Relaxation Test

In pre-tension systems (post or pre-tension), the wire or cable will bear tensile load upon applying pre-tension and this load will remain during the system’s lifetime. Thus, by the lapse of time, tension will offset. For this reason, the structure designer calculates and considers pre-tension force in the execution phase.

To measure tension offset mentioned above, tension relaxation test will be conducted.

The relaxation test is to measure changes in a specimen’s forces in comparison with the initial force (FO) at a fixed length and determined temperature.

According to standard, this temperature is 20±2°C and the test may be conducted at other temperature upon the customer’s request.

In accordance with various standards, the sample loading force quantity is 70% of nominal force or 70% of actual tolerable force of the sample which is variable upon request of the customer.

This test is conducted in 120 hours and 1000 hours routines but it may be conducted for extra times.