I-35W Bridge Collapse - Week 56

Week 56 by Ivy Chang | September 28, 2010

NTSB will finish report by end of the year

The National Transportation Safety Board issued a statement that hinted at the cause of the I-35W Bridge failure. It said its final report will include the failure of gusset plates in specific areas of the bridge as one reason for the collapse on August 1, 2007.


On the south side of the Mississippi River, crews graded the slope from the abutment to the road and filled it with rocks while painting continued on the east side of the bridge.

Board investigators continue to conduct analytical work but said factual records are substantially complete and they are proceeding with drafting the final report to be presented for consideration at a public board meeting scheduled tentatively for November 13.

The report will contain conclusions, a probable cause, and safety recommendations aimed at preventing future accidents.

Concrete pour on main span is complete

Construction crews poured the last of the concrete for the main span of the I-35W Bridge and are waiting for it to cure. They’re now working on finishing touches – painting, installing signs, landscaping, and continuing to install and test traffic signals, lighting and the anti-icing system.

Most of the construction equipment has been removed from the bridge deck and roadways as the entire structure is near completion.

This week, crews continue to build the median barriers and install fencing on the mainline highway, paint lane stripes on the entrance and exit ramps at University Avenue, and grind the concrete surface of the northbound bridge to prepare for traffic. On the exit ramp from the southbound highway to Washington Avenue, landscaping began as a crew planted trees.

A painter sprayed paint under the bridge deck to complete the main span. Another crew began building the observation plaza around the piers on the north end of the bridge.

At the base of the piers, concrete pours began for the observation plazas on both sides of the Mississippi River. In addition, crews also are paving West River Parkway, Second Street Southeast and 14th Avenue South.

A smaller construction crew continues to work night shifts seven days a week on both sides of the bridge.

Sidewalk Superintendent Talk ends this week

The last Sidewalk Superintendent Talk on the Tenth Avenue Bridge will be on Saturday, September 6. Flatiron-Manson initiated the talks as part of its proposal to build the bridge. Since early November 2007, nearly 5,000 people participated in the weekly events, which provided an opportunity to learn about the I-35W Bridge construction from project managers.

Bike lanes on the west side of the Tenth Avenue Bridge will be closed, as usual, for this Sidewalk Superintendent Talk.