Study On Bearing Capacity Of Reinforced Concrete Arch Under In-Plane Stability

Stability is an important parameter in analysis of reinforced concrete arch bridge which is one of the main existing bridges in China. Each country is off its own design specifications for calculation of arc bridge stability.but the there are some drawbacks in estimating the mentioned parameter especially in Chinese design specification. Existing method of calculation for bridge arch bearing capacity under in-plane stability is implemented based on the theory of elastic buckling. By take the equivalent length of axial rod instead of arc length, the interaction of axial force and the shaft deflection does not take into account in considering the geometrical or material nonlinearity of the arch that may occur as the second type of stability so that the calculation result is estimated more roughly. Especially for the long span reinforced concrete arch bridge in which the reinforced concrete material behavior is inelastic these non-uniform values should not be neglected.Given to existing challenges for design and calculation of reinforced concrete arch in-plane instability, this study utilizes the ANSYS software associated with the related test data in literature regarding the limits of bearing capacity of reinforced concrete arch to investigate in-plane stability. The main research contents include:(1) Based on the optimization theory of arch axis, the reasonable arch axis coefficient of different kinds of structures under gravity is calculated. Considering the selection of element type, load, geometrical sizes of the structure and material constitutive behavior, the numerical analysis model of reinforced concrete arch for instability analysis is established. The numerical example is adopted to verify the reliability of the model which is used for elastic buckling analysis, geometric nonlinear analysis and double nonlinear analysis.(2) The influencing factors of the ultimate bearing capacity of reinforced concrete arch under in-plane stability which considering the deformation or nonlinear respectively is studied. And the regressive analysis of the influencing factors is made to obtain the regression equations which reflect the influence of nonlinearity on the load of the reinforced concrete arch under in-plane stability.(3) The influence of the initial stress on the reinforced concrete arch under in-plane stability is studied, and the influence factors are analyzed to establish the verified regression equation. The axial force of self weight in per slenderness ratio is adopted to study the axial force of reinforced concrete arch under in-plane stability, and the verified regression equation between them is established.(4) The influence of the calculation length coefficient of arch axis on the reinforced concrete arch under in-plane stability is studied, and the verified regression equation among calculation length coefficient, ratio of rise to span and span is established.The studies show that:At the time of instability analysis of reinforced concrete arch, The influence of nonlinearity is not only related to the span, but also by the influence of the ratio of length to width, moment of inertia, and rise-span ratio.Under the same conditions, the influence of material nonlinearity is greater than that of geometric nonlinearity. With the increase of span, The shaft force generated by the dead weight is more and more large, But as the span increases, The arch axis force produced by the reduction of the dead weight only has little effect on the axial force of the load. Under the three load conditions, with the increase of unit length and thin ratio under the self weight axial force, the axial force proportional to the unstable axial force is increased, To provide a reference for the judgment of losing stability.