Cyclic Loading Test for Composite Walls with U-Shaped Steel Boundary Elements

A steel–concrete composite wall with boundary elements of steel U-section was developed for high structural performance and efficient use of materials. Cyclic lateral loading tests were performed on the proposed walls to investigate the flexural and shear performances. The test parameters included the failure mode of specimens, type of boundary reinforcement, sectional area of steel U-sections, horizontal web reinforcement ratio, and wall thickness. In the flexural yielding specimens, the flexural strengths of the proposed walls were equivalent to those of conventional reinforced concrete (RC) walls with boundary elements of vertical rebars, even though the yield strength of steel plates was 24% less than that of rebars. Further, the use of steel U-sections increased displacement ductility and energy dissipation, providing lateral confinement to the boundary concrete and restraining shear cracking and sliding. In the shear failure-mode specimens, the use of steel U-sections increased the diagonal tension-shear strength of walls. Thus, the shear strength of the composite walls was greater than that of conventional RC walls. The existing design method of JGJ 138 reasonably predicted the shear strength of the proposed composite walls, considering the contribution of boundary steel U-sections.