Analysis Of Response And Vehicle Weight Limit Of Fabricated Box Girder Bridge Based On Extra-heavy Truck Load

As the main technical index of highway bridge design, the vehicle load directly affectssafety, economy and durability of the structure of bridges. The vehicle load in our country hasa characteristic of regionalism, so it is of great significance to do fine-analysis about responsecharacteristics of the bridge structure under traffic flow in different regions. This paperdepends on the national natural science fund project "Aerodynamic interference, fine analysisand assessment criteria of wind-random traffic flow-bridge system”(51278064). Based on thecollected data of traffic loads in Hebei, Zhejiang and Shanghai area, a system analysis andresearch have been carried out on the response characteristics of prefabricated box girderbridge under extra heavy truck load and vehicle overrun by means of numerical analysis andusing the random traffic–bridge coupled vibration analysis software. In view of the trafficload characteristics of the three areas, prefabricated box continuous girder bridges withdifferent span in "highway bridge general figure" are regarded as the basis of analysis. Themain research content is as follows:1. Compare design load value, number of lanes, impact coefficient, lateral reductionaccording to Chinese, American, British, European design specifications of the vehicle load;Different models of prefabricated box girder bridge model with various span are establishedto compare the response characteristics of prefabricated box girder bridge under eachspecification. Results show that the bridge design code in China is below the average level infour countries’specifications.2. Based on the measured data of traffic load, compare and analyze the loadcharacteristics of heavy truck in each region, and set up different model parameterscorrespondingly. The random traffic-bridge coupled vibration analysis software is used tocalculate spatial response of the typical box girder bridge, and the response will be comparedwith the standard design load effect to get response characteristics of different regions.3. Based on the mathematical models of vehicle load, select different ways for typicalvehicles to cross the bridge, calculate the corresponding vehicle weight when it reachesdesign load, and put forward a method to determine the reference value of limit load.4. Based on the weight limit of vehicles calculated in this paper, analyze the characteristics of internal force overrun in different regions. Finally based on the ultimatelimit state, evaluate the bridge safety whenvehicles are crossing.