MULTI-MODAL MULTI-PATTERN PUSHOVER ANALYSIS FOR SEISMIC DESIGN OF SPATIAL FRAMES

A new approach is presented for determination of equivalent static seismic loads for evaluating maximum seismic responses of spatial frames. The responses are estimated by series of pushover analyses considering possible phase di erences in the dominant modes. The vibration modes of the initial elastic structure are used, and the damping due to plastic dissipation is modeled by equivalent linearization for inelastic systems. The accuracy of the proposed method is demonstrated in the numerical examples of an arch-type long-span truss and a 3story 3-dimensional building frame.