Loma Prieta, California, Earthquake of October 17,1989: Performance of the Built Environment
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The Lorna Prieta, California, Earthquake/ of October 17, 1989-Lifelines ANSHEL J. SCHIFF, Editor PERFORMANCE OF THE BUILT ENVIRONMENT Thomas L. Holzer, Coordinator U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1552-A Prepared in cooperation with the National Science Foundation UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1998 DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Charles GoGroat, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does no$ imply endorsement by the U.S. Government Manuscript approved for publication, August 5, 1997 Text edited by George A. Havach Library of Congress catalog-card No. 92-32287 For sale by the U. S . Geological Survey Information Services Box 25286 Federal Center Denver, CO 80225 CONTENTS Pages Modeling the impact of the earthquake on telecommunication services------ 37 By Michael L. Cohen Water and wastewater systems...................................................... 47 By LeVal Lund, John McLaughlin, Curt Edwards, Gordon Laverty, Holly Cornell, Alvin R. Guerrero, Michael Cassaro, Andries Godshack, George Brodt, Donald B. Ballantyne, Ronald Eguchi, Mary Pickett, Omar Abu-Yasein, Chenwun Lay, Anshel J. Schiff, James R. Blacklock, and Steven French Water- and wastewater-treatment plants------ - - - ---------- - ------ - - 79 By William Heuback and Donald B. Ballantyne Lessons learned by water and wastewater utilities-------------------------------- 87 By Mark Pickett and Gordon L. Laverty Transportation systems................................................................ 99 By Joel Markowitz Transportation systems-seaports .................................................. Ill By Charles R. Farrar and A. Claude Griffin Transportation systems-passenger railways and buslines--------------------- 121 By Stuart D. Werner and Anshel J. Schiff . Residential natural-gas piping and appliances------------------------------------ 125 By Peter W. McDonough Repair patterns for the gas-distribution system in San Francisco-------------- 129 By Douglas G. Honegger THE LOMA PRIETA, CALIFORNIA, EARTHQUAKE OF OCTOBER 17,1989: PERFORMANCE OF THE BUILT ENVIRONMENT LIFELINES INTRODUCTION By Anshel J. Schiff, Precision Measurement Instruments and Stanford University CONTENTS demonstrated that the tasks of preparing lifelines in "earth- quake country" were incomplete-indeed, new lessons had Page to be learned. A 1 1 2 2 LIFELINES AND THE ORGANIZATION OF 2 THEIR INVESTIGATION 3 3 The 14 papers in this chapter describe the earthquake 3 performance of lifelines. Because one major consequence of 3 4 the disruption of lifelines is its impact on emergency response, 4 many of these papers also discuss the impact of lifeline dis- 4 ruption on the emergency-response communities. Three additional papers that are related to lifelines ap- pear in other volumes of this series. The first paper (O'Rourke LOMA PRIETA- and others, 1992) describes the performance of lifelines in A LIFELINES EARTHQUAKE the Marina District; the second paper (Durkin and others, 1994) describes the performance of the Public Safety An- To the general public who had their televisions tuned to swering Point in Santa Cruz County, Calif.; and the third watch the World Series, the 1989 Loma Prieta earthquake paper (Yashinsky, 1998) describes highway systems. was a lifelines earthquake. It was the images seen around the The postearthquake investigation of lifelines presents world of the collapsed Cypress Street viaduct, with the fran- several unique problems in comparison with the investiga- tic and heroic efforts to pull survivors from the structure that tion of, say, a severely damaged building. First, lifelines are was billowing smoke; the collapsed section of the San Fran- spatially distributed systems, and so it is extremely difficult cisco-Oakland Bay Bridge and subsequent home video of a for a single individual to cover an entire system. Second, each car plunging off the open span; and the spectacular fire in the lifeline is typically a collection of various facilities, such as Marina District of San Francisco fed by a broken gasline. To buildings or structures, links that interconnect the facilities, many of the residents of the San Francisco Bay region, the and equipment that may function as an integrated whole that relation of lifelines to the earthquake was characterized by is the lifeline. Indeed, some lifelines, such as seaports, are a sitting in the dark because of power outage, the inability to collection of other lifelines and specialized facilities. The need make telephone calls because of network congestion, and the for specialized knowledge about the construction, operation, slow and snarled traffic. Had the public been aware of the interaction, and earthquake performance of structures, equip- actions of the engineers and tradespeople working for the utili- ment, and system operations makes the investigation of life- ties and other lifeline organizationson the emergency response lines such a challenge. Finally, in reporting on lifeline damage, and restoration of lifelines, the lifeline characteristics of this it is important to do more that count the failures. To apply the earthquake would have been even more significant. Unob- lessons that can be learned from earthquake damage, the po- served by the public were the warlike devastation in several tential failure modes, the factors that may have contributed to electrical-powersubstations, the 13 mi of gas-distribution lines the failures, and the impact of failures on the facility and the that had to be replaced in several communities, and the more lifeline must all be identified. To address these issues, the than 1,200 leaks and breaks in water mains and service con- Earthquake Investigation Committee of the Technical Coun- nections that had to be excavated and repaired. cil on Lifeline Earthquake Engineering (TCLEE) of the Like the 1971 San Fernando, Calif., earthquake, which American Society of Civil Engineers (ASCE) has developed was a seminal event for activity to improve the earthquake training materials and conducted training courses for lifeline performance of lifelines, the 1989 Loma Prieta earthquake investigators (Schiff, 1991). A2 PERFORMANCE OF THE BUILT ENVIRONMENT After an earthquake, lifeline personnel have little time the failures. It continues with an identification of the impact to discuss damage and its impact until service is returned to of the damage and with comments on the emergency response normal. Many lifeline facilities have controlled access, and and recovery, and concludes with observations and recom- for safety reasons, investigators are required to be accompa- mendations. nied by lifeline personnel, and so the investigation puts an added burden on personnel at the facility. Also, the large spa- NOTABLE OBSERVATIONS ON tial distribution of lifelines means that it takes time for life- LIFELINE PERFORMANCE line personnel to gather and assemble the information AND ITS CONSEQUENCES necessary to complete a picture of system damage and its impacts. Because of the importance of restoring lifeline func- No attempt will be made here to summarize the find- tions, the cleanup of damage and the repair of the system ings of the 11 papers that deal with lifeline performance. starts immediately after the earthquake is over. For some life- Instead, I will highlight those features that stand out because lines, such as electrical-power and communication systems, of their uniqueness or importance. much of the damage can be cleaned up within hours after the Significantly, many of the major lifelines in the San earthquake. For lifelines with buried distribution lines, such Francisco Bay region were rather distant from the earthquake as water, gas, and sewage systems, a lengthy restoration proc- epicenter, and the ground motions were generally of moder- ess may be required in which damaged components must be ate magnitude and duration. However, the ground motions identified, located, excavated, repaired, and tested. Thus, in many of these communities from future earthquakes on much of the damage may not be known by the utilities until faults that run through or adjacent to them are expected to be days or weeks after an earthquake. For this reason, the in- much more severe. vestigation of lifelines requires an immediate response to The poor performance of emergency power affected observe damage before it is cleared, as well as later followup several lifelines and critical facilities, including powerplants, investigations once an overall picture of system damage and telephone-company central offices, airports, water systems, response can be pieced together. hospitals, and emergency-operation centers. A broad range The investigation of these systems was coordinated by of problems with emergency-power systems were observed. the Earthquake Investigation Committee of the TCLEE; the Failure modes and recommended practices for emergency- primary coordinators were Anshel J. Schiff and LeVal Lund. power generators are discussed by Schiff, Swan, and Mastuda Members of the committee, primarily from outside of the San (this chapter). Francisco Bay region, members from the other technical com- mittees of the TCLEE, and others worked on the investiga- tion. Most of the papers in this chapter originally appeared in ELECTRICAL-POWER SYSTEM the preliminary report by Schiff (1990); many of these pa- pers have now been revised to incorporate information gained The types of electrical-power-system damage