A set of computer programs coded in Fortran language and integrated with commercial FE software is developed to implement the functions of the dynamic stress analysis of a multiload suspension bridge. A stepwise explicit integration method is adopted to find numerical solutions to the equations of motion of the wind-vehicle-bridge system. The aerodynamic wind forces acting on the car body of a train or road vehicle are determined using a quasi-steady approach.
The spatial distributions of both the buffeting forces and the self-excited forces over the bridge deck surface are considered in the dynamic stress analysis. All of the damping forces and nonlinear restoring forces of the suspension units are treated as pseudo forces in the train and road vehicle subsystems. The connections between the bridge and trains and between the bridge and road vehicles are considered. The mode superposition method is adopted to make the dynamic stress analysis manageable. In the framework, a complex finite element (FE) model of a suspension bridge is used for the stress analysis of the local bridge components, and the railway and road vehicles are also modeled using the FE method. In this thesis, a comprehensive framework is proposed for this analysis. To undertake the fatigue analysis of multiload suspension bridges, a dynamic stress analysis of the bridge under multiple types of loading must first be conducted. This thesis focuses on the fatigue and reliability analyses of multiload suspension bridges by making use of the information provided by WASHMS. The measured information provides an opportunity to carry out an accurate fatigue analysis of such bridges. To ensure the safety of such bridges and their users during their service life, several long-span bridges have been equipped with Wind and Structural Health Monitoring Systems (WASHMS), which measure the dynamic bridge responses and various loading types at the bridge site. Given the multiple types of loading concerned and the complexity of the loading combinations, the fatigue analysis of long-span suspension bridges under railway, highway, and wind loading is a great challenge. Many long-span suspension bridges throughout the world are subject to very complicated loading, especially those that are located in wind-prone regions and that carry both trains and road vehicles. Suspension bridges - Maintenance and repairīridges, Long-span - Maintenance and repairĭepartment of Civil and Structural Engineeringġ v. Hong Kong Polytechnic University - Dissertations Fatigue and reliability analyses of multiload suspension bridges with WASHMS
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