Seismic performance of precast reinforced concrete shear wall structure connected with vertical indirect-lapping joints

The current vertical joints of precast reinforced concrete shear wall structures (PRCSWS) usually have long protruding vertical connection bars, precise positioning of vertical connection bars and high time cost due to grouting, hence reducing construction efficiency and quality. This paper proposes a new indirect-lapping joint for the vertical connection of PRCSWS, which could potentially address the difficulties of wall panel transportation and installation. To investigate the seismic performance of the PRCSWS vertically connected with the proposed joint, one cast-in-situ specimen and three precast specimens with different joint designs were fabricated and tested under a pseudo-static setup. The failure mode, hysteretic responses, ductility, stiffness degradation, energy dissipation, and crack opening of the wall-foundation joint were compared for the seismic performance evaluation. The impacts of joint designs on the seismic performance of the specimens were further discussed, focusing on the confinement reinforcements and connection cage distribution. Compared to the cast-in-situ specimen, the research showed that the precast specimens had the same failure modes and similar ultimate capacities of around 600.0 kN. The precast specimen with smaller indirect lapping spacing had similar plastic deformability and energy dissipation ability, shown by the 27% difference in displacement ductility coefficient and similar energy dissipation accumulation, respectively. Although the precast specimens exhibited a lower initial stiffness than the cast-in-situ specimen by 17%, all the specimens tended to have similar stiffness degradation, reflected by the nearly overlapped equivalent stiffness curves. With the same connection cage design, the additional spiral confinement reinforcements for vertical joints could improve plastic deformability shown by the improvement of displacement ductility coefficient by up to 11%, and the crack opening of the wall-foundation joint could be reduced by up to 30%. Increasing the indirect lapping spacing weakened the plastic deformability and energy dissipation ability, shown by the decline of displacement ductility coefficient and energy dissipation accumulation by up to 43% and by 14% respectively, and the crack opening of the wall-foundation joint increased by up to 67%. This research could potentially promote the application of the proposed vertical joint and address the construction difficulties of the current vertical joints of PRCSWS.