How to Check And Accept Pre-stressed Strands?
Pre-stressed steel strand acceptance sampling standards 1. inspection items: surface quality, dimensional deviation, twist distance, tensile test, bending test, relaxation test. 2. Sampling methods and quantities. 2.1 Steel strand for prestressing concrete shall be accepted in batches, each batch consisting of the same grade, the same specification, the same production process made of steel strand, and the weight of each batch shall not be greater than 60 tons. 2.2 From each batch of steel strand, any 3 plates shall be taken for surface quality, diameter deviation, twist distance, and mechanical properties test. If each batch is less than 3 discs, the inspection shall be carried out disc by disc. Yield strength and relaxation tests shall be carried out quarterly on a sample basis, no less than one strand at a time. 2.3 One 750mm sample from the normal part of the end of the selected outline strand of each tray shall be intercepted for testing. 3. The results of...