Seismic behavior of partially encased composite columns-steel plate shear wall structure with different semi-rigid joints

Seismic performance of partially encased concrete (PEC) column-steel plate shear wall (SPSW) structure is significantly affected by the characteristics of beam-column connections. Three component models of semi-rigid beam-column connections, including the bidirectional bolt extended end-plate connection, the flush end-plate connection, and the web double-angle steel connection, are designed according to Eurocode 3. Afterward, three 1/3-scale two-story singlespan PEC column-SPSW structures with the three types of semi-rigid connections are tested under quasi-static cyclic loading. The test results indicate that all three structures satisfy the design requirement of "strong frame-weak wall plate". The PEC-SPSW structure with the bidirectional bolt extended end-plate connections exhibits a higher bearing capacity and stiffness than the other two structures. Compared with the web double-angle connection, the adoption of bidirec-tional bolt extended end-plate connection increases the yield bearing capacity by 14.32% and the initial stiffness by 16.16%, but ductility decreases by 17.65%. The energy dissipation of each story of the structure with flush end-plate connections is relatively balanced. The energy dissipated by the second-story of SPSW is less than that of its first-story due to the higher rotational stiffness of the bidirectional bolt extended end-plate connections. The PEC-SPSW structures fracture at the column foot. The reliability of the initial rotational stiffness component models is verified by comparing the finite element (FE) and test results.