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5. Lifeline Perspective
Pages 135-164

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From page 135...
... In addition to the San Fernando earthquake, research initiatives were established after the 1985 Mexico City earthquake, the 1987 Whittier Narrows earthquake, and the 1989 Loma Prieta earthquake. Research agendas for these initiatives usually focused 135
From page 136...
... The Loma Prieta earthquake offered a number of unique research opportunities. In the lifeline area, this earthquake allowed a detailed examination of seismic design procedures originally introduced as a result of the San Fernando event.
From page 137...
... LIFELINE SYSTEM PERFORMANCE DURING THE 1989 LOMA PRIETA EARTHQUAKE The following section presents brief summaries of lifeline system performance in the Loma Prieta earthquake. These summaries are intended to give an overview of system response, rather than list specific component damages.
From page 138...
... City of Palo Alto Regional Wastewater City of San Fracisco Clean Water Program City of San Jose Sewer City of Santa Cruz Sewer City of Scotts Valley Sewer City of Watsonville Sewer East Bay Municipal Utility District Wastewater Pajaro Community Services District San Mateo—Sewer (indirect) Santa Cruz County Sanitation District South Bayside System Authority Wastewater Sunny Slope County Water District Sewer Union Sanitary District o o o .
From page 139...
... Storage tanks were damaged in Los Gatos, San Jose, Los Altos Hills, Watsonville, Sunny Mesa, San Lorenzo Valley, Scotts Valley, and the Santa Cruz Mountains. Pipeline damage was extensive in areas of ground failure, such as San Francisco's Marina District, Santa Cruz, and Watsonville.
From page 140...
... Damage had been reported in the city of Watsonville, Scotts Valley, and Santa Cruz. Minor damage was also reported at various regional wastewater treatment facilities (Kennedy/Jenks/Chilton, 1990~.
From page 141...
... The majority of relights resulted from customers unnecessarily turning off their own gas in response to hastily worded media messages, which recommended shutoff without specifying "if you smell or hear gas." At the peak of the relight effort, 1,183 servicemen were utilized. Outside utility companies contributing manpower to the relight effort included Southern California Gas, San Diego Gas and Electric, Mountain Fuel, Sierra Pacific, Northwest Natural Gas, and Washington Natural Gas (Phillips and Virostek, 19904.
From page 142...
... It was reported that all leaks were contained within containment dikes and that no fires resulted (EERI, 1990~. Electric Power Primarily as a result of direct damage to transmission substations, 1.4 million PG&E customers lost power following the Loma Prieta earthquake.
From page 143...
... Following the Loma Prieta earthquake, the NSF funded $4.2 million in research through the Loma Prieta Initiative. These funds sponsored various engineering investigations, including studies addressing geotechnical, structural, seismological, and socioeconomic topics.
From page 144...
... Other Research Efforts While publicly funded post-earthquake research has done a great deal to improve the state of the art in earthquake engineering, additional proprietary
From page 145...
... , which addressed such issues as performance, restoration, mitigation, and preparedness; · the National Communications System, which co-sponsored a workshop in 1991 with the NSF entitled "Modeling the Impact of Major Earthquakes on Communications Lifelines: Research Accomplishments and Needs," and a second workshop in 1992 entitled "Assessment of State-Of-The-Art Approaches to Communication Lifeline Modeling for Earthquake Disasters; the purpose of these workshops was to "review the state of the art in modeling the effects of major earthquakes on communications lifelines and to assess the technical feasibility of developing models if none existed"; the presenters at this workshop discussed research results on various themes including seismic testing, actual performance, predictive damage and outage models, and mitigation and preparedness measures (NCS/NSF, 1991, in press) ; and · conference proceedings from various professional organizations, such as the American Society of Civil Engineers/Technical Council for Lifeline Earthquake Engineering (ASCE/TCLEE)
From page 146...
... As discussed in the introduction, the lifelines covered in this paper include: the water supply; · waste water ; · natural gas; oil; electric power; and communication. Water Supply and Wastewater Systems Many of the studies funded by the NSF after the Loma Prieta earthquake focused on the performance of water and wastewater facilities.
From page 147...
... O'Rourke at Cornell University has shown that in the Marina District, where significant liquefaction ground failure occurred (Figure 5-4) , the number of pipeline repairs per unit FIGURE 5-4 Extensive ground failure was observed in the Marina District of San Francisco.
From page 148...
... In the 1989 Loma Prieta earthquake, one of the serious failures to the AWSS system occurred in a pipeline located in the South of Market area (Figure 5-51. As a result of this failure, water supply from the 750,000 gallon Jones Street tank was lost in 30 to 45 minutes.
From page 149...
... Nonstructural components within water and wastewater treatment facilities are prone to damage from sloshing effects. After the Loma Prieta earthquake, D
From page 150...
... Key lessons learned from these studies are Natural gas transmission pipelines and distribution mains demonstrated a high degree of ruggedness when large permanent ground deformations were absent, similar to performance in past earthquakes. Experience during the Loma Prieta earthquake confirmed the ruggedness of buried, welded steel pipeline systems located in competent soils.
From page 151...
... Regardless of the level of damage, power outages in urban areas can be expected to last several days after a significant earthquake to allow for inspection of high-rise buildings for gas leaks and ignition sources. The extended power outage in downtown San Francisco following the Loma Prieta earthquake resulted not from direct damage but from the need to perform building-by-building gas leak surveys prior to energizing the local power grid.
From page 152...
... The vulnerability of these components is generally acknowledged, and various retrofit strategies have been tried. All seven of the 500-kV live-tank circuit breakers in the strongly shaken areas of the Loma Prieta earthquake (the Metcalf and Moss Landing substations)
From page 153...
... Figure 5-6 shows a fiber-optic cable that was stretched when one of the upper spans of the Bay Bridge collapsed during the Loma Prieta earthquake. Although the cable was stretched, there was sufficient slack to accommodate the displacement.
From page 154...
... Several scenarios were run to determine the number of facilities that would be affected in a large earthquake on the Hayward fault in northern California. Based on fairly conservative damage criteria, it was determined that in such an event, the capacity of the network would drop to a possible low of about 67 percent in California and between 92 and 98 percent across the entire United States.
From page 155...
... The ground failure effects observed in northern California after the Loma Prieta earthquake can and have occurred in other parts of the United States. Extensive liquefaction ground failures were observed during the 181 1 and 1812 New Madrid earthquakes.
From page 156...
... The extended power outage in downtown San Francisco following the Loma Prieta earthquake resulted not from direct damage but from the need to perform building-by-building gas leak surveys prior to energizing the local power grid. While most of the city had power restored within a day of the earthquake, the high-rise district was without power twice as long roughly 48 hours.
From page 157...
... (1990) used these methods to validate the vulnerability of the AWSS in the city of San Francisco and the rapid loss of water after the Loma Prieta earthquake.
From page 158...
... 1990. Earthquake Spectra: Loma Prieta Earthquake Reconnaissance Report, Earthquake Engineering Research Institute, Supplement to Volume 6, May.
From page 159...
... 1991. Survey of 15 Utility Agencies Serving the Areas Affected by the 1971 San Fernando and the 1987 Whittier Narrows Earthquakes.
From page 160...
... Liquefaction-induced ground deformation was of key importance to the performance of the water supply in San Francisco and portions of the East Bay during the Loma Prieta earthquake. Correlations among areas of soil liquefaction and locations of buried pipeline damage show a clear pattern of system performance that depends on the severity of liquefaction and the spatial distribution of ground movement.
From page 161...
... Pipeline failures are concentrated in areas where liquefaction-induced permanent ground deformation occurs and can result in draining water storage tanks holding water needed for fire suppression. The old cast-iron pipe along the San Lorenzo River in Santa Cruz failed, which drained reservoirs.
From page 162...
... Finally, time reporting systems, damage categories, and financial recording in accordance with and parallel to Federal Emergency Management Agency's procedures and policies must be set up ahead of time. For implementation, we now need to take these lessons learned to explain how to repair the subsidence problems so that they will not happen again and how to repair major concrete structures standing on long piles with heavy weights.
From page 163...
... Distribution systems in the Marina District, Los Gatos, and Watsonville had to be replaced. Since the Loma Prieta earthquake, a seismic risk factor (soils and proximity to fault zones)


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