Study On Behaviors Of Hinge Joints For Fabricated Reinforced Concrete Simply-supported Plate Girder Bridges

At present, there are a great number of fabricated reinforced concrete plate girder bridges in service, whose hinge joints have significant effects on co-working performance between their plate girders. Currently, a large number of bridges of this type with damaged hinge joints exist, which lead to the poorer performances of plate girders. Although the hinge joints are well strengthened in their detailing, normally their damages still happened. It is essential to make research to solve this problem.This thesis begins with a review on the development of hinge joints for fabricated reinforced concrete plate girder bridges and their previous related researches, and points out several currently existed problems, then determines a research method for them. The analysis in the thesis focuses mainly on the behaviors of hinge joint surfaces. Firstly, the distribution of contact stresses and their magnitude according to moving load in the surfaces between hinge joints and plane girders are obtained by simply modeling two girder bridges using ABAQUS, finding most unfavorable positions of load and stress controlled zones. And some factors affecting the stress values are also discussed. From these results, the vertical shear stress and nominal stress of hinge joint's surface A and surface B reach their maximum values on the positions where load exerted. The stress distribution graph from calculation results shows that there only has a short length range for the high stress along bridge span. The closer the load position is to the hinge joint, the shorter the high stress length range is, and also the higher the stress value is. It is about one sixth of the bridge span when load moves close to the hinge joint. Their longitudinal shear stress reaches the maximum value at one twelfth spans of the bridges. There are many factors affecting stress magnitude, among them deepening bridge's hinge joints and thickening its pavement can decrease these values efficaciously. Secondly, the bond of hinge joint-girder concrete can be thought as one type of new-old concrete bonds, while the bond performance has its own features due to hinge joint behaviors. A fabricated reinforced concrete plate girder bridge is modeled by ABAQUS with taking into consideration of non-linearity of material to simulate the failure process of contact surface adhesion in most unfavorable load positions. The calculation results show that the hinge joint's surface B is weaker, whose normal direction bond is more likely to fail, and the vertical shear bond of the surface A is also weak. The vertical shear is mostly transferred by the normal stress of the surface B and the vertical shear stress of the surface A, whose bond behaviors of the two together determine the strength of the hinge joints. Finally, the performance of hinge joints with different reinforcement bar detailings is analyzed, reflecting that the bars in hinge joints should be positioned relatively lower. Basing on bond behaviors of hinge joint-girder concrete and the existed analytic conclusions, the treatment method of hinge joint surfaces is produced, and a new hinge joint detailing and its reinforcement method are also proposed.The conclusions given in the thesis can be used to design or strengthen this type of bridges. Along with more and more appearance of hinge joint damages in fabricated reinforced concrete plate girder bridges, the research undoubtedly has its unique engineering significance and extensive practical prospects.