DYWIDAG-Systems International Australia develops Vertical Grouting Rig for Pregrouted, High Strength, 75mm Ø DYWIDAG Micropiles
In the south of New Zealand‘s North Island near the town of Transmission Gully close to Wellington, an important part of the 110km long Wellington Northern Corridor Road is being built. This new road will ensure a more efficient road connection between Levin and Wellington. The 27km long, four lane motorway section will run from Mackays Crossing via Transmission Gully to Linden and includes four intersections and two new link roads.
DYWIDAG-Systems International Australia was asked to design, produce and supply special 75mm Ø pregrouted DYWIDAG Micropiles for an unusual project in the new section. The DYWIDAG Micropiles are to be used as passive bond anchors in the foundation of one of the new bridges in Transmission Gully.
This region is renowned for its small and large earthquakes. Therefore, the foundation of the bridge was designed to withstand an earthquake of 8 on the Richter Scale.
The anticipated vertical motion was controlled in the design by using the massive weight of the concrete foundation block, which is exceptionally large to have enough self-weight. The horizontal stability is established by 23m long, 75mm Ø pregrouted DYWIDAG Anchors.
In the design, DYWIDAG-Systems International fulfilled both the British standard for ground anchoring BS8081-2015 as well as the New Zealand Road Authorities design standard. The designers also specified additional requirements by adding a minimum grout cover of 20mm between anchor bar and corrugated sheathing. DYWIDAG-Systems International therefore chose to use a corrugated HDPE sheathing with an inner diameter of 127mm and an outer diameter of 145mm for 200mm Ø drilled holes.
The site requirements were very tight with limited room for deviation during production and installation. The strict use of the BS8081, paragraph 188.8.131.52 criteria required sub-vertical grouting during factory grouting.
DYWIDAG-Systems International designed, built and used a special new hydraulic grouting rig that can tilt from horizontal to vertical, while accommodating 6 preassembled 75mm Ø grouted DYWIDAG Micropiles.
Due to the increasingly higher loads acting on buildings, dams and in earthquake areas, the large diameter pregrouted DYWIDAG Bar System will undoubtedly be used more frequently in the future.