The main difference between a bearing bolt and a friction bolt lies in their respective mechanisms of anchoring and load transfer.
Bearing Bolt:
Load Transfer: Bearing bolts rely on bearing friction to transfer loads from the bolt to the surrounding rock or concrete. They achieve this by creating a tight fit between the bolt and the drilled hole, ensuring direct contact and load transfer.
Installation: Bearing bolts are typically installed by inserting them into pre-drilled holes and then grouting the annulus between the bolt and the hole. The grout provides additional support and helps enhance the bearing capacity of the bolt.
Support Application: Bearing bolts are commonly used in applications where the primary load transfer mechanism is through direct contact between the bolt and the surrounding rock or concrete. They are often employed in stable ground conditions where high bearing capacity and reliable load transfer are essential.
Friction Bolt:
Load Transfer: Friction bolts rely on frictional resistance between the bolt and the surrounding rock or concrete to transfer loads. They achieve this by expanding an anchor or shell within a pre-drilled hole, creating frictional resistance against the walls of the hole.
Installation: Friction bolts are installed by inserting them into pre-drilled holes and then expanding an anchor or shell at the end of the bolt. The expansion creates radial pressure against the walls of the hole, generating frictional resistance and anchorage.
Support Application: Friction bolts are commonly used in applications where the primary load transfer mechanism is through frictional resistance rather than direct bearing. They are often employed in challenging ground conditions where stable support is required, such as in loose or fractured rock.
While both bearing bolts and friction bolts are used for reinforcement and support in rock and concrete structures, they differ in their load transfer mechanisms and installation procedures. Bearing bolts rely on direct contact and bearing friction, while friction bolts rely on frictional resistance generated by expansion within the drilled hole. Each type of bolt has its own advantages and is chosen based on the specific requirements of the project and the geological conditions encountered.
