Research On Bearing Capacity And Dynamic Performance On Existing RC Railway Bridge

Known as the arteries of the national economy, the railway have made considerableprogress, since the founding of China’s railway industry. As the large permanent structures,railway bridge have a complex structure, technical and long construction duration, and alsohave the high value. Compared with the development of the railway form1970s, a largenumber of small and medium reinforced concrete simple-supported railway bridges werebuilt, most of these bridges are currently in serving or have quit working.The existing bridges in serving, which are bearing the long train dynamic loads and theeffects of rain, temperature change, atmospheric environment, had bad technical condition.Without timely detection and prevention, these bridges will risk the huge hidden danger.Therefore, the research on the bearing capacity of the existing bridge and dynamicperformance, adding the testing, evaluation, and decision of continuing use,requiringmaintenance or renovation, is of great significance.This paper base on the previous researches, referring the Qingjiang River RailwayBridge of Baoji testing project. The static load and dynamic load test have made to theexisting reinforced concrete simply-supported girder bridge. According to the characteristicsof bridge, we choose the single∏beam model for computer finite element. And somemesures have made to Qingjiang River reinforced railway bridge correspondingly. Details areas follows：1、Methods of performance assessment for existing reinforced concrete bridgesIntroduces for the present status of study on evaluation method of bridge, illustrates forthe performance assessment process and methods of bridge. Pointing out that assessment forexisting reinforced concrete bridges including visual inspection of the deck, concrete andsteel performance testing performance, etc.2、Case studyWe show the engineering background of this test, introduce the contents and issues ofvisual inspection of bridge. The internal combustion locomotives have been used on staticload and dynamic load tests of bridge. So the strain, deflection, amplitude, frequency, velocity, acceleration reflection for bridge static and dynamic properties of measured data can beobtained, and the finite element modeling and reinforcing measures experimental thereforhave proof.3、The building and analysis for bridge finite element modelIntroduces of the basic principles and processes for solving finite element softwareMIDAS/Civil have been made. We establish a single∏beam finite element model and useit to simulate the bridge force, section stresses, deflections and compare it with experimentaldata.Try to verify the validity of bridge model. Drawn modal analysis of the bridge and getthe natural frequency and the first8-order mode shape; analysis the variation of deflection,prividing references for similar analysis of dynamic performance of bridge bearing capacity.4、 Reinforced concrete bridge reinforcementCombining the bridge test analysis and finite element simulation analysis, somemaintenance measures have given to concrete surface and cracks, bridges faces, piers,abutments, walkways, slope protection. To improve shear capacity of beam and to enhancethe integrity of the beam, as well as complement for bearing capacity of corroded decay,made a main beam reinforcement with carbon fiber. Discussed the plan of adding diaphragmplate to enforce the beam stiffness.