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2013WinShotcreteEMag

2012 Outstanding Underground Project cSX Pinkerton tunnel By Dennis Bittner, Nick Laviolette, and Denis ‘Dan’ Laviolette A Markleton, PA, was to be removed because was not a viable alternative, it was decided thatBecause detouring freight and long-distancepassenger trains running through this tunnels part of the National Gateway ClearanceProject, the Pinkerton Tunnel, located in it did not have the required height clearance to immediate interim repairs would be needed to keep accommodate double-stack freight railroad cars. this major artery for CSX Transportation open An excavation adjacent to the existing tunnel was until the adjacent new alignment was completed. planned to provide a new alignment for the rail- LRL Construction Company was brought on road track. Pinkerton Tunnel, constructed in 1884, board to perform these repairs. Nick Laviolette, had an arch shape spanning over the track and their Project Manager, together with the tunnel was lined with stone masonry walls and brick design team employed by the railroad, developed arches. After starting the removal process, large a solution that involved adding structural support pieces of the tunnel’s brick liner began to loosen to the tunnel by shotcreting 8 in. (200 mm) thick and some fell on the single railroad track that continuous leg-arch-leg supporting ribs on 4 ft occupies the tunnel. In addition, large cracks were (1.2 m) centers within the tunnel. A 4 in. (100 mm) forming throughout the 1080 ft (329 m) tunnel, layer of shotcrete, with material supplied by and the situation was deteriorating. Quikrete, was then placed between the ribs. With Fig. 1: Ribs 8 in. (203 mm) thick with 4 in. (102 mm) of Fig. 2: Nozzlemen placed 100 bags of shotcrete a day, shotcrete in between were placed sometimes working on steep slopes 28 Shotcrete • Winter 2013


2013WinShotcreteEMag
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