andysines,
I favor using Figure 25.9-3 for a trussed tower. To use this correctly, the Cf is calculated using the solidity ratio on the windward face. The exposed area should be I think, the exposed area of the windard face. The coefficient in the Figure gives the total wind force on both...
Greg & dhengr, thank you for the references, I will check both of them out.
Electricpete, thanks also for that referral. I’ve got a copy of that, and looked at it carefully when considering concrete and geotechnical aspects of the foundation design. But I had skipped over the parts about the...
Greg,
No, I haven’t read a book on the subject. I have looked in several books on vibration and on machine design. Also at a number of articles on rotating shafts, vibration of shafts, machine maintenance, etc. None of them deal with the subject at all completely. Just bits and pieces that...
...limit and the operating speed), its location along the length of the shaft, and the horizontal couple, which is defined by an eccentricity in g*mm and a length distance.
The balancing process itself I don’t understand. It does seem that the goal in balancing is to make this eccentricity...
I am developing a spreadsheet for analysis/design of foundations for vibrating and rotating equipment. This post is about input for that design, specifically the eccentricity
of the rotor(s) in a turbine generator. It also should be applicable to other types of rotors as well. I am...
lexcognito,
Note: in your original worksheet, you had A.i rather than A[i, hence the error as the range variable should (usually) appear on the left hand side of a definition if it's on the right hand side.
Wow! How did you figure that out??! Onscreen, those two look the same to me...
Rfreund,
1) I would only figure the exposed area based on the windward face members and not consider any of the "unshielded" members on the leeward face.
2) Your point about applying wind to the leeward face of a structure comprised of 2 lattice frames is conceptually correct. However...
bjb
The following quote from the indicated publication answers your question about Fig. 6.23 in ASCE 7-05. THis is from the guide to the wind load provisions in ASCE 7-02, but the table in ASCE 7-05 is the same.
Guide to the Use uf the WindLoad ?ruvisions of ASCE7-O2
Kishor C. Mehta...
biendung1304,
You definitely need more information about the crusher. I doubt you will find the needed information in any text or handbook.
You will need things like the dynamic loads applied, including direction, frequency, ampltude and point of application. Also the cg location...
SEgeek4,
Below are two links to a book published by ASCE that goes into great detail on that subject. I have access to it on a company paid subscription service, so I didn't have to buy it myself. But I found it a good reference...
...(1-(f/fc)^2). ebar = static eccentricity, f = operating frequency fc = critical frequency for the rotar.
Further, dynamic force applied = Wr/g*e*omega^2. So then, the eccentricity varies with frequency and the applied force varies (further) weith the operating frequency. (see this in the...
adfo,
An angineer by the name of Alex Tomanovich produces many excellent spreadsheets for structural calculations. Many are available at the AISC website SteelTools.
http://www.steeltools.org/Home/
There is a recent posting there for one of Alex's spreadsheets that covers IBC 2009...
All,
Please see the attached xlsx file.
I've calculated the wind loads for a site in midwestern USA, for all four Occupancy Categories, and compared final pressures in psf for both ASD and LRFD...
ieronimoyuri,
Here is a link to a webpage:
http://www.wbdg.org/ccb/DHS/fema451.pdf
Try this website for a pdf file of the fiollowing publication:
NEHRP Recommended Provisions: Design Examples FEMA 451 - August 2006.
This is a fairly comprehensive set of examples for applying the...
SWmechE,
This is off-topic, but whenever I want to read a table such as the AISC database, I simply import it from a spreadsheet into a data table right in my Mathcad worksheet. Then use vlookup functions to get data out of that. I do not want to have to manage a bunch of other spreadsheet...
Corey,
The E in that equation was deleted in the errata Posted on May 3, 2007.
Look for the errata on the following website:
http://www.seinstitute.org/pdf/erratasheet7-05.pdf
regards,
chichuck
