The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Inma Rodríguez Cantalapiedra - One of the best experts on this subject based on the ideXlab platform.
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A new steel framing system for seismic protection of timber platform frame buildings. Implementation with hysteretic energy Dissipators
Earthquake Engineering & Structural Dynamics, 2014Co-Authors: F. López-almansa, Edgar Segués, Inma Rodríguez CantalapiedraAbstract:This paper describes a new seismic protection system for timber platform frame buildings, either for new construction or retrofit. The system consists in connecting the timber frame to a steel structure that includes hysteretic energy Dissipators designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might use other types of dissipative devices. The steel structure consists of four steel stacks (located at each of the four facades) and steel collectors embracing each slab; the stacks and the collectors are connected, at each floor level, through the energy Dissipators. The steel structure is self-supporting, that is, the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main load-carrying system. The timber-steel interface is designed to avoid any stress concentration in the transfer of horizontal forces and to guarantee that the yielding of the Dissipators occurs prior to any timber failure. The energy dissipation capacity of the suggested system is discussed, and an application example on a six-story timber building is presented; this case corresponds to highly demanding conditions because of the relatively large building height and weight, the high local seismicity, and the soft soil condition. This research belongs to a wider project aiming to promote the structural use of timber by improving the seismic capacity of wooden buildings; this research includes experiments and advanced numerical simulation. Copyright © 2014 John Wiley & Sons, Ltd.
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Seismic protection of timber platform frame building structures with hysteretic energy Dissipators: feasibility study
2014Co-Authors: Edgar Segués Aguasca, Francisco López Almansa, Inma Rodríguez CantalapiedraAbstract:This paper describes a feasibility study of new hysteretic energy Dissipators for seismic protection of timber platform frame buildings, either for retrofit or for new construction. The system consists in connecting the timber frame to a steel framed structure that includes the new energy Dissipators devices, designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might contain other dissipative devices. The steel structure comprises horizontal beam-like elements, vertical column like elements and chevron-like bracing members; the beam-like elements are steel belts embracing each slab of the building and the bracing members hold the energy Dissipators. The steel structure is self-supporting, i.e. the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main carrying-loads system. The timber-steel contact is even, smoothed and spread; it guarantees that the yielding of the Dissipators is prior to any timber failure. This research belongs to a wider project aiming to promote the structural and constructional use of timber in seismic regions; this research includes experiments and advanced numerical simulation aiming to derive accurate design criteria. Comparison with unprotected buildings and other earthquake-resistant solutions is in progress.
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Energy-based design of a seismic protection system of timber platform frame buildings using energy Dissipators
2014Co-Authors: Francisco López Almansa, Edgar Segués Aguasca, Inma Rodríguez CantalapiedraAbstract:This paper deals with a new seismic protection system for timber platform frame buildings, either for retrofit or for new construction. The system consists in connecting the timber frame to a steel framed structure that includes hysteretic energy Dissipators designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might contain other dissipative devices. The steel structure comprises horizontal beam-like elements, vertical column-like elements and chevron-like bracing members; the beam-like elements are steel belts embracing each slab of the building and the bracing members hold the energy Dissipators. The steel structure is self-supporting, i.e. the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main carrying-loads system. The timber-steel contact is even, smoothed and spread; it guarantees that the yielding of the Dissipators is prior to any timber failure. This research belongs to a wider project aiming to promote the structural and constructional use of timber by improving the seismic capacity of wooden buildings; this research includes experiments and advanced numerical simulation aiming to derive accurate design criteria.
F. López-almansa - One of the best experts on this subject based on the ideXlab platform.
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A new steel framing system for seismic protection of timber platform frame buildings. Implementation with hysteretic energy Dissipators
Earthquake Engineering & Structural Dynamics, 2014Co-Authors: F. López-almansa, Edgar Segués, Inma Rodríguez CantalapiedraAbstract:This paper describes a new seismic protection system for timber platform frame buildings, either for new construction or retrofit. The system consists in connecting the timber frame to a steel structure that includes hysteretic energy Dissipators designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might use other types of dissipative devices. The steel structure consists of four steel stacks (located at each of the four facades) and steel collectors embracing each slab; the stacks and the collectors are connected, at each floor level, through the energy Dissipators. The steel structure is self-supporting, that is, the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main load-carrying system. The timber-steel interface is designed to avoid any stress concentration in the transfer of horizontal forces and to guarantee that the yielding of the Dissipators occurs prior to any timber failure. The energy dissipation capacity of the suggested system is discussed, and an application example on a six-story timber building is presented; this case corresponds to highly demanding conditions because of the relatively large building height and weight, the high local seismicity, and the soft soil condition. This research belongs to a wider project aiming to promote the structural use of timber by improving the seismic capacity of wooden buildings; this research includes experiments and advanced numerical simulation. Copyright © 2014 John Wiley & Sons, Ltd.
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Experimental study of friction Dissipators for seismic protection of building structures
Earthquake Engineering and Engineering Vibration, 2011Co-Authors: F. López-almansa, S. T. Cruz, C. TaylorAbstract:This paper presents the results from unidirectional shaking table tests of two reduced scale steel models of a building frame, with one and two fl oors, respectively. These frames incorporate friction Dissipators at every fl oor. The inputs are sine-dwells and artifi cial and registered earthquakes. This study is part of a larger research project aiming to assess the seismic effi ciency of friction Dissipators by means of an integrated numerical and experimental approach. Inside this framework, the main objectives of these experiments are to: (i) collect a wide range of results to calibrate a numerical model derived within the project, (ii) clarify some of the most controversial issues about friction Dissipators (including behavior for inputs containing pulses, capacity to reduce resonance peaks, introduction of high frequencies in the response, and selfgenerated eccentricities), (iii) better understand their dynamic behavior, (iv) provide insight on the feasibility and reliability of using simple friction Dissipators for seismic protection of building structures and (v) characterize the hysteretic behavior of these devices. Most of these objectives are satisfactorily reached and relevant conclusions are stated.
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Numerical simulation of the seismic behavior of building structures equipped with friction energy Dissipators
Computers & Structures, 2006Co-Authors: S. T. Cruz, F. López-almansa, Sergio OllerAbstract:This paper presents a new algorithm to simulate the seismic response of N-story building frames incorporating friction energy Dissipators; a device per floor is considered. The frames with the Dissipators are described by 2D lumped masses models with two degrees of freedom per floor, namely the horizontal displacements of the main structure and of the Dissipators. The proposed algorithm consists of a modification of the linear acceleration method; the main innovation consists of checking at each calculation instant the sliding or sticking condition at each floor, hence, the number of ''active'' degrees of freedom changes continuously, ranging in between N (there is sticking condition at every Dissipator) and 2N (there is sliding condition at every Dissipator). Some results given by this algorithm are compared to experimental results from ad-hoc testing and to numerical results obtained with the ADINA software package. In both cases, agreement is satisfactory while the proposed method is more computationally efficient.
Ronnie Kosloff - One of the best experts on this subject based on the ideXlab platform.
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Quantum signatures in the quantum Carnot cycle
New Journal of Physics, 2020Co-Authors: Roie Dann, Ronnie KosloffAbstract:The Carnot cycle combines reversible isothermal and adiabatic strokes to obtain optimal efficiency, at the expense of a vanishing power output. Quantum Carnot-analog cycles are constructed and solved, operating irreversibly with positive power. Swift thermalization is obtained in the isotherms utilizing shortcut to equilibrium protocols and the adiabats employ frictionless unitary shortcuts. The working medium in this study is composed of a particle in a driven harmonic trap. For this system, we solve the dynamics employing a generalized canonical state. Such a description incorporates both changes in energy and coherence. This allows comparing three types of Carnot-analog cycles, Carnot-shortcut, Endo-shortcut and Endo-global. The Carnot-shortcut engine demonstrates the trade-off between power and efficiency. It posses a maximum in power, a minimum cycle time where it becomes a Dissipator and for a diverging cycle time approaches the ideal Carnot efficiency. The irreversibility of the cycle arises from non-adiabatic driving, which generates coherence. To study the role of coherence we compare the performance of the shortcut cycles, where coherence is limited to the interior of the strokes, with the Endo-global cycle where the coherence never vanishes. The Endo-global engine exhibits a quantum signature at a short cycle-time, manifested by a positive power output while the shortcut cycles become Dissipators. If energy is monitored the back action of the measurement causes dephasing and the power terminates.
Sergio Oller - One of the best experts on this subject based on the ideXlab platform.
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Numerical simulation of the seismic behavior of building structures equipped with friction energy Dissipators
Computers & Structures, 2006Co-Authors: S. T. Cruz, F. López-almansa, Sergio OllerAbstract:This paper presents a new algorithm to simulate the seismic response of N-story building frames incorporating friction energy Dissipators; a device per floor is considered. The frames with the Dissipators are described by 2D lumped masses models with two degrees of freedom per floor, namely the horizontal displacements of the main structure and of the Dissipators. The proposed algorithm consists of a modification of the linear acceleration method; the main innovation consists of checking at each calculation instant the sliding or sticking condition at each floor, hence, the number of ''active'' degrees of freedom changes continuously, ranging in between N (there is sticking condition at every Dissipator) and 2N (there is sliding condition at every Dissipator). Some results given by this algorithm are compared to experimental results from ad-hoc testing and to numerical results obtained with the ADINA software package. In both cases, agreement is satisfactory while the proposed method is more computationally efficient.
Roie Dann - One of the best experts on this subject based on the ideXlab platform.
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Quantum signatures in the quantum Carnot cycle
New Journal of Physics, 2020Co-Authors: Roie Dann, Ronnie KosloffAbstract:The Carnot cycle combines reversible isothermal and adiabatic strokes to obtain optimal efficiency, at the expense of a vanishing power output. Quantum Carnot-analog cycles are constructed and solved, operating irreversibly with positive power. Swift thermalization is obtained in the isotherms utilizing shortcut to equilibrium protocols and the adiabats employ frictionless unitary shortcuts. The working medium in this study is composed of a particle in a driven harmonic trap. For this system, we solve the dynamics employing a generalized canonical state. Such a description incorporates both changes in energy and coherence. This allows comparing three types of Carnot-analog cycles, Carnot-shortcut, Endo-shortcut and Endo-global. The Carnot-shortcut engine demonstrates the trade-off between power and efficiency. It posses a maximum in power, a minimum cycle time where it becomes a Dissipator and for a diverging cycle time approaches the ideal Carnot efficiency. The irreversibility of the cycle arises from non-adiabatic driving, which generates coherence. To study the role of coherence we compare the performance of the shortcut cycles, where coherence is limited to the interior of the strokes, with the Endo-global cycle where the coherence never vanishes. The Endo-global engine exhibits a quantum signature at a short cycle-time, manifested by a positive power output while the shortcut cycles become Dissipators. If energy is monitored the back action of the measurement causes dephasing and the power terminates.