Seismic performance of multi-story glulam post-and-beam structures reinforced with knee-braces

Abstract

The glulam post-and-beam structure reinforced by knee-braces is a promising option for multi-story buildings with a compromise between architectonical space and lateral resistance. In this study, four glulam knee-braced frame structures with different heights (i.e., 3-story, 5-story, 6-story, and 9-story structures) were designed as the prototype buildings. Then, nonlinear numerical models were carefully established, and the crucial component behavior in the structure was calibrated by experimental results. Fifty mainshock earthquake records and mainshock-aftershock earthquake records were selected as the excitations for the nonlinear dynamic numerical simulation. The maximum inter-story drift (MaxISDR) and the residual inter-story drift (ResISDR) were obtained. The seismic performance of these prototype buildings was subsequently evaluated based on probabilistic seismic demand analysis (PSDA). The analytical results show that the glulam knee-braced frame structures have a desirable seismic performance due to the ductility of the connections and the knee braces. However, for the glulam knee-braced frame structures that exceed six stories, it is recommended to use additional reinforcing systems (i.e., diagonal braces or infill light-frame wood shear walls) to avoid premature damage of the knee braces and to increase the lateral stiffness of the structure. The presented seismic performance evaluation in this paper can be used as a reference for the development of seismic design guidelines for glulam knee-braced frame structures.