ARB`s underground and industrial operating groups are independent entities yet they work closely together maintaining the corporation`s principles. Our operating groups are made up of an avid workforce who take pride in our work, and are focused on doing the best to ensure quality of work. ARB`s extensive and diverse capabilities allow the corporation to respond to the changing marketplace, addressing traditional client needs, while meeting new challenges, such as accelerated construction of projects or building in sensitive ecosystems. We incorporate the latest technology and have decades of experience in providing the most reliable services.
San Francisco Gas Distribution Project
In a very congested area of San Francisco, ARB completed a gas distribution project for Pacific Gas and Electric. The work involved, utilizing a mini horizontal directional drilling rig for the installation of 5,000 ft of 2-inch polyethylene natural gas main for main and service replacement work. The directional drilling method allows the work to take place with much less inconvenience to the public by reducing the number of excavations. ARB crews also replaced 210 services to homes and rebuilding all meter sets.
PG&E Gas Distribution Project
ARB has been working under a system wide contract with PG&E for the installation of guard post protection for natural gas meters. The work typically requires placement of 2-in. and 4-in. steel posts filled with concrete. Several thousand have been completed and our contract calls for 10,000 to be installed over a 3 year period. The projects are small but spread over a large geographic area ranging from Bakersfield, Ca. all the way up to the California/Oregon border.
Long Beach Gas Distribution Project
ARB was awarded a contract with Long Beach Energy for the replacement of multiple natural gas mains, which varied in diameter from 2-inch polyethylene to 12-inch steel pipe as well as work on 628 services to be replaced throughout the city. Methods of installation included open trench, horizontal directional drilling, cut and bore as well as multiple bridge crossings, which were completed using a barge in the water below. With two crews, the work lasted approximately 7-months.
Warner Avenue Relief Sewer Project
This construction project stretched from Los Patos and Bolsa Chica to Warner and Springdale in Huntington Beach, California. The project was built entirely within public streets and was composed primarily of three major operations. The first operation was approximately 2,000 LF of 3 reinforced concrete encased 18-inch PVC rapped pipe. The pipe encasement was designed to withstand the load of two lanes of traffic since the actual alignment was not more the three feet from the top of pavement. There were several aspects to the operation that made it unique and difficult to complete. First in order to prevent the pipe from floating in the fresh concrete the encasement had to be poured in three stages. In order to start pouring, a bottom layer of reinforcing steel with vertical bars protruding over the pipe had to be placed first and completed before pipe could be installed and the rest of the reinforcing was placed.
The pipe could not be placed in the trench first because there would then be no way to maintain the pipe alignment, this was necessary because the sewer utilized a gravity feed system. The second operation was a 200 LF jack and bore operation that extended underneath the Wintersburg Channel in Huntington Beach. The jacking of the 48-inch steel casing alone was not the difficult aspect of the operation. The ground conditions encountered required continuous dewatering throughout the duration of the process. Three well points were drilled, sump pumps were installed which fed ground water to a desalting tank that then deposited the water into the nearby sewer system. The pumps had to be monitored continuously to ensure that the pumps and the generator powering the pumps were all operating normally. Also, the jacking pit and receiving pits were 30 feet deep in saturated sandy and clay soil with existing utilities running through the area requiring a unique shoring design.
The last major operation was construction of 3,500 LF of a 21-inch VCP sewer pipeline, ranging in depth from 5 to 26 feet. Since this area is in close proximity to the Pacific Coast the ground conditions were rather sandy and saturated, which made the trench making portion of this operation very difficult. More than half of the 3,500 LF the trench had to be maintained with solid sheeting; which meant that beams had to be drilled in ahead of the excavating crew and then plates were lowered down between the beams while the trench was being excavated. This was very slow and a dangerous operation taking into account the bad soil conditions, the location of the trench in proximity to live traffic and the overall extreme depths that the sewer needed to meet.
