Seismic Risk Assessment of Nonengineered Residential Buildings in Developing Countries

A previous study by the authors provides an overview of existing seismic risk assessment approaches and available seismic fragility information and highlights the lack of relevant information for nonengineered residential buildings. The current paper proposes a procedure for developing empirical seismic fragility curves for nonengineered residential buildings using the U.S. Geological Survey (USGS) seismic ground motion and shaking intensity maps presented in a geographic information system (GIS) format, to overcome the lack of ground motion recordings. The proposed procedure has been applied to a damage data set collected in Bantul Regency, Indonesia, in the aftermath of the May 2006 Yogyakarta earthquake. Fragility curves for nonengineered single-story unreinforced masonry (URM) residential buildings have been derived using the damage data set for the peak ground acceleration (PGA) and pseudospectral acceleration (PSA) as the ground motion intensity measures. The developed fragility curves indicate the high seismic vulnerability of nonengineered residential buildings. This study also demonstrates the potential of utilizing USGS seismic ground motion data to develop empirical fragility curves for nonengineered residential buildings in developing countries. In addition, a comparison of the results from other seismic risk assessment studies highlights the significant influence of the derivation method used on the fragility curve characteristics.