Finite beam element with 22 DOF for curved composite box girders considering torsion, distortion, and biaxial slip

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(2020) 20:101

ORIGINAL ARTICLE

Finite beam element with 22 DOF for curved composite box girders considering torsion, distortion, and biaxial slip Li Zhu1 · Jia‑Ji Wang2   · Ming‑Jie Li3 · Chao Chen1 · Guang‑Ming Wang1 Received: 9 March 2020 / Revised: 4 June 2020 / Accepted: 27 July 2020 © Wroclaw University of Science and Technology 2020

Abstract Experimental and numerical study on the mechanical performance of curved steel–concrete composite box girders is reported in this research. First, this research establishes a theoretical model for curved composite girders with 11° of freedoms (DOFs) for each node. The DOFs include the longitudinal displacement, transverse displacement, deflection, torsion angle, warping angle, and interface biaxial slip between steel and concrete. Based on the virtual work theorem, the equilibrium function, the stiffness matrix, the node displacement matrix and the external load matrix are proposed for the curved composite girders using the FE spatial discretization. Second, the authors conduct an experimental program on three large-scale curved composite girders with various interface shear connectors and central angles. The comparison between the developed finite beam element, the elaborate FE model and the test results indicates the developed finite beam element has an adequate level of accuracy in predicting the deflection, the torsion angle and the axial strain distribution of test specimens. Third, based on the developed finite beam element model, the effect of initial curvature, number of diaphragms, and the interface connector stiffness on the curved composite girder is examined. The simulation results showed that the initial curvature significantly contributes to the displacement and stress of composite girders. Applying more diaphragms can notably reduce the distortion angle and distortion displacement. The interface shear connector stiffness has a significant influence on the curved composite girder. With the increasing shear connector stiffness, the displacement and stress of curved composite girders decrease notably. Based on the parametric analyses, it is recommended to limit the central angle of simply supported composite girder below 45°, to apply an adequate number of diaphragms, and to design curved composite girders as fully shear connection specimens. Keyword  Curved composite girder · Finite element model · Beam theory · Torsion · Distortion · Interface slip

* Jia‑Ji Wang [email protected] Li Zhu [email protected] Ming‑Jie Li [email protected] Chao Chen [email protected] Guang‑Ming Wang [email protected] 1



School of Civil Engineering, Beijing Jiaotong University, Beijing, China

2



Department of Civil and Environmental Engineering, University of Houston, Houston, USA

3

China Railway Fifth Survey and Design, Institute Group Co. Ltd, Beijing, China



Abbreviations de The node displacement vector of the element F The equivalent load vector of the node K The element stiffness matrix N; NF The shape function matrix Q Concentrate load vector q