Pre-Tensioning
In the Define Bolt Properties dialog, a pre-tensioning force can be defined for the following bolt types:
Pre-Tensioning Force
To define a Pre-Tensioning Force enter a non-zero value in the Pre-Tensioning Force edit box in the Define Bolt Properties dialog. A pre-tensioning force is implemented as an initial axial force assigned to each bolt element of a bolt.
- For Fully Bonded, Swellex/Split Set and Tieback bolts, the bolt elements are determined by the intersections of the bolt with the finite element mesh.
- For End Anchored bolts, the entire bolt is a single element.
Constant Force in Install Stage
If you select the Constant Force in Install Stage checkbox, then the force in the bolt will remain constant and equal to the Pre-Tensioning Force for the stage at which the bolt is installed. The stresses in the rock will NOT affect the bolt stress or displacement, at the install stage for the bolt. In subsequent stages, the bolt stress can change.
If the Constant Force in Install Stage checkbox is NOT selected, then the bolt stress in the install stage will NOT necessarily be equal to the Pre-Tensioning Force, it may change according to the stress in the rock.