Calculation of Seismic Actions for Structural Analysis

Inhaltsverzeichnis

1. Frontmatter

2. Chapter 1. Seismology and Earthquakes

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   This chapter introduces the fundamental concepts and parameters of earthquakes, such as seismic waves and magnitude. These provide the foundation for understanding the approaches used to define seismic actions throughout this book. The physical and mathematical description of body and surface wave propagation forms the basis for seismic analyses of soil and structures, while magnitude serves as the most universal and widely recognized measure of an earthquake.

3. Chapter 2. Elastic Response Spectrum

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   The elastic response spectrum method is provided in all national and international codes, making it the primary approach for designing buildings, civil works, and industrial structures worldwide. Although relatively simple to apply, it requires careful calculation of certain parameters. This chapter details the parameters and procedures of spectral response (both general and code-specific) which are often not directly explained in the codes themselves.

4. Chapter 3. Simplified and Direct Methods

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   This chapter presents simplified and direct methods, which are easy to apply but overlook several important aspects. The simplified method, though now considered outdated, is based on universal mechanical principles that remain valid, such as the application of inertial forces on a structure. Direct methods, by contrast, derive directly from the time-history records of real earthquakes, providing a more accurate representation of seismic response.

5. Chapter 4. Artificial Accelerogram

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   In seismic regions where only limited data and records are available, generating artificial accelerograms can be a practical and effective solution for calculating seismic actions. Artificial accelerograms are designed to match the elastic response spectra required by codes, under restrictions consistent with the earthquake’s magnitude and other relevant features influencing ground acceleration. Their generation is based on stochastic processes explained in this chapter as well as the spectral functions and possible adjustments.

6. Chapter 5. Seismic Hazard Analyses

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   The seismic hazard analyses are considered the best methods to estimate seismic inputs, since they identify and combine, in both mathematical and physical ways, many uncertainties involved in a seismic event. They account for the seismic-geological context and historical earthquakes through seismogenic zones and attenuation equations. The analyses can be developed in probabilistic or deterministic ways, providing several scenarios. The former provides the most likely earthquake, whereas the latter provides the worst-case earthquake.

7. Chapter 6. Physically Based Seismic Hazard Analysis

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   The physically based seismic hazard analysis is probably the most advanced analysis, computationally, compared to the others described in this book. For this reason, although this method also accounts for seismic hazard analysis like those explained in Chap. 5, it is described separately. This method follows the same procedures as the seismic hazard analyses, with only one main difference: the attenuation equations are not used, and they are replaced by empirical Green’s functions to estimate the spatial soil displacement along the wave path.

8. Chapter 7. Case Studies

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   In this chapter, some practical examples of technical and research projects are described. The studied structures include a pile-supported wharf, a fire station building, embankment and concrete dams, and storage tanks. The main mechanical concepts and analyses of the structures under earthquakes have been explained for didactic purposes; however, the goal is to show what seismic input was applied and to discuss some issues related to seismic design. For all examples, the authors participated in the design; in this sense, they represent professional experiences.

9. Chapter 8. Appendices

   Enrico Zacchei, Reyolando M. L. R. F. Brasil

   Abstract

   For completeness, three appendices are provided to support the methodologies described in this book and to explain some more complex mathematical theories. In particular, they cover equations related to the Fourier spectrum, the elastic response spectrum with four branches, and the empirical Green’s function.

10. Backmatter