Investigation of the moment redistribution for steel – concrete continuous composite beams

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ABSTRACTThis study investigates moment redistribution phenomenon for pin ended double‐span steel‐concrete continuous composite beams and arise a question about moment redistribution for the continuous beams subjected to partially distributed or concentrated loading conditions. The overall objective of the study is to propose a methodology to fulfil the technical gaps adopted by Eurocode‐4, which considers the redistribution for only uniformly load condition. A robust iterative algorithm is developed to obtain moment‐curvature relations of the standard composite cross‐sections. Flexural stiffness‐curvature relations of the cross‐sections are predicted through the moment‐curvature relations. Flexural stiffness distribution along the composite beams is determined with curvature compatibility. Fourth order differential load‐deflection equation is evaluated with finite difference solution scheme for continuous beam conditions and variable flexural stiffness along the beam length. A non‐iterative incremental load‐deflection algorithm is developed to calculate moment distribution in continuous beams with variable flexural stiffness. A benchmark example is solved with Eurocode‐4 provisions to validate the developed algorithms. Moment redistribution from hogging (negative) zone to sagging (positive) zone of uniformly loaded double‐span continuous composite beam is illustrated considering the degree of flexural stiffness degradation in the composite medium. A question is arisen for moment redistribution in the continuous beams subjected to partially distributed or concentrated loading conditions.