DYWIDAG THREADBAR® Anchors with Single Corrosion Protection SCP
Single corrosion protected anchors are used for temporary anchors and sometimes for permanent anchors in non-aggressive rock or soil. A HDPE or PVC sheathing covers the free stressing length. The THREADBAR® is coated with a corrosion inhibitor before the polyethylene sheathing is installed. The bond length is covered with cement grout.
DYWIDAG THREADBAR® Anchors with Double Corrosion Protection
Double corrosion protected anchors are recommended for anchors with a long service life and for an environment where aggressive materials or stray electrical currents are expected. A corrugated high strength HDPE sheathing with plastic end caps is installed over the full length of the anchor. The annular space between THREADBAR® and HDPE is fully grouted before the anchor is installed. To accommodate the bar elongation during stressing, a short length of THREADBAR® is left free of the corrugated sheathing under the stressing anchorage. A steel pipe welded to the anchor plate and filled with corrosion preventive compound or grout protects the free end of the bar against corrosion.
A smooth plastic sheathing is installed over the corrugated sheathing in the stressing length. This allows the tendon to elongate during stressing.
The corrugated plastic sheathing acts as a protective membrane preventing intrusion of any corrosive substances. The cement grout around the THREADBAR® provides corrosion protection by embedding the bar in an alkaline environment. The THREADBAR® deformations minimize the width and control the distribution of any cracks that develop in the free stressing length, fully maintaining the protective action of the grout cover.
A protective plastic or steel cap filled with a corrosion preventive compound is installed over the anchor nut after stressing, completing the full encapsulation of the anchor tendon. The cap is removable for checking and/or adjusting the force level in the anchor tendon at any time in the future.