Accepted Papers to Appear in Future Issues

Experimental and numerical analysis of the fields of the frozen stresses in an epoxy sphere using the method of freezing mechanical cutting

Kamel TOUAHIR, Ali BILEK, Philippe BOCHER, Mustapha BELDI

The stresses induced by a mechanical contact imposed on a sphere have been studied experimentally and numerically. The technique of freezing and mechanical cutting in thin slices was used. Slices are analyzed on a polariscope using plane light and circular light. The photoelastic fringes are used to determine the principal directions of the stresses as well as the values of the stresses. A numerical simulation using the finite elements made it possible to make a comparison with the experimental results. The analysis shows a good correlation between experimental measurements and numerical simulation.
Date accepted : 2018-12-25

Durabilité des ciments Portland composés de fillers de déchets industriels dans un milieu acide
Mohammed EZZIANE, Ibrahim MESSAOUDENE, Laurent MOLEZ

Ce travail expérimental étudie la durabilité de mortiers réalisés avec un ciment Portland composé de fillers industriels : laitier granulé et poudre de marbre. Les échantillons sont conservés durant 12 mois dans l’acide sulfurique. L’évolution des phases cristallines est suivie par diffraction X et les minéraux sont observés au MEB, la microanalyse qui lui est associée permet de confirmer leur composition chimique. Les résultats montrent qu’à une concentration de 0,05M, les hydrates du ciment (CSH, CH, ettringite) ne semblent pas affectés à l’intérieur de l’échantillon, le soufre est y totalement absent. En revanche, les mortiers exposés à une forte concentration (0,25M) en acide sulfurique développent un dépôt extérieur dense de gypse. Le mécanisme de l'attaque est principalement dû à l'action expansible du gypse.
Date accepted : 2018-11-05

Protection of structures subject to seismic and mechanical vibrations using periodical networks
Amine AMRANE, Nouredine BOURAHLA, Abdelkader HASSEIN-BEY, Abedelkrim KHELIF

The concept of frequency gaps in phononic crystals is widely used in physics. The feasibility and efficiency of applying this principle in damping out seismic and mechanical induced vibrations in real scale of civil engineering constructions are presented in this article through the results obtained from numerical modeling and analysis of a concrete substratum embedding steel elements (pillars) coated in a polyvinyl chloride polymer (PVC). The first configuration having the elements fully embedded into the substrate resulted in two narrow band gaps at relatively high frequencies; and when only the metallic pillars are emerging from the substrate, the band gaps shift towards the low frequencies. The results are improved and show the existence of three band gaps at medium frequencies ranging from 80 to 200 m/s when both the pillars and the polymer are emerging from the foundation. Exploring other metal-polymer pairs of materials such as "steel-rubber", "steel-silicone"," lead-rubber" and "lead-silicone", shows that a range of band gaps has shifted again towards the lower frequencies which cover part of the seismic frequency domain. Further improvement are obtained by notching the ends of the substrate in order to widen and lower the band gaps especially for "metal-rubber" pairs. These results show the potential of using periodic networks to mitigate seismic and mechanical vibration effects on large scale structures and components.
Date accepted : 2018-12-04

Parametric study with FE model of cold-formed plain lipped C-section in shear, and combined bending and shear

Tabassum Mahzabeen RAKA, Khan Mahmud AMANAT

The study focuses on the finite element (FE) modelling of cold formed plain lipped C-section in shear, and combined bending and shear, which was developed using ANSYS. Hence, a parametric study on plain C-section was conducted to investigate the applicability of the direct strength method (DSM). In addition, DSM capacity curves were constructed to find out the limitations of DSM. It is found that the DSM equations for nominal shear capacity with tension field action (TFA) gives the capacity that is acceptable when full tension field action is developed while the nominal DSM moment capacity at local buckling outlines conservative results. However, the study also reveals that the DSM nominal shear capacity without tension field action provides lower capacity than the real peak capacity and therefore, it concludes that this method is more conservative.
Date accepted : 2019-01-02

Seismic performance of mid-rise code-conforming X-braced steel frames
Mokhtar ANSARI, Hosein Gholi POUR, Amir SAFIEY

Prolixity and complexities inherent in non-linear dynamic analysis (NDA) impels engineers to lean towards nonlinear static analysis (NSA) in practice. This paper partly explores differences and similarities in responses obtained from these two simulation techniques. The scope of study is narrowed down to ubiquitous regular code-conforming mid-rise steel X-braced frames. Different common lateral load patterns are coupled with NSA to study their interactive effects on responses. Modal nonlinear static analysis is also carried out, where deemed necessary. NDA using three different earthquake records are conducted as well, to validate NSA results. Results of nonlinear analyses are undertaken to compare provisions of seismic rehabilitation code with those of seismic design codes. Base shear, story drift, lateral displacement profile obtained for each model are independently thoroughly discussed. Eventually, some suggestions to improve design code requirements are accordingly provided, as applicable.
Date accepted : 2018-12-08

Study of Mortars Made with Natural and Artificial Pozzolans

The objective of this work is to evaluate the thermal activation potential of clay soils, particularly the clay fraction of dam mud, for the production of artificial pozzolan which can be substituted to cement in concrete and mortars applications and also to make a comparative study with the natural pozzolan available in the area of Beni Saf in considerable quantities. The research study is carried out on three mortars 10, 20 and 30% of natural pozzolan of Beni Saf and artificial pozzolan from the mud calcined at 850 ° C / 3 hours of the dredged sediments of the dams of Fergoug and Ouizert, and on a control mortar without additions for the need of comparison. Several physical, mechanical, microstructural and sustainable tests have been carried out to carry out this research study: maneuverability in the fresh state, impeded shrinkage, mechanical performance, absorption, acid attack (5% CH3COOH, 5% HNO3 and 5% H2SO4), mass loss and pH reading follow-up in the hardened state. Compressive strengths indicate that pozzolan-based mortars have the best results in particular over the long term, whereas the results of acid attack tests show that the calcined mud has a significantly greater influence than natural pozzolan.
Date accepted : 2018-12-10

Use of crushed clay brick waste as dune sand granular corrector in mortar manufacturing
Abderrahmane Ghrieb, Yacine Abadou

The purpose of this work is to use the crushed clay brick waste to make it a useful material for correcting dune sand granulometry, in order to manufacture with them mortars with satisfactory performance in terms of consistency, compactness, mechanical strength and resistance to aggressive agents. The mixtures composition method is based on the progressive substitution of dune sand with crushed waste at different weight contents; 5, 10, 15, 20 and 25%. The results obtained show that the incorporation of the used waste has a significant influence on the behavior of the mortar, in the fresh state and the hardened state. Further to this, it has also been observed that its inclusion with certain percentages makes it possible to obtain performances comparable to those of the alluvial sand-based mortar, which demonstrates its effectiveness in improving the various properties of the mortar.
Date accepted : 2019-01-15

Numerical Analysis of the Tetrapylon Roman's Triumphal Arch of Tebessa: A Case Study.
Ahmed Rouili, Mabrouk Touahmia

The Tetrapylon Roman Triumphal Arch or commonly called 'Caracalla Gate', located in Tebessa City (Northern Algeria), is considered as one of the most distinctive type of arches associated with the ancient Roman's architecture. This historical monument, erected in the 3rd century, was dedicated to the Roman Emperor Caracalla. In the 6th Century the Caracalla gate was enclosed in the Byzantine old city, built by the General Salomon. Although the monument is still standing, over time, it suffered apparent damages. The conservation and restoration of this monument is actually a major preoccupation for the concerned authorities. In this paper a 3D numerical analysis of the deformations and global stability of the gate are presented. The numerical results obtained were compared to previous site survey and measurements, and were found to be in good agreement. The results revealed that part of the monument damages and deformations occurred following the construction of the Byzantine walls. In its actual state, the monument was found sufficiently stable, and the restoration would not affect its firmness, if appropriate materials and techniques are deployed.
Date accepted : 2019-01-15

Contribution to Probabilistic Modeling of Soil Geo-mechanical Properties for Structural Reliability Analysis of Shallow Foundations
KAZI TANI Nabil, NEDJAR Djamel, TAMINE Tawfik, HAMANE Mabrouk

This present study synthesizes a numerical approach to optimize foundation systems design and underground pipes based on the combination of elasto-plastic soil behavior and probabilistic modeling of its geo-mechanical characteristics. Also, this work allows quantifying the effects of soil spatial variability on the mechanical and structural reliability of civil engineering infrastructures anchored at shallow depths in the ground. The illustrated simulations are based on simultaneous combination of the elasto-plastic soil behavior and its spatial variability, which allow to describe accurately the mechanical behavior of civil engineering infrastructures in complex environments.
Date accepted : 2019-01-20

Etude expérimentale de la réparation des structures d'aéronefs par collage des patchs à base d’époxy et fibre de verre

Djamel Basaid, Abdelbaki Benmounah, Chouaib Aribi, Abdelghani May

The composite materials present weakness to shocks and impact caused by different projectiles (Foreign Object damage, birds, lightning ....), Studies are carried out in order to minimize the consequences of these defects solutions are adopted for temporary or permanent repairs existing as procedures in a manual called SRM (manual repair structure). This experimental work carried out at the University of Boumerdes in collaboration with AIR ALGERIE airlines. This paper aims to study some cases of repair of aircraft structures. These repairs are applied to the defects present on the composite materials of the "Low Energy Impact" type aircraft structure using the Epoxy matrix composite patch method: EPOCASTA50-1, a non-diluted resin reinforced with glass of the same type as that of the aircraft fuselage. Then, the effectiveness of these repairs is verified using the study of conventional tensile behavior by applying a stress of the order of 80% of maximum stress, in relaxation mode. For the characterization of the damaged state and validation of our results we used the method of non-destructive NDT control based on ultrasound, this verification is carried out on specimens developed under the same conditions as repair plates attached to the fuselage plane.
Date accepted : 2019-01-20

Experimental study of the long-term shortening of reinforced concrete columns under maintaining concentric axial load
Ngoc Long TRAN, The Truyen TRAN, Manh Hung NGUYEN, Van Quyet TRUONG

This paper presents the results of an experimental study to measure the shortening of reinforced concrete (RC) columns under long-term maintaining concentric axial load. Long-term axial deformation due to shrinkage and creep of the concrete were recorded beside deformation due to mechanical load. Eight RC cylinder - columns (content of reinforcement 1.5% and 2%) with diameter of 150 mm and height of 600 mm were tested during the period of 600 days to determine their shortening. The experimental results showed that the long-term deformation of RC columns occurs primarily during the first year of loading. The deformation creep of concrete is much greater than the shrinkage deformation. The reinforcement content has a significant effect on the long-term deformation of concrete columns.
Date accepted : 2019-01-27

Comparison between DRF for displacement and acceleration spectra with uncertain damping for EC8
baizid benahmed, Abbas Moustafa

A damping reduction factor (DRF) is used to estimate high damping response spectra from their 5% counterpart. DRF has been studied by many researchers using mathematical relations as function of damping ratio xi and natural period T, are available in the literature which have been implemented in the seismic codes worldwide.
The damping force experienced by a building during an earthquake differs significantly from the value specified in the design process. This introduces uncertainties in the design process of buildings under earthquake loads. Accordingly, it is desirable to consider not only the effects of uncertainties in loading but also the uncertainties in the structural parameters. The aim of this work investigates the effects of uncertainties inherent on damping ratio on the use of DRF for the evaluation of high damping response spectra. The DRF values are evaluated from both acceleration and displacement response spectra. Effects of period of vibration, level of damping ratio and site class and the level of uncertainties of damping on the DRFs are evaluated and discussed. The damping uncertainties are represented by a lognormal probability distribution function and the Monte Carlo Simulation (MCS) technique is used to generate the random values of xi .
First, three sets of natural records, compatible (on average) with the EC-8 response spectra have been selected in accordance with the Europeen seismic code EC8 Afterwards, the selected records have been used to derive response spectra with uncertain dampings through response history analysis for the displacement and the acceleration responses. Finally, a comparison between these approaches was presented and important conclusions were attired on the light of the results obtained.
Date accepted : 2019-02-01

Preloading of harbor's quay walls to improve marine subsoil capacity


Preloading is an improvement technique for compressible soils, and has been applied at DjenDjen port in Jijel province, Algeria, as part of its development and expansion. In addition, this treatment to minimize the risk of quay wall instability. The objectives are to understand and apprehend the coastal soil preloading method and its application in terms of the sensitivity of the intervening factors on its achievements, and their effect on the behavior of the soil and the marine structure during and after its implementation. Furthermore, a numerical simulation of the real test of the method of treatment is carried out, by the plaxis 2D code in finite elements, also respecting the actual construction phasing of this structure, in order to compare the calculation results with in-situ measurements to validate the numerical models and to check the stability of the harbor structure. A matrix of consolidation process during pre compression is proposed.
Date accepted : 2019-03-02

Workability, compressive strength and initial surface absorption of laterized concrete
Samuel Olufemi FOLAGBADE, Opeyemi Ayodeji OSADOLA

This paper investigated the workability, compressive strength and initial surface absorption of plasticised laterized concrete at the water/cement ratios of 0.30, 0.50 and 0.70. Slump, compressive strength at 7, 14, 21 and 28 days and initial surface absorption after 10 minutes (ISA-10) at 28, 60 and 90 days were determined at the laterite contents of 0, 20, 40, 60, 80 and 100%. ISA-10 was also assessed at 28-day strengths of 20, 25 and 30 N/mm2. Results showed that superplasticiser dosage increased with increasing content of laterite and for economic dosage laterite content should be limited to 40%. At equal water/cement ratios, compressive strength reduced with increasing content of laterite and ISA-10 increased with increasing content of laterite. The results also showed a strong relationship between ISA-10 and compressive strength and that laterized concrete, when specified on the basis of strength, would have resistance to initial surface absorption comparable with that of the conventional concrete if laterite content is limited to 40%. Hence, for good workability, compressive strength and permeation resistance, laterite content of concrete should be limited to 40%.
Date accepted : 2019-03-10

The contribution of GIS in the quantification of the evolution of Skikda's coastline between 1960 and 2002 and the impact of developments.
Nedjoua CEMALI, Mohamed Tahar BENNAZZOUZ, Sihem RAMOUL

The coastline is considered as a place of great physical and socioeconomic complexity. The concentration and competition from human activities have caused damage to the environment. Coastal erosion is a natural phenomenon of the morphological evolution of coastlines. But in recent decades this phenomenon has become a very important coastal risk that threatens different types of constructions (harbor, tourist facilities, urban area…). So the analysis and monitoring of the evolution of the coastline and research on the impact of developments on the coastal environment allow to define a better management and coastal planning policy. This article présents the dynamic evolution of the coastline using geomatics tools (remote sensing and GIS). The diachronic analysis of the evolution of Skikda's coastline shows a strong morphological variability manifested by a net decline of the coastline, seriously threatening the stability of the infrastructures.
Date accepted : 2019-03-20

Investigation on the glass fiber reinforced geopolymer concrete made of M-sand
Chithambar Ganesh A, Muthukannan M

This research work investigates the effect of utilization of glass fibers in geopolymer concrete made of Manufactured sand (M-sand) over its fresh and hardened properties and understand the influence of fibers over reducing the brittleness of the matrix. Geopolymer concrete synthesized in this study is Fly ash- GGBS blend type with optimum molarity cured under heat condition. Fresh property of the fiber reinforced geopolymer concrete was accessed using compaction factor test. Mechanical properties such as compressive strength, split tensile strength, flexural strength, impact strength, ductility factor, first crack toughness, failure crack toughness and ultimate failure toughness were measured and their results are analyzed and discussed in this work. Later, SEM analysis was carried out over the optimum fiber reinforced geopolymer concrete samples to understand the bonding and the effectiveness of the fiber reinforced geopolymer concrete made of M-sand. Incorporation of glass fiber s proved to be more beneficial and yielded a hybrid concrete with increased strength properties. The performance of fiber s could be measured precisely in increasing the ductility and impact strength. Scanning Electron Microscopy (SEM) analysis showed better bonding between the fiber s and the matrix. This study unleashes an enormous scope for the practical implication of fiber reinforced geopolymer concrete as a building material.
Date accepted : 2019-04-25

Structure of the out-flows behind buildings and Influence of the geometry of the streets on the out-flows.

This paper intends to study the latest results from the research methods available with special intentions given to the architectural effects of the street valley and wind speed. Extensive research has been carried out through several research approaches to understand the effect of wadi formation on the streets and the current wind condition on the structure of the wind current. The current work is to study the structure of out- flows of buildings and the effect of street engineering on external flows. The purpose of this calculation software is to simulate the airflow of the air in the city boundary layer and to be simulated by ANSYS Fluent. The program was based on the K-ε model. To incorporate the potential of differential equations forming the mathematical model, the limited size method was used in the transcendental behavior of the unknown to divide the equations of possible equations. (3): The first case is the height-to-width ratio of the valley (h/w), the second is the width of the dome (b3/b) and the third case the ratio of the height of the valley (h3/h) to see the effect of street valley engineering and wind speed effect.
Date accepted : 2019-04-27

Estimation of compressive strength of high-strength concrete by random forest and m5p model tree approaches
Balraj SINGH, Parveen SIHAG, Anjul TOMAR, Ankush SEHGAD

High strength concrete (HSC) define as the concrete that meets a unique mixture of performance uniformity requirements that cannot be reached routinely using conventional constituents and regular mixing, placing, and curing events. The modeling of such type of concrete is very difficult. In this investigation, the performance of the random forest regression and M5P model tree were compared to estimate the 28th day compressive strength of the HSC. Total data set consists of 83 data out of which 70 % of the total dataset used to train the model and residual 30 % used to test the models. The accuracy of the models was depending upon the three performance evaluation parameters which are correlation coefficient (R), root mean square error (RMSE) and maximum absolute error (MAE). The results recommend that random forest regression is more accurate to predict the compressive strength as compare to M5P model tree. Sensitivity analysis indicates that water (W) and Silica fumes (SF) are the most valuable constituents of the HSC and compressive strength mainly depends on these constituents.
Date accepted : 2019-05-07

Effect of Chemically Modified Banana Fibers on the Mechanical Properties of Poly-Dimethyl-Siloxane-Based Composites
Yiporo Danyuo, Taiwo Zakariyyah, Nasiru Suleman, Kabiru Mustapha, Tahiru S. Azeko, Sefiu A. Bello, Miriam Abade-Abugre, John Yirijor, Victor Anyidoho, Fred McBangonluri

The study presents the mechanical properties of polymer-based composites reinforced with chemically modified banana fibers, by alkalization in different concentrations of sodium hydroxide (NaOH). The fiber weight fraction has a great effect on the mechanical properties of the composites. Stiff composites were obtained at 6 wt% fiber fractions with Young’s modulus of 254.00 ±12.70 MPa. Moreover, the yield strength was 35.70 ±1.79 MPa at 6 wt% fiber fractions. However, the ultimate tensile strength (UTS) ) and toughness of the composites were obtained at 5 wt% fiber fractions. Statistical analyses were used to ascertain the significant different on the mechanical properties of the fibers and composites. The implication of the results is then discussed for potential applications of PDMS-based composites reinforced with chemically modified banana fibers.
Date accepted : 2019-05-19

Sorption mechanism of copper ions on synthetic and natural dentine hydroxyapatites
Farida Fernane, Saliha Boudia, Ahmad B.Albadarin, Farid Aiouache

Removal of copper ions from aqueous solutions on synthetic and dentine waste hydroxyapatites (HAP) was investigated in batch sorption experiments. Kinetics of sorption followed a pseudo-first order model. Steady-state data show agreement with the Sips isotherm compared with Freundlich and Langmuir models. The higher surface area and carbonated nature of synthetic hydroxyapatite were not sufficient to reach higher sorption capacity than natural one. Ion-exchange and precipitation contributed on removal of Copper despite level ionization of hydroxyapatites. Proton and metal exchanges with copper ions contributed to process of sorption with prevalence of proton-exchange at low copper ion concentrations. High temperatures promoted the removal efficiency of Cu(II) onto the natural and synthesised hydroxyapatites. The thermodynamic parameters showed that sorption process was spontaneous, endothermic and associated entropy at the solid/solution interface increased at high temperatures.
Date accepted: 2019-06-03

Durability performance of Green Concrete Incorporating Various Wastes: A Review
Salmabanu Luhar, Ismail Luhar

The present research manuscript stands for the review on the topic of durability attribute of concretes developed by means of green conception with incorporation of a variety of solid industrial waste slag from Ground Granulated Blast Furnace, silica fume, rice husk ash, pulverised fly ash, glass powder waste as well as materials that have undergone recycling in order to know its degree of sustainability. It is highly sought-after to transform these types of waste into a precious adding up materials in place of Ordinary Portland Cement (OPC) in building-up of Green concrete with affordable cost and more essential with a little carbon footprint. How far these Green concept concretes have succeeded in context to its durability characteristic is the principal focus of this review study. There prevails an enormous demand for cost-effective construction materials for offering enough residences and infrastructure networks to get rid of the burgeoning population on the planet earth. The centre of attention is to make researcher, engineer and infrastructure related peoples, as well as construction industry au courant of absorbing the, dissipate materials and their promotion as an acceptable, sustainable and cost-effective building materials. The apposite standards of durability and still excellent researches on the sustainability of this novel Green concept concrete will encourage for espousal of gargantuan construction and infrastructures projects globally. Looking to the above facts, it can be predicted that the said Green technology bestows the impression to have dazzling potential and its approval in construction industries which establishes it as the most promising future edifice material.
Date accepted : 2019-06-03

Fracture parameters formulation for single edge notched AS4 stitched warp-knit fabric composite plate
Mostefa Lallam, Said Mamouri, Abdelkader Djebli

The three-dimensional problem of the fracture for the single edge notched tension plate (SENT) of orthotropic material is considered in this paper. The finite element solution is used to evaluate the singular and non-singular terms of the William series, i.e. Stress intensity factor (SIF) and T-stresses namely T11, T13 and T33. Based on the obtained numerical results, a fitting procedure is performed in order to propose analytical formulations giving the fracture parameters near the crack tip. The obtained results are in good agreement with the finite elements calculation and other literature results.
Date accepted : 2019-06-10

Deriving a specific response spectrum from the site of the Algiers Grand Mosque (Algeria)
Tounsia BOUDINA, Ahcene SERIDI

The estimation of the soil seismic response at the surface can be made by several experimental methods, approximate and numerical. This study consists in using numerical simulation to determine the surface response in terms of maximum acceleration and response spectrum of soil profiles located at the site of the Grand Mosque of Algiers, taking into account the soil’s non-linearity behavior, with an equivalent linear behavior (hysteresis degradation of the shear modulus G). The responses calculated on the surface that they are amplified or de-amplified compared to the excitation at the base (earthquake of May 21, 2003 in Boumerdes) indicate the presence of the site effects and which allows the derivation of a spectrum calculation to the studied site.
Date accepted : 2019-06-10

Effect of a crack emanating from notch on a composite pipe subjected to buckling
Halima CHENINE, Djamel OUINAS, Zine-Eddine BENNACEUR, Jaime Vina OLAY

New pipelines made with composite materials have to be well-designed for better mechanical performances. Recommendations for sizing stratified pipes have been proposed for different combinations of loads. In this context, our paper focus on buckling on laminated composite pipes, using numerical simulation. As a first part, we study free-defect pipes buckling for different pipe diameters, wall thicknesses and fibers orientation. In a second part, we evaluate the influence of defects (notches and crack due to notches), their parameters (size, orientation) and mechanical constraints (pipe under pressure, boundary conditions) on the structure. Results show a strong dependence of the size of the notch to the stability of the structure, amplified by the fibers orientation. Thus, for fibers oriented at an angle close to 20°, pipes manufacturing under these conditions show a particular strength of the structure. The crack length (independently on its orientation) seems to have no significant effect on the buckling factor and therefore the structure integrity, for transverse-orientated fibers and while their orientation go beyond 40°. The main variations are observed when fibers orientation is in the range from a few degrees up to 40°. Results are and discussed according the orientation of crack and fibers.
Date accepted : 2019-06-14