Utility Contractor

SEP-OCT 2018

As the official magazine of NUCA, Utility Contractor presents the latest information affecting every aspect of the utility construction industry, including technological advancements, safety issues, legislative developments and instructional advice.

Issue link: http://digital.utilitycontractoronline.com/i/1031723

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Page 31 of 43

32 Utility Contractor | September/October 2018 LEFT: The recontoured banks of Petroleum Creek with streambed remediation complete. RIGHT: The 36-in. transmission line (L-400) exposed in Petroleum Creek prior to construction. [EDITOR'S NOTE: In each issue, Utility Contractor will profile NUCA's Top Job winners. These projects present the association's best and most innovative work that keep our country's utility networks operating at peak performance. To nominate your project for Top Jobs, visit: nuca.com/ topjobs] R-407 Program T he R-407 Program came to fruition due to one of the wettest winters in Northern California in recent history. After one of Pacific Gas and Electric Company's (PG&E's) 36-in. transmission lines was found exposed for 30 ft in Petroleum Creek, an integrity management flag was immediately triggered. PG&E selected Barnard Pipeline Inc. to perform the pipeline relocation. The project took place in an environmentally sensitive area and involved the replacement and relocation of 303 ft of pipeline under Petroleum Creek, in addition to the preparation of an extensive streambed remediation plan. The project team was able to expe- dite all of the applicable permits and mobilized to the site on Aug. 7, 2017. PG&E required an accelerated schedule to meet the mandatory gas clearance on Sept. 19. To meet this schedule, Bar- nard crews worked diligently to clear the right of way (ROW), excavate over 6,000 cubic yards of material, and fab- ricate and hydro-test the new piping. To complete the gas clearance, Bar- nard used cross compression equip- ment to evacuate the gas from Line 400 (L-400) and then repacked it following the successful clearance. Barnard then installed and anchored concrete mats over the newly installed L-400. With the pipeline anchored, Barnard back- filled and compacted L-400. Barnard then recontoured the streambanks of Petroleum Creek and installed 1,454 tons of ½-ton and ¼-ton rock slope protection (RSP) along the recontoured banks to ensure stability and prevent future erosion. The project finished with zero at-fault dig-ins or line strikes, and zero OSHA recordable incidents. One of the largest challenges faced by the project team was the relation- ship between the PG&E easement and the Western Area Power Administra- tion (WAPA) easement. The easements paralleled each other and only allowed for a 10-ft horizontal offset between the existing L-400 and the newly in- stalled L-400. Due to the proximity and the 24-ft depth of excavation, Barnard implemented a combination of sloping and shoring systems, which was essen- tial for ensuring the full support of the existing L-400 throughout construc- tion. Once Barnard executed the gas clearance, the abandoned segment of L-400 was safely removed. Another challenge faced throughout construction was an irrigation outflow point located 200 ft directly upstream from the site. The irrigation outflow discharged thousands of gallons of wa- ter daily, which in turn flowed directly toward the pipeline excavation. Barnard could not shut off the irrigation system due to the impacts it would have on the local farming community at harvest time. To prevent the water from flood- ing the excavation, Barnard installed a water bypass system that spanned the length of excavation. Barnard then di- verted the water and discharged it fur- ther downstream where it no longer in- terfered with construction. Barnard's subcontractors on the R-407 Program included: Milbar Hydro-Test Inc.; Cal Inc.; Atlas Tree Surgery Inc.; PSC Environmental Ser- vices LLC; Guida Surveying Inc.; Larry Jenkins Trucking Inc.; and Nordic In- Category: Oil and Gas Pipeline Contractor: Barnard Pipeline Inc. Owner: Pacific Gas & Electric Company City/State Project: Dunnigan, California

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