scholarly journals Hamiltonian Formulation of the Free Surface and Interface Motions in a Tank (2nd Report, Nonlinear Time History Response Analysis)

2007 ◽  
Vol 73 (735) ◽  
pp. 2891-2899
Author(s):  
Kensuke HARA ◽  
Hiroki TAKAHARA
Keyword(s):  
Free Surface ◽  
Hamiltonian Formulation ◽  
Time History ◽  
Response Analysis ◽  
Surface And Interface ◽  
Time History Response ◽  
Nonlinear Time History

A statistical study on artificially generated earthquake records

1976 ◽  
Vol 3 (1) ◽  
pp. 11-19
Author(s):  
W. K. Tso ◽  
B. P. Guru
Keyword(s):  
Statistical Study ◽  
Spectral Response ◽  
Flexible Structures ◽  
Time History ◽  
Maximum Response ◽  
Response Analysis ◽  
Seismic Region ◽  
Natural Period ◽  
Earthquake Records ◽  
Time History Response

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.

Settlement Analysis of Soft Ground Replacement under Earthquake

2012 ◽  
Vol 166-169 ◽  
pp. 2379-2382 ◽  
Author(s):  
Zhong Liu ◽  
Shu Hong An ◽  
Rong Hong Yuan ◽  
Fei Li
Keyword(s):  
Time History ◽  
Vertical Displacement ◽  
Response Analysis ◽  
Soft Ground ◽  
Positive Contribution ◽  
Foundation Soil ◽  
Time History Response ◽  
Dynamic Time ◽  
Settlement Analysis ◽  
Different Thickness

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.

THE BRIDGES WITH UNSEATING PREVENTION DEVICES ANALYZED THROUGH NONLINEAR TIME HISTORY ANALYSIS AND HILBERT–HUANG TRANSFORM

2010 ◽  
Vol 02 (01) ◽  
pp. 115-134
Author(s):  
YEOU-FONG LI ◽  
TSENG-HSING HSU ◽  
K. H. LEN
Keyword(s):  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Hilbert Huang Transform ◽  
Time Frequency ◽  
Rubber Bearing ◽  
History Analysis ◽  
Time History Response ◽  
Nonlinear Time History ◽  
Seismic Forces

In this paper, the mechanical behaviors of bridges with unseating prevention devices in the superstructure were investigated. These devices can prevent bridge from unseating and divert most of the seismic forces from transferring to the bridge columns. The models of the rubber bearing, restrainer, and shear key were proposed and implemented into the SAP 2000 to obtain the seismic response of the bridge. The nonlinear time history analysis was used to determine the time history response of the superstructure of the bridge. In the meantime, the Hilbert–Huang Transform (HHT) was used to transfer the displacement–time responses of the superstructure of the bridge into the time–frequency domain, while the spectra are a function of both frequency and time. The spectra of the HHT can be used to determine the operation sequences of the unseating prevention devices.

scholarly journals Seismic Assessment Of Multi-Span Steel Railway Bridge In Turkey Base On The Nonlinear Time History Analyses

2017 ◽  
Author(s):  
Mehmet F. Yilmaz ◽  
Barlas Ö. Çağlayan
Keyword(s):  
Fragility Curves ◽  
Time History ◽  
Field Measurements ◽  
Response Analysis ◽  
Northridge Earthquake ◽  
Railway Bridge ◽  
Railway Line ◽  
Damage Data ◽  
Steel Railway Bridge ◽  
Nonlinear Time History

Abstract. It has been seen that bridges are vulnerable to earthquakes by the research studies after important earthquakes like the San Fernando earthquake (1971 USA), the Northridge earthquake (1994 USA), Great Hanshin earthquake (1995 Japan), and Chi-Chi earthquake (1999 Taiwan). These studies show that to do the seismic risk assessments for bridges, fragility curves are useful tools. There are the most used two ways to generate the fragility curves; empirically or analytically. If the damage reports from past earthquakes are available then empirical fragility curves may be developed but otherwise seismic response analysis of structures may be used to develop analytical fragility curves. In Turkey, earthquake damage data are very limited so to develop the fragility curves for the Alasehir bridge, the analytical method is used in this study. The bridge that is studied on is lying on the Manisa-Afyon railway line that is very important for both transportation and freightage. As the most of the country land covers the seismically active zones it is a necessity to find out the vulnerability of the Alasehir bridge. The Alasehir bridge is consists of six 30 m length truss system span with a total span length of 189.43 m supported by 2 abutments and 5 truss piers with height of 12.5 m, 19 m, 26 m, 33 m and 40 m. Sap2000 is used for computer model of the Alaşehir bridge and the model is refined by using field measurements. Then selected 60 different real earthquake data are used for the analysis by using the refined model. Both material nonlinearity and Δ-δ are considered during the analysis. With this study, seismic behavior of Alasehir steel railway bridge is determined. Truss piers reaction and displacements are used to determine the seismic performance of the Alasehir bridge. Different IMs are compared in terms of efficiency, practicality, and sufficiency. Component and system fragility curve are derived for most proper IMs.

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