Determining the structural properties of concrete bridges through the combination of static and dynamic load testing

Examining structural safety requires assumptions regarding several properties of the bridge structure, such as the material properties, boundary conditions, and self-weight. The traditional approach is to assume conservative values for each bridge property, following the conventional new-design philosophy. Nonetheless, this approach leads to conservative evaluations of bridge capacity and may lead to the inaccurate conclusion that the structure is deficient. Over-conservative in structural safety assessments has large negative environmental and economic impacts on global infrastructure management. Another approach is to conduct multiple tests and monitoring activities on the structural system to determine the values of these bridge properties more accurately. This paper presents a methodology to determine several parameters, including the structural stiffness, the boundary conditions, and the self-weight of concrete bridges based on data from static and dynamic load testing. The methodology is used on a prestressed concrete bridge in Switzerland. This bridge from 1958 has a single span of 35 meters and has been significantly strengthened and widened in 2023. By accurately identifying the selfweight, this study shows the potential of bridge monitoring for a more sustainable and economic infrastructure management.