Construction Grouts Used in Pinkerton Tunnel Concrete Repair Project
Posted by Matt Milos on Sep 20th 2016
Project: Pinkerton Rail Tunnel
Engineering Firm: Gannett Fleming
Contactors: GeoBuild, LLC
Overall Project Manager: Paul J. Lewis
Project Principal: John W. Kovacs
Design Project Manager: Jonathan D. McHugh
Construction Project Manager: Jack Hiller
A/E Field Representative: Matthew B. Morris
Challenge: Provide an engineered solution to renovate and reopen the Western Maryland Railway’s abandoned Pinkerton tunnel to repurpose it for trail use on the Great Allegheny Passage.
Solution: Repair the tunnel concrete liner by applying BASF Emaco S 488 using a Quikspray carrousel pump.
The Great Allegheny Passage is a 150-mile trail for bikers and hikers that connects Cumberland, MD to Pittsburgh, PA. The Pinkerton Tunnel is part of the trail corridor but has been closed off since the 1990s. The tunnel was in danger of collapsing due to deterioration of the bedrock and existing concrete liner, as well as other structural defects and drainage issues. Built in 1911 as part of the Western Maryland Railway, the 849-foot tunnel is located between the Pinkerton Low and High Bridges at Pinkerton Horn, a peninsula formed by bends in the Casselman River. Because of the closed tunnel, the trail was forced to take a 1.5-mile looping detour.
In April of 2015, the engineering firm of Gannett Fleming of Pittsburgh and the contractor, GeoBuild of Columbus, began work to restore this structure. GeoBuild specializes in geotechnical and structural construction, and this project had unique challenges including difficult access to the site.
To meet the challenging demands and tight schedule of this project, GeoBuild asked The Chas. E. Phipps Company of Cleveland to assist with providing the appropriate materials for the job. To repair the east and west tunnel entrances, Geobuild used a Quikspray carousel pump to spray-apply BASF Emaco S 488 CI repair mortar. This method allowed five men to apply 112 cubic ft of material up to 34-feet high in 10 hours. To protect the walls from the weather, Geobuild coated the repaired areas with ChemMasters Epoxy Urethane System (ChemMasters Safe Cure and Seal EPX and ChemMasters Duraguard 310 top coat). GeoBuild also installed a monolithic galvanized steel arch and injected a lightweight urethane grout, generally ranging from 3” to 5”, that filled any voids. American Wick Drain Site Drain 110 was installed inside the arch. This single-sided filter fabric allows any water that enters to flow to the designated drain exits. After installing the liner, GeoBuild injected Greenstreak’s Leak Master water swelling sealant into any remaining leaking joints.
This successful project was completed in September of 2015, and the tunnel is now open. Outdoor recreationists no longer have to take the 1.5-mile detour. Instead, they can now enjoy this piece of history and can take in exceptional sites as they travel the unique bridge-tunnel-bridge feature of the trail.
