1st Edition
Spatial Variation of Seismic Ground Motions Modeling and Engineering Applications
The spatial variation of seismic ground motions denotes the differences in the seismic time histories at various locations on the ground surface. This text focuses on the spatial variability of the motions that is caused by the propagation of the waveforms from the earthquake source through the earth strata to the ground surface, and it brings together the various aspects underlying this complicated phenomenon.
Topics covered include:
- Evaluation of the spatial variability from seismic data recorded at dense instrument arrays by means of signal processing techniques
- Presentation of the most widely used parametric coherency models, along with brief descriptions of their derivation
- Illustration of the causes underlying the spatial variation of the motions and its physical interpretation
- Estimation of seismic ground-surface strains from single station data, spatial array records, and analytical methods
- Introduction of the concept of random vibrations as applied to discrete-parameter and continuous structural systems on multiple supports
- Generation of simulations and conditional simulations of spatially variable seismic ground motions
- Overview of the effects of the spatial variability of seismic motions on the response of long structures, such as pipelines, bridges and dams, with brief descriptions of select seismic codes that incorporate spatial variability issues in their design recommendations
This book may serve as a tutorial and/or reference for graduate students, researchers and practicing engineers interested in advancing the current state of knowledge in the analysis and modeling of the spatial variation of the seismic ground motions, or utilizing spatially variable excitations in the seismic response evaluation of long structures.
Introduction
Stochastic estimation of spatial variability
Basic definitions
Stochastic processes
Bi-variate stochastic processes
Coherency
Multi-variate stochastic processes and stochastic fields
Parametric modeling of spatial variability
Parametric power spectral densities
Early studies on spatial variability
Dependence of coherency on physical parameters
Parametric coherencymodeling
Parametric cross spectrum modeling
Physical characterization of spatial variability
Frequency-wavenumber (F-K) spectra
Amplitude and phase variability
Seismic ground-surface strains
Semi-empirical estimation of the propagation velocity
Estimation of the surface strain field
Accuracy of single-station strain estimation
Incoherence vs propagation effects in surface strains
Displacement gradient estimation from array data
Considerations in the estimation of seismic ground strains
Random vibrations for multi-support excitations
Introduction to random vibrations
Discrete-parameter systems
Distributed-parameter systems
Analysis of rms lifeline response
Additional random vibration considerations
Simulations of spatially variable ground motions
Simulation of random processes
Simulation of random fields
Simulation ofmulti-variate stochastic vector processes
Conditionally simulated ground motions
Conditional simulation of random processes
Processing of simulated acceleration time series
Example applications
Engineering Applications
Large, mat, rigid foundations
Dams
Suspension and cable-stayed bridges
Highway bridges
Some concluding remarks
References
Biography
Aspasia Zerva