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Cob Property Analysis Gabi Brunello Santa Clara University Santa Clara University Scholar Commons Civil Engineering Senior Theses Engineering Senior Theses Spring 2018 Cob Property Analysis Gabi Brunello Santa Clara University Jose Espinoza Santa Clara University Alex Golitz Santa Clara University Follow this and additional works at: https://scholarcommons.scu.edu/ceng_senior Part of the Civil and Environmental Engineering Commons Recommended Citation Brunello, Gabi; Espinoza, Jose; and Golitz, Alex, "Cob Property Analysis" (2018). Civil Engineering Senior Theses. 67. https://scholarcommons.scu.edu/ceng_senior/67 This Thesis is brought to you for free and open access by the Engineering Senior Theses at Scholar Commons. It has been accepted for inclusion in Civil Engineering Senior Theses by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. R S H 6 13.2018 COB PROPERTY ANALYSIS by Gabi Brunello Jose Espinoza & Alex Golitz SENIOR DESIGN PROJECT REPORT submitted to the Department of Civil Engineering of Santa Clara University in partial fulfillment of the requirements for the degree of Bachelor of Science in Civil Engineering Santa Clara, California Spring 2018 ii Acknowledgements A special thank you: Dr. Tonya Nilsson Dr. Mark Aschheim Brent Woodcock The Members of COB Research Institute (CRI) For their overwhelming contributions and guidance in assisting this project, developing the field of study, and pushing the students to achieve ever greater knowledge to create a more sustainable future. iii COB Property Analysis Gabi Brunello, Jose Espinoza and Alex Golitz Department of Civil Engineering Santa Clara University, Spring 2018 Abstract The goal of this project was to research the material properties of the green building material COB in order to better understand how to apply COB in real world applications. The research portion included soil analysis, compression, modulus of rupture and elasticity tests, hydrometer analysis, and atterberg limits tests. Additionally, through a partnership with the professionals of the COB Research Institute team and another COB-centric senior design group, this team was able to produce the first full-scale wall tests for COB. Four 7-foot walls were constructed and in-plane lateral cyclic loading was applied to create the effects of a COB structure under lateral loading. The results of the full-scale tests are in the process of being incorporated in the entry for COB into the California Residential Code, with a recommendation given for the reinforcing design that performed the best, through allowable load and deflection calculations. Finally, the team used a sample footprint for a simple house to develop structural house components for a COB structure that could benefit COB application in the real world. The simulated application of COB is helping the COB Research Institute formulate their submittal and ultimately provide a jumping off point for further research of this nature. The ultimate goal was to spread awareness of sustainable building practices and make them more accessible to the general public. iv Table of Contents Certificate of Approval………………………...…………………………………………………..i Title Page………………………………………………………………………………………….ii Acknowledgement………………………………………………………………………………..iii Abstract…………………………………………………………………………………………...iv Table of Contents………………………………………………………………………………….v List of Figures…………………………………………………………………………………….vi List of Tables…………………………………………………………………………………….vii Introduction………………………………………………………………………………………..1 Demonstrated Need for Project…………………………………………………….……………...3 Problem Statement………………………………………………………………………………...4 General Site Details…………………………………………………………………………….....4 Project Scope………………………………………………………………….…………….….....4 Analysis of Alternatives…………………………………………………………………………..5 Alternative Solutions…………………………………………………………...…………5 Comparison of Alternatives……………………………………………………………………....6 Technical Feasibility……………………………………………………………………...6 Cost……………………………………………………………………………………….7 Environmental Impact…………………………………………………………………....7 Capacity…………………………………………………………………………………..8 Selection Logic…………………………………………………………………………...8 Design Criteria and Standards……………………………………………………………....…....8 Description of Designated Facility…………………………………………………………….....9 Design Approach…………………………………………………………………….…...9 Innovations……………………………………………………………………………………….13 Mix Design Research…………………………………………………………………….13 Similar Material Research………………………………………………………………..14 Wall Design and Connection Research…………………………………………………..15 Patents…………………………………………………………………………………....16 Problems…………………………………………………………………………………………16 Challenges with the Technology…………………………………………………………16 Permitting, Political and Safety Issues…………………………………………………...17 Environmental Impacts…………………………………………………………………..17 Results……………………………………………………………………………………………18 Soil Test………………………………………………………………………………….18 Small Scale Test………………………………………………………………………….21 Full-Scale Wall Test…………………………………………...………………………...25 Analysis…………………………………………………………………………………………..30 R-Value……………………………………………………………………....…………………..32 Design Component……………………………………………………………………………….34 v Wall to Wall Connection………………………………...………………………………35 Roof to Wall Connection………………………………………………………………...39 Window and Door Openings……………………………………...……………………..42 Cost Estimate…………………………………………………………………………………….44 Probable Cost…………………………………………………………………………….44 Assumptions……………………………………………………………………………...45 Conclusion…………………………………………………………………………………….....46 References………………………………………………………………………………………..47 Appendices……………………………………………………………….………………………49 Wall to Wall Connection Calculations……………………………………………...….A-1 Roof to Wall Connection Calculations………………………………………………....B-1 Door and Window Opening Calculations………………………………………………C-1 vi List of Figures Medium Design COB Wall……………………………………………………………..…Figure 1 Floor Plan for Proposed Simple COB Structure………………………………...………...Figure 2 Common Practice Wall……………………………………….………………………...…Figure 3 Medium Design Wall 1.25:1 Aspect Ratio……………………………………….…….…Figure 4 Medium Design Wall 2:1 Aspect Ratio……………………………………….………..…Figure 5 Heavily Reinforced Wall…………………………………………………………….….…Figure 6 Grain Size Distribution ………………………………..…………………………….……Figure 7 Distribution of Fines……………………………………….…………………………..…..Figure 8 Number of Blows vs. Moisture Content….…………………………………………..……Figure 9 Modulus of Rupture Set-up....………………………………………………………........Figure 10 Three-Month Drying Period Beam Failure…...………………………………….….…...Figure 11 Common Practice Wall Post-Testing………………………………………………….…Figure 12 Hysteresis curve for Medium Reinforced wall (1.25:1).………………………….…...…Figure 13 Medium Reinforced Wall (1.25:1) Aspect Post-Testing…….…………………….……..Figure 14 Hysteresis curve for Medium Reinforced Wall (2:1)……………………….………..…..Figure 15 Medium Reinforced Wall (2:1) Aspect Post-Testing….…………………….…….……..Figure 16 Hysteresis curve for Heavily Reinforced Wall (2:1)..………………………………........Figure 17 Heavily Reinforced Wall (2:1) Aspect Post-Testing….……….……………………..…..Figure 18 Envelope Curves for (1.25:1) Ratio Medium Reinforced Wall………………….......…..Figure 19 Final Envelope Curve for Each Wall……..…………………………………………........Figure 20 Envelope Curves with Lateral Resistance in pfl…………….………………………........Figure 21 APA 158 Method for Wall 3………………………………………………......……..…..Figure 22 Wall to Wall Connection Design…………………………………………………..……..Figure 23 Shear Load Distribution in the COB Walls...………………………………….................Figure 24 Final Roof to Wall Connection Design………………......................................................Figure 25 Shearing between COB and Anchors during Common Practice Wall Test……………...Figure 26 Final Door and Window Opening………………..............................................................Figure 27 vii List of Tables Relevant Building Codes…………………………………………………………………...Table 1 Percent Weight of Straw……………………………………………………..……………..Table 2 Small-Scale Testing Results…………………………………………………………...…...Table 3 Calculated and Adjusted R-Values using APA 158 Method...………………………...…...Table 4 Project Budget by Item…………………………………………………………………......Table 5 viii Introduction The goal of this project was to work alongside the COB Research Institute (CRI) team; Anthony Dente, Massey Burke, and John Fordice, to help legitimize the use of COB structures in the California Residential Code. By advancing COB research and understanding its material properties in the United States, COB can be incorporated in building codes, and construction can be introduced globally. In COB construction, materials to build a structure are supplied locally because COB building incorporates the use of natural materials. Developing nations do not have the means to construct with typical materials found in the United States, such as steel and concrete. It is therefore important to provide them with reliable buildings made with less expensive materials. This team brought further attention to COB in the United States by conducting novel tests and delving further into the research of this material. Together with another COB senior design group, the teams built four different COB walls. These four walls included the common practice, medium design 1.25:1 aspect ratio, medium design 2:1 aspect ratio, and heavily reinforced walls with a height of seven feet and a 16-inch thickness. The common practice wall represents current building methods that can be found in the field, which includes a foundation connection of rigid rocks and no added steel reinforcement. The medium design wall uses only minimal rebar reinforcement at the bottom and top of the wall, and it also
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