Condition Assessment of Shear Connectors in Slab-Girder Bridges via Vibration Measurements

Abstract

The paper presents a field study on condition assessment of the shear connectors in a full slab-girder bridge via vibration measurements. Firstly, a model updating technique is employed to assess the condition of the whole structure including boundary conditions, bearings, girders, slab and shear connectors from the accelerations on the slab measured in vibration testing. Then, a new damage index based on the difference of frequency response functions on the slab and the corresponding points on the girder is developed to evaluate the condition of shear connectors. The advantage of the new method lies in the fact that it does not need any reference data (undamaged data) for the structure. Compared with the results obtained using the model updating technique, the method is more reliable and accurate in assessing the condition of the shear connectors between the slab and girders. The effect of measurement noise on the damage identification results and the damage quantification are also studied through numerical simulation.

Evaluation of Bridge Load Carrying Capacity Using Updated Finite Element Model and Nonlinear Analysis

“…Because of the increasing traffic loads, the revised code requirements, and possible damage caused by floods, it is important to evaluate the bridge conditions and its current load carrying capacity accurately. For these purposes, field vibration tests were carried out in late September 2004 and again in early October 2005 (Xia et al 2007(Xia et al , 2008. The field test data will be used in this study to update the finite element model and assess the performance of the bridge.…”

“…The locations of the lumped shear connectors are shown in Figure 10. The accuracy and efficiency of this simplification was verified by Xia et al (2008). The three dimensional two-node truss elements, T3D2, are used to model stirrups.…”

“…The field tests were carried out in (Xia et al 2008. Hammer impact was used as the excitation source.…”

Inverse substructure method for model updating of structures

“…This differs from the substructuring model updating method previously This is the Pre-Published Version. 2 proposed by the authors, in which the model updating is still conducted in the global level and the numerical global modal data are assembled from those of substructures. That can be referred to as the forward substructuring model updating method.…”

“…The FE model of a large-scale structure usually consists of a large number of degrees-of-freedom (DOFs) and many uncertain parameters, which make the conventional model updating method expensive in terms of computation time and computer memory. Xia et al [2] carried out a model updating exercise for the Balla Balla Bridge in Western Australia; the bridge was modeled with 907 elements, 949 nodes, and 5,400 DOFs. Optimization convergence took 155 iterations and took about 420 hours.…”