Abstract – Modern building technologies (for example
prestressed concrete to produce beams, floors, bridges, or
installation, testing and monitoring of ground anchors)
require the use of accurate force machines (hydraulic jacks).
One component of successful building works is a correct
and accurate calibration procedure of hydraulic jack for
tensioning cables or anchors. This article analyzes two
different calibration methods: By means of hollow load cell
and thread bar and calibration in the closed frame.
We analyze these methods using different accessories
and their influence on the uncertainty of calibration results.
As a very important part of calibration procedure is a correct
choice of the calibration mathematical model (interpolation
curve force-hydraulic pressure and hydraulic pressureforce),
there is a need to use a special software. Such is the
developed software FORCE-401-S which permits to
communicate the measurement line “load cell-amplifiercomputer”;
to choose the correct interpolation polynom;
enable to compute the errors and uncertainty values and
build the table of calibration results.