Nondestructive testing method of vertical prestressed reinforcement tension in box girder

The phenomenon of web diagonal cracks caused by excessive loss of vertical prestressing is particularly universal.In order to effectively test the tension value of vertical prestressed reinforcement,the exposed section of vertical prestressed reinforcement was analyzed.Space elastic support model was simulated for the supporting conditions of vertical prestressed reinforcement anchoring parts.When vertical prestressed tension changes,space elastic supporting stiffness and the vibration frequency will change accordingly.These changes can reflect the value of tensile force.Based on model test data,the nonlinear relationship of finishing rolling rebar between tensile force Tand the space plane elastic support model K was established.Extension test was used to validate the proposed method.Results show that this method is accurate,fast and convenient for engineering applications,and can effectively improve the construction quality of vertical finishing rolling rebar at box girder webs.