(Minnesota) — A simple concrete bridge design has been chosen by Minnesota Department of Transportation (MnDot) to replace the I-35W steel lattice arch bridge over the Mississippi, which collapsed at the beginning of August.
The winning design will include multiple levels of structural redundancy and will be constructed using high performance concrete for superior durability.
A sensor and monitoring system will also be built into the bridge to allow for monitoring of the structure’s condition through its lifetime.
The Flatiron-Manson and FIGG design was chosen as it was considered to best address MnDot’s concerns over structural durability and robustness raised by the collapse.
The new bridge will combine twin, five-lane spans and the flexibility to build a light rail transit line and a pedestrian bridge underneath in the future. The central span will be made from precast concrete units made locally and delivered to the bridge by barge.
Formal complaints from two losing bidders that the bidding process was flawed were lodged but later thrown out after an investigation. Both submitted cheaper bids, with a shorter programme and have alleged that concrete was preferred over a steel but not specified in the competition.
But officials concluded that nothing in the bidding process was “arbitrary or capricious,” as the protesters claimed.
By: Jessica Rowson