Seismic fragility assessment of reinforced concrete wall buildings in Colombia: Insights and implications for earthquake-resistant design

Abstract

Colombia is in a high seismicity area where the Nazca and South American plate converge. Past earthquakes in 1985 and 1999 caused considerable economic and human losses to the country. As part of a seismic risk mitigation strategy, the National Geological Service commissioned a nationwide seismic risk model in 2022, which required developing seismic fragility functions representative of the country building stock. This article presents the seismic fragility results for conventional and thin reinforced concrete (RC) wall buildings. Conventional RC walls are those fulfilling ACI 318 provisions, and thin RC wall buildings (TRCWBs) are those reinforced with a single layer of a welded wire mesh with limited ductility. Leveraging a database of 259 structural drawings and models, 91 building archetypes were created in OpenSeesPy using a modeling approach that approximates non-planar walls with the MVLEM-2D. These underwent nonlinear dynamic analyses with over 3000 hazard-consistent ground motions, recording inter-story drifts, floor accelerations, and element forces. The results were used to calculate seismic fragility functions that served as input for the application of the FEMA P-695 methodology. The findings of this study provide fragility parameters for buildings between 4 and 30 stories constructed in low, intermediate, and high seismic hazard in Colombia, which are suitable for development of seismic risk scenarios. In addition, results also suggest that the Colombian code provisions for TRCWB require adjustments.