OCCI was contracted to build a new, double-track bridge, 2,550 feet long and 180 feet above the Des Moines River in Boone, Iowa to replace the Kate Shelly Bridge, built in 1901. The new bridge by the numbers includes: 23,350 cubic yards of concrete, 1,660 tons of reinforcing steel, 275,700 cubic yards of earthwork, 56 drilled shafts (8’ and 9’ diameter) 75’ deep, 600 prestressed precast deck panels (poured onsite by OCCI), twelve 70’ steel girders (42 tons each), and forty 100’ steel spans (93 tons each). The steel girders were set using an OCCI derived top-down method with an overhead lift-n-carry gantry system running along a box beam track affixed to the concrete tower pier caps. This top-down system eliminated the challenge of benching into the 2:1 slope on the river bank, as well as mitigated the risk of flood waters.
Drilled Shafts; Substructure; Drilled Shafts; Steel Erection; Steel Assembly; Temporary Bridge; Specialized Falsework Install and Design; Span Launch
