Device and method for controlling a prestressing jack when tensioning a tendon

Abstract

A device and a method for controlling a clamping press is provided when clamping a tension member as a function of the clamping force of a reference clamping member. The device has a hollow, cylindrical housing, wherein a piston coupled to the reference tension member is supported longitudinally displaceably along an axis. The housing and the piston encompass a pressure chamber that can be acted upon by a pressure medium for performing an axial stroke motion of the piston against the clamping force of the reference tension member by an inlet, and that can be connected by an outlet to the clamping press. The device further comprises a valve unit for controlling the application of the pressure medium to the clamping press, wherein the valve unit can be directly controlled by the stroke motion of the piston. The method according to the invention provides for clamping the tension member as a function of the clamping force of the reference tension member by the cylinder piston unit, the piston thereof holding the reference tension member in a predetermined stress state. When a uniform stress state is achieved in all tension members in the course of clamping the tension member by a clamping press, the inflow of the pressure medium to the clamping press is directly interrupted by the stroke motion of the piston.