The Minnesota Dept. of Transpor­tation has reaffirmed its selection of a design-build team led by Longmont, Colo.-based Flatiron Constructors Inc. in joint venture with Seattle-based Manson Construction Co. to rebuild the collapsed Interstate 35W bridge. At the same time, on Oct. 8, officials unveiled the design for a 504-ft-long, precast-concrete segmental main span.

Also on the team now holding the $243-million contract is Orlando-based Johnson Bros. and Tallahassee, Fla.-based Figg Bridge Engineers Inc. as lead designer. At a press briefing, Flatiron-Manson project manager Peter Sanderson said the team hopes to start work on the 1,216-ft-long, 10-lane crossing over the Mississippi River, dubbed the St. Anthony Falls Bridge, by Nov. 1. Completion is scheduled for Dec. 24, 2008. “Our top priority is safety, both throughout construction and during the entire life of the bridge,” he said. MnDOT documents say potential late fines are $3,500 a day with a $27-million cap.

The bridge, designed for a 100-year life, will have four 70-ft-tall piers supported on drilled shafts into bedrock. It will be over 180 ft wide, allowing room for potential bus-rapid-transit or light rail in addition to five lanes in each direction.

Main-span precast segments will be placed by a barge-mounted crane, while 330-ft-long, 260-ft-long and 121-ft long cast-in place concrete spans, all prestressed and post-tensioned, will be erected on falsework. The proposal also in­cludes a sensor and monitoring system and possible monumental markers. Figg President and CEO Linda Figg emphasized that there will be no fracture-critical members in the redundant design.

MDOT	MDOT
MDOT
One of two types of piers will be chosen in a workshop later this month, but I-35W bridge in Minnesota will feature a precast segmental main span carrying 10 lanes of traffic.

A one-day design charette workshop will be scheduled this month in which community participants may choose from two pier options: that pier columns taper from 30 ft at the top and bottom to 11 ft in the center to match the curvature of the main span, or columns with straighter piers and recesses to create texture. Figg says the first option would include bearings between the piers and superstructure, while the piers in the second option would be monolithic. Participants also may choose between a white and sandstone coloring for the overall bridge, types of railings and LED lights.

MnDOT also released bid documents and an 18-page report rebutting claims by the losing bidders that the agency had “misdirected” them in the process. The report, submitted by MnDOT’s chief procurement officer and contracts manager, concludes, among other things, that MnDOT followed the “design/build selection process as prescribed in state law,” did not show predisposition for concrete over steel and that Flatiron’s top score did not depend on the public-relations component.

The two protesting teams are reviewing the technical scores MnDOT assigned them. “[They] have been requesting the scoring data and proposals to examine for weeks,” says Dean Thomson, a lawyer representing Ames/Lunda and C.S. McCrossan. “We just got the information last night [Oct. 8].”

Protesters and industry observers have criticized the state transportation department for signing the contract immediately upon its award, “allowing no time for the protesters, public or legislature to ex­amine these proposals,” he says. If the losing teams decide to pursue the case, the next step would be to file a complaint in court.