Dyckerhoff & Widmann Aktiengesellschaft

Erich Richartz

Reinhard Klockner

Hans-Peter Von Allmen

A method of producing an intended breaking point at a predetermined location of a tension member for a soil anchor of a strain-hardened steel or a steel which is not which is not in a thermodynamic equilibrium, for example, a wire or a steel wire strand, to enable removal of the free steel length after use by applying a tensile force which exceeds the working load. The predetermined breaking point is obtained by heating the tension member at a predetermined location in a controlled manner to a temperature at which the state of strain-hardening or the state of being not in a thermodynamic equilibrium is at least partially cancelled, wherein the predetermined breaking point has a breaking load which is equal to or smaller than the breaking load of the untreated tension member, but greater than the yield point of the untreated tension member.

Method of producing an intended breaking point in a tension member for a

In the production of a hot-rolled steel bar, such as a concrete reinforcing bar, a continuous thread is formed on the bar. The thread is arranged so that an anchoring or connecting member with a female thread can be screwed onto the male thread formed on the bar. Initially, first ribs are hot rolled on the bar surface with the ribs located on opposite sides of the bar and extending only for a portion of the circumference of the bar. Immediately following the formation of the first ribs, second ribs are hot rolled extending between and interconnecting the first ribs whereby the first and second ribs form a continuous thread. The ribs are formed in a unit made up of adjacent roll stands, each containing two rolls, the axes of the rolls in one stand are offset by 90.degree. to the axes of the rolls in the other stand. The rolls are interconnected so as to move together. The rolls in each roll stand form a roll gap with shaped surfaces on the rolls for defining the partial ribs forming the continuous thread.

Growing community of inventors

Munich, Germany

Erich Richartz