Winslow Crane Service Co. was hired to set a 150 ft. long pedestrian bridge in Colorado Springs, Colorado. A new housing development was breaking ground and the bridge was an integral part of a trail system that would connect various parts of the development. Designed to span a small drainage, the bridge would also carry water via an integrated pipe system residing under the pedestrian platform.
Due to unstable ground conditions in the drainage, the Winslow Crane team crafted a lift plan that would use a combination of their 500-ton Liebherr 1400-7.1 and 450-ton Grove GMK6400 all-terrain cranes.
Each crane would be set up on opposite sides of the drainage to make the tandem lift.
The lift plan called for the Liebherr 1400-7.1 to be configured with 135 ft. of boom and 286,600 lbs. of counterweight at a radius of 104 ft. The 450-ton Grove GMK6400 was configured with 114 ft. of boom and 297,600 lbs. of counterweight at a radius of 104 ft.
Once each crane was set up on their individual pads, the 105,000 lb. bridge would be passed from the Liebherr 1400-7.1 to the Grove GMK6400 with the use of a tri-bar (passing triangle).
The tri-bar allows the leading crane to pass the load to the awaiting crane in an in-air transition over the drainage. Once the lead crane was able to resume its share of the load, the bridge was placed carefully on its abutments and was ready for installation.