Dyckerhoff & Widmann Aktiengesellschaft

Rochling Haren Kg

Berthold Bolmer

Thomas Herbst

Lorenz Schnitzler

Hartmut Von Grolman

Anton Lugering

An anchoring arrangement for use in underground mining or foundation work or as a reinforcing element for concrete includes a rod-shaped tension member of composite fiber material which has, over at least an anchoring portion thereof, a helically extending external thread with ribs formed by impressing valleys in the tension member. An anchoring member having a corresponding internal thread can be screwed onto the tension member. For obtaining a radial pressure on the tension member as a result of a wedge effect, the angle of inclination of the sides of the thread relative to the longitudinal axis of the tension member is smaller than 45.degree.. The thread preferably is a fiat trapezoidal thread. In an anchoring member which is stiff relative to circumferential tensile forces, the flat angle of inclination of the sides of the thread increases the radial pressure acting on the tension member, which leads to an increased effect into the depth and a higher resistance to shearing. The anchoring member may have a changing circumferential tensile stiffness over the length of the threaded engagement with the tension member, so that the anchoring member can expand at the point of highest stress concentration, with the result that a change in length of the tension member may occur.

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Haren, Germany

Berthold Bolmer