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## RECTANGULAR SPREAD FOOTING ANALYSIS This location is for Registered Users Only.Perhaps you need to login or register.

Description:
Calculation Preview

This program is a workbook consisting of five (5) worksheets, described as follows:
Footings (Table) - Multiple rectangular spread footings analysis and design (table format)
Footings (Pier Table) - Multiple rectangular spread footings - pier analysis (table format)

Program Assumptions and Limitations:

1.This program assumes that the spread footing is in fact "rigid", so that the bearing pressure is distributed linearly on a homogeneous soil.(Note: the actual footing is generally not "rigid", nor is the pressure beaneth it distributed linearly.However, it has been found that solutions using the assumed "rigid" concept are adequate and generally result in a conservative design.)

"Analytical Approach to Biaxial Eccentricity" - by Eli Czerniak
Journal of the Structural Division, Proceedings of the ASCE, ST4 (1962), ST3 (1963)

"Bearing Pressures for Rectangular Footings with Biaxial Uplift" - by Kenneth E. Wilson
Journal of Bridge Engineering -Feb. 1997

input in each of the two table format worksheets.

Calculation Reference
Footings and Foundations

Submitted By:
Alex Tomanovich (ATomanovich)
Submitted On:
03 Apr 2014
File Size:
2,421.00 Kb
1984
File Version:
3.7
File Author:
Alex Tomanovich
Rating:
ATomanovich 2 years ago

It is a simple iterative solution that a friend and myself developed many years ago for the HP41CX programmable calculators based on an article and procedure written by Eli Czerniak. It might be best if you merely "borrow" the procedure in my spreadsheet and embed it into your own. I do not mind. It's involved and a bit convoluted to explain in words. However, the main thing is that it works.
If you want to [url=/contact/alex-tomanovich/]email me[/url], I'll be glad to send you a PDF copy of that Czerniak article.

Alex
AMMamore 2 years ago
Alex,
First of all I do appreciate all your spreadsheets. One subscriber mentioned about bi-axial bending. I am just curious how, or what method did you use? Earlier, we used a graph and find some factors to do the bi-axial bending. How did you do that in an spreadsheet, without those graphs? Can you help me out on this one?

The reason I ask is that I have been trying to make my own spreadsheet to do an isolated footing but I could only do it for uni-axial bending. The object of my spreadsheet is not only to solve for the soil pressures, but also to do the concrete and reinforcement designs. And I'd like to share it with everyone, but not yet, because of its limitation with regards to biaxial bending. Thanks.
ATomanovich 3 years ago

Jirair,

I'm not sure why you are having issues with using my FOOTINGS.xls spreadsheet workbook. I make use of input data validation comments as well as other general comments (denoted by red triangles) to hopefully clarify the user input or explain any restrictions or limitations in the input.

All of the spreadsheets that I write make use of comments to varying degrees, and I've never had any complaints from anyone else before about them.

The worksheets are protected, but not with a password. However, unprotecting them will not make the comments go away, but you can blow them away in your own personal copies if you choose.

That's about all I can offer you on this subject.

Regards,

Alex
jirairs 3 years ago
Cannot use it with all the comments attached to each box.

Regards,
Jirair
VR2007 4 years ago
Great set of calculations! You're really good in what you do.
ATomanovich 5 years ago
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.
Thanks
ATomanovich 6 years ago
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.
This workbook is now version 3.6.
slasher47 6 years ago
wow!! ive created this account just to say "wow! Thank you for this spread sheet!"

ive been searching the internet and this is the only spread sheet that can demonstrate / calculate bi-axial loading (theoretically).

believe me, this is the question every beginner always ask to themselves. and in the end of searching, its good to know there is one who dares, who "knows", not selfish and humble enough to share this knowledge to everyone (beginner, pros, master)

not all can do this. thats why from now on, i a great fan hehehe

thank you sir! i appreciated you hard work :D
fergy 6 years ago
This is a very good sheet and easily usable.
thanks
ATomanovich 7 years ago
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.
coolkartal8310 7 years ago
tnhx
ATomanovich 8 years ago
Here's an update to 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.
crystalinv 8 years ago
this is great. thank u very much. keep up...
Is it realy good
morovati 8 years ago
thanks a lot
gentleman59 9 years ago
thx
gentleman59 9 years ago
thx
ATomanovich 9 years ago
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.
ATomanovich 9 years ago
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.
While I was at it, I made the following couple of additional changes which hopefully are useful improvements:
In the first 2 worksheets which analyze a single footing at a time, a summary of results was added just off of the main calculation page to the right. This allows the user to quickly check the results during the process of iterating the footing dimensions, etc. in the input data, without having to take the time to either scroll down or "split-screen" the display to view the results.
I grouped all of the separate drawing components which composed the individual sketches in the worksheets into individual grouped drawing objects. This will allow the user to unprotect the worksheet, select the drawing object as a whole, and re-position it in the worksheet to make room for any additional text comments/verbiage if desired.
boudira 9 years ago
thanks
boudira 9 years ago
thanks
conder 9 years ago
Thanks.
conder 9 years ago
Thanks.
ATomanovich 9 years ago
Along the same lines as the changes I made to the "RECTBEAM (318-05).xls" workbook, changes were made in the 2 table-type worksheets for actual footing design pertaining to the capacity reduction factor, "phi", for flexural tension.
In the "Footings (Table)" worksheet, the program still assumes "phi" = 0.90 for the sake of being able to calculate and suggest numbers of reinforcing bars and size of bars. I've added caution notes in the calculations as well as the "DOC" worksheet to alert the user. Most often in the design of footings the cross section will be "tension controlled", and thus the flexural tension "phi" factor will be = 0.90 anyway. This worksheet now calculates the strain in the tension reinforcing and then calculates the "phi" factor. The user can then review the results for the calculated "phi" factor to determine if it is in fact = 0.90 so that the determined reinforcing can be used. If the calculated "phi" factor is < 0.90, then the user will have to increase the footing thickness until the calculated value of "phi" = 0.90.
In the "Footings (Pier Table)" worksheet for the point on the interaction curve for pure moment (no axial load), the program now calculates the strain in the tension reinforcing, then calculates the "phi" factor, and finally calculates the ultimate moment capacity, (phi)Mn.
ATomanovich 10 years ago
I have a message in many, but not all, of my spreadsheets about clearing the contents of input cells not used, and NOT to use the Space Bar to do this. This is just a reminder to you all that just to be safe, always highlight the cells to be cleared, Right-Click the mouse, and then select "Clear Contents". Of course, in most of the programs where a numerical value is expected, inputting values of 0 will also work, but usually that takes more effort and often looks too busy.
Equiangular 10 years ago
Equiangular 10 years ago
j_vidals 10 years ago
Thank you for this excelent job
j_vidals 10 years ago
Thank you for this excelent job
MSH 10 years ago
After I used, benefited, and enjoyed your spreadsheets, finally I found the time to say,
MSH 10 years ago
After I used, benefited, and enjoyed your spreadsheets, finally I found the time to say,
shapoor57 10 years ago
Thanks.
shapoor57 10 years ago
Thanks.
ATomanovich 11 years ago
This workbook has some concrete design in them, based on the ACI 318-99 Code in their original form. To reflect the use of the ACI 318-05, I decided to give the user the option of selecting what ACI Code is desired to be used, 318-99, 318-02, or 318-05, in those specific worksheets. Once the user selects the desired ACI Code, the appropriate "phi" factors are displayed and used. One word of caution, be careful not to mix & match "phi" factors and load factors from the various concrete codes. It's obviously up to the user to be consistent. For the purpose of just what specific concrete analysis and design is done in this workbook, the selection of either ACI 318-02 or 318-05 gives the same results.
esfamatigan 11 years ago
Thank you for this work.
esfamatigan 11 years ago
Thank you for this work.

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