STH 29 south of Wausau required pavement replacement, and its bridges over the Wisconsin River and Business 51 needed redecking. The project widened the westbound (WB) bridges over the Wisconsin River and Business 51 and the eastbound (EB) bridge over Business 51 to accommodate additional lanes and traffic staging. The STH 29/Sunrise Drive overpass bridge deck had surface spalls and delaminations, requiring preventive maintenance to extend its service life. This bridge also needed to be raised on the north end to gain proper clearance for over-size-over-weight vehicles traveling on STH 29 under Sunrise Drive.
Design strategies predominantly addressed the pragmatic goals of extending the life of the bridges and in most cases widening them, as well as simplifying future maintenance to save money and minimize traffic interruptions, but Ayres’ designers also paid attention to aesthetic details to make sure the bridge widenings did not take on a tacked-on appearance. Scour countermeasures were incorporated to address scour issues at the Wisconsin River piers, and polymer overlays were placed on the Wisconsin River and Business 51 bridges.
Rethinking expansion joints: It was decided to remove the expansion joints in the middle of the Wisconsin River bridges and plate over the maintenance-prone joints in the girders. The way the bridges expand and contract due to temperature changes was modified by reworking the bearings so that the movement was accounted for at the ends of the bridges. The differences in bearing heights required special attention when producing a road profile to fit the bridge.
Strategy for adding lanes: Widening of the Business 51 bridges involved adding prestressed concrete girders adjacent to existing girders. Special design considerations were needed since the existing bridges were flared (wider at one end than the other). The girder type selected for the widening made use of the more readily available and less costly wide flange 54-inch-deep section.
Diverse structural design/construction challenges: The project entailed work over water from barges, grade separations over local roads, highways, and Canadian National Railway tracks; design of both concrete girders and steel girders; unique steel girder joint retrofits; piling and spread footing foundations; new substructure construction and widening of existing substructures; widening flared bridges; deck replacements done half at a time under traffic and replacements done at one time; bridge jacking; concrete deck overlay; steel girder repainting; temporary shoring on land; and cofferdams in 35 feet of water. An access road was included in the design to provide efficient access for construction materials and equipment to the tight working area between two sets of Canadian National Railway tracks and the Wisconsin River.
The pavement replacement from the Wisconsin River to Business 51 included replacing signs, completing pavement marking, and placing culverts as warranted.
The project included development of an environmental document (ER) covering the improvements in this project as well as improvements to be performed under the following future projects:
Structures and roadway for a new alignment of the STH 29 westbound to IH 39 southbound ramp for conversion to a right-off.
Intersection improvements at the Business 51/westbound STH 29 on/off ramp intersection.
Improvements to the STH 29 westbound on-ramp from Business 51 for conversion to a dual-lane ramp.
Improvements to the merge area of the westbound STH 29 to northbound IH 39 ramp.
An eastbound auxiliary lane from IH 39 to Business 51.
Widening the eastbound STH 29 bridge over the Wisconsin River.