Pedestrian Bridge Lift

Problem:
Pedestrian bridge had to be lifted safely through high voltage lines and set into position across the tracks.

Solution:
The bridge was raised to an elevation of 80 and lowered carefully using tag lines to control swing.

Description:
Marino Crane was asked to provide a lifting solution to place a pedestrian bridge over the Metro-North Railroad at the new Fairfield Metro Center in Fairfield, CT. Site conditions and existing steel obstructions were a heavy influence on the layout of the crane. The Metro-North Railroad also imposed a 1.5 safety factor requirement for all lifts. In the end, the 500t Liebherr hydraulic crane was the only crane trailable in the available fleet that could complete the work. The crane was erected with 86 Main Boom at 84 degrees w/ 92 Luffer. The front of the carrier was driven beneath beams of an existing steel overpass to maximize clearance over the rear. The 60 long, 54,000lb bridge was picked at an 81 radius and raised to an elevation of about 80. The bridge was swung over de-energized high voltage lines and rotated using tag lines so the bridge ran parallel to the tracks. The bridge was lowered from the highest position until it cleared the lowest wires and then rotated again into its final position across the tracks.
The high voltage lines on the opposite side of the tracks remained active during the lift. To overcome this, the swing of the crane was limited and the piece was controlled by tag lines at both ends of the piece; the crane was also grounded as an added precaution. During the worst case swing, the stay cables on the luffing jib cleared the existing steel overpass by less than a foot. The lift was performed at 2 am while all four train lines were de-energized.