Timely rehabilitation of Baxter Bridge reinstates reliable transportation linking BC’s Okanagan region

The iconic Baxter Bridge connects communities across the Shuswap River, southeast of Enderby, BC in the Okanagan Shuswap District. Constructed in the 1950's, the 91 metre long bridge includes two, 30 metre, Howe Truss spans and accommodates single-lane, alternating traffic. The bridge serves several small communities, providing access for emergency vehicles, school buses, and industry. In addition, in the summer, local and international tourists are drawn to this area for the recreational water activities.

Over the past 20 years, with aging and continual deterioration, the bridge has undergone a series of repairs, resulting in intermittent bridge closures that have impacted local residents. The 70+ year old structure is nearing the end of its service life and the BC Ministry of Transportation and Infrastructure has scheduled the bridge for replacement with a modern and reliable structure.

In 2021, the Ministry retained Associated Engineering to conduct a detailed condition assessment of the bridge that identified extensive deterioration of multiple bridge components. For public safety, these deficiencies necessitated downrating of the bridge capacity by 50%, to a maximum gross vehicle weight of 25 tonnes, due to the deteriorating pile condition requiring critical repairs.

While necessary, this downrating significantly impacted the local community, reducing direct community access by large fire trucks, other emergency response vehicles, and milk trucks. The crossing is the primary route used by trucks delivering fresh unpasteurized milk from four Shuswap dairy farms to the milk processing facility located in Kamloops, about 120 kilometres away. Without bridge access, the detour would result in an additional 2.5 hours of travel time, and have a detrimental impact on their businesses.

Associated Engineering was tasked to design a short-term repair for the bridge to reinstate the original, posted load limit, while the preparatory activities for a future bridge replacement were undertaken. Project Manager, Julien Henley, tells us, "Closing the bridge for even a few months to facilitate extensive repairs was not an option; we needed to keep the bridge open for primary emergency services, local businesses, and school buses. Moreover, the Shuswap area has experienced several wildfires, and closing the bridge to emergency responders could have devastating consequences to the safety of the local communities."

The team mobilized quickly after the Ministry’s notification to proceed, completing the design of the rehabilitation works within six weeks; construction was completed 16 weeks later. Julien says, "We worked closely with the Ministry Representative to support mobilization of the maintenance contractor and worked with a contractor to source and fabricate material while completing the design. Our team also completed emergency permitting. During construction, our team's agile response addressed design changes in the field."

The bridge's rehabilitation preserved its iconic Howe Truss style

Structural Engineer, Natalya Kucherenko, tells us, "Our design improves the bridge's capacity and safety, and could be implemented using intermittent closures. We developed an innovative, portal-frame, strengthening solution and completed substructure repairs to the piles and pile caps using small unpropelled barges. This approach minimized the need to work from the bridge deck and significantly reduced traffic disruptions."

Strengthening using the U-frame allowed us to eliminate the portal bracing. Natalya says, "This repair solution addressed truss stability and prevented further deterioration of the truss system. Due to the effectiveness of the design, the Ministry is now considering adopting this solution to rehabilitate similar, aging, Howe Truss bridges in the province."

Julien says, "The safety and water rescue crew installed a bespoke portable floating dock to facilitate works access from under the bridge. The construction process went smoothly, strictly following all safety procedures and environmental protection measures, including full-time environmental monitoring."

To reinstate pile capacity, the construction team installed segmented, grouted, steel jackets around the existing, decayed, timber piles. The crew manually installed the segmented jackets around the pier, ensuring absolute watertightness to the assembled jacket, to prevent concrete grout from leaking, and protect the sensitive salmon habitat while salmon were spawning in the Shuswap River.

Works were carried out in small packages to shorten road closure durations. Julien shared, "Planning of the works was extremely complicated, but with comprehensive constructability and traffic management plans, and, working collaboratively with the contractor, we were able to limit closures, allow intermittent vehicle traffic, and minimize back-up along Trinity Valley Road. We also coordinated road closures to avoid impacting school buses - kids were never late for school." Scheduled opening times were communicated in advance through the province’s DriveBC app, posted locally, and shown on changeable message signs on-site.

After completion of the works, the dock was donated to the neighbouring property and now provides public access to the river. The dock has become a local attraction for tourists and the local community, creating another legacy for the community.

The carbon footprint of the project was lowered by sourcing steel and timber from local suppliers, using a local workforce for traffic control, and utilizing local storage provided by the community. The local community appreciated the efforts of the design and construction team, which put the community’s needs and requirements at the forefront of the design considerations. Local residents were so pleased with traffic measures during construction that they regularly brought doughnuts and coffee to the construction team!

Constructed since the 1840s, today, timber Howe Truss type bridges like the Baxter Bridge have gradually been replaced by modern structures. As a result of this transition, such bridges have become increasingly rare, and greatly coveted by filmmakers drawn to their antique and historical allure. Over time, the Baxter Bridge has had its fair share of moments in the cinematic spotlight, with appearances in Hollywood productions like "Blackway" (2015) and "Tomorrowland" (2015).

The successful rehabilitation efforts have significantly prolonged the lifespan of this local landmark. This character bridge will continue to serve residents and tourists until a modern steel and concrete replacement is erected. The sentiments surrounding this historic bridge run strong; the Ministry is now inclined to preserve the original Baxter Bridge for future pedestrian and cyclist use, when the replacement bridge is constructed.

In 2023, the Baxter Bridge Rehabilitation project received an Award of Excellence in the Projects Under $2.5 Million category at the ACEC-BC Awards for Engineering Excellence.

Key personnel involved on the project include Julien Henley, Natalya Kucherenko, Dale Harrison, Emma McGowan, Steven Root, Alfred Kao, Dave Hayward, and Bob Smith.