The City of Fort Collins (Colorado) recently completed construction of a tunnel underneath BNSF Railway tracks to connect more than 30 miles of trails. The prospect of tunneling under an active rail line is a pretty big deal, and the railroad had strict requirements. The original concept of the tunnel was modified by the contractor and their engineer to utilize secant pile retaining walls to allow the construction of the portals closer to the rail line and decreasing the overall tunnel length. The tunnel was constructed by BT Construction and Lithos Engineering was their design engineer. Yenter construction was responsible for the retaining walls, including segments of sheet pile wall used to start things off. Anderson Drilling constructed the shafts for the secant pile wall and for the thrust wall. Read more about the project at TBM.
A Novel Approach at Niagara: Robbins TBM Stands Up to Challenging Ground with Custom Lining and Ground Support
This article describes the challenges faced by the World’s largest hard rock TBM (47.2-ft in diameter) as it tunnels through some very difficult geology while constructing a massive tunnel under Niagara Falls for hydroelectric power […]
This is a great little time lapse video from WSDOT that shows the construction of the tunnel behind the Bertha’s disassembly pit for the Alaska Way Viaduct Replacement Project. Related
The New York MTA’s East Side Access Tunnel Project is what I would refer to as a ‘Mega Project’. Any time you’re in the Billions of dollars range, I’d say that qualifies, and this one […]