Critical Excitation Methods in Earthquake Engineering

Critical Excitation Methods in Earthquake Engineering

by Izuru Takewaki
     
 

During the last three decades critical excitation problems in earthquake engineering have been studied extensively, and have formed a new research discipline in applied mechanics and structural engineering. These investigations have been motivated by the fact that uncertainties in the occurrence of earthquakes, the fault rupture mechanism, the wave propagation

See more details below

Overview

During the last three decades critical excitation problems in earthquake engineering have been studied extensively, and have formed a new research discipline in applied mechanics and structural engineering. These investigations have been motivated by the fact that uncertainties in the occurrence of earthquakes, the fault rupture mechanism, the wave propagation mechanism, the ground properties, etc. cause much difficulty in defining reasonable design ground motions especially for important buildings.
In the past, once a big earthquake occurred, some building codes were upgraded. However, it is true that this repetition never resolves all the issues and new damage problems occur even recently. In order to overcome this problem, a new paradigm has to be posed. To the author’s knowledge, the concept of ‘critical excitation’ and the structural design based upon this concept can become one of such new paradigms.
In the seismic resistant design of building structures, the concept of ‘performance-based design’ has become a new paradigm guaranteeing the maximum satisfaction of building owners. The quality and reliability of the performance-based design certainly depend on the scientific rationality of design ground motions.
The most critical issue in the seismic resistant design is the resonance. The promising approaches are to shift the natural period of a building through seismic control and to add damping in the building. However it is also true that the seismic control is under development and more sufficient time is necessary to respond to uncertain ground motions. This book introduces a new probabilistic and energy-based critical excitation approach to overcome several problems in the scientific and rational modeling of ground motions. The author hopes that this book will help the development of new seismic-resistant design methods of buildings for such unpredicted or unpredictable ground motions.

Read More

Product Details

ISBN-13:
9780080453095
Publisher:
Elsevier Science
Publication date:
02/15/2007
Pages:
296
Product dimensions:
0.69(w) x 6.14(h) x 9.21(d)

Meet the Author

Table of Contents


Preface     x
Permission Details     xiv
Overview of Seismic Critical Excitation Method
What is critical excitation?     1
Origin of critical excitation method (Drenick's approach)     3
Shinozuka's approach     7
Historical sketch in early stage     8
Various measures of criticality     9
Subcritical excitation     10
Stochastic excitation     11
Convex models     12
Nonlinear or elastic-plastic SDOF system     13
Elastic-plastic MDOF system     14
Critical envelope function     15
Robust structural design     15
Critical excitation method in earthquake-resistant design     17
Critical Excitation for Stationary and Non-stationary Random Inputs
Introduction     23
Stationary input to single-degree-of-freedom model     24
Stationary input to multi-degree-of-freedom model     26
Conservativeness of bounds     29
Non-stationary input to SDOF model     31
Non-stationary input to MDOF model     34
Numerical examples for SDOF model     36
Numerical examples for MDOF model     38
Conclusions     40
Critical Excitation forNon-proportionally Damped Structural Systems
Introduction     43
Modeling of input motions     43
Response of non-proportionally damped model to non-stationary random excitation     44
Critical excitation problem     49
Solution procedure     50
Critical excitation for acceleration (proportional damping)     51
Numerical examples (proportional damping)     53
Numerical examples (non-proportional damping)     54
Numerical examples (various types of damping concentration)     55
Conclusions     58
Critical Excitation for Acceleration Response
Introduction     63
Modeling of input motions     64
Acceleration response of non-proportionally damped model to non-stationary random input     64
Critical excitation problem     69
Solution procedure     70
Numerical examples     72
Model with non-proportional damping-1     73
Model with non-proportional damping-2     73
Model with proportional damping     78
Conclusions     80
Critical Excitation for Elastic-Plastic Response
Introduction     81
Statistical equivalent linearization for SDOF model     82
Critical excitation problem for SDOF model     84
Solution procedure     86
Relation of critical response with inelastic response to recorded ground motions     86
Accuracy of the proposed method     91
Criticality of the rectangular PSD function and applicability in wider parameter ranges     93
Critical excitation for MDOF elastic-plastic structures     95
Statistical equivalent linearization for MDOF model     95
Critical excitation problem for MDOF model     100
Solution procedure     101
Relation of critical response with inelastic response to recorded ground motions     102
Accuracy of the proposed method     105
Conclusions     107
Critical Envelope Function for Non-stationary Random Earthquake Input
Introduction     112
Non-stationary random earthquake ground motion model     113
Mean-square drift     114
Problem for finding critical envelope function     115
Double maximization procedure     115
Discretization of envelope function     116
Upper bound of mean-square drift     117
Numerical examples     118
Critical excitation for variable envelope functions and variable frequency contents     123
Conclusions      123
Robust Stiffness Design for Structure-Dependent Critical Excitation
Introduction     130
Problem for fixed design     130
Problem for structure-dependent critical excitation     132
Solution procedure     133
Numerical design examples     136
Response to a broader class of excitations     137
Response to code-specified design earthquakes     141
Conclusions     142
Critical Excitation for Earthquake Energy Input in SDOF System
Introduction     146
Earthquake input energy to SDOF system in frequency domain     148
Property of energy transfer function and constancy of earthquake input energy     149
Critical excitation problem for earthquake input energy with acceleration constraint     151
Critical excitation problem for earthquake input energy with velocity constraint     153
Actual earthquake input energy and its bound for recorded ground motions     154
Conclusions     161
Critical Excitation for Earthquake Energy Input in MDOF System
Introduction     165
Earthquake input energy to proportionally damped multi-degree-of-freedom system (frequency-domain modal analysis)     165
Earthquake input energy to non-proportionally damped MDOF system (frequency-domain modal analysis)      168
Earthquake input energy without modal decomposition     171
Examples     172
Critical excitation for earthquake energy input in MDOF system     179
Conclusions     179
Critical Excitation for Earthquake Energy Input in Soil-Structure Interaction System
Introduction     181
Earthquake input energy to fixed-base SDOF system     183
Earthquake input energy to SSI systems     184
Actual earthquake input energy to fixed-base model and SSI system     192
Critical excitation for earthquake energy input in SSI system     198
Critical excitation problem     202
Upper bound of Fourier amplitude spectrum of input     204
Solution procedure and upper bound of input energy     205
Critical excitation problem for velocity constraints     206
Solution procedure for velocity constraint problems     207
Numerical examples 1 (one-story model)     208
Numerical examples 2 (three-story model)     211
Conclusions     214
Critical Excitation for Earthquake Energy Input in Structure-Pile-Soil System
Introduction     221
Transfer function to bedrock acceleration input     222
Earthquake input energy to structure-pile system     224
Earthquake input energy to structure     226
Input energies by damage-limit level earthquake and safety-limit level earthquake     227
Critical excitation for earthquake energy input in structure-pile-soil system     236
Conclusions     237
Critical Excitation for Earthquake Energy Input Rate
Introduction     244
Non-stationary ground motion model     244
Probabilistic earthquake energy input rate: a frequency-domain approach     245
Critical excitation problem for earthquake energy input rate     250
Solution procedure for double maximization problem     252
Mean energy input rate for special envelope function     254
Critical excitation problem for non-uniformly modulated ground motion model     256
General problem for variable envelope function and variable frequency content     257
Numerical examples     258
Conclusions     264
Index     267

Read More

Customer Reviews

Average Review:

Write a Review

and post it to your social network

     

Most Helpful Customer Reviews

See all customer reviews >