Wind-uplift fragility analysis of roof sheathing for cultural heritage assets in the Philippines

Abstract

Recent catastrophic events in the Philippines (e.g., the 2013 Typhoon Haiyan) have highlighted that ageing cultural heritage (CH) assets are especially vulnerable to typhoon-induced extreme wind. Non-engineered CH roofs have been recognized as the most vulnerable component in the building envelope due to wind uplift, often resulting in large economic losses and disruption for those assets. Effective prioritization of high-vulnerable structures is a key to effective risk mitigation and resilience-increasing strategies.This paper introduces a simulation-based approach for non-engineered CH roof fragility analysis (i.e., to assess the likelihood of different levels of roof damage over a range of wind hazard intensities) and risk assessment. In the proposed approach, two common failure modes are considered, corresponding to (first) roof-fastener pullout and roof-panel pullover. The overall aim is to identify the highest-risk candidate assets and prioritize more detailed data collection campaigns and structural assessment procedures (e.g., properly accounting for load redistribution and fastener failure progression), and ultimately to plan further repair/strengthening measures.An illustrative application of the proposed procedure is presented with reference to eight priority CH assets in Bohol, the Philippines. The analysis results indicate that, especially for roof panels supported by wood-type purlins, pullout fragility/risk can be significantly high, while the pullover one is generally lower.