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New I-35W Bridge Tells All

Construction on the I-35 bridge over the past year has led to "one of the most instrumented bridges in the nation" said Jon Chiglo, project manger for MnDOT, for the Pioneer Press. Once traffic files over the bridge in the next week, sensors embedded in the concrete at various points will feed the Minnesota Department of Transportation with information from how the bridge is managing the flow of traffic to when the steel faces the risk of corrosion.

The new technology included in the design will eliminate the required biannual inspections that have given enough time for steel to corrode and bearings to dislodge between maintenance checks on the old 35W bridge.

"We'll have a whole history of it, versus having snapshots at a set period of time," said Tom DeHaven, project engineer and design coordinator for Tallahassee, Fla.-based Figg Engineering, the company that provided the design.

The bridge features over 300 sensors on the deck that will detect whether chloride from anti-icing chemicals are becoming a threat to the steel reinforcements. Information collected by MnDOT and the University of Minnesota through fiber-optic cables will also determine how the concrete is holding up through strain gauges and measure movement in the expansion joints and bearings.

MPR reported Gov. Tim Pawlenty and other officials will appear on Monday to announce the specific opening time of the bridge this week. As much as $27 million will be spent in bonus money for finishing the bridge ahead of schedule.