For Southern California skiers, snowboarders and mountain bikers U.S. Highway 395 serves as the main route to and from Mammoth Mountain, the tallest ski resort in the state.
Because a significant portion of Highway 395 has always been a two-lane highway with no median separation, head-on collisions often occur due to passing attempts.
This summer steps were taken to change that, as two separate construction projects — focused on expanding and upgrading a combined 26 mi. (41.8 km) of Highway 395 — were underway.
The $28.2 million Blackrock Four-Lane Project focused on upgrading and expanding 14 mi. (22.5 km) of two-lane highway, in between the cities of Independence and Big Pine, into a four-lane expressway.
The $39.2 million Manzanar/Independence Four-Lane Project includes similar upgrading work along 12 mi. (19 km) of Highway 395, and also involves the construction of a four-lane, all-paved road within the city of Independence.
The Manzanar project is slated for a fall 2010 completion, while the Blackrock project wrapped up, on schedule, in early August, according to Susan Lent, public information officer of Caltrans District 9.
Located between the towns of Independence and Big Pine, the Blackrock project began in October 2007.
The project’s first stage involved the construction of two new lanes west of the existing lanes.
“Our biggest challenge on this job was rock,” said Mark Hegbloom, project manager for general contactor Skanska USA Civil West.
Hegbloom explained that a 14H blade and 623-finish scraper pulled up a significant amount of rock while trying to make grade.
As a result, the subgrade area could not be plated, as the project required the export of rock.
“The nearest material site was approximately 50 miles away,” Lent said, explaining that in order to reduce project costs, Caltrans and the Bureau of Land Management worked together to make a nearby material site, for exporting and importing, available for Skanska.
During new lane construction, rock cuts were pre-ripped with a single shank D10T, and Cat 365 excavators and Cat 740 rock trucks were used to move the larger, bonier excavation material. Additionally, 657 scrapers were utilized to move the closer, less bony excavation.
“We were able to eliminate some blasting on the job by using the D10T dozer, with a single shank ripper, to get through some of our rock cuts,” Hegbloom said, adding that anywhere from 15 to 100 workers were onsite each day.
Paving operations were performed with a Skanska-owned Cedar Rapids paver and Cat CB634 rollers.
Aside from rock, another project challenge involved weather, specifically wind.
Because of the often strong, high desert wind gusts, one 4,000-gal. (15,142 L) water truck was utilized nearly full-time for dust control.
Following new lane construction, both northbound and southbound traffic was placed on the new lanes so Skanska, who was the lowest qualified bidder on the project, could reconstruct the existing lanes and perform some AC grind/overlay work.
Once all upgrade construction was complete, southbound traffic was transitioned onto the reconstructed lanes and northbound traffic began using the two new lanes.
In total, 405,000 cu. yds. (310,000 cu m) of roadway excavation, 44,470 cu. yds. (34,000 cu m) of Class 2 aggregate base, 148,800 tons (135,000 t) of asphalt, and 20,940 tons (19,000 t) of rubberized asphalt was used on the project.
Hegbloom mentioned that various sized reinforced concrete pipe and corrugated steel pipe also was used throughout the project for drainage improvement. Nearly all pipe was installed with a Cat 330 excavator.
Subcontractors on the Blackrock project included: J&M Landscaping, Sudhakar Intl., Crown Fence Co., Pavement Recycling, Statewide Safety & Signs, BJ Reese Enterprises and G & J Heavy Haul.
As of July 2008, Granite Construction had been working on the Manzanar/Independence project, which is similar to the Blackrock project in that it involves expanding and upgrading 12 mi. of Highway 395.
However, the Manzanar project also involves the construction of a four-lane, all-paved road within the city of Independence, which has a population of nearly 600.
Construction operations within the town have resulted in the discovery of numerous underground storage tanks, which belonged to gas stations that were in business during the early 1900s, Lent said.
The discovery of storage tanks caused a delay in construction, as hazardous waste remediation and removal had to be conducted by contractors who initially would not have worked on the project.
Basement access to an 1880s building also was discovered when a sidewalk was removed for replacement.
Expanding sidewalks, constructing shoulders for parking, and installing “historic” overhead lighting also are aspects of the work underway within Independence.
This amount of work within a small community has been at times hectic.
“Impacts to businesses and resident access continues to be a challenge,” Lent said.
Outside of town, the project includes constructing a two-lane bridge over the Los Angeles Aqueduct, and new lanes. The existing two lanes will receive rehab work similar to the Blackrock project.
The project is currently on schedule for a fall 2010 completion, Lent said.
Both projects are part of the Highway 395/State Route 14 Corridor project, that once completed, will provide a four-lane highway from Los Angeles to Lee Vining, an area north of Mammoth near Mono Lake. The stretch of highway from Los Angeles to Lee Vining spans more than 331 mi. (530 km).
Currently only two corridor projects remain, the Olancha/Cartago Four-Lane project on Highway 395 and the Freeman Gulch Four-Lane project on Route 14. CEG
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