Analysis Of The Influence Of Vehicle Overload On Bridge Structure And Service Life

With the improvement of China's economic level and the development of transportation,many overloaded large and medium-sized trucks operate on a large number of bridges built in China,posing a great threat to the safety and service life of bridges.In order to ensure the safety of the bridge structure under actual operating condition,it is necessary to quantitatively study the fatigue damage of the bridge under the action of overloaded vehicles.The management and maintenance Suggestions obtained from the analysis are of great practical significance to ensure the safety and reliability of the bridge and the normal traffic.On the basis of the fatigue theory,the finite element model of shuiyangjiang bridge,a long-span cable-stayed bridge in xuancheng city,anhui province,was built with the finite element software Midas/Civil to analyze the forces under the design load on the model under the completed state of the bridge.The vehicle load was simplified to the dynamic load applied on the main beam to analyze the dynamic response of the vehicle crossing the bridge.The stress time-history curve of the cable was obtained.The method of calculating fatigue damage was used to compare and analyzed the cable fatigue damage caused by the bridge crossing of five typical vehicles under different over-load rates.Then,according to the probability distribution of actual highway traffic conditions obtained through relevant investigation and research,the random vehicle load obtained by Matlab software programming was used to simulate the actual traffic flow.The fatigue damage of the cable under the random vehicle load was compared with that under the design live load to calculate the service life of the cable under the actual operation state.Based on this model,the influence of overload vehicle on the deflection of girder was analyzed.Finally,through the simulation of overloaded vehicles crossing bridges at different speeds and spacing between workshops,the driving conditions of vehicles with the smallest fatigue damage to bridges are obtained.Based on the data and conclusions obtained,some management suggestions on bridges and vehicles are put forward for the relevant management departments of the bridge.