An analytical model of a deformable cantilever structure rocking on a rigid surface: experimental validation

Truniger, Rico; Vassiliou, Michalis F.; Stojadinović, Božidar

doi:10.1002/eqe.2609

Cited by 63 publications

(105 citation statements)

References 16 publications

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“…The change of pivot point is sometimes fast, but it is only scarcely instantaneous, as first observed by Srinivasan and Ruina (2008) and confirmed by Vassiliou et al (2017b). Figure 11 shows that 3D wobbling motion avoids the very large spikes in the moment time history that planar rocking structures experience (Oliveto et al, 2003;Acikgoz and DeJong, 2012;Truniger et al, 2015;Giouvanidis and Dimitrakopoulos, 2017b). Spikes do occur, at every fast (but not instantaneous) change of pivot point, but their magnitude is clearly smaller than the ones observed in planar motion and are always smaller than the moment strength of the pier (even when they are vectorially added), as shown in Figure 11.…”

Section: Rocking Piersmentioning

confidence: 62%

Comparative Assessment of Two Rocking Isolation Techniques for a Motorway Overpass Bridge

Agalianos

Psychari

Vassiliou

et al. 2017

Front. Built Environ.

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Rocking isolation of structures is evolving as an alternative design concept in earthquake engineering. The present paper investigates the seismic performance of an actual overpass bridge of the Attiki Odos motorway (Athens, Greece), employing two different concepts of rocking isolation: (a) rocking of the piers on the foundation (rocking piers); and (b) rocking of the pier and foundation assembly (rocking footings) on the soil. The examined bridge is an asymmetric 5-span system having a continuous deck and founded on surface foundations on a deep clay layer. The seismic performance of the two rocking-isolated bridges is comparatively assessed to the existing bridge, which is conventionally designed according to current seismic design codes. To that end, 3D numerical models of the bridge-foundation-abutment-soil system are developed, and both static pushover and non-linear dynamic time history analyses are performed. For the latter, an ensemble of 20 records (10 ground motions of 2 perpendicular components each) that exceed the design level are selected. The conventional system collapses in 5/10 of the (intentionally severe) examined seismic excitations. The rocking piers design alternative survives in 8/10 of the cases examined, with negligible residual deformations. The safety margins of the rocking footings design concept are even larger, as it survives in all cases examined. Both rocking isolation concepts are proven to offer increased levels of seismic resilience, reducing the probability of collapse and the degree of structural damage. Nevertheless, in the rocking piers design alternative high stress concentrations at the rotation pole (pier base) are developed, indicating the need for a special design of the pier ends. This is not the case for the rocking footings concept, which however is subject to increased residual settlements but no residual rotations.

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Section: Rocking Piersmentioning

confidence: 62%

Comparative Assessment of Two Rocking Isolation Techniques for a Motorway Overpass Bridge

Agalianos

Psychari

Vassiliou

et al. 2017

Front. Built Environ.

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“…Many researchers have revisited the above assumption [23,25,35,[43][44][45] and formulated more detailed expressions. In this study the Housner coe cient of restitution will be used due to the following:…”

Section: Employed Numerical Modelmentioning

confidence: 99%

“…Researchers that have tried to experimentally validate Housner's model [20][21][22][23][24][25][26] have shown that, given the modelling uncertainty (especially of the one related to impact), it is di cult to confidently predict the time history response of a rocking block to a specific ground motion. Even if the coe cient of restitution is relatively well predicted, or determined via experiments, the response of the system to a ground motion is so sensitive that predicting the whole time history is practically impossible [27].…”

Section: Introductionmentioning

confidence: 99%

Probabilistic Validation of the Housner Rocking Model

Bachmann¹,

Strand²,

Vassiliou³

et al. 2017

Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Abstract.The rocking oscillator has drawn the attention of many researchers since the publication of Housner's [1] seminal paper. As the response of the rocking oscillator is highly non-linear and exhibits negative sti↵ness [2] many researchers have suggested treating the rocking oscillator as a chaotic system, in the sense that small perturbations of its governing parameters result to widely diverging outcomes. Researchers that have tried to experimentally validate Housner's model have shown that, given the modelling uncertainty, it is hard to confidently predict the time history response of a rocking block to a specific ground motion. This makes practicing engineers hesitant to adopt rocking as an earthquake response modification strategy.However, accurately predicting the response to a single ground motion would be ideal but it is not a necessary condition to trust a model: there is so much uncertainty in the expected ground motion that could overshadow the modelling uncertainty. To take the former uncertainty into account, in common practice, engineers use an ensemble of ground motions when they perform a time history analysis. Therefore, it is reasonable to try to compare numerical experimental testing results in terms of their statistics. If the numerical model is capable of capturing the statistics of the experimental testing, then, in terms of civil engineering design, the model is trustworthy. The first ones to adopt a probabilistic approach were Yim, Chopra and Penzien [3] who as early as in 1980 observed some order in rocking motion when they studied it from a probabilistic point of view. They observed specific trends in their numerical results when, instead of using only one, they used 10 synthetic ground motions. This paper compares the numerical and experimental response of a rigid rocking block when excited by an ensemble of 100 ground motions that share the statistical properties of original ground motion.

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“…Indeed, a simple freestanding rocking block has been systematically studied for more than five decades both when the block is assumed rigid [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and when it assumed deformable [27][28][29][30][31][32][33][34][35][36][37]. Small scale experiments have been also performed [38][39][40][41][42][43][44][45][46][47][48][49][50][51]. It has been proven that structures that rock inplane (2d rocking) have remarkable dynamic stability.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Response of a Rigid Slab Supported by Four Rigid Cylinrical Rocking and Wobbling Columns

Rajah¹,

Bachmann²,

Vassiliou³

et al. 2017

Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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An analytical model of a deformable cantilever structure rocking on a rigid surface: experimental validation

Cited by 63 publications

References 16 publications

Comparative Assessment of Two Rocking Isolation Techniques for a Motorway Overpass Bridge

Comparative Assessment of Two Rocking Isolation Techniques for a Motorway Overpass Bridge

Probabilistic Validation of the Housner Rocking Model

Dynamic Response of a Rigid Slab Supported by Four Rigid Cylinrical Rocking and Wobbling Columns

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