Browsing by Author "Kadri, Mohammed"

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Capacité sismique des silos à grains en béton armé seismic capacity of reinforced concrete grain silos
(2020) Benkhellat, Sonia; Seghir, Abdelghani; Kadri, Mohammed; Kada, Ouassila
Les ouvrages de stockage de matières granulaires, comme les silos en béton armé, sont des constructions industrielles particulières calculées selon des normes sismiques spécifiques en raison des multiples cas de chargements-déchargements auxquels ils sont soumis. Dans le présent travail, on s’intéresse à l’analyse de la capacité sismique de ces ouvrages en utilisant la méthode de poussée progressive (push over). Le chargement est appliqué sous forme d’accélération à la base uniformément croissante afin de prendre en compte les effets inertiels induits par la masse de la matière ensilée supposée répartie sur les parois du silo. Les résultats obtenus par une analyse d’un cas de silo de grandes dimensions ont permis d’évaluer sa capacité sismique et les éventuels dommages qu’il peut subir à différents niveaux d’accélérations sismiques
A coupling method between extended boussinesq equations and the integral equation method with application to a two-dimensional numerical wave-tank
(Elsevier, 2009) Hamidou, M.; Molin, B.; Kadri, Mohammed; Kimmoun, O.; Tahakourt, A.
Damage assessment in RC columns using the energy dissipation of ultrasonic waves
(Springer Nature, 2024) Toukal, A.; Labdaoui, R.; Kadri, Mohammed
Reinforced concrete (RC) columns, widely used in various types of structures, are prone to significant damage from cyclic loads, such as seismic events or repeated stresses, particularly in older buildings. Accurate damage assessment is crucial for ensuring safety and reliability or determining the need for reinforcement. Traditional evaluation methods often involve time-consuming invasive techniques, whereas non-destructive testing (NDT) methods provide innovative approaches to monitor and assess structural health swiftly and without causing additional damage. This paper investigated the damage assessment in reinforced concrete columns subjected to alternating cyclic loading by calculating the damage index based on ultrasonic energy dissipation. To achieve this, non-destructive tests were conducted alongside mechanical tests. Ultrasonic signals of waves passing through the material, as well as displacements at the top of the columns, were recorded for each loading cycle. The extent of damage, represented by the damage index (DI) value, was estimated using the proposed model, which is based on variations in ultrasonic signal energy. The comparison between the results obtained with the proposed model and those from other authors demonstrates the effectiveness and validity of the proposed model based on ultrasonic signal energy for damage index evaluation. Additionally, this approach facilitates the assessment of structural conditions after an earthquake and enhances structural health monitoring (SHM).
Enhancing resilience of repaired RC column using thin polypropylene fiber reinforced concrete jacketing
(Techno-Press, 2025) Labdaoui, Rachid; Toukal, Abdennour; Kadri, Mohammed
This study investigates the effectiveness of thin jacketing with polypropylene fiber-reinforced concrete for strengthening reinforced concrete (RC) columns. Full-scale specimens were retrofitted using thin jackets of polypropylene fiber- reinforced concrete, steel fiber-reinforced concrete, and plain concrete, then subjected to a constant vertical load combined with cyclic horizontal loading to simulate seismic conditions. Key performance metrics, including load-bearing capacity, ductility, energy dissipation, damage index, and cra ck propagation, were assessed and compared. The findings highlight the effectiveness of fiber-reinforced concrete thin jacketing in enhancing the seismic performance of RC columns. Notably, this method significantly improves load-bearing capacity, ductility, and energy dissipation while delaying crack formation and enhancing overall seismic resilience.
Erosion process of a core clay in earth and rockfill dams : laboratory experiments and numerical modelling
(Springer, 2021) Kadri, Mohammed; Benamar, Ahmed
Internal erosion of dam’s embankments is a complex process and considered as the main cause of hydraulic works failure. Laboratory experiments provide a potential insight into the processes involved. Particles detachment from a core of earth and rock fill dams within a crack submitted to water seepage may lead to backward erosion which gradually progresses till forming a pipe. Clay of designed core must provide a quite good resistance against erosion, which depends on material and flow characteristics. The present study reports the results from hole erosion tests (HET) aiming to assess the erodibility of a clayey soil collected from a deposit by Tipaza (Algeria) and used in the core confection of an earthen dam. For this purpose, tests were performed under successive hydraulic loads and the pressure drop was measured as close as possible to the pipe edges. Hydrodynamic parameters effect on erosion rate of tested soil was investigated and the susceptibility of tested soil to erosion was addressed. A numerical simulation of turbulent flow in hole pipe using FEM was carried out to approach the hydrodynamic process occurring inside the hole and to compute shear stress acting along the wall. Numerical values of local shear stress were matched with analytical values and used to describe the area impacted by erosion and the hole radius evolve. Numerical results showed that the usual analytical evaluation of shear stress along the hole overestimates strongly the effect of seepage on the hole wall. Attempts are also made to assess the erodibility classification of tested soil from analytical and numerical results to estimate the deviation usually affecting the interpretation of HET
Free vibration behaviour of multi-directional functionally graded imperfect plates using 3D isogeometric approach
(Techno-Press, 2022) Lahdiri, Abdelhafid; Kadri, Mohammed
In this paper the free vibration frequencies of tri-directional functionally graded materials imperfect plate is investigated for Several plate geometries with two types of porosity (even and uneven) and different type of material configuration. The effect of several parameters such as power law index and boundary conditions have been investigated. For this purpose, an efficient computational method is developed and written under Matlab environment, based on a three dimensional modeling and the isogeometric method is used for the discretization of the structure based on NURBS (Non uniform rational B-spline) basis functions. The results obtained by the present method are validated by the comparison with the results given by several authors in the literature.
Modélisation du comportement dynamique et simulation de la réponse sismique non linéaire des silos à grains en béton armé.
(2019) Benkhellat, Sonia; Seghir, Abdelghani; Kadri, Mohammed
Les silos à grains sont des ouvrages industriels particuliers utilisés pour le stockage des matières granulaires. Ces ouvrages sont calculés selon des normes sismiques spécifiques dû aux multiples cas de chargements auxquels ils sont soumis. Dans le présent travail, on s’intéresse à la modélisation du comportement dynamique et à la simulation numérique de la réponse sismique non linéaire de ces structures en effectuant des analyses dynamiques non linéaire par accélérogrammes (Time history analyses). Les parois des silos sont des voiles en béton armé dont le comportement non linéaire doit tenir compte des comportements des deux matériaux acier et béton composant leurs sections. Un modèle numérique basé sur les éléments de type coques multicouches (multilayer shell elements) est adopté pour prendre en compte ce comportement mixte. La matière granulaire stockée est modélisée par des éléments solides et par des masses équivalentes. Les résultats obtenus ont permis d’analyser la capacité du silo étudié sous un chargement sismique et d’obtenir l’évolution des contraintes et des déformations dans les aciers et dans le béton en fonction du temps.
Numerical investigation of the effects of soil-structure and granular material-structure interaction on the seismic response of a flat-bottom reinforced concrete silo
(Institute of Engineering Mechanics (IEM), 2024) Benkhellat, Sonia; Kadri, Mohammed; Seghir, Abdelghani
In this work, a numerical study of the effects of soil-structure interaction (SSI) and granular material-structure interaction (GSI) on the nonlinear response and seismic capacity of flat-bottomed storage silos is conducted. A series of incremental dynamic analyses (IDA) are performed on a case of large reinforced concrete silo using 10 seismic recordings. The IDA results are given by two average IDA capacity curves, which are represented, as well as the seismic capacity of the studied structure, with and without a consideration of the SSI while accounting for the effect of GSI. These curves are used to quantify and evaluate the damage of the studied silo by utilizing two damage indices, one based on dissipated energy and the other on displacement and dissipated energy. The cumulative energy dissipation curves obtained by the average IDA capacity curves with and without SSI are presented as a function of the base shear, and these curves allow one to obtain the two critical points and the different limit states of the structure. It is observed that the SSI and GSI significantly influence the seismic response and capacity of the studied structure, particularly at higher levels of PGA. Moreover, the effect of the SSI reduces the damage index of the studied structure by 4%.
Particle transport within water-saturated porous media : effect of pore size on retention kinetics and size selection
(Elsevier, 2013) Ikni, Tahar; Benamar, Ahmed; Kadri, Mohammed; Ahfir, Nasre-Dine; Wang, Hua-Qing
Seismic damage assessment of reinforced concrete grain silos
(World Scientific, 2021) Benkhellat, Sonia; Kada, Ouassila; Seghir, Abdelghani; Kadri, Mohammed
This paper deals with seismic performance and damage assessment of concrete grain silos. An existing large silo is taken as a case study to conduct the numerical analyses. A global damage index based on target displacement is proposed to quantify numerically different damage states of the structure. To this aim, the classical N2 method is extended to adaptive multimodal to evaluate seismic performance of the structure for increasing pic ground acceleration levels with taking into account degradation of stiffness and modification of modal characteristics. The seismic capacity of the silo is evaluated, as an averaged curve, by conducting pushover and several incremental dynamic analyses using artificial and recorded accelerograms. The seismic demand is derived from the design spectrum of the Algerian seismic code (RPA 2003). The target displacement is determined by taking into account both the participation of the dominant modes, and the degradation of the structure’s modal characteristics. The nonlinear behavior of the structure’s walls is modeled by using nonlinear multilayered shell elements. The effect of the stored granular material is included through distributed equivalent masses. It is found that when the structure modal characteristics are updated as its stiffness is degraded, the target displacement is correctly computed. Whereas, it wrongly grows indefinitely, with increasing PGA, when constant modal characteristics of the intact structure are assumed, as usually done. The proposed global damage index is compared to three existing reliable indices. It better reflects the different damage states of studied silo
Seismic response of concrete gravity dam with soil structure interaction using isogeometric approach.
(2019) Lahdiri, Abdelhafid; Kadri, Mohammed
The paper deals with the numerical analyses carried out on the Oued-Fodda concrete gravity dam under earthquake shaking with account of soil structure interaction. The seismic behavior of the dam-soil system is performed by the isogeometric approach based on the NURBS shape functions and the water mobilized by the dam is modeled with the Westergaard’s mass added approach usually applied in most of literature studies. The motion equations are solved by the direct integration method of Newmark. The results are compared with the results obtained by SAP code and other authors using the finite element method. The effect of soil structure interaction is evidenced by comparing displacements at the dam crest
Un couplage Boussinesq - equation integrale applique a l’interaction de la houle avec des obstacles bidimensionnels
(2009) Hamidou, M.; Molin, B.; Kimmoun, O.; Kadri, Mohammed; Liu, Y.
On présente ici une m´ethode de couplage entre les ´equations de Boussinesq ”´etendues”, suivant la formulation potentielle de Jamois [1], et la m´ethode d’´equation int´egrale. La mise en oeuvre est r´ealis´ee dans le cas d’un bassin `a houle bidimensionnel. Des validations sont pr´esent´ees