Assessing potential damage and energy dissipation in low-rise high-strength concrete frames with strong infill walls using applied element method

Structures sustain severe structural and nonstructural damage during seismic events like earthquakes. Strong infill walls increase the stiffness and load-bearing capacity of normal-strength concrete (NSC) frames. Still, their usage in tall structures needs larger lower-storey columns, which reduces livable area. Using smaller size columns in high-strength concrete (HSC) constructions provides an option; however, when combined with masonry infill, they become stiffer and more prone to catastrophic failure. On the other hand, detecting damage patterns in reinforced concrete framed structures is constrained by the limits of current computational approaches, viz., Finite Element Method (FEM), Discrete Element Method (DEM) and Rigid Body Spring Mechanism (RBSM). To address these issues, the current study applies the Applied Element Method (AEM), a potent numerical tool for reliable nonlinear analysis to track failure in all stages of loading. The study aims to evaluate cyclic load-induced damage in HSC frames with and without robust infill walls designed using Force-Based Design (FBD), particularly emphasising probable failures using principal strain analysis and energy dissipation. The plastic hinge formation comparison between HSC and NSC for multi-storey bare frame, soft-storey and fully infilled frames marked some important outcomes. The studied specimens followed a strong column–strong beam mechanism with strong infill. For soft-storey or Open Ground Storey (OGS) frames, it is observed that HSC-OGS frames have reduced failure points and inelastic response points compared with stabilised NSC-OGS frames. Additionally, larger columns are necessary for stabilised NSC-OGS frames but not for HSC-OGS frames on the ground floor, underscoring aesthetic considerations and saving space. However, due to strong infill interference, multi-storey infilled frames experience brittle shear failure at the ground floor beam-column connection. Caution is suggested when using HSC frames and strong infill to avoid potential brittleness and premature column failure. Revised design practices, such as Capacity Spectrum Design (CSD) and appropriate confinement techniques, must be incorporated to avoid these uncertainties in HSC frames.