Southern Parkway; Washington Dam Road to 4300 West
- Core Competencies:
The Southern Parkway, at final build out, will be a four-lane, divided highway designed to serve the area from St. George to Hurricane in Washington County, Utah. This project was Phase 4 of 5 and had a distance of approximately 4 miles.
Two major rock cuts and one major soil cut were a significant part of the project. One rock cut was a maximum of 125 feet tall and approximately 850 feet long and the second rock cut through Navajo Sandstone was a maximum of 110 feet tall and approximately 3200 feet long. The total quantity of rock excavation utilizing blasting was 478,350 cubic yards. The major soil cut had a maximum cut slope height of approximately 50 feet and consisted of predominantly granular soil and cemented granular soil. Over 300,000 cubic yards of total roadway excavation was required on the project. Paving consisted of placing about 24,800 tons of HMA (hot mix asphalt concrete) and 8,100 tons of SMA (stone matrix asphalt concrete).
Structures within this contract included four bridges and pipe culverts. Bridges were constructed on the eastbound (EB) and westbound (WB) lanes at the Long Valley / Washington Dam Road and the Sand Hollow interchanges. The bridges are single span structures with integral raised abutments and slope paving. Reinforced concrete pipe was used for culverts at drainage crossings, with corrugated steel pipe used for the 72 inch pipe culvert at the east end of Warner Valley.
This project was constructed in an environmentally sensitive area known for desert tortoise habitat which is on the Federal Threatened Status List. All employees were required to attend training about the desert tortoise prior to performing work on this project. In addition, the site had Archeological and Paleontological sensitive areas that required special excavation requirements. W. W. Clyde worked with archeologists, Indian Tribes, and Paleontologists, with no impact to the project schedule. In the archeological areas, three feet had to be excavated in six inch lifts, which was inspected by archeologists after each excavated lift. This process lasted one and a half weeks resulting in the discovery of two houses and one human remain which were removed to an area museum. W. W. Clyde also exposed areas for the Paleontologists, which they investigated after each lift of excavation, and assisted in removing 10 truckloads of material to a local area museum where students from the University of Utah processed the material.