Acrow’s Ingenious Detour Bridge Keeping Michigan Moving
In the bustling transport corridors of Michigan, where commercial hauliers and everyday commuters share the same arteries, bridge replacement projects can cause major disruption.
Recognising this, the Michigan Department of Transportation (MDOT) turned to a proven solution to keep US-131 traffic flowing during the replacement of two ageing bridges near Kalamazoo, a temporary detour bridge designed and supplied by international bridge engineering leader Acrow.
A Strategic North-South Lifeline
US-131 is a vital north-south corridor in Michigan, funnelling a high volume of commercial and non-commercial vehicles and connecting communities to the Interstate 94 interchange. The bridges spanning KL Avenue and the Amtrak rail lines had reached the end of their service lives, prompting MDOT to opt for full replacement rather than costly, short-term repairs.
While traffic below the structures could be rerouted, maintaining the full capacity of US-131 during construction was non-negotiable. The challenge lay in doing so within an extremely limited build area, all while ensuring zero disruption to high-speed passenger rail services and avoiding any risk to rail infrastructure.
From Proposal to Baseline Requirement
Early in the planning phase, MDOT considered a detour bridge but faced concerns over the confined assembly and installation space. Acrow’s reputation for delivering high-quality modular bridging solutions in tight timeframes gave them the edge. Their proposal, backed by technical expertise, quality certifications and a solid track record, convinced MDOT to make the detour bridge a baseline requirement in the project tender.
The collaboration between MDOT, Acrow and other stakeholders was critical. Together, they devised a plan to erect the bridge within the narrow median strip — just 8 to 10 feet from live traffic on each side.
Engineering the Detour Solution
The chosen solution, an Acrow 700XS® modular steel bridge, stretches 350 feet (106.68m) in two spans — 200 feet (60.96m) and 150 feet (45.72m). With a 30-foot (9.15m) two-lane width and an asphalt overlay deck surface, it can comfortably handle the heavy daily traffic load.
Two Acrow 700XS® Towers, each around 30 feet (9.15m) high, act as intermediate piers. The structure was assembled in the median before being installed via a full cantilever launch — a method that minimised disruption to both road and rail operations.
Northbound traffic switched to the detour bridge in mid-March, allowing work on the first bridge to commence. By mid-July, northbound vehicles were back on the newly built structure, with southbound traffic shifting onto the detour. The temporary bridge will remain in service until late October 2025, ensuring smooth flow until both replacement bridges are complete.
Meeting Tight Deadlines in Tight Spaces
Abbey Smith, Acrow’s Business Development Manager for the Great Lakes Region, summed up the project’s success: “Acrow’s rapidly installed bridge was the perfect solution for this project, owing to the extremely limited build area and short timeframe required. With many years of experience designing detour bridges for highway upgrades and near active rail lines, Acrow has a thorough understanding of the unique challenges of these projects.”
The confined site and proximity to high-speed rail required precise planning and execution. The cantilever launch technique allowed installation without encroaching on the railway, safeguarding schedules and infrastructure.
Minimising Community and Economic Impact
Eugene Sobecki, Director of National Sales & Military Business Development at Acrow, emphasised the wider benefits: “In addition to enhanced work zone safety, detour bridges keep residents safe by enabling construction to continue without re-routing traffic through local community streets. They also mitigate impacts to the local economy and help keep projects on or ahead of schedule.”
Keeping US-131 traffic at full capacity has prevented congestion on alternative routes, minimised local disruption, and maintained the efficiency of a key freight and commuter link.
Addressing Ageing Infrastructure
Across the United States, thousands of bridges are approaching or past their intended service life. The American Society of Civil Engineers’ 2021 Infrastructure Report Card graded US bridges at a “C”, noting over 46,000 in poor condition. Michigan is no exception, with a significant backlog of structures needing repair or replacement.
Temporary modular bridges like Acrow’s 700XS® series provide a strategic advantage. They enable essential works without the delays and safety risks that come with extensive detours through residential or secondary road networks.
Acrow’s Global Reach and Expertise
Acrow has been delivering modular steel bridging solutions for more than 70 years, with applications ranging from permanent and temporary civilian use to military and emergency deployments. The company has completed projects in over 150 countries across Africa, Asia, the Americas, Europe and the Middle East.
Their bridges are valued for their durability, versatility, and ability to be rapidly deployed in challenging environments, qualities that made the US-131 detour project a success story in maintaining mobility during infrastructure renewal.
A Model for Future Projects
The US-131 project sets a benchmark for how infrastructure agencies can tackle major replacement works without sacrificing traffic flow. By integrating temporary bridging into the construction plan from the outset, MDOT avoided the costly delays and community frustrations often associated with such projects.
With the pressure mounting to replace ageing infrastructure across the US, modular detour solutions like Acrow’s will likely become an increasingly common feature of the nation’s roadworks toolkit.
Building the Future Without Stopping the Present
As Michigan drivers cruise over the temporary detour bridge, many may be unaware of the complex engineering and logistics that made their uninterrupted journey possible. Yet for MDOT and Acrow, the project demonstrates how strategic planning and proven technology can deliver infrastructure upgrades without bringing traffic to a standstill.
In an era where keeping people and goods moving is as critical as the works themselves, this project stands as a shining example of how to build for the future without halting the present.
