Seismic performance of rocking‐delayed spine frame system with base initial gaps

Abstract

This study proposes a rocking‐delayed spine frame system that provides initial gaps at the side column bases of the spine frame. This system exhibits a trade‐off behavior between the nonuplifting spine system and uplifting‐allowed rocking frame system. The feasibility of the proposed system was verified on 16 specimens using cyclic loading tests. An evaluation of the force–deformation relationship of the proposed system was proposed and verified by comparing it to the test results. The seismic performance of the proposed system was investigated using nonlinear time‐history analysis. The analysis results clarified the initial gap's influence on seismic responses. A trade‐off between the maximum story drift ratio, peak floor acceleration, and maximum shear force of the spine frame was revealed.