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The precast shear wall behavior in the serviceability and ultimate limit states depends on the shear and shear-flexural behavior of the joints between the precast components or between the precast component and footing. This study presents a series of tests on the shear strength of joints, which were applied to the interface of precast shear walls. The tested parameters included the joint types, the numbers of shear keys, the existence of high strength steel bars inserted at the joints, and the levels of confining stress. The shear capacity, stiffness, and shear transfer mechanisms of these joints were investigated. It could be concluded that the epoxied and high strength reinforcing joints had consistently higher shear strength than that of dry and plain joints. For the specimens with an inclined angle at the end of the keys of less than 60 degrees, the width of the dry joint opening may be excessively large, resulting in large shear slip and the key not shearing-off under confining stress of less than 1.0 MPa. The tested results were compared with AASHTO and other design criteria. Several formulas regarding the joint shear capacities were also proposed according to the specifications and the tested results.

An experimental study of the seismic performance of composite frames consisting of reinforced concrete (RC) columns and steel beams (S) is presented in this paper. Three frame specimens-one bare composite RCS frame without slab and two composite RCS frames with slab-were tested under cyclic loading. The test results indicate that two frame specimens with small-scale steel beams exhibited better ductile behavior and dissipated energy, and the strength and stiffness degradation of the postelastic stage was not obvious. The results indicate that using a slab in the frame is not a good way to improve structural bearing capacity when the linear stiffness of steel beams is large. A plastic limit analysis method is proposed to calculate the lateral ultimate bearing capacity of an RCS frame under seismic action. The calculated results agree well with the test. Three RCS frame specimens were simulated using ABAQUS finite element analysis software. A comparison of the results of the numerical study with the experimental results demonstrates that the finite element model can accurately predict the structural behavior.

The behavior of precast concrete structures at the limit states of ultimate bearing capacity depends on the shear and shear-flexural behavior of the joints between precast components, such as shear wall and beam-column joints, or between the precast component and footing. This study presented a series of tests on the shear-flexural behavior of precast concrete joints applied in precast structures with high strength reinforcement. The tested parameters of the specimens included the joint type, shear-span ratio, longitudinal reinforcement ratio, reinforcement type, and prestress. The tested results indicated that, for the precast joint specimens controlled by shear failure, the prestress by the high strength reinforcement can significantly improve the crack behavior, shear bearing capacity and stiffness of the precast structure. So it can emulate the monolithic cast-in-place specimen. For the precast joint specimens dominated by bending failure, the local deformation was mainly concentrated on the precast joint region, which affected the distribution of the plastic hinge region. To reduce the adverse effects by the precast joints, a grouting material with better performance should be used to improve the bond behavior of the reinforcement.

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