Three amplification mechanisms of large accelerations over 20 m/s2 are related to various non-liner behaviors and explained by using the non-stationary Fourier spectra. The frequencies of dominant components are compared with the natural frequencies with the ratios (1:3:5:7) of a shear-spring model of the underground soil. Thus, one of the amplification mechanisms is supposed to result from the...

After learning from several devastating earthquakes in China in recent years, stricter design criteria have been introduced in the current Chinese seismic design code. To investigate the reliability of the current seismic design code, seismic fragility analyses were performed for 45 10-story reinforced concrete (RC) frame-shear wall structures designed according to the current Chinese seismic d...

The stiffness and damping of pile foundations are proposed, which vary with the ratio of shear modulus Gi / Go to indicate the nonlinear properties of soil. The range of Gi / Go is defined with different vibration intensities for applications, and a computer program DYNAN is available based on the boundary zone model with non-reflective interface. Two engineering cases are studied to illustrate...

Using finite element nonlinear analysis, the dynamic soil pressure on perimeter retainingwalls of structures is investigated. Nonlinear Drucker Prager failure criterion is used to model the soilbehavior in the near field. The far field soil and the middle structure are assumed to behave as linearelastic materials. The soil-wall interface behavior is modeled incorporating nonlinear interfaceelem...

Free vibration of soil often occurs during earthquakes. Since the vibration caused by earthquake does not have (steady state harmonic vibration) continuity, the alluvium vibrates with its natural frequency between two natural seismic waves. This study evaluates the effect of piles on the period of free vibration of a soil layer using numerical method. In the first stage, using analytical equati...

Multi-channel Analysis of Surface Waves (MASW) is a seismic wave propagation method which involves the measurement of Rayleigh waves propagating along the surface of a medium. The method is non-intrusive, fast and practical and it has been successfully utilized for the in-situ evaluation of shear modulus and layer thicknesses of soils and, more recently, pavement systems. The method is also wid...

The New Madrid seismic zone is the most important regional seismic hazard in middle America, having produced several very large earthquakes in historic and geologic time. In this study we simulate time histories in Memphis, Tennessee, and St. Louis, Missouri, for M 7.5 and M 8.0 earthquakes along two faults in the New Madrid seismic zone. Simulations are based on a well-established and calibrat...

SHAKE2000 and DEEPSOIL are the two most important programs to calculate the response analysis of soil layer. In order to analyze the similarities and differences between them, and to guide the improvement of the method and program of seismic response analysis of soil layer, 25 KiK net seismic records from 9 stations were selected as the research objects in this paper, from the aspects of surfac...