Safety Evaluation And Research For Response Characteristics Of Prefabricated Simply Supported T-beam Bridges Under Heavy Traffic In Multi-region

In recent years, the bridge collapse accidents caused by overweight vehicles haveoccurred frequently. The heavy traffic loading moving on the bridge structure has significantinfluences on the performance and durability of the bridge. Most highway bridges are short ormedium span bridges, thus it is very important to study the dynamic response of short andmedium span bridges under the special heavy vehicle. This paper use BDANS (BridgeDynamic ANalysis System), which was developed by our research group, to calculateresponses of5common prefabricated prestressed simply supported T-beam bridges.Andbridge safety evaluation system was proposed for simply supported T-beam bridges underheavy traffic loading based on the measured data and response analysis results.The main contents are as follows:1. The traffic load data, which includes vehicle type, vehicle weight, axle loading,vehicle speed, vehicle length and lateral vehicle position, was collected by the HealthMonitoring System which located at the head of test Bridge. With the data, the special heavyvehicle traffic load case was defined and extracted; the driving characteristics of actual trafficflow load cases were analyzed; and the relationship between the actual traffic and the bridgedesign loads was discussed.2. The finite element models of5common prefabricatedprestressed simply supported T-beam bridges were established according to the <generaldrawing for highway bridge and culverts-superstructure of prefabricated prestressed concreteT-beam bridge(simply supported system)>， which was pressed by China CommunicationsPress in2006. The spans are20m,25m,30m,35m and40m, respectively. The dynamicresponses of the bridge structure were calculated according to D60, AASHTO, BS, and EN,respectively; and the design load values of Chinese code were evaluated.3. The traffic-bridge coupling vibration analysis module was adopted to calculate thedynamic responses of simply supported T-beam under the actual traffic flow collected in threeregions. And the results was compared with that calculated according to Highway Grade I ofD60. The relationship between the internal force effect of5simple supported T-beam bridges and the actual traffic characteristics of the three regions was analyzed.4. The features of over-limit internal force caused by special heavy vehicle traffic loadsin the three regions were analyzed. The influence of vehicle type, vehicle weight, drivingposition on the internal force of bridges was investigated. And taking traffic-bridge couplingvibration analysis system as a platform, to evaluate the safety performance of the threeregions’ bridges when heavy vehicles move across them according to the carrying capacityassessment method of Chinese code, thus to evaluate the bridge safety under heavy traffic.