Modal Pushover Analysis Procedures Using Adaptive Load Distribution

The principal objective of this thesis is to extend the Modal Pushover Analysis (MPA) procedure to Displacement-Based Adaptive MPA procedure. A modal pushover analysis (MPA) procedure is an extension of pushover analysis procedure to take into account the contribution of the higher mode effects to the total seismic demands using invariant load distribution for each mode. In this study, to consider the effect of progressive structural yielding on the lateral load distributions in relation to the mode shapes, MPA procedure is modified by using variant (adaptive) load distributions for the fundamental mode and invariant (non-adaptive) force distributions for the higher modes. Comparative evaluation between the adaptive MPA (A-MPA) and MPA procedures in estimating seismic demands for a 9-story SAC steel building subjected to four different ground motions is explored relative to a rigorous nonlinear RHA. It is concluded that the adaptive MPA procedure is superior to MPA procedure in predicting the seismic demands of structure, especially under strong ground motion intensity.