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I-35W Mississippi River bridge facts for kids

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I35W Bridge
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.

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See also

Kids robot.svg In Spanish: Puente I-35W del río Misisipi para niños

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