Stress Response Analysis Induced By Buffeting Of A Long-Span Suspen-Sion Bridge Based On Distributed Wind Loads

As the critical project in the transportation system,the long-span bridges have been widely investigated and built over the world in recent years.However,owing to the charac-teristic of light and flexible structure,the long-span bridges,especially suspension bridges,may vibrate excessively under the strong wind loads.The buffeting is one of the wind-induced vibration and which is can’t be ignored.The buffeting response and the local stress response induced by it are analyzed in this paper based on the engineering background of Taihong Yangtze River bridge in Chongqing.The main work includes the several parts as follows:1 Firstly,the two 3-dimension finite element models are established by the universal fi-nite element software ANSYS with the spatial beam element and equivalent ortho tropic shell element,the dynamic characteristic analysis of the two models are conducted respectively,the results agree well with each other by comparison,which verified the correctness of equiv-alent shell-element model basically and can be used as the basis for the later investigation.2 A distributed buffeting load model is proposed.Based on the software ANSYS,the parametric design language(APDL)is used to realize the buffeting response analysis under the distributed wind load of the long-span bridge.By comparing the buffeting response re-sults of the spine-beam model and the equivalent orthogonal shell-element model,the relia-bility of the proposed distributed buffeting load model is verified,which provided the basis for the analysis of the buffeting stress response later.3 The local stress distribution of two models are investigated and compared,the results showed that the traditional spine-beam model is not suitable for local stress analysis.For the equivalent orthotropic shell-element model,the buffeting stress distribution of different sec-tions and key points is investigated under wind load with different average wind speeds.The results show that the stress of wind fairing is significantly greater than that of the top and bottom plates at the mid-span of steel box girder.In addition,the local stress will gradually increase and even grow nonlinearly with the increase of wind speed.