The Colorado Department of Transportation (CDOT) redesigned the signal-free U.S. Highway 285/South Elk Creek Road intersection—better known as Shaffers Crossing—into an interchange incorporating an embankment supported by Pavestone Co. segmental retaining walls (SRWs) to enhance traffic flow and improve safety. The project won the SRW–Transportation Award in the 5th Annual HNA Hardscape Project Awards program (see page 39).
The redesign of Shaffers Crossing, five miles southwest of Conifer, required installation to occur at the bottom of a severe slope and above a creek, incorporating wall heights in excess of 53 ft. The project also needed to accommodate environment and site conditions, which included two large culverts to handle heavy spring flooding due to runoff, a wildlife passage to allow migration for the area's deer and elk, and a wall pattern and colors that complimented neighboring rock outcrops.
Pavestone Co.’s Anchor Diamond Pro Stone Cut system provided the multiple style stone sought out by CDOT. The company manufactured two color blends—antique pewter and tan brown—with block sizes of 7, 11, and 18-in. long, installed randomly to further blend in with the surroundings. Also, due to the harsh environmental conditions in Colorado, CDOT had increased the freeze/thaw performance requirements of SRW units in the right-of-way. The Diamond Pro units used at Shaffers Crossing met freeze/thaw tolerances of less than 1 percent material loss at 150 cycles or 60 cycles with 3 percent saline.
Furthermore, the original bid for the project called for import of select backfill. Instead, general contractor Hudick Excavating, Inc., Castle Rock, Colo., and wall contractor Bryan Miller Company of Denver used on-site excavated material that was crushed to specified dimensions. Year-round installation at an elevation of 9,000 ft. was facilitated through the use of the crushed granular fill, eliminating the costs of importing and exporting material, all awhile accelerating the project completion date. Phased construction began in September 2009, and the interchange was completed two years later.