Probabilistic Basis for Bridge Design Codes

There is a growing interest in the development of rational design criteria for bridges. The fundamental problem is evalution of the loads and load carrying capacity. However, load and resistance parameters (load components, material properties, dimensions) are random variables. Therefore, the reliability is a convenient measure of structural performance. Traditional approach was based on design of structural members rather than systems. In the paper, bridge load, resistance models, limit states and calibration procedure are reviewed. Most important research needs for the development of the bridge design code are also formulated.