A New Tied Arch to Replace a Rural Mississippi River Crossing

The US 52 bridge over the Mississippi River provides a crucial transportation link for the region, connecting Savanna, Illinois to Sabula, Iowa with the nearest alternate Mississippi River crossing located almost 32 kilometers to the south and is now rapidly approaching the end of its useful life. The proposed replacement consists of 12 spans totalling 748 meters from a causeway in the middle of the Upper Mississippi River Wildlife and Fish Refuge in the Mississippi River on the Iowa side to the high bluffs of the Mississippi Palisades in Illinois. The 166.4-meter main span steel tied-arch over the navigation channel incorporates a floating deck system and redundancy design concepts while simplifying details. The construction of deep cofferdams in the river is eliminated in favour of large diameter drilled shafts foundations with waterline footings, the first use of this construction method by the Illinois DOT.