Chile - The magnitude 8.8 offshore Maule region Chile earthquake of February 27, 2010 : preliminary summary of damage and enginering recommendations

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This paper documents the effects of the 2010 earthquake on Chile's infrastructure and economy, for the purpose of future policy recommendations. The assessments and recommendations in this report are preliminary, and need further analysis and development in order to substantiate a basis for policy decisions. The evaluation is based on discussions with expert seismologists and earthquake engineers. The report summarizes the performance of most classes of buildings and infrastructure, and makes specific recommendations regarding further data that need to be collected and analyzed in order to understand what can be done to improve future performance and future codes; the analyses that need to be conducted to evaluate the risks due to the action of earthquakes and tsunami in Chile; and the earthquake risk-reduction projects that can be undertaken to eliminate or reduce future risks in Chile to acceptable levels. The earthquake affected 82 percent of the country's population. The final official casualty count includes 577 deaths. According to press reports at the time of this report's preparation, the overall damage to infrastructure is estimated at 30 billion US dollars. If building interior damage and business interruptions were also included, the overall economic loss would increase substantially, reaching 50 to 60 billion US dollars. The recommendations provided throughout this report include the establishment of a national program for earthquake risk reduction; establishment of specific programs for damage prevention; revision and improvement of the Chilean seismic code; creation of new research programs, and improvement of existing ones; creation of a national seismic network; and construction of a monument from a collapsed historical bridge.
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 70138 THE MAGNITUDE 8.8 OFFSHORE MAULE REGION CHILE EARTHQUAKE OF FEBRUARY 27, 2010 PRELIMINARY SUMMARY OF DAMAGE AND ENGINEERING RECOMMENDATIONS A Report to the World Bank by FRANCISCO MEDINA - PETER I. YANEV - ALEXANDER P. YANEV April 18, 2010 Rev. 01: 07/07/10 Cover: Torre O’Higgins office building in Concepción. Back Cover: Constitución. The Magnitude 8.8 Offshore Maule Region, Chile Earthquake CONTENTS Acknowledgments, iv Executive Summary, v Prologue (by V.V. Bertero), vii 1. Background and Summary of the Investigation .......................................................... 1 2. General Engineering Observations.............................................................................. 3 3. Detailed Engineering Observations............................................................................. 4 3.1. Effects of the earthquake duration on building performance, 4 3.2. Effects of soil conditions on building performance, 5 3.3. Ground motion records, 6 3.4. Low-rise buildings (up to 4 stories), 6 Old and non-engineered buildings Engineered confined-masonry buildings Post-1950 buildings Steel-framed buildings Tsunami effects to buildings 3.5. Mid-rise and high-rise buildings (over 4 stories), 13 Damage to shear wall buildings Damage to exterior building cladding Damage to unusual architectural exterior details 3.6. Interior architectural and equipment damage, 20 3.7. Other structures, 23 Hospitals Historic public buildings 3.8. Infrastructure, 25 Santiago International Airport Santiago Metropolitan Train Transportation infrastructure Power generation, transmission, and distribution Ports Communications 3.9. Industry, 30 General comments on industry Food industry Wine industry Fishing industry 4. Emergency Building Inspection and Emergency Response ........................................ 33 5. Conclusions ................................................................................................................. 33 6. Recommendations ....................................................................................................... 34 6.1. National program for damage prevention and earthquake risk reduction, 34 6.2. Damage prevention and earthquake risk reduction, 34 6.3. Seismic code, 35 6.4. Education, training, and research, 35 6.5. Seismic network, 36 6.6. Monument, 36 F Medina ã PI Yanev ã AP Yanev iii The Magnitude 8.8 Offshore Maule Region, Chile Earthquake ACKNOWLEDGEMENTS Comments to a draft copy of this report were solicited from: Christoph Pusch, Regional Coordinator, Disaster Risk Management and Global Facility for Disaster Risk Reduction and Recovery, World Bank, Washington, DC, USA Fernando Ramírez, Disaster Management Specialist, World Bank, Washington, DC, USA Joaquín Toro L., Senior Disaster Risk Management Specialist, World Bank, Washington, DC, USA Patricio Bonelli Canabes, Profesor Titular, Universidad Técnica Federico Santa María, Valparaíso, Chile Francisco Brieva Rodríguez, Decano, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile Jorge Crempien Laborie, Decano, Facultad de Ingeniería, Universidad de Los Andes, Santiago, Chile Ernesto Cruz Zabala, Profesor Titular, Pontificia Universidad Católica de Chile, Santiago, Chile Carlos Guzmán Jara, Secretario Regional Ministerial de Obras Públicas, Región del Bío-Bío, Chile Jaime Retamal Pinto, Jefe de Gabinete del Ministro de Obras Públicas, Santiago, Chile Fernando Yáñez Uribe, Director, Instituto de Investigaciones y Ensaye de Materiales, Universidad de Chile, Santiago, Chile Rafael Alaluf, Earthquake Risk Management International, Ltd., Istanbul, Turkey Richard Andrews, Consultant to the World Bank, Emergency Management, Redlands, California, USA Jorge E. Medina carefully reviewed and edited the text of this report. The following individuals provided us with valuable assistance during the field investigation in Chile: Juan Manuel Aguiló Melo, Fotógrafo, Teatro Regional del Maule, Talca, Chile Sergio Patricio Aguiló Melo, Diputado, Región del Maule, Congreso Nacional, Chile Sergio Baeriswyl Rada, Asesor en Temas Urbanos, Ilustre Municipalidad de Concepción y Gobierno Regional del Bío-Bío, Chile Klaus Bataille Bollweg, Profesor Titular, Departamento de Geofísica, Universidad de Concepción, Chile Rubén Boroschek Krauskopf, Profesor Asociado, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile Carolina Chacón Fernández, Directora, Hospital Regional de Talca, Chile Ricardo Faúndez Ahumada, Director Regional de Arquitectura, Región del Bío-Bío, Chile Gian Mario Giuliano Morbelli, Profesor Asociado, Departamento de Ingeniería Civil, Universidad de Concepción, Chile Carlos Guzmán Jara, Secretario Regional Ministerial de Obras Públicas, Región del Bío-Bío, Chile Pablo Lucero Márquez, Arquitecto, Viña del Mar, Chile Oscar Mahuzier García, Coronel de Ejército, Coordinador de Demoliciones Región del Bío-Bío, Chile María Pilar Matute Willemsen, Encargada Regional de Patrimonio, Región del Maule, Chile María Ofelia Moroni Yadlin, Profesora Asociada, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile ?ngela Rivera Estrada, Arquitecta Revisora, Ilustre Municipalidad de San Pedro de la Paz, Chile Karin Rüdiger Canaan, Asesora Urbanista, Ilustre Municipalidad de Concepción, Chile Mauricio Sarrazín Arellano, Profesor Titular, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile Víctor Mauricio Sepúlveda Aravena, Subdirector de Operaciones, Hospital Regional de Talca, Chile John Abruzzo, Senior Principal, Thornton Tomasetti, Oakland, California, USA Rafael Alaluf, Earthquake Risk Management International, Ltd., Istanbul, Turkey Matt Steiner, Senior Project Engineer, Thornton Tomasetti, Irvine, California, USA Andy Thompson, Associate, Arup Consulting Engineers, San Francisco, California, USA However, we are most grateful to the Chileans who, in the middle of this difficult period, had the forbearance to graciously tolerate our team’s professional curiosity. iv F Medina ã PI Yanev ã AP Yanev The Magnitude 8.8 Offshore Maule Region, Chile Earthquake EXECUTIVE SUMMARY Our team of structural and earthquake engineers investigated the effects and damage from the February 27, 2010 Chile earthquake and tsunami to: (1) observe first hand how new and old buildings and infrastructure performed; (2) study what needs to change in our design and construction practices as well as our building codes to reduce future damage and loss of life; and (3) evaluate what Chile can do to reduce to an acceptable level the remaining risks due to earthquakes and tsunami. We investigated much of the most affected region of Chile, including its three largest metropolitan areas (Santiago, Valparaíso/Viña del Mar and Concepción) and several other cities located in between. We also toured the coastal region south of Valparaíso to Constitución by air and Constitución itself by land. This report is based on the professional experience of the authors, their field visits in Chile, and their discussions with many earthquake professionals working in the research and the practice of seismology and earthquake engineering. The assessments and recommendations are preliminary and need further analysis and development in order to substantiate a basis for policy decisions. From an engineering perspective, this is the most important earthquake in modern earthquake history. With a magnitude (Mw) approaching 9, it is the first mega-earthquake to strike a modern city full of state-of-the-art structures, industries, and infrastructure. Chile has excellent structural and earthquake engineering. Additionally, it has a modern building code that is comparable to and often has exceeded those of California and Japan. All this was tested by an intense ground shaking that lasted about 120 seconds –compared to 40 and 20 seconds for the 1906 and 1989 San Francisco earthquakes, which had magnitudes of 7.9 and 6.9, respectively. Thousands of buildings collapsed or were severely damaged. Most of these were older buildings built without an earthquake engineering design. These included important government buildings, hospitals, residential and commercial buildings, and industrial infrastructure. A few new high-rise buildings, including residential and commercial buildings, were damaged beyond repair. A handful of modern buildings totally or partially collapsed. Most buildings that were designed to resist earthquakes performed well. In contrast, the non-structural features of some new buildings performed poorly. Poorly performing features include decorative architectural details, suspended ceilings (locally called “american ceilings?), and poorly anchored or braced equipment. In this report we summarize the performance of most classes of buildings and infrastructure. In addition, we make specific recommendations regarding: (1) further data that need to be collected and analyzed in order to understand what can be done to improve future performance and future codes; (2) the analyses that need to be conducted to evaluate the risks due to the action of earthquakes and tsunami in Chile; and (3) the earthquake risk-reduction projects that can be undertaken to eliminate or reduce future risks in Chile to acceptable levels. The earthquake affected 82% of the country’s population. The final official casualty count includes 577 deaths. According to press reports at the time of this report’s preparation, the overall damage to infrastructure is estimated at 30 billion US dollars. If building interior damage and business interruptions were also included, we estimate that the overall economic loss would increase substantially, reaching 50 to 60 billion US dollars. This is a rough F Medina ã PI Yanev ã AP Yanev v The Magnitude 8.8 Offshore Maule Region, Chile Earthquake estimate by the authors, based on prior experience with similar estimates published by the press after numerous past earthquakes. Much of these losses could have been prevented with simple engineering details and good seismic risk management at a reasonable cost and time. Based on our observations, we make recommendations throughout the text of this report, and we summarize some of these recommendations at the end as follows: (1) establish a national program for damage prevention and earthquake risk reduction; (2) establish and conduct specific programs for damage prevention and earthquake risk reduction; (3) revise and improve the Chilean seismic code; (4) create and conduct new education, training and research programs, and improve existing ones; (5) create a national seismic network; and (6) create a monument from a collapsed historical bridge. NOTE: This report is available in Spanish. NOTA: Este informe está disponible en español. vi F Medina ã PI Yanev ã AP Yanev The Magnitude 8.8 Offshore Maule Region, Chile Earthquake PROLOGUE In this excellent report the authors summarize the behavior of most types of buildings and infrastructure which were subjected to the effects and damage of the February 27, 2010 Chilean earthquake and tsunami. The General Engineering Observations are very appropriate and I agree with the assertion that, from the human loss point of view, the Chilean public built infrastructure as well as the private provided the people with a level of protection without equal worldwide. Chapters 3 and 4, Detailed Engineering Observations and Emergency Building Inspection and Emergency Response, respectively, give a clear idea of the occurring damage, of the losses that this damage produced, and that there exist problems in the safety evaluation of the damaged buildings. The losses occurring due to a seismic event should be evaluated, adding, amongst other parameters, the civic and social outcomes of the earthquake effects, which are not considered in this report. For example, the press has published that civic turmoil occurred in certain areas. Consequently, the civic preparation, as well as the technical preparation covered in this report, should be an integral part of the emergency response. Based on their observations and experience, the authors estimate that the losses could be 60 billion dollars, which is double of press reports. I think that, according to the damage presented in Chapter 4 and in other published reports, the losses can reach and even exceed said amount when adding direct and indirect damages. This is a significant figure, close to 71% of the budget that the Chilean Government considered for 2010. The authors offered 24 recommendations on 6 different topics directed at the nation of Chile in general. These are very good recommendations that, for the most part, will require studies and/or research, which would benefit enormously from the collaboration with foreign scientists and professionals. My experience in this type of collaboration was highly positive and fruitful in the case of the 1985 Mexican Earthquake, where bi-national groups were integrated, collaborating in a large amount of studies. This collaboration was of mutual benefit and learning, achieving significant knowledge advances in the areas of earthquake engineering and seismology, which derived in specific and practical recommendations for codes and procedures. Special attention must be directed to the recommendations addressed to protect what is already built (especially low-cost housing), to reduce the loss of life, and to establish a chain of responsibility that is transparent in the engineering, construction and inspection of buildings and infrastructure. Vitelmo V. Bertero Professor Emeritus University of California Berkeley, California July 2010 F Medina ã PI Yanev ã AP Yanev vii THE MAGNITUDE 8.8 OFFSHORE MAULE REGION, CHILE EARTHQUAKE OF FEBRUARY 27, 2010 PRELIMINARY SUMMARY OF DAMAGE AND ENGINEERING RECOMMENDATIONS 1. BACKGROUND AND SUMMARY OF THE INVESTIGATION A magnitude (Mw) 8.8 earthquake occurred in Chile at 3:34 am on February 27, 2010. The epicenter was roughly midway between Talca and Concepción, offshore on the well-known Chilean Subduction Zone Fault. In addition, a multitude of strong aftershocks continued to occur for several weeks along different sections of the fault, some with magnitudes over 6; the strongest so far is Mw=7.1. The earthquake affected a large area of Chile, from Santiago and coastal Valparaíso/Viña del Mar in the North, to well south of Concepción. The affected region includes Chile’s three largest metropolitan areas. The strong ground shaking, which lasted well over 60 seconds and as much as 120 seconds, affected this area from the coast, which is closest to the faulting, to much of the interior of Chile towards the East. Some of the most serious earthquake damage was to cities in the interior, such as Talca. A major tsunami, immediately after the earthquake, caused extensive damage along much of Chile’s most populated coast, from Coronel (near Concepción) in the South to Iloca (northwest of Talca) in the North. The authors of this report were all in California, USA, when the earthquake occurred. We formed an engineering team to investigate the effects of the earthquake and to observe important new lessons. We arrived in Santiago shortly after the Santiago International Airport opened, five days after the earthquake. We spent about 9 days investigating damage. One of the team members, Dr. Francisco Medina, remained in Chile for another 11 days and continued the investigation. We received the support of engineers and academicians from several Chilean universities, structural and earthquake engineers from Chile, and members of other engineering investigating teams from throughout the world. We received invaluable assistance and access to numerous facilities and buildings throughout the stricken area from other professional Chileans, Chilean government employees, and other technical and non- technical contacts. We concentrated our research on the following areas (see Figure 1): 1. Santiago and its general Metropolitan Area. 2. Valparaíso and particularly Viña del Mar. 3. Talca and its surrounding area. 4. Concepción and its Metropolitan Area. 5. Talcahuano and its surrounding area, including the coastal region around Talcahuano and Coronel. 6. Constitución, its surrounding area, and the coast to the north up to Valparaíso (by air). We traveled by car to all of the areas listed in 1 to 5 above. We observed and investigated the effects of the earthquake along and around the Pan American Highway in Central Chile (Santiago to Chillán), the highway from Chillán to Concepción, and the highway from Santiago to Valparaíso, covering an approximate total of 1,000 km. Along the way, we investigated damage to many smaller towns, such as Santa Cruz and San Javier. We observed F Medina ã PI Yanev ã AP Yanev 1 The Magnitude 8.8 Offshore Maule Region, Chile Earthquake Figure 1. Map of the affected region of Chile, showing the location of the epicenter, generalized shaking intensities (colored dashed lines), our approximate main land route (solid black line), our approximate route by air (dotted line), and the more important regions that we investigated (triangles). Base map: United Nations Office for the Coordination of Humanitarian Affairs www.reliefweb.int . 2 F Medina ã PI Yanev ã AP Yanev
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