Effect of rebar corrosion and soil settlements on seismic capacity of RC framed buildings

The seismic performance of existing buildings can be significantly affected by damage accumulation over time. This study focuses on a reinforced concrete (RC) building archetype representative of buildings designed for gravity loads only in the 1950s, subjected to both rebar corrosion and differential soil settlements. The building structure consists of unidirectional frames and one-way joist slabs according to design codes in force at the time of construction and associated engineering practice. A fiber-based modeling approach is used to capture the nonlinear behavior of materials and to simulate progressive effects of deterioration and deformations, or even damage, due to soil settlements under earthquake loading. Corrosion-related degradation of reinforcing steel is simulated through increasing levels of loss of material properties in the bare RC frame model. Results show that even moderate levels of corrosion or settlements can critically impact seismic performance when combined with each other, highlighting the importance of accounting for multiple degradation sources in the seismic assessment of existing RC buildings. Analysis results support multi-hazard assessment of existing RC buildings under material degradation, soil settlements and seismic actions.