The Iowa Illinois Memorial Bridges carry eastbound and westbound I-74 over the Mississippi River. The nearly identical twin suspension bridges consist of twelve spans which include three-span suspension units, two three-span pony truss units, and three deck truss spans. The westbound span was constructed in 1935 and the eastbound span was constructed in 1960.
The inspections were performed in accordance with NBIS and included a hands-on inspection of fracture critical members (FCM) and a routine inspection of the remaining portions of the structures. M&M utilized standard and technical climbing techniques to access most bridge elements without restrictions to vehicular traffic. The continuous pony truss top chords were inspected with two-day traffic control assistance.
During this inspection, Iowa DOT was constructing replacement structures immediately upstream of the existing I-74 alignment, which were opened to traffic in the winter of 2020/2021.
Having performed both the original design of these bridges and the final design for the replacement structures, M&M was pleased to perform these inspection services to assure continued safety for the traveling public during this transition.
|Suspended Spans Lengths
|Total Bridge Lengths
|Lanes on Structures