Preserving Architectural History with the West Montrose Covered Bridge
- Communications Entuitive
- Oct 8
- 5 min read
Going Behind the Project on a Heritage Icon in West Montrose, Ontario
A heritage icon, a vital link, and a complex rehabilitation rooted in community.
Tucked into the rural landscape of West Montrose, Ontario, two hours west of Toronto, stands the West Montrose Covered Bridge, affectionately known as “The Kissing Bridge.” This heritage structure is the last remaining wood-covered bridge in Ontario to still carry vehicular traffic and serves as an essential lifeline for the local Mennonite community.
Built in 1881 from locally sourced timber, the bridge connects the north and south halves of West Montrose over the Grand River. For many in the local Mennonite community who still travel by horse-drawn carriage, it’s the safest way to reach their church. Without the bridge, they would be forced to navigate onto a nearby highway with traffic that travels as fast as 100 km/h.
After more than 140 years of service, and several rounds of undocumented repairs, the Region of Waterloo decided to rehabilitate this important bridge, retaining Entuitive and Moses Structural Engineers as the bridge engineering consultants.
We sat down with Andrew Lehan, Associate, to discuss this complex heritage rehabilitation project.
Thanks so much for your time, Andrew, can you tell us about this project and its unique challenges?
Andrew: Absolutely. This bridge is very much beloved by the local community and its residents. They even have a residents’ association known as the BridgeKeepers, who act as advocates for the bridge. So, we wanted to make sure we undertook the rehabilitation in a way that upheld its heritage status and meaning for the community.
The bridge is a two-span, through-truss covered bridge structure. It carries a single lane of mixed-use pedestrian and vehicular traffic across the Grand River. Both spans are about 28.9 metres long.
The bridge has undergone many undocumented repairs. Of note is that steel Bailey trusses were added inside the bridge in 1965 to augment its capacity. They are covered by white-coloured wood paneling to protect them against salt spray.
How did you deal with the undocumented repairs?
Andrew: Our first step was to assess the condition of the bridge. Entuitive was retained to carry out a comprehensive assessment and design process, which included a detailed visual inspection and non-destructive testing, structural evaluation to determine the existing load-carrying capacity, development and comparison of rehabilitation options, an environmental assessment and public consultation, and, finally, preliminary and detailed design.
From our inspection, we learned that the trusses were built from Eastern Hemlock, Red Pine, and White Pine, all native species of the area. Many members, like the top chords and most diagonals, were in good to fair shape. Others, particularly the end diagonals and bottom chords, were suffering from significant decay. The floor system also showed signs of deterioration. A substantial intervention was thus needed.
What did your inspection reveal about the structure of the bridge?
Andrew: Structurally, the bridge is fascinating. It features a two-span through truss configuration with single-plane timber trusses along each side. Each side acts as a truss-within-a-truss-within-a-truss, a layered design combining a king post truss at midspan, nested within a queen post truss, which is in turn set within a larger queen post truss.
Some have called this configuration a Hybrid Howe truss. The members are constructed from solid-sawn heavy timbers, while the truss vertical elements consist of paired steel hanger rods.
To understand how much live load the bridge could safely carry, we conducted a two-phase structural analysis, starting with 2D modeling and moving to a more detailed 3D model to capture lateral behaviour. Our evaluation examined loads from 3 tonnes up to 15 tonnes, helping us pinpoint the thresholds, or “fuse points”, beyond which additional reinforcement would be necessary.
How did you approach rehabilitation after your inspection?
Andrew: We worked closely with the owner, community stakeholders, and heritage specialists to develop and compare three rehabilitation alternatives. The chosen approach involved removing the steel Bailey trusses and strengthening the existing wood trusses in kind. This allowed the original timber structure to once again act as the primary load-carrying system., something it had not done since the mid-1960s when the steel Bailey trusses were added.
The work included replacing the decayed bottom chords and end diagonals, and selectively reinforcing existing members. Where full-length solid sawn timbers could not be sourced, we introduced spliced connections, a practical concession to heritage requirements, which did not permit engineered wood products like glulam.
What were some key challenges and the solutions you deployed?
Vehicular and Pedestrian Loads
Andrew: One of the more nuanced challenges on the project was establishing the appropriate design live load. The Canadian Highway Bridge Design Code mandates bridges be designed for a CL-625 truck, which is a 62.5 tonne vehicle. But for West Montrose, this would have been excessive. Instead, we collaborated with the owner to settle on a 10-tonne design load, striking a balance between safety against overweight vehicles and heritage preservation.
Pedestrian loading was another consideration. The code requires a 4.0 kPa uniform loading, but our site-specific assessment showed that such levels weren’t realistic for this bridge’s usage. We refined the loading to account for situations like a tour group photo, applying the full pedestrian load over a 2.5m length of deck instead of the full length.
We also evaluated the unique live load contribution of horse-drawn carriages, particularly on Sunday mornings when convoys cross the bridge en route to church. Our studies showed that a 2.4 kPa uniform load would adequately capture this regular event.
Wind, Snow, and Flood Loading
Andrew: Beyond vehicular and pedestrian loads, we also accounted for wind, snow, and flood loading, each requiring a site-specific approach.
Because of its large frontal area and more squat aspect ratio, the bridge acts more like a sign board than a typical steel or concrete girder bridge. By adjusting the drag coefficient from the standard 2.0 to 1.3, we were able to reduce horizontal wind forces by 35%.
Site-specific snow loading had already been calculated previously by others following a site-specific study, allowing us to bypass overly conservative code-mandated values. We incorporated snow loading into the bridge code load combinations, using best practices from the National Building Code of Canada.
Finally, a hydraulic analysis revealed that the bridge would become partially inundated during the Regional Flood (a 100–150-year return event). Raising the structure wasn’t an option due to road geometry constraints, so we designed for the resulting vertical and lateral forces, including uplift significant enough to cause stress reversal in the trusses, which meant that many compression-only wood connections would experience tension. These connections had to be reinforced accordingly.
What was your favourite part of the project?
Andrew: Perhaps the most important aspect of this project was working with a community that holds this bridge close to heart. For residents of West Montrose, especially its Mennonite population, this is not just a structure, it’s a symbol of identity, history, and continuity.
We’re proud to have played a role in preserving this iconic piece of Ontario’s engineering heritage, while ensuring it continues to serve its community safely and sustainably for generations to come.
Thank you so much for talking to us about this unique heritage bridge, Andrew.
To learn more about this project, reach out to Andrew Lehan to learn more.