Finite Earthquake-Response of Inelastic Structure

A numerical procedure based on an absolute minimum principle has been developed for investigating the dynamic response of an inelastic structure at finite deformation. The inelastic response of a wide flange steel column, which is built in at the base and attached to a heavy mass at the top, to combined vertical and horizontal earthquake-type excitations, has been investigated. It has been shown that when the weight of the tip mass is much less than the Euler buckling load of the column, the dynamic response of the structure subjected to combined vertical and horizontal excitation does not deviate much from that caused by the horizontal excitation alone. However, when the tip mass is comparatively large, the vertical inertia force of the tip mass caused by the vertical excitation may influence the resultant motion of the structure under a combination of vertical and horizontal excitations, and consequently, the mode and time of collapse of the structure.