Alternative Studies of Water Transmission Pipelines Crossing the Hayward Fault

Abstract eng:
The Bay Division Pipelines (BDPLs) Nos. 3 and 4 are vital components of the San Francisco Public Utilities Commission’s (SFPUC’s) transmission system that delivers water from Hetch Hetchy Reservoir in Yosemite National Park to the San Francisco Bay Area. The pipelines cross three traces of the Hayward Fault, which is capable of producing a magnitude 7.25 earthquake and over 6 feet of horizontal fault offset. The alignment of the SFPUC pipeline right-of-way is such that offset of the fault will produce compression in the 78-inch and 96inch-diameter pipelines. A large earthquake on the Hayward Fault would almost certainly rupture both BDPLs 3 and 4 causing localized flooding and loss of water supply to the San Francisco Bay Area. Adding to the complexity of the project, the fault crossing is located in a highly congested and trafficked area at the intersection of the Interstate 680 freeway and Mission Boulevard in Fremont, California. This unusual situation of large-diameter pipelines constrained by local right-of-way restrictions to a compression fault crossing requires a unique solution to mitigate the danger. Nine alternatives were developed to address the situation considering cost, constructability, seismic reliability, operations and maintenance, environmental and governmental permitting, and community impact. The goal of the alternative studies is to yield a solution that provides a high level of survivability and operability after a major earthquake and constructability within a confined construction area, while minimizing disruption to the community, traffic, and water delivery.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket