Experimental Investigation of Structural Performance of Two-Story Structural ENTA Seismic Retrofitting System

Recent earthquakes in Korea have highlighted the necessity of seismic retrofitting. This study proposes an ENTA system as a strengthening method for wall-frame structures to ensure stability under large deformations while improving construction efficiency and cost effectiveness. Cyclic loading tests are conducted on a two-story RC frame retrofitted with the ENTA system to evaluate the performance of the system. The maximum load capacity, energy dissipation capacity, and initial stiffness of the retrofitted specimen are 1.62, 3.07, and 1.85 times higher than those of the nonretrofitted specimen. Furthermore, the energy-dissipation device yields prior to the main reinforcement, thus effectively sharing external forces and delaying damage to the primary structural members. These results confirm that the ENTA system effectively enhances the seismic performance of existing RC wall-frame structures, thereby achieving the intended design objectives.