Bolt tensioning
The method of tightening bolts with hydraulic bolt tensioner has been used since the 1960s
Today, tools have been developed to the point where the method is reliable and cost-effective as well as requiring less space. By tensioning the bolt longitudinally and then fitting the nut, the desired result is achieved directly. That is, an extension of the bolt.
The number of tensioners used when tightening a bolt connection determines the quality and time required. A screw/tool ratio of 100% or 50% gives more reliable results.