Input parameters pane specifies the dimensions, properties of the pile, pile group and soil. These are entered in their respective tabs. If field pile load test data is available, it can be entered in the ‘field test data’ tab.
Pile Dimensions tab defines the pile type, crosssection of the pile and the dimensions of the pile for the foundation. It also displays a pictorial view of the pile along with the layers of soil.
Select the pile type (method of construction) used for the project in the pile dimensions tab. The choices for pile types are
a) Driven
b) Bored (Bored castinsitu)
c) CFA (Continuous flight auger)
d) Driven Castinsitu
The method of construction along with the pile crosssection and pile material is used to determine the default values for 'k earth pressure coefficient' for sand layers.
The table below describes the practical choices for pile method of construction, pile crosssection and material used. The application may give warnings (which may be ignored by the user) if the selections don’t adhere to the table below.
Table 1 Pile type, crosssection, material compatibility matrix
Pile Type 
Driven 
Bored 
CFA 
Driven Castinsitu 

Pile Crosssection 
Hollow Circular HSection 
Square Rectangular Hollow Circular 
Full Circular 
Full Circular 
Full Circular 
Construction material 
Steel 
Concrete 
Concrete 
Concrete 
Concrete 
Select the pile crosssection to be used for the project in the pile dimensions tab. The choices for pile crosssection are
a) Full circular pile
b) Square pile
c) Rectangular pile
d) Hollow circular pile
e) H Section pile
Based on the crosssection of the pile, define the parameters of the pile in the adjacent pile dimensions pane.
The application may give warnings (which may be ignored by user) if the selections don’t adhere to the Table 1Pile type, crosssection, material compatibility matrix described in 'Pile Type' section.
Table 2 Summary of parameters to be specified for the different pile cross sections.

Full Circular pile 
Square pile 
Rectangular pile 
Hollow Circular pile 
H Section pile 
Pile length 
✓ 
✓ 
✓ 
✓ 
✓ 
Pile length above ground 
Optional 
Optional 
Optional 
Optional 
Optional 
Number of elements 
✓ 
✓ 
✓ 
✓ 
✓ 
Pile diameter 
✓ 


✓ 

Diameter of base 
Optional 




Pile wall thickness 



✓ 

Sectional breadth 

✓ 
✓ 

✓ 
Sectional depth 


✓ 

✓ 
Sectional area 




✓ 
Moment of inertia about xaxis 




✓ 
Moment of inertia about yaxis 




✓ 
Specify the pile length here in the units chosen. After selecting the pile crosssection, this should be the first item to be entered on this page. This field is mandatory for all pile crosssections.
Note: For TRIAL version, Pile length is restricted to 6m (19.6ft)
Specify the length of the pile length above the ground here in the units chosen. This field is optional and applicable for all pile crosssections.
This is the guidance of number of elements used in the finite element calculation. The program may adjust this number based on the other input data to carry out the analysis. A higher number of elements will improve granularity but may result in some loss of fidelity. The default value of 50 elements is recommended.
Use the slider to select the number of elements. A minimum of 20 elements and a maximum of 100 elements are permitted. This field is applicable for all pile crosssections.
Specify the external diameter of the pile here in the units specified. This field is mandatory for Full circular pile and Hollow Circular Pile.
Specify the diameter of base of the pile here in the units specified if different from the pile diameter. This is usually required for piles with enlarged bases. This field is optional and can be specified only for full circular pile.
Specify the pile wall thickness of the pile in the units specified. This field is mandatory and applicable for hollow circular pile.
Specify the sectional breadth the pile here in the units specified. This field is mandatory for Square pile, Rectangular pile and H Section pile.
Specify the sectional depth the pile here in the units specified. This field is mandatory for Rectangular pile and H Section Pile.
Square Pile 
Rectangular Pile 
H Section Pile 
Specify the sectional area the pile here in the units specified. This field is mandatory for H Section pile. The default value displayed here is calculated for a Hsection pile with a 1” thickness.
Specify the moment of inertia of the pile about Xaxis here in the units specified. This field is mandatory for H Section Pile.
Specify the moment of inertia of the pile in Yaxis here in the units specified. This field is mandatory for H Section Pile.
The pile diagram displays the pile along with all the layers of soil. Different scales are used for the depth axis and horizontal axis. The pile length in the diagram is 20 m. This diagram shows the perspective view of the pile along with the different layers of soil, scour and depth of water table.
Pile properties tab is used for specifying the properties of the pile material and selfweight inputs.
Use the dropdown menu to select the material used for the pile. The elastic modulus of the pile along with the unit weight is updated based on the selection.
Table 3 Elastic modulus of pile
Pile Material 
Elastic Modulus 

(kN/m^{3}) 
(kips/ft^{3)} 

Steel 


ASTMA36 
2.0*10^{8} 
4.173 * 10^{6} 
Concrete 


M20 
3.0 * 10^{7} 
6.26 * 10^{5} 
M25 
3.1 * 10^{7} 
6.47 * 10^{5} 
M30 
3.3 * 10^{7} 
6.68 * 10^{5} 
M35 
3.4 * 10^{7} 
7.10 * 10^{5} 
M40 
3.5 * 10^{7} 
7.31 * 10^{5} 
M45 
3.6 * 10^{7} 
7.52 * 10^{5} 
M50 
3.7 * 10^{7} 
7.73 * 10^{5} 
Select the “User Defined” option to enter values for the elastic modulus and unit weight of the pile material.
The elastic modulus of pile is shown here based on the material specified. If “User Defined” material is selected, the elastic modulus of the pile can be edited and entered here.
The unit weight of pile material of pile is shown here based on the material specified. If “User Defined” material is selected, the ‘unit weight of material’ can be edited and entered here.
The selfweight properties could be taken into account for axial analysis of the pile. The values of selfweight are autocalculated based on the pile dimensions and soil properties or they could be userdefined.
The automatically calculated ‘Effective pile weight’ is shown here as default value. Effective pile weight accounts for the reduction in pile weight due to buoyancy effect of water. This will be used for ‘selfweight’ analysis if required. To enter a user defined value of ‘effective pile weight’, select the checkbox adjacent to this and enter the user defined value in the ‘text field’ next to it.
The automatically calculated plug weight is shown here. The automatic calculation is based on the different soil layers and the inner diameter of the bottom segment of the pile. This is only relevant for driven hollow piles. A 0.9 reduction factor is used in calculating the plug weight. This will be used for ‘selfweight’ analysis if required. To enter a user defined value of plugweight, select the checkbox adjacent to this and enter the user defined values in the ‘text field’ next to it.
The Pile Group Data tab is used to enter the data required for the 'Pile group settlement analysis'
Select the 'Pile Group Cap'. Choices include
· Rigid cap
· Flexible cap
Select the arrangement of the piles in the group. The two choices currently are
· Grid
· User Defined
If the 'Grid' option is selected, a new pane will be visible and require the user to fill the Grid Details. The 'Pile Placement in Group' Table will then be updated with the placement of the piles in the group.
If the 'User defined' option is selected, the user will need to update the 'Pile Placement in Group' with the details of each pile.
Enter the number of rows, columns, spacing between the rows and spacing between the columns to define the grid. Click on 'Generate grid' to generate the grid and to update the 'Pile Placement in Group' with the location of each pile in the grid.
Each time the user changes any entry the 'Grid Details' pane, the 'Generate grid' button should be clicked to update the ''Pile Placement in Group' table.
The 'Pile Placement in Group' table is used to define the placement of individual piles in the group.
Use the (+) and () buttons at the top of the table to add / delete rows to the 'Pile Placement in Group' table. This option is only visible for 'User defined' pile geometry.
[Organize] button can be used to sort the values by Pile xcoordinate and to clean up empty entries in the table. This option is only visible for 'User defined' pile geometry.
Up to 500 Piles can be part of the group.
Table:
Doubleclick on the table cells to edit the content of the cells.
The table consists of four or five columns: No., Pile designation, Pile xcoord, Pile ycoord, Pile head load.
‘No.’ column cannot be edited and displays the entry index.
Pile designation Column – Description to identify the pile in the group.
Pile xcoord – xcoordinate location of the pile. Should be >=0. This column can be edited if 'User defined' Pile Geometry is selected in the adjacent pane. If 'Grid' is selected in the adjacent 'Pile Geometry', this field is generated and cannot be edited.
Pile ycoord – ycoordinate location of the pile. Should be >=0. This column can be edited if 'User defined' Pile Geometry is selected in the adjacent pane. If 'Grid' is selected in the adjacent 'Pile Geometry', this field is generated and cannot be edited.
Pile head load – Enter the vertical load on the pile head for each pile in this column. This column is visible and editable only in the case of piles with 'Flexible cap' and where 'Different load on piles' is selected in the 'Pile Group Loading' pane below.
Right click on the table to bringup the context menu to insert / delete rows in the table, cut, copy, delete and paste contents into the table. It is also possible to copy the table from excel and paste the contents into this table. Ensure adequate number of empty rows are added to the table prior to pasting contents from an excel table.
Load on pile cap – Enter the load applied on the pile cap. By default, the load is applied at the centroid location of the piles.
To apply the load at a different point, indicate the shift in the loading point from the centroid by specifying the 'eccentricity in x direction' and the 'eccentricity in y direction'.
Same load on all piles – Enter the 'Pile head load' in the text field adjacent to this option. This load will be applied on the pile head of all the piles in the group.
Different load on all piles – Select this option to specify different loads on each pile. The loads for each of the piles need to be specified in the 'Pile head load' column of the 'Pile Placement in Group' table above.
The Pile group crosssection diagram displays the view of the pile group from the top.
The Pile Group Diagram displays the 3D cabinet view of the pile group showing. For Rigid cap, load on the pilecap is also displayed. For Flexiblecap, loads on each pile are displayed if the number of piles is less or equal to 5.
Data in the soil properties tab is used to compute the pile capacity, design load for the pile, design load pile head settlement and the base stiffness of the soil at the pile tip.
If limit state design approach is used (i.e., design load is set as 1), factored soil properties must be used in this tab.
If the load test results carried out on a single pile on site is available, the load test data can be used along with base soil properties. Refer the ‘Field test data’ section. The base soil properties are also entered in the field test data section.
Soil properties tab is used to enter the details of soil layers, and standard penetration test (SPT) data. The tab is further subdivided into 2 tabs (on right hand side)
· SPT
Soil Properties Tab is used to enter the data about the site condition, subsoil layers and properties of each soil layer. It is divided into 3 panes
This field is not mandatory. Specify the local scour around the pile at the site. Enter the ‘scour’ value in the field.
Some restrictions on the scour depth:
· Scour depth can extend up to the first three layers of soil
· Scour depth should be less than 2.5 times of diameter of the pile
· Scour cannot extend into a rock layer.
This field is not mandatory. Specify the depth of water table at the site in the field provided.
If no value is specified, it is assumed the water table lies below all the layers of soil specified. For water table at ground level, set it as 0.
Specify the value of ‘Critical depth ratio’ (z_{c}/d) in the field provided.
Zc is the ratio of depth to diameter of pile beyond which the vertical and lateral effective stresses are considered to remain constant up to the pile base. The usual values are Zc = 15 for loose sand and 20 for dense sand.
Critical depth ratio’ is required for Pile capacity estimation in ‘Sand soil’ when the limiting side friction and base resistance are determined by the values computed at the critical depth. This method is followed in IS2911. The software also adopts this method for limiting base resistance determined by ‘Nq  Berezantev – Zc’ method. The table below summarizes the scenarios under which Zc is required.
Table 4 Scenarios where ‘critical depth ratio’ is required

Method for maximum base resistance 

N_{q}  q_{lim} method (API2011, API2000) 
N_{q}Z_{c} method (IS2911) 
N_{q} Berezantev  Z_{c} method 
Meyerhoff SPT method (IS2911) 
Meyerhoff SPT method for silty sand (IS2911) 

Method for maximum side friction 
β method (API2011) 

✓ 
✓ 


K  δ method (API2000) 

✓ 
✓ 



K  δ  Z_{c} method (IS2911) 
✓ 
✓ 
✓ 
✓ 
✓ 

Meyerhoff SPT method (IS2911) 

✓ 
✓ 



Meyerhoff SPT method for silty sand (IS2911) 

✓ 
✓ 


Min value: 15
Max value: 20
Default value: 15
Specify the unit weight of water in the field provided. This parameter is a mandatory field.
Min value: 9.5 kN/m^{3} or 0.062 kips/ft^{3}
Max value: 10.5 kN/m^{3} or 0.067 kips/ft^{3}
Default value: 9.8 kN/m^{3} or 0.063 kips/ft^{3}
The ‘Soil Layer Table’ is used to define the type of soil and the thickness of each layer of soil. The properties of the soil layer selected is entered in the adjacent ‘Soil Layer Properties’ pane.
Number of soil layers
First select the number of soil layers using the up/down arrow. This will set the number of rows in the table to populate
Up 50 soil layers can be specified.
Note: For TRIAL version, number of soil layers is restricted to 3.
Table: Doubleclick on the table cells to edit the content of the cells.
The table consists of four columns – Layer, Soil type, Starting depth and Layer thickness. The ‘Layer’ column and the ‘Starting depth’ columns cannot be edited.
To enter the Soil type, click on the cell in this column and select the type of soil from the ‘drop down’ menu for each segment.
Permissible soil types currently are – Soft Clay, Stiff Clay, Sand, Weak Rock and Hard Rock.
You can use ‘Sand’ to represent silt, silty sand and gravel as well.
Layer thickness Column – This defines the thickness of each layer of soil.
Starting depth Column – This column is auto calculated based on the thickness of soil layers entered.
The pile diagram in the pile dimensions tab will graphically show the values entered in this table.
Note: Soil layers should extend up to pile depth below ground + n * effective diameter
n = 3 for pile terminating in soil
n = 1 for pile terminating in rock.
Select a layer in the ‘Soil layer table’ to display the soil properties associated with it in this pane.
Note: Mandatory fields have a () adjacent to them.
Note: The soil layer properties need to be arrived at from the soil investigation report. The application populates median recommended values for each property. These values need to be updated with actual values from the soil investigation report or values chosen by the user.
Soil type: Shows the type of soil in this layer. (Field cannot be edited)
Unit weight of soil (γ): The unit weight to be given as data is the total unit weight of soil in the layer that is the moist unit weight above the water table and saturated unit weight below the water table. If required one may choose to divide the layer in to two halves one above water table and the other below the water table having different unit weights.
Starting depth: Displays the starting depth of the layer. (Field cannot be edited)
Layer thickness: Displays the thickness of the selected layer. (Field cannot be edited)
Method for maximum side friction: The table below details the options available for Soft Clay and Stiff Clay soil.
Table 5 Details of ‘Method for maximum side friction’ for clay soil
Method for maximum side friction 
Notes 
API2011 
(API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
a method (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
Semple & Ridgen (1984) 
(Semple and Rigden 1984) 
Kolk & Van Der Velde (1996) 
(Kolk and van der Velde 1996) 
The maximum unit shaft friction of clay soil layers is based on the equation
Where α is a multiplier and is the undrained cohesion of the soil. Methods of estimating the α multiplier by the following four methods are available in the software:
1) API RP GEO 2011
In this
2) α method (IS 2911)
Curve relating the given in the Standard is made use of.
3) Semple & Rigden (1984)
4) Kolk& van der Velde (1996)
The unit base resistance is given by
Method for maximum side friction: Select the method for maximum side friction from the dropdown list. This parameter is mandatory for Pile group settlement analysis.
Table 6 Details of ‘Method for maximum side friction’ for soft clay soil
Method for maximum side friction 
Notes 
API2011 
(API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
a method (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
Semple & Ridgen (1984) 
(Semple and Rigden 1984) 
Kolk & Van Der Velde (1996) 
(Kolk and van der Velde 1996) 
For more details on the methods, refer to the section on 'Method for maximum side friction' under 'Clay Soil'.
Table 7 Required properties for ‘Pile group settlement analysis’ for soft clay soil with respect to 'Method for maximum side friction'
Method for maximum side friction 
Cohesion at top 
Cohesion at bottom 
API2011 
✓ 
✓ 
α method (IS2911) 
✓ 
✓ 
Semple Rigden 
✓ 
✓ 
Kolk & Van der Velde 
✓ 
✓ 
Axial analysis method: Select the ‘Axial analysis method’ using the ‘drop down menu’ for axial load analysis.
Table 8 Axial analysis method details for Soft Clay
Axial analysis method 
Method details 
API2000 
(API 2000 RP2AWSD 2000) 
API2011 
(API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
Elastic method 
Based on elastic properties of soil. 
Table 9 Required properties for ‘Pile group settlement analysis’ for soft clay soil with respect to 'Axial analysis method'
Axial analysis method 
Cohesion at top 
Cohesion at bottom 
R factor 
Elastic modulus 
Poisson ratio 
API2011 
✓ 
✓ 
✓ 

API2000 
✓ 
✓ 
✓ 

Elastic Code 
✓ 
✓ 
✓ 
✓ 
Table 10 Soil property details for soft clay soil
Soil property 
Units 
Min value 
Max value 
Notes 
Elastic modulus of soil 
kN/m^{2} 
1750 
5000 

kips/ft^{2} 
36.54 
104.4 

Poisson Ratio 

0.1 
0.5 
Default value: 0.5 
Cohesion at top 
kN/m^{2} 
0 
100 
Value of 0 is only permissible for the first soil layer. 
kips/ft^{2} 
0 
2.09 

Cohesion at bottom 
kN/m^{2} 
> 0 
100 

kips/ft^{2} 
> 0 
2.09 

R factor 

0.5 
1.0 
Default value: 0.9 
Method for maximum side friction: Select the method for maximum side friction from the dropdown list. This parameter is mandatory.
Table 11 Details of ‘Method for maximum side friction’ for stiff clay soil
Method for maximum side friction 
Notes 
API2011 
(API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
a method (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
Semple & Ridgen (1984) 
(Semple and Rigden 1984) 
Kolk & Van Der Velde (1996) 
(Kolk and van der Velde 1996) 
For more details, refer to the section on 'Method for maximum side friction' under 'Clay Soil'.
Table 12 Required properties for ‘Pile group settlement analysis’ for stiff clay soil with respect to 'Method for maximum side friction'
Method for maximum side friction 
Cohesion at top 
Cohesion at bottom 
API2011 
✓ 
✓ 
α method (IS2911) 
✓ 
✓ 
Semple Rigden 
✓ 
✓ 
Kolk & Van der Velde 
✓ 
✓ 
Axial analysis method: Select the ‘Axial analysis method’ using the ‘drop down menu’ for axial load analysis.
Table 13 Axial analysis method details for stiff clay
Axial analysis method 
Method details 
API2000 
(API 2000 RP2AWSD 2000) 
API2011 
(API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
Elastic method 
Based on elastic properties of soil. 
Table 14 Required properties for ‘Pile group settlement analysis’ for stiff clay soil with respect to 'Axial analysis method'
Axial analysis method 
Cohesion at top 
Cohesion at bottom 
R factor 
Elastic modulus 
Poisson ratio 
API2011 
✓ 
✓ 
✓ 

API2000 
✓ 
✓ 
✓ 

Elastic Code 
✓ 
✓ 
✓ 
✓ 
Table 15 Soil property details for stiff clay soil
Soil property 
Units 
Min value 
Max value 
Notes 
Elastic modulus of soil 
kN/m^{2} 
4000 
10000 

kips/ft^{2} 
83.5 
208.8 

Poisson Ratio 

0.1 
0.5 
Recommended value Below water table: 0.5 Above water table: 0.4 
Cohesion at top 
kN/m^{2} 
100 

For the top layer, a value from 0 can be used. 
kips/ft^{2} 
2.09 


Cohesion at bottom 
kN/m^{2} 
100 


kips/ft^{2} 
2.09 


R factor 

0.5 
1.0 
Default value: 0.9 
Method for maximum side friction: Select the method for maximum side friction from the dropdown list. This parameter is mandatory for Pile group settlement. The table below details the options available for Sand soil.
Table 16 Details of ‘Method for maximum side friction’ for sand
Method for maximum side friction 
Notes 
β method (API2011) 
(API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
K  δ method (API2000) 
(API 2000 RP2AWSD 2000) 
K  δ  Zc method (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
Meyerhoff SPT method (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
Meyerhoff SPT method for silty sand (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
1) The β  f_{max} method (API2011)
In this method is given by the equation in which β depends on the density of the sand layer and p_{v}’ is the vertical effective stress. β values recommended by API range from 0.29 for medium dense sand to 0.56 for very dense sand. User defined value β could also be specified. This method requires also a value of f_{lim} which is the limiting value for t_{max}. API proposes flim values ranging from 67 kPa for medium dense sand to 115 kPa for very dense sand. User defined value of flim could also be prescribed.
2) K  δ  f_{lim} method (API2000)
In this method is given by the equation in which K is lateral earth pressure coefficient, is the angle of friction between the pile surface and soil and is the vertical effective stress. The values of K and δ need to be specified by the user after due consideration of type of soil, pile and method of installation. Some guidance values in this regard are given in the appendix. API recommends a K value of 0.8 for open ended pipe piles and 1.0 for closed ended piles. The recommended δ values range from 15 degrees for very loose sand to 35 degrees for very dense sand. Standards and literature would be of help in choosing the appropriate values of K and δ. K and δ displayed in the software are those recommended by the code for driven tubular piles.
3) K  δ  Zc method (IS 2911)
In this method is given by the equation .The maximum vertical effective stress is limited to the value at the critical depth Z_{c}. Z_{c} /D ratio is specified ranging from 15 for φ’ to 20 for φ’. There is provision for user defined values of δ, K and Z_{c}
4) Meyerhoff SPT method (IS 2911)
In this method for sand and for silty sand where is the average N value for the layer.
Table 17 Required properties for 'Pile Group Settlement’ with respect to ‘method for maximum side friction’ for sand
Method for maximum side friction 
Friction angle 
Shaft friction factor (β) 
Angle of shaft friction (δ) 
K Earth pressure coefficient 
Limiting shaft friction (flim) 
Standard penetration test, average value in layer 
Elastic modulus 
Poisson ratio 
β method (API2011) 
✓ 
✓ 




K  δ method (API2000) 
✓ 
✓ 
✓ 




K  δ  Z_{c} method (IS2911) 
✓ 

✓ 
✓ 




Meyerhoff SPT method (IS2911) 
✓ 



Meyerhoff SPT method for silty sand (IS2911) 
✓ 


Method for maximum base resistance: Select the method for maximum base resistance from the dropdown list. This parameter is mandatory for Pile group settlement analysis. The table below details the options available for Sand soil.
Table 18 Details of 'Method for maximum base resistance' for sand
Method for maximum base resistance 
Notes 
N_{q}q_{lim} method (API2011, API2000) 
(API 2000 RP2AWSD 2000) (API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
N_{q}  Z_{c} method (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
N_{q}  Berezantsev  Z_{c} method 

Meyerhoff SPT method (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
Meyerhoff SPT method for silty sand (IS2911) 
(IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3) 2010) 
1) Nqq_{lim} method. (API2011, API2000)
In API recommended values of N_{q} and q_{lim} are automatically displayed in the software. User may also specify values of N_{q} and q_{lim}
2) NqZc method (IS 2911)
In this method the software automatically gets the value of N_{q} for the φ value from the curve given in IS 2911. This value is used together with the specified value of Zc/D ratio to get the limiting value of q_{max}. A default value of Zc/D = 15 is used for in the software. The user has option to prescribe other value of Zc/D up to 20.
3) NqBerezantsevZc method
In this method Nq is obtained from Berezantsev’s curve using the value of φ specified. This value is used together with the limiting value of qmax using the value of Zc/D specified.
4) Meyerhoff  SPT methodIS 2911
In this method where is the average N value at the pile tip. Lb is the pile penetration in this embedment layer and D is the pile diameter. is limited to to 400 . In silty sand and is limited to 300N.
Note on average N Value:
For pile capacity estimation at various depths: Average N value at a given depth is computed using N values between 2D to +3D. If no SPT points are present in this range then the average or weighted average of the two closest points around this depth will be used. If only one SPT point is present in the entire sand layer, then the N value of this point will be used for the entire layer.
For pile capacity at the pile tip: For calculating Average N value at the pile tip, only points in the range of 2D to +3D will be used. If no points are present in this range then validation will fail.
Table 19 Required properties for ‘Pile group settlement analysis’ with respect to ‘method for maximum base resistance’ for sand
Method for maximum base resistance 
Friction angle (f) 
Limiting end bearing (q_{lim}) 
Bearing capacity factor (N_{q}) 
Standard penetration test, value at pile base 
N_{q}  q_{lim} method (API2011, API2000) 
✓ 
✓ 


N_{q}  Z_{c} method (IS2911) 
✓ 


N_{q}  Berezantev  Z_{c} method 
✓ 



Meyerhoff SPT method (IS2911) 
✓ 

Meyerhoff SPT method for silty sand (IS2911) 
✓ 
Axial analysis method: Select the ‘Axial analysis method’ using the ‘drop down menu’ for axial load analysis.
Table 20 Axial analysis method details for sand
Axial analysis method 
Method details 
API2000 
(API 2000 RP2AWSD 2000) 
API2011 
(API 2011 Geotechnical and Foundation Design Considerations April 2011, Addendum 1, 2014) 
Elastic method 
Based on elastic properties of soil. 
Table 21 Required properties for ‘Pile group settlement analysis’ with respect to 'Axial analysis method' and ‘method for maximum side friction’ for sand
Axial analysis method 
Method for maximum side friction 
Friction angle (f) 
Shaft friction factor (β) 
Angle of shaft friction (δ) 
K Earth pressure coefficient 
Limiting shaft friction (flim) 
Standard penetration test, average value in layer 
Elastic modulus 
Poisson ratio 
API2011 
β method (API2011) 
✓ 
✓ 




K  δ method (API2000) 
✓ 
✓ 
✓ 




K  δ  Z_{c} method (IS2911) 
✓ 

✓ 
✓ 





Meyerhoff SPT method (IS2911) 
✓ 



Meyerhoff SPT method for silty sand (IS2911) 
✓ 



API2000 
β method (API2011) 
✓ 
✓ 




K  δ method (API2000) 


✓ 
✓ 
✓ 




K  δ  Z_{c} method (IS2911) 
✓ 
✓ 
✓ 




Meyerhoff SPT method (IS2911) 
✓ 



Meyerhoff SPT method for silty sand (IS2911) 
✓ 



Elastic Code 
β method (API2011) 
✓ 
✓ 

✓ 
✓ 

K  δ method (API2000) 


✓ 
✓ 
✓ 

✓ 
✓ 

K  δ  Z_{c} method (IS2911) 
✓ 
✓ 
✓ 

✓ 
✓ 

Meyerhoff SPT method (IS2911) 
✓ 
✓ 
✓ 

Meyerhoff SPT method for silty sand (IS2911) 
✓ 
✓ 
✓ 
Table 22 Required properties for ‘Pile group settlement analysis’ with respect to 'Axial analysis method' and ‘maximum base resistance’ for sand
Axial analysis method 
Method for maximum base resistance 
Friction angle (f) 
Limiting end bearing (q_{lim}) 
Bearing capacity factor (N_{Q}) 
Standard penetration test, value at pile base 
Elastic modulus 
Poisson ratio 
API2011 
N_{q}  q_{lim} method (API2011, API2000) 
✓ 
✓ 




N_{q}  Z_{c} method (IS2911) 
✓ 




N_{q}  Berezantev  Z_{c} method 
✓ 






Meyerhoff SPT method (IS2911) 
✓ 



Meyerhoff SPT method for silty sand (IS2911) 
✓ 



API2000 
N_{q}  q_{lim} method (API2011, API2000) 
✓ 
✓ 




N_{q}  Z_{c} method (IS2911) 
✓ 






N_{q}  Berezantev  Z_{c} method 
✓ 




Meyerhoff SPT method (IS2911) 
✓ 



Meyerhoff SPT method for silty sand (IS2911) 
✓ 



Elastic Code 
N_{q}  q_{lim} method (API2011, API2000) 
✓ 
✓ 

✓ 
✓ 

N_{q}  Z_{c} method (IS2911) 
✓ 



✓ 
✓ 

N_{q}  Berezantev  Z_{c} method 
✓ 

✓ 
✓ 

Meyerhoff SPT method (IS2911) 
✓ 
✓ 
✓ 

Meyerhoff SPT method for silty sand (IS2911) 
✓ 
✓ 
✓ 
Relative density: Select the relative density of the sand soil from the dropdown menu. The choices are ‘Very Loose’, ‘Loose’, ‘Medium’, ‘Dense’ and ‘Very Dense’ sand. Based on the relative density selection and the ‘Axial analysis method’ selected, the application populates the recommended values for the below parameters. For API2011 and API2000 these are based on the appropriate ‘API recommended’ practices. These values can be replaced by user preferred values.
Note: For ‘Very Loose’ and ‘Loose’ sand, tz/ API2011 code doesn’t recommend any values for ‘Shaft friction factor’, ‘Limiting shaft friction (f_{lim}), Limiting end bearing (q_{lim}) and Bearing capacity factor (N_{q}). These need to be prescribed by the user based on soil investigation reports.
Properties for Sandy soil
Table 23 Soil property details for sand
Soil property 
Units 
Min value 
Max value 
Notes 
Elastic modulus of soil 
kN/m^{2} 
11000 
200000 
Default values for the particular 'relative density' will be populated when the ‘axial analysis method’ is set as ‘Elastic method’ 
kips/ft^{2} 
229.68 
4176 

Poisson Ratio 

0.1 
0.5 
Default value: 0.2 
Friction angle (f) 
Deg 
25 
45 
The value is not changed based on selection of ‘relative density of soil’ 
Shaft friction factor (b) 

0.10 
1.0 

Angle of shaft friction (d) 
Deg 
5 
45 
Details in Table 19 Values for interface friction angle δ 
K Earth pressure coefficient 

0.25 
2.0 
Details in Table 20 Guidance values for lateral earth pressure coefficient K 
Limiting shaft friction (f_{lim}) 
kN/m^{2} 
0 
400 

kips/ft^{2} 
0 
8.35 

Limiting end bearing (q_{lim}) 
kN/m^{2} 
0 
15000 

kips/ft^{2} 
0 
313.2 

Bearing capacity factor (N_{q}) 

1.5 
320 

Standard penetration test, average value in layer 
Blows/ft 
> 0 

This value is automatically calculated from the SPT table in the SPT tab. The values of 'N values' in the layer are averaged. 
Standard penetration test, value at pile base 
Blows/ft 
> 0 

This value is automatically calculated from the SPT table in the SPT tab. This is the average 'N value'  2D above pile tip and 3D below pile tip. 
Table 24 Values for interface friction angle δ
Type of soil 
Angle of pile soil friction δ (degrees) 
Reference 
Granular soil 
Tan δ range 0.7 to 1.0 
Fleming et al 
Granular soil 
Constant volume friction angle φ_{cv} 
Fleming et al Tomlinson et al 
Very loose sand Loose sand silt Medium silt 
15 
API 2000 
Loose sand Medium sandsilt Dense silt 
20 

Medium sand Dense sand silt 
25 

Dense sand Very dense sand silt 
30 

Dense gravel Very dense sand 
35 
Table 25 Guidance values for lateral earth pressure coefficient K
Pile Type 
K 
Reference 
Driven hollow Tubular steel piles 
0.8 
API 2000 
Driven cast –insitu piles 
1.2 dry concrete 
Fleming et al

1.0 wet concrete 

Conventional bored piles in sand 
0.7 

Bored cast insitu concrete 
0.7 

Continuous flight augur in sand 
0.9 

Continuous flight augur in silty sand and silt 
0.6 

Precast concrete driven 
1.02.0 (φ = 30^{o} to 40^{o}) 
IS 2911 
Driven cast –insitu piles 
1.02.0 (φ = 30^{o} to 40^{o}) 

Bored cast insitu concrete 
1.01.5 (φ = 30^{o} to 40^{o}) 
Shaft friction estimate in weak and strong rock strata.
The maximum unit shaft friction is estimated using the equation
Where α is multiplier and is the unconfined compressive strength. Default value of α in the appropriate system of units gets shown in the software however user may also specify value of α.
Base resistance in weak and strong rock strata
The maximum unit base resistance q_{max} is estimated using the expression
A default value of β = 1 is used in the software. Other values between 0.5 and 3 may be adopted based on rock discontinuities and local experience.
Axial analysis method: Select the ‘Axial analysis method’ using the ‘drop down menu’ for axial load analysis.
Table 26 Axial analysis method details for weak rock
Axial analysis method 
Method details 
Elastic method 
Based on elastic properties of rock. 
Table 27 Required properties for Pile group settlement analysis for weak rock
Axial analysis method 
Unconfined compressive strength 
α factor 
Base resistance factor 
Elastic modulus 
Poisson ratio 
Elastic Method 
✓ 
✓ 
✓ 
✓ 
✓ 
Table 28 Soil property details for weak rock
Property 
Units 
Min value 
Max value 
Notes 
Elastic modulus of soil 
kN/m^{2} 
10^{6} 
2*10^{7} 

kips/ft^{2} 
20880 
417600 

Poisson Ratio 

0.1 
0.5 
Default value: 0.2 
Unconfined compressive strength 
kN/m^{2} 
1000 
20000 

kips/ft^{2} 
20.88 
417.6 

a factor 
(kN/m^{2})^{1/2} 
3 
20 
(Focht Jr. 1973) 
(kips/ft^{2})^{1/2} 
0.433 
2.88 

Base resistance factor 

0.5 
3 
(e. a. Reese 1984) 
Shaft friction estimate in hard rock strata.
The maximum unit shaft friction is estimated using the equation
Where α is multiplier and is the unconfined compressive strength. Default value of α in the appropriate system of units gets shown in the software however user may also specify value of α.
Base resistance in hard rock strata
The maximum unit base resistance q_{max} is estimated using the expression
A default value of β = 1 is used in the software. Other values between 0.5 and 3 may be adopted based on rock discontinuities and local experience.
Axial analysis method: Select the ‘Axial analysis method’ using the ‘drop down menu’ for axial load analysis.
Table 29 Axial analysis method details for hard rock
Axial analysis method 
Method details 
Elastic method 
Based on elastic properties of rock. 
Table 30 Required properties for Pile group settlement analysis for hard rock
Axial analysis method 
Unconfined compressive strength 
α factor 
Base resistance factor 
Elastic modulus 
Poisson ratio 
Elastic Method 
✓ 
✓ 
✓ 
✓ 
✓ 
Table 31 Property details for hard rock
Rock Property 
Units 
Min value 
Max value 
Notes 
Elastic modulus of soil 
kN/m^{2} 
1.5*10^{7} 
10^{8} 

kips/ft^{2} 
313200 
2088000 

Poisson Ratio 

0.1 
0.5 
Default value: 0.25 
Unconfined compressive strength 
kN/m^{2} 
10000 
100000 

kips/ft^{2} 
208.8 
2088 


a factor 

3 
20 

Base resistance factor 

0.2 
3 

SPT tab is used to define the standard penetration test results.
The data in this tab is required for pile capacity estimation and axial load analysis for sand soil layer when 'Meyerhoff SPT method (IS2911) is selected as the 'Method for maximum side friction' or as the 'Method for maximum base resistance'.
For sand layers, the 'standard penetration test avg value in layer' is calculated by averaging the values in the layer and displayed in the soil layer tab in the ' Soil Layer Properties ' pane. This value is used when the 'method for maximum side friction' is set as one of 'Meyerhoff SPT method (IS2911)'.
When the pile terminates in the sand layer, the 'standard penetration test value at pile base' is calculated by averaging the values from pile tip – 2D and pile tip + 3D and displayed in the soil layer tab in the 'Soil Layer Properties' pane (D is the effective Diameter of the pile). This value is used when one of 'Meyerhoff SPT method (IS2911)' is selected as the ' method for maximum base resistance '.
The ‘SPT Table’ contains the corrected data from the SPT test performed.
Use the (+) and () buttons at the top of the table to add / delete rows to the SPT table.
[Organize] button can be used to sort the values in ascending order of depth and to clean up empty entries in the table.
Up to 100 SPT points can be specified in the table.
Table:
Doubleclick on the table cells to edit the content of the cells.
The table consists of three columns: No., Depth, N Value.
‘No.’ column cannot be edited and displays the entry index.
Depth Column – Contains the depth at which the test is done.
N Value Column – Contains the corrected 'N' value of the test and specified as number of blows per foot
Right click on the table to bringup the context menu to insert / delete rows in the table, cut, copy, delete and paste contents into the table. It is also possible to copy the table from excel and paste the contents into this table. Ensure adequate number of empty rows are added to the table prior to pasting contents from an excel table.
The SPT graph plots the data in the ‘SPT table’.
Test results from pile loading tests performed on a single pile on site along with base soil properties can also be used to estimate the pile group settlement. The load test involves loading a single pile with a series of loads load and determining the pile head settlements under these loads. Two parameters which are important for pile group settlement estimate are pile head stiffness (k) and pile base stiffness (k_{b}) can be obtained pile load test results.
Pile head stiffness (k) is the ratio of pile head load and pile head settlement (Pt/wt). ‘k’ should be calculated at design load. The pile head settlement under design load can be obtained from test results.
Pile base stiffness (k_{b}) is the ratio of pile base load and pile base settlement when the pile head is loaded with the design load. While we do not know these values separately, their ratio can be estimated in one of the following two ways:
i) It can be calculated as E_{s} x D/(1ν^{2}) where E_{s} and ν are the elastic modulus and the Poisson ratio of soil at the base.
ii) Base stiffness k_{b} can also be obtained from the pile load test data in the following manner. Determine the slope of the load settlement curve at a settlement corresponding to about 1.5% or 2% of pile diameter (when full skin friction would have been mobilized and further settlement is mainly due to structural compression of the pile and elastic settlement of the soil at the base. The pile base stiffness can be estimated from the expression given below:
Where
k_{b} is the pile base stiffness
k is the slope of the of the load settlement curve just after full mobilization of skin friction
L is the length of the pile
A is the area of cross section of pile
E is the elastic modulus of pile material.
Select this checkbox to use field test data instead of specifying the layerwise soil properties.
Test parameters 
Units 
Min value 
Max value 
Notes 
kN 
> 0 

Specify the design load applied on a single pile. 

kips 

mm 
> 0 

Specify the corresponding pile head settlement measured while applying the design load 

inch 
Either elastic modulus and Poisson ratio of soil at the pile base should be specified OR the base stiffness (Pb/Wb) should be specified. If all of them are specified, the base stiffness will be used for computation.
Test / Soil parameters 
Units 
Min value 
Max value 
Notes 
kN/m^{2} 
> 0 

Specify the elastic modulus of the soil at the pile base. Leave blank if not available 

kips/ft^{2} 


0.1 
0.5 
Specify the Poisson ratio of the soil at the pile base. Leave blank if not available.
Typical values Soft clay: 0.5 Stiff clay below water table: 0.5 Stiff clay above water table: 0.4 Sand: 0.2 Weak rock: 0.2 Hard rock: 0.25 

OR 

Pile base stiffness(P_{b}/W_{b}) 
kN/m 
> 0 

Specify the base stiffness of the soil at the pile base.
It is also possible to determine the base stiffness empirically by carrying out a loading/unloading test.
This is the load transferred to the base divided by settlement of the base of pile under design load.
Leave blank if not available
Note: The base stiffness data will be used if base stiff, elastic modulus of soil and Poisson ration of soil are all specified. 
kips/ft 
Reese, et al. “Analysis of a Pile Group under Lateral Loading, Laterally Loaded Deep Foundations: Analysis and Performance.” ASTM, STP 835, 1984: 5671.
Reese, L.C., and W.R. Cox. “Field Testing and Analysis of Laterally Loaded Piles in Stiff Clay.” 5th Annual Offshore Technology Conference. Houston, Texas, April 1975.
“API 2000 RP2AWSD.” American Petroleum Institute WSD, 2000.
Fleming, K, A Weltman, M Randolph, and K Elson. Piling Engineering. Third. London: Taylor & Francis, 2009.
Terzaghi, K., R. B. Peck, and G. Mesri. Soil Mechanics in Engineering Practice. Third Edition. New York: John Wiley, n.d.
Tomlinson, M., and J. Woodward. Pile Design and Construction Practice. Fifth Edition. London: Taylor and Francis, n.d.
Reese, L. C., W. R. Cox, and F. D. Koop. “Analysis of laterally loaded piles in sand.” Proceedings of the offshore technology conference (OTC 2080). Houston, 1974.
Poulos, H. G., and E. H. Davis. Pile Foundation Analysis and Design. 1980, n.d.
Turner, J. RockSocketed Shafts for Highway Structure Foundations. In:Program, N.C.H.R (Ed) A Synthesis of Highway Practice, Transportation Research Board of the National Academies, 2006.
“API 2011 Geotechnical and Foundation Design Considerations.” ANSI/API RP2GEO, April 2011, Addendum 1, 2014.
Focht Jr., John A. Koch, Kenneth. J. “Rational Analysis of the Lateral Performance of Offshore Pile Groups.” Offshore Technology Conference. 1973. Paper No 1896.
Reese, L.C. “Analysis of Laterally Loaded Piles in Weak Rock.” Journal of Geotechnical and Geoenvironmental Engineering 123 (1997): 10101017.
Terzaghi, K. “Estimation of coefficient of subgrade reaction.” Geotechnique Vol.5, no. No. 4 (1955): 4150.
Semple, R. M., and W. J. Rigden. “Shaft capacity of driven piles in clay.” Proc. ASCE National Convention. San Francisco, 1984.
Kolk, H. J., and E. van der Velde. “A reliable method to determine friction capacity of piles driven into clay.” Proc. Offshore technology conf. OTC 7993. Houston, 1996.
Randolph, M. F., and C. P. Wroth. “Analysis of deformation of vertically loaded piles.” ASCE, Geotech Eng Div. 104(GT12) (1978): 14651488.
Melonakos, G, and G Gazetas. “Settlement and additional internal forces of grouped piles in layered soil.” Géotechnique, no. 48(1) (1998): 5572.
Bowles, J E. Foundation analysis and Design. Fifth Edition. McGraw Hill, 1996.
“IS 2911 Part 4 Load test on piles.” Bureau of Indian Standards, n.d.
Van Weele, A A. “A Method of Separating theBearing Capacity of a Test Pile into SkinFriction and Point Resistance.” 4th ICSMFE. 1957. 7680.
“IS 2911 Design and construction of pile foundations  Code of Practice (Part 1. Sections  1,2&3).” 2010.