Hydraulic cylinders and bolt tensioners, produced by FPT – Fluid Power Technology are suitable for tensionong high resistance bars specifically designed for civil applications. Tensioning dywidag bar macalloy bar. The thread, made during the rolling process, does not affect the entire circumference of the bar, but only two diametrically opposite sectors as can be clearly seen from the drawing shown below. A limit of the thread is the need to tension the bars, putting them in tension and then tightening the anchor nuts. It is also possible to stretch with the use of torque wrenches (manual or hydraulic) but the losses due to system frictions (friction between the thread of the bar and that of the nut) and the high stress of torsions that act on the bar (part of the applied torque due to the mutual frictions between the bar and the nut it is transferred as a torsion to the bar instead of as traction on it) they are not recommended for use when it is desired to obtain tightening values in line with the normal technical requirements (whether they be geotechnical or structural). For the operations of tensioning dywidag bar macalloy bar FPT can supply all the complete hydraulic system including the 1500 bar high pressure hand pumps, hoses, manifolds, quick couplers and the fittings or the pneumohydraulic control units always for the use of the hydraulic tensioners. While if an hollow jack is used, the hydraulic circuit will be composed by a 700 bar hand pump with the relative couplers, hoses and fittings or an electric control unit. FPT can also provide all the technical support necessary for the study of custom made equipment to be able to meet the various needs of individual projects and customers.