What Is a Friction Bolt?

What Is a Friction Bolt?

A friction bolt, also known as a rock bolt or an expansion shell anchor, is a type of anchor used in construction and mining industries to provide reinforcement and support in rock or concrete structures. It consists of a threaded rod with an expandable shell at one end and a nut and washer at the other.

Here's how a friction bolt typically works:

Installation: A hole is drilled into the rock or concrete structure where reinforcement or support is needed. The friction bolt is inserted into the hole, with the expandable shell positioned at the end.

Expansion: Once the friction bolt is inserted, the nut at the opposite end is tightened, causing the expandable shell to expand radially against the walls of the hole. This creates friction between the bolt and the surrounding material, providing anchorage and support.

Reinforcement: As the bolt is tensioned, it applies pressure to the surrounding rock or concrete, helping to stabilize and reinforce the structure. This is particularly useful in preventing roof or wall collapses in underground mines, tunnels, and other rock engineering applications.

Friction bolts are often used in conjunction with other support systems such as mesh, shotcrete, or cable bolts to provide comprehensive reinforcement and stability in challenging geological conditions. They are valued for their simplicity, reliability, and effectiveness in securing rock and concrete structures against potential failure.