Railroad Timber Bridge Repair in Remote Northern Canada

01 · THE CHALLENGE

Aging Timber Rail Bridges, Far From the Road

Many short and medium span rail bridges in rural Canada still stand on timber piles, caps and stringers. Many are near or past their original design life and show decay, checking, splitting and freeze-thaw damage. Creosote use has been restricted at water crossings, which leaves timber more exposed.

On the bridges in northern Manitoba, damage was concentrated near or just above the waterline, and several piles needed repair over their full height. Cold, snow and limited access made heavy equipment costly to bring in. Pile sizes varied even within one bridge, and braces and framing crowded many piles, so rigid prefabricated jackets were a poor fit.

03 · THE RESULT

Rail Bridges Kept in Service, and Pile Caps Next

Western Infrastructure Renewal crews typically finished two or three piles a day, including travel and setup at remote sites, and some 300 piles have been repaired to date. The companion 2024 IABMAS paper reports 135 of them on eight bridges in 2023. Several of these bridges had been candidates for replacement at costs of several million dollars; the FRP program extended their service life with minimal disruption to rail operations.

The method rests on tested ground. In full-scale tests for the Nebraska Department of Roads, damaged timber piles repaired with FRP laminates carried 5.3 to 9.9 times their design load, and the U.S. Army Corps of Engineers tested PileMedic® over a three-year study.

The same FRP approach has since been extended to timber pile caps. On three municipal bridges in Saskatchewan, split pile caps were U-wrapped in place with 4 ft bands of biaxial glass fabric and structural epoxy, overlapped 12 in. On another remote bridge, a rotted 14 x 16 in. pile cap was rebuilt in the contractor's shop, fully wrapped and set back on the piles.