Outcomes from Field Measurements on the Magerholm Ferry Quay: System Identification, Finite Element Model Updating and Sensitivity 37 Fig. 5 Finite element model of Magerholm ferry dock in ABAQUS As described in section 2.1, the docking bridge is supported by the abutment and lifting towers in its free state. Consequently, constraints in the transverse and vertical directions are introduced at the abutment. Springs with a stiffness of 2000 kN/m (as specified by the provider) are modeled in the longitudinal direction at the positions of the conical fenders. The lifting towers, which support the bridge vertically, are represented by vertical springs. The initial stiffness of these springs was set at 10 000 kN/m, as the exact value is unknown and will be updated later. The mode shapes extracted from FE model are depicted in Fig. 6. Model Updating Methodology In this study, Mottershead’s sensitivity method [14] is applied to update the finite element model. This process is similar to an optimization problem, where the goal is to minimize the error between the FE model’s output and the field measurement results, thereby improving the approximation of the computer model to the actual state of the structure. The output used for comparison in this study is the natural frequency of the linkspan. To align the model output as closely as possible with the measured data, the input parameters θ of the FE model—such as material density, Young’s modulus, cross-sectional Fig. 6 First six modes of FE model
RkJQdWJsaXNoZXIy MTMzNzEzMQ==