TS EN 523

TS EN 523 is the standard for the terminology, requirements, and quality control of steel strip sheaths and their connectors used with prestressing tendons in prestressed concrete structures. In post-tensioned systems, these components form the duct that houses the tendon, so their geometry, continuity at joints, and manufacturing quality are important to reliable stressing and subsequent protection operations.

Sheaths and connectors covered by the standard

The scope covers uncoated, cylindrical steel sheaths with a corrugated profile and a nominal internal diameter of up to 130 mm, together with the connectors assembled to form ducts. The key technical distinction is that the sheath provides the duct path while the connector maintains continuity across sheath lengths. Application is limited to sheaths and fittings made from interlocked or welded steel strip; plastic sheaths are excluded.

Technical context in prestressed concrete

In prestressed concrete, a tendon is tensioned so that the finished structure benefits from compressive force introduced into the concrete. The sheath helps position the tendon correctly and leaves the required void around it after stressing. For this reason, dimensional stability, joint arrangement, and the corrugated steel strip form are important in practice. TS EN 523 defines this product family and its quality-control framework, while explicitly noting that seals between sheaths and couplers are outside its scope and may be governed elsewhere.