Calculation of Effective Axial Stiffness of Cracked Reinforced Concrete Tension-Flexure Members Under Temperature Reduction

The effect of temperature on ultra-long concrete structures is very significant. Bending cracks may occur on the structure under service loads, while the tensile stress generated by temperature effect will further crack the structures, and thus the stiffness of the members will be reduced significantly. A simplified elastic analysis method was proposed in the paper, which considered the stiffness reduction of reinforced concrete tension-flexure members under temperature effect, and could obtain the effective axial stiffness of cracked tension-flexure members through simple iterations. The internal force of a single-span statically indeterminate beam under combined service load and temperature reduction was analyzed with the proposed method and finite element program ANSYS respectively to obtain the axial force versus temperature effect curve. The comparison between these two methods indicated that the calculated axial force by proposed method coincided well with finite element modeling results. The proposed simplified method could avoid complicated nonlinear analysis and had reasonable feasibility and accuracy.