DYNA Force^® is manufactured based on the theory that the permeability of steel to a magnetic field changes with the stress level in the steel. By measuring the change in a magnetic field, the magnitude of the stress in the steel element can be obtained.
DYNA Force^® does not alter the characteristics of the tendon other than its magnetization. The permeability is a function of temperature and magnetization, and a calibration process eliminates the impact of these variables. The program takes into consideration the temperature change effect automatically. A portable Power Stress unit is attached to wire leads from the DYNA Force^®. This unit will create the magnetic field, measure the residual value and then convert it to a direct force reading.

The accuracy of the force measurement is within 1%.
The DYNA Force^® system is robust, requires no maintenance and has no moving parts. It is composed of sensors and a Power Stress Unit (readout box). DYNA Force^® is installed over the strand or bar during construction and a zero reading is taken before applying any post-tensioning force. It is expected to have a similar service life as the bridge/building structure. This will allow the owner to regularly monitor the forces in the post-tensioning system in minutes as a part of their inspection procedures without the need for lift-off equipment or other special expensive techniques. This will also avoid the inaccuracies and risks often associated with lift-off readings. One person can do this job.