Detection And Safety Evaluation Of An Operational Cable-stayed Bridge

Cable-stayed bridge with span a wide range of application, shapely configuration, and from the last century after 80 time, was researched and the first used, at present has been built hundreds of, then the span of record is constantly being refreshed. But because of the comprehensive effect including at that time the design standards, construction level, the long-term overload, poor maintenance and repair, accident, and structural factors such as lack of awareness, some bridges have appeared the cable aging, anchorage failure and other diseases in the period of use, many bridges have been carried out the construction of cable changes, still a large number of bridges in service need been repaired and reinforced. Based on the background of a cable-stayed bridge project, the focus has important engineering significance to the bridge operating state detection and the safety performance evaluation.Taking a cable-stayed bridge as the basis, of the bridge has a routine inspection and special inspection, on the basis of test results of the bridge working state has been carried on the preliminary determination. The bridge bearing capacity was checked according to the specification, a comprehensive evaluation of the bridge was conducted, by using finite element software modeling, the static and dynamic performance of the bridge is simulated and calculated, and through static load, dynamic load test, the work behavior of the bridge was thoroughly inspected, the typical response of the bridge is obtained, under the most unfavorable loading state the test results show that for the main measuring point deflection and stress the check coefficient is equal to 0.85, the maximum residual displacement and strain are less than 20%, under the maximum test load, girder bottom for the cable-stayed bridge no has cracks, bridge foundation without the occurrence of unstable settlement and displacement. Pulse test results show that, the vertical bending natural frequency is 1.76 Hz, greater than the calculated frequencies, indicating that the bridge girder stiffness to meet the design requirements. The first 3 vertical modes of the damping ratio were 4.32%, 2.59%, 3.53%, the measured impact coefficient in the span middle cross section is between 1.05 ~ 1.12, in the rational range of similar bridge. Therefore, bearing capacity satisfies the design load level, and automobile-20 hang-100 requirements, structure is in the elastic state.