difference. The rule considers both linear and non-linear systems based on equivalent linearization technique. Accuracy of the method is demonstrated via numerous time history simulations of single-story models developing both translational and torsional motions.
