Tower cranes from Dawes Rigging & Crane Rental Inc., a member of the ALL Family of Companies, are dominating the Minneapolis skyline, and now several of them can be found in an unlikely location. Since January, three tower cranes from Dawes have been on site at the 3rd Avenue Bridge, which crosses the Mississippi River and connects downtown with the northeast part of the city.
“It’s the first time in my career that we’ve used tower cranes for bridge work,” said Ryan Harrison, branch manager of Dawes’ Madison, Wisconsin location. “I’ve seen it done in projects in Europe, and now we have one here.”
Bridge rehab work is often performed with a crane barge, but that was not feasible here. Due to the shape of the bridge—famous for its S-curve—and its location near Anthony Falls Spillway, it is not reachable by barge.
Using standard all-terrain or crawler cranes also was not an option. “There were load-bearing considerations,” Harrison said. “Cranes would only be able to be positioned on certain parts of the bridge and then only in specific orientations. It would have been limiting.”
So, general contractor Ames Construction hit on the idea of using tower cranes by attaching them to the bridge piers.
“They were looking for an option other than having a crane on the bridge deck,” said Harrison. “The idea was to design a foundation that could be integrated into an existing pier and support the load from a tower crane.”
The project’s engineers—Finley Engineering Group of Tallahassee, Florida—worked with engineers at Dawes’ sister company, ALL Tower Crane, to make the idea a reality. Across an engineering document exceeding 300 pages and representing several months’ collaboration, the teams came up with a workable solution. “It’s amazing what they were able to achieve,” said Harrison.
Three tower cranes went up on the bridge in January, with a fourth scheduled to be added in August. Piers two and three each support Potain MDT 368 tower cranes (that fourth crane, to be erected in Pier 4, will also be this model), while pier 5 has a Potain MDT 389. The 389, an updated version of the 368, was chosen for pier 5 due to its improved onboard work-site zoning system for working around overhead obstructions. Hook heights range from 72 ft to 120 ft. The taller heights normally associated with tower cranes are not needed in this case since the bridge is a horizontal rather than vertical structure.
From their strategic and well-anchored positions, the tower cranes will move a variety of construction materials across the bridge deck, where small rough-terrain cranes await to carry material throughout the project.
The 3rd Avenue Bridge is located just eight blocks from another attention-grabbing tower project from Dawes and ALL Tower Crane. At the corner of 11th Avenue and West River Parkway, work continues on the high rise called Eleven, which will eventually be the city’s tallest residential building.
“Driving down West River Parkway has become quite a calling card for us,” Harrison said. “It’s exceedingly rare to have a number of tower cranes servicing a spanning bridge like this. The location and accessibility challenges of the jobsite lent itself to this kind of craning. It’s a beautiful location that is part of downtown’s history … and for the next 15 months it’s home to a different kind of engineering miracle.”
Editor's Note: Scranton Gillette Communications and the SGC Infrastructure Group are not liable for the accuracy, efficacy and validity of the claims made in this piece. The views expressed in this content do not reflect the position of the Roads & Bridges' Editorial Team.