Techno Press


Steel and Composite Structures   Volume 19, Number 5, November 2015, pages 1203-1219
DOI: http://dx.doi.org/10.12989/scs.2015.19.5.1203
 
Distortional buckling calculation method of steel-concrete composite box beam in negative moment area
Wangbao Zhou, Shujin Li, Lizhong Jiang and Zhi Huang

 
Abstract     [Full Text]
    'Distortional buckling' is one of the predominant buckling types that may occur in a steel-concrete composite box beam (SCCBB) under a negative moment. The key factors, which affect the buckling modes, are the torsional and lateral restraints of the bottom plate of a SCCBB. Therefore, this article investigates the equivalent lateral and torsional restraint rigidity of the bottom plate of a SCCBB under a negative moment; the results of which show a linear coupling relationship between the applied forces and the lateral and/or torsional restraint stiffness, which are not depended on the cross-sectional properties of a SCCBB completely. The mathematical formulas for calculating the lateral and torsional restraint rigidity of the bottom plate can be used to estimate: (1) the critical distortional buckling stress of SCCBBs under a negative moment; and (2) the critical distortional moment of SCCBBs. This article develops an improved calculation method for SCCBBs on an elastic foundation, which takes into account the coupling effect between the applied forces and the lateral and/or torsional restraint rigidity of the bottom plate. This article analyzes the accuracy of the following calculation methods by using 24 examples of SCCBBs: (1) the conventional energy method; (2) the improved calculation method, as it has been derived in this article; and (3) the ANSYS finite element method. The results verify that the improved calculation method, as it has been proved in this article, is more accurate and reliable than that of the current energy method, which has been noted in the references.
 
Key Words
    steel-concrete composite box beam; elastic foundation beam method; distortional buckling; rotational restraint stiffness; lateral restraint stiffness
 
Address
(1) Wangbao Zhou, Shujin Li:
School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, China;
(2) Lizhong Jiang, Zhi Huang:
School of Civil Engineering, Central South University, Changsha, 410075, China.
 

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