Static and dynamic evaluation of a butterfly-shaped concrete-filled steel tube arch bridge through numerical analysis and field tests

Abstract

The butterfly-shaped concrete-filled steel tube (CFST) arch bridge is an irregular bridge with unique esthetics. In this paper, this new shape of CFST arch bridge is introduced, and a refined three-dimensional finite element model (FEM) is established to evaluate static and dynamic behavior of the bridge. In order to reduce model errors, the FEM is calibrated according to numerical analysis and field tests. Static calculation results show that the butterfly-shaped bridge has good structural performance. The bending moment and axial force of the arch ribs increase when the camber angle of suspender changing from 15° to 50°. Dynamic test is carried out by ambient vibration testing under traffic and wind-induced excitations. The modal parameters of the bridge were calculated by the stochastic subspace identification method in the time domain. In terms of natural frequencies and mode shapes, the FEM analysis was validated by experimental modal analysis. The updated model thus obtained can be treated as a baseline finite element model, which is suitable for long term monitoring and safety evaluation of the structure in different severe circumstances such as earthquakes and wind loading in future.