The Research Of Wind-resistant Stability Of Pedestrian Suspension Bridge

With the rapid development of national economy and technologies,suspension bridges are developing towards the target of longer span and slimmer structure.Thus posing a threat to the dynamic and static response resulted from the wind load.This paper take a suspension bridge as an example which study the Wind-Resistant Stability in the static and dynamic responses.For the static: this paper analysis the suspension bridge use Two-dimensional Linear Static Wind Instability theory.For the first,take the tunnel test of this suspension bridge,with the result of the test evaluate the Pneumatic stability.Besides we can get the wind-load of every wind speed.The wind-load is used to the finite element model in which we can analyze the aerostatic stability of the suspension bridges.There are some factors to the aerostatic stability of the suspension bridges,this thesis analysis the impact of initial angle of wind-load,the impact of calculation,the cable wind-load,the impact of sag to span ratio of the suspension bridge,the impact of wind-resistant cables angle,the impact of main cable pull,the thesis shows that:(1)The critical wind speed of the suspension bridge is reduced with the increase of the angle of attack,and the slope of the displacement and displacement curve increases with the increase of the angle of attack.Under the initial negative attack angle static wind load,the wind speed becomes larger,and the slope of the structure displacement wind speed curve has no sudden change,that is,the static wind instability will not occur.The bridge structure will be overloaded by the wind load,which is more than the damage of the ultimate bearing capacity of the bridge.At the positive angle of attack and 0 degree of attack,the slope of structural displacement curve is abrupt,that is,the phenomenon of static wind instability occurs,and the instability wind speed decreases with the increase of initial wind attack angle.(2)Sag to span ratio of the main cable impact the ability of the wind resistance,when the sag to span ratio of the bridge is small the displacement of the stiffening beam is low and the ability of the wind resistance is good.(3)Calculation shows :the greater the angle between the wind resistant cable and the horizontal plane and the tensile force of the wind resistant cable in a certain range,the better the resistance to wind.But their effects on the wind resistance of the suspension bridge are becoming less and less obvious,so it can be calculated according to the original design? If it is difficult,the angle of the wind resistant cable can be 45 degrees and the tensile force can be 1.5 times the original tension.(4)According to calculation and analysis,the aerodynamic stability of the bridge is good,and the flutter stability and the stability of the galloping can meet the requirements of the standard.