Risk-based life-cycle cost–benefit analysis for critical infrastructure: piled bridge abutments under earthquake loading

Abstract

Piled bridge abutments, which are essential components of transport infrastructure, are frequently overlooked in life-cycle performance design due to their perception as sources of uncertainty rather than as structural elements contributing to seismic resistance. This design oversight, coupled with limited research on seismic risks related to soil liquefaction during service life, has contributed to significant structural damage and traffic disruptions. This paper proposes a comprehensive framework for assessing the life-cycle seismic risk of critical infrastructure on liquefiable ground. A cost–benefit criterion is incorporated into the seismic risk analysis to evaluate return on investment (ROI). The life-cycle cost–benefit (LCC-B) model serves as an effective tool for evaluating both seismic life-cycle risk and the associated cost–benefit trade-offs. A case study focusing on the seismic risk analysis of a piled bridge abutment is included, examining the effectiveness of various ground improvement techniques, such as stone columns, deep-cement-mixing (DCM) columns, and DCM columns with non-uniform length, for mitigating soil liquefaction and associated ground deformations. The results demonstrate that DCM columns with non-uniform length design constitute the optimal solution for liquefiable ground, effectively reducing seismic risk and yielding a ROI of approximately 50%. The proposed framework and its outcomes offer practical guidance for strategic investments, enhancing the efficiency of transportation geotechnical asset management.