A model for partially dependent component damage fragilities in seismic risk analysis

This article proposes a model to quantify dependencies in component damage in the Federal Emergency Management Agency (FEMA) P-58 seismic performance assessment methodology and to simulate damage realizations with the desired dependencies. The model is compatible with the prior FEMA P-58 procedure and can quantify more realistic dependencies in component damage with only minor changes to the calculation algorithm and model parameters. This article introduces the proposed model and compares it with the prior procedure. Example calculations are then used to illustrate the quantitative impacts of component damage dependencies on building-level performance metrics. The model is relatively simple to conceptualize and parameterize, so that the degree of dependency can be easily estimated and documented. Given the improved conceptual framing of the problem, and the significant changes it sometimes produces in building-level performance predictions, this model represents an improvement to the general FEMA P-58 seismic performance assessment methodology.