Simulating The Max Wind Velocity In Duration Of 100 Years Through Utilizing A Period Of Real Wind Velocity Records & Bridge Buffeting Analysis On Time Domain

Buffeting is the usual random vibration with the amplitude limited under natural wind. Although buffeting may not cause the bridge destroyed in whole, it can induce the fatigue for structure elements if it is not carefully dealt with. The excessive amplitude of vibration may also jeopard driving and pedestrian so as to make them not comfortable and safe. Therefore, to solve the problem about buffeting of bridge is concerned by people engaged in bridge engineering. One aspect about the studying of bridge buffeting is to simulating natural wind. If the result of its simulation is correct or not, it is directly concerned with veracity of bridge buffeting response. The method described in this paper may simulate real natural wind at the site of bridge using real wind velocity continuous records in short period and putting aside wind spectrum on the base of simulating merit or demerit, then buffeting response has been analysised.This paper calculated the maximum mean velocity of wind and correspondences fluctuating wind continuous chart in duration of 100 years using greatest table sequence record in 10 minutes every month(3~5years) in the basis of service life of the designed bridge and more probability. The method making a new task in simulating natural wind. Not to depend on old wind spectrum, it depends on real wind velocity continuous records. Greatest virtue of the method is always combined with practicality (wind record is real, site of record is real, the site of bridge is real), while the method for calculation of buffeting response is a ripe one梖inite method. The method for simulating natural wind field is convenience and workable.A structure analysis program for FEM is worked out to analyzing linear and nonlinear buffeting behavior in time domain. The program can be used to calculate the linear and nonlinear, static and dynamic responses of bridge. All of the results for bridges shown in this paper were calculated by using this program, while other program was used to check these results.Two actual long-span bridges are used as examples. One is the Guangzhou Yajisha concrete-steeltube arch bridge. Nonlinear analysis is not performed for this bridge since its rigidity. Firstly, its natural vibration characteristics are analysised, and the model used for calculating is checked at the same time. Then the static analysis under wind load is performed before linear buffeting analysis is done. The other bridge used in example is Wuhan Junshan Bridge that is a cable-stayed bridge. Its mid span is 460m while its stiffness is smaller. Therefore, besides doing the same analysis as in the above example, nonlinear buffeting analysis is also performed in time domain.Calculating results show the dynamic amplification coefficient is smaller when the stiffness of the bridge is larger and vices versa. The results of nonlinear analysis show, the affection of nonlinearity is little obvious for Junshan Bridge.