Seismic Response Analysis Of Cable-stayed-suspension Pipeline Spanning Structure

In the past decade,the total mileage of oil and gas pipelines in China has increased by more than 76,000 kilometers.As the fifth type of transportation in modern society,oil and gas pipeline transportation projects have already played an indispensable role in the development of modern industry.The performance of pipeline structure is different from common highway bridges.Although scholars at home and abroad have studied cable-stayed span structure and suspension striding structure,so far,the seismic performance of cable-stayed suspension striding structures has been less systematically studied.What's more,the relevant norms,standards and regulations of the earthquake are not clear.In this paper,taking the cable stayed suspension span structure with the largest span of the same type as the engineering background,the dynamic characteristics and seismic response of the bridge are studied variously.The influence of the fluid-structure interaction between the pipe and the oil on the seismic performance is also discussed.The main contents and conclusions are as follows:(1)Briefly introduce the background,purpose and significance,development process and uniqueness of the cable-stayed suspension striding structures.Give the main forms of pipeline spanning in the oil and gas industry,and the advantages and disadvantages of various forms.Combining with engineering background,summarize the characteristics of cable-stayed suspension span structure.(2)Through the calculation theory of the calculation theory of cable-stayed suspension spanning structure,combining with practical engineering research background,the space model was built using Midas Civil.And its dynamic characteristics are analyzed.The results show that the first ten-order vibrations of the structure are mainly transverse bridge bending,and the longitudinal bridge and the vertical bridge are less appeared.For the response spectrum and the time history analysis,the influence of transverse seismic load should be considered.(3)According to the theory of response spectrum calculation and the selection of appropriate response spectrum and combination of operating conditions based on the specifications,the dynamic response of cable-stayed suspension structure under seismic response spectrum is discussed.Introduce the calculation theory of response spectrum,and select suitable response spectrum and combination of working conditions according to specifications.Discuss the dynamic response of cable-stayed suspension structure under the action of seismic response spectrum.The results show that the transverse bridge displacement of the structure changes significantly and it is symmetrically distributed.The main cable and stay cables play a role and change along with the direction of the seismic wave.In most working conditions,the pipeline is mainly subjected to axial loads,which is consistent with the design requirements of the oil and gas industry pipeline.(4)Analyze the time-history of the cable-stayed-suspension spanning structure.Consider the motion of the structure under one-dimensional,multi-dimensional,and multi-point excitation,and compare them.The results show that for one-dimensional consistent seismic wave action,the transversal bridge displacement response of the structure is more obvious.When the structure is subjected to multi-dimensional seismic waves,the internal force is changed greatly.The multi-point excitation changes the trend of lateral displacement,but the wave speed has little effect on the deformation and internal forces.(5)Aiming at the characteristics of structural oil transportation,a local model considering fluid-structure interaction is established,and the seismic time history analysis is performed.The overall seismic response before and after considering the coupling effect of oil and pipeline is compared.The results show that the fluid-solid coupling effect of oil and pipeline increases the amplitude and frequency of lateral displacement.It decreases the axial force limitedly,but increases the bending moment which is inconsistent with the design requirements.So the fluid-solid coupling effect has adverse effects on the structure,no matter internal force or displacement.