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Last reviewed October 2022

Minnesota Issue Guide
Minneapolis Interstate 35W Bridge Collapse

This guide is compiled by staff at the Minnesota Legislative Reference Library on a topic of interest to state legislators. It introduces the topic and points to sources for further research. It is not intended to be exhaustive.

Timeline  Internet Resources  Articles  Books and Reports

Shortly after 6 pm on August 1, 2007, the Interstate 35W bridge over the Mississippi River near downtown Minneapolis was loaded with rush hour traffic creeping through an ongoing construction project.  Without warning, the bridge collapsed, taking with it 111 vehicles. Thirteen people died and 145 were injured.

The National Transportation Safety Board ultimately determined that the probable cause of the collapse of the I-35W bridge “was the inadequate load capacity, due to a design error . . . of the gusset plates at the U10 nodes, which failed under a combination of (1) substantial increases in the weight of the bridge, which resulted from previous bridge modifications, and (2) the traffic and concentrated construction loads on the bridge on the day of the collapse.”

A replacement bridge was designed and constructed on an accelerated schedule and opened on September 18, 2008, not long after the first anniversary of the collapse.

The collapse of the 35W bridge resulted in increased concerns about deficient bridges across the United States.  In Minnesota, citizens and government officials alike sought access to MnDOT bridge inspection reports, Federal Highway Administration documents, and other records related to the history, maintenance, and safety of the 35W bridge – and all other bridges in the state. This guide pulls together many of those reports and links to materials that record the State of Minnesota’s response to the tragic collapse and its efforts to quickly replace that vital link over the Mississippi River.

This chronology outlines some of the significant events regarding the I-35W Bridge collapse and the efforts to build a new bridge:

August 1, 2007: Shortly after 6 pm, the I-35W Bridge collapses with 111 motor vehicles on it at the time.

August 4, 2007: Mn/DOT issues a request for qualifications for a Design Build Contract for the I-35W Bridge replacement project. Congress authorizes about $250 million to rebuild the 35W bridge. 

August 14, 2007: The Minnesota Legislature quickly established a  Joint Committee to Investigate the Bridge Collapse comprised of sixteen legislators from both the House and Senate transportation committees.  The Committee was charged with conducting a comprehensive review of decisions made by MnDOT pertinent to the collapse. 

August 20, 2007: The body of the 13th and final victim of the I-35W Bridge collapse is recovered from the Mississippi River.

August 23, 2007: MnDOT releases the request for proposal for the new bridge over the Mississippi.

September 11, 2007: The Minnesota Legislature holds a one day special session; legislation passed includes several provisions related to the bridge collapse (see Laws of Minnesota 2007, 1st Special Session, chapter 2).

September 14, 2007: MnDOT receives technical proposals from four companies: Ames/Lunda, C.S. McCrossan, Flatiron/Manson and Walsh Construction/American Bridge.

September 18, 2007: MnDOT receives financial proposals.

October 5, 2007: City of Minneapolis passes resolution that grants approval of MnDOTs proposed bridge layout.

October 8, 2007: MnDOT awards new bridge contract to Flatiron/Manson.

October 15, 2007: Transportation Contingent Advisory Group gives MnDOT permission to spend an additional $60 million through February 2008. This amount is short of the $195 million requested.

October 16, 2007: MnDOT is sued over selection of winning bidder. The lawsuit alleges that the bidding process unfairly favored Flatiron/Manson. Suit requests that bridge construction be halted. (Sayer and Phillippi vs Minnesota Department of Transportation; Case No. 62-CV-07-3425)

October 31, 2007: Judge rejects restraining order that would halt bridge construction. (Sayer and Phillippi vs Minnesota Department of Transportation; Case No. 62-CV-07-3425)

November 1, 2007: Actual construction of new bridge begins.

November 29, 2007: Governor Pawlenty and legislators announce the creation of "I-35W Emergency Hardship Relief Fund." This fund will provide $1 million in financial assistance to the victims of the 35W bridge collapse and their families. Victims and their families will be eligible for up to $10,000 in lost wages.

December 19, 2007: Minnesota Legislature's Joint Committee to Investigate the Bridge Collapse announces it has authorized the spending of up to $500,000 to the law firm Gray Plant Moody for an investigation into MnDOT and the I-35W Bridge collapse. The report is due in May 2008.

January 11, 2008: The National Transportation Safety Board's (NTSB) on-going investigation uncovers an error in the original design process that resulted in undersized gusset plates on some of Bridge 9340's main trusses. On January 15, 2008, the board issues Safety Recommendation H-08-1, dealing with load capacity calculations for non-load-path-redundant steel truss bridges in the United States. These findings were released in the Federal Highway Administration's interim report, Adequacy of the U10 and L11 Gusset Plate Designs for the Minnesota Bridge No. 9340 (I-35W Over the Mississippi River).

February 19, 2008: The Office of the Legislative Auditor releases an updated analysis, State Highways and Bridges, of their 1997 report, Highway Spending.

March 5, 2008: The NTSB issues Structural Investigation Group Chairman Factual Report 08-015 (available in print at TG25.M6 S77 2008). On March 17, 2008, a NTSB update states that excess construction weight was placed above the earlier-reported too-thin gusset plates.

May 8, 2008: Governor Pawlenty signs a $38 million package to compensate bridge victims for their injuries and losses.

May 21, 2008: The Joint Committee to Investigate the Bridge Collapse releases their report, Investigative Report to Joint Committee to Investigate the I-35W Bridge Collapse.

September 18, 2008: The new bridge opens.

November 14, 2008: The National Transportation Safety Board (NTSB) issues their report: Collapse of I-35W Highway Bridge Minneapolis, Minnesota, August 1, 2007.

November 18, 2008: MnDOT issues their response to the NTSB report.

August 23, 2010: URS Corporation agrees to pay $52.4 million to I-35W bridge collapse victims.

August 1, 2011: The 35W Bridge Remembrance Garden, located near Gold Medal Park, was unveiled by Gov. Mark Dayton and Minneapolis Mayor R.T. Rybak.

Significant Internet Resources

Minnesota Department of Transportation (MnDOT)

  • Interstate 35W St. Anthony Falls Bridge
  • In-depth information about the I-35W bridge (bridge 9340) and the 2007 collapse is available by contacting MnDOT's Office of Chief Counsel: 651-366-4799.

Minnesota Legislature

Joint House Transportation Finance Division and Senate Transportation Budget and Policy Division Committee

Joint Committee to Investigate the Bridge Collapse

Legislative History

  • On August 4, 2007 both the United States House and Senate authorized about $250 million to rebuild the 35W bridge in H.R. 3311. The law was signed by the President George W. Bush on August 6, 2007 (see P.L. 110-56).
  • On September 11, 2007, the Minnesota Legislature held a special session. Several I-35W provisions were included in Laws of Minnesota 2007, 1st Special Session, chapter 2, article 2, including $2 million provided for state matching funds needed to receive federal disaster assistance and a prohibition for insurance companies to state or imply that a policyholder filing a no-fault motor vehicle insurance claim related to the bridge collapse could result in non-renewal, cancellation, or premium increase.
  • On May 8, 2008, Governor Pawlenty signed a $38 million package to compensate bridge victims for their injuries and losses in Laws of Minnesota 2008, chapter 288.

Emergency Declarations

  • Executive Order declaring a peacetime emergency (Gov. Tim Pawlenty). The link includes the 30-day extension of the executive order by the Executive Council of the State of Minnesota.
  • Presidential Emergency Declaration was issued by President George W. Bush in a letter to Governor Tim Pawlenty.

Minnesota Historical Society

I-35W Bridge Collapse - MNopedia entry

Federal Government

National Transportation Safety Board (NTSB)

NTSB Docket ID Number: HWY07MH024 - August 1, 2007, Minneapolis, Minnesota - Contains list of NTSB documents associated with the bridge collapse investigation.


Significant Articles

(articles in reverse chronological order)

Bickal, Jim, and Sara Porter.  "Reporting, Memories From the I-35W bridge Collapse."  Minnesota Public Radio, August 1, 2017.

Bierschbach, Brianna.  "What is the Legacy of the 35W Bridge Collapse on Minnesota Politics and Policy?MinnPost, August 1, 2017.

Bakst, Brian.  "Since I-35W, State Has More Eyes and Sharper Focus on Bridges."  Minnesota Public Radio, July 31, 2017.

Adriaens, Emily. "2007 Special Session Fiscal Summary of Disaster Relief."  Money Matters (Minnesota House of Representatives, Fiscal Analysis Department), October 2007, p. 1-6.

"Aging Infrastructure: Is Neglected Maintenance Putting Americans in Danger?" CQ Researcher, September 28, 2007, p. 793-816.

Cook, Mike. "Disaster Relief Package Enacted."  Session Weekly, September 12, 2007, p. 1-2.

Significant Books and Reports

Adequacy of the U10 and L11 Gusset Plate Designs for the Minnesota Bridge No. 9340 (I-35W Over the Mississippi River). Washington, DC: Federal Highway Administration, Turner-Fairbank Highway Research Center, 2008. (TG25.M6 H65 2008)

Ballarini, Roberto, and Taichiro Okazaki. The Infamous Gusset Plates. Minneapolis: University of Minnesota [?], 2009. (TG25.M6 B35 2009)

Bridging the Gap: Restoring and Rebuilding the Nation's Bridges. American Association of State Highway and Transportation Officials, 2008. (TG23 .B75 2008)

Bridging the Mississippi: The New I-35W Bridge: Minneapolis, Minnesota. (Dedication Day 2008 Commemorative Book) FIGG, 2008. (TG25.M6 B75 2008)

Collapse of I-35W Highway Bridge Minneapolis, Minnesota, August 1, 2007. Washington DC: National Transportation Safety Report, 2008. (TG25.M6 I253 2008)

Economic Impacts of the I-35W Bridge Collapse. St. Paul: Minnesota Dept. of Employment and Economic Development, Minnesota Dept. of Transportation, 2009? (TG25.M6 E36 2009)

The End of the Road: Challenges of Funding Minnesota's Local Road and Bridge Network. St. Paul, Minn.: Bonestroo, 2007. (HE356.M6 E53 2007)

Fatigue Evaluation and Redundancy Analysis: Bridge 9340, I-35W Over Mississippi River. (Draft report). Minneapolis: URS Corporation, 2006. (TG25.M6 F38 2006)

Fracture Critical Bridge Inspection: In-Depth Report, Bridge #9340 (Squirt Bridge): I-35W Over the Mississippi River at Minneapolis, MN. St. Paul: Minnesota Dept. of Transportation, 2006. (TG25.M6 F85 2006)

Hartgen, David T. and Ravi K. Karanam. 17th Annual Report on the Performance of State Highway Systems (1984-2006). Los Angeles: Reason Foundation, 2008. (TE220 .H37 2008)

Highway Spending: a Program Evaluation Report. St. Paul: Office of the Legislative Auditor, 1997. (HE355 .H56 1997 ) Note: In August 2007, the Joint Legislative Committee to Investigate Bridge Collapse asked the Office of the Legislative Auditor to update this report. The resulting report, State Highways and Bridges, was published in February 2008.

I-35W Bridge Collapse and Repsonse: Minneapolis, Minnesota. U.S. Fire Administration/Technical Report Series, FEMA, 2008. (TG25.M6 S73 2008)

I-35W Bridge over the Mississippi River Collapse Investigation: Bridge no. 9340: Minneapolis, Minnesota. (Consultants report prepared by Wiss, Janney, Elstner Associates.) Oakdale, Minnesota: Minnesota Department of Transportation Bridge Office, 2008. (TG25.M6 I 254 2008)

Infrastructure 2008: A Competitive Advantage. Washington D.C.: Urban Land Institute, 2008. (HC79.C3 I54 2008)

Investigative Report to Joint Committee to Investigate the I-35W Bridge Collapse. Minneapolis: Gray Plant Moody, 2008. (TG25.M6 I25 2008)

Kirk, Robert S. and William J. Mallett. Highway Bridges: Conditions and the Federal/State Role. Washington, DC: Congressional Research Service, 2007.

LePatner, Barry B. Too Big to Fail: America's Failing Infrastructure and the Way Forward. New York: Foster Publishing, 2010. (HE206.2 .L47 2010) This book addresses the I-35 bridge collapse in detail.

Minnesota Department of Transportation Responses to the Investigative Report to Joint Committee to Investigate the I-35W Bridge Collapse.   Minnesota Department of Transportation, 2008. (TG25.M6 I252 2008)

MnDOT's Response to National Transportation Safety Board Recommendations. St. Paul: Minnesota Dept. of Transportation, November 18, 2008. (TG25.M6 I2532 2008)

National Bridge Inspection Standards Compliance Review Report. St. Paul: Minnesota Dept. of Transportation, Office of Bridges and Structures, 2008. (TG315 .N38 2008)

Nunnally, Patrick.  The City, the River, the Bridge: Before and After the Minneapolis Bridge Collapse.  Minneapolis: University of Minnesota Press, 2011.  (HN80.M6 C57 2011)

O'Connell, Heather M., Robert J. Dexter, and Paul Bergson. Fatigue Evaluation of the Deck Truss of Bridge 9340. St. Paul: Minnesota Dept. of Transportation, Office of Research Services, 2001. (TG25.M6 O36 2001)

Report on Expenditure of I-35W Bridge Special Compensation Appropriations. St. Paul: Minnesota Management & Budget, 2009. (HJ7599 .R47 2009) (Mandated by: 2008 Minn. Laws Chap. 288 Sec. 6 Subd. 5)

Road User Cost Due to Unavailability of Interstate 35W Mississippi River Crossing at Minneapolis, Minnesota. St. Paul: Minnesota Dept. of Transportation, 2007. (TG25.M6 R63 2007)

Stambaugh, Hollis and Harold Cohen. I-35W Bridge Collapse and Response, Minneapolis, Minnesota, August 1, 2007. Emmitsburg, Md.: Federal Emergency Management Agency, Department of Homeland Security, United States Fire Administration, National Fire Programs Division, 2008. (TG25.M6 S73 2008)

State Highways and Bridges. St. Paul: Office of the Legislative Auditor, 2008 [includes 2010 update]. (HE355.H562 2008) The Legislative Auditor was requested to update their 1997 report, Highway Spending, shortly after the 35W bridge collapsed.

Truss Bridges: Trunk Highway Bridges and Local Bridges. St. Paul: Minnesota Dept. of Transportation, 2008. (TG24.M6 T78 2008)

Wattson, Peter. Compensating Victims of Bridge Collapses Outside Minnesota. St. Paul: Senate Counsel, 2007. (TG470.W38 2007)

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