This was a challenging project in terms of access, logistics, ground conditions and design at Belfast Harbour. The type of conditions where Ischebeck Titan ground anchor solutions are regularly called for. In 1990 a ground investigation near to the site was undertaken and the bore hole records showed mixed, variable and challenging conditions.
This was the only site investigation that was available. Byland Engineering Ltd were commissioned by Quinn Piling Ltd to undertake the element design of 11 No permanent ground anchors. The ground anchors are required to support an approx 34m long section of new sheet pile wall installed in front of the existing ‘failing’ wall as part of the Wing Wall remedial works at West Twin Wharf.
• All 11 anchors are designed for FServ;k = 1,135kN and FULS;d = 2,000kN.
• All 11 ground anchors comprise Ischebeck Titan 103/51 self-drill bar with 220mm expendable drill bits.
One of the key parameters for the ground anchor design is the grout to ground bond capacity adopted, which dictates the geotechnical capacity of the ground anchors. One preliminary investigation test was undertaken on a vertical sacrificial anchor to validate the ground conditions, the drilling system and the grout to ground bond values. The vertical test anchor incorporated a 175mm expendable drill bit, was 24.5m deep and it extended ~3m into sandstone bedrock. The drilling and installation process went well, and full grout flush was maintained throughout the operation. The driller was also able to note when the sandstone bedrock was encountered at 21.5m depth, approximately 1m higher than expected.
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