Temporary Seismic Strengthening Methods for RC Columns under Post-Earthquake Conditions

Following major earthquakes, reinforced concrete (RC) columns often sustain severe damage that compromises structural stability and increases vulnerability to aftershocks. Rapid temporary strengthening is therefore essential to ensure safe access for emergency response operations and to prevent progressive collapse during the post-earthquake phase. This study investigates three modular steel-based temporary strengthening systems developed for the rapid stabilization of earthquake-damaged RC columns. The proposed systems include a steel jacket equipped with Added Damping and Stiffness (ADAS) dampers, a steel jacket incorporating corrugated steel sheets to enhance confinement, and a steel jacket combined with knee braces to improve lateral stability. An experimental program was conducted on scaled RC column specimens subjected to cyclic lateral loading under constant axial force. The columns were first tested to induce severe damage and were subsequently retrofitted using the proposed temporary systems and re-tested under identical loading conditions. The experimental results demonstrate that all three strengthening methods significantly improve strength recovery, reduce stiffness degradation, and enhance energy dissipation capacity compared to the unrepaired condition. Among the investigated systems, configurations incorporating energy dissipation mechanisms exhibited more stable hysteretic behavior and superior post-yield performance. From a practical perspective, the proposed modular systems can be rapidly installed using bolted connections and removed after permanent repairs are completed. Compared to conventional strengthening techniques, the proposed methods reduce installation time by approximately ۴۰% and overall costs by up to ۱۰%, highlighting their suitability for post-earthquake emergency applications. The findings confirm that modular temporary steel strengthening systems provide effective, rapid, and economical solutions for enhancing the immediate seismic safety of damaged RC columns.

کلیدواژه ها:

Temporary seismic retrofitting ، Reinforced concrete columns ، Steel jacketing ، Damaged RC column ، Post-earthquake Strengthening