Evaluation Of Bearing Capacity Of A Double Curved Arch Bridge And Research On Reinforcement Methods

At present,the bearing capacity of some strengthened double curved arch bridges fails to meet operation requirements due to the increase of traffic volume as well as the shortage of the double curved arch bridge structure in China.There are different degrees of damage,which threatens the safety of bridge operation greatly.As a result,secondary reinforcement is required.Therefore,it is of great significance to evaluate the bearing capacity of double curved arch bridges accurately and select the best secondary reinforcement method according to the actual technical state of bridges.A double curved arch bridge to be reinforced again is taken as the research background in the paper.The numerical simulation analysis method is adopted to evaluate the bridge bearing capacity and select reinforcement methods.The research content is mainly as follows.(1)According to the division of the bridge structure into the bridge deck system,the main arch ring and the arch building,the typical disease type and manifestation of each structure of the double curved arch bridge are summarized.The disease causes of the double curved arch bridge are drawn,including structural defects,low design load,insufficient construction technology and large traffic volume.(2)According to codes,the anti push stiffness of the pier and the main arch ring is calculated.It is inferred that the "double-arch effect" is not considered.The three-span double curvature arch bridge is divided into two side span and one main span.The bearing capacity of the main span and the side span is calculated respectively.It is inferred that the bearing capacity of the main span is insufficient.(3)The main bridge structure diseases and the material properties are detected.Bridge damages and disease causes are summarized.The bridge technical state level is evaluated according to detection results.The bridge static load test scheme is made.The bridge static load test is carried out.The deflection and strain results of bridge control section in load tests are analyzed to complete the evaluation on the bridge bearing capacity.(4)The common reinforcement methods of the double curved arch bridge as well as their advantages,disadvantages and applicable conditions are introduced.According to the actual situation of bridges in 2007,such as the selection of the reinforcement method of cross section increasing,the non interruption of traffic construction and the insufficient bridge management and maintenance technology,the methods of sticking steel plate,span reduction and the change of the section form of the main arch ring are taken as the reinforcement methods for co MParison.The finite element software of ANSYS is adopted to establish three kinds of finite element reinforcement models for the main span of the bridge respectively.The deflection value,maximum stress and structure natural frequency of the bridge control section under the load are taken as indexes to analyze the reinforcement effect of the three methods.(5)The effect of the three reinforcement methods is co MPared.Under the same load,the span reduction method is conductive to the reduction of the deflection of the arch rib of the arch crown section of the main span as well as the improvement of the deformation coordination ability of each arch rib.The drop range of the maximum stress is the greatest.The growth range of the overall stiffness of the structure is the greatest.Therefore,it is determined that the span reduction method is the best for the bridge.