TABLE OF CONTENTS Robert T. Ratay, Ph.D., P.E.
To architects, engineers, lawyers, and even some contractors, temporary structures in construction are not as familiar as permanent structures, such as buildings and bridges. For the engineer to design effective, economical, and safe temporary access or support structures, he or she has to have an understanding of not only loads, strength, and stability; but also the business and practice of temporary works in order to know where, when, how, why, and by whom temporary works are used. For the forensic engineer to conduct an intelligent investigation of a construction failure involving temporary structures, she or he, too, has to have an understanding of not only loads, strength, and stability; but also the business and practice of temporary works in order to recognize the possible sources and nature of problems. Therefore, it was decided to devote much of this chapter to design philosophies, to an overview of the design-construction processes as they relate to temporary structures, and to the applicable design and construction codes, standards, and regulations. The rest of the chapter includes presentations of several case histories.
Disturbingly large numbers of structural failures during construction occur in the United States, as well as throughout the world. Advances in construction technology, newly developed materials, increasingly fine-tuned designs, and the construction of more daring structures, as well as the pressure of time- and cost-cutting driven by competition, are all contributing factors. But the most frequent direct causes of failures are human factors: oversight; carelessness;
