Tutorial 1: Calculating the capacity for a group of piles

Example 12.22 - Principles of Foundation Engineering. Braja Das.

The figure shows the cross-section of a group of 3 x 4 piles in layered saturated clay. The piles have a square cross-section of 356 mm × 356 mm and a center-to-center spacing of 889 mm.

Determine the allowable load capacity of the pile group using a safety factor of 4. Note that the water layer is on the surface of the ground.

1. Whether you’re in My Workspace or at a project work location, go to the App.
2. In the left panel, find the list Models and click the New Model button to open the menu. Next, select Deep Foundation and choose the Pile Group template.

1. In the right-hand panel, locate the Type of analysis section and make sure the Pile group option is turned on.

1. In the Foundation Soil section, expand Layer 1 by clicking on it. Next, select Cohesive as the analysis condition and enter the values for Undrained Cohesion, Unit Weight, Saturated Unit Weight, Thickness and choose a Color for the layer. Repeat for Layer 2.
2. Set the groundwater level to zero.

1. In the Structure section, select the pile cross-section as Square, and then enter the side length and the pile length.

1. Then, in the Pile Group section, enter the number of piles in the X and Y directions, as well as the spacing between them.

For this example, the value of the battery charge is irrelevant. Leave the default value.

1. Once all parameters have been set, verify that the structure looks as expected.
2. Click the icon at the top of the right panel to run the model.
3. The Results tab will be activated and will display the results of the analysis.

Below is a summary of the key variables and their expected versus obtained values.

• Das, B. M., & Sivakugan, N. (2018). Principles of Foundation Engineering.