Reinforced Concrete Design of Tall Buildings

Abstract

As I refl ect on my career as a practicing engineer, I am struck by the profound conceptual and methodological changes that computer-enhanced design has brought to our fi eld. Today, and especially in the last decade or so of computer use and software engineering, we can develop numerical solutions to an astonishing number of decimals with a degree of precision that was previously unfathomable. On account of liability issues, engineering innovations these days must also be analytically proven and strenuously tested to an extent unknown in the past. In spite of these concerns, the art of being able to smell or feel a reasonable solution must necessarily continue to exist. Without such intuition and creativity, we might tend to rely on computer applications as engineering itself, instead of as a necessary tool. As structural engineers, our primary task is to take someone else’s vision of a project, convert it into analytical and numerical models, and then produce a set of buildable documents. However, the current trend in engineering education seems to focus more on the behavior of computer-based mathematical models while seldom acknowledging their fallibilities. Given this scenario, one may wonder if the era of engineers who endorsed structural attitudes based on their qualitative knowledge of the behavior of the structures is gone. There is no doubt that navigating complicated software is certainly a critical and necessary part of a designer’s vocabulary. My sense, however, is that such skills would be more powerful, accurate, and useful if built upon a solid foundation of engineering principles and conceptual knowledge. I am not alone in voicing these ideas; a plethora of recently published journal articles, opinion pieces, and conference presentations address this ever-increasing gap between the conceptual approach and the scientifi c illusion created by computer solutions. These thoughts occur to me in my day-to-day engineering and more specifi cally as I was preparing this manuscript. Therefore, the challenge I set for myself in this book was to bridge these two approaches: one that was based on intuitive skill and experience, and the other that relied on computer skills. Imagine then the design possibilities when experiential intuition marries unfathomable precision and numerical accuracy. Engineers are generally characterized as imaginative in their design approach as supported by historical evidence, which includes the creation of ancient structures, medieval cathedrals, and the skyscrapers of today. None of these structures, except for those built in the last decade, were developed using intense calculations as we know them today, but were more products of inventive imagery. Even with the availability of immense analytical backup, imaginative thinking can and must be effectively used to apply basic concepts to complex problems. Therefore, the stimulus for writing this book was to develop imaginative approaches by examples, and, where appropriate, relate these