COMPONENT-BASED SEVERE WIND VULNERABILITY ANALYSIS OF WOODEN BUILDINGS IN THE PHILIPPINES

Abstract

The Northwestern Pacific Ocean Basin is home to the strongest tropical cyclones in the world, called typhoons. The Philippines is situated as the gateway for the typhoons developing in the Northwestern Pacific Basin. As a result, the country is being exposed to the risk brought by significantly strong typhoons that occur more than once annually. Lightweight buildings, particularly wooden buildings, and their structural components are the most vulnerable to severe winds. This study aims to perform vulnerability analysis on wooden buildings, by developing vulnerability curves that relate the magnitude of severe winds to the variation of damages and by establishing the probabilities of identified damage states of the buildings at certain wind speeds - which are called fragility curves. This study employs an improved framework from a heuristic-empirical-computational methodology previously used in determining GMMA-RAP vulnerability curves. This enhanced framework uses a component-based Monte Carlo vulnerability analysis to determine the improved vulnerability curve to account for the statistical variations of documented building damage from severe winds. A maximum, average, and minimum vulnerability curve were developed by fitting a cumulative lognormal distribution function wherein the mean parameters are 250.92, 425.89, 148.80, and the variance parameters are 0.579, 0.257, 0.433, respectively—the functions used an offset of 72 kph for all the developed curves. The developed curves were then compared to empirical field survey data, wherein 71.43% of the empirical data was within the developed envelope.