Research On Spatial Temperature Field And Effect Of Long-span Suspension Bridge In Natural Environment

Marked by beautiful shape and powerful span ability,long-span suspension bridges will increasingly appear in the type selection of both urban bridges and highway bridges.Suspension bridges are sensitive to temperature change.While radiated by environmental radiation such as solar radiation,air scattering radiation and ground reflection radiation,the components of suspension bridge will interrelate each other,making the solar radiation effect analysis of long-span suspension bridges even more complicated.Because the regulation of construction error and temperature effect elimination become more and more stringent,scholars all around the world begin to pay more attention to temperature effect of long-span suspension bridges.Suspension bridges are influenced by various environmental factors,so,it is difficult to reveal the mechanism of its temperature effect just through analyzing health monitoring data.Consequently,it is impossible to find out the common laws of construction error control and the temperature effect elimination from health monitoring data.Therefore,based on Guanting suspension bridge under construction,this paper uses FEM to finely simulate the spatial temperature field and temperature effect of suspension bridges in natural environment.The main work of this paper is as follows:1.Based on the three-dimensional occlusion theory and the heat transfer theory,the fine analysis method of spatial temperature field of long-span suspension bridge is put forward.The example suspension bridge is analyzed using the proposed method in this paper to find out the spatial temperature field distribution laws of long-span suspension bridge under the environmental radiations.Also,the vertical temperature gradient distribution of the steel-concrete composite beam is researched.At the same time,the change rules of different components temperature field difference of longspan suspension bridge are studied.2.Based on the spatial temperature field of the long-span suspension bridge,the variation law of temperature effect is analyzed.Also,the law of temperature effect affected by environmental factors such as daily number,wind speed,latitude and environmental temperature is studied.It is found that the tower tops of single span suspension bridge have the trend of moving towards middle span when the environmental temperature increases and the tower tops move towards side span while the environmental temperature decreases.Among the environmental factors,the environment temperature and the wind speed at the bridge site play decisive roles to the temperature effect of long-span suspension bridge.With the increase of wind speed,the increase amplitude of solar radiation effect of long-span suspension bridge gradually decreases and the time reaching the maximum solar radiation effect is gradually advanced.While the environmental factors change,the change amplitude of the longspan suspension bridge suspender force is less than 5%.The research results can provide theoretical basis for the construction error control.3.The moving load effect which contains the most unfavorable live load effect and moving vehicle effect is studied.By developing moving vehicle subroutine based on ABAQUS which can simulate the vehicle running along the most lateral lane,the response law of the suspension bridge under moving vehicle is studied.Through comparison of temperature effect and moving load effect,the relationship between the temperature effect and moving load effect of the suspension bridge is studied.The research results can provide technical support for the rapid judgment of suspension bridge health condition.