Two Medicine River Bridge, Browning, Montana

SEGMENTS, WINTER 2012, VOL. 57

US Hwy. 2 crosses over the Tow Medicine River just outside of East Glacier Park in northwest Montana. The existing 70 year old steel deck truss carrying the highway will soon be replaced by a cast-in-place concrete segmental box girder using the balanced cantilever method of construction. Spanning the deep, steeply sloped gorge, the deck of the new structure will be nearly 200 feet above the channel below. This bridge will include a single-cell box girder with spans of 290 ft., 520 ft. and 350 ft. with three 120 ft. spans of precast MTS-72 girders for the east approach with a total length of 1,520 ft (Fig. 15). The structure will accommodate a 12 ft. lane and an 8 ft. shoulder in each direction with a 6 ft. sidewalk on the north side.

Construction began in October 2011 and good progress was made installing the 6 ft. and 8 ft. diameter drilled shafts over 80 ft. deep and socketted into rock during extended good weather through mid-November (Figs. 16, 17 and 18). The steep slopes made access to the work sites challenging with limited room for staging near the piers. After a short work suspension during the winter, the foundations were completed and the substructure units took shape, giving recent rise to the construction of the first pier table at Pier 2. Cantilever construction is expected to begin by early October and the structure is expected to be opened to traffic by late fall of 2012.