Formwork development has paralleled the growth of concrete construction throughout the 20th century. In the last several decades formwork technology has become increasingly important in reducing overall costs, since the structural frame constitutes a large portion of the cost of a formwork system.
This book has three objectives. The first is to provide technical descriptions and evaluations of ten formwork systems that are currently used in concrete construction. The second is to serve as a tool to assist contractors in selecting the optimal formwork system. The third is to present the design criteria for conventional formwork for slabs and walls using the stress and the stress modification factors provided by the National Design Specifications (NDS) and the American Plywood Association (APA).
Following a comprehensive introductory chapter, five types of formwork systems for concrete slabs are presented in chapters 2-5. These are conventional wood forms, conventional metal forms, flying forms, the column-mounted shoring system, and tunnel forms. The last four chap-
ters describe five types of formwork systems for concrete columns and walls: conventional wood forms, ganged forms, jump forms, slip forms, and self-raising forms. Particular consideration is given to topics such as system components, typical work cycles, productivity, and the advantages and disadvantages associated with the use of various systems.
The selection of a formwork system is a critical decision with very serious implications. Due consideration must be given to such factors as the system’s productivity, safety, durability, and many other variables that may be specific to the site or job at hand. Chapters 5 and 9 provide a comparative analysis of forming systems for horizontal and vertical concrete work to facilitate the selection of the optimal forming system.
Existing formwork design literature is inconsistent with the design criteria for wood provided by the NDS and the APA. Chapters 3 and 7 provide a systematic approach for formwork design using the criteria of the American Concrete Institute committee 347-94, the NDS, and the APA. For international readers, metric conversion is provided in the Appendix.
This book is directed mainly toward construction management, construction engineering and management students, and concrete contractors. It may also serve as a useful text for a graduate course on concrete formwork, and should be useful for practicing engineers, architects, and researchers.
Awad S. Hanna