Wind-Induced Response And Wind Research Of Long-Span Arch Bridge In Construction Phase

With the constant improvement of the bridge design and construction level, the modern long-span Bridges span records have been refreshed, the increase of bridge spans, is bound to cause some new problems. Due to the construction of the bridge has not yet formed the final structural system, and compared with the state into a bridge, the rigidity of the structure is reduced greatly. Especially at the beginning of the main girder erection, the wind resistance stability of the structure is far difference compared with state into a bridge, the effect of wind on bridge construction stage is more prominent. Therefore, the wind analysis is necessary in the bridge construction phase.In this paper take an steel arch bridge construction process as example, do following research:(1) Establishing the structure model and analysising the dynamic characteristics, choose the appropriate method to simulate the stochastic wind field according to the local data.(2) Under the mean wind effect, using MIDAS/Civil conduct the linear buckling analysis and nonlinear buckling analysis, make a comparison to the result of the linear and nonlinear response of multiple working conditions.(3) Under the fluctuating wind effect, the linear time-domain analysis and the nonlinear time domain analysis was carried out on the naked arch condition by MIDAS/Civil, compare each displacement response and internal force response, calculate the dynamic coefficient, estimate the effect of the fluctuating wind.In this paper, the main conclusions are:(1) When the wind attack angle is not big before double arch rib closed, the response of the structure is not sensitive to the change of the wind attack angle. On one attack angle, the more closer the cross the more greater of the displacement.(2) The influence of fluctuating wind is larger than the average wind, and the significant influence of the transverse wind, followed by the vertical wind, downwind affect slightly. Under the fluctuating wind effect, the maximum displacement of the nude arch appeared in the cross near the Guanmen side, the maximum wind load component was near3#K lateral brace of Yangcheng side.(3) In four kinds of analysis method can reflect the downwind displacement value and the vertical wind displacement value is bigger, the transverse wind displacement value is smaller, and torsion angle value is small. In double arch rib fold stage, the downwind and vertical wind displacement need to have primary control, and transverse displacement can appropriate control, torsion control can be neglected.(4) During the construction process, the influence of fluctuating wind can not be ignored in the naked arch condition, through the time domain analysis get the theoretical displacement values and compare with the measured values found: nonlinear dynamic analysis is more accurate than the linear dynamic analysis.