Doubling A Pipeline

by Gary Walker, Vice Pres.; PGT-PG&E Pipeline Expansion, 45 Fremont St., San Francisco, CA 94105-1570,
John Myrick, Project Manager; PGT-PG&E Pipeline Expansion, 45 Fremont St., San Francisco, CA 94105-1570,

Serial Information: Civil Engineering—ASCE, 1994, Vol. 64, Issue 1, Pg. 50-53

Document Type: Feature article


The 36 in. natural gas pipeline built 32 years ago by Pacific Gas and Electric (PG&E) its subsidiary Pacific Gas Transmission (PGT) from Canadian fields to central California has had its capacity increased by two-thirds with construction of a second parallel pipeline. In addition to 827 miles of 42 and 36 in. pipe totalling 380,000 tons, the project included building one new compressor station and retrofitting 17 other compressor stations and three major meter stations. The route traverses fast flowing rivers and seven mountain ranges through every type of terrain from heavily wooded forests to the low-lying Sacramento delta. Steep mountain slopes, upland rolling hills,islands below sea level and 200 miles of volcanic rock provided special challenges. Elevations vary from 5,400 ft above sea level in southern Oregon to 10 ft below sea level in California. The 100 ft right-of-way, acquired in the late 1950s, provided ample room for the parallel second pipe, which generally lies about 30 ft from the original line. The project design and construction complied with all national and state environmental laws, requiring approval by numerous agencies. Bechtel, which designed and engineered the first line, was responsible for planning, design, engineering, procurement, right-of-way acquisition and construction of the second pipeline.

Subject Headings: Gas pipelines | Sea level | Natural gas | Construction management | Project management | Pipeline design | Mountains

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