PCA's Tenth Biennial Bridge Awards

Concrete International, Dec 2006

University Avenue Arched Pier Bridge over I-74, Peoria, IL-Using a precast concrete tied-arch pier to span the Dry Run Creek flume and support the bridge in a two-span configuration proved to be an excellent alternative in a situation where a conventional design was not possible. The bridge's aesthetic elements were very significant to the design. The decorative concrete bridge bollards were precast and shipped to the site for installation. A limestone formliner was used on the walls of the vaulted abutments to create a hand-laid stone appearance. The parapets were built with a smooth formliner using self-consolidating concrete.

Project credits: Illinois Department of Transportation, owner; Alfred Benesch & Co., engineer; Walsh Construction Co., contractor; Construction Materials, concrete supplier; and Prestressed Engineering Corp., precaster.

Four Bears Bridge, New Town, ND-This 4500 ft (1370 m) precast segmental bridge, North Dakota's first concrete segmental bridge and the only crossing of Lake Sakakawea, was erected using the balanced cantilever method. A precast concrete cofferdam with sloping faces was developed to reduce the impact of ice forces while simplifying the pile driving operation. The cofferdam also served as a stay-inplace form for the cast-in-place concrete pile cap foundation for the pier. Several design features addressed the need for durability and minimum maintenance, including high-performance concrete, longitudinal and transverse post-tensioning of the deck, elimination of the deck blockouts for tendon anchorages, a continuous jointless deck, and 3/4 in. (19 mm) integral concrete wearing surface. The context-sensitive design recognized local Native American culture and history with tribal symbols on the box girder web walls and pedestrian walkway.

Project credits: North Dakota Department of Transportation, owner; FIGG and Kardmas, Lee & Jackson, engineers; Fru-Con (now Bilfinger Gerger Civil Inc.), contractor; and Watford City Ready Mix, concrete supplier.

Noyo River Bridge, Fort Bragg, CA-All of the challenges faced by the designers can be attributed to site constraints, though these limitations contributed to the unique design features of this bridge. The threespan four-lane cast-in-place concrete post-tensioned box girder bridge is 874 ft (258 m) long with a main span of 327 ft (100 m). Structural challenges included use of mass concrete, high seismic activity with soil liquefaction, and staged construction because the alignment of the new bridge was the same as the old one. The builders and designers needed to be sensitive to environmental issues, and the view of the harbor and the jetty below the bridge had to be preserved.

Project credits: California Department of Transportation, owner, engineer, and architect; MCM Construction Inc., contractor; and Granite Construction Co. and Baxman Gravel Co., Inc., concrete suppliers.

County Road 453 over Battleground Creek Bridge, Coupland, TX-Maintaining a short construction time was the driving force behind the design of this 60 ft (18 m) singlespan bridge. Because of channel hydraulics, the structure depth was limited to 24 in. (600 mm). Engineers at the Texas Department of Transportation focused on minimizing the number of beams, using simple beam connections, and minimizing the use of cast-in-place concrete. Building on the existing standard precast/ prestressed slab beams, a new beam shape was developed. The side-by-side T-beams were connected to each other along the longitudinal V-shaped joint by welding a connector rod to steel plates embedded in flanges of the beams. A conventional bridge at this site would have taken 6 months to build; the new T-beam bridge took only 6 weeks.