I-35W Mississippi River bridge facts for kids

The I-35W bridge in 2006, before it collapsed.

The I-35W Mississippi River bridge was a large bridge in Minneapolis, Minnesota. It was made of steel and had eight lanes for cars. This bridge opened in 1967 and was very busy. Over 140,000 vehicles used it every day, making it the third busiest bridge in Minnesota.

On August 1, 2007, during the evening rush hour, the bridge suddenly fell down. This terrible event, known as the I-35W bridge collapse, killed 13 people. The U.S. National Transportation Safety Board (NTSB) investigated why it happened. They found that a problem with the bridge's design likely caused the collapse. A steel plate, called a gusset plate, was too thin and ripped. Also, extra weight from ongoing construction work on the bridge contributed to the failure. The bridge fell into the Mississippi River. A new bridge, the I-35W Saint Anthony Falls Bridge, was built in its place. It opened in September 2008 and has 10 lanes.

About the I-35W Bridge

The I-35W Mississippi River bridge was an important part of the Interstate 35W highway. It helped many people travel across the Mississippi River every day. The bridge was built using a design called a steel arch bridge. It was a key connection for traffic in and around Minneapolis.

What Caused the Bridge to Collapse?

Investigators from the National Transportation Safety Board (NTSB) worked hard to find out why the bridge fell. They discovered that some of the steel plates, called gusset plates, were not strong enough. These plates connect different parts of the bridge's structure. The NTSB found that some of these plates were too thin.

The bridge was also undergoing repairs at the time of the collapse. Heavy construction materials and equipment were placed on the bridge. This extra weight, combined with the weak gusset plates, put too much stress on the structure. The plates ripped, leading to the entire bridge falling down.

Building a New Bridge

After the collapse, it was important to build a new bridge quickly. The new bridge, called the I-35W Saint Anthony Falls Bridge, was built in just over a year. It opened in September 2008. The new bridge is wider, with 10 lanes, and includes modern safety features. It was designed to be much stronger and safer than the old bridge.

Images for kids

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  The south end of the I-35W bridge, seen from West River Parkway.

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  The I-35W bridge (center left) near the 10th Avenue Bridge (center right) in 2004.

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  The bridge seen from below in 2006.

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  Security camera images show the collapse in animation, looking north.

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  Cars that were on the bridge when it collapsed remained in the wreckage during the investigation.

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  Mayor R. T. Rybak looking at the collapsed bridge.

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  Ninety-three people were rescued from the collapsed bridge. Minneapolis Fire Department boats helped many people from the Mississippi River.

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  United States Navy divers helping with the recovery operation from a United States Army Corps of Engineers barge.

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  A helicopter and airboat near the 10th Avenue Bridge during the rescue.

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  Col. Michael Chesney, Transportation Secretary Mary Peters, and Hennepin County Sheriff Richard Stanek.

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  Donald C. Winter, former Secretary of the Navy, views the I-35W bridge collapse site. Minnesota Governor Tim Pawlenty is to the left.

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  FBI evidence team and Hennepin County sheriff's deputies using sonar.

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  This image from the National Transportation Safety Board shows a fracture in a gusset plate, which was key to the bridge's collapse.

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  Bowed gusset plates seen in June 2003.

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  A closure sign on Interstate 35W after the collapse.

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  A section of the collapsed bridge.

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  People watching from the Stone Arch Bridge.

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  The disaster site was used by TV crews. Contessa Brewer is shown here reporting for MSNBC.

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  A view of the pillars of the replacement Saint Anthony Falls bridge.

See also

In Spanish: Puente I-35W del río Misisipi para niños