Development of a Macroscopic Global Seismic Damage Model for Lattice Shell Structures

Abstract

A physics-based macroscopic global seismic damage model is developed for lattice shell structures excited by strong earthquakes. Global seismic damage is generated from so-called modal damage that is defined as the loss ratio of potential energy stored in structures before and after earthquakes, with the combination rule based on the assumption of in-series independencies among modal damages involved. The minimum number of lower modes required in the combination is determined by the suggested procedures using the maximum nodal displacement as a key response quantity. The issue of modal match arises from the modal shift phenomenon that commonly exists in aseismic lattice shells is solved by the linear modal assurance criteria (LMAC) approach. The case study indicates that the predictions result from the model exhibit a desirable correlation with the maximum nodal displacement time history response and a good tendency in damage evolution as more modes are involved. The global damage curves can comply with a typical six-segment positive S-type damage evolution curve. The model can be regarded as an extension to the final softening model proposed by DiPasquale and Cakmak.