Halcrow provided support to Traylor Bros Inc following the award of a contract to construct 2.1km (1.3miles) of twin bore, segmentally lined running tunnels. The tunnels have an internal diameter of 5.74m (18.8ft), and a structural thickness of 266mm (10.5”). The lining is fully bolted and gasketted for construction behind a pressure balance TBM.

Halcrow’s services covered design optimization of the tunnel lining, including revised segmentation, design of a steel fibre reinforced concrete segment alternative option, and development of a specification and testing requirements.