| The performance evaluation of bridge bearings is currently mainly based on relevant specifications for visual inspection.This method has an intense subjectivity,and it is difficult to provide accurate decision-making assistance for bridge maintenance units and management departments,causing potential safety hazards.Existing standards and methods cannot check the force and deformation distribution of the whole bridge and the actual force and initial design value of the bridge bearing itself.This allows potential hidden dangers that may arise in intermediate links such as design and construction to be hidden and passed on to the operational stage,further creating more significant safety issues.In this study,based on the measured rubber uniaxial pull-up data of the plate rubber bearing,the Yeoh two-parameter model fitting was used to establish the natural rubber constitutive relationship.Studies have shown that the most significant impact on the working performance of the plate rubber bearing is the shear load,followed by a rotation,and again by axial compression.Regarding the problem of errors in the measured rubber compression and shear and the calculated data,the correlation verification and BP neural network were used to correct them.Set different working conditions,use the Pearson correlation coefficient method to study the determination of the damage index and the boundary system of the damage index,establish a plate-rubber bearing rating method,and give the threshold index corresponding to the five-level rating.Based on the measured vertical and radial deformation of the pot rubber bearing under compression,the Yeoh double-parameter rubber constitutive relationship is also used.The correlation index and sensitivity analysis were used to determine the damage index and the boundary conditions of the damage index.The performance rating method of this type of bearing was established,and the four-level rating and threshold of the performance of the pot rubber bearing were given.Studies have shown that the most significant impact on the performance of the pot rubber bearing is the non-slip shear load.The ratio of the vertical stiffness to the lateral stiffness of the pot rubber bearing varies significantly from 0 to 0.6 times the vertical design load.Within the range of 0.6 ～ 1.0times the vertical design load,the ratio of vertical stiffness to lateral stiffness tends to be stable.Similarly,based on the measured vertical and radial deformation of the spherical steel bearing under compression,correlation,and sensitivity analysis are used to determine the damage index and the boundary conditions of the damage index.Establish a performance rating method for spherical steel bearings,perform a four-level rating of the bearing performance,and give a threshold.Studies have shown that the non-sliding shear load and vertical load have the most significant impact on the working performance of the spherical steel bearing,while the rotation angle and the friction coefficient of the spherical crown have little effect on its stress.The study found that the stress of the lower bearing plate is related to the ratio of the shear load and the vertical load of the spherical steel bearing.When the ratio of shear load to vertical load is between 0 and 0.4,the vertical load plays a decisive role in the stress of the spherical steel bearing.When the ratio of the shear load to the vertical load is between 0.4 and 0.7,the decisive effect of the vertical load and the shear load on the stress of the spherical steel bearing has changed,and the specific performance is that the shear load gradually takes the decisive role.When the ratio of shear load to vertical load is 0.7 ～ 1.0 and beyond,the shear load plays a decisive role in the stress of spherical steel bearing.According to the above research results and conclusions,the SVM method is used to simulate and calculate a large number of bridge bearings.The input load and deformation are trained into three different learning models according to the established evaluation method,and the accuracy of the test results of the three models is above 95%,which meets the requirements of engineering use.On this basis,a bridge bearing evaluation system based on We Chat Mini-Program was developed to achieve rapid rating and evaluation of bridge bearings and to provide assistance in decision-making for maintenance departments. |
