Risk-based lifecycle benefit-cost analysis for tornado hazard mitigation for wood-frame residential buildings

The increasing frequency and intensity of tornadoes, exacerbated by climate change, underscore the urgent need for resilient and economically sustainable infrastructure.This research evaluates the benefit-to-cost tradeoffs of designing risk category II wood-frame residential buildings to withstand tornado loads which currently lack coverage under the recent update to the ASCE/SEI 7-22 standard.The current standard newly incorporated design requirements for Risk Category III and IV buildings in tornado-prone areas, yet residential structures, which account for two-thirds of tornado-induced structural damage and most related fatalities, remain excluded. This study integrates probabilistic tornado hazard models with building fragility functions to evaluate the performance of minimum-standard and tornado-resistant residential buildings for up to EF-2 tornado-resilient designs. The resulting damage estimates are incorporated into a life-cycle cost model to calculate the expected economic losses due to tornado hazards over a building's lifespan. A subsequent benefit-cost analysis compares these losses with the benefits of implementing tornado-resistant design features. A Monte Carlo Simulation (MCS) is employed to quantify uncertainties in life-cycle cost and benefit-to-cost ratio (BCR)estimations.By generating stochastic samples for initial construction costs, additional cost due to tornado-resistant construction, and building damage ratios.The MCS produces robust statistical distributions of economic outcomes over varying analysis periods.The analysis focuses on one-story single-family wood-frame residential buildings located in tornado-prone regions as specified in the ASCE/SEI 7-22 tornado maps.The study presents location-specific BCRs and net present costs due to tornado events over time for a one-story single-family home.The findings from this study provide valuable insights into the tradeoffs between upfront investments in resilience and long-term economic benefits.