Study On The Aerodynamic Admittance Of Steel Box Girder With Wide Body

With the increasing of span suspension bridge, structural rigidity decreasing, buffeting response and internal force is growing, and thus bridge buffeting analysis increasingly important.The buffeting of bridge structure is mainly caused by atmospheric turbulence components.Turbulence caused by excessive bridge buffeting response in addition to the cause of structure of local fatigue damage, not comfortable and pedestrian traffic safety,even may cause structural damage directly.So,it’s important to A correct evaluation of bridge buffeting response,the aerodynamic analysis plays an important role in the calculation of bridge buffeting response.Cuntan Yangtze River Bridge uses a wide-body streamlined steel box girder,it’s aerodynamic admittance is relatively complex, in order to study the bridge aerodynamic admittance,Papers use section model wind tunnel test and theoretical analysis method,Cuntan Yangtze River Bridge on the wide-body streamlined steel box girder section aerodynamic admittance were studied.Its main contents include the following aspects:1.Review of the wind-induced vibration response analysis of bridge and the domestic and foreign research present situation of bridge buffeting,and to determine the meaning and significance of the mechanics of bridge deck aerodynamic admittance,Describes the bridge buffeting response analysis in the frequency domain, time domain theory and wind tunnel test measurement techniques, and gives the test scheme, the implementation basis is provided for the aerodynamic admittance of wind tunnel test.2.The main two levels describes the main factors buffeting response analysis:The one is turbulence wind characteristics of the atmospheric boundary layer, wind load and simulation test of fluctuating wind field;Based on two basic assumptions, and the other is the aerodynamic force buffeting response of the bridge girder cross-section.This paper expounds the three main aerodynamic admittance theory recognition method and the research methods of wind tunnel test.3.For inch beach wide-body box girder section model of Yangtze river bridge,Create a different grille turbulence field,As well as the application of high frequency balance and TFI cobra three-dimensional fluctuating wind instruments such as measuring instrument,it’s were measured wind spectrum and buffeting force power spectrum.Then using the method of equivalent aerodynamic admittance compute aerodynamic admittance of wide-body box girder, while the test results were analyzed and fitted withaerodynamic admittance test curve of wide box girder.Also systematically studied to the current average wind speed, wind attack angle and differentintensity of turbulence and the railing of the different ventilation rate parameters foridentification of aerodynamic admittance functions, we obtain some important results and conclusions.4. Buffeting force calculation model isintroduced,and thenestablished the analysis method ofbuffeting responses of long span suspensionbridge frequency domainbased on testaerodynamic admittance, and the beach Yangtze river bridge as an example, calculated the buffeting response of it.