Abstract
The rocking (overturning) instability of one and two rigid—block assemblies underground motion of sinus and cosinus pulses is reconsidered. The Housner effect according to which between two geometrically similar (rectangular) rigid blocks, the taller is more stable (than the lower one) is extended to the case where between two rigid blocks having the same width, the taller is generally more stable. It was also found that overturning for one rigid block (1-DOF) system without or after one impact occurs through an unstable equilibrium (saddle) point via an escaped motion (inflection point in the curve relating the unknown rotation to the time). Such a critical state happens always during a free motion regime regardless of whether impact occurs before or after the external excitation expires. The condition of overturning after one impact (occurring after the external excitation expires) was established through one elegant equation which relates directly the minimum amplitude ground excitation to the external frequency. For a two-rigid block (2-DOF) system overturning without or after impact (associated with a minimum amplitude ground excitation) occurs in the upper rigid block according to the aforementioned inflection point criterion. All linearized results were also verified via non-linear numerical analysis, properly adjusted to include the rotational friction of the block pivot axis at the rocking initiation.
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References
Konstantinidis D, Makris N (2005) Seismic response analysis of multidrum classical columns. Earthq Eng Struct Dyn 34:1243–1270
Kounadis AN (2015) On the rocking complex response of ancient multispondyle columns: a genious and challenging structural system requiring reliable solution. Meccanica 50:261–292
Kounadis AN, Papadopoulos GJ, Cotsovos DM (2012) Overturning instability of a two rigid block system under ground excitation. ZAMM Z Angew Math Mech 92(7):536–557
Kounadis AN, Papadopoulos GJ (2016) On the rocking instability of a three—rigid block system under ground excitation (to be submitted)
Kounadis AN (2014) Rocking instability of free-standing statues atop slender viscoelastic columns under ground motion. Soil Dyn Earthq Eng 63:83–91
Spanos PD, Koh A-S (1984) Rocking of rigid blocks due to harmonic shaking. J Eng Mech ASCE 110(11):1627–1642
Shenton HW (1996) Criteria for initiation of slide, rock, and slide-rock rigid-body modes. J Eng Mech ASCE 122(7):690–693
Allen RH, Oppenheim IJ, Parker AR, Bielak J (1986) On the dynamic response of rigid body assemblies. Earthq Eng Struct Dyn 14:861–876
Zhang J, Makris N (2001) Rocking response of free-standing blocks under cycloid pulses. J Eng Mech ASCE 127:473–483
Kounadis AN (2010) On the overturning instability of a rectangular rigid block under ground excitation. Open Mech J 4:43–57
Kounadis AN (2013) Parametric study in rocking instability of a rigid block under harmonic ground pulse: a unified approach. Soil Dyn Earthq Eng 45:125–143
Psycharis ΙΝ (1990) Dynamic behaviour of rocking two-block assemblies. Earthq Eng Struct Dyn 19(4):555–575
Housner GW (1963) The behavior of inverted pendulum structure during earthquakes. Bull Seismol Soc Am 53(2):403–417
Andreaus U (1990) Sliding-uplifting response of rigid blocks to base excitation. Earthq Eng Struct Dyn 19(8):1181–1196
Andreaus U, Casini P (1999) Dynamics of three rigid block assemblies with unilateral deformable contacts. Part 1: contact modelling. Earthq Eng Struct Dyn 28(12):1621–1636
Andreaus U, Casini P (1999) Dynamics of three rigid block assemblies with unilateral deformable contacts. Part 2: sample application. Earthq Eng Struct Dyn 28(12):1637–1649
Lenci S, Rega G (2006) A dynamical systems approach to the overturning of rocking blocks. Chaos Solitons Fractals 28(2):527–542
Voyagaki E, Psycharis IN, Mylonakis G (2014) Complex response of a rocking block to a full-cycle pulse. J Eng Mech 140(6):1–15
Chatzis MN, Smyth AW (2011) Robust modeling of the rocking problem. J Eng Mech 138(3):247–262
Zhang H, Brogliato B, Liu C (2014) Dynamics of planar rocking-blocks with Coulomb friction and unilateral constraints: comparisons between experimental and numerical data. Multibody Sys Dyn 32(1):1–25
Konstadinidis D, Makris N (2005) Experimental and analytical studies on the seismic response of free-standing and anchored laboratory equipment, Pacific Earthquake. Engineering Research Centre, PEER REPRT 2005/07, January 2005, College of Engineering. University of California, Berkeley
Drosos V, Anastasopoulos I, Gazetas G (2012) Seismic behaviour of classical columns: an experimental study, Laboratory of Soil Mechanics Research Report: LSM. NTUA.-12-01
Wolfram S (2003) The mathematica book, 5th edn. Wolfram Media, Champaign, IL
Kounadis AN (2015) On the rocking-sliding instability of rigid blocks under ground excitation: some new findings. Soil Dyn Earthq Eng (accepted)
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Kounadis, A.N. New findings in the rocking instability of one and two rigid block systems under ground motion. Meccanica 50, 2219–2238 (2015). https://doi.org/10.1007/s11012-015-0167-3
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DOI: https://doi.org/10.1007/s11012-015-0167-3