Costs emerge on bridge options
New cost estimates released last week show the costs for the two remaining options for the replacement of the Hastings bridge are closer than originally thought.
The Minnesota Department of Transportation announced last week it would include the single cable-supported bridge and single arch bridge in a request for proposals expected to go out in November.
According to MnDOT the cost of the cable bridge, in 2013 dollars, is $265.7 million. The cost of the arch bridge is $262.7 million, a difference of less than $3 million.
The least expensive of the three bridge options MnDOT studied most closely, the twin box girder bridge, has essentially been eliminated from consideration. There are, however, a few extenuating circumstances that could bring the box girder bridge back under consideration.
The twin concrete box girder bridge would have cost $234.9 million, according to MnDOT, about $30 million less than the two bridge types that are moving forward.
The city of Hastings, the State Historic Preservation Office, and Hastings Heritage Preservation Commission all rated the box girder bridge on the low end of their preferred bridge options.
The box girder bridge also had the least amount of support from the Visual Quality Team, which has worked for months on the bridge project and is made up of Hastings residents, city staff and elected officials.
Project Manager Steve Kordosky said the cost was the biggest sticking point internally at MnDOT when it was deciding what bridge types to carry forward. In the end, however, the box girder bridge was eliminated from consideration.
"This recommendation is consistent with MnDOT's strategic directions and demonstrates our commitment to innovation and developing context-sensitive solutions," MnDOT Commissioner Tom Sorel said in a news release.
New numbers for future maintenance costs were also released by MnDOT. It estimates the cable bridge would cost $8.5 million over 100 years to maintain, while the arch bridge would cost $10.5 million over the same time span. The box girder bridges would have cost $4.1 million to maintain for a century.
The timeline for construction of the cable and arch bridges is three to three-and-a-half years. The box girder bridge would take three-and-a-half to four years to build.
MnDOT will set a price cap for the bridge project, and ask contractors to submit bids under the price cap. It is hoped this will lead to a lower cost for the bridge.
"By allowing builders to consider multiple bridge types when developing proposals, the bidding process will become more competitive and innovative," according to MnDOT's news release.
If no contractors submit bids under the price cap, the box girder bridge may be considered again. Also, environmental work is continuing on the bridge site, and if something unexpected is discovered that would make the cable and arch bridges not feasible to build, the box girder could be considered.
The requests for proposals will go out in early November and will come back in March 2010. MnDOT is working toward having the bridge under a design-build contract by June 2010.
Mayor Paul Hicks was pleased with the decision and said he felt MnDOT worked with the city and residents and wants to build a bridge here that fits in with the community. He said he got the sense that those who made the decision about what bridge types will be included in the request for proposals understood Hastings' history of having unique bridges and took that into account.
"A lot of people in that room felt the sense of importance that this is a gateway to our city," he said.
District 57 Sen. Katie Sieben said she's glad MnDOT is using an innovative bidding process for the project and hopes it results in cost savings for taxpayers. She also said she was glad the arch and cable bridges moved forward.
"Either bridge design will reflect the unique characteristics of Hastings," she said.
Because both the cable-supported and arch bridges are single spans, they would be built directly to the west of the existing bridge, where traffic would remain until the new bridge is complete. Once traffic is shifted onto the new bridge, the current bridge would be torn down.