I-35W Minnesota River bridge

The I-35W Minnesota River Bridge connects the counties of Hennepin and Dakota, and the cities of Bloomington and Burnsville, over the Minnesota River. The bridge has eight lanes, four lanes in each direction. Inner lanes are MnPass HOV lanes, and a walking/bicycling path is located on the east side of the northbound span. The bridge is 1,361 feet (415 m) long, and 170 feet (52 m) wide.

History

Prior to the Interstate Highway System being built, the key highway route into the south side of Minneapolis was US Highway 65. US-65 crossed the Minnesota River on a narrow 2-lane bridge. In the late 1950s, MN-DOT began to upgrade US-65 to a 4-lane highway in the south metro area. The 4-lane would run from MN-5 (current I-494) down to MN-13 in Burnsville along Lyndale Avenue.

As the MN-65 project was underway, Congress passed the Interstate Highway Act. As a result, the MN-65 project was recast as Interstate I-35W in the metro area. As part of the project, a large bridge would be needed to span the Minnesota River. To keep traffic moving year around, the bridge would have to be above the 100 year flood plain and span the entire flood plain. The plan that was developed was to build a long earthen causeway through the flood plain in Burnsville (on the south side of the river), then construct a nearly 1,500 foot long steel girder bridge over the main river channel. A small fill would be needed on the north side of the bridge, followed by a large cut to help reduce the grade heading over the river bluff on the north side of the river.

In 1960, a new bridge was built by the Minnesota Highway Department. It was a seven-lane steel girder bridge.<ref name=":0">{{Cite|url=http://www.johnweeks.com/river_minnesota/pages/mnA07.html|title=I-35W Bridge, Bloomington, MN|website=www.johnweeks.com|access-date=2020-03-06}}</ref>

At this point the old bridge was closed permanently and demolished.

Approaches to the former bridge had issues with flooding, with a 1965 flood putting the causeway just south of the bridge completely underwater. After this, the roadway was rebuilt to raise it a few feet, and has not flooded since, though temporary dikes have needed to be built along the causeway on several occasions.

When this bridge was opened in 1960, I-35W extended south only as far as MN-13. Locals called this the bridge to nowhere. As the rest of I-35W in the south metro area came online throughout the 1960s, traffic picked up on I-35W. A major shopping center was developed in Burnsville, which lead to housing, light industry, and service businesses locating south of the river. By 1980, traffic jams at the I-35W bridge were becoming a serious problem. By the 1980s congestion had become a severe problem on the bridge, In order to address this problem, the bridge was widened. The piers were made wider, and two additional lanes were installed on the bridge. This would allow for a future where the bridge would have 3 traffic lanes in each direction.

In 1989, new lanes were opened as high-occupancy vehicle lanes when the Minnesota Department of Transportation (MnDOT) expanded the north approach to carry additional traffic.

In February 1987, the body of a man last seen three months prior sitting alone in a car on the Interstate Hwy. 35W bridge over the Minnesota River was found downstream in the Mississippi River.

In September 1988, a man jumped (or fell) into the Minnesota River from the Interstate Hwy. 35W bridge.

In March 1989, there was discussion of easing traffic congestion by opening two previously closed lanes leading to the bridge. William Crawford, the district engineer in charge of the project, believed that there would be subsoil problems at the north end of the bridge if the lanes were opened. In response, then Governor Rudy Perpich ordered a soil study at the north end of the Interstate Hwy. 35W bridge over the Minnesota River to see if the two previously barricaded lanes could be opened to traffic. There was concern the $15 million investment to build the expanded approaches would be lost since, according to a Department of Transportation March 1989 statement, "the current bridge will be replaced eventually by a higher bridge."

Shortly after the bridge project was completed in 1984, it was discovered that there was a sub-soil problem near the bridge approaches. This problem would prevent the new lanes from being opened to traffic. The sub-soil problem caused the expansion problem to languish of several years. Finally, in 1990, Governor Rudy Perpich ordered MN-DOT to do an analysis of the problem in order for the legislature to get a handle on how big the problem was. The resulting study found that the problem turned out to be a minor issue. The sub-soil problem was fixed in the early 1990s.

In the mid 1990s, the highway median was removed through Bloomington, and two lanes were added to the center of the highway. With this, the additional lanes were opened on the bridge over the Minnesota River.

MnPass lanes were added in 2009, with both leftmost lane in both directions being eliminated to allow for such. Additionally, the southbound direction was re-stripped with four southbound traffic lanes, and the drainage pipes were rebuilt.

As part of a $120 million project, a completely new bridge was constructed to replace the 1960 one, which had reached the end of its useful service life and was considered not built to last. Work on the emplacement started in 2018, and it was opened by 2019. At this point, all traffic was routed onto the new bridge and the old one was demolished and replaced. Work as completed in 2021.