This paper has focused on the structural performance of recycled aggregate concrete (RAC) under both cyclic and monotonic loading. RAC specimens with different recycled coarse aggregate (RCA) replacement percentages of 0%, 25%, 50%, 75% and 100% were cast and tested. The compressive stress-strain relationship and the failure mode were investigated for each RCA replacement ratio. The effects of the RCA replacement percentage on the compressive mechanical properties of the RAC specimens including the strength, elastic modulus, peak strain, ultimate strain and Poisson's ratio were also studied. The RAC specimens have shown similar failure characteristics regardless of monotonic or cyclic loading. In addition, the compression skeleton curves of the RAC specimens under cyclic loading agree well with those under monotonic loading. Based on the experimental results, the characteristic points pertaining to the hysteresis loop were defined and their relations were established. Furthermore, the constitutive equations of the RAC as well as its simplified form were proposed and applied in numerical simulations of RAC columns and frames under cyclic loading. The proposed constitutive equations have shown promising accuracy in predicting the hysteresis performance of RAC on both component and structural levels.

This paper presents a numerical procedure to simulate the rocking response of self-centering walls under ground excitations. To this aim, the equations of motion that govern the dynamic response of self-centering walls are first formulated and then solved numerically, in which three different self-centering wall structural systems are considered, that is, (i) including the self-weight of the wall only, (ii) including posttensioned tendon, and (iii) including both posttensioned tendon and dampers. Following the development of the numerical procedure, parametric studies are then carried out to investigate the influence of a variety of factors on the dynamic response of the self-centering wall under seismic excitations. The investigation results show that within the cases studied in this paper the installation of posttensioned tendon is capable of significantly enhancing the self-centering ability of the self-centering wall. In addition, increasing either the initial force or the elastic stiffness of the posttensioned tendon can reduce the dynamic response of the self-centering wall in terms of the rotation angle and angular velocity, whereas the former approach is found to be more effective than the latter one. It is also revealed that the addition of the dampers is able to improve the energy dissipation capacity of the self-centering wall. Furthermore, for the cases studied in this paper the yield strength of the dampers appears to have a more significant effect on the dynamic response of the self-centering wall than the elastic stiffness of the dampers.

This paper presents a proposed uniaxial damaged plastic constitutive relation of recycled aggregate concrete (RAC) based on the experimental studies. A total of five groups of RAC specimens with different recycled coarse aggregate (RCA) replacement percentages of 0, 25%, 50%, 75%, and 100%, respectively, are tested under both monotonic loading and cyclic loading. The effect of the RCA replacement percentage is thoroughly investigated on a variety of mechanical properties, including the compressive strength, the peak strain, and the elastic modulus. Based on the test results, a uniaxial damage plastic constitutive relation of the RAC is proposed within the continuous thermodynamics framework. After validated by the experimental results, the proposed damaged plastic constitutive relation of the RAC is applied to perform nonlinear analysis of the RAC columns under cyclic loading, which provides close predictions of the hysteresis behavior of the RAC columns.

A novel reinforced concrete (RC) segmental coupling beam (SCB), which mainly comprises the energy dissipating (ED) segment and load bearing (LB) segment, is proposed in this paper. In order to examine its applicability in engineering practice, one scaled RC coupled wall specimen with the proposed SCBs was constructed and experimentally investigated under cyclic loading. The results show that both cracking and yielding occurred much earlier on the ED segments of the SCBs compared to the LB segments. In addition, a lot more cracks distributed densely on the ED segments were observed at the end of the test. It demonstrates that the ED segments play a main role in the energy dissipation, while the LB segments are always reliably capable of carrying the gravity load transferred from the floor beams. Finally, the finite element analysis model of the RC coupled wall is established and validated by comparing the analysis results with the experimental ones. Utilizing the proposed analysis model, parametric analyses are conducted to investigate the influence of a variety of design parameters, including the axial compressive ratio of the wall pier, concrete strength, and especially sectional height of the SCB, on seismic performance of the coupled wall. It shows that as the sectional height of the ED segment increases, the energy dissipating capacity of the coupled wall may improve while the ability of supporting the gravity load is lowered.