Study On Safety Evaluation Of Large Transport Vehicles Passing Bridge

In recent years, with the rapid development of the national economy, some key construction projects focused on the national economy and the people’s livelihood have been started, which requires a large shipment to undertake the transportation support taskof key equipments, those equipments has characteristics such as overweight, long,wide, high, high value, non disintegration etc. Therefore, whether the equipment can reach the destination safely and quickly, whichwould directly related to the the smooth implementation of the project, as well as make great impact on the development of the national economy.Because of the particularity of large transportation would increase the difficulty of highway transportation , and make serious impact on safety of bridges, so, how to protect the safety of the bridge and ensure transportation safety, economy, quickly arrived the destination, has very important significance.This paper made research on the problem of carrying capacity evaluation of bridges when large transport vehicles passing, then put forward the corresponding countermeasures,the main research contents and results of this paper are as follows:（1）Aiming at bearing capacity evaluation of large transportation along the bridge, this paper summarized the conventionalevaluation methods of the bearing capacityof bridge .Analyzes the limitations of those conventional evaluation methods, then put forward the quick evaluation method for large transportation bridge.（2）Around the core problems such as values of related technical parameters in evaluation and calculation of bridge bearing capacity etc. This paper analyzed the safety reserve of existing bridge bearing capacity theoretically. Combining with calculation formula in <Code for inspection and evaluation of bearing capacity of highway bridges and culverts> （JTG/T J21-2011） , this paper put forward the conclusion that using Comprehensive influence coefficient K of bridge bearing capacity with different technical grade to raplace the 4 load carrying capacity reduction factors Z₁、ξ_e、ξ_c、ξ_s in the code. Then proposed the simplified formula for load carrying capacity evaluation of large transport vehicles γ₀S ≤ R(f_d, a_dc, a_ds)K Analyzed the load transverse distribution coefficient of the main girder, the impact coefficient and the coefficient of load combination, and determined the load combination formulaγ₀S/K = γ₀（1.2×SG+1.1ST）/K≤R(f_d,a_dc, a_ds), basing on the rapid evaluation of large transportvehicles crossing bridge.（3） Discussed the evaluation methods and steps of the large transport vehicles crossing the bridge, combining with the engineering examples, provides the reference for the colleague.