Seismic Fragility Analysis of Poorly Built Timber Buildings in Yangon Slum Areas

Abstract

In Yangon and the suburbs of Myanmar, timber-framed buildings are the popular choice of construction for residential purposes. Nearly 8% of the total population in Yangon live in the slums and slum-like areas where the dwellings are predominantly made of non-durable materials. Wood, jungle wood, and bamboo are used as the framework and corrugated galvanized iron sheets as walling and sheathing material. The seismic-resistance capacity of timber buildings in slum areas has never been approved based on experimental evidence. Therefore, this study aims to conduct a seismic fragility analysis for poorly built timber buildings by providing a suitable method through numerical and experimental approaches. Pull-over loading tests were conducted on selected buildings to assess their loading-displacement capacity. Further, numerical modeling was done using the Wallstat simulation tool, which is based on the discrete element method. The pushover curve was validated with the curve from the pull-over load test. Once the numerical model was confirmed, dynamic analysis was conducted for different peak ground acceleration (PGA) (g) values until the complete numerical collapse of the building. Three building configurations with three ranges of variable material properties were considered in this study. A primary damage state started at the low PGA value of 0.05 g, and it can be confirmed that the timber buildings that were studied, are vulnerable to earthquakes. The results based on qualitative analysis were accumulated to obtain the damage state matrix, which was then used to obtain the fragility curves.