Advanced analysis and reliability-based design of steel scaffolding systems

This thesis presents a comprehensive investigation of the advanced analysis, reliability-based design and optimisation of steel support scaffolding systems. Support scaffolding systems are used to provide temporary support to timber formwork systems, reinforcement, concrete, workmen and equipment, during the construction of permanent structures such as buildings and bridges. Stick-type steel scaffolds with cuplok joints are the focus of the thesis. This thesis includes the collection and statistical analysis of shore load effects occurring as a result of construction dead and live loads. A comprehensive series of U-head joint subassembly tests, allowed the top rotational stiffness to be rationally quantified for advanced finite element modelling. Advanced finite element models are calibrated using data compiled in a previous investigation involving eighteen full-scale tests. This calibration exercise also provides statistical data for modelling error. Monte Carlo simulations using advanced analysis are performed to determine the statistical distributions of system strength for a range of geometric configurations of support scaffold systems. The research showed that system strength was governed mainly by jack extension at the top and bottom of the scaffolding system. By incorporating the load statistics and system strength statistics, the thesis determined the reliability of various steel scaffolding systems designed by the fundamental Load-Resistance-Factor-Design (LRFD) equation. The study further proposed a more efficient LRFD equation for steel scaffolding, based on an acceptable target reliability index. Preface __________________________________________________________________ v ACKNOWLEDGEMENTS The research conducted as part of the following thesis was carried out at the Centre for Advanced Structural Engineering (CASE) located within The University of Sydney, Australia, under the supervision of Professor Kim Rasmussen and Dr Hao Zhang to whom I wish to express my most sincere appreciation and gratitude for their invaluable guidance, advice, encouragement and ongoing support throughout the entirety of this work. I would like to thank Acrow Formwork and Scaffolding staff members, Mr Hamid Pourbozorgi, Mr Ranji Premaratne and Mr Shahram Ebrahimian, for their advice and assistance in this research. I would also like to thank the CASE support staff, including Mr Gary Towell and Mr Brett Jones, who were instrumental in assisting in component tests. I would also like to acknowledge the efforts of my undergraduate research assistant, Mr Matthew Wells, for his involvement with the U-head component tests. I would like to thank the formwork managers, engineers, labourers and support staff that assisted in the two year long investigation of construction live and dead loads. Thanks must also go to my colleague and friend, Mr Adam Trouncer for his ongoing support and positive attitude during the last four years. On a personal level, I could not have completed this thesis without the loving support of my entire family, particularly my mother and father, Amanda and Michael and my sister, Anna. Their guidance, generosity, constant encouragement and support have been paramount to the success of this thesis, and I am truly grateful to have them in my life. I would also like to thank Mr Ross Clarke, Director of Enstruct Group, who has allowed me to be involved in the design of some landmark buildings across Australia. He has been instrumental to the completion of this PhD thesis; his personal encouragement, positivity and success have inspired me. Furthermore, his ongoing support of this thesis has been one of the most critical factors contributing to where I am today. I could not have asked for a better role model and personal mentor. Preface __________________________________________________________________ vi Financial support for this project was provided by Acrow Formwork and Scaffolding Pty Ltd, The University of Sydney Civil Engineering Foundation and the Australian Research Council. I would like to thank these organisations for their financial support of the project and scholarships including my Australian Postgraduate Award and Civil Engineering Foundation Supplementary Scholarship. Preface __________________________________________________________________ vii