Three-dimensional analysis of spatially varying ground motions around a uniform canyon in a homogeneous half-space

1991 ◽  
Vol 20 (10) ◽  
pp. 911-926 ◽  
Author(s):  
Liping Zhang ◽  
Anil K. Chopra
Keyword(s):  
Half Space ◽  
Dimensional Analysis ◽  
Ground Motions ◽  
Three Dimensional ◽  
Homogeneous Half Space ◽  
Spatially Varying Ground Motions ◽  
Spatially Varying

scholarly journals Experimental and three-dimensional finite element method studies on pounding responses of bridge structures subjected to spatially varying ground motions

2016 ◽  
Vol 20 (1) ◽  
pp. 105-124 ◽  
Author(s):  
Li-Xiang He ◽  
Bipin Shrestha ◽  
Hong Hao ◽  
Kai-Ming Bi ◽  
Wei-Xin Ren
Keyword(s):  
Finite Element ◽  
Ground Motions ◽  
Three Dimensional ◽  
Element Model ◽  
Bridge Structures ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Spatially Varying Ground Motions ◽  
Spatially Varying ◽  
Bridge Models

Pounding and unseating damages to bridge superstructures have been commonly observed in many previous major earthquakes. These damages can essentially attribute to the large closing or opening relative displacement between adjacent structures. This article carries out an experimental study on the pounding responses of adjacent bridge structures considering spatially varying ground motions using a shaking table array system. Two sets of large-scale (1:6) bridge models involving two bridge frames were constructed. The bridge models were subjected to the stochastically simulated ground motions in bi-direction based on the response spectra of Chinese Guideline for Seismic Design of Highway Bridge for three different site conditions, considering three coherency levels. Two types of boundary conditions, that is, the fixed foundation and rocking foundation, were applied to investigate the influence of the foundation type. In addition, a detailed three-dimensional finite element model was constructed to simulate an experimental case. The nonlinear material behavior including strain rate effects of concrete and steel reinforcement is included. The applicability and accuracy of the finite element model in simulating bridge pounding responses subjected to spatially varying ground motions are discussed. The experimental and numerical results demonstrate that non-uniform excitations and foundation rocking can affect the relative displacements and pounding responses significantly.

Computation of Green’s tensor integrals for three‐dimensional electromagnetic problems using fast Hankel transforms

Geophysics ◽  
1984 ◽  
Vol 49 (10) ◽  
pp. 1754-1759 ◽  
Author(s):  
Walter L. Anderson
Keyword(s):  
Half Space ◽  
Three Dimensional ◽  
Hankel Transform ◽  
Electromagnetic Modeling ◽  
Electromagnetic Problems ◽  
Hankel Transforms ◽  
Homogeneous Half Space ◽  
Green's Tensor ◽  
Green’S Tensor ◽  
The Many

A new method is presented that rapidly evaluates the many Green’s tensor integrals encountered in three‐dimensional electromagnetic modeling using an integral equation. Application of a fast Hankel transform (FHT) algorithm (Anderson, 1982) is the basis for the new solution, where efficient and accurate computation of Hankel transforms are obtained by related and lagged convolutions (linear digital filtering). The FHT algorithm is briefly reviewed and compared to earlier convolution algorithms written by the author. The homogeneous and layered half‐space cases for the Green’s tensor integrals are presented in a form so that the FHT can be easily applied in practice. Computer timing runs comparing the FHT to conventional direct convolution methods are discussed, where the FHT’s performance was about 6 times faster for a homogeneous half‐space, and about 108 times faster for a five‐layer half‐space. Subsequent interpolation after the FHT is called is required to compute specific values of the tensor integrals at selected transform arguments; however, due to the relatively small lagged convolution interval used (same as the digital filter’s), a simple and fast interpolation is sufficient (e.g., by cubic splines).

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