RBA replaced the original three-span, 210-foot-long, prestressed concrete bridge with a 192-foot-long, simple span, steel beam and composite concrete deck bridge, working with subconsultants for surveying and mapping, environmental issues and highway design. The riparian environment, including adjacent state- and federally-regulated wetlands, had to be protected. Our design solution was to remove half of the existing bridge lengthwise, maintain traffic on the remaining half, and construct the entire new bridge immediately adjacent. In addition to addressing the stated concerns, this allowed for the roadway alignment to be improved by eliminating a broken-back curve and providing spiral curve transitions. Design features of the new bridge include a single span to avoid the scour concerns associated with river piers, horizontally-curved weathering steel plate girders, and a jointless abutment at the fixed end to reduce the number of deck joints. Our work was coordinated with the Adirondack Park Agency, the New York State Department of Environmental Conservation, the U.S. Army Corps of Engineers, local government officials, and local residents. Accordingly, our design included relocation of the Hudson River gaging station, creation of wetlands to compensate for those that were impacted, improving the intersection immediately west of the bridge, and moving overhead utility lines to a new location below the bridge deck.
