Inelastic Response of a Spectrum-Compatible Artificial Accelerogram

1989 ◽  
Vol 5 (3) ◽  
pp. 477-493 ◽  
Author(s):  
Michael E. Barenberg
Keyword(s):  
Response Spectrum ◽  
Ground Motions ◽  
Normalization Procedure ◽  
Target Response ◽  
Single Degree Of Freedom ◽  
Inelastic Response ◽  
Strong Ground Motions ◽  
Single Degree ◽  
Initial Frequency ◽  
Strong Ground

The validity of evaluating the inelastic response of a structure subjected to an artificial accelerogram in lieu of a suite of eight recorded ground motions is determined by analyzing the inelastic response of single-degree-of-freedom oscillators over a range of frequencies from 1.0 to 10.0 Hz. A normalization procedure to minimize the dispersion in the ductility response of the oscillators subjected to the recorded ground motions is investigated. The artificial accelerogram is derived by superimposing closely spaced sine waves in order to match a target response spectrum. The results show that the artificial accelerogram is expected to produce the same amount of damage as the average of the recorded strong ground motions for structures with an initial frequency of less than 5.0 Hz and close to the average for the entire suite of ground motions for structures with frequencies greater then 5.0 Hz.

Spectral Variability and Its Relationship to Structural Response Estimated from Scaled and Spectrum-Matched Ground Motions

2016 ◽  
Vol 32 (4) ◽  
pp. 2191-2205 ◽  
Author(s):  
A. E. Seifried ◽  
J. W. Baker
Keyword(s):  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Degree Of Freedom ◽  
Structural Systems ◽  
Spectral Variability ◽  
Single Degree Of Freedom ◽  
Inelastic Response ◽  
Single Degree ◽  
Spectral Dispersion

Conditional spectral dispersion ( CSD) is a measure of response spectrum variability that implicitly characterizes the variety of spectral shapes within a suite of ground motions. It is used here to explain the discrepancy between median structural demands estimated from different suites of scaled and spectrum-matched ground motions. Performing response history analyses with spectrum-matched ground motions is known to result in unconservatively biased median demand estimates in some cases. Herein, several suites of scaled ground motions with equivalent median intensities and varying levels of CSD are selected. A single suite of spectrum-matched ground motions is also created. These records are used to analyze the responses of inelastic single-degree-of-freedom and first-mode-dominated multiple-degree-of-freedom structural systems. Collapse capacities are also examined. A consistent trend between CSD and resulting median responses indicates that the bias phenomenon can be fully explained by an asymmetric relationship between conditional spectral ordinates at periods affecting inelastic response.

Generation of seismic excitations compatible with target spectrum: application to Eurocode 8

2020 ◽  
Vol 18 (1) ◽  
pp. 122-135
Author(s):  
Abdellah Boudina ◽  
Malek Hammoutene
Keyword(s):  
Epicentral Distance ◽  
Response Spectrum ◽  
Ground Motions ◽  
Environmental Parameters ◽  
Eurocode 8 ◽  
Ground Acceleration ◽  
Content Type ◽  
Strong Ground Motions ◽  
Acceleration Time Histories ◽  
Strong Ground

Purpose This paper aims to artificially generate seismic accelerograms compatible with the response spectrum imposed as a function of the given environmental parameters such as magnitude, epicentral distance and type of soil. This study is necessary for the non-linear dynamic analysis of structures in regions where real seismic records are not available. Design/methodology/approach First, a stochastic iterative method is used to estimate the spectral densities of acceleration power from the respective target response spectra. Thereafter, based on the superposition of seismic waves, a subsequent iterative procedure, which implicitly takes into account the non-stationary character of temporal intensity content of strong ground motions, is developed to synthesize, from these power spectral density, the corresponding acceleration time histories. The phase contents of the ground acceleration samples, thus obtained, are generated using a probability density function of phase derivatives with characteristic parameters estimated from seismological considerations. When based on seismic codes spectrum compatible criteria, this procedure can be used to generate strong ground motions for structural design. Findings The results found show that the forms of acceleration of the target and the simulated signals have similar characteristics in terms of strong motion durations, the peak ground acceleration values, corresponding time of occurrence and also, the corresponding cumulative energy functions follow practically the same pattern of variations. Originality/value The aim of this study is to generate seismic accelerograms compatible with regulatory spectra by the composition of the three acceleration duration segments based on environmental parameters (magnitude, epicentral distance and type of soil) and which subsequently serves to control the time envelope of the generated signals, and therefore the random generation of phase derivatives, which has not been previously treated.

An analysis of seismoscope data from the Parkfield earthquake of June 27, 1966

1967 ◽  
Vol 57 (6) ◽  
pp. 1143-1159 ◽  
Author(s):  
D. E. Hudson ◽  
W. K. Cloud
Keyword(s):  
Response Spectrum ◽  
Ground Motions ◽  
Field Conditions ◽  
Geologic Structure ◽  
Acceleration Time ◽  
Strong Ground Motions ◽  
Parkfield Earthquake ◽  
Strong Ground

Abstract An analysis of 16 seismoscope records from the Parkfield earthquake indicates the general usefulness of seismoscope data as a supplement to information produced by recording accelerographs. The pattern of attenuation of response spectrum values with distance from the fault was obtained, and certain anomalies in response spectrum values which may be related to local geologic structure were noted. The initial strong ground motions in the immediate vicinity of the fault were found to be predominately transverse to the fault. A direct comparison of seismoscope results with response spectrum curves calculated from recorded groud acceleration-time curves indicates an overall seismoscope accuracy under typical field conditions of 10-15 per cent.

scholarly journals Broadband Strong-Motion Prediction for Future Nankai-Trough Earthquakes Using Statistical Green’s Function Method and Subsequent Building Damage Evaluation

2021 ◽  
Vol 11 (15) ◽  
pp. 7041
Author(s):  
Baoyintu Baoyintu ◽  
Naren Mandula ◽  
Hiroshi Kawase
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Nankai Trough ◽  
Ground Motions ◽  
Building Damage ◽  
Steel Buildings ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Strong Ground Motions ◽  
Strong Ground

We used the Green’s function summation method together with the randomly perturbed asperity sources to sum up broadband statistical Green’s functions of a moderate-size source and predict strong ground motions due to the expected M8.1 to 8.7 Nankai-Trough earthquakes along the southern coast of western Japan. We successfully simulated seismic intensity distributions similar to the past earthquakes and strong ground motions similar to the empirical attenuation relations of peak ground acceleration and velocity. Using these results, we predicted building damage by non-linear response analyses and find that at the regions close to the source, as well as regions with relatively thick, soft sediments such as the shoreline and alluvium valleys along the rivers, there is a possibility of severe damage regardless of the types of buildings. Moreover, the predicted damage ratios for buildings built before 1981 are much higher than those built after because of the significant code modifications in 1981. We also find that the damage ratio is highest for steel buildings, followed by wooden houses, and then reinforced concrete buildings.

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