July Project of the Month – CDOT Project ES1 2854-117 – Highway 285 and Shaffer’s Crossing
Wall Contractor: Bryan Miller Company, Inc. – Denver, Colorado
General Contractor: Hudick Excavating, Inc. – Castle Rock, Colorado
CDOT Project ES1 2854-117 is our Project of the Month for July 2010. While still a work in progress, over 20,000 of the required 66,000 sf have been installed since January with the balance scheduled for completion in late 2010/early 2011. The partially completed wall will eventually attain a height of 40’, with remaining walls nearly 60’ in height.
When the determination was made to expand Highway 285 at Shaffers Crossing, CDOT understood the existing site conditions would require massive retaining wall structures. At such a scale, aesthetics were crucial in not only the style of block but the color as well. The wall pattern and colors had to compliment the complexity of the existing rock outcrops which dot the area. Pavestone’s Anchor Diamond Pro Stone Cut System provided the multiple style stone CDOT was looking for. The 18”, 11”, 7” wide, multi piece pattern is split to provide a natural, rough-hewn texture which emulates the appearance of stone. Pavestone created multiple custom colors which are blended on site by the Bryan Miller Company, Inc. further complimenting the surrounding landscape.
Despite the aesthetic concerns, it was fully acknowledged the primary focus would be the variety of structural issues at the site. CDOT required a structurally stable, flexible and long term solution, requiring the block have a minimum compressive strength of 4500 psi.
Due to issues with other wall products, CDOT also requires wall material to have no more than 1% material loss after 150 freeze/thaw cycles, a crucial concern in the Rockies. Actual test results for the Diamond Pro show a total loss of less than .15%, with all tests easily passing the minimum requirement.
Coupled with the block elements, the project entails multiple semi loads of Mirafi geogrids, extreme blasting, excavation and thousands of trucks loads of backfill.