Copyright Warning Use of this thesis/dissertation/project is for the purpose of private study or scholarly research only. Users must comply with the Copyright Ordinance. Anyone who consults this thesis/dissertation/project is understood to recognise that its copyright rests with its author and that no part of it may be reproduced without the author’s prior written consent. CITY UNIVERSITY OF HONG KONG 香港城市大學 Scaffolding Systems in Hong Kong – Current Practice and Development Of MBMSS 香港棚架系統 – 竹通混合棚的現況及發展 Submitted to Department of Building and Construction 建築系 for the Degree of Engineering Doctorate 工程學博士學位 by So Yu Shing 蘇汝成 July 2009 二零零九年七月 Abstract Scaffolding is widely used in the construction industry. Traditional bamboo scaffolding has a long history and metal scaffolding has been in use for nearly 100 years. To meet safety requirements, address the problems involved in high rise building construction and take advantage of modern building technology, a new design scaffolding system has been invented. The Metal Bamboo Matrix Scaffolding System (MBMSS) takes advantage of the merits of both bamboo and metal scaffolding. Drawing support from academic research, and in conjunction with a standardised operational process and management protocol, MBMSS has been developed into a flexible scaffolding system that fulfils the requirements of various scenarios in the construction industry. The system has been patented in Europe, Hong Kong and China, and has been used in construction projects since 1998. The live load of MBMSS is less than metal scaffolding, and the new system has better safety features than bamboo scaffolding in terms of structural calculation and a standardised working environment. A new calculation approach, NAF-Nida, has been adopted, and safety has been further improved by considering the imperfection of alignment and deformation of the scaffold members; taking the nylon safety net vibration induced by wind into consideration, anchoring intervals and safety precautions during typhoons have also been reviewed. A modern operation and management scheme has also been developed to ensure the system‟s safety standards and address quality assurance and cost control. MBMSS is an integrated system and its performance has been proven by hundreds of projects implemented in actual environments and various working scenarios. Acknowledgements I wish first to thank my supervisor Professor S Kitipornchai for many discussions and thoughtful comments during my research and the preparation of this thesis. Although the idea presented in this thesis and the subsequent development of the MBMSS was my work alone, I benefited from the assistance and support of Mr Roger Lin, Mr Sunny Yau and Mr Stanley Lam of WLS Holdings Ltd. Finally, I would like to express my gratitude to the members of my family who offered their moral support during the years spent on this work, especially my wife, who has been a source of support in both happy and difficult moments. List of Content Abstract Acknowledgement Page Chapter 1 Introduction 1 Chapter 2 History of Scaffolding 4 2.1 Bamboo scaffolding 4 2.1.1 Training for building bamboo scaffolding 6 2.1.2 Changes in bamboo scaffolding 9 2.1.3 Current bamboo scaffolding 10 2.2 Metal scaffolding 14 2.3 Other work platforms 15 2.3.1 Mixed bamboo and metal scaffolding 15 2.3.2 Computerised self-climbing work platform 17 2.3.3 Gondolas 18 2.3.4 Mast climber work platform 22 Chapter 3 Configuration and Design of Traditional Scaffolding 23 3.1 Basic structural configuration 23 3.1.1 Bamboo scaffolding 23 3.1.2 Metal scaffolding 30 3.2 Legislation and codes of practice 33 3.2.1 Safety requirements for working on scaffolds 34 3.2.2 Loading requirement for scaffold 35 3.3 Research on scaffolding 39 3.3.1 Material properties 39 3.3.2 Full scale experimentation and simulation 42 Chapter 4 Design Philosophy 4.1 Advantages and Disadvantages of Traditional Scaffolding 47 4.1.1 Reasons for widespread use of bamboo scaffolding in the Hong Kong construction industry 48 4.1.2 Engineering problems associated with bamboo and metal scaffolding 50 4.2 The Need for Change 51 4.3 Design Specifications 62 4.3.1 Functional and safety requirements 62 4.3.2 Integrated scaffolding system 64 4.4 Metal Bamboo Matrix Scaffolding System (MBMSS) 65 Chapter 5 Implementation of MBMSS 5.1 From Theory to Reality 77 5.1.1 Patent application and registration 83 5.1.2 Support from other research 84 5.2 Operation and Management 95 5.2.1 Safety management 96 5.2.2 Operation management 104 5.3 Case Study Demonstrating Applications in Various Scenarios 120 5.3.1 Application of MBMSS to high rise building construction 120 5.3.2 Application of MBMSS to infrastructure works 130 5.3.3 Application of MBMSS to large scale internal renovations 139 Chapter 6 Discussion 6.1 Comparison of Safety, Cost, Operation and Application of the MBMSS with those of Traditional Scaffolding 147 6.1.1 Safety 147 6.1.2 Cost 151 6.1.3 Operation 156 6.1.4 Application 158 6.2 Comparison of the MBMSS with Other Forms of Metal Bamboo Scaffolding Systems in China 168 Chapter 7 Conclusion 7.1 Review of Major Findings 178 7.1.1 Major Achievement of MBMSS 178 7.1.2 Significant Improvement Adopted by Scaffolding Industry 180 7.1.3 Other Mixed Metal-Bamboo Scaffold in Hong Kong 182 7.2 Suggestions for Future Work 183 Reference 185 Appendices 192 List of Appendices A.3.1 Recommendation on Configuration of Bamboo Scaffolding (Code of Practice for Bamboo Scaffolding Safety 2001) A.3.2 Recommendation on Guidelines for the Design and Construction of Bamboo Scaffolds (2006) A.3.3 Recommendation on Configuration of Metal Scaffolding (Code of Practice for Metal Scaffolding Safety 2001) A.3.4 Frequency and total duration of display of tropical cyclone warning signals: 1956-2007 (Hong Kong Observatory) A.4.1 Bill of Materials for MBMSS A.4.2 The specification and inspection certificate of the steel tube A.4.3 Test Certificate of Catwalk A.5.1a Copy of Certificate of Grant of Patent for United Kingdom A.5.1b Copy of Certificate of Grant of Patent for Hong Kong A.5.1c Copy of Certificate of Grant of Patent for People Republic of China A.6.1 Summary of Maximum gust Peak Speeds and Maximum Hourly Mean Winds of Kammuri on 6 August 2008 (Hong Kong Observatory) A.6.2 Summary of Maximum Gust Peak Speeds and Maximum Hourly Mean Winds of Nuri on 22 August 2008 (Hong Kong Observatory) Chapter 1 Introduction Bamboo scaffolding has a long history. In the past 30 years it has been developed significantly and applied in many different applications. Metal scaffolding, in contrast, has only been used for 100 years, but there are now a number of different types of metal scaffolds. Despite the evolution of bamboo and metal scaffolding, recent concerns about safety, increasingly high buildings and operating cost and flexibility constraints have paved the way for the invention of a new scaffolding system. This study will introduce the current scaffolding system used in Hong Kong and the design, implementation of a new scaffolding system Metal-Bamboo Matrix System Scaffold (MBMSS) will be presented. Before the establishment of the Construction Industry Training Authority in 1976, scaffolder was trained by traditional apprentice-master approach, the training period was usually long and the progress was closely monitored by the master stage by stage. There is no unified training and the knowledge was always conveyed without any theory or a strong academic support. It can be understood that due to the material properties of natural bamboo, a systematic design of bamboo scaffold like the metal scaffold is not available. Despite a long history of bamboo scaffold, a systematic study was begun in 1981 by Janssen (1981). Since bamboo is a natural product, the material properties are not consistence and it is strong relied on the experience of the scaffolder to make judgement when carry out his work. Due to the constraints of the material properties, it is difficult to obtain a theoretical analysis of a bamboo scaffold. A full scale experiment and numerical simulation of bamboo scaffold were conducted by Chang & Yu (2002) and the deviation of these two results was about 30%. The author, a practitioner in bamboo scaffold, has a profound experience in the scaffold industry 1 and leading his own scaffold company, is able to share his experience and to test his idea in actual environment, to push forward the evolution of the bamboo scaffold into a new dimension. The objective of the research reported here was to design an integrated scaffolding system that could improve on the performance of bamboo scaffolding, but also maintain bamboo‟s good reputation as being cheap, flexible and efficient. The research drew support from academic studies in an attempt to ensure that the scaffolding system designed could be deployed in various scenarios. A management protocol was also established to ensure the system‟s safety and efficient operation. The scope of this research will review the current scaffold industry; the configuration of existing bamboo scaffold and the metal scaffold; the requirement of the building and construction industry as well as the legislation and regulation. Based on the advantage and disadvantage, a new scaffold system that could comply with the tightening legal requirements for bamboo scaffolding in Hong Kong will be designed. A key requirement was that the system had to be acceptable to Hong Kong‟s construction industry and take into account all current forms of malpractice. It had to be a system capable of eradicating all human error, wilful damage and inadequate workmanship.