Seismic vulnerability assessment of residential buildings in Sri Lanka

Abstract

Although Sri Lanka is generally considered to be in a low-seismicity region, historical records and recent hazard studies indicate that potentially damaging earthquakes may occur, while nonengineered masonry housing may remain vulnerable to such loading. This study assessed typical single-storey residential buildings using ETABS-based numerical modelling and qualitative reduced-scale prototype testing. Three representative models were analysed as masonry-only and with concrete columns, beams and lintels. Equivalent static and response spectrum analyses were used to evaluate base shear, roof drift and shell-stress concentrations, while theoretical time histories were used for shaking-table testing. The masonry-only model, Model 02(A), showed the highest drift and lowest stiffness, with critical stresses around openings, corners and wall junctions. Concrete elements reduced the X- and Y-direction roof drifts of the model by 90.1 percent and 84.8 percent, respectively. Rammed earth (RE) prototype testing also showed lower wall-top displacement after improvement. The findings demonstrate that building layout, wall connectivity and opening arrangement strongly influence seismic response and that appropriate concrete elements can improve the behavior of typical masonry houses.