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Showing 3 results for Dynamic Displacement

H. Alielahi, M. Kamalian, J. Asgari Marnani, M. K. Jafari, M. Panji,
Volume 11, Issue 1 (5-2013)
Abstract

In this paper, an advanced formulation of a time-domain two-dimensional boundary element method (BEM) is presented and

applied to calculate the response of a buried, unlined, and infinitely long cylindrical cavity with a circular cross-section subjected

to SV and P waves. The applicability and efficiency of the algorithm are verified with frequency-domain BEM examples of the

effect of cylindrical cavities on the site response analysis. The analysis results show that acceptable agreements exist between

results of this research and presented examples. For a shallow cavity, the numerical results demonstrate that vertically incident

SV wave reduces the horizontal components of the motion on the ground surface above the cavity, while it significantly increases

the vertical component for a dimensionless frequency (&eta) of 0.5 and h/a=1.5. The maximum values of normalized displacements

in vertical component of P waves are larger than horizontal component of SV waves for &eta=1.0. For a deeply embedded cavity,

the effect of the cavity on the surface ground motion is negligible for incident SV wave, but it increases the vertical component of

the displacement for incident P wave. Additionally, far and near distances from the center of the cavity show different amplitude

patterns of response due to the cavity effect. Increasing the distance from the center of the cavity, the amplitude of displacement

and the effect of the cavity attenuates significantly.


M. Afzalirad, M. Kamalian, M. K. Jafari, A. Sohrabi-Bidar,
Volume 12, Issue 1 (1-2014)
Abstract

In this paper, an advanced formulation of time-domain, two-dimensional Boundary Element Method (BEM) with material damping is presented. Full space two-dimensional visco-elastodynamic time-convoluted kernels are proposed in order to incorporate proportional damping. This approach is applied to carry out site response analysis of viscoelastic topographic structures subjected to SV and P incident waves. Seismic responses of horizontally layered site, semi-circular canyons, slope topography and ridge sections subjected to these incident waves are analyzed in order to demonstrate the accuracy of the kernels and the applicability of the presented viscoelastic boundary element algorithm. The results show an excellent agreement with recent published results obtained in frequency domain. Also, the effects of different material damping ratios on site response are investigated.
M.a. Rahgozar,
Volume 13, Issue 3 (12-2015)
Abstract

The interactive effects of adjacent buildings on their seismic performance are not frequently considered in seismic design. The adjacent buildings, however, are interrelated through the soil during seismic ground motions. The seismic energy is redistributed in the neighboring buildings through multiple structure-soil-structure interactions (SSSI). For example, in an area congested with many nearby tall and/or heavy buildings, accounting for the proximity effects of the adjacent buildings is very important. To solve the problem of SSSI successfully, researchers indicate two main research areas where need the most attention: 1) accounting for soil nonlinearity in an efficient way, and 2) spatial analysis of full 3D soil-structure models. In the present study, three-dimensional finite element models of tall buildings on different flexible foundation soils are used to evaluate the extent of cross interaction of adjacent buildings. Soil nonlinearity under cyclic loading is accounted for by Equivalent Linear Method (ELM) as to conduct large parametric studies in the field of seismic soil-structure interaction, the application of ELM is preferred over other alternatives (such as application of complicated constitutive soil models) due to the efficiency and reliability of its results. 15 and 30 story steel structures with pile foundations on two sandy and clayey sites are designed according to modern codes and then subjected to several actual earthquake records scaled to represent the seismicity of the building sites. Results show the cross interaction of adjacent buildings on flexible soils, depending on their proximity, increases dynamic displacements of buildings and reduces their base shears. 



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