I-35W Bridge Collapse - Week 40

Week 40 by Ivy Chang | September 28, 2010

Victims of the I-35W bridge collapse and others are asking why Minnesota transportation officials didn’t follow news of the Interstate 90 bridge over Ohio’s Grand River when it nearly collapsed 12 years ago. At that time, investigators determined what was considered a unique cause for the bridge to buckle: undersized and corroded gusset plates that were too small to support traffic and a heavier load of construction vehicles and equipment parked on the bridge.

In the 1990s, when the bridge buckled, experts considered the incident an anomaly, said an engineer who helped investigate the I-90 bridge.

The Ohio incident was not widely publicized, and officials at the Minnesota Department of Transportation can’t say what the agency knew about that incident.

Ohio bridge information may not have reached other states

Lawyers for many victims of the I-35W bridge are looking at records and decisions made by states based on knowledge of the Ohio bridge. According to Ohio documents, the incident led to changes in Ohio, but federal findings on the design of gusset plates on Interstate 90 never received the nationwide alert that followed the I-35W bridge collapse.

Following the buckle, the Ohio Department of Transportation shared its bridge information which became a regular part of training for Ohio bridge inspectors, but a spokesman said he didn’t know whether federal or state officials shared the information with other departments of Transportation.

Crews pour concrete on road beds at the bridge’s south approach.

A MnDOT representative from the Bridge Office was sent to the International Bridge Conference in Pittsburgh in 1997 but did not go to the Ohio bridge presentation. When asked about the event, the representative said he attended presentations on new construction methods and topics that were more relevant to Minnesota.

Concrete pours continue on approach spans

Crews finished pouring concrete on half of the northbound approach span on May 8 and half of the southbound approach on May 11. This week, they continue to pour concrete for the remaining northbound road bed on the south approach span.

The barge with Big Ben (red crane) is positioned on the river’s north side to help lift pre-cast segments for the main span. At left is the north approach span.

At the casting yard, 96 pre-cast segments for the main span have been built; crews plan to build another nine by May 17. As of May 11, 14 segments have been delivered to Bohemian Flats for finishing work. The delivery occurs between 7 a.m. and 7 p.m. seven days a week.

At the north side, another crew is pouring concrete for the bottoms and sides of the approach spans. Noise and street closings have delayed and rerouted traffic around the bridge.

The pedestrian tunnel on the south side under the approach span has been completed and covered. Beginning May 20, crews will begin demolishing the road bed between the south approach span and the casting yard for reconstruction. Work will be carried out 24 hours a day and may last up to four weeks.

Construction of the Second Street bridge continues with increasing road closings on both sides of the river for material and segment hauling and utility relocation.

Jon Chiglo, project manager from MnDOT, appears on television news every week to provide progress reports on the bridge construction.