Health Mofo Lniinto Jriianngg A Mppelnic Batriiodng Eresearch

With the development of our national economy, the traffic volume and largetonnage vehicles are increasing. To ensure the normal use of roads and bridges andreduce the occurrence of accidents, reasonable and effective bridge detection andreinforcement, and enhancement of carrying capacity of existing bridges, is the onlyway which must be passed to ensure the normal operation of roads and bridges in China.Taking Near the Lin jiang men Bridge as an example, this paper carries out andanalyzes a range of tests in conjunction with the finite element model of Midas Civilbridge, such as the visual examination, strength test of the concrete, linear detection ofbridge deck, dead load cable force test, static load test, dynamic test and the modalparameters test of main bridge, starting from the factors influencing the durability of thebridge.The results show that:(1)Repairs are needed if there is cable corrosion and part of the concrete crackexceeds regulatory requirements by0.1mm.(2)Concrete strength is47.2~57.5MPa, meeting the requirements of50#concretestrength grade. The electrical resistivity of concrete is87k·cm and85k·cm, whichshows that steel corrosion speed is very slow.(3)The stress coefficient ranges of girder, crossbeam, main tower,0.27~0.81,0.33,0.71~0.91respectively, and the main bridge deflection coefficient,0.41~0.65, meet therequirement of no more than1. The stress coefficient of the girder web,1.3~3.54, ismore than1, and reinforcement is needed.(4)Dynamic load force coefficient is0.97~1.54, and cable total stress is tensilestrength0.60~0.69times tensile strength, which shows cable safety reserve is low.(5)The girder strain dynamic increment,0.090~0.120, the first order vibrationfrequency of bridge vertical of main bridge,1.363Hz, and the correspondingdamping ratio,1.665%, is larger than the theoretical value, which indicates that bridgestiffness is good.(6)The bridge can meet the safety load requirements of the design load auto-Super20, Trailer-120. If the existing motorway is increased from4to5, the bridge canonly meet the demand of auto-20, while the motorway remains5, a tonnage limit of30tons must be strictly put.