I-35W Bridge Collapse - Week 33

Week 33 by Ivy Chang | September 28, 2010

The National Transportation Safety Board released photographs of the I-35W bridge from 2003 that showed at least two bent gusset plates located in the bridge’s connecting beams. NTSB investigators believe the gusset plates were among the first points of failure in the collapse in addition to the plate design that was one-quarter inch too thin.

One photo dated June 10, 2003 shows slight bowing in two gusset plates at U-10 west, a marking system for the plates underneath the bridge deck. A second photo dated June 12, 2003 shows one gusset plate at U-10 east bending in the same direction as the U-10 west connection.

Inspection records of the bridge did not mention anyone ever repairing the out-of-plane bending since the photographs were taken. NTSB is working to confirm the origin of the photos which were part of the more than 100 pages of new information from its investigation.

No comment as investigation continues

The NTSB has not commented on bowing of the bridge before it collapsed and will continue to investigate the gusset plates as one cause of the collapse.

Lawyers representing survivors also are scrutinizing the NTSB information and photos. Two lawyers representing over 200 victims and their families want to know when MnDOT first discovered gusset plate deformations and what it did about the problem.

MnDOT added a layer of concrete to the deck in 1977 and installed concrete barriers in 1998 which increased weight on the bridge. NTSB estimated that over 99 tons of sand and gravel had been piled on the roadway over the weakest points when the bridge collapsed.

Abutments and piers rise on both sides of the Mississippi River

The steel supports are stretching from Abutment 1, on the south side of the Mississippi River and Abutment 5, on the north side. Crews are lining rebar on the forms resting on top of the structures and began pouring concrete for the first span this week.

The temporary forms for Piers 2 and 3 have been removed as concrete cured. Construction of gabion walls on the south side of the bridge has begun. These are walls that will be built around the steel supports that stretch from Abutment 1. Temporary support structures for the bridge’s side spans continue to extend toward the piers on both sides of the river.

Crews also are relocating utilities and widening the I-35W roadway south of the bridge. Hammering and back-up alarms are noticeable as workers remove old asphalt, curbs and gutters and as they load trucks.

A 600-ton capacity ringer crane arrived at the area known as Bohemian Flats to help lift needed materials on top of the piers and, later, will help lift segments that make up the main span. As of this week, 26 segments out of 120 needed segments have been poured.

Street traffic has been rerouted for the utility relocation and allowing trucks to access various construction sites. The Tenth Avenue bike lane is closed on Saturdays from 11 a.m. to noon.

Compensation funds go unclaimed

Organizations that have received funds to compensate survivors of the bridge collapse are puzzled that half of the money available has not been claimed.

The Minneapolis Foundation has at least $1.2 million in a special fund that provided about half of that money to survivors. Money came from a variety of organizations that held fundraisers or donated from their funds.

A $1 million state emergency relief fund established in November gave away $154,000 even though the state doubled the amount an individual can claim. A federal loan program for small businesses affected by the bridge collapse awarded only two loans with few inquiries about the program.

Administrators of these programs think many victims are going through their insurance companies, don’t know enough about the new programs, or are dealing with emotional issues that can’t be resolved with available funds.

Congressional Medal of Honor presented to Miller

Matthew Miller, the summer construction worker from Progressive Contractors Inc., who rescued at least eight people when the I-35W bridge collapsed, was honored on March 25 at the Tomb of the Unknown Soldier at Arlington National Cemetery. Former Secretary of State Colin Powell presented the Congressional Medal of Honor Society’s Above & Beyond Citizen Honors to Miller and 34 other recipients.

After the ceremony, Miller also appeared on the Today show in New York and said he’s not sure he will work in construction this summer because he becomes nervous on bridges.