Civil MDC



“PILEGRP” Program

Program Description:
“PILEGRP” is a spreadsheet program written in MS-Excel for the purpose of analysis of pile groups with rigid
caps using the “elastic method”.  Specifically, the properties of the pile group are calculated, and then based
upon the applied vertical and horizontal loadings, the vertical and horizontal pile reactions are calculated.
There is also a worksheet to check beam and punching shear in the pile cap for a single corner pile, for the 
purpose of estimating the required pile cap thickness and subsequent pile cap weight.
This program is a workbook consisting of ten (10) worksheets, described as follows:
Worksheet Name
Piles (<=25) 
Piles (<=25)(metric) 
Piles (<=75) 
Piles (<=75)(metric) 
Piles (<=300) 
Piles (<=300)(metric)
Piles (<=400) 
Piles (<=400)(metric)
Corner Pile Shear
Program Assumptions and Limitations:
1.  The Pile Group worksheets assume a minimum of 2 piles and a maximum of either 25, 75, 300, or 400 piles 
     for a pile group.
2.  This program uses the “elastic method” of analysis, assuming that the pile cap is in fact “rigid”, so that the
     applied loads are linearly distributed among the piles.  A common “rule-of-thumb” is to assume a pile cap 
     thickness equal to least 1/10 of the longest dimension (length or width) of the pile cap.  All piles are assumed 
     to be vertical, and of equal size and length (stiffness).  Battered piles are NOT permitted.  The tops of all piles 
     are assumed at the same level. 
3.  This program assumes an orthogonal X-Y-Z coordinate system.  All piles and piers MUST BE located in the
     “positive” (1st) quadrant.  “Negative” pile or pier/loading location coordinates are NOT permitted.
     “Right-Hand-Rule” sign convention is used for all applied forces and moments at pier locations.
4.  The piles and piers/loadings can be numbered in any desired order.  However, the user should make 
     sure to either clear the contents of all spreadsheet cells that are not used for input or those cell values should
     be input = 0.  All piles and piers/loadings MUST BE input in proper numerical sequence with no “breaks” in
     the numerical order of input data.
5.  This program does NOT include the weight of the pile cap or piers in the calculation of the vertical pile reactions.
     However, the total weight of the pile cap and piers may be included by assuming an additional “ficticious” pier
     located at the centroid of the pile cap plan area, and applying the total weight at that “pier” location.
6.  This program does NOT check the actual calculated pile reactions (vertical and horizontal) against known
     or given allowable pile reactions for downward, uplift, or lateral cases.  This is done so that the extent of any 
     acceptable overstress is left up to the judgement of the user.  However, in all cases this must be checked by
     the user.
7.  This program does NOT check the shear (beam-type or punching) nor the flexural requirements of the pile cap.
     This must be done independently by the user.
8.  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”.)

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