Research On Hinge Joint Damage Evolution Rule And Evaluation Technology Of Concrete Hollow Slab Girder Bridge

As a typical small and medium span bridge,prestressed concrete beam bridge has the advantages of simple structure and convenient assembly,and is widely used in highway bridge construction.However,due to the influence of structural design,construction technology,service environment and other factors,the early-built concrete hollow slab-girder bridge has already appeared different degrees of damage,and the hinge joint is the key component of the transverse force transmission of slab-girder structure,the deterioration of its performance will aggravate the instability of the plate-beam structure.The deterioration law of the hinge joint damage is studied and a scientific and reasonable damage assessment system is explored,it is of great significance to the safety and durability of the plate-beam structure,especially the hinge joint.In this paper,the diseases of the concrete hollow slab girder bridges on some expressways in Jiangsu Province are investigated,and the typical diseases of the concrete hollow slab girder bridges are sorted out,it is considered that different types of diseases are related to each other to a certain extent,and hinge joints,as key members,directly affect the load-carrying capacity and transverse force transmission effect of the Slab Beam Bridge.Through the comparison and analysis between the theoretical calculation of the hinged plate and the deflection of the plate and beam obtained from the static load test of the bridge,it is revealed that the hinged joint concrete is not only a simple "hinge",but also can bear the multiple influences of tension,compression and shear.The multi-factor coupling deterioration law of concrete hollow slab girder bridge is analyzed by using vehicle overloading,damage of hinge joint,corrosion of reinforcing steel bar,and bearing void,etc.,the developing process of the hinge crack,the stress distribution of the bottom of the hinge joint along the Longitudinal Direction and the section outline,the deflection deformation of the plate girder,the stagger of the adjacent plate girder and the opening and closing of the plate girder are investigated.It is considered that the damage of hinge joint is mainly caused by cracking at the middle of the span,and the crack extends symmetrically to 1/4 span and 3/4 span with the increase of the applied load,until the phenomenon of hinge joint penetrating and the stress on the single plate girder is formed.Compared with the corrosion of reinforcement and the void of bearing,the overloading of vehicles and the damage of hinge joints have more influence on the performance deterioration of plate and beam structures,especially on the hinge joints.By comparing and analyzing the failure mode of the reduced-scale beam under the ultimate load capacity,the 8-meter prestressed concrete hollow slab beam was designed and poured,and the static loading tests of single beam and beam hinge system were carried out.The deterioration process of concrete hollow slab beam and hinge joint structure in different damage stage is summarized from the failure mode,crack developing process,deflection deformation,stagger,opening and closing,strain and so on.Based on the simulation and analysis of the difference of the influence line of the transverse distribution of the slab-beam structure under different locations and lengths of hinge joints,the joint joint damage grade(good,slight damage,medium damage,serious damage and complete failure)is characterized by the joint joint joint cooperative working coefficient,and the joint damage degree,misalignment,opening-closing and deflection ratio are used as testing indexes,the damage assessment system of hinge joint is established and applied to the verification of bridge.Based on the damage and deterioration model of hinge joint concrete,the corresponding years under different damage degree of hinge joint are predicted and analyzed.The research results of this paper can provide reference for the detection and evaluation of the hinge joint damage of the concrete hollow Slab Bridge of expressway,and have certain research significance and application value.