Strands, Wedges and Corrosion Protection

DYWIDAG Stay Cables use strands that meet the requirements of the fib and PTI-Recommendations for stay cables, ASTM, BS as well as other national or international standards.

Generally, for both anchor types, strands have the following characteristics:

• consisting of 7 cold-drawn galvanized wires
• diameters up to 0.62" and steel grades up to 1860mm²
• with low relaxation
• PE-coated and waxed

If required, epoxy-coated strands may also be used with either  one of the cable systems.
Strands are anchored with specially treated 3-part wedges which are characterised by a high fatigue resistance.

Outer Sheathing

Standard HDPE-pipes are typically used for the outer casing of the DYWIDAG Stay Cables. They serve as a protection against environmental influences and reduce the wind loads on the cable. The pipes may be supplied in a wide variety of UV-resistant colors. They can also be provided with an outer helix to suppress rain-wind induced cable vibrations.

Steel or stainless steel pipes are available on special request.

Clevis Anchorage

For special cases, DSI developed a compact clevis anchorage that is easy to install.

Bearing and Dampers

Elastomeric bearings near the anchorages reduce the bending stresses in the anchorage zone and act as dampers against cable vibrations.

DYWIDAG stay cables can be equipped with devices that allow the immediate or later assembly of external dampers.
DSI will provide additional damping devices to reduce cable vibrations on request.

Installation

• DSI has developed various methods to optimize and simplify the cable installation procedures depending on site-specific space and time constraints.
• Prefabrication of the cables on site:
  This method is preferably used for short cables. They are lifted into position with cranes. Because of favorable site conditions, at the Alamillo cable stayed bridge in Spain, 300 m long locally prefabricated cables could be installed using a winch.
• Pushing of strands into prefabricated sheathing:
  The sheathing is prefabricated on site and brought to the inclined position in the bridge. The strands are then pushed in one by one using a light pusher.
• Pulling in strands into prefabricated sheathing:
  Here also the prefabricated sheathing is brought to the inclined position. The strands are pulled in one using small winches.