Influence of Isolation Gap Size on the Collapse Performance of Seismically Base-Isolated Buildings

The pounding of retaining walls forms a potential risk of degrading the performance of seismically base-isolated buildings subjected to strong, especially near-fault, earthquake ground motions. Incremental dynamic analysis is employed to generate the so-called gap graph, in which two characteristic gap sizes of a base-isolated building are related with the isolation period of the building and the strengthof the superstructure. Thegapgraph canbe usedto evaluate the required gap size for a base-isolated building to have certain collapse performance. By means of gap graphs, the interdependent relations of gap size with other important factors that influence the seismic performance of the base-isolated building are examined. In particular, the results show that near-fault pulse-like ground motions are likely to impose much higher demand for the isolation gap than far-field ones.