ST. PAUL, Minn. – A soaring yet simple concrete bridge set atop 70-foot, land-based piers will replace the collapsed Interstate 35W bridge over the Mississippi River.
The design was made public Monday by the Minnesota Department of Transportation and the companies it hired to build the replacement bridge, which is expected to open by the end of next year.
The goal was to design a bridge that blends the modern feel of the nearby Guthrie Theatre and the more traditional Stone Arch Bridge adjacent to it, said Linda Figg, president of the FIGG Bridge Engineers design firm.
The state has pushed an aggressive timetable to replace the steel bridge, which was a major link to northern Minneapolis and its suburbs when it collapsed Aug. 1, killing 13 people and injuring about 100.
The eight-lane bridge, which crumpled within seconds during evening rush hour, once carried 141,000 vehicles a day. The cause of the collapse is under investigation.
The new bridge combines twin, five-lane spans and will include highly durable concrete, built-in sensors for monitoring its structural integrity and multiple backup systems that were absent in the collapsed steel bridge.
It also will be built to accommodate a light rail transit line in the future and a possible suspension bridge underneath for pedestrian traffic. The plan also calls for parks with observation decks below the bridge.
"It is a sculptural bridge where the form and the function work with proportion and elegance to create a model for other bridges in America," Figg said.
A full-day community forum will be held later this month where selected participants can vote on the appearance of the support piers, a memorial to the fallen bridge and other aesthetic features.
A ceremonial groundbreaking is likely to be held next week. But the heavy work probably won't start until November, said Peter Sanderson, the project manager for Flatiron Constructors Inc.
Flatiron and Manson Construction Co., will build it. The contract requires completion by Christmas Eve 2008, although the builders can earn multimillion-dollar bonuses for finishing sooner.
The unveiling came a few hours after another state agency recommended rejection of a protest by two losing bidders.
C.S. McCrossan Construction and a joint team of Ames Construction and Lunda Construction argued that the bidding process was flawed. They submitted a cheaper bid, with a shorter timetable, than the winning bid of nearly $234 million.
The losing bidders alleged that DOT preferred a concrete bridge over a steel bridge, but didn't say so in its specifications.
Department of Administration contracts manager Betsy Hayes and chief procurement officer Kent Allin concluded that nothing in the bidding process was "arbitrary or capricious," as the protesters claimed.