Multi-criteria life-cycle assessment framework for resilient and sustainable seismic retrofit planning of RC buildings

Achieving both seismic resilience and sustainability has emerged as a critical objective in contemporary building design and seismic retrofit practice. However, these goals often require substantial upfront investment, leading to trade-offs between initial disaster-prevention costs and long-term benefits. To address this challenge, a life cycle-based multi criteria decision making (MCDM) framework is proposed to systematically evaluate retrofit strategies across four aspects: economic, environmental, social, and seismic resilience. A numerical integration-based approach is developed to calculate expected annual loss (EAL), providing a more stable evaluation of risk-reduction benefits before and after retrofit. The proposed approach reduces the variation in EAL estimation from 50% to 10% compared to baselines. Additionally, a Near-Fault (NF) ground motion scenario with magnitude 7.3 and velocity-pulse characteristics is simulated to assess the resilience index of selected retrofit strategies under user-sensitive seismic events. From an economic perspective, a Bayesian neural network (BNN) model is proposed to forecast initial retrofit costs while capturing uncertainty arising from data scarcity and market fluctuations. The initial retrofit investment is integrated with the benefit of the seismic risk reduction to derive the benefit–cost ratio (BCR), providing a key quantitative indicator for retrofit decision-making. The proposed framework is applied to a real-world retrofit case of a reinforced concrete (RC) building in Taipei, comparing the pros and cons of two strategies, i.e., RC jacketing and wing walls. Resulting recommendation has demonstrated that the proposed multi-criteria decision analysis shows operational feasibility and provides an adaptable decision-support tool for retrofit selection.