scholarly journals Comparison of Base Shears Estimated from Floor Accelerations and Column Shears

2011 ◽  
Vol 27 (3) ◽  
pp. 939-946 ◽  
Author(s):  
Rakesh K. Goel

This paper compares base shears computed from floor accelerations (inertial base shear) and column shears (structural base shear) for two mid-rise, multistory buildings due to a suite of 30 earthquake ground motions. The presented results demonstrate that the inertial base shear exceeds the structural base shear in the median by 10% to 20% and may exceed the structural base shear by as much as 70% for individual ground motions. Therefore, it is concluded that the inertial base shear computed from strong motion records should be used with caution to estimate the structural base shear.

2019 ◽  
Vol 9 (4) ◽  
pp. 4355-4360 ◽  
Author(s):  
Y. Fukushima ◽  
T. Nagao

In this paper, an evaluation of the variation of earthquake ground motions with a focus on site amplification factors based on spectral analysis is presented. By using strong motion record obtained at six sites in Japan, probability distributions of site amplification factors were shown. The relations between standard deviations of site amplification factors and distances between the sites were studied. The variations of representative values of earthquake ground motions based on the variations of site amplification factors were discussed by using probabilistic seismic hazard analysis with focus on Fourier amplitude and group delay time. The distributions of peak ground accelerations and peak ground velocities were shown. It is suggested that design earthquake ground motions considering the average site amplification factors may lead the engineering design on the dangerous side.


2010 ◽  
Vol 26 (2) ◽  
pp. 499-524 ◽  
Author(s):  
Adrian Rodriguez-Marek ◽  
James A. Bay ◽  
Kwangsoo Park ◽  
Gonzalo A. Montalva ◽  
Adel Cortez-Flores ◽  
...  

The Mw 8.4 23 June 2001 Southern Peru earthquake generated intense ground motions in a large region encompassing southern Peru and northern Chile. The earthquake was recorded by seven strong motion stations with peak ground accelerations ranging from 0.04 g to 0.34 g for site-to-fault distances ranging from about 70 km to 220 km. At this time, there are no other strong motion records for an earthquake of this magnitude. Hence, the strong motion data set from this earthquake is unique and of particular interest to engineers dealing with seismic design in subduction regions. This paper presents an engineering analysis of the strong motion records. Shear-wave velocity profiles were measured using Spectral Analysis of Surface Waves methods at four stations. Measured shear-wave velocities are high, indicating that all sites classify as stiff soil sites (Site C) according to the International Building Code classification scheme. The strong motion set is characterized by strong high frequency content at large distances from the fault. Site response contributed at least in part to the observed high frequency content in the ground motions. In general, current attenuation relationships for spectral acceleration underpredicted the observed ground motions.


1954 ◽  
Vol 44 (4) ◽  
pp. 551-569
Author(s):  
R. G. Merritt ◽  
G. W. Housner

Abstract This paper shows the quantitative effect that foundation compliance has on the maximum base shear force and the fundamental period of vibration in typical tall buildings subjected to strong-motion earthquakes. A study was made of five-, ten-, and fifteen-story building models on the Electric Analog Computer, subjecting them to the ground accelerations of actual earthquakes. The base shear forces were measured, the foundation compliance of the models being changed through a very wide range. The properties specified for the building models are shown to be similar to the properties found in real buildings. The experimental results imply that the maximum base shear forces in typical buildings of five stories and higher during strong-motion earthquakes will be essentially unaffected by any degree of foundation compliance that can be expected in normal building practice. The fundamental period of typical buildings will be increased by about 10 per cent if the foundation compliance is the maximum that can be expected in standard building practice.


1985 ◽  
Vol 1 (2) ◽  
pp. 239-270 ◽  
Author(s):  
Jogeshwar P. Singh

Until recently, characteristics of strong ground motion resulting from different soil conditions were considered the dominant factor in developing design ground motions and reconciling observed damage. Interpretation of recent recordings of earthquakes by strong motion instrument arrays installed in California and Taiwan show that basic characteristics of strong motion are greatly influenced by the seismological and geological conditions. For a given soil condition, the characteristics of strong ground motion (peak ground acceleration, peak ground velocity, peak ground displacement, duration, spectral content, and time histories) can vary significantly whether the site is near or far from the seismic source. As local soil conditions only modify the ground motions produced by a given source, variability in ground motion due to seismologic and geologic conditions (for a given soil condition) must be considered in estimating earthquake ground motions for structural design or for estimating structural vulnerabilities to reconcile earthquake-related damage.


2009 ◽  
Vol 25 (3) ◽  
pp. 497-514 ◽  
Author(s):  
Maren Böse ◽  
Vladimir Sokolov ◽  
Friedemann Wenzel

We establish and test a shake map methodology for intermediate-depth Vrancea earthquakes, based on seismological information gathered in Romania during recent years. We use region- (azimuth-) dependent attenuation relations derived from stochastic simulations of ground motions using spectral models of Vrancea earthquakes. Both region boundaries and Fourier amplification spectra for the characterization of seismic site effects are based on several hundred weak, moderate and strong-motion records and macroseismic intensity maps. We determine region-specific, magnitude- and distance-dependent amplification factors of peak values and instrumental intensity relative to rock. We interpolate recorded ground motions and ground motion estimates from the obtained amplification factors and attenuation relations for rock conditions. The resulting shake maps show a good agreement with macroseismic descriptions of moderate-sized and large Vrancea earthquakes, demonstrating the feasibility of a seismological approach to shake map generation. Unlike previous methodologies, this approach requires neither expensive assessments of geology-dependent site amplification factors, nor large numbers of strong-motion records. Our results are in good agreement with empirical topographic slope-site amplification relations, but give a better reflection of the abnormal attenuation of seismic waves in the Transylvanian region and the strong amplification in the Focsani basin.


2019 ◽  
Vol 32 (3-4) ◽  
pp. 115-124
Author(s):  
Peng Tian ◽  
◽  
Xiaodan Sun ◽  
Xin Li ◽  
Keyu Wan

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