AN ABSTRACT OF THE DISSERTATION OF Stephanie Lange for the degree of Doctor of Philosophy in Civil Engineering presented on May 16, 2019. Title: Numerical Response of Concrete-Lined Tunnels Crossing Active Faults Abstract approved: Scott A. Ashford A challenge for municipal authorities of growing urban areas is to provide larger and faster transportation and utility networks that are safe and resilient to signif- icant disruptions after an earthquake event and other disasters. Urban regions, like the San Francisco Bay or the Los Angeles area, are situated in seismically ac- tive regions. In these areas, underground structures, such as water ducts or metro tunnels, must cross active faults to ensure population sustainability. It is commonly known that earthquakes with magnitudes greater than M6.0 can cause significant damage to tunnels in seismically active areas. In particular, large strains due to fault offsets and ground shaking can lead to severe damage in the tunnel lining, (e.g., concrete spalling), which can lead to potential closure and disruptions to the transportation network. Examining the behavior of concrete lined transportation tunnels built through active fault zones is critical to ensure resilient design and safe operations. Under- standing the response of tunnels crossing active faults will further inform reha- bilitation and maintenance measures and support tunnel safety. A 2D model of a circular reinforced concrete tunnel crossing an active fault is developed within the finite element framework OpenSees. A parametric study with varying struc- tural and ground properties is performed. The effects of earthquake magnitude, geology, fault zone width, and structural properties of the tunnel are studied and assessed to develop novel tunnel design strategies to accommodate large fault mo- tions and to minimize tunnel service disruptions. The research is based on three main questions. (1) Can we give guidance when it is acceptable for a tunnel to cross an active fault? (2) What is the influence of faulting on the circular tunnel lining in the cross-section, but also along the longi- tudinal tunnel axis? and (3) What consequences and generalizations can be drawn to support serviceability of the tunnel after an event? Guidance to engineers on these research questions include a possibly reduced length of retrofit measures along the longitudinal tunnel axis where the tunnel crosses the active fault zone. This assessment is based on localized strains and stresses in the concrete lining. The flexural displacement capacity of the tunnel beam ranges between 0.2 % and 2 % of the inner tunnel diameter. A corresponding earthquake magnitude threshold for reaching peak compression concrete strain can be as low as M5.5 at active fault crossings. A generalization that can be drawn is the interaction between the tunnel diameter and the fault zone width, where a fault zone width of less than 1 to 2 times the tunnel diameter might be a larger concern for the tunnel lining due to abrupt shearing. The applicability of such research to existing tunnels is assessed for the Berke- ley Hills tunnels crossing the active Hayward Fault. The ultimate threshold dis- placements of the tunnel beam model are correlated to earthquake magnitudes. An evaluation with charts results in similar earthquake magnitude thresholds for concrete failure compared to a specific 2D numerical analysis. This shows that a simplified chart assessment that predicts an approximate threshold of an earth- quake magnitude the concrete lining is able to withstand, might be applicable for early stage projects, e.g. during a feasibility assessment. c Copyright by Stephanie Lange May 16, 2019 All Rights Reserved Numerical Response of Concrete-Lined Tunnels Crossing Active Faults by Stephanie Lange DISSERTATION submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented May 16, 2019 Commencement June 2019 Doctor of Philosophy dissertation of Stephanie Lange presented on May 16, 2019. APPROVED: Major Professor, representing Civil Engineering Head of the School of Civil and Construction Engineering Dean of the Graduate School I understand that my dissertation will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my dissertation to any reader upon request. Stephanie Lange, Author ACKNOWLEDGEMENTS This work would not have been possible without the support of many individuals during my time at Oregon State University. I am grateful for their support and experience. Firstly, I would like to express my sincere gratitude to my advisor Dr. Scott Ashford, who has been supportive of my career goals and who worked actively to provide me with his support, guidance, and mentorship. He has provided me with unique academia and industry connections. His guidance helped me in key aspects of my life and work, and improved my presentation skills. I am thankful to my co-advisor Dr. Ben Mason. He has provided thoughtful comments, suggestions, and relevant references for the successful application for the National Science Foundation Graduate Research Fellowship, which is greatly appreciated. I was fortunate to work with my co-advisor Dr. Michael Scott. My sincere thanks to him for his support in structural analysis and especially in men- toring me in OpenSees. I am grateful for him presenting the research poster at the 11th NCEE conference, I was not able to attend. I also thank him for his support of the tunnel course, for not only being the professor on record, but also for advising on teaching and for grading all student work. All my students were pleased to get a deserved A. I am grateful for Dr. Michael McRae for initiating the research subject and supporting this research with detailed information on the Berkeley Hills Tunnels. I would like to thank him for his support of my tunnel engineering career and for giving valuable advice. I am truly grateful to him. I would also like to express my sincere thanks to my dissertation committee members, Dr. David Trejo and Dr. Edmund Dever, for offering support, encour- agement, and guidance. I gratefully acknowledge the suggestions and support from OSU professors Dr. Burkan Isgor for information on concrete, and Dr. John Nabelek, Dr. Eric Kirby, and Dr. Andrew Meigs for personal talks about seismicity at faults. In pursuit of my teaching goals, I am thankful for Dr. Shane Brown for insightful suggestions, encouragement, and patience. I thank Dr. Jason Weiss for his support of teaching a tunnel course at OSU. I gratefully appreciate the financial support received towards my Ph.D. from the National Science Foundation Graduate Research Fellowship Program. I am also grateful to the funding received by the Jerry Yamamuro Geotechnical Fellow- ship. I am thankful to Connie and Lee Kearney for supporting Dr. Scott Ashford, who, in return, was able to support me. The informational support of six different tunnel companies in the U.S. is gratefully acknowledged. I am grateful to all of those, with whom I have had the pleasure to work during this and other related projects. During early stages of my research, I am thankful to Don Ballantyne who supported my research with his extensive knowledge and wisdom. I thank Dr. Armin Stuedlein for his support of the GIGSO group and the personal opportunity to organize a 2 days graduate student symposium at OSU. I thank the Kearney Hall office staff for their continuous support. I would like to express my sincere appreciation to Prof. Bray for a short but important personal talk at UC Berkeley and Prof. Arduino for a personal talk about OpenSees soil elements, 2D and 3D modeling. I appreciate their honesty. I would especially like to thank my friends at OSU, (almost there Dr.) Maggie Exton, Dr. Adriana Debora Piemonti, and all of the Owen grad office past and present, for their advice, opinion, moral support, willingness to listen, outdoor adventures, and friendship. Nobody has been more important to me in the pursuit of this Ph.D. than the members of my family. I thank you all for your love, support, and encouragement. I would like to thank my parents, Barbel¨ and Herbert Lange, my sister Kerstin, and my aunt and uncle, Tina and Benno Voß, for believing in me that whatever I want to do is achievable. Most importantly, I am so thankful to my loving husband Alan. I can‘t thank you enough for motivating and inspiring me throughout this experience, for your companionship, love, patience, constant emotional support, humongous understanding, and for making daily oatmeal and carrot-juice to keep le lait maternel running. I could never express my gratitude in words for you. I would like to express my love to my wonderful daughter Luciana, who provided unending inspiration and passion. I thank the trees (and recycled paper products) for their self-sacrifice that allows not only this thesis to be printed but also all the books, manuscripts, journals, and thank you - cards I used over the past half a decade. ***** Stephanie Lange Oregon State University May 2019 CONTRIBUTION OF AUTHORS Dr. Ben Mason assisted with earthquake engineering, formulating parameter ranges, the interpretation of data, and editing. Dr. Michael Scott was involved with the nu- merical modeling, the sensitivity analysis, the interpretation of data, and editing. Dr. Scott Ashford assisted with the overall research topic, research question find- ing, interpretation of data, and the application of the research results to an existing tunnel. TABLE OF CONTENTS Page 1 INTRODUCTION 1 2 ANALYSIS OF CONCRETE-LINED TUNNELS CROSSING ACTIVE FAULTS - BACKGROUND AND MODEL SET UP 5 2.1 Concentration on concrete structure . .5 2.1.1 Abstract . .5 2.1.2 Introduction . .6 2.1.3 Background . .8 2.1.4 Basic features of numerical model . 10 2.1.5 Preliminary results . 18 2.1.6 Conclusions .