Multistrand Anchors

Equipment and Anchor Accessories

Uncoiler

For projects where anchor placement by overhead crane is impractical, DSI can provide a hydraulically powered uncoiler. A unique feature of the DYWIDAG Uncoiler is the adjustable hub, which simplifies the process of placing the anchor in the uncoiler. If necessary, the uncoiler can be used to remove the anchor from the drill hole. Use of the uncoiler, both in installation and/or removal, will reduce the risk of damage to the tendon.

Spacers, Centralizers

The purpose of a spacer is to help insure that grout surrounds each strand for corrosion protection and for bond strength development. Designers should specify the desired distance between spacers (typically 7'-10').

Stressing

For installation and stressing efficiency, most DYWIDAG Jacks for multi-strand anchors are equipped with internal strand guide tubes with automatic strand gripping and releasing devices. These features make installation a fast, one step operation with small wedge seating loss. For safety, all jacks feature a check valve, which holds the pressure in the unlikely event of hydraulic failure. For reliability, the jacks are equipped with special devices for power seating all wedges simultaneously. Jacks also allow bleed-back to achieve full utilization of the maximum allowable stresses in the anchor. A hydraulic connection and a pressure gauge are provided for all tensioning jacks. The hydraulic used in conjunction with the jacks can be operated by remote control. Jack chairs are provided where wedge plate lift off during anchor testing is anticipated.

Centralizers are placed over the assembled strand bundle in order to maintain the required spacing between the anchor and the borehole so that an adequate thickness of grout (minimum 0.5") surrounds the anchor. A wide variety of centralizers are available depending upon the anchor type.