Shaking Table Performance of a New Bridge System with Pretensioned Rocking Columns

Thonstad, Travis; Mantawy, Islam M.; Stanton, John F.; Eberhard, Marc O.; Sanders, David H.

doi:10.1061/(asce)be.1943-5592.0000867

Cited by 85 publications

(51 citation statements)

References 17 publications

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“…However, this problem is already solved (to some extent) by researchers who focused on tendonrestrained concepts: Thonstad et al (2016) have extended the column via a reduced diameter part that was fitted into a smaller void in the cap beam, while Mashal and Palermo (2017) used external shear keys welded to the steel jackets and the base plates protecting the supporting foundation from crushing. The rocking piers concept is also compatible with prefabrication, as it only requires dry connections and minimizes on-site construction time.…”

Section: Rocking Piers Conceptmentioning

confidence: 99%

“…As shown in Figure 4C, the piers are modeled with solid elements (instead of beam elements) in order to simulate the rocking interface, where plane sections are not expected to remain plane (Avgenakis and Psycharis, 2017). The pier ends of the actual structure would be protected with steel jackets and no concrete spalling would be expected as it was observed in experimental testing (Thonstad et al, 2016;Mashal and Palermo, 2017). Therefore, elastic concrete material is used to model the piers.…”

Section: Rocking Piers Modelmentioning

confidence: 99%

“…A large friction coefficient μ = 10 is assumed for the pier-deck interface, to prohibit sliding of the bearings, allowing only opening or closure of the joint. In reality, a recess or another similar constraint should be implemented to prohibit sliding (Thonstad et al, 2016;Mashal and Palermo, 2017). Special contact elements are introduced between the piers and the footings, allowing uplifting but prohibiting sliding by assuming a large friction coefficient μ = 10 (to ensure purely rocking response of the piers).…”

Section: Rocking Piers Modelmentioning

confidence: 99%

See 2 more Smart Citations

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 Piers Conceptmentioning

confidence: 99%

Section: Rocking Piers Modelmentioning

confidence: 99%

Section: Rocking Piers Modelmentioning

confidence: 99%

See 1 more Smart Citation

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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“…The synchronization control will keep the shaking tables moving synchronously even though there is large attitude control error or it is out of control. Based on the synchronization control, the tracking control precision also needs to be Generally, the experiment specimen of the shaking table is the civil engineering structure, which is mostly reinforced concrete structure [5,6]. As we all know, the reinforced concrete structure specimen is easily damaged when the specimen encounters large deformation.…”

Section: Control Scheme Designmentioning

confidence: 99%

“…Mechanical test and simulation (MTS) corporation built the two horizontal directions shaking tables system for the University of Nevada, Reno in 2003 [3] and built the Six-degree of freedom (DOF) shaking tables system for University of Buffalo, state university of New York (SUNY) in 2003 [4]. Many large-span structure earthquake simulation experiments have been successfully performed, which indicates the superiority of the shaking tables system in the experimental research [5,6].…”

Section: Introductionmentioning

confidence: 99%

Optimal Design and Hybrid Control for the Electro-Hydraulic Dual-Shaking Table System

et al. 2016

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This paper is to develop an optimal electro-hydraulic dual-shaking table system with high waveform replication precision. The parameters of hydraulic cylinders, servo valves, hydraulic supply power and gravity balance system are designed and optimized in detail. To improve synchronization and tracking control precision, a hybrid control strategy is proposed. The cross-coupled control using a novel based on sliding mode control based on adaptive reaching law (ASMC), which can adaptively tune the parameters of sliding mode control (SMC), is proposed to reduce the synchronization error. To improve the tracking performance, the observer-based inverse control scheme combining the feed-forward inverse model controller and disturbance observer is proposed. The system model is identified applying the recursive least squares (RLS) algorithm and then the feed-forward inverse controller is designed based on zero phase error tracking controller (ZPETC) technique. To compensate disturbance and model errors, disturbance observer is used cooperating with the designed inverse controller. The combination of the novel ASMC cross-coupled controller and proposed observer-based inverse controller can improve the control precision noticeably. The dual-shaking table experiment system is built and various experiments are performed. The experimental results indicate that the developed system with the proposed hybrid control strategy is feasible and efficient and can reduce the tracking errors to 25% and synchronization error to 16% compared with traditional control schemes.

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Displacement‐based analysis and design of rocking structures

Manzo

Vassiliou

2019

Earthq Engng Struct Dyn

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Summary The response of a rigid rocking block is traditionally described by its tilt angle. This is a correct description, but this paper suggests that describing rocking via displacements is more meaningful, because it uncovers that two geometrically similar blocks of different size will experience the same top displacement, provided that they are not close to overturn. The above is illustrated for both analytical pulse excitations and for recorded ground motions. Thus, the displacement demand of a ground motion on a rocking block is only a function of its slenderness, not of its size. This reduces the dimensionality of the problem and allows for the construction of size‐independent rocking demand spectra.

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Shaking Table Performance of a New Bridge System with Pretensioned Rocking Columns

Cited by 85 publications

References 17 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

Optimal Design and Hybrid Control for the Electro-Hydraulic Dual-Shaking Table System

Displacement‐based analysis and design of rocking structures

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