V-FAST: A story-based vulnerability and fragility assessment toolkit for advancing PBEE

This article introduces V-FAST, an open-source computational platform designed to support the implementation of performance-based earthquake engineering (PBEE). V-FAST enables the estimation of fragility functions for individual buildings and representative taxonomies and the calculation of vulnerability functions using a story-based methodology. This story-based loss estimation (SBLE) approach leverages structural response data and component-level damage models to compute expected losses at the component, story, and building levels. The platform integrates key components of the Pacific Earthquake Engineering Research (PEER)-PBEE framework into a streamlined workflow that enhances interpretability and facilitates its application across research, academic, and professional settings. V-FAST features a graphical interface that provides full visualization of inputs, intermediate computations, and final outputs, thereby improving usability and transparency. While initially developed to support national risk modeling efforts in Colombia, its structure and flexibility make it broadly applicable for detailed seismic risk assessments in diverse contexts.