18. Ambassador Bridge Grid Replacement-1


Location: US Plaza to US Tower 1, Detroit
Contractor: Toebe Construction
Supplier: Hercules Concrete
Engineer: Modjeski and Masters
Owner: Detroit International Bridge Company

Being the #1 international border crossing in North America since its creation in 1929, constant maintenance is required on the Ambassador bridge to support a wide variety and steady flow of traffic. One of the recent maintenance tasks was grid replacement on the bridge deck. Phase 1 of this replacement took place in 2020 on the US side, from the plaza to US Tower 1, requiring roughly 13,500 square yards of 8-inch-thick grid deck concrete. Concrete was placed through pump feeding and then screeded. Starting in July and finishing in December, both Toebe and Hercules had to make necessary adjustments to complete the project in all weather and temperature conditions.

Hercules Concrete was presented with multiple challenges during this project. Being new to the game, they had to design and test a new mix from scratch, capable of supporting 7,000 psi with no historical data, all while achieving the targets set forth by the engineer. Dialing in the air content and slump of the concrete was also a challenge due to the plant being in close proximity to the project (directly under the bridge). The finished product is a stellar section of grid replacement that will support traffic flow on this important bridge for years to come.