Recycled concrete aggregates (RCAs) generated from construction and demolition activities have been recognized as a feasible alternative to natural aggregates (NAs). Naturally, the columns fabricated with reinforced recycled concrete (RRC) have been proposed and investigated to promote the structural use of recycled aggregate concrete (RAC). There is still, however, very limited modeling research available to reproduce, accurately and efficiently, the seismic response of RRC columns under lateral cyclic loading; proper evaluations are also lacking on addressing the columns’ seismic behaviors. To fill some of those research gaps, a fiber-based numerical model is developed in this study and then validated with the experimental results published in the literature. Subsequently, the numerical model justified is applied to carry out a comprehensive parametric study to examine the effects of a range of variables on the hysteretic characteristics of RRC columns. Furthermore, a grey relational analysis is conducted to establish quantifiable evidence of key variable sensitivities. The evaluation results imply that the use of the additional water method (AWM) for manufacturing RAC is likely to reduce the lateral load-carrying capacity of the RRC columns (up to 10%), whereas the opposite would occur if a conventional mixing procedure is adopted. Moreover, compared with other factors such as steel area ratio, the content of RCA replacement has a less remarkable effect on the seismic performance of the RRC columns. In general, the RRC columns possess acceptable seismic-resistant properties, and they can be used in earthquake-prone regions with confidence.

The flat slab-flanged wall (FSFW) coupled system has gained popularity in recent years; however, its seismic performance remains an issue, as beams and columns in it are commonly eliminated. To tackle this problem, embedding concrete-filled steel tubes (CFSTs) in wall piers has been proposed to strengthen the system; the viability of this approach has been verified at the member level. Along this line, this study embarks on a shaking table testing of a 1/8-scale five-story FSFW structure equipped with CFSTs in walls, with an aim to understand the overall seismic behavior of such an enhanced system. As with the practice in many countries, the plan layout of the test structure consisted of four rows of wall piers, thus presenting a ‘fish-bone’ floor configuration that relied only upon the walls to resist gravity and lateral loads. The structure was subjected to a suite of input ground motions along with white-noise excitations. By so doing, its damage progression, pattern and dynamic characteristics were clearly identified. Furthermore, a non-linear time history analysis was conducted using PERFORM-3D, and the goodness-of-fit of the computed responses to the experimental records was examined. Findings indicated that the application of CFSTs was instrumental in resisting the simulated earthquake loads acting on the FSFW system, hence the global response limits required by codes of practice were met, even in the case of extremely strong earthquakes. Nevertheless, the junction between the shear walls and floor slabs was found to be the weakest links in the whole system. Designers are thus cautioned to implement proper detailing in those regions to prevent local distress, though it did not appear to acutely impair the system’s collapse-resisting capacity.

Concrete-filled steel tubes (CFSTs) embedded in structural walls can improve the lateral-force resistance of slab–wall structures, but also impede the passage and anchorage of steel bars in slabs around the tubes. Therefore, the objective of this research is to propose the design of anchorage detailing to solve this problem, and analyze the bearing capacity and seismic performance of the joint using this design. Two types of no-through-tube anchorage detailing were put forward for steel bars in slabs that intersect with CFST-strengthened structural walls: (1) an anchoring ring (AR) detailing; (2) a direct anchoring (DA) detailing. Four slab–wall concrete specimens using these two detailing types were tested cyclically. It was found that the connection specimens with the AR detailing had better ductility and energy dissipation capacity compared to those with the DA detailing. Nevertheless, the connection specimens with the DA detailing had more direct force-transferring capacities, meaning that they were better at transferring the force received by the slabs to the shear walls. Overall, both types of detailing can be adopted in practice to significantly improve the seismic performance of slab–wall connections, and the choice of which to use would depend on the specific requirements of a project.