Analytical Investigation for Improved Connection Models of Diagonal Braced Frames

In general, the brace is connected to the beam and column through a gusset plate connection, which in fact has a stiffness between pin joint and rigid joint. However, in practice, due to the complexity of detailed joint modeling, it is considered as a pin joint, which leads to inappropriate analysis results. In this study, an analysis model that can be reasonably applied in practice was proposed. Nonlinear static analysis of two-dimensional (2-D) and three-dimensional (3-D) diagonal braced frames was performed through SAP2000, and the performance of the proposed model were compared with the pinned model. In addition, the effect of the gusset plate connection on the seismic performance was analyzed by evaluating the performance levels of the two analysis model. As a result, the pinned model conservatively evaluated the resistance and performance level of the braced frame. This can occur reliability problems on the analytical model and lead to uneconomical designs in practice. Therefore, it is important to use an analytical model that considers the gusset plate connection for accurate and economical seismic performance evaluation.