Strong earthquake motion and site conditions: Hollywood

1970 ◽  
Vol 60 (4) ◽  
pp. 1271-1289 ◽  
Author(s):  
C. M. Duke ◽  
J. E. Luco ◽  
A. R. Carriveau ◽  
P. J. Hradilek ◽  
R. Lastrico ◽  
...  

abstract An investigation was made to determine the feasibility of isolating the effects of site conditions on strong earthquake accelerograms. The set of accelerograms recorded simultaneously in 1952 at the roof, in the basement and on the ground outside the 14-story Hollywood Storage Building was chosen for analysis. Fourier spectra were computed for the two horizontal components at each of the three recording places and were used after smoothing to compute the ratios of spectra for adjacent points. Dynamic models of the subsurface conditions, the foundation and the building were established. Certain of the spectral ratios were also determined theoretically. The primary result is the development of a method of isolating effects of site conditions in Fourier spectra of accelerograms. Good theoretical checks were obtained on soil-structure interaction and structural response in the east-west direction. The absence of bedrock accelerograms prevented the obtaining of a theoretical check on free-field amplification, although plausible bedrock Fourier spectra were obtained. The subsurface model should be useful for further analyses.

1982 ◽  
Vol 72 (2) ◽  
pp. 615-636
Author(s):  
Robert F. Nau ◽  
Robert M. Oliver ◽  
Karl S. Pister

Abstract This paper describes models used to simulate earthquake accelerograms and analyses of these artificial accelerogram records for use in structural response studies. The artificial accelerogram records are generated by a class of linear linear difference equations which have been previously identified as suitable for describing ground motions. The major contributions of the paper are the use of Kalman filters for estimating time-varying model parameters, and the development of an effective nonparametric method for estimating the variance envelopes of the accelerogram records.


Author(s):  
S. J. Dyke ◽  
B. F. Spencer ◽  
M. K. Sain ◽  
J. D. Carlson

Abstract In this paper, the efficacy of magnetorheological (MR) dampers for seismic protection of structures is investigated through a series of experiments in which an MR damper is used to control a three story test structure subjected to a one-dimensional earthquake motion. Because of the intrinsic nonlinearity of the MR damper, several earthquake amplitudes are considered to investigate the performance, in terms of both peak and rms responses, of this control systems over a range of loading conditions. The results indicate that the MR damper is quite effective for structural response reduction over a wide class of seismic excitations.


2002 ◽  
Author(s):  
S Day ◽  
M Doroudian ◽  
A Elgamal ◽  
S Gonzales ◽  
F Heuze ◽  
...  

2021 ◽  
pp. 1-36
Author(s):  
Avnish Mahendra Pandey ◽  
K. V. Nagendra Gopal

Abstract This paper presents the vibroacoustic response of pure functionally graded plates under transient loading of mechanical nature. The functionally graded plate is modelled using the conventional first-order shear deformation theory to incorporate the effects of transverse shear and rotary inertia. The mid-surface variables are determined using the finite element method. Transient structural response is determined using Newmark Beta time marching scheme and the acoustic pressure in the free field is obtained using the time-domain Rayleigh integral. The effective material properties of the FG plate and the transient response of both the structural and acoustic fields have been computed in MATLAB. The influence of the volume fraction index, thickness ratio and boundary conditions of pure FG plate on its transient vibroacoustic response is investigated by a detailed parametric study.


2019 ◽  
Vol 9 (4) ◽  
pp. 771
Author(s):  
Peng Su ◽  
Yanjiang Chen ◽  
Zhongwei Zhao ◽  
Weiming Yan

A curved bridge test model with a scale ratio of 1:10 was constructed to investigate the influence of site conditions on curved bridges with longitudinal slopes based on a similar theory. The natural ground motions of five different groups, namely, Sites A–E, were selected from the Pacific Earthquake Engineering Center (PEER) seismic database, and the shaking table model test was conducted under horizontal unidirectional and bidirectional excitations. Results showed that the structural response of the curved bridge is sensitive to the ground motion of different site conditions. Spatial characteristics are observed in the main girder structural response of the curved bridge. When the curved bridge is parallel to the direction of the principal ground motion, the rotation effect of the main girder is greater than that perpendicular to the direction of the principal ground motion. The rotation effect of the main girder leads to evident beam end and bearing displacements at the low pier. The seismic excitation direction and pier height notably affect the displacement response of the pier, and the tangential displacement response of the fixed pier is sensitive to seismic excitation.


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