Samples are cut at a set frequency, commonly one per 500 feet of seam, then split into coupons tested in the field and at a lab. A failure triggers tracking samples on either side until passing results bound the bad length, which is then capped or rewelded. Every sample leaves a hole to patch, so frequency balances proof against damage.
Destructive test failed at station 450, so pull bounding samples ten feet each side.
CQA picks the locations and good monitors do not announce them early, so every foot of seam has to be welded as if it will be cut.
Also heard as
- destructive seam test
- DT
Related terms
Destruct
Installer shorthand for a destructive seam sample, and for the job of cutting one out.
Peel test
Seam test that pulls the top sheet away from the bottom sheet across the weld to check how well they fused.
Shear test
Seam test that pulls the two sheets apart in their own plane, loading the whole weld in shear.
Coupon
Narrow strip cut across a seam sample for peel or shear testing, usually one inch wide.
CQA
Construction quality assurance: independent monitoring and testing that a geosynthetic system was built as designed.