Dissipations in reinforced concrete components: Static and dynamic experimental identification strategy
TL;DR: The IDEFIX experimental campaign (French acronym for Identification of damping/dissipations in RC structural elements ) has been carried out on RC beams set up on the Azalee shaking table of the TAMARIS experimental facility operated by the French Alternative Energies and Atomic Energy Commission (CEA).
About: This article is published in Engineering Structures.The article was published on 2018-05-15. It has received 9 citations till now. The article focuses on the topics: Damping ratio.
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TL;DR: In this article, an evolving equivalent viscous damping ratio for a simply supported reinforced concrete beam is estimated for a reinforced concrete structure in the scope of a moderate seismicity context for which steel yielding is not expected.
16 citations
TL;DR: The SINAPS@ project as discussed by the authors ) is a five-year project aimed at conducting a continuous analysis of completeness and gaps in databases (for all data types, including geology, seismology, site characterization, materials), of reliability or deficiency of models available to describe physical phenomena (i.e., prediction of seismic motion, site effects, soil and structure interactions, linear and nonlinear wave propagation, material constitutive laws in the nonlinear domain for structural analysis), and of the relevance or weakness of methodologies used for seismic safety assessment).
Abstract: This contribution provides an overview of the SINAPS@ French research project and its main achievements. SINAPS@ stands for “Earthquake and Nuclear Facility: Improving and Sustaining Safety”, and it has gathered the broad research community together to propose an innovative seismic safety analysis for nuclear facilities. This five-year project was funded by the French government after the 2011 Japanese Tohoku large earthquake and associated tsunami that caused a major accident at the Fukushima Daichi nuclear power plant. Soon after this disaster, the international community involved in nuclear safety questioned the current methodologies used to define and to account for seismic loadings for nuclear facilities during the design and periodic assessment review phases. Within this framework, worldwide nuclear authorities asked nuclear licensees to perform ‘stress tests’ to estimate the capacity of their existing facilities for sustaining extreme seismic motions. As an introduction, the French nuclear regulatory framework is presented here, to emphasize the key issues and the scientific challenges. An analysis of the current French practices and the need to better assess the seismic margin of nuclear facilities contributed to the shaping of the scientific roadmap of SINAPS@. SINAPS@ was aimed at conducting a continuous analysis of completeness and gaps in databases (for all data types, including geology, seismology, site characterization, materials), of reliability or deficiency of models available to describe physical phenomena (i.e., prediction of seismic motion, site effects, soil and structure interactions, linear and nonlinear wave propagation, material constitutive laws in the nonlinear domain for structural analysis), and of the relevance or weakness of methodologies used for seismic safety assessment. This critical analysis that confronts the methods (either deterministic or probabilistic) and the available data in terms of the international state of the art systematically addresses the uncertainty issues. We present the key results achieved in SINAPS@ at each step of the full seismic analysis, with a focus on uncertainty identification, quantification, and propagation. The main lessons learned from SINAPS@ are highlighted. SINAPS@ promotes an innovative integrated approach that is consistent with Guidelines #22, as recently published by the French Nuclear Safety Authority (Guidelines ASN #22 2017), and opens the perspectives to improve current French practice.
10 citations
Cites background from "Dissipations in reinforced concrete..."
...Indeed, as revealed during these experimental campaigns, it is possible to identify an increasing damping level with the evolving damaged state of the RC sections, see for instance (Heitz et al. 2018)....
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...The Ph.D. study of T. Heitz (2017) allowed the performing of a huge experimental seismic campaign, and part of the data were studied and interpreted (Heitz et al. 2018)....
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6 citations
Cites background from "Dissipations in reinforced concrete..."
...Under this condition, the damping should account for the remaining energy dissipation which is not explicitly modeled, including the energy dissipated through cracking or internal friction between the constitutive material.(15) Considering the fact that the viscous damping mechanism is not derived from sound physical principles, the choice of the viscous damping model to cover this part of energy dissipation is quite questionable....
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Dissertation•
16 Nov 2017
TL;DR: This thesis takes place in the framework of the RSNR SINAPS@ project whose main objective is the improvement of modeling tools allowing to appreciate the effects of an earthquake from the rupture of the fault to the vibratory behavior of the structures and amenities.
Abstract: Assessment of safety margins related to a seismic risk in Civil Engineering requires the improvement of the predictive methods usually performed. The damping phenomena still remain a major source of uncertainty both at the structure and the constitutive material levels. However, the resistance of the said structure to an earthquake is strongly conditioned by its ability to store and to dissipate the energy introduced by the ground motion. Better modeling and evaluation of these effects are therefore essential for the seismic risk assessment. This thesis takes place in the framework of the RSNR SINAPS@ project whose main objective is the improvement of modeling tools allowing to appreciate the effects of an earthquake from the rupture of the fault to the vibratory behavior of the structures and amenities.
4 citations
TL;DR: The sensitivity of some engineering demand parameters is quantified and discussed as a function of the structural typology (beam-column or wall-based structures) and of the considered assessment method.
3 citations
References
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TL;DR: In this article, the necessary and sufficient conditions under which both discrete and continuous damped linear dynamic systems possess classical normal modes were determined for both continuous and discrete linear systems, respectively.
Abstract: The purpose of this paper is to determine necessary and sufficient conditions under which both discrete and continuous damped linear dynamic systems possess classical normal modes.
884 citations
TL;DR: In this paper, the damping forces generated by such a matrix can become unrealistically large compared to the restoring forces, resulting in an analysis being unconservative, and a remedy to these problems is proposed in which bounds are imposed on the dampings forces.
Abstract: Rayleigh damping is commonly used to provide a source of energy dissipation in analyses of structures responding to dynamic loads such as earthquake ground motions In a finite element model, the Rayleigh damping matrix consists of a mass-proportional part and a stiffness-proportional part; the latter typically uses the initial linear stiffness matrix of the structure Under certain conditions, for example, a non-linear analysis with softening non-linearity, the damping forces generated by such a matrix can become unrealistically large compared to the restoring forces, resulting in an analysis being unconservative Potential problems are demonstrated in this paper through a series of examples A remedy to these problems is proposed in which bounds are imposed on the damping forces Copyright © 2005 John Wiley & Sons, Ltd
288 citations
TL;DR: In this paper, a method is presented to obtain a non-proportional (non-viscous) viscous damping matrix from complex modes and complex natural frequencies.
261 citations
TL;DR: In this paper, the authors describe damping ratio characteristics of steel-framed buildings and reinforced concrete (RC/SRC) buildings based on analyses of the database, including effects of several building factors.
Abstract: Full-scale data on damping of buildings in Japan have been collected by the Damping Evaluation Committee of the Architectural Institute of Japan. Reliable data on 137 steel-framed buildings, 25 reinforced concrete (RC) buildings, 43 steel-framed reinforced concrete (SRC) buildings have been compiled in a database. Most of these data have been evaluated from vibration tests in a small amplitude region. This paper describes damping ratio characteristics of steel-framed buildings and RC/SRC buildings based on analyses of the database, including effects of several building factors. It is shown that the higher the building, the smaller the first-mode damping ratio. Furthermore, the damping ratios seem to be affected by building use: Those of hotels and apartments are generally larger than those of other buildings. However, damping ratios are more widely scattered than natural periods, because they are also affected by vibration amplitude, foundation type, and so on. Frequency and amplitude dependencies of damp...
257 citations
TL;DR: In this article, the authors presented the physical meaning of the frequency domain decomposition (FDD) method to estimate the modal parameters of a nine-storey reinforced concrete (RC) dwelling in Grenoble (France).
163 citations