Comprehensive Spreadsheet for Pole Foundation Analysis

POLEFDN” refers to a MS excel based spreadsheet program that can be used to analyze a pole foundation presuming the application of a firm round pier that is taken free (unrestrained) at the top and susceptible to lateral and vertical loads.

In particular, the sheet makes the calculation of necessary embedment depth, the maximum moment and shear, the plain concrete stresses, and the soil bearing pressures. This program is a workbook that comprises of six (6) worksheets, details of which are given below:

Doc – Documentation sheet
Pole Fdn (Czerniak) – Pole foundation analysis for free-top round piers with PCA/Czerniak method
Pole Fdn (UBC-IBC) – Pole foundation analysis for free-top round piers with UBC/IBC method
Pole Fdn (OAAA) – Pole foundation analysis for free-top round piers with OAAA method
Granular Soil (Teng) – Pole foundation analysis in granular soil with USS/Teng method
Cohesive Soil (Teng) – Pole foundation analysis in cohesive soil with USS/Teng method

Program Assumptions and constraints:

1. As there is not a recognized method for pole foundation analysis, this program is available with five (5) different methods of finding out embedment length for pole foundations. The “Pole Fdn(Czerniak)” worksheet is the principal method highlighted in this program, because it offers the most detail in overall analysis. However, it provides the most conventional embedment depth results of all the methods illustrated.

2. The references applied in various analysis methods in this program are given below :

a. ”Design of Concrete Foundation Piers” – by Frank Randall Portland Cement Association (PCA) – Skokie, IL, May 1968
b. ”Resistance to Overturning of Single, Short Piles” – by Eli Czerniak ASCE Journal of the Structural Division, Vol. 83, No. ST2, Paper 1188, March 1957
c. 1997 Uniform Building Code (UBC), Section 1806.8, page 2-45
d. Outdoor Advertising Association of America (OAAA) – New York, NY
e. ”Tapered Steel Poles – Caisson Foundation Design” specifically created for United States Steel Corporation by Teng and Associates, July 1969
f. AASHTO Publication LTS-5 – Standard Specifications for providing structural Supports to Highway Signs, Luminaries, and Traffic Signals (Fifth Edition, 2009)

Also Read: How to design bridges through excel sheets

Note: references “a” and “b” belong to the “Pole Fdn(Czerniak)” worksheet, whereas references “e” and “f” belong to both the “Granular Soil(Teng)” and “Cohesive Soil(Teng)” worksheets.

3. The “Pole Fdn(Czerniak)” worksheet presumes that the foundation is short, rigid, satisfying the criteria that the foundation embedment length divided with the foundation diameter.

4. This program will deal with both horizontally and vertically enforced loads. The vertical load may contain an associated eccentricity that leads to a supplementary overturning moment that is always presumed to add directly to the overturning moment created with the horizontal load.

5. This program presumes that the top of the pier remains at or over the top of the ground surface level.

6. This program presumes that the actual resisting surface presents at or underneath the ground surface level. It takes into account any weak soil or any soil that is detached at the top.

7. The “Pole Fdn(Czerniak)” worksheet presumes that the rigid pier rotates about a point located at a distance, ‘a’, under resisting the surface. The maximum shear in pier is considered as ‘a’ distance, while the maximum moment in the pier is taken at a distance = ‘a/2′.

8. The “Pole Fdn(Czerniak)” worksheet computes the “plain” (unreinforced) concrete stresses, compression, tension, and shear in the pier. The respective allowable stresses are also determined based on the strength (f’c) of the concrete. This is done to determine if steel reinforcing is actually required. However, whether minimum reinforcing should be utilized or not, is decided the users. The permissible tension stress in “plain” concrete is presumed to be identical to 10% of the value of the permissible compressive stress.

To download the software, click on the following link drive.google.com

9. The “Pole Fdn(Czerniak)” worksheet works out the actual soil bearing pressures across the side of the pier at distances equal to ‘a/2′ and ‘L’. The related permissible passive pressures at those locations are ascertained for comparison. However, it is dependent on the user to find out the suitabiity.

10. As all overturning loads are safeguarded by the passive pressure against the embedment of the pier, this program presumes that the pier functions in direct end bearing to defy only the vertical loading. The bottom of pier bearing pressure is computed, that comprises of the self-weight of the pier, assumed at 0.150 kcf for the concrete.