Hybrid element-based virtual distortion method for finite element model updating of bridges with wide-box girders

A hybrid element-based virtual distortion method (VDM) is proposed to reduce the computational burden of finite element model (FEM) updating for bridges with wide-box girders. First, for the finite element modeling of wide bridges, a beam-shell hybrid element is proposed as an effective trade-off between the inadequate accuracy of beam-like elements and the low efficiency of solid or shell elements. Based on this, VDM is extended from a beam-like element to the proposed hybrid element to establish a metamodel for the FEM updating for wide bridges. Second, this paper describes in detail some key issues of this new type of VDM, such as generating the transfer and influence matrices, extracting the main virtual distortions and selecting the master degrees of freedom (DOFs) of the hybrid element. Finally, using the measured static deformation from a load test, the effectiveness of the proposed method is demonstrated by updating the FEM of an actual bridge.