Seismic response of elastic multidegree of freedom oscillators placed on the top of rocking storey

Bantilas, Kosmas E.; Kavvadias, Ioannis E.; Vasiliadis, Lazaros K.

doi:10.1002/eqe.3400

Cited by 22 publications

(52 citation statements)

References 41 publications

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“…In the rolling/rocking response of rigid blocks, energy dissipation occurs during impact when the tilt angle of the rocking columns reverses the sign. The solution of the impact problem results in the coefficient of restitution of the rocking base as well as in the post‐impact velocities of the floors of the superstructure as follows 33 :

c = {((), \frac{{\dot{θ}}^{+}}{{\dot{θ}}^{-}})}^{2} = {([] 1 - 2 \sin^{2} α \frac{1 + 4 γ (1 + η)}{{\overset{I}{true}}_{o} + 4 γ (1 + η)})}^{2} and {\overset{u}{true}}_{boldt}^{+} = {\overset{u}{true}}_{boldt}^{-} - bold-italicδ 2 R \cos α (1 - \sqrt{c}) {\overset{θ}{true}}^{-}

where

{\dot{boldu}}_{t}^{-}

and

{\dot{boldu}}_{t}^{+}

are the superstructure's absolute velocity vectors before (−) and after (+) impact, respectively.…”

Section: Dynamic Response Of Rocking Podium Structuresmentioning

confidence: 99%

“…Regarding the superstructure, the maximum base shear (V Pod ) could be a proper EDP. Previous studies have been pointed out that the magnitude of the seismic demands of the superstructure in RPSs is almost constant and depends mainly on the slenderness of the rocking columns 32,33 . However, in order to characterize the rocking base as a seismic isolation system, the reduction of the elastic demands should be examined.…”

Section: Fragility Assessmentmentioning

confidence: 99%

“…Based on the sdof model of the superstructure, Bantilas et al 32 investigated the parameters that affect the elastic demands of RPSs. Later studies of Bantilas et al 33 highlighted the critical effect of impact on the dynamic response of RPSs consisted of multiple degrees of freedom (mdof) elastic superstructure. Due to the coupling between rocking and elastic vibrations, RPSs present a more complex response compared to solely rocking oscillators.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Seismic fragility and intensity measure investigation for rocking podium structures under synthetic pulse‐like excitations

Bantilas

Kavvadias

Vasiliadis

et al. 2021

Earthq Engng Struct Dyn

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Rocking podium structures (RPSs) refer to a wide class of structural systems in which the base storey consisting of freestanding columns that can uplift during seismic excitations. Due to the rocking response, the base storey can be considered as a base isolation system on the condition that a rocking overturn is prevented. In the present study, the seismic response of RPSs is assessed within a probabilistic framework. For this purpose, synthetic pulse‐like acceleration records are generated. The performance of several ground motion intensity measures in predicting the rocking response of RPSs with different superstructure's fundamental period, lateral displacement profiles and rocking column configuration are examined. The effect of these structural parameters on the rocking response is evaluated in terms of seismic fragility. Finally, the seismic behaviour of the rocking storey, as a seismic isolation technique, is evaluated by examining both the rocking stability and the seismic demand reduction of the superstructure simultaneously.

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c = {((), \frac{{\dot{θ}}^{+}}{{\dot{θ}}^{-}})}^{2} = {([] 1 - 2 \sin^{2} α \frac{1 + 4 γ (1 + η)}{{\overset{I}{true}}_{o} + 4 γ (1 + η)})}^{2} and {\overset{u}{true}}_{boldt}^{+} = {\overset{u}{true}}_{boldt}^{-} - bold-italicδ 2 R \cos α (1 - \sqrt{c}) {\overset{θ}{true}}^{-}

where

{\dot{boldu}}_{t}^{-}

and

{\dot{boldu}}_{t}^{+}

are the superstructure's absolute velocity vectors before (−) and after (+) impact, respectively.…”

Section: Dynamic Response Of Rocking Podium Structuresmentioning

confidence: 99%

Section: Fragility Assessmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Seismic fragility and intensity measure investigation for rocking podium structures under synthetic pulse‐like excitations

Bantilas

Kavvadias

Vasiliadis

et al. 2021

Earthq Engng Struct Dyn

Self Cite

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show abstract

“…On the other hand, rocking design allows the structure to uplift and pivot during an earthquake relieving the structure from stresses and subsequently seismic damage. The seminal work of Housner [1] first revealed the benefits of rocking design over the conventional (fixed-base) design after the Chilean earthquake in 1960, and many studies have followed [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17], among others.…”

Section: Introductionmentioning

confidence: 99%

Quantifying Seismic Resilience of Single-Column Rocking Bridges – A Comparative Study

Giouvanidis¹,

Dong²

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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This study focuses on structural systems which are particularly attractive for bridge design. Specifically, it investigates the seismic performance of single-column bridges, which are either conventionally designed, with the column monolithically connected with the ground (i.e. fixed-base), or designed with the column-footing system able to uplift and exhibit planar rocking motion during an earthquake. Conventionally designed bridges sustain considerable damage at the column ends after severe earthquakes. Seismic damage often determines whether the bridge remains functional after a seismic event. On the contrary, rocking design implies that a structure under seismic loading performs rigid body rotation around pre-defined pivot points. Thus, in principle, it relieves the structure from excessive deformations and damage. However, rocking isolation is not often applied in bridge engineering practice, mainly due to the lack of thorough understanding of its dynamic (seismic) performance and its potential post-earthquake financial benefits. This paper redirects our attention to the main benefits of rocking design over the conventional (fixed-base) design and conducts a comparative study between the two design methodologies in terms of their seismic losses and resilience in the aftermath of severe seismic hazard scenarios. The analysis reveals the mitigated seismic losses and the remarkable resilience that rocking design offers compared to the conventional (fixed-base) design after all the examined seismic hazard scenarios. The above findings reinforce the potential of the rocking design as an alternative seismic design paradigm for future bridge engineering applications and serve as the basis for a more rational and holistic seismic assessment of single-column rocking bridges.

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“…Rocking is also a promising seismic response modification technique, both for bridges and buildings, with limited practical applications in the former USSR and New Zealand [20,21]. Applications in buildings may comprise a soft-rocking-story mechanism [22][23][24], or a rocking wall [25,26], whereas in bridges, rocking piers [27][28][29][30][31][32][33][34][35]. Several analytical studies investigated the response of rocking structures combined with external dampers or…”

Section: Introductionmentioning

confidence: 99%

Shake table statistical validation of Finite Element models of rocking structures

Katsamakas¹,

Vassiliou²

2021

1st Croatian Conference on Earthquake Engineering

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This paper presents a three-dimensional finite element (FE) modeling approach for predicting the response of rocking columns. The model is validated against experimental results, which involved testing three different cylindrical columns with different slenderness ratios under a set of 100 bidirectional ground motions. Each column was free-standing and allowed to slide and rock in all directions. Since the developed stresses in the columns were low, all columns were modeled as rigid.The contact surface was simulated using Coulomb friction for the tangential behavior and stiff contact for the normal direction. Two energy dissipation mechanisms were modeled; friction and radiation damping. Inherent numerical damping, as well as Rayleigh damping, were set to zero, with this approach complying to the physical problem.Rocking is characterized as a chaotic and unpredictable problem, with tests being non-repeatable. Therefore, this study employs a statistical approach to validate the numerical results, using the cumulative distribution function (CDF) for the main response quantity (i.e., maximum top displacement of the column). It was proved that the model performs poorly in the deterministic validation but demonstrates satisfying agreement with the experimental results when validated statistically.The influence of the main modeling parameters, meaning the friction coefficient and the radiation damping properties, was assessed through an extensive sensitivity analysis using non-linear time-history analyses. A small change of the value of these parameters leads to a different individual rocking oscillation but only smoothly influences the statistical response.

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Seismic response of elastic multidegree of freedom oscillators placed on the top of rocking storey

Cited by 22 publications

References 41 publications

Seismic fragility and intensity measure investigation for rocking podium structures under synthetic pulse‐like excitations

Seismic fragility and intensity measure investigation for rocking podium structures under synthetic pulse‐like excitations

Quantifying Seismic Resilience of Single-Column Rocking Bridges – A Comparative Study

Shake table statistical validation of Finite Element models of rocking structures

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