Seismic performance and design of precast shear wall with headed bar overlap connections

A new type of precast steel reinforced concrete shear wall is proposed to serve as a lateral resistant member for residential structures. The vertical steel bars in precast shear wall within the horizontal joints are connected using confined headed bar connection (short in CHBC) while the profiled steels are bolted connection. Experimental investigations on the seismic behaviors of CHBC connected precast shear walls under combined axial and cyclic lateral loads have been conducted, with four specimens designed and tested, including three precast shear wall specimens and one cast-in-situ specimen. Through the hysteretic load-displacement curves and crack development patterns from tests, failure modes, bearing capacity, ductility, stiffness degradation, and energy dissipation properties of these specimens have been compared and investigated. Test results indicate that the CHBC connected precast specimen exhibits seismic performance as good as that of the cast-in-situ specimen, validating the effectiveness of the proposed horizontal joints. The precast specimen with ductility ratio of 5.89 exhibits 7.4% higher load bearing capacity than that of cast-in-situ specimen with ductility ratio of 5.70. All the specimens show the strength degradation ratio greater than 0.9 before peak load, demonstrating the stable load-bearing performance. Configuration details of the horizontal joints are suggested. Additionally, a simplified lateral resistance calculation model considering stirrup-confined concrete stress-strain relations is developed for CHBC connected precast shear walls under combined axial and horizontal loads. The average ratio between the predictions by the proposed model and test data is equal to 0.953. Besides, the simplified skeleton curve model is proposed, and the hysteresis rules are introduced which can demonstrate the hysteresis curves of the CHBC connected precast shear walls.