Alabama & Gulf Coast Railway (AGR), a Genesee & Wyoming Company, began operations in Monroeville, AL in 1997 from Kimbrough, AL to Pensacola, FL. In 2003, AGR expanded from Kimbrough, AL to Columbus, MS with operations from Mobile, AL via BNSF Railway. They now operate a total of 442 miles of track through Mississippi, Alabama and Florida.
During a courtesy inspection along one of the tracks, AGR engineers noted that a 132-in. culvert running directly under the track had failed due to age, degradation, and poor installation methods used. The deteriorating culvert had experienced major encroachment along the toe of the slope after a major rain event and catastrophic washouts. Given this advanced degradation, AGR consulted three local contractors for proposed solutions and cost. AGR preferred a method that would allow the railroad to remain in operation while construction took place. Not only would this allow the line to continue unimpeded but would also provide substantial cost savings.
Ultimately, AGR accepted a proposal by Chase Plumbing to slipline the host culvert with 108-in. diameter Smooth Cor™, a double wall corrugated steel pipe with a polymer-coated liner and Aluminized Type 2 (ALT2) shell as well as 102-inch Tunnel Liner Plate both manufactured and supplied by Contech Engineered Solutions. The Smooth Cor was inserted on struts from the south end. During this process, a partial collapse occurred directly under the rail which required an emergency hand lining with Contech’s 7 gage, 2-flange Tunnel Liner Plate for roughly 10.5 LF. The full length corrugations and lapped joints inherent with 2-flange Liner Plate provide more effective stiffness and ring compression and was ideal for relining this portion of the culvert. Smooth Cor was then used to line the rest of the length of the host pipe for a total of 117 LF installed.
Once the host was relined, the entire structure was grouted in multiple stages with a non-shrink grout while a low maximum grouting pressure of < 5 PSI was maintained. The end result was a fully structural repair with both significant time and money saved. The original pricing for open cut and replacement was upwards of $500,000. AGR was extremely pleased with the outcome of relining the host pipe which cut the original estimated cost by roughly 40%.