Total Risk Model and Loss Analysis of Probabilistic Damage Control Application in Seismic Design of Highway Bridges

Probabilistic Damage Control Application (PDCA) has been developed to apply the performance-based earthquake engineering (PBEE) to the seismic design of highway bridge structures. The main component of the PDCA is the total risk that enables designers to conduct a life-cycle cost analysis and to answer the owner’s cost-related questions such as how to optimize the design by balancing two primary decision-making parameters: performance and cost. This paper introduces an enhanced total risk model adopting the backbone formula used for calculating the annual rate of exceeding intensity measure (IM) level in Probabilistic Seismic Hazard Analysis (PSHA). The life-cycle cost analysis is a function of initial construction cost, repair costs, and economic loss. The inclusion of expected repair costs and economic consideration results in a comprehensive life-cycle cost analysis that makes the PDCA methodology unique. A detailed case study using a multispan bridge is presented as an example to show how to apply the PDCA framework into the bridge design practice with an emphasis on the life-cycle cost analysis that is computed using the total risks. Bridge column is the main seismic critical member in the bridge system that has nonlinear performance under seismic events. The total risk model and loss analysis of the PDCA addressed in this paper is based on the seismic performance of the bridge columns only. Other components such as abutment and in-span hinge seat widths that will have some contribution to the total risk may be considered in the future.