Natural vibration period of the pipeline
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How should the natural vibration period be selected for the seismic design of overhead pipelines? Can it only be calculated using software? Has anyone calculated a value for reference?
Are you planning to select the acceleration according to sh3039? There’s a problem with the graphics on sh3039. Take a look at this post at http://www.pipingsoft.com/bbs/thread-4871-1-2.html!
Reply to 2# llu85: Of course, I referred to 3039 as a reference, but later I saw that the formula in 50011 was different, so I stopped looking at 3039 and instead used 50011 as a guide for programming. However, the value for the pipe’s natural vibration period T wasn’t specified there; I found in some sources that it ranges from 0.1 to 0.3, so I had no choice but to use that range. Only by using software can one determine the pipe’s natural vibration period, so it’s better to use software for seismic analysis
Actually, a maximum value can be taken. This is the most conservative approach!
This post was last edited by gaoshun on 2011-8-4 at 12:49. Reply to 3# superkiller0305: My understanding is that determining the natural vibration period means finding the natural frequency of the piping system, but it’s difficult to determine this frequency; generally, software is required to carry out such calculations. For simplicity in calculations, only empirical data can be used. The value 3039 was chosen in order to apply equivalent static forces; if, after all that effort, dynamic analysis is still necessary, then it’s better to carry out a dynamic analysis directly. I also have a question: when using 3039, it is necessary to know the shear wave velocity and the thickness of the overburden layer. I’m curious as to how everyone determines these values
Reply: It’s explained on page 4 of 5# gaoshun hg/t 3039
This post was last edited by gaoshun on 2011-8-6 at 13:27. Reply to 6# superkiller0305: My understanding is that to determine the characteristic period in 3039, it is necessary to know the site category, and the determination of the site category requires the shear wave speed and the thickness of the overburden layer. How can these two parameters be determined? Party A sometimes does not provide such parameters. Are there other ways to determine it? Please give your advice