Seismic performance study of a novel modular concrete building with infill walls in composite shear walls

Modular integrated construction (MIC) is an innovative prefabricated building system that involves connecting precast concrete modular units with cast‐in‐place concrete. In this system, MIC composite shear walls and infill walls serve as the primary vertical components. However, due to the fundamental differences in the coordinated deformation mechanisms between infill walls and the main structure, as opposed to those in traditional cast‐in‐place structures, the influence of infill walls on MIC composite shear walls remains unclear. To address this issue, three composite shear wall specimens with varying structural configurations were designed for this study. Quasi‐static loading tests were conducted to analyze the complete mechanical response, failure mechanisms, hysteretic behavior, strength degradation, stiffness degradation, and energy dissipation capacity of the specimens. The test results indicated that all three specimens experienced flexure‐shear failure. Their hysteresis loops were well developed, stiffness gradually degraded, and energy dissipation capacities were favorable. The infill wall significantly influenced the failure mode of the MIC composite shear wall. Compared to the bare specimen DZ‐1, specimen DZ‐2 with infill walls exhibited a 40.8% enhancement in ultimate load‐bearing capacity and a 26% increase in cumulative energy dissipation capacity. However, this configuration also induced accelerated strength degradation and a reduction in structural ductility. By incorporating a flexible isolation panel connection, specimen DZ‐3 demonstrated a 7.7% reduction in ultimate load‐bearing capacity and a 9% decrease in cumulative energy dissipation compared to DZ‐2. Nonetheless, this design effectively enhanced structural ductility and mitigated stiffness degradation. Based on experimental findings, a refined finite element model of the wall was developed using ABAQUS software to further investigate the collaborative load‐bearing mechanisms between MIC composite shear walls and infill walls of varying dimensions and material types. Corresponding design recommendations were subsequently proposed. This study clarifies the coordination mechanism of infill walls and their previously underexplored seismic performance, thereby establishing a theoretical foundation for MIC composite shear walls. Based on these findings, corresponding design recommendations are proposed to advance the development of prefabricated modular construction.