Research On Shear Performance And Reinforcement Technology Of Hollow Slab Bridge Hinge Joints

At present,the number of simplly-supported beam Bridges in service is huge and the common diseases are mainly hinge joint concrete falling off,longitudinal cracks at the bottom of the main beam,main beam dislocation,bridge deck Pavement damage,some of the more serious in the veneer stress.The main reasons for these problems are as follows: first,the design standards at that time do not meet the current vehicle load requirements;Second,the construction process is rough(not chiseled wool);Third,the bridge is in bad environment;Fourth,the bridge reinforcement is simple.In order to reduce the disease of hollow girder bridge,the commonly used reinforcement methods in China are hinge joint reconstruction,thickening bridge deck Pavement,adhesive steel plate or carbon fiber plate.The effect of the above reinforcement method is not obvious,hollow girder bridge will occur disease after a few years.Therefore,it is necessary to conduct a more systematic study on the mechanism of hollow beam hinge joints.In this Paper,the damage criterion and failure criterion of bond element are defined by concrete test block test and cohesive force model,and the shear surface is replaced by bond element.The influence of different side pressure,different shearing depth and different concrete strength on the shear strength of concrete is studied.The influence of cement mortar,epoxy resin adhesive,weather resistant adhesive,steel adhesive and carbon plate adhesive on the shear strength of jointless specimens was also studied.Aging test of various cementitious materials;Through the finite element simulation of hollow plate hinge joint steel plate reinforcement,carbon fiber plate reinforcement,joint reinforcement,large hinge joint,etc.Based on the cohesive force model,this Paper adopts the method of combining numerical simulation and experiment to achieve the following results:(1)The shear strength of concrete specimens can be improved by increasing the gouge depth and interlayer strength of concrete,but the weak surface of concrete is still at the interface,and the concrete cracks along the interface under shear force.The corresponding constitutive relations and key constitutive Parameters of new hinge joint specimens with different concrete strength,side pressure,thick Ness of chisel and shape were obtained through concrete shear test.Through material aging test,the best anti-aging material is steel structure adhesive.Based on the shear test of concrete,the shape of the optimal new hingeless joint specimen is double broken line,and the constitutive relations and key constitutive Parameters of the cementing material with the optimal shear resistance are obtained under the optimal shape of the new hingeless joint.(2)Based on the cohesion model,a two-dimensional concrete specimen model was established to simulate the influence of different thick Ness of chiseled wool,different strength of concrete and different side pressure on the shear strength.The difference between the numerical simulation results and the experimental data was very small,indicating that the cohesion model is feasible to simulate the concrete shear specimen.When the new hinge joints of different shapes of epoxy resin structural adhesive,carbon plate structural adhesive and steel structural adhesive are destroyed,the failure surface is improved,not only cracking along the interface of the hinge joints,but also cracking of the test block itself,indicating that the new hinge joints of different shapes have good shear performance,and the shear cracking mode of the hinge joints is improved to a certain extent.The aging resistance of weather-resistant structural adhesive is excellent,but the shear strength of weather-resistant structural adhesive is lower than that of ordinary concrete,and the cracking mode of hinge joints is not changed.Various Parameters rubber(except weather resistance rubber)a new type of hinge joint shear strength of the specimens increases,that under the effect of different cementing materials,the hinge joints of shear bearing ca Pacity is greatly improved,the possibility of cracking co MPared with cement mortar is reduced greatly,the shear effect optimal for glue stick steel structure without the hinge joints specimen,it is larger than that of ordinary concrete specimen shear strength by about 48.8%.(3)The effect of hollow slab hinge joint combination is the best,and the ultimate cracking load of hollow slab bridge is increased by 35.2% than that of unreinforced hollow slab bridge.The rigidity and deflection of hollow slab can be improved obviously by replacing large hinge joints.New hinge joints can greatly improve the overall concrete hollow plate shear performance and effectively improving the overall stiffness of the hollow plate,and the improvement of failure face,not just the hinge joints in hinged along the interface crack,hollow plate itself will craze,a new type of hinge joint shear performance good,to some extent,improved the shear fracture model hinge joints.