Design Variables for Steel and Aluminium in High-Rise Rooftops
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Design Variables for Steel and Aluminium in High-Rise Rooftops A Thesis by George Nadim Melhem BMetEng (Hons), MSc MIE Aust, CPEng, NPER No. 1290572 Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Materials Science and Engineering School of Materials Science and Engineering Faculty of Science University of New South Wales July 2008 To my father Nadim Melhem, who inspired the writing of this thesis. (iii) (iv) (v) (vi) ACKNOWLEDGEMENTS I would like to thank my supervisor Professor C.C. Sorrell for his tolerance of my constantly changing direction of the thesis. He has guided and advised me so that I could take the journey and probe my way through the forest initially, before finally selecting the trees for this thesis. Professor Sorrell has been an immense source of inspiration for me. His editorial skills and efforts also are greatly appreciated. I am pleased to acknowledge the valuable assistance of Prof. A.G. Crosky, who kindly agreed to review the technical aspects of the metallurgical content of the thesis. I also would like to acknowledge and thank my co-supervisor Dr. S. Bandyopadhyay for his guidance and support. I wish to thank Qantas Airways Ltd., which has been the driving force behind setting the bar higher for my company Perfect Engineering Pty. Ltd., and in directing us to achieve several milestones and accreditations. These achievements have enabled my company to reach this point and to accomplish the end-result of this project. I also wish to acknowledge and thank Westfield Design & Construction Pty. Ltd. (Bondi Junction), which has had the confidence to select Perfect Engineering Pty. Ltd. as the engineering contractor to take on this mammoth but vital project, and also for the opportunity to undertake this research unreservedly. I would like to thank my team of engineers and managers who assisted with this project and stayed the course with my unconventional engineering methods and ideas. I especially would like to thank my mother Samia and my father Nadim. My mother taught me discipline at an early age and the value of hard work and integrity. She has sought tirelessly to instil in me the importance of giving without the expectation of return. My father taught me never to be afraid of taking calculated risks for worthwhile goals. He has instilled in me the importance of ethics and honesty. His motto is reflect, then action. Finally, I would like to thank my beautiful wife Eva, my two lovely daughters Ursula and Rhaneen, who intuitively understood what was required for this dissertation and hence unselfishly provided me with my space. We are expecting a newborn in the family toward the end of this work. I will not mind the noise now that I am done. My wife has provided me with encouragement and inspiration during the writing of this thesis, for which I am forever grateful. I now can spend time with all of you. (vii) ABSTRACT The present work is not a typical Doctoral thesis in Materials Science and Engineering in the sense that it surveys specific technical literature and reports on the outcomes of a series of experiments. This thesis reports a case study in the design and construction solutions for a major corrosion failure at the Westfield Tower 2, Bondi Junction. The contract was awarded to Perfect Engineering Pty. Ltd. (under my complete guidance) by Westfield Design & Construction Pty. Ltd. in early January 2005. Rectification work, largely on aluminium louvres and steel brackets on the roof and façade of levels 26-29, was completed in June 2005 and the installation has been monitored continuously since then. It must be noted that wherever Perfect Engineering Pty Ltd., appears in the text of this dissertation, the work has been undertaken, researched, designed and approved by me personally. However, Perfect Engineering Pty Ltd is my team and operates strictly under my complete guidance. The present work is divided into three discrete components: Section I Generic Information for the Profession (Chapters 1-3) Section II Field Investigation Technical Considerations (Chapters 4-8) Section III Figures and Appendices Generic Information for the Profession A significant part of the present work attempts to address what is perceived as a need for a document that offers an attempt at comprehensive guidance for the designer and engineer working on metallurgical corrosion issues in high-rise buildings. The approach taken has been to provide coverage of the full range of issues of relevance to professionals working in the field, including research, design, risk management, safety, project management, corporate governance, statutory requirements, compliance, finances, administration, etc. These aspects cover the full range of professional responsibilities incumbent on a company undertaking major construction work. On the technical side, the literature survey is targeted at the specific corrosion problems and their solutions: a) Types and effects of corrosion b) Aluminium as a structural material (viii) c) Riveting and welding of aluminium d) Galvanising of steel Perhaps the most innovative approaches to these materials issues are consideration of the following technologies: a) Use of aerospace materials technologies to inform the design, selection, and implementation of aluminium alloys, bolted, riveted and welded b) Preliminary investigation of factorial and matrix approaches for the assessment of life time and susceptibility to corrosion and welding in high-rise buildings Field Investigation Technical Considerations The field investigation reports on all phases of the actual rectification work, including before, during, and after. This material is described as follows: a) Chapter 4: Assessment of causes of failure of louvres and brackets, modifications to design of other structural members, rectification solutions b) Chapter 5: Exposition of the generic factorial approach for estimated service life of components c) Chapter 6: Application of matrix methods to the effects of corrosion and welding d) Chapter 7: Manual calculations of applied stresses and finite element modelling of the same e) Chapter 8: Summary discussion of all relevant issues Ultimately, the aims of the present work were as follows: a) Consideration of the roles and responsibilities of designer and engineer b) Examination of novel design solutions that answered specific problems that had to be solved under stringent constraints d) Undertaking of stress calculations for all components to ensure that the requirements of general design principles were satisfied e) Confirmation of the stress calculations through finite element modelling f) Careful examination of all materials issues such that further structural degradation and corrosion damage would not re-occur g) Additional critical consideration of relevant environmental effects on the materials, including the potential effects of water, salt, and wind. f) Implementation of these design solutions using aerospace materials and methods (ix) g) Attempt to predict future performance through generic factorial approach and specific matrix method approaches Outcomes a) It is hoped that Chapters 1-3 and the associated following text will provide a documentary basis for future guidance of designers and engineers working in areas related to the subject of the present work. To the author’s knowledge, such a compendium of issues and considerations has not been prepared before. b) It also is hoped that the work on aerospace technologies will broaden the scope of designers and engineers in the potential that these materials and processes have in building considerations. The results of the engineering solutions developed by me personally and my team amply demonstrate the success of these approaches. c) The manual stress calculations and finite element modelling confirm that the implemented designs are consistently within design specification and that, from the mechanical perspective, no problems are anticipated. To date, further inspections of Westfield Tower 2 bear out this expectation. d) Further, since considerable care was taken to ensure that galvanic and other forms of corrosion were avoided through the appropriate use of design, materials, and implementation approaches, no further corrosion has been observed at the site. This is in considerable contrast to the situation that I had perceived personally observed upon commencement of the project. e) Application of a generic factorial approach and a specific matrix method, applied to corrosion and welding considerations, were informative but are considered still to be at a speculative stage owing to the difficulty of obtaining relevant meaningful data and the problem of assigning weighting factors on what is considered to be a fairly subjective basis. (x) PREFACE The present work is a culmination of over 20 years of experience in the engineering field, particularly metallurgical engineering. I graduated with my Bachelor’s degree in Metallurgical Engineering (Honours) in 1990, with the thesis Effect of Processing on Performance of Continuous Fibre Reinforced Plastic Composites. I completed a Master of Science degree 1996, with the thesis A Study of Abrasive Wear in SiC and Al2O3 Particulate Reinforced Composites. Both degrees were obtained from the School of Materials Science and Engineering, University of New South Wales. My career path has been oriented around research in metals of a diverse range, particularly secondary processing, with major companies including: a) Bradken Consolidated R&D: Worked in research and development (R&D) of materials used in defence equipment castings. b) BTR Engineering: Managed a team of engineers in R&D in the optimisation of heat treatment processes of metal transmission components and the evaluation of failure claims of vehicle components for Ford and Holden. Managed certain key projects for key clients in quality improvement processes for new prototypes. c) Monroe Springs: Managed a team of engineers in R&D in improvements in Mercedes, SAAB, Ford, and Holden coil and leaf spring design life and serviceability. Held additional position of Manager for the implementation of new quality systems in compliance with QS 9000 and ISO 9001:2000 for all processes.