Research On Wind-induced Responses Of Long Span Pipeline Suspension Bridge

With its beautiful appearance, long span, good economic indicators, the advantages of mature design and construction, suspension bridge has been widely adopted for oil and gas pipeline bridge. Compared with ordinary suspension bridge, pipeline suspension bridge's stiffness is smaller, wind-induced vibration problem is more prominent. In this paper, taking one oil and gas pipeline suspension bridge as example, those keypoints had been studied on: dynamic characteristics, aerostatic response, flutter stability and buffeting response. The main work and conclusions are as follows:(1) Through the method of link elements initial strain iteration, the bridge reasonable linear shape has been obtained. The dynamic analysis has been carried out, the design parameter change to the pipeline hanging bridge self oscillation characteristic influence has also been studied. The result indicated:The pipeline suspension bridge mode is crowded, the vibration characteristic is complex; The frequency ratio of torisional to vertical bending is low, the lateral rigidity is weak, the low-order mode of vibration is by the stiffening girder vibration lineup primarily; The installment of windcables can obviously enhance the structure lateral rigidity, increases the wind cables pretension strength to be possible to enhance the structure lateral bending and the torsional rigidity, reduce the wind resistant rope inclination angle to be possible to enhance the structure to set upright the curved rigidity; The establishment conjugate cable is big to the higher order vibration abatement function.(2) The paper obtained three force component coefficients through the static stage section model wind tunnel test, analyzed the influences on three force component by grate plate. The paper has carried on the static wind stability analyses and the still wind response analysis using the increase with the inside and outside twofold repetitive process. The result indicated:The pipeline suspension bridge's aerostatic divergence process is result from the aerostatic load and the structure nonlinearities; The wind load initial angle of attack increases, the static wind stability reduces; The establishment of windcable may enhance aerostatic divergence speed by 20%; The initial angle of attack, the additional angle of attack, the cable system wind load, the windcable' establishment has influences on the aerostatic response. (3) The paper has obtained flutter critical wind speed under the different angle of attack through the section model dynamic wind tunnel test, has carried on the appraisal to the flutter stability; has distinguished the smooth flows flutter derivative using the least squares method, provides the self-excitation force parameter for the buffeting response analysis.(4) The paper has simulated the entire bridge's pulsation wind field using the WAWS, has established the entire bridge buffeting strength model using the Davenport buffeting strength theory, has been realized through the ANSYS in matrix27 element to the self-excitation strength aerodynamic rigidity and damping simulation, considered that aerodynamic and geometric nonlinearity, has carried on the buffeting response time domain analysis using the transient state mechanical analysis.