Integrated Seismic and Energy Retrofit Strategies for RC Buildings with Masonry Infill Walls: A Resilience-Based Assessment.

Italy’s residential building stock includes a vast number of reinforced concrete (RC) structures designed without modern seismic and energy efficiency standards. These buildings invariably feature masonry infill walls, which play a critical role in seismic performance due to their vulnerability to brittle failure. Therefore, a realistic seismic resilience assessment must account for both structural and non-structural components. In light of emerging technologies and the increasing demand for sustainable retrofitting, integrated seismic and energy interventions have become increasingly relevant. These strategies can effectively build upon the tuned mass damper (TMD) concept, its advanced inerter-based configurations (TMDI), and base isolation (BI) systems. This study presents a detailed seismic resilience evaluation of a representative three-story RC residential building with masonry infill walls. Beams, columns, and infill panels are modelled using a lumped plasticity approach to capture nonlinear flexural and axial behavior under dynamic loading. Nonlinear time history analyses are performed using input motions consistent with the seismic hazard levels expected in Italy. The building is assessed in its original state and under various passive retrofit strategies, including TMD, TMDI and BI. These interventions are selected for their potential to reduce seismic demand and improve post-event functionality and are combined with energy efficiency measures to support a more holistic retrofit approach. A performance-based framework is defined to quantify seismic resilience through key indicators such as inter-story drift, peak floor acceleration, plastic rotation, and recovery time. The originality of this work lies in integrating realistic infill wall modeling in RC frame structures with a resilience-based assessment across multiple retrofit techniques. The findings support the development of holistic retrofit solutions that enhance both safety and sustainability in Italy’s vulnerable urban building stock.