Reinforced Concrete Continuous Box Girder Under The Action Of Moving Load Damage Identification Research

Bridges with long hours of service inevitably appear damage,so scholars for bridge health problems also more and more attention,the purpose is to find a bridge there may be a hidden trouble and try to make a diagnosis and give treatment,and as a widely used in the practical engineering of continuous box girder bridge,damage due to diseases caused by the internal force distribution changes will affect the safety of the whole bridge.In this paper,the finite element theory is used to establish a three-span continuous box girder bridge model,the relationship between the change of the damage stiffness and the deflection difference curve is studied,the continuous box girder bridge under different damage conditions is simulated,the corresponding damage information is calculated and summarized,and the damage law is analyzed.The specific contents are as follows:(1)this paper introduces the possible diseases of reinforced concrete continuous box girder Bridges and the current methods of bridge damage identification at home and abroad.(2)briefly describe the finite element theory,and based on this theory,use MATLAB to compile the program model of the three-span variable height reinforced concrete continuous box girder bridge,and obtain the Angle,displacement and other internal force parameters of each node in the established model through calculation,laying a foundation for the following research on the relationship between the different damage conditions of continuous beams and the internal force parameters of the node.(3)by selecting deflection parameters that are more sensitive to the response,the calculated results in this paper are compared with the calculated results in MIDAS to verify the correctness of the model established in this paper.According to the calculationresults of the deflection quadratic difference,the curve variation rule of the three-span reinforced concrete continuous box girder under different damage conditions is analyzed,and the damage range,quantity and position are obtained by observing the curve variation rule.(4)in combination with the real bridge and the actual traffic situation,the finite element model of the three-span reinforced concrete continuous box girder bridge was established with ANSYS software,and the slope mutation law of the deflection quadratic difference curve under different moving load conditions was analyzed from a three-dimensional perspective,considering the actual load loading process of the vehicle.In the case of known local damage section,the damage information of different parts of local damage section of box girder was identified by summarizing the law of strain difference of roof,floor and web under different damage conditions.