The rectangular spreader beam and synthetic roundslings in basket-hitches minimized forces on the pressure-sensitive concrete pipe walls and joints.
outriggers be at least 20 feet from the seawall, and that each one be supported by a 6-footby-12-foot-by-8-inch steel outrigger pad to reduce maximum ground-bearing pressure to about 4,500 PSF.
Using that ground-support arrangement, the big Liebherr crane made all six lifts from one location on 139 feet of boom and at radii to 85 feet.
Rectangular Spreader, Synthetic Roundslings
The trident placement project relies on two cranes, both supplied by Bay Crane Midwest.
All of the tridents and pieces of the Cross T section that
connects them were loaded onto a barge by the previously mentioned 550-U. S.-ton Liebherr LTM 1450-8.1 all-terrain crane.
In the near future, they will be lowered into their final positions on the lake bottom by a bargemounted 100-U. S.-ton capacity Manitowoc 222 lattice-boom crawler crane.
Part of Dearborn’ s challenge in designing the load rigging was making sure the same rigging setups could be used by both cranes.
The other two rigging challenges were that the centers of gravity of the pieces had been calculated but not verified, so
12 • 800-247-2000 • December 2025