Michigan Avenue Bascule Lift Bridge Restoration
When the Michigan Avenue bascule bridge leaf accidentally lifted out of control, it rotated so violently that it tore itself off its main supports and dropped to the bottom of the counter-weight pit. RRJ investigated the cause of this freak accident and assisted in restoring the bridge with the primary task of lifting and positioning the 3.2 million pound bridge and repairing the parts damaged by accident.
RRJ conducted a condition survey and computer modeling of the concrete pit walls, floor, and caissons and analyzed them for the massive jack reactions so that the jacking operation could be performed safely. Repair designs were required of the main bearing beams and anchorage system along with designs for various temporary steel brackets used to reposition the bridge. Hydraulic jacking was used to restore the bridge to its original position.