FREYSSINET – The inventor of the multistrand stay cable

A parallel strand system: Freyssinet invented the robust and flexible multistrand parallel system in 1976. The Freyssinet HD stay cable is based on each strand being completely independent.

This principle has many advantages, including:
• installation and tensioning of each strand individually;
• individual protection against corrosion;
• individual removal and replacement if needed.

The standard range of HD stay cables varies from 1 to 169 strands. However, there is no limit to the capacity or the length of stay cables. The largest stay cables yet installed were for the Collserola telecommunications tower in Spain (205-strands) and the longest are the stabilization stay cables for Ting Kau bridge in Hong Kong (465 m long).

The Freyssinet monostrand
A galvanised strand with a semi-bonded sheath

The tension element of the Freyssinet HD stay cable consists of a group of parallel individually protected T15.7 strands named “Freyssinet monostrand”. This patented stay cable strand has excellent durability and provides perfect protection against corrosion due to two complementary nested barriers formed by galvanisation and a semi-bonded individual HDPE sheath extruded onto the strand after the inter¬stices have been filled with a specifically developed wax.

The bundle of Freyssinet monostrands is usually contained in an HDPE (High Density PolyeEthylene) co-extruded outer pipe specially designed to satisfy stay cable needs and give excellent durability.