Approximate formulas for rotational effects in earthquake engineering

The paper addresses the issue of researching into the engineering characteristics of rotational strong ground motion components and rotational effects in structural response. In this regard, at first, the acceleration response spectra of rotational components are estimated in terms of translational ones. Next, new methods in order to consider the effects of rotational components in seismic design codes are presented by determining the effective structural parameters in the rotational loading of structures due only to the earthquake rotational components. Numerical results show that according to the frequency content of rotational components, the contribution of the rocking components to the seismic excitation of short period structures can never be ignored. During strong earthquakes, these rotational motions may lead to the unexpected overturning or local structural damages for the low-rise multi-story buildings located on soft soil. The arrangement of lateral-load resisting system in the plan, period, and aspect ratio of the system can severely change the seismic loading of wide symmetric buildings under the earthquake torsional component.

[1]  Heiner Igel,et al.  The Effect of Torsional Ground Motion on Structural Response: Code Recommendation for Accidental Eccentricity , 2009 .

[2]  Mihailo D. Trifunac,et al.  The role of strong motion rotations in the response of structures near earthquake faults , 2009 .

[3]  N. Newmark.  TORSION IN SYMMETRICAL BUILDINGS , 1969 .

[4]  Empirical Scaling of Rotational Spectra of Strong Earthquake Ground Motion , 2009 .

[5]  Juan Carlos de la Llera,et al.  Accidental torsion in buildings due to base rotational excitation , 1994 .

[6]  H. Shakib,et al.  EVALUATION OF ACCIDENTAL ECCENTRICITY IN BUILDINGS DUE TO ROTATIONAL COMPONENT OF EARTHQUAKE , 2002 .

[7]  Mihailo D. Trifunac,et al.  A note on rotational components of earthquake motions on ground surface for incident body waves , 1982 .

[8]  Erol Kalkan,et al.  Coupled Tilt and Translational Ground Motion Response Spectra , 2007 .

[9]  J. Pujol.  Tutorial on Rotations in the Theories of Finite Deformation and Micropolar (Cosserat) Elasticity , 2009 .

[10]  Arthur C. Heidebrecht,et al.  Response spectra for torsion, rocking and rigid foundations , 1985 .

[11]  Mahendra P. Singh,et al.  Structural response for six correlated earthquake components , 1986 .

[12]  Hong-Nan Li,et al.  Improved approach for obtaining rotational components of seismic motion , 2004 .

[13]  W. K. Tso,et al.  STATIC ECCENTRICITY CONCEPT FOR TORSIONAL MOMENT ESTIMATIONS , 1990 .

[14]  H. Hao.  CHARACTERISTICS OF TORSIONAL GROUND MOTIONS , 1996 .

[15]  B. Souter,et al.  The effect of block rotations on the global seismic moment tensor and the patterns of seismic P and T axes , 1993 .

[16]  M. Ghayamghamian,et al.  On the characteristics of ground motion rotational components using Chiba dense array data , 2007 .

[17]  Zbigniew Zembaty,et al.  Rotational Seismic Load Definition in Eurocode 8, Part 6, for Slender Tower-Shaped Structures , 2009 .

[18]  Anil K. Chopra,et al.  Elastic Earthquake Analysis of a Class of Torsionally Coupled Buildings , 1977 .

[19]  W. K. Tso,et al.  Seismic torsional provisions for dynamic eccentricity , 1980 .