Abstract
Problem statement: When earthquake is occur, many damages were occurred in pipelines that San Francisco (1906) and Manson (1908), Kobe (Japan) and ate are samples of this topic. So many researchers studied on the pipelines and dynamic forces. Approach: Determine static and dynamic performance parameters of the pipeline and the surrounding soil such as static stiffness, dynamic stiffness, damping and additional mass share of soil which take part with pipe mass in dynamic performance. In the static case relationship between friction forces and joint deflections in a buried element pipe had be calculated and with using of some experimental results and results are compared together. For dynamic cases, Dynamic equilibrium equation of pipeline element axial vibration in continuous system, with neglecting the effect of soil mass share which participates in producing vibration and with considering of it were abstained and values of displacement and forces were calculated. In continuous, these formulations were process for many cases and were drawn in graphs for comparison. Results: Stiffness for ω/ωn 0.5) which the ratio becomes more than 1. Finally for ω/ωn>1, the ratio of dynamic to static stiffness rises rapidly and by increasing the additional mass, the value of dynamic stiffness in case of ω/ωn>1 would increase highly. Conclusion: The static performance between soil and pipe is nonlinear in axial direction and when the hysteric dominates grows, the value of force dominates between soil and pipe and dynamic stiffness would ascend. Also by increasing damping ratio, the dynamic stiffness would increase too however it depends on the static to dynamic stiffness ratio and the damping ratio.
Highlights
The purpose of this study is to study on the static and dynamic properties of buried pipeline and surrounded soil in axial direction due to harmonic dynamic vibration
The formulation and experimental methods, to find a method for determining dynamic stiffness, damping between the pile and surrounding soil and the additional mass of soil which contributes with pile in dynamic performance applying harmonic vibration would be presented
With using of experimental results which was done by first author, static and dynamic stiffness were calculated in two methods that are explained in later section
Summary
The purpose of this study is to study on the static and dynamic properties of buried pipeline and surrounded soil in axial direction due to harmonic dynamic vibration. The stiffness between soil and pipe in different static and dynamic conditions and cases based on the dynamic distributed formulation, considering soil additional mass share and refer to numerical experimental results, has been estimated and concluded in the following pages.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have