Risk assessment framework for seismic retrofitting of RC columns through jacketing: A bowtie approach

Abstract

Technical standards for seismic retrofitting of reinforced concrete (RC) columns through jacketing address capacity calculations, yet the planning phase lacks structured methodologies for systematic risk assessment. This paper presents a Bowtie-based framework integrating threat identification, barrier specification, and cost-benefit analysis for column jacketing interventions. Developed through Design Science Research combining literature synthesis and consultation with eight experienced professionals, the framework identifies six threats and five consequence categories, specifying eleven barriers (six preventive, five mitigating) with explicit baseline effectiveness values, aligned with ACI 318, Eurocode 8, ISO 31000, and OSHA standards. Sensitivity analysis through one-at-a-time variation and Monte Carlo simulation (N = 10,000) confirms robustness, with ±20% barrier effectiveness variation producing consistent ordinal-level risk changes across all threats. Cost-benefit analysis shows preventive barriers require 13–25% of intervention costs, while failure consequences—comprising demolition, reconstruction, litigation, and schedule penalties—may represent substantial multiples of the original budget. An illustrative case study demonstrates systematic risk-level reduction across all threats with 13.5% barrier investment. The framework advances risk management from reactive troubleshooting to proactive, risk-informed planning in structural rehabilitation.