09-15-2009 13:27

Rectangular Spread Footing Analysis/Design. Capabilities include analysis of rigid footings/mats with up to 16 piers (load points), as well as the handling of uniaxial/biaxial eccentricities.

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03-27-2014 13:38

I have added a new worksheet to the "FOOTINGS.xls" spreadsheet workbook. This new worksheet deals with octagonally shaped rigid spread footings, and will perform the bearing pressure analysis, as well as stability checks for both overturning and sliding. With octagonally shaped spread footings being commonly used for the support of round vertical tanks, vessels, and stacks, I felt that this was a worthwhile addition to the workbook. The required coefficients used in the analysis are automatically extracted and interpolated from the Process Industry Practices (PIP) Document STE03350, "Vertical Vessel Foundation Design Guide" (2007).
Also, in the "Unsymmetrical Footing Base" worksheet, I added/expanded the comment boxes pertaining to the original general stress equation used to better clarify the equation's use and how the sign convention used in the worksheet relates to the original equation.
Finally, in all of the worksheets where a plan view plot of the footing is created, I revised the procedure for obtaining/maintaining a more correct aspect ratio for the plot. Off of the calculation page and to the upper right, the user now inputs a value which is termed as "Axes Lengths Ratio"......the ratio of the actual on-screen measured lengths of the X and Y axes. This should keep the plots looking more to correct scale than they have in many cases in the past.
The current version of this workbook is now version 3.7.

05-01-2013 09:30

Regarding the 2013 update to Version 3.6, the author states:
In the "Footings (Table)" worksheet of the "FOOTINGS.xls", it was discovered that original intended criteria for use of top reinforcing was not being handled for all cases. I had originally set the criteria for the use of top reinforcing in the footing base to be for either the case with uplift load on the footing pier and/or for the case when there is no soil cover (D = 0) over the top of the footing. The worksheet was providing top reinforcing when an uplift load was input. However, for the special case of no uplift load along with no soil cover, the worksheet was showing the top reinforcing = 0, when there should have been a calculated value > 0.
I have made the necessary corrections.

12-25-2012 23:43

Amazing spreadsheet. Thanks for sharing. I have seen, and developed several footing worksheets but none of it is as practically useful as this one.

05-08-2012 13:06

While in and using the "FOOTINGS.xls" workbook recently, I discovered that there were several comment boxes that at some point have gotten shrunk down to where all of the text was not visible. I went through the entire workbook and made the adjustments to the sizes of the comment boxes where required.
While I was at it, I decided to update both the "Footings (Table)" and "Footings (Pier Table)" worksheets to be applicable for ACI 318 Codes, now up through the ACI 318-11 Code version. As best that I could tell, there have been no real changes to the ACI 318 Code (methodology, phi factors, etc.) , at least as far as flexure, shear, compression, and bearing are concerned, since the 2002 version. So it was a relatively easy modification to get those two worksheets updated.
This workbook is now version 3.5.

04-18-2011 12:27

I've updated the "FOOTINGS.xls" workbook which now includes 2 new worksheets, one for a rigid footing analysis with up to 16 piers/load points, and the other to analyze a rigid, unsymmetrical footing base. The names of the 2 new worksheet tabs are "Footing (16 net pier loads)" and "Unsymmetrical Footing Base".
The "Footing (16 net pier loads)" worksheet should help particularly with bearing pressure and stability analysis for equipment foundations involving several piers/pedestals and short walls all on a common rigid foundation. The "Unsymmetrical Footing Base" worksheet should help with analysis of maximum soil pressure for situations where a non-rectangular shaped rigid footing base has to be used.
The current version is now 3.4.

01-28-2010 09:56

In the "Footings (Pier Table)" worksheet of the "FOOTINGS.xls" spreadsheet workbook (version 3.2), I ran across another "#REF" error (illegal cell reference). This was in the program logic in Column CV28. This error ONLY showed up for a design eccentricity, ey =Mux*12/Pu, which fell between Points #9 (pure moment) and #10 (pure axial tension) on the interaction curve. Like the previous update, this error was inadvertently created during the editing process in adding the calculations for determining the "phi factor" for flexural tension originating in version 3.1. I thought I had caught and covered all of this in the previous version 3.2 update, but unfortunately I missed this one.

I have corrected this, and the updated workbook is now version 3.3.

11-17-2009 07:45

In the "Footings (Pier Table)" worksheet of the "FOOTINGS.xls" spreadsheet workbook, a "#REF" error (illegal cell reference) was discovered in the program logic in Column CT28. This error only showed up for a design eccentricity, ey =Mux*12/Pu, which fell between Points #8 and #9 on the interaction curve. This error was not in version 3.0 of this workbook, and I must have inadvertently created as part of the editing process in adding the calculations for determining the "phi factor" for flexural tension in version 3.1.

I have corrected this, and the updated workbook is now version 3.2.