Low Carbon Pathways for Structural Design: Embodied Life Cycle Impacts of Building Structures by Catherine De Wolf B.Sc., M.Sc. in Civil Architectural Engineering Vrije Universiteit Brussel and Université Libre de Bruxelles, 2012 M.Sc. in Architecture: Building Technology Massachusetts Institute of Technology, 2014 Submitted to the Department of Architecture in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Architecture: Building Technology at the Massachusetts Institute of Technology June 2017 © 2017 Catherine De Wolf. All rights reserved. The author hereby grants to MIT permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part in any medium now known or hereafter created. Signature of Author: Department of Architecture May 5, 2017 Certified by: John A. Ochsendorf Class of 1942 Professor of Architecture and Civil and Environmental Engineering Thesis Supervisor Accepted by: Sheila Kennedy Professor of Architecture Chair of the Department Committee on Graduate Students 2 Dissertation Committee John A. Ochsendorf Class of 1942 Professor Department of Architecture Department of Civil and Environmental Engineering Massachusetts Institute of Technology (MIT) Thesis Supervisor John E. Fernández Professor of Architecture Director of MIT Environmental Solutions Initiative MIT Thesis Reader Caitlin Mueller Assistant Professor of Architecture and Civil and Environmental Engineering MIT Thesis Reader Kathrina Simonen Associate Professor Department of Architecture University of Washington Thesis Reader 3 4 Low Carbon Pathways for Structural Design: Embodied Life Cycle Impacts of Building Structures by Catherine De Wolf Submitted to the Department of Architecture on May 5, 2017 in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Architecture: Building Technology ABSTRACT Whole life cycle emissions of buildings include not only operational carbon due to their use phase, but also embodied carbon due to the rest of their life cycle: material extraction, transport to the site, construction, and demolition. With ongoing population growth and increasing urbanization, decreasing immediate and irreversible embodied carbon emissions is imperative. With feedback from a wide range of stakeholders – architects, structural engineers, policy makers, rating-scheme developers, this research presents an integrated assessment approach to compare embodied life cycle impacts of building structures. Existing literature indicates that there is an urgent need for benchmarking the embodied carbon of building structures. To remediate this, a rigorous and transparent methodology is presented on multiple scales. On the material scale, a comparative analysis defines reliable Embodied Carbon Coefficients (ECC, expressed in kgCO2e/kg) for the structural materials concrete, steel, and timber. On the structural scale, data analysis evaluates the Structural Material Quantities (SMQ, expressed in kg/m2) and the embodied carbon for existing 2 building structures (expressed in kgCO2e/m ). An interactive database of building projects is created in close collaboration with leading structural design firms worldwide. Results show 2 that typical buildings range between 200 and 550 kgCO2e/m on average, but these results can vary widely dependent on structural systems, height, size, etc. On the urban scale, an urban modeling method to simulate the embodied carbon of neighborhoods is proposed and applied to a Middle Eastern case study. A series of extreme low carbon case studies are analyzed. Results demonstrate that a novel 2 design approach can lead to buildings with an embodied carbon as low as 30 kgCO2e/m , which is an order of magnitude lower than conventional building structures today. Two pathways are implemented to lower the embodied carbon of structures: choosing low carbon materials (low ECC) and optimizing the structural efficiency of buildings (low SMQ). This research recommends new pathways for low carbon structural design, crucial for lowering carbon emissions in the built environment. Thesis Supervisor: John A. Ochsendorf Title: Professor of Architecture and Civil and Environmental Engineering 5 6 ACKNOWLEDGMENTS First, I am tremendously thankful to my advisor, Prof. John Ochsendorf, for his high expectations, guidance, and friendship during my doctoral research at MIT. This dissertation would not have been possible without his creative vision and insightful mentoring. Particularly, I would like to thank Prof. Ochsendorf for his expertise and experience in research on structural design, his inspiring support since we started collaborating, and his enthusiasm for low carbon structures. He has taught me innumerable lessons on the workings of academia in general and set an example I hope to follow in my further work. This dissertation has also been greatly improved thanks to the very valuable feedback from my committee members. I thank Prof. John Fernández for offering me the opportunity to collaborate with researchers and policy makers worldwide, especially in Africa during the urban metabolism workshop in 2015, and for his knowledge on material flows and environmental impacts. I thank Prof. Caitlin Mueller for giving her time for helping me improve my research results and presentations, and for mentoring and inspiring me since I arrived at MIT. I thank Prof. Kathrina Simonen (University of Washington) for generously inviting me to implement my research results on a large scale in industry and for her knowledge and wisdom in embodied carbon of buildings. In addition to their individual inputs, I greatly appreciate my committee meeting’s generous and encouraging help. My highest appreciation also goes to Prof. Kathrina Simonen for inviting me to lead the Structural Engineers 2050 (SE 2050) Commitment Initiative with her and to Frances Yang, Eric Borchers, Victoria Valencia, Lauren Wingo (Arup) as well as Amy Hattan, Duncan Cox, and Elsa Mullin (Thornton Tomasetti) for their continuous feedback on developing the database of embodied Quantity outputs (deQo). I also would like to thank Arup and Thornton Tomasetti for contributing data to deQo. The methods and data structure were developed with input from the Carbon Leadership Forum in order to align with the SE 2050 Commitment Initiative. I am also grateful to Barbara Rodriguez Droguett (University of Washington), Erin McDade (Architecture 2030) and Prof. Wil Srubar (University of Colorado Boulder) for their help developing the implementation of the results from deQo. My thanks also go to Matt Bowick and Jennifer O’Connor (Athena Sustainable Materials Institute) for their feedback. I thank Eleanor Pence for helping me set up the backbone of deQo and introducing me to Django. The precious contributions of Serena Li, Margaret Wang, Dan Reynolds, and Jérôme Laforge for the development of deQo helped bring the database to completion. My special gratitude goes to Dr. Alice Moncaster and Dr. Francesco Pomponi for their advice, enthusiasm, and friendship during my research stay at the University of Cambridge. As part of the Whole Life Carbon in Buildings project, I was also honored to collaborate with experts in embodied carbon assessment in the United Kingdom, including Simon Sturgis, Athina Papakosta (Sturgis Carbon Profiling) Guy Battle, Henna Jain, Peter Armitage (Sustainable Business Parntership), Adam Locke, Susan Hone-Brookes (Laing O’Rourke), James Fiske, Alan Cripps, Ellie Scott (RICS), Emma Gains, Carlos Garcia Gonzalo, Sean Lockie (Faithfull + Gould), Kristian Steele, Daniel Roe (Arup), Sarah Beattie, Edward Dixon (LandSecurities), Natalia Ford (UKGBC), and Andrea Charlson (High Speed Two). 7 Moreover, I am very grateful to Prof. Christoph Reinhart for his help on the urban scale and applications of my work to real cities in Kuwait. This research was conducted as part of the Kuwait-MIT signature project on sustainability of Kuwait’s built environment under the direction of Prof. Oral Buyukozturk. I am very thankful to Carlos Cerezo for his involvement in the operational energy simulations and to Dr. Zainab Murthadhawi, Dr. Ali Hajiah, and Dr. Adil Al Mumin for sharing data on the neighborhood in Kuwait. For their help in the work towards this dissertation, I am thankful in particular to the following researchers: Wesley K. Lau, Dr. Ornella Iuorio, Prof. Elsa Olivetti, and Prof. Tim Gutowski for their help on the embodied carbon of structural materials; Kenny Verbeeck and Laurent Ney (Ney + Partners) for inviting me to conduct research on the embodied carbon of their bridges; Rosalie Bianquis, Julia Hogroian, Tess Hegarty, Andrew-James Unander, and Brenda Stern for their research work on material quantity optimization; Prof. Philippe Block and Dr. Tomas Mendez (ETH Zurich) for inviting me to collaborate on the embodied carbon of their visionary design projects; Alistair Gould and Kristian Bird (Helionix Designs) for sharing data and collaborating on the embodied carbon of exemplary case studies; Prof. Leon Glicksman and Prof. Les Norford for their support; and Prof. Corentin Fivet (EPFL) for his vision on future work. Furthermore, I am very thankful to Kathleen Ross for her help in administration and travels, to Marilyn Levine for correcting my writing, and to Duncan Kincaid for solving my computer troubles. Their continuous kindness and competence have enhanced my work and life on many occasions over the years. This research was sponsored by the MIT Presidential fellowship, the World