# Bolt Shear Strength

The **Shear Strength** of a bolt can be considered in the analysis, for any of the bolt types in **SWedge** (except the Simple Bolt Force model).

To consider bolt shear strength:

- Select the "Use Shear Strength" check box, for a bolt property type in the Bolt Properties dialog.
- Enter a value of shear strength. The shear strength is simply entered as a force.

The shear strength of a bolt, refers to the shear capacity perpendicular to the axis of the bolt (i.e. what shear force would be required to shear through the cross-section of the bolt), as shown in the figure below.

Shear force **F** required to fail bolt

## Bolt Shear Strength Implementation

If bolt shear strength is considered, it will be implemented in the analysis as described in the Bolt Support Force topic in the Theory section.

- The shear force will only be applied if a bolt intersects a shearing (sliding) plane of a wedge. This corresponds to bolt failure modes D, E or F (as illustrated in the Bolt Support Force topic).
- Shear force will NOT be applied if a bolt intersects a dilating plane (failure modes A, B or C).
- If shear force is applied, the direction of the applied shear force will always be exactly opposite to the sliding direction of the wedge.

## Bolt Efficiency and Shear Strength

Note that Bolt Efficiency is NOT used in conjunction with the **Bolt Shear Strength** option. If you have selected the "Use Bolt Shear Strength" option, and the bolt failure mode is D, E or F, so that the Bolt Shear Strength is applied, the Bolt Efficiency DOES NOT multiply the shear strength. The Bolt Efficiency is only used as a factor for the tensile bolt capacity determined from the Bolt Force Diagram. It has no effect on the Bolt Shear Strength.