An equivalent accidental eccentricity to account for the effects of torsional ground motion on structures

2014 ◽  
Vol 69 ◽  
pp. 1-11 ◽  
Author(s):  
Dhiman Basu ◽  
Michael C. Constantinou ◽  
Andrew S. Whittaker
Keyword(s):  
Ground Motion ◽  
Accidental Eccentricity ◽  
Torsional Ground Motion

scholarly journals Seismic torsional effects on buildings

1976 ◽  
Vol 9 (1) ◽  
pp. 79-83 ◽  
Author(s):  
D. G. Elms
Keyword(s):  
New Zealand ◽  
Ground Motion ◽  
Building Structures ◽  
The Third ◽  
Accidental Eccentricity ◽  
Parabolic Function ◽  
Torsional Ground Motion

This paper gives the background to the seismic torsional provisions of the New Zealand Loadings Code. These provisions attempt to deal with three effects: accidental eccentricity, torsional ground motion, and coupling between torsional and translational modes. The first two effects lead to an effective eccentricity of one-tenth of the width of a building, while the third leads to a parabolic function of the calculated eccentricity: this was obtained by applying existing results for torsional amplification to a number of typical building structures.

Rotational Components of Earthquake Motion

1975 ◽  
Vol 2 (4) ◽  
pp. 430-436 ◽  
Author(s):  
N. D. Nathan ◽  
J. R. MacKenzie
Keyword(s):  
Ground Motion ◽  
Earthquake Motion ◽  
Rotational Components ◽  
Earthquake Record ◽  
Code Provisions ◽  
Torsional Ground Motion

Following the ideas of Newmark, a complete record of torsional ground motion is generated from the two translational components of an earthquake record. The approximate spectra developed by Newmark are generally confirmed. The assumptions and the limits of validity are discussed. Code provisions for this phenomenon are commented upon.

Rotational ground motion and seismic codes

1985 ◽  
Vol 12 (3) ◽  
pp. 583-592 ◽  
Author(s):  
A. Rutenberg ◽  
A. C. Heidebrecht
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Response Spectra ◽  
Travelling Wave ◽  
Building Code ◽  
Rotational Ground Motion ◽  
Torsional Response ◽  
Accidental Eccentricity ◽  
Wave Effects ◽  
Effective Phase

The primary purpose of this paper is to discuss the separation of travelling wave effects from the mass center to resistance center eccentricity effects, and to propose means by which the torsional spectrum (or a torsional seismic factor) could be incorporated in the seismic provisions of the National Building Code of Canada. The paper begins the treatment of the subject matter by presenting a detailed review of previous work on the effects of torsional ground motion, emphasizing the methods which have been proposed to develop torsional response spectra. The travelling wave assumption is critically reviewed and the effective phase velocities applicable for design purposes are discussed. This is followed by a simple analysis showing how the torsional spectra can be derived directly from the corresponding translational response spectra. Formulae separating the torsional input effects from the accidental eccentricity effects are presented and discussed. Finally, it is shown how the torsional spectrum can be incorporated within the framework of the response spectrum procedure of the 1985 edition of the National Building Code of Canada. Key words: seismic, earthquake, structure, dynamic, rotation, code, torsion, foundation, eccentricity, response spectrum, acceleration, velocity, design.

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