In-plane cyclic behavior of RC frame subassemblies with novel porous metamaterial infill walls: A numerical investigation

Infill walls play an important role in the in-plane seismic response of reinforced concrete (RC) frames. This study investigates the quasi-static cyclic response of a single-story, single-bay RC frame subassembly incorporating a porous metamaterial infill wall (PMIW) made of polypropylene fiber-reinforced ceramsite concrete. The frame modeling method and the material constitutive model were separately checked against published experimental results. Ten numerical models were analyzed in terms of stress distribution, damage evolution, hysteretic response, load-carrying capacity, ductility, energy dissipation, and stiffness degradation. The results show that the cellular topology transfers load through multiple ligaments and allows damage to develop progressively instead of forming a dominant diagonal damage path. Compared with the conventional infill-wall model D0-R0-L0, D200-R30-L20 increased the peak load by 3.8% and the cumulative energy dissipation by 42.4%. At fixed D and L , cumulative energy dissipation increased as R increased from 20 to 40 mm but decreased when R reached 50 mm. At fixed D and R , it decreased continuously as L increased from 10 to 40 mm. Among the three proportional-scale configurations, D200-R30-L20 showed the highest cumulative energy dissipation. Because D , R , and L changed simultaneously in this series, this result reflects their combined effect rather than the independent influence of D . Further experimental studies are needed to verify the response of the complete PMIW–RC frame system.