Analysis Of Static Wind Stability Of Large Span Pedestrian Suspension Bridge Under Different Wind Resistance Measures

Generally,the criteria for selecting the type of long span bridge as pavement for the pedestrians would normally be suspension bridge especially as scenic pedestrian bridges.Suspension bridges could be built on the mountains and canyons or in rivers and seas.And this can be attributed to its unique advantages,for instance,the great ability for spanning,nice appearance and pierless structure.By comparing with highway suspension bridges,stiffening girders of long span footbridge are relatively slender and fragile,hence,it only can be used for pedestrians.The width-span ratio and depth-span ratio of long-span pedestrian bridge will be dramatically deceasing with the increased span.Moreover,it will be extremely sensitive to wind load.For instance,in the canyon area,the environment of bridge sites especially for the wind environment will become more and more severe with the increase in the depth of the canyon and would be more likely to cause large amplitude wind-induced vibration.Thus,for this particular type of suspension bridge,the most important part during its design process is wind resistance design.The content of wind resistance could be basically separated into static wind stability and various wind-induced vibration such as buffeting and fluttering etc.As a fact,different measures also can be utilized to impede wind such as such as adding anti-wind cables,using a space cable system and adding a wind nozzle etc.In the past,lots of scholars deemed that thecritical wind speed of aerodynamic instability of bridge was generally lower than thecritical wind speed of static instability.For the previous research on wind resistance of the bridge,experts were mainly focused on the dynamic instability.After several decade development and some failed cases caused by the aerostatic stability during the calculation of aerodynamic instability,the static stability of bridge structures was gradually being recognized.However,for the design of pedestrian suspension bridge,there are very limited numbers of design specifications and analysis of static wind stability.It is hardly to find the report which is particularly analyzing how the static wind stability of the pedestrian suspension bridge would be affected by using different measures to anti wind.In order to achieve excellent static wind stability design of pedestrian suspension bridge,this article will be using scenic pedestrian suspension bridge with a main span of 300 meters which is under construction as case study.Based on the analysis of static wind stability of pedestrian suspension bridge,wind resistance cable and spatial cable system these two types of wind resistant structure will be mainly discussed in terms of the improvement of the static wind stability of pedestrian suspension bridge.The main task of this article are:(1)A linear method for the analysis of the static wind stability of long-span bridge has been introduced and the nonlinear factors for determining the static wind stability also has been explained.Particularly,nonlinear test methods of the static wind stability have been highlighted;(2)Based on the theory of nonlinear aerostatic stability analysis,ANSYS enables the calculation of the static wind stability of the pedestrian suspension bridge.By using APDL as language programming,the relative parameter has been edited and unitized.This program can be used to analyze the static wind stability of long-span bridge;(3)The result simulated by CFD is the static three-component coefficient of the pedestrian suspension bridge.Hence,whole process analysis of the static wind stability can be analyzed by using CFD system;(4)Static wind stability of 0°wind resistance cable(wind cable paralleled to the bridge surface),45°wind resistance cable and 90°wind resistance cable have been inspected respectively;(5)The static wind stability of long-span bridge has been introduced by inspecting the effects of three main cable within extroverted space cable system.(6)Wind resistant cable and space cable system these two anti-wind structure of the pedestrian suspension bridge have been compared laterally and longitudinally.