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Framework for the Strategic Management of Dimensional Variability of Structures in Modular Construction

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Framework for the Strategic Management of Dimensional Variability of Structures in Modular Construction Framework for the Strategic Management of Dimensional Variability of Structures in Modular Construction by Christopher Rausch A thesis presented to the University of Waterloo in the fulfillment of the thesis requirement for the degree of Master of Applied Science in Civil Engineering Waterloo, Ontario, Canada, 2016 © Christopher Rausch 2016 Author’s Declaration I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii Abstract Challenges in construction related to dimensional variability exist because producing components and assemblies that have perfect compliance to dimensions and geometry specified in a design is simply not feasible. The construction industry has traditionally adopted tolerances as a way of mitigating these challenges. But what happens when tolerances are not appropriate for managing dimensional variability? In applications requiring very precise dimensional coordination, such as in modular construction, the use of conventional tolerances is frequently insufficient for managing the impacts of dimensional variability. This is evident from the literature and numerous industry examples. Often, there is a lack of properly understanding the rationale behind tolerances and about how to derive case specific allowances. Literature surrounding the use of tolerances in construction indicates that dimensional variability is often approached in a trial and error manner, waiting for conflicts and challenges to first arise, before developing appropriate solutions. While this is time consuming, non-risk averse, prone to extensive rework and very costly in conventional construction, these issues only intensify in modular construction due to the accumulation of dimensional variability, the geometric complexity of modules, and discrepancy between module production precision and project site dimensional precision. This all points to a need for a systematic and strategic approach for managing dimensional variability in modular construction. This thesis explores dimensional variability management from a holistic construction lifecycle viewpoint, examining key project stages (manufacture, fabrication, aggregation, handling, transportation and erection) to identify critical variability sources and proposing adequate strategies to control dimensional variability. The scope of this work relates primarily to the structural system of commercial building modules, based on the assumption that the sequence of production and dimensional variability of building subsystems (mechanical, electrical, plumbing, architectural) hinge upon the dimensional variability of the structure. A novel method for quantifying dimensional variability is developed, which uses 3D imaging by way of laser scanning and building information models to compute deviations between the intent of a geometric design and the actual as-built construction. Novel strategies for managing dimensional variability are also developed, and include adaptation of manufacturing-based principles and practices for use in construction systems. The inspiration and foundation of these new strategies is derived from the original research of Dr. Colin Milberg, who explored how to apply tolerance theory used in manufacturing into civil construction systems. The new techniques developed in this thesis, along with other previous research, demonstrate that there is a clear correlation between manufacturing industries such as aerospace and automotive assembly production, and that of modular construction assembly production. In light of this, there is an opportunity to improve modular construction processes if these manufacturing-based methods can be appropriately implemented. This is the basis for the proposed methodology presented in this thesis. Application of the proposed methodology using case study examples demonstrates that dimensional variability in modular construction should be approached from a holistic viewpoint. Furthermore, it needs to incorporate much more consideration into the key factors and critical sources of variability rather than pursuing the traditional construction approach of developing inefficient trial and error solutions. iii Acknowledgements I would like to acknowledge the funding sources of this research: the Natural Sciences and Engineering Research Council (NSERC), PCL-Permanent Modular Construction, and the Queen Elizabeth II Graduate Scholarship in Science and Technology (QEII-GSST) program. Throughout my studies at the University of Waterloo, the mentoring and support of my supervisors Dr. Jeffrey West and Dr. Carl Haas have shaped me into who I am today as a researcher, a professional and as a balanced individual. Dr. West has taught me how to approach a technical problem with a level of rigor, thoroughness, and precision that leaves no doubt in the methodical development of a solution. Dr. Haas has taught me how to set effective goals, how to map out the best pathway to these goals, and how to effectively use all available resources to ensure a foolproof journey to reach these goals. Outside of work, both Dr. West and Dr. Haas have also demonstrated how to be a disciplined and balanced individual: Dr. West by showing me how to set personal best times on the mountain bike, and Dr. Haas by showing me how to embrace my surrounding environment on cross country skis. The amount of time, guidance and support from Dr. West and Dr. Haas is unlike any shown to me in my career. For this I am very grateful. I want to acknowledge two of my biggest mentors Dr. Scott Walbridge, and Dr. Reinhold Schuster: Dr. Walbridge for your technical support and involvement in the Waterloo Steel Bridge Design Team and Dr. Schuster for your valuable career advice and for sparking my love of road biking. I want to thank Terry Ridgway and Richard Morrison for their numerous hours of support, and the great conversations we’ve had throughout my research. My development as an academic has probably been most notably shaped on a day-to-day basis by Dr. Mohammad Nahangi. I can’t count the number of hours Mohammad has taken out of his schedule to help me, and given enough time that might also be said about the number of articles and papers we could publish. We work great as a team, and I am very grateful for his direction, and for giving me the freedom to grow, develop and contribute my own ideas. Thomas Czerniawski, one of my best friends, has always challenged me to ask why, to never erase a thought I have written down but rather determine its relation to the infinite expanse of the universe, and to be relentless in the pursuit of a goal. I want to thank the many members of the research partner of this work (PCL-Permanent Modular Construction) who have helped me to formulate ideas, provide me with valuable feedback and to assist me with data collection: Mark Taylor, Matthew Scott, Ryan Clancy, Walter Schachtschneider, Clifford Mark, Pia Thurlow, and many others. I also want to acknowledge the support of many Waterloo students who have helped me throughout my research, whether through data collection, crunching numbers, giving me advice or by being a great teammate: Mohammed Enshassi, Melanie Perreault, Mohammad-Mahdi Sharif, Benjamin Sanchez, Ali Sabet, Junmeng Liu, Daniel Lahey and Lichen Zhang. I also want to acknowledge my family and friends. Without the love, support and spiritual guidance of my parents, I wouldn’t be where I am today. My friends have always been there to support me and to help me realize that life is much bigger than the length of a thesis. My love, Emily, has seen me in my most stressful of moments, but has still stuck by my side. For that I can’t begin to express my gratitude and love for her. Most importantly, I want to acknowledge my creator and savior Jesus Christ. From shaping the earth in which I live in, to formulating and perfecting the physical laws that govern the way in which we as humans can create the many things found in our everyday lives, you truly are the reason for me completing this thesis. I have only begun to scratch the surface of who you are, and I want nothing more than to discover your plan for my life as I continue to follow your lead, wherever you take me. iv Table of Contents Author’s Declaration .................................................................................................................................................... ii Abstract........................................................................................................................................................................ iii Acknowledgements ......................................................................................................................................................iv Table of Contents........................................................................................................................................................... v List of Figures ............................................................................................................................................................. vii List of Tables ................................................................................................................................................................xi 1. Introduction ..........................................................................................................................................................
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