ASME STS-1-2000 question

[warrenw]

I just recently received the new Steel Stacks Standard STS-1-2000. I have been reviewing the example "E-3" "Along Wind Loads" on page 79-81. I have found places where I can't understand the answers that are shown; as an example on page 80 -- Total Damping B = Bs + Ba. On page 79 Bs = 0.004, on page 80 ba = 0.00869. So why does Bs + Ba = 0.00816 ?? shouldn't it be 0.01269 ?
Also on page 80 directly to the right of Total Damping is a calculation for "R" which is shown to equal 0.38 , I can not come up with this number. If I use their value for B = 0.00816, I get "R" = 0.578.
Lastly, I can't come up with the "base moment fluctuaing component" MbarD = 759.0 ft-kips.
Can any of you shed some light on this ?I would appreciate any help here.

 

[warrenw]

No respones, I'm disapointed. I was hoping this forum could be of some help to me and others. Is the question too difficult , am I being too impatient for an answer, or is it because I'm only a visitor?

 

[whymrg]

I do not think anyone using Steel Stacks Standard STS-1-2000

 

[meca]

WarrenW: I have just received my copy of STS-2000 as well and have been working to incorporate this new code into my stack programs (

http://www.mecaconsulting.com).

I find the Vortex Induced Response section to be quite confusing. I can not shed any light on your questions (Beta and R), because I believe that these must be errors. In addition, I think that there are a couple of other errors in Example E-3.

1) VR = V * (I)^0.5 per Section 5.5, but in the equation on pg 79 for Vbar zbar it seems that they use V instead of Vr.

2) Zbar should be 5/6 * Stack Ht (Sec. 5.2.2a), but on page 79 they use 0.6 * Stack Ht.

I am going to send an email summarizing these items to the secretary for the STS Committee. Hopefully he can shed some light or perhaps get these corrected in the future. If you send me me your email address I will forward his response.

Thanks,

Chris

http://www.mecaconsulting.com

chris@mecaconsulting.com

 

[meca]

Please disregard my comment # 1, I made an error.

 

[warrenw]

Chris; Thanks for the response. I'm glad to see that I'm not doing something wrong. This revision to the Standard was 8 years in coming and shows a Structural Design Subcommittee of 24 members and the first example I tried to follow is full of errors. I haven't even looked at the Seimic or Vortex Shedding examples. I did see some calculus formulas in the variable diameter section which makes me alittle uncomfortable because I have been trying to avoid calculus since college 25 years ago. I hope you get a quick and understandable answer from the STS Committee.
Warren.

 

[warrenw]

Chris; referring to your comment #2 - 5/6*H I think is the elevation (Zcr) of the mean hourly wind speed (see definitions on page 25) and 0.6*H is the equivalent height of stack (Zbar) as referenced in ASCE 7-98 section 6.5.8.1 (page 29) and table 6-4 (page 59). This is how I read it, but the standard is not clear.

 

[meca]

FYI...I have set up a web page dedicated to summarizing the differences between ASME STS-1-2000 and ASME STS-1-1992. If you would like to review or have anything to contribute, here is the link.

http://www.mecaconsulting.com/ASME STS 2000.htm