Vibration Testing and Finite Element Modelling of a Steel-Concrete Composite Bridge

This paper presents the results from the dynamic behavior assessment of Olona West Bridge. This highway bridge is located in the province of Varese (Lombardy region, Italy) and crosses the Olona river. It consists of four spans: two central spans of 66m long and two lateral spans of 55m long. The bridge consists of a steel-concrete composite deck, which is supported by two abutments and three concrete piers. The research involved three main steps: (i) a review of the available technical documentation (ii) ambient vibration testing and modal identification, and (iii) finite element (FE) modelling, correlation and updating. The ambient vibration testing was conducted under operational excitation, mainly traffic and wind loads. Operational modal analysis (OMA) was applied to determine the experimental modal parameters, using frequency domain and time domain identification techniques. Furthermore, a FE model of the entire bridge was developed in ABAQUS software using beam and shell elements. Numerical results, in terms of natural frequencies and mode shapes, were compared to experimentally identified dynamic characteristics. The numerical model was manually updated achieving a good agreement with the experimental data. Future developments involve the installation of permanent sensors to assess the structural health of the bridge in real-time.