Pile Capacity and Loading

The pile capacity and loading tab allows the input of the pile diameter and capacity as well as the definition of the applied loads from the associated column. The tab layout is:

Integrated Tab

Standalone Tab

Common Inputs

Pile Diameter (mm)

Change Nominal diameter/width of pile. 

This parameter specifies the diameter for circular piles or the width for square piles within the group. 

Pile Working Load (kN)

Change pile safe working load (unfactored). 

This is an essential input representing the allowable service compression load for an individual pile, expressed in kilonewtons. The module is specifically designed for use with compression-only piles.

Pile c/c spacing (dias)

Change Spacing of piles centre to centre (1.5 to 6. Normally 3).

This defines the centre-to-centre distance between adjacent piles, expressed as a multiple of the pile diameter. For friction piles, the minimum recommended spacing is typically 3.0 diameters, whereas for end-bearing piles, this can be reduced to as low as 1.5 diameters.

Minimum Number of Piles 

Change minimum number of piles in cap. 

This setting allows the user to stipulate the least number of piles required for the cap (supporting groups from 2 to 9 piles). 

End Bearing Piles

Piles are end bearing when enabled. Friction piles have spacing limits to BS 8004:2015 CI 6.3.3.1 & CI 7.3.4.5. 

The mention of "End Bearing Piles" relates to the fact that these piles allow for the tighter 1.5D minimum spacing compared to friction piles.

Integrated Options

Load Case

In the integrated module, this refers to the specific ultimate limit state (ULS) load cases imported from the full MasterFrame structural analysis. The design is linked to these cases to ensure the cap can resist the established forces.

Scan for Critical Loadcase 

Current Brief

This function automatically identifies the most onerous load case (the one producing the dominant forces) specifically for the individual pile cap design currently being viewed or edited.

All Briefs

This is an option used in conjunction with the critical loadcase scan. It allows the software to identify critical loads for every unique pile cap design (brief) contained within the project file simultaneously, rather than just the one currently selected.

Pile Cap Orientation (deg) (Integrated)

This setting allows the user to rotate the pile cap geometry by a specified number of degrees. This ensures that the forces derived from the analysis model are correctly aligned with the local axes and geometry of the pile cap.

Load Categories and Definitions (Standalone)

Dead Load (Gk​)

These are permanent actions on the structure, such as the self-weight of structural elements, finishes, and fixed equipment.

Imposed Load (Qk​)

This represents the primary variable actions, such as occupancy loads or, in the case of crane bases, the weight of the load being lifted.

Accom Imposed Load (Qk​)

This refers to accompanying variable actions. In Eurocode design, when multiple variable loads act simultaneously, one is treated as the "leading" variable action while others are "accompanying" actions, often adjusted by a ψ factor to account for the lower probability of them all reaching their maximum values at the same time.

Old Manual

Pile Inputs

The required inputs are:

• Pile diameter – the diameter, in mm, of the circular piles
• Pile Working Load – the safe working load (SWL) of the pile, in kN
• Pile c/c spacing – the pile spacing, as a multiple of the pile diameter (min 1.5, max 6)
• Minimum number of piles – set the minimum number of piles to be used in the pile cap

Load Cases

Unlike the standalone module, which requires the user to input a loading to be considered in the pile cap design, the integrated design module is linked to the loadcases used as part of the full MasterFrame analysis. Hence there are no loading inputs under the pile capacity and loading tab, but instead there are options to view the design outputs for each ultimate limit state loadcase.

Scan for Critical Load Case

The scan for critical loadcase will identify the critical loadcase for the pile cap design. This can be done for the current pile design, or for all design briefs currently applied in the model.

A further additional input for the integrated design is to specify the column orientation relative to the pile cap. While in the standalone design the major and minor input are specified by the input value, effectively defining the orientation of the column and/or pile cap, the column orientation is defined in a MasterFrame model by the column beta angle. Therefore, to define the force inputs relative to pile cap, it may be necessary to rotate the pile cap. This is done by selecting an orientation, in degrees, using the orientation drop down. The pile cap orientation is reflected in the graphical screen to aid orientation.