35W Bridge Construction Vibration - Minneapolis, MN



Minneapolis, Minnesota


University of Minnesota

General Contractor:

Flatiron Construction Corp.

In August 2007, the 35W bridge over the Mississippi River in Minneapolis, MN collapsed. This event resulted in 13 deaths and the news shook the engineering community in ways that are still being felt. The University of Minnesota’s Tandem Linear Accelerator Building is located adjacent to the bridge and housed three MRIs used for research at the time of the collapse.

Engineers from ESI were called to provide vibration monitoring services due to the recovery and demolition phases of the bridge. ESI's vibration monitoring then continued inside the building during drilling, pile driving, and excavation.

We used our vibration monitoring system together with a camera to capture extreme events that could have threatened the many pieces of sensitive equipment within the building and to alert the University and contractor.

Browse the project photo gallery below!