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Abstract This paper aims to develop an improved understanding of the critical response of structures to multicomponent seismic motion characterized by three uncorrelated components that are defined along its principal axes: two horizontal and the vertical component. An explicit formula, convenient for code applications, has been derived to calculate the critical value of structural response to the two principal horizontal components acting along any incident angle with respect to the structural axes, and the vertical component of ground motion. The critical response is defined as the largest value of response for all possible incident angles. The ratio r cr/ r srss between the critical value of response and the SRSS response—corresponding to the principal components of ground acceleration applied along the structure axes—is shown to depend on three dimensionless parameters: the spectrum intensity ratio between the two principal components of horizontal ground motion characterized by design spectra A( T n) and A( T n); the correlation coefficient of responses r x and r y due to design spectrum A( T n) applied in the x- and y-directions, respectively; and β = r y/ r x. It is demonstrated that the ratio r cr/ r srss is bounded by 1 and. Thus the largest value of the ratio is, 1.26, 1.13 and 1.08 for = 0, 0.5, 0.75 and 0.85, respectively.
This implies that the critical response never exceeds times the result of the SRSS analysis, and this ratio is about 1.13 for typical values of, say 0.75. The correlation coefficient depends on the structural properties but is always bounded between −1 and 1. For a fixed value of, the ratio r cr/ r srss is largest if β = 1 and = ±1. The parametric variations presented for one-storey buildings indicate that this condition can be satisfied by axial forces in columns of symmetric-plan buildings or can be approximated by lateral displacements in resisting elements of unsymmetrical-plan buildings. Copyright © 2000 John Wiley & Sons, Ltd.
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Description Designed for senior-level and graduate courses in Dynamics of Structures and Earthquake Engineering. Dynamics of Structures includes many topics encompassing the theory of structural dynamics and the application of this theory regarding earthquake analysis, response, and design of structures. No prior knowledge of structural dynamics is assumed and the manner of presentation is sufficiently detailed and integrated, to make the book suitable for self-study by students and professional engineers.
• Section on application of the inelastic design spectrum to structural design – For allowable ductility, seismic evaluation of existing structures, and displacement-based structural design. • Examples on dynamics of bridges and their earthquake response. • Incorporation of three building codes and inclusion of the Eurocode. • Theory of dynamic response of structures – Presented in a manner that emphasizes physical insight into the analytical procedures. • Structural dynamics theory – Applied to conduct parametric studies that bring out several fundamental issues in the earthquake response and design of multistory buildings. • Analytical procedures – Illustrated by over 100 worked out examples.
• Over 400 figures carefully designed and executed to be pedagogically effective. • Photographs of structures and their responses recorded during earthquakes – Included to relate the presentation to the real world. Dynamics of Structures has been well received in the 16 years since it was first published. It continues to be used as a textbook at universities in the United States and many other countries, and enjoys a wide professional readership as well. Translations in Japanese, Korean, Chinese, Greek, and Persian have been published. Preparation of the fourth edition provided the author with an opportunity to improve, expand, and update the book.
Chapter 14 has been added, requiring renumbering of Chapters 14 to 22 as 15 to 23 (the new numbering is reflected in the Preface); Chapters 5 and 16 underwent extensive revision; Chapters 12 and 13 have been expanded; and Chapters 22 and 23 have been updated. Specific changes include: • Chapter 14 on nonclassically damped systems has been added. This addition has been motivated by growing interest in such systems that arise in several practical situations: for example, structures with supplemental energy-dissipating systems or on a base isolation system, soil–structure systems, and fluid-structure systems.
• Chapters 5 and 16 on numerical evaluation of dynamic response have been rewritten to conform with the ways these numerical methods are usually implemented in computer software, and to offer an integrated presentation of nonlinear static analysis—also known as pushover analysis—and nonlinear dynamic analysis. • A section has been added at the end of Chapter 12 to present a general version of the mode acceleration superposition method for more complex excitations, such as wave forces on offshore drilling platforms. • Chapter 13 has been extended to include two topics that so far have been confined to the research literature, but are of practical interest: (1) combining peak responses of a structure to individual translational components of ground motion to estimate its peak response to multicomponent excitation; and (2) response spectrumbased equations to determine an envelope that bounds the joint response trajectory of all simultaneously acting forces that control the seismic design of a structural element. Windows Server 2003 Standard R2 64 Bit Iso Download. • Chapters 22 and 23 have been updated to reflect the current editions of building codes for designing new buildings, and of performance-based guidelines and standards for evaluating existing buildings. • The addition of Chapter 14 prompted minor revision of Chapters 2, 4, 6, 10, and 12. • Several new figures, photographs, worked-out examples, and end-of-chapter problems have been added. • Using the book in his teaching and reflecting on it over the years, suggested improvements for the author.