Experimental and numerical evaluation of RC wall-retrofitted two-story RC frames: Hysteretic behavior and optimal wall configuration for seismic performance

초록

This study investigates the seismic performance enhancement and optimization of reinforced concrete (RC) two-story frames retrofitted with an RC wall system through an integrated experimental, numerical, and performance-based evaluation approach. A quasi-static cyclic loading test was conducted on a single RC frame specimen retrofitted with an RC wall to examine hysteretic behavior, failure mechanisms, and energy dissipation characteristics. The experimental results indicate that the retrofit system improves lateral strength, stiffness, and ductility, while promoting a controlled deformation mechanism consistent with strong column-weak beam and wall-dominant behavior. A detailed finite element model was developed and validated against the experimental results of the retrofitted frame, showing good agreement in hysteresis responses, envelope curves, and damage patterns, with key seismic performance indicators predicted within a +/- 5% accuracy range. The validated numerical model was subsequently used to evaluate the seismic response of the corresponding as-built RC frame, enabling a comparative assessment of retrofit effectiveness. Performance-based seismic evaluation using the capacity spectrum method indicates that the retrofit intervention upgrades the structural performance from the Life Safety level to the Immediate Occupancy level according to FEMA 356 criteria. An energy-based damage assessment further confirms reduced damage accumulation in the retrofitted frame. In addition, a parametric investigation of wall height ratio (WHR) and wall thickness ratio (WTR) identifies optimal ranges of approximately 0.4-0.6 and 0.05-0.07, respectively, for achieving a balanced improvement in stiffness and energy dissipation.

키워드