Study On The Calculation Method Of The Bearing Capacity Of Damaged Beam Bridges

Along with the rapid development of road transport, The number of bridge is constantly increasing.But for the rising traffic volume in recent years, more and more bridges are subjected to heavy load, some bridges show different degrees of disease. There are many forms of bridge in Our country, most of them are the reinforced concrete beam bridges. It is just a general phenomenon that diseases exist in beam bridge.The main bearing capacity of beam bridge is the superstructure.The disease of superstructure of reinforced concrete beam bridge takes factor to the decline of structural bearing capacity and serviceability, making the traffic have a big security risk. In order not to affect the normal operation of the bridge, a proper estimation of the bearing capacity of reinforced concrete beam with disease that is on in-service must be done and a method to solve this problem must be found. there are still no unified standard and method of how to calculate the bearing capacity at present. It is reduced and estimated by following the damage degree and personal experience, so the precision of calculation is quite bad.In order to find a better effective and reasonable calculation method, the scientific research project " The relationship between the concrete beam bridge damages and bearing capacity research" (subject serial number Y-030201) of the traffic office of Zhejiang is based on in this thesis. The various diseases of damaged concrete beams and the affection of them are analyzed. The calculation method of the beam's bearing capacity which have the diseases of concrete damaged and reinfored corrosion is researched. The briefly content of this thesis as follows:1. According to the damaged situation of existing reinforced concrete beam bridge, the typical disease characteristic of super structure of beam bridges of the highway is sum up. Then the cause of the typical disease and the impact on structure are analyzed and discussed thoroughly.2. The methods of calculating the bearing capacityof reinforced concrete beam and the mechanical properties of reinforced concrete are analyzed. The constitutive model of reinforcing steel and strengthened guidelines, concrete constitutive model and failure criterion of theory, the bond between steel and concrete slip mechanics are discussed thoroughly.3. The finite element analysis of bearing capacity of reinforced concrete beams and three of the existing finite element model are discussed. A simulation model applied to steel corrosion and concrete damage is selected. The impaction of concrete damage and steel corrosion on the bearing capacity of reinforced concrete beams are analyzed, then two diseases reasonable and accurate finite element simulation are proposed4. The reinforced concrete beam with concrete damage and steel corrosion are selected to carry on ultimate bearing capacity test, the stress and deformation of the controling section in the loading process and ultimate bearing capacity are determined. Considering the condition of actual component and the affection of the concrete damage and steel corrosion on mechanical properties and mechanical behavior of components, the capacity is calculated and analyzed by using the finite element method building disease-bearing capacity analysis model. The results of the finite element method and model test are analyzed comparatively and the reasonableness and accuracy of the finite element method are verified...