Shock Induced Damage onto Free-Standing Objects in an Earthquake
In areas of low to moderate seismicity many building contents and equipment are not positively fixed to the floor or tied to adjacent walls. Under seismic induced horizontal vibration, such contents and equipment can suffer from damage by either overturning or impact associated with rocking. This paper focuses on the estimation of shock on typical contents and equipment due to rocking. A simplified analytical model is outlined that can be used to estimate the maximum acceleration on a rocking object given its basic geometric and mechanical properties. The developed model was validated against experimental results. The experimental results revealed that the maximum shock acceleration can be underestimated if the static stiffness of the materials at the interface between the rocking object and floor is used rather than the dynamic stiffness. Excellent agreement between the model and experimental results was found when the dynamic stiffness for the interface material was used, which was found to be generally much higher than corresponding static stiffness under different investigated boundary conditions of the cushion. The proposed model can be a beneficial tool in performing a rapid assessment of shock sensitive components considered for possible seismic rectification.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1056378Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF
 FEMA 356,Prestandard and Commentary for Seismic Rehabilitation of Buildings. Prepared by the American Society of Civil Engineers for the Federal Emergency Management Agency. FEMA, 2000.
 IBC, International Code Council. International building Code, U.S.A., 2000.
 AS/NZS 1170.4, Australian Standard for Structural Design Actions, Part 4: Earthquake Actions in Australia. 2005.
 G.W.Housner, "The Behaviour of inverted pendulum structures,”Bulletin of the Seismological Society of America, 53 (2), 403- 417. 1963.
 S.C.S.Yim, A.K.Chopra, and J.Penzien, “Rocking Response of Rigid Blocks to Earthquakes,” Earthquake Engineering and Structural Dynamics 122(7), 69093. 1980.
 M.Aslam, W.G.Godden, and D.T.Scalise, “Earthquake rocking response of rigid bodies,” Journal of the Structural Division, 106, 377-392, 1980.
 Y.Ishiyama, "Motions of rigid bodies and criteria for overturning by earthquake excitations,"Earthquake Engineering and Structural Dynamics, 10, pp. 635-650. 1982.
 S.J.Hogan,“On the dynamics of rigid-block motion under harmonic motion,” Proc. R. Soc. Lond, 425, 441-476. 1989.
 P. R. Lipscombe, Dynamics of rigid block structures. Ph.D. thesis, University of Cambridge, 1990.
 N. Makris and Y.Roussos, “Rocking Response and Overturning of Equipment Under Horizontal Pulse-Type Motions,” Pacific Earthquake Engineering Research Center PEER 1998, Report No. 5, 1998.
 N.Makris and D.Konstantinidis, “The Rocking Spectrum and the Shortcomings of Design Guidelines,” Pacific Earthquake Engineering Research Center PEER 2001, Report No. 7, 2001.
 H.Al Abadi, Unrestrained Building Contents in Regions of Low- Moderate Seismicity. Ph.D. thesis, Civil Engineering Dept., The University of Melbourne, Melbourne, 2008.
 H. Al Abadi, N.Lam, and E.Gad, “A simple displacement-based model for predicting seismically induced overturning,” Journal of Earthquake Engineering, 2006 10(6), 775–814, 2006.
 H.Al Abadi, N.T.K.Lam, E.F.Gad, and A.M.Chandler, “Earthquake Floor Spectra for Unrestrained Building Components,” International Journal of Structural Stability and Dynamics, 4 (3), 361-377, 2004.
 D.Franke, N.Lam, E.Gad, and A.Chandler, “Seismically Induced Overturning of Objects and Filtering Effects of Buildings,” International Journal of Seismology and Earthquake Engineering, 7 (2), 95-108, 2005.
 B.Kafle, N.Lam, E.Gad, and J.Wilson, "Displacement controlled rocking behaviour of rigid objects," Earthquake Engineering and Structural Dynamics, 40, 1653-1669, 2011.
 N.Lam, M.Griffith, J. Wilson, and K. Doherty, "Time History Analysis of URM walls in out-of-plane flexure," Journal of Engineering Structures, 25 (6), 743-754, 2003.
 M.C.Griffith, N.T.K. Lam, J.L. Wilson, and K.Doherty, "Experimental Investigation of Unreinforced Brick Masonry Walls in Flexure," Journal of Structural Engineering, 130(3), 423-432, 2004.
 K.Doherty, M.Griffith, N.T.K. Lam, and J.L.Wilson, “Displacement- Based Analysis for out-of plan bending of seismically loaded unreinforced masonry walls,” Earthquake Engineering and Structural Dynamics, 31(4), 833-850, 2002.
 E.Lumantarna, N.T.K. Lam, J.L.Wilson, and M.C.Griffith, "Inelastic Displacement Demand of Strength Degraded Structures,”Journal of Earthquake Engineering, 14: 487-511, 2010.
 N.T.K.Lam and E.G.Gad, "Overturning of Non-structural Components in Low-moderate Seismicity Regions. Special Issue on Earthquake Engineering in Low-Moderate Seismicity Regions of Southeast Asia and Australia," Electronic Journal of Structural Engineering, 121-132. 2008.
 S.Goyal, E. K. Buratynski, and G. W. Elko,"Role of Shock Response Spectrum in ElectronicProduct Suspension Design," The International Journal of Microcircuits and Electronic Packaging, vol. 23, no. 2, pp. 182-190, Second Quarter2000.
 H.Al Abadi, N.Lam, E.Gad, and J. Petrolito, “A Simple Model for Estimating Shocks in Unrestrained Building Contents in an Earthquake,” Journal of Earthquake Engineering,in press.
 M.Avalle, G. Belingardi, and R. Montanini,“Characterization of polymeric structural foams under compressive impact loading by means of energy-absorption diagram,”International Journal of Impact Engineering, 25, 455-472, 2001.
 R.R.A.Cousins, “Theory of the Impact Behaviour of Rate-Dependent Padding Materials,”Journal of Applied Polymer Science, 20, 2893-2903, 1976.
 O.Ramon and J.Miltz, “Prediction of Dynamic Properties of Plastic Foams from Constant-Strain Rate Measurements,” Journal of Applied Polymer Science, 40, 1683-1692, 1990.
 R.W.Shuttleworth, V.O.Shestopal, and P.C.Goss, “Open-Cell Flexible Polyurethane Foams: Comparison of Static and Dynamic Compression Properties,” Journal of Applied Polymer Science, 30, 333-343, 1985.