Multi-strand sacrificial anchor testing

Ground anchors are used in many different types of structures including retaining walls, dams, wharves, bridge abutments and foundations for buildings. Ground anchors are stressed (active anchorage) to prevent structural movement and they transfer their load over a distal length.

In any ground anchoring project, site specific geotechnical investigations for the construction of the ground anchors are critical to minimise the risk profile for all parties. Access to this information means we are better able to qualify potential drilling difficulties and any potential for loss of grout from the drill hole during the anchor installation. Bonded and unbonded tendons are available. For the unbonded tendons, the strands are run through our specialist greasing and sheathing machine. This machine parts the individual wires of the strands followed by immersion into a grease bath before completely encapsulating the strand in the outer sheathing to ensure no voids are present.

We utilise the technique of high-pressure (1000psi) post-grouting in weak soils to significantly improve the bond capacity, and, where required, fabric socks are used to ensure containment of grout within the drill hole thus ensuring full bond potential is realised.

We have constructed ground anchors in accordance with internationally recognised codes that have been adopted in New Zealand which include; British Standard Code of practice for Ground Anchorages BS8081:1989, Execution of special geotechnical work – Ground Anchors BS EN 1537:2000, FIP Design and construction of prestressed ground anchorages April 1996 and US Federal Highway Administration Geotechnical Engineering Circular No. 4 Ground Anchors and Anchored Systems June 1999.

For permanent strand anchors, the strands are run through our specialist greasing and sheathing machine. This machine parts the individual wires of the strands followed by immersion into a grease bath before completely encapsulating the strand in the outer sheathing to ensure no voids are present.

We also provide mini-piles (drilled and grouted micro-piles up to 300mm diameter) which are structural supporting members that improve the stability and load bearing capacity of structures. These are constructed by drilling small diameter holes and constructing piles with high tensile steel and high compressive strength grouts to achieve tremendous load bearing capacities. Some of our equipment used to install mini-piles has been specifically designed, engineered and constructed to operate in low head room situations, which allows us to install mini-piles inside of existing buildings, factories and tunnels.

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