Spanning 1.4 mi. (2.2 km), the project consisted of bridge widening and replacement, the relocation of sewer lines, the building of a direct connection between two Placerville streets and highway wide
Located along California’s main route to and from South Lake Tahoe, U.S. Highway 50, the city of Placerville typically is not the site of larger, highway construction projects, as the city has a population of around 10,000.
However, a $35 million highway improvement project — aimed at reducing congestion along Highway 50 and connecting Placerville’s business districts — was recently completed within the city.
As of October, San Francisco-based Mitchell Engineering had finished work on the U.S. Highway 50 Operational Improvement Project, which began in June 2006, according to Mic Restaino, resident engineer for Caltrans District 3.
Spanning 1.4 mi. (2.2 km), the project consisted of bridge widening and replacement, the relocation of sewer lines, the building of a direct connection between two Placerville streets and highway widening.
Construction of the project was broken down in two stages, with five to six sub- stages of construction occurring at each location, said Francisco Charvet, project manager of Mitchell Engineering, who was the lowest qualified bidder on the project.
The majority of stage one work involved replacing the median section of the West Placerville Drive/Highway 50 overcrossing, and connecting West Placerville Drive with Main Street and Forni Road.
In order to connect the three city streets the existing Highway 50/West Placerville undercrossing was demolished and a new bridge was constructed over Hangtown Creek, which runs between Placerville Drive and Main Street.
During bridge construction a combination of owned and rented cranes, concrete pumps, pile driving equipment, backhoes, loaders and grinders were utilized, Charvet said.
Because bridgework occurred above and around Hangtown Creek, Mitchell Engineering and its subcontractors had to comply with U.S. Fish and Wildlife, California Department of Fish and Game, and California Regional Water Quality Control Board agreements, which represented a project challenge.
Specific environmental requirements included protecting the habitat of the California red-legged frogs, which live in and around Hangtown Creek.
Mitchell Engineering also had to deal with environmental issues related to asbestos-containing materials, air monitoring and contaminated materials.
An aspect of both stage one and two construction involved building a Highway 50 eastbound auxiliary lane, which now runs from the Placerville Drive onramp to Clay Street.
Due to the presence of “very hard rock material” track drills and excavators, equipped with hoe-rams and rock breaker attachments, were required to demolish nearly 40,000 psi of rock during highway widening construction, Charvet said.
“The project was extended 33 working days, by change order, as a result of hard rock excavation for onramp construction,” Restaino added.
In total more than 9,800 cu. yds. (7,500 cu m) of roadway and structural material was excavated during the project.
During roadway excavation and fill work other heavy equipment utilized, besides excavators and track drills, included: dozers, backhoes, loaders, compactors, haul trucks and various paving and striping equipment.
Aside from auxiliary lane construction, the majority of stage two construction involved bridgework and sewer line relocation.
Utility relocation work included the replacement of a 5,000 ft. (1,520 m) of existing sewer line/pipe that was located in Hangtown Creek, and the relocation of the sewer collection system along lower Main Street.
Heavy equipment such as dozers, backhoes, loaders, excavators, rollers, compactors and haul trucks were used when relocating and replacing sewer lines.
More than 1,470 yds. (1,350 m) of sewer and drainage pipe was used for this aspect of the improvement project, according to Charvet.
Bridgework that took place during stage two included replacing an eastbound portion of the Placerville Drive/Highway 50 overcrossing and completing the new Hangtown Creek Bridge, which was started in stage one and connects West Placerville Drive to Main Street.
In an attempt to improve the operation of local cross traffic, stage two also included the replacement or widening of three local bridges that connect Main Street to Highway 50.
The Bedford Avenue Pedestrian overcrossing was rebuilt, with CIDH pile work occurring during stage one; and the Spring and Canal street bridges were widened.
Additionally signal upgrades were made at the Canal Street, Spring Street and Bedford Avenue intersections.
When all bridge work reached completion, in both stages, more than 6,400 cu. yds. (4,900 cu m) of structural concrete and more than 1.2 million lbs. (550,000 kg) of bar reinforcing steel was used, Charvet said.
Other materials used during the project included: more than 26,500 ton (24,000 t) of Type-A asphalt concrete, more than 1,020 cu. yds. (780 cu m) of minor concrete, and 2,450 yds. (2,240 m) of concrete barrier.
Throughout the life of the project, a day and night shift of workers was maintained. The peak number of Mitchell field employees reached 60 and was comprised of various crafts including operators, carpenters and laborers.
Because work occurred in two shifts and through Placerville, each stage of construction required a unique traffic-handling plan to accommodate the public, businesses, and emergency services, Restaino said.
Upon completion, the project was awarded the 2009 Project of the Year award from American Public Works Association Sacramento Chapter, in the $10 to $50 million transportation project category,
Subcontractors on the project included: Martin Brothers, asphalt paving; Central Striping, roadway striping and markings; Tennyson Electric, electrical and signalization; Contractors Chemical Inc., polyester overlay and expansion joints; MBI, project barriers; GR Trucking, off-haul trucking; Swisher Concrete, minor concrete; Harris Salinas, bar reinforcing steel; Tilbury Welding, decorative fencing installation; Bailey Fence and Empire Fence, project fencing. CEG