Dynamic Characteristics And Seismic Nonlinear Time History Response Analysis Of Suspension Pipe Bridges

The spanning structure of pipeline suspension cable is a form commonly used in the transport of oil and gas pipeline.It is called as "throat" for the long-distance pipeline transportation of oil and gas,which is composed of main cable,suspender,wind cable system,truss bridge,tower and anchor system.Suspension pipeline bridge not only has the characteristics of large flexibility,low damping and uneven frequency spectrum,but also has the characteristics of light weight and small lateral stiffness,which is different from that of traditional suspension cable bridge.The unique dynamic characteristics of suspension pipeline bridge make it easy to produce more obvious dynamic behavior,which is more likely to cause structural failure and destruction.Due to the actual engineering,the damage of the spanning pipeline will affect the safety of the entire petroleum pipeline directly,which is more vulnerable to natural disasters than the ground pipeline.The earthquake disaster shows that the earthquake may lead to the destruction of suspension pipeline bridge,causing serious economic losses and environmental pollution.Therefore,it is of great significance to study the dynamic behavior of suspension pipeline bridge.To sum up,this paper takes the Yangbi River suspension pipeline bridge as the engineering background,aiming at suspension pipeline bridge with the unique spanning structure of suspension cable for the dynamic characteristics analysis and the impact of structural parameters for suspension cable pipe bridge’s dynamic characteristics analysis,seismic response analysis,seismic performance evaluation research and so on.This paper provides some suggestions and theoretical bases for the design of practical engineering structure and routine maintenance and inspection.This paper mainly from the following aspects to carry out research:(1)According to the engineering parameters of the Yangbi River suspension pipeline bridge and Midas/Civil software,the geometric nonlinear analysis method is used to obtain the initial state of the bridge under the action of gravity,which is prepared for the subsequent study of structural dynamic behavior;(2)The dynamic characteristic analysis of suspension pipeline bridge is carried out by using eigenvalue analysis method,and the natural vibration period and the vibrational mode of the Yangbi River Suspension Pipeline Bridge are obtained.The influence of the structural parameters such as the rise-span ratio,the tensile stiffness of the main cable,the tensile stiffness of the suspender,the tensile stiffness of the main wind cable,the distribution density of the suspender and the cable on the natural vibration characteristics of suspension pipeline bridge are studied.It is found that the change of the distribution density of the cable would cause a change of the order of the vibration modes of suspension pipeline bridge;(3)The nonlinear time history response analysis method is used to analyze the seismic response.And it is showed that different seismic wave input will has produced great influence on the seismic response analysis.So it is important to choose the right seismic wave.The seismic wave input method has a great influence on the seismic response result,and the seismic response of suspension pipeline bridge is more severe under the three-dimensional input;For long-span suspension cable bridges,the traveling wave effect is significant.When traveling wave was analyzed,the stress concentration of the pipe support at the beam end;The seismic response results under different working conditions are summarized,and the dangerous areas and possible failure forms of the pipe bridge system are obtained and some relevant countermeasures are proposed;(4)The damage model of suspension pipeline bridge is analyzed and summarized.The incomplete structure modes’ seismic response analysis of common suspension pipeline bridge are carried and compared with the results of the whole structure.The dynamic behavior of stability for damage mode is summarized under the action of earthquake.It is showed that a small amount of the failure suspender has little effect on the whole structure;Reasonable setting of the suspender and cable distribution density is conducive to saving materials and reducing costs,but also on the suspension bridge itself is conducive to earthquake resistance;The wind cable system plays an important role in improving the stability of suspension pipeline bridge.(5)According to the similarity principle,the experimental model of the Yangbi River suspension pipeline bridge is established,the influence of dynamic characteristics and structural parameters on dynamic characteristics of suspension pipeline bridge is studied by means of experiment and theory.By comparing the experimental and theoretical data,we can see that the error is within the allowable range,the correctness of the theoretical analysis is verified,and the correctness of the structural response analysis method and the idea of the subject is fully explained.