Steel frames with bracing mechanism and hysteretic dampers

Phocas, Marios C.; Pocanschi, Adrian

doi:10.1002/eqe.253

Cited by 39 publications

(12 citation statements)

References 6 publications

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“…A number of studies have been carried out to propose new tension braces to avoid pinching. These studies can be roughly classified into the following two groups: In one group, mechanical devices were devised to stably dissipate energy by friction or inelasticity [1][2][3][4]. In the other group, steel bars were replaced with superelastic alloy (SEA) bars [5][6][7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Feasibility of tension braces using Cu-Al-Mn superelastic alloy bars

Araki

Maekawa

Shrestha

et al. 2014

Struct. Control Health Monit.

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SUMMARY This paper investigates the feasibility of tension braces using Cu–Al–Mn superelastic alloy bars as energy dissipating and self‐centering elements for steel frames by performing 1/3 scale shaking table tests. The difficulty with conventional steel tension braces lies in pinching or significant deterioration of stiffness and strength under cyclic loading. When a steel frame with conventional tension braces is subjected to intense earthquakes, pinching may lead to a large residual drift and/or instability. To overcome the difficulty, this paper examines the effectiveness of Cu–Al–Mn superelastic alloy bars, facilitated by their large recovery strain, low material cost, and high machinability, as a partial replacement of steel bars in tension braces. In the shaking table tests, a 1/3 scaled 1‐bay, 1‐story steel frame with the present tension braces is subjected to quasi‐static cyclic loading and dynamic harmonic ground motions of 6 Hz. Both the static and dynamic test results demonstrate the effectiveness of the present braces in avoiding pinching under the ductility ratio up to 3. The dynamic test results also demonstrate the capability of the present tension braces in reducing the peak response acceleration within the base shear capacity. To study the rate dependence of the frame response, further, time‐history analyses are performed by using a SDOF model based on a uniaxial rate‐independent model, calibrated with the quasi‐static tests. A comparison of the analytical results with the dynamic test results demonstrates that the rate dependence of the frame response is negligible up to the loading frequency of 6 Hz. Copyright © 2014 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Feasibility of tension braces using Cu-Al-Mn superelastic alloy bars

Araki

Maekawa

Shrestha

et al. 2014

Struct. Control Health Monit.

View full text Add to dashboard Cite

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“…Based on the results from the research study in Phocas and Pocanschi [3], initial values of a stiffness factor k (damper to structure stiffness), k= 0.1062, in combination with a cable's diameter of dc= 20 mm, were selected. Within the suggested value areas, the dual systems can effectively dissipate a large portion of the seismic input energy in respect to typical earthquake excitations of the GreekMediterranean region, with no significant influence on the magnitude of the base shear force that would affect the input energy in a linearly proportional function.…”

Section: Influence Of the Stiffness Of The Bracing-damper Mechanismmentioning

confidence: 99%

“…The dual structural systems, based on the concept originally proposed in Phocas and Pocanschi [3], are investigated in their earthquake responses, in three different structural configurations. The kinetics of the proposed systems reveals clearly the design concept of dual systems.…”

Section: Introductionmentioning

confidence: 99%

Dual earthquake resistant frames

Sophocleous

Phocas

2009

WIT Transactions on the Built Environment

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Structural control through energy dissipation systems has been increasingly implemented internationally in recent years and has proven to be a most promising strategy for the earthquake safety of structures. In extending the "classical" approach of the capacity design for earthquake structural resistance, the integration of passive damping devices within the structure aims at energy dissipation within specific structural zones. The present paper examines an alternative control system for achieving dynamic structural adaptability, which consists of an energy dissipation device and a cable bracing mechanism with a kinetic closed circuit, working only in tension. The closed bracing mechanism does not practically affect the initial stiffness of the system, i.e. the concept relies on two completely "separate" systems: a primary for the vertical-and wind loads and a secondary for the earthquake loads. An additional feature of the bracingdamper mechanism compared to conventionally passively controlled systems is the contribution of all bracing members to the energy dissipation during a loading cycle. Three "dual systems" with different configurations of the closed bracing mechanisms and damping devices are investigated in their dynamic behaviour, in the time-history range under actual earthquakes of the GreekMediterranean region. The study provides significant response comparisons of the dual systems, in respect to the stiffness of the hysteretic dampers, its effect on the base shear force and the maximum relative displacements of the systems and to the energy dissipation behaviour of the bracing-damper mechanism.

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“…Related studies on the development of a tension-only bracing-damper mechanism in different bracings configurations have been conducted in [9,10]. The Adaptable Dual Control Structures, ADCS, developed consist of a cable bracing with closed circuit and a hysteretic damper of steel plates.…”

Section: Introductionmentioning

confidence: 99%

Cable bracing design in adaptable dual control systems

Phocas

Sophocleous

2013

WIT Transactions on the Built Environment

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Structural control through energy dissipation systems has been increasingly implemented internationally in the last years and has proven to be a most promising strategy for earthquake safety of structures. The present paper examines an alternative control system development for achieving dynamic structural adaptability. The prototype control system consists of a hysteretic energy dissipation device of triangular steel plates and a tension-only bracing with closed circuit realized through implementation of rotating discs at the braces connections. A typical configuration design of the kinetic mechanism consists of a portal-and a chevron cable bracing. Based on three representative international strong earthquake motions of differing frequency contents, parametric dynamic analyses of the SDOF system responses mainly characterized by high energy dissipation have been performed by the authors in previous studies with regard to the mechanical characteristics of the hysteretic damper, i.e. elastic stiffness and yield force, whereas the cables were modelled as frame objects with zero compression limit. In the present study the optimum controlled system is further investigated in its earthquake responses with different cable stiffness values and a pretension stress. The respective numerical nonlinear analyses conducted exemplify the earthquake performance of the bracing-damper mechanism, while a linear elastic resistance of the tension-only members is verified.

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Steel frames with bracing mechanism and hysteretic dampers

Cited by 39 publications

References 6 publications

Feasibility of tension braces using Cu-Al-Mn superelastic alloy bars

Feasibility of tension braces using Cu-Al-Mn superelastic alloy bars

Dual earthquake resistant frames

Cable bracing design in adaptable dual control systems

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