Acrow’s modular steel truss system used in rehabilitation of bridge in Qué.

Acrow’s modular steel truss system used in rehabilitation of bridge in Qué.

TORONTO — Acrow, a bridge engineering and supply company, noted that a steel truss system it designed was used to provide support to Pont Perrault during the project to rehabilitate the historic covered bridge in Québec. Although it had been many years since the bridge carried vehicular traffic, it was closed to pedestrians and cyclists in 2018 after damage to timber components was discovered.

Pont Perrault opened to traffic in 1929 and spans the Chaudiere River in the parish municipality of Notre-Dame-des-Pins. At 150.9 metres long, it is the longest covered bridge in the province, and a major draw for tourists. After delays due to sharp increases in the cost of building materials during the global pandemic, the project began in May 2022 and was completed in November 2022. The repair work enabled the reopening of Pont Perrault for year-round use by pedestrians and cyclists, as well as ATV and snowmobile enthusiasts.

Owing to Acrow’s participation in numerous historic bridge rehabilitations across North America, it was contacted by project contractor Cité Construction TM Inc. to design and supply a freestanding structure to fit inside Pont Perrault to provide support to the covered bridge for the duration of the restoration. Acrow’s modular steel truss system, rented to the contractor, was 152.4 metres long with an overall width of 2.7 metres, and a timber deck for worker access. In addition, temporary scaffolding underneath the bridge was cabled to and supported by Acrow’s structure, allowing exterior work on the underside of the bridge to proceed safely.

As is frequently the case with the restoration of historically significant structures, the project presented challenges. At the design stage, the enormous wind load necessitated the fabrication of custom sway braces for the truss system. The installation was unusual as well and required Acrow’s structure to stay in cantilever for 41 metres and at different slopes over the spans as it was pulled into place by cables across rollers.

“Acrow is proud to have been a part of this and many other important projects to restore historically significant bridges,” added Gordon Scott, Vice President Business Development and Operations, Acrow Canada. “Covered bridges are deeply entwined with the history of Québec and protecting and preserving these cultural icons for future generations is a significant accomplishment.”