Program Description:
"CIRCBASE" is a spreadsheet program written in MS-Excel for the purpose of analysis of steel column base plates.  Specifically, pipe columns base plates may be subjected to axial loads (compression only), with or without column bending, plus shear.  Base plate bearing pressure is checked as well as bolt tension, if applicable.  If shear is present, bolt shear as well as interaction of bolt tension and shear, if applicable, are calculated.  Finally, a propoesed base plate thickness is is checked.
This program is a workbook consisting of two (2) worksheets, described as follows:
Doc - This documentation sheet
Complete method - Circular base plate analysis
Program Assumptions and Limitations:
1.   This program follows the procedures and guidelines of "Design of Monopole Bases", by Daniel Horn, P.E.
2.   This program follows the procedures and guidelines of the AISC 9th Edition Allowable Stress (ASD) Manual (2nd Revision, 1995) for round hollow structural tube & column base plates subjected to flexure.
3.   For steel interaction of anchor bolt tension and shear, this program follows:
      Appendix D of ACI 318-02, "Building Code Requirements For Structural Concrete"
4. For concrete bearing, this program follows:
      Section 10.17 of ACI 318-02, "Building Code Requirements For Structural Concrete"
5.   User has option to take out some of the total shear though friction between column base and grout based on column dead load and coefficient of friction, thus reducing amount of shear to be taken by anchor bolts.
6.   Additional assumptions used in this program are as follows:
          a.  The column is centered on a circular base plate in both directions.
          b.  The column & base plate are centered on a round pedestal in both directions.
          b.  Axial column load, 'P' > 0  for the case with moment.
7.  This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc.  (Note:  presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell.  Merely move the mouse pointer to the desired cell to view the contents of that particular "comment box".)
8.  For the addition of gusset plates to the baseplate, this program derives the baseplate moments from "Theory of Plates and Shells", by S. Tomonshenko. (1st Edition, 1940)
          a.  Table 26 - Deflection & Bending Moments for a Uniformly Loaded Plate with Two Opposite Edges
               Simply Supported, the Third Edge Free and the Fourth is Built In (Page 218)

Calculation Reference
AISC 9th Edition Allowable Stress (ASD) Manual
ACI 318-02 Building Code Requirements For Structural Concrete

Calculation Preview

29 Oct 2009
Last Modified
29 Oct 2009
File Size:
214.50 Kb
File Version:

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Comments: 12
rbgaines 5 years ago
Thanks very much to Mr. Doyle for getting me up and running with ExcelCalcs. . I greatly appreciate it!
This spreadsheet for a circular baseplate calculation is very helpful to me regarding a project I'm 'under the gun' for at present. If anyone has time to answer one clarification, I would appreciate it:
My past experience has been with calculating embedded light pole foundations (caisson type pier footings). The iterative process is similar to that employed with embedded foundations to determine the requisite footing depth below grade.
My question regarding the circular baseplate program is trying to determine if/where the program determines the requisite concrete thickness and minimum bolt embedment. Could someone clarify that for me? I'm wondering if qcalc is related to this?
I've been reading through the references provided, trying to tune-in on that area, but haven't had a lot of luck so far.
Romulan 9 years ago
A mod in the form of an auto solver (macro) has been introduced.
Saves a lot of guesswork
Jwinslow 10 years ago
I had started to develop a spreadsheet of my own based on Daniel Horn?s Tech Manual, and was having problems working out some bugs I was having with it. I found the Circbase spreadsheet here, and it has been a great help. This is a very well thought-out spreadsheet; the input and documentation is very clear. However, I do have a few of items I would like to have verified, if possible.
In the calculation for ?I1? in cell P44, the fourth term uses sin(yc/ri). Referencing page 57 of Horn?s Tech Manual, I believe this should be the arcsin.
The fourth term in the written equation in cell Q44 shows ?r^2*sin(yo/r)/4? I believe this should be r^4*asin(yo/r)/4 as used in cell P44 and Horn?s example on page 60.
The formula in cell P39 uses the value for A1. The last value in the written equation in cell Q39 uses Ac. Page 56 of Horn?s manual shows Ac, but the example on page 60 uses the value of A1. I believe A1 is the correct value to use.
The fourth term in the written equation in cell Q45 shows ?ri^2*sin(yc/ri)/4? I believe this should be ri^4*asin(yc/ri)/4 as used in cell P45 and Horn?s example on page 60. I believe a negative sign should also be shown before the first bracket.(These corrections are used in the formula in cell P45).
The first comment above is the only one that actually affects the results. Using the data from Horn's example, the maximum bolt force and concrete stress only changed by about 2%. But once I made the change from sin to asin, I was able to match results from this spreadsheet, the one I had been working on, and Horn?s example to within 4 decimal places.
Can anyone verify these adjustments?
Thanks for the spreadsheet and any comments.
JohnDoyle[Admin] 12 years ago
There is a clear warning that the maximum number of bolts is 24. However cou could modify the calculation. The worksheet is protected but no password is required to unprotect it. Then you can unhide columns J:AM to reaveal a 24 bolt calculation table in AB9:AI33. I am not so familiar with the details of the calculation but this seems to be a reasonable way forward for you.
design.mukesh 12 years ago
dear sir , i want to increase no. of bolts more than 24 , its 30. is it ok to change this.
JohnDoyle[Admin] 12 years ago
I have just changed the number of bolts in cell D35 from 6 to 10 and watched as the Safety Ratios (SR) increase.
design.mukesh 12 years ago
hi , i want to increase no. of bolts how its possible or what effect of it on calculation.
mdmichiels 14 years ago
mdmichiels 14 years ago
Thanks for the comment! The spreadsheet is looking at the compression bending stress of the baseplate that is occurring between the anchor bolts. This is assuming the number of gussets (if any are present) does not outnumber the anchor bolts. A quick internet search should reveal the source document, free for download. Hopefully this answers your question.
mdmichiels 14 years ago
Hi mdmichiels - I have just noticed a new comment on the download page. Is this some thing you can address?
pandavision 14 years ago
I think the effective width is calculated incorrectly... Ng, not Nb
mdmichiels 14 years ago
Very good calculation (a disciple of Alex Tomanavich I think). Please accept a free XLC Pro (12M) subscription with our gratitude.