HK High-Speed Rail Hides Use of Defective Expansion Anchors

On April 10 Australian anchor system manufacturer Hilti warned its contractor that the use of 3 defective HSL-3 M24 series of anchors in Hong Kong High-Speed Rail produced during May 2011 through August 2013 may reduce the tension capacity largely by 60-70% though without influencing the shear strength.

Diameters of the expansion anchors involved are from 3mm to 24mm (the longest and 1.4kg in weight). Every piece costs RMB260-298 and is usually used on the fixation of large-size components on concrete. The design of the expansion anchor is for gripping the concrete tightly with expansion of the screw anchor when the conical unit inside is reversely turned. The notice explained that the cause of such problem was the insufficient friction coating on the conical unit making it unable to achieve complete expansion to grip the concrete tightly.