Some experiences on reliability based aeroelastic analysis and optimization of long span bridges

Flutter instability in suspension bridges is a critical design constraint. It has been demonstrated over the years that wind tunnel tests produce the more reliable results although there is uncertainty in their values. Thus a probabilistic analysis approach is more appropriate when dealing with this kind of structures. In this research the probability of failure against flutter is obtained considering the wind velocity at the bridge location as well as the points that define the flutter derivatives as random variables. A reliability-based design optimization (RBDO) is also formulated to obtain the minimum deck and cable weight that guaranties a target safety level against flutter. Three RBDO methods are implemented in this research (Reliability Index Approach, Performance Measure Approach and Sequential Optimization and Reliability Assessment) and they are applied to the case of the Messina Bridge Project.