Abir Jendoubi - Academia.edu (original) (raw)
Papers by Abir Jendoubi
Mathematics, May 5, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The great risk associated with some structures subjected to earthquakes has created the need of r... more The great risk associated with some structures subjected to earthquakes has created the need of rigorous dynamic analysis that takes into account soil-structure interaction. A key step of this analysis consists of estimating the dynamic response of the foundations by calculating their impedance functions (i.e. dynamic stiffness K and dashpots C). Of course, one must starts by distinguishing the various types of pylons and foundations. This report consists of three different parts. Firstly, all aspects of the considered problem are exposed. Also, an original bibliographical study about the state of knowledge on the soil-structure interaction is presented; particularly calculation of the impedance functions while explaining the various concepts treated in this work. Secondly, the used code and some theoretical concepts of modeling are indicated. This part contains essentially numerical validation and some applications in order to evaluate the displacement functions of strip footings. Three typical cases are considered. For each case, the adopted mechanical characteristics correspond to a type of soil.The development of these applications allows studying the effect of the variation of the shear velocity versus the depth on the values of the real and imaginary parts of the displacement functions. Finally, impedances are applied to a tower under a transient wind loading to study their effect on the dynamic response of the structure and consequently on the behaviour of the transmission lines
Geotechnical Earthquake Engineering and Soil Dynamics IV, 2008
International Journal of Geotechnical Engineering, 2011
... Extensive Abir Jendoubi,1 Mourad Karray,2* and Frédéric Légeron3 ... When the purpose of inve... more ... Extensive Abir Jendoubi,1 Mourad Karray,2* and Frédéric Légeron3 ... When the purpose of investiga-tion concerns mainly the state of density of granular deposits, it is useful to normalize Vs for a constant mean effective stress σʹm, in order to eliminate the depth effect. ...
In traditional transmission line design, the structures and the foundations are separated. The st... more In traditional transmission line design, the structures and the foundations are separated. The structures are designed assuming fixity at foundation, and the foundation reactions found in this analysis are used to design the foundation itself. Criteria on maximum displacement at top of the foundation complete the design of foundations and this displacement is often used to design structures with a foundation settlement loading case. Very few studies have tried to combine the structural and foundation behaviour in a "system" approach considering the soil-structure interaction (SSI) in the case of transmission towers. This is one of the main objectives of this thesis. In the first part, the behaviour of the foundation is supposed to be linear, the soil is replaced by dynamic frequency dependent and complex impedances obtained from numerical simulations with FLAC software. The behaviour of a simplified structure and a latticed transmission tower modeled with ADINA software is...
Almost any type of structural system may be subjected to one form or another of dynamic loading d... more Almost any type of structural system may be subjected to one form or another of dynamic loading during its lifetime. In particular, transmission towers are subjected to important dynamic loads such as wind. To account for wind load, a rigorous study tacking into account soil structure interaction can be performed. A key step of this study consists of estimating the dynamic response of the foundations by calculating their complex impedance functions (i.e. dynamic stiffness K and damping C) or the displacement functions (inverse of impedance functions). The purpose of this work is to evaluate the displacement functions of strip footings on the surface of some homogeneous soil in which the shear velocity increases as a function of the effective overburden stress. Three typical cases are considered. For each case, the adopted mechanical characteristics correspond to a type of soil. In order to study their effect, the obtained impedances are applied to a simplified model of transmission ...
Electrical Transmission and Substation Structures 2012, 2012
Transmission lines (TL) towers are traditionally analyzed assuming fixed base. However, this assu... more Transmission lines (TL) towers are traditionally analyzed assuming fixed base. However, this assumption is questionable as foundation is not rigid in most cases. In other fields, such as seismic engineering, it has been reported in the past that the foundation stiffness and damping affects the structural behavior while in interaction with the structure specifically under dynamic loads. In this paper, the soil-structure interaction (SSI) effect on transmission line (TL) behavior is studied. The soil is replaced by foundation impedance, a set of frequency dependent spring and dashpot. For this purpose, a parametric study on a simplified case is presented for two types of dynamic loads: wind load and impulse load supposed to represent the effect of the shock wake following the breakage of a conductor of ground wire. To complement this parametric study, a real case is used in the analysis. The behaviour of the foundation is determined with software FLAC with its foundation impedance. Two types of soil are used in the analysis: (i) cohesive soil; (ii) granular soil. The paper confirms that foundations can modify structural behaviour significantly.
Computers, Materials & Continua
As inferred from earthquake engineering literature, considering soil structure interaction (SSI) ... more As inferred from earthquake engineering literature, considering soil structure interaction (SSI) effects is important in evaluating the response of transmission line towers (TLT) to dynamic loads such as impulse loads. The proposed study investigates the dynamic effects of SSI on TLT behavior. Linear and non-linear models are studied. In the linear model, the soil is represented by complex impedances, dependent of dynamic frequency, determined from numerical simulations. The nonlinear model considers the soil non-linear behavior in its material constitutive law and foundation uplift in a non-linear time history analysis. The simplified structure behavior of a typical lattice transmission tower is assessed. The analysis of frequency and time domain are followed through varying soil stiffness and damping values. Three different shock durations are investigated. The soil-structure system with equivalent dynamic properties is determined. The behaviors achieved utilizing a rigid and a flexible base for the structures is compared to estimate the impact of taking SSI into account in the calculation. The current mainstream approach in structural engineering, emphasizing the importance of the SSI effect, is illustrated using an example where the SSI effect could be detrimental to the structure. Furthermore, the non-linear analysis results are analyzed to show the linear approach's limitations in the event of grand deformations.
Mathematics, May 5, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The great risk associated with some structures subjected to earthquakes has created the need of r... more The great risk associated with some structures subjected to earthquakes has created the need of rigorous dynamic analysis that takes into account soil-structure interaction. A key step of this analysis consists of estimating the dynamic response of the foundations by calculating their impedance functions (i.e. dynamic stiffness K and dashpots C). Of course, one must starts by distinguishing the various types of pylons and foundations. This report consists of three different parts. Firstly, all aspects of the considered problem are exposed. Also, an original bibliographical study about the state of knowledge on the soil-structure interaction is presented; particularly calculation of the impedance functions while explaining the various concepts treated in this work. Secondly, the used code and some theoretical concepts of modeling are indicated. This part contains essentially numerical validation and some applications in order to evaluate the displacement functions of strip footings. Three typical cases are considered. For each case, the adopted mechanical characteristics correspond to a type of soil.The development of these applications allows studying the effect of the variation of the shear velocity versus the depth on the values of the real and imaginary parts of the displacement functions. Finally, impedances are applied to a tower under a transient wind loading to study their effect on the dynamic response of the structure and consequently on the behaviour of the transmission lines
Geotechnical Earthquake Engineering and Soil Dynamics IV, 2008
International Journal of Geotechnical Engineering, 2011
... Extensive Abir Jendoubi,1 Mourad Karray,2* and Frédéric Légeron3 ... When the purpose of inve... more ... Extensive Abir Jendoubi,1 Mourad Karray,2* and Frédéric Légeron3 ... When the purpose of investiga-tion concerns mainly the state of density of granular deposits, it is useful to normalize Vs for a constant mean effective stress σʹm, in order to eliminate the depth effect. ...
In traditional transmission line design, the structures and the foundations are separated. The st... more In traditional transmission line design, the structures and the foundations are separated. The structures are designed assuming fixity at foundation, and the foundation reactions found in this analysis are used to design the foundation itself. Criteria on maximum displacement at top of the foundation complete the design of foundations and this displacement is often used to design structures with a foundation settlement loading case. Very few studies have tried to combine the structural and foundation behaviour in a "system" approach considering the soil-structure interaction (SSI) in the case of transmission towers. This is one of the main objectives of this thesis. In the first part, the behaviour of the foundation is supposed to be linear, the soil is replaced by dynamic frequency dependent and complex impedances obtained from numerical simulations with FLAC software. The behaviour of a simplified structure and a latticed transmission tower modeled with ADINA software is...
Almost any type of structural system may be subjected to one form or another of dynamic loading d... more Almost any type of structural system may be subjected to one form or another of dynamic loading during its lifetime. In particular, transmission towers are subjected to important dynamic loads such as wind. To account for wind load, a rigorous study tacking into account soil structure interaction can be performed. A key step of this study consists of estimating the dynamic response of the foundations by calculating their complex impedance functions (i.e. dynamic stiffness K and damping C) or the displacement functions (inverse of impedance functions). The purpose of this work is to evaluate the displacement functions of strip footings on the surface of some homogeneous soil in which the shear velocity increases as a function of the effective overburden stress. Three typical cases are considered. For each case, the adopted mechanical characteristics correspond to a type of soil. In order to study their effect, the obtained impedances are applied to a simplified model of transmission ...
Electrical Transmission and Substation Structures 2012, 2012
Transmission lines (TL) towers are traditionally analyzed assuming fixed base. However, this assu... more Transmission lines (TL) towers are traditionally analyzed assuming fixed base. However, this assumption is questionable as foundation is not rigid in most cases. In other fields, such as seismic engineering, it has been reported in the past that the foundation stiffness and damping affects the structural behavior while in interaction with the structure specifically under dynamic loads. In this paper, the soil-structure interaction (SSI) effect on transmission line (TL) behavior is studied. The soil is replaced by foundation impedance, a set of frequency dependent spring and dashpot. For this purpose, a parametric study on a simplified case is presented for two types of dynamic loads: wind load and impulse load supposed to represent the effect of the shock wake following the breakage of a conductor of ground wire. To complement this parametric study, a real case is used in the analysis. The behaviour of the foundation is determined with software FLAC with its foundation impedance. Two types of soil are used in the analysis: (i) cohesive soil; (ii) granular soil. The paper confirms that foundations can modify structural behaviour significantly.
Computers, Materials & Continua
As inferred from earthquake engineering literature, considering soil structure interaction (SSI) ... more As inferred from earthquake engineering literature, considering soil structure interaction (SSI) effects is important in evaluating the response of transmission line towers (TLT) to dynamic loads such as impulse loads. The proposed study investigates the dynamic effects of SSI on TLT behavior. Linear and non-linear models are studied. In the linear model, the soil is represented by complex impedances, dependent of dynamic frequency, determined from numerical simulations. The nonlinear model considers the soil non-linear behavior in its material constitutive law and foundation uplift in a non-linear time history analysis. The simplified structure behavior of a typical lattice transmission tower is assessed. The analysis of frequency and time domain are followed through varying soil stiffness and damping values. Three different shock durations are investigated. The soil-structure system with equivalent dynamic properties is determined. The behaviors achieved utilizing a rigid and a flexible base for the structures is compared to estimate the impact of taking SSI into account in the calculation. The current mainstream approach in structural engineering, emphasizing the importance of the SSI effect, is illustrated using an example where the SSI effect could be detrimental to the structure. Furthermore, the non-linear analysis results are analyzed to show the linear approach's limitations in the event of grand deformations.