Synergistic working performance of PEC hidden columns and RC composite short-limb shear walls

Considering the superior seismic performance of partially-encased composite steel and concrete (PEC) columns, aiming at the issues of poor ductility and out-of-plane stability found in traditional reinforced concrete (RC) short-limb shear walls. A novel approach has been proposed to achieve this goal involving PEC hidden columns and RC composite short-limb shear walls (PECSWs). This paper designed and executed quasistatic tests of two PECSWs and examined the failure mechanism of the specimens. To address the bond-slip failure problem between the PECSWs, the seismically damaged shear walls were restored by adding studs and subsequently underwent quasistatic testing after repair. Based on the seismic damage model of short-limb shear walls, model validation and parameter expansion analysis were carried out using finite element analysis (FEA). The test results indicate that the PECSWs experienced shear-bond failure under seismic action, while the repaired specimens experienced diagonal shear failure. The overall performance of the repaired specimens significantly improved. The parameter analysis indicates that the two measures of increasing the rebar diameter and reducing the rebar spacing were ineffective in improving the overall performance of PEC hidden columns and RC shear walls or reducing the effect of interfacial bond-slip. As the axial compression ratio, concrete strength, steel plate strength, and main steel component plate thickness increased, the lateral stiffness and bearing capacity of the shear wall improved, but the ductility decreased slightly. Based on the force transmission mechanism of the oblique belt-truss mechanism, a calculation formula for the shear bearing capacity of PECSWs is proposed. The theoretical calculations are in good agreement with the tests and FE results. •A new prefabricated PEC hidden columns and RC composite short-limb shear walls (PECSWs) structure was proposed.•The construction method of adding studs is adopted to repair the earthquake-damaged shear wall.•The seismic performance of the shear wall structure is studied through experimental analysis.•The calculation formula of the shear bearing capacity of the shear wall structure has been derived.•The finite element model is in good agreement with the test.