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Excalibur Screwbolts

Crossrail Trusts Excalibur Plus Bolts For Demanding Applications

When Crossrail needed a 120-year life, extra-long screwbolt that would prove non-corrosive in some of its most demanding tunnel applications, they turned to screw bolt specialist Excalibur. The British company developed the bespoke PLUS bolt, a long-lasting independently-tested bolt that is highly resistant to corrosion. It is now being used in a variety of challenging applications for Crossrail including fixing steelwork to sprayed concrete tunnel linings.

Because CrossRail tunnels are subject to C5 environmental conditions, any anchors used in the tunnel lining need to demonstrate a 120-year design life instead of the standard 50-year span of a standard fixing. As well as being highly corrosion-resistant, the twin-helix Excalibur PLUS bolt demonstrates high-performance tensile and shear characteristics. It passed 11,000 hours of salt spray tests at an accredited UKAS test house and was evaluated for nine weeks in an accelerated cyclic corrosion test by the Ford Motor Company with no signs of corrosion. Crossrail also commissioned Vinci Technology and Imperial College London’s Department of Engineering to conduct stringent testing of the Excalibur PLUS bolt to ensure it complied with their strict requirements and could withstand the stresses of a greatly extended design life in a sprayed concrete tunnel lining. The tests included tension and shear tests, cyclic tension, and mock-up simulation tests to top and side connections.

Excalibur PLUS bolts, the latest edition of the original Excalibur Screwbolt, are now being used for a variety of fixing applications across the Crossrail network including the installation of platform edge screens at Tottenham Court Road, Bond Street, Farringdon, Liverpool Street, and Whitechapel. This task requires particularly long bolts to overcome variations in the depth of the concrete tunnel lining, so Excalibur provided a longer length PLUS stud bolt to solve this problem. Installation of the screens was undertaken by a specialist firms for main contractors Laing O’Rourke, Costain Skanska JV, Bam Ferrovial Kier, and Balfour Beatty, Bemo, Morgan Sindall.

Excalibur has now produced a range of M12, 16 and 20 hexagonal head PLUS bolts for the tunnelling and marine industries. Not only are the concrete screw anchors highly resistant to corrosion, they are easy, fast and safe to install.

Excalibur is the manufacturer of the original screw bolt, the innovative high-strength twin helix threaded anchor that has revolutionised bolt fixing in the global construction. Excalibur continues to manufacture all of its products in the UK using British design and engineering expertise. The Excalibur Screwbolt range now includes a full complement of products for almost any building or construction project, from bridge and tunnel engineering to lighter second fix applications such as cable trays and signs.

2 January 2019