A statistical study on artificially generated earthquake records

1976 ◽  
Vol 3 (1) ◽  
pp. 11-19
Author(s):  
W. K. Tso ◽  
B. P. Guru

A statistical study has been done to investigate (i) the variation of spectral responses of structures due to artificially generated earthquake records with identical statistical properties, (ii) the effect of duration of strong shaking phase of artificial earthquakes on the response of structures, and (iii) the number of earthquake records needed for time-history response analysis of a structure in a seismic region. The results indicate that the flexible structures are more sensitive to the inherent statistical variations among statistically identical earthquake records. Consequently several records must be used for time-history response analysis. A sample of eight or more records appear to provide a good estimate of mean maximum response. The duration of strong shaking can significantly affect the maximum response. Based on the results, it is suggested that for the purpose of estimating peak response, the strong shaking duration of the input earthquake motion should be at least four times the natural period of the structure. The maximum responses due to statistically identical ground motion records are observed to fit approximately the type 1 extreme value distribution. Thus, it is rationally possible to choose a design value based on the mean, standard deviation of the spectral response values and tolerable probability of exceedance.

2012 ◽  
Vol 166-169 ◽  
pp. 2379-2382 ◽  
Author(s):  
Zhong Liu ◽  
Shu Hong An ◽  
Rong Hong Yuan ◽  
Fei Li

The dynamic time-history response analysis method was employed to analyze the dynamic response of soft ground replacement with sand-gravel cushion. The deformation distribution of soft ground replacement with different thickness sand-gravel cushion was investigated under seismic wave. The results reveal that the bearing and asti-deformation capacity can be improved effectively for replacement sand-gravel cushion under earthquake loads by increasing the thick of cushion. The vertical displacement of foundation soil decreases gradually with the increase of the thick of cushion. The practice shows that replacement sand-gravel cushion provides a positive contribution to the aseismic effect of foundation soils mass. The present research can provide some references to similar projects.


1989 ◽  
Vol 1989 (38) ◽  
pp. 3-14
Author(s):  
Hiroshi AKIYAMA ◽  
Masanao NAKAYAMA

2012 ◽  
Vol 204-208 ◽  
pp. 2501-2504
Author(s):  
Xian Li Yan ◽  
Qing Ning Li ◽  
Fan Yang ◽  
Chang Gao ◽  
Lei Wei

Two curved bridges with typical line shapes: C shaped curved bridge and S shaped curved bridge were selected to study the influence of line shapes on the dynamic parameters of the curved bridge. Spatial finite element analysis models were established and the seismic responses of the two bridges in different earthquake input directions were studied by the elastic dynamic time history method. Results show that: except for the first natural period, the rest natural periods of the two bridges are basically the same; the earthquake resistant capability of the C shaped curved bridge is worse than that of the S shaped curved bridge; under earthquake, the control input direction is Y-direction, and the control internal force is the axial force-Fx, shear Fy, and the moment Mz; relative to the horizontal seismic inputs, the internal force produced by the vertical seismic input is very small, and it can be resisted by structural measures in seismic design.


2011 ◽  
Vol 255-260 ◽  
pp. 1096-1101
Author(s):  
Qing Zhao

Taking an engineering design case about a city elevated curved box girders bridge, the dynamic calculating model of the curved box girders bridge is created by the finite element analysis program ANSYS. The analysis of curved box girders bridge with space seismic response are discussed, and a time history analysis is conducted for the curved box girders bridge subjected to the E1 Centro earthquake waves in two conditions.The internal force and the displacement time history response curve of the curved box girders bridge are obtained. The results indicate that the seismic response of curved box girders bridge with three-dimensional earthquake are bigger than two-dimensional, and consider the vertical seismic have considerable influence on the axial force of bridge piers, the internal force and displacement of box girders.


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