Dépouillements

Investigations into the benefits of base isolation for non-symmetric rigid blocks / A. Contento in Earthquake engineering structural dynamics, Vol. 38 N° 7 (Juin 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 849-866 Titre : Investigations into the benefits of base isolation for non-symmetric rigid blocks Type de document : texte imprimé Auteurs : A. Contento, Auteur ; A. Di Egidio, Auteur Article en page(s) : pp. 849-866 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Base  isolation;  Non-symmetric  rigid  block;  Security  stops  ;  Eccentricity  ;Impulse  ;  Seismic  excitation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper the influence of base isolation on the behaviour of a work of art has been analysed. To make things more realistic, the work of art has been modelled with a non-symmetrical rigid body, sitting on a base that is connected to a visco-elastic device, which represents the passive control system. To prevent the breaking of the isolation device, security stops have been introduced to limit the displacement of the oscillating base to a maximum safety value. All analyses have been carried out comparing the behaviour of the non-isolated and the isolated non-symmetric rigid body subject to impulsive and seismic excitations. The analysis is particularly focused on the effects of the eccentricity of the rigid body and on the presence of the security stops. Generally, base isolation improves the behaviour of the system while the presence of an eccentricity makes the performance of the system worse with respect to the symmetric rigid body. Moreover the security stops, although they preserve the isolator devices, cause a worsening in the performance of the systems. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121510546/abstract [article] Investigations into the benefits of base isolation for non-symmetric rigid blocks [texte imprimé] / A. Contento, Auteur ; A. Di Egidio, Auteur . - pp. 849-866. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 849-866 Mots-clés : Base  isolation;  Non-symmetric  rigid  block;  Security  stops  ;  Eccentricity  ;Impulse  ;  Seismic  excitation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper the influence of base isolation on the behaviour of a work of art has been analysed. To make things more realistic, the work of art has been modelled with a non-symmetrical rigid body, sitting on a base that is connected to a visco-elastic device, which represents the passive control system. To prevent the breaking of the isolation device, security stops have been introduced to limit the displacement of the oscillating base to a maximum safety value. All analyses have been carried out comparing the behaviour of the non-isolated and the isolated non-symmetric rigid body subject to impulsive and seismic excitations. The analysis is particularly focused on the effects of the eccentricity of the rigid body and on the presence of the security stops. Generally, base isolation improves the behaviour of the system while the presence of an eccentricity makes the performance of the system worse with respect to the symmetric rigid body. Moreover the security stops, although they preserve the isolator devices, cause a worsening in the performance of the systems. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121510546/abstract

Dimensional analysis of the earthquake-induced pounding between adjacent structures / Dimitrakopoulos, Elias in Earthquake engineering structural dynamics, Vol. 38 N° 7 (Juin 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 867-886 Titre : Dimensional analysis of the earthquake-induced pounding between adjacent structures Type de document : texte imprimé Auteurs : Dimitrakopoulos, Elias, Auteur ; Nicos Makris, Auteur ; Kappos, Andreas J., Auteur Article en page(s) : pp. 867-886 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Pounding;  unilateral  contact;  Dimensional  analysis;  Earthquake  engineering;  Pounding  of  adjacent  structures Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper the dynamic response of two and three pounding oscillators subjected to pulse-type excitations is revisited with dimensional analysis. Using Buckingham's -theorem the number of variables that govern the response of the system is reduced by three. When the response is presented in the dimensionless -terms remarkable order emerges. It is shown that regardless of the acceleration level and duration of the pulse all response spectra become self-similar and follow a single master curve. This is true despite the realization of finite duration contacts with increasing durations as the excitation level increases. All physically realizable contacts (impacts, continuous contacts, and detachments) are captured via a linear complementarity approach. The study confirms the existence of three spectral regions. The response of the most flexible among the two oscillators amplifies in the low range of the frequency spectrum (flexible structures); whereas, the response of the most stiff among the two oscillators amplifies at the upper range of the frequency spectrum (stiff structures). Most importantly, the study shows that pounding structures such as colliding buildings or interacting bridge segments may be most vulnerable for excitations with frequencies very different from their natural eigenfrequencies. Finally, by applying the concept of intermediate asymptotics, the study unveils that the dimensionless response of two pounding oscillators follows a scaling law with respect to the mass ratio, or in mathematical terms, that the response exhibits an incomplete self-similarity or self-similarity of the second kind with respect to the mass ratio. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121517591/abstract [article] Dimensional analysis of the earthquake-induced pounding between adjacent structures [texte imprimé] / Dimitrakopoulos, Elias, Auteur ; Nicos Makris, Auteur ; Kappos, Andreas J., Auteur . - pp. 867-886. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 867-886 Mots-clés : Pounding;  unilateral  contact;  Dimensional  analysis;  Earthquake  engineering;  Pounding  of  adjacent  structures Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper the dynamic response of two and three pounding oscillators subjected to pulse-type excitations is revisited with dimensional analysis. Using Buckingham's -theorem the number of variables that govern the response of the system is reduced by three. When the response is presented in the dimensionless -terms remarkable order emerges. It is shown that regardless of the acceleration level and duration of the pulse all response spectra become self-similar and follow a single master curve. This is true despite the realization of finite duration contacts with increasing durations as the excitation level increases. All physically realizable contacts (impacts, continuous contacts, and detachments) are captured via a linear complementarity approach. The study confirms the existence of three spectral regions. The response of the most flexible among the two oscillators amplifies in the low range of the frequency spectrum (flexible structures); whereas, the response of the most stiff among the two oscillators amplifies at the upper range of the frequency spectrum (stiff structures). Most importantly, the study shows that pounding structures such as colliding buildings or interacting bridge segments may be most vulnerable for excitations with frequencies very different from their natural eigenfrequencies. Finally, by applying the concept of intermediate asymptotics, the study unveils that the dimensionless response of two pounding oscillators follows a scaling law with respect to the mass ratio, or in mathematical terms, that the response exhibits an incomplete self-similarity or self-similarity of the second kind with respect to the mass ratio. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121517591/abstract

Effect of cumulative seismic damage and corrosion on the life-cycle cost of reinforced concrete bridges / R. Kumar in Earthquake engineering structural dynamics, Vol. 38 N° 7 (Juin 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 887-905 Titre : Effect of cumulative seismic damage and corrosion on the life-cycle cost of reinforced concrete bridges Type de document : texte imprimé Auteurs : R. Kumar, Auteur ; P. Gardoni, Auteur ; M. Sanchez-Silva, Auteur Article en page(s) : pp. 887-905 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Life-cycle  cost;  Cumulative  seismic  damage;  Low-cycle  fatigue  ;  Reinforced  concrete  bridges;  Monte-Carlo  simulation;  Corrosion Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Bridge design should take into account not only safety and functionality, but also the cost effectiveness of investments throughout a bridge life-cycle. This paper presents a probabilistic approach to compute the life-cycle cost (LCC) of corroding reinforced concrete (RC) bridges in earthquake-prone regions. The approach is developed by combining cumulative seismic damage and damage associated with corrosion due to environmental conditions. Cumulative seismic damage is obtained from a low-cycle fatigue analysis. Chloride-induced corrosion of steel reinforcement is computed based on Fick's second law of diffusion. The proposed methodology accounts for the uncertainties in the ground motion parameters, the distance from the source, the seismic demand on the bridge, and the corrosion initiation time. The statistics of the accumulated damage and the cost of repairs throughout the bridge life-cycle are obtained by Monte-Carlo simulation. As an illustration of the proposed approach, the effects of design parameters on the LCC of an example RC bridge are studied. The results are valuable in better estimating the condition of existing bridges and, therefore, can help to schedule inspection and maintenance programs. In addition, by taking into consideration the two deterioration processes over a bridge life-cycle, it is possible to estimate the optimal design parameters by minimizing, for example, the expected cost throughout the life of the structure. A comparison between the effects of the two deterioration processes shows that, in seismic regions, the cumulative seismic damage affects the reliability of bridges over time more than the corrosion even for corrosive environments. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121520102/abstract [article] Effect of cumulative seismic damage and corrosion on the life-cycle cost of reinforced concrete bridges [texte imprimé] / R. Kumar, Auteur ; P. Gardoni, Auteur ; M. Sanchez-Silva, Auteur . - pp. 887-905. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 887-905 Mots-clés : Life-cycle  cost;  Cumulative  seismic  damage;  Low-cycle  fatigue  ;  Reinforced  concrete  bridges;  Monte-Carlo  simulation;  Corrosion Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Bridge design should take into account not only safety and functionality, but also the cost effectiveness of investments throughout a bridge life-cycle. This paper presents a probabilistic approach to compute the life-cycle cost (LCC) of corroding reinforced concrete (RC) bridges in earthquake-prone regions. The approach is developed by combining cumulative seismic damage and damage associated with corrosion due to environmental conditions. Cumulative seismic damage is obtained from a low-cycle fatigue analysis. Chloride-induced corrosion of steel reinforcement is computed based on Fick's second law of diffusion. The proposed methodology accounts for the uncertainties in the ground motion parameters, the distance from the source, the seismic demand on the bridge, and the corrosion initiation time. The statistics of the accumulated damage and the cost of repairs throughout the bridge life-cycle are obtained by Monte-Carlo simulation. As an illustration of the proposed approach, the effects of design parameters on the LCC of an example RC bridge are studied. The results are valuable in better estimating the condition of existing bridges and, therefore, can help to schedule inspection and maintenance programs. In addition, by taking into consideration the two deterioration processes over a bridge life-cycle, it is possible to estimate the optimal design parameters by minimizing, for example, the expected cost throughout the life of the structure. A comparison between the effects of the two deterioration processes shows that, in seismic regions, the cumulative seismic damage affects the reliability of bridges over time more than the corrosion even for corrosive environments. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121520102/abstract

Hysteretic energy dissipation capacity and the cyclic to monotonic drift ratio for rectangular RC columns in flexure / Poljanek, Karmen in Earthquake engineering structural dynamics, Vol. 38 N° 7 (Juin 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 907-928 Titre : Hysteretic energy dissipation capacity and the cyclic to monotonic drift ratio for rectangular RC columns in flexure Type de document : texte imprimé Auteurs : Poljanek, Karmen, Auteur ; Iztok Perus, Auteur ; Peter Fajfar, Auteur Article en page(s) : pp. 907-928 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Reinforced  concrete  column;  Energy  dissipation  capacity;  Deformation  capacity;  Cumulative  damage;  Ultimate  drift;  Non-parametric  empirical  method Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Predictions of energy dissipation capacity and of the deterioration of deformation capacity due to cumulative damage have been made by means of a non-parametric empirical approach, called the conditional average estimator method, using empirical data on rectangular reinforced concrete columns that failed in flexure. Five input parameters were used: axial load index, index related to confinement, shear span index, concrete compressive strength, and longitudinal reinforcement index. The energy capacity was expressed in three different normalized forms and the deterioration of deformation capacity was defined as the ratio of the cyclic to the monotonic ultimate drift. The longitudinal reinforcement index, the index related to confinement, and the axial load index are the most influential input parameters in the case of energy capacity, whereas the latter two indices exhibit the most significant influence in the case of the drift ratio. Energy capacity decreases with an increasing axial load index, whereas it increases with increasing longitudinal reinforcement and with better confinement. In the case of the shear span index, the trend is more complex. Normal concrete has a higher energy dissipation capacity than high-strength concrete. Similar trends are observed for the drift ratio, with the exception of the influence of the axial load index, where the trend is opposite. The dispersion of the results is high. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121535934/abstract [article] Hysteretic energy dissipation capacity and the cyclic to monotonic drift ratio for rectangular RC columns in flexure [texte imprimé] / Poljanek, Karmen, Auteur ; Iztok Perus, Auteur ; Peter Fajfar, Auteur . - pp. 907-928. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 907-928 Mots-clés : Reinforced  concrete  column;  Energy  dissipation  capacity;  Deformation  capacity;  Cumulative  damage;  Ultimate  drift;  Non-parametric  empirical  method Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Predictions of energy dissipation capacity and of the deterioration of deformation capacity due to cumulative damage have been made by means of a non-parametric empirical approach, called the conditional average estimator method, using empirical data on rectangular reinforced concrete columns that failed in flexure. Five input parameters were used: axial load index, index related to confinement, shear span index, concrete compressive strength, and longitudinal reinforcement index. The energy capacity was expressed in three different normalized forms and the deterioration of deformation capacity was defined as the ratio of the cyclic to the monotonic ultimate drift. The longitudinal reinforcement index, the index related to confinement, and the axial load index are the most influential input parameters in the case of energy capacity, whereas the latter two indices exhibit the most significant influence in the case of the drift ratio. Energy capacity decreases with an increasing axial load index, whereas it increases with increasing longitudinal reinforcement and with better confinement. In the case of the shear span index, the trend is more complex. Normal concrete has a higher energy dissipation capacity than high-strength concrete. Similar trends are observed for the drift ratio, with the exception of the influence of the axial load index, where the trend is opposite. The dispersion of the results is high. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121535934/abstract

Procedure to predict the storey where plastic drift dominates in two-storey building under strong ground motion / Yo Hibino in Earthquake engineering structural dynamics, Vol. 38 N° 7 (Juin 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 929-939 Titre : Procedure to predict the storey where plastic drift dominates in two-storey building under strong ground motion Type de document : texte imprimé Auteurs : Yo Hibino, Auteur ; Toshikatsu Ichinose, Auteur ; J. L. Domingues Costa, Auteur Article en page(s) : pp. 929-939 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Seismic  response;  Storey  collapse;  Plastic  drift;  Rigid-plastic  model;  Elasto-plastic  model Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A procedure is presented to predict the storey where plastic drift dominates in two-storey buildings under strong ground motion. The procedure utilizes the yield strength and the mass of each storey as well as the peak ground acceleration. The procedure is based on two different assumptions: (1) the seismic force distribution is of inverted triangular form and (2) the rigid-plastic model represents the system. The first and the second assumptions, respectively, lead to lower and upper estimates of the base shear coefficient under which the drift of the first storey exceeds that of the second storey. The efficiency of the procedure is verified by dynamic response analyses using elasto-plastic model. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121535915/abstract [article] Procedure to predict the storey where plastic drift dominates in two-storey building under strong ground motion [texte imprimé] / Yo Hibino, Auteur ; Toshikatsu Ichinose, Auteur ; J. L. Domingues Costa, Auteur . - pp. 929-939. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 929-939 Mots-clés : Seismic  response;  Storey  collapse;  Plastic  drift;  Rigid-plastic  model;  Elasto-plastic  model Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : A procedure is presented to predict the storey where plastic drift dominates in two-storey buildings under strong ground motion. The procedure utilizes the yield strength and the mass of each storey as well as the peak ground acceleration. The procedure is based on two different assumptions: (1) the seismic force distribution is of inverted triangular form and (2) the rigid-plastic model represents the system. The first and the second assumptions, respectively, lead to lower and upper estimates of the base shear coefficient under which the drift of the first storey exceeds that of the second storey. The efficiency of the procedure is verified by dynamic response analyses using elasto-plastic model. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121535915/abstract

A new approximation for spectral velocity ordinates at short periods / Vinay K. Gupta in Earthquake engineering structural dynamics, Vol. 38 N° 7 (Juin 2009) 

Public ISBD [article]  in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 941-949 Titre : A new approximation for spectral velocity ordinates at short periods Type de document : texte imprimé Auteurs : Vinay K. Gupta, Auteur Article en page(s) : pp. 941-949 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Response  spectrum  method;  Spectral  velocity;  Pseudo  spectral  velocity Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Response spectrum methods in earthquake-resistant design sometimes require information on the spectral velocity (SV) for a given single-degree-of-freedom oscillator and specified seismic hazard. SV has been conventionally approximated as pseudo spectral velocity (PSV) in the case of lightly damped structures that are not too flexible. This study shows that the PSV approximation may lead to large overestimation errors when the structure is stiffer to the ground motion and the ground motion is a long-period motion. It is also shown that a new approximation requiring the use of peak ground acceleration of the motion may significantly reduce these errors. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121539135/abstract [article] A new approximation for spectral velocity ordinates at short periods [texte imprimé] / Vinay K. Gupta, Auteur . - pp. 941-949. Génie Civil Langues : Anglais (eng) in Earthquake engineering structural dynamics > Vol. 38 N° 7 (Juin 2009) . - pp. 941-949 Mots-clés : Response  spectrum  method;  Spectral  velocity;  Pseudo  spectral  velocity Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Response spectrum methods in earthquake-resistant design sometimes require information on the spectral velocity (SV) for a given single-degree-of-freedom oscillator and specified seismic hazard. SV has been conventionally approximated as pseudo spectral velocity (PSV) in the case of lightly damped structures that are not too flexible. This study shows that the PSV approximation may lead to large overestimation errors when the structure is stiffer to the ground motion and the ground motion is a long-period motion. It is also shown that a new approximation requiring the use of peak ground acceleration of the motion may significantly reduce these errors. ISSN : 0098-8847 En ligne : http://www3.interscience.wiley.com/journal/121539135/abstract

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