Evaluation method of shear capacity of aged reinforced concrete beam bridges

Abstract

The invention discloses an evaluation method of shear capacity of aged reinforced concrete beam bridges, which obtains an initial time of corrosion of reinforcing bars in concrete based on a Fick second diffusion law, and obtains an action force of reinforcing bars at a shear inclined crack by considering the reduction of the cross-sectional area of the corroded reinforcing bars and the reductionof the yield strength of the reinforcing bars; the compressive strain at the loading position of the beam top is obtained from the assumption of plane section. According to the stress balance equationof shear-compression section of beam, a formula for calculating the height of compression zone of concrete at the top of critical inclined crack is established. By integrating the height of compression zone, the horizontal force of a non-cracked concrete section is obtained, and the action position thereof is determined by the moment relation. Based on the ultimate shear equilibrium theory, the calculation method of shear bearing capacity of aged reinforced concrete beam bridges is put forward according to the element equilibrium relationship of isolator in shear-compression section of beam.The prediction method of the invention is reasonable and has strong popularization, and can provide technical support for safety evaluation of the service concrete beam bridge.

Description

technical field [0001] The invention relates to the field of safety evaluation of bridges in service, in particular to an evaluation method for shear bearing capacity of aged reinforced concrete beam bridges. Background technique [0002] Corrosion will reduce the cross-sectional area and strength of the steel bar, and the expansion force generated by the increase in the volume of the corrosion product will cause the concrete to rust and crack, reduce the bond between the steel bar and the concrete, and lead to the degradation of the structural bearing capacity. Existing studies on the influence of steel bar corrosion mostly focus on the flexural performance of the structure, and there are relatively few studies on the shear performance. Since the shear reinforcement is in the outermost layer of the reinforcement skeleton, it is more prone to corrosion; at the same time, compared with the bending reinforcement, the diameter of the shear reinforcement is relatively small, so ...

AI Technical Summary

Problems solved by technology

The shear mechanism of reinforced concrete structures is complicated and there are many influencing factors. At present, there is no universal shear theoretical calculation and analysis method. The current design code still uses a semi-empirical and semi-theoretical model for the calculation of the shear capacity of beams with web reinforcement.

[0003] Aiming at the above technical problems, some scholars studied the degradation law of the shear performance of corroded reinforced concrete structures through experiments, and proposed corresponding calculation methods, but mainly for corroded beams without web reinforcement or only stirrups

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