Moment-rotation behavior of top-and seat-angle connections with double web angles

The objective of this study is to develop more accurate models to estimate the moment-rotation behavior of top-seat angle connections with double web angles (TSACW). As the characteristics of connections play a very important role in steel structural design, the effects of connections should be considered when an accurate analysis of semi-grid steel frame is desired. Experimental data of TSACW collected is used for evaluating different models, such as the initial stiffness and ultimate moment. Experimental data of top-seat angle connections without web angle collected is used to establish the effect of top and seat angle on the initial stiffness of TSACW. A more accurate equation for the initial stiffness is proposed, and good agreement between the proposed model and various test data is made. The type of collapse mechanism for TSACW is established from Kishi and Chen, Li, and Kong and Kim's analysis. A model of the ultimate moment capacity is proposed, and it agrees well with various test data. A more accurate model of the moment-rotation relation is also suggested.