Journal of Materials and Engineering Structures

111-122

Authors: Florian Ion T. Petrescu, Relly Victoria Petrescu, MirMilad Mirsayar

Mechanical systems in motion type parallel structures are solid, fast and accurate. Between mobile systems parallel the best known and used system is that of a Stewart platforms, as being and the oldest system, quickly, solid and accurate. The paper presents a few main elements of the Stewart platforms. In the case where a motto element consists of a structure composed of two elements in a relative movement from the point of view of the train of propulsion and especially in the dynamic calculations, it is more convenient to represent the motto element as a single moving item. The paper presents an exact, original analytical geometry method for determining the kinematic and dynamic parameters of a parallel mobile structure. Compared with other methods already known, the presented method has the great advantage of being an exact analytical method of calculation and not one iterative-approximately.

137-151

Authors: K. Senthil, S. Rupali, Navjit Kaur

The numerical investigations has been carried out on reinforced concrete structures against blast loading to demonstrate the accuracy and effectiveness of the finite element based numerical models. The size of building was considered 3 ×3 × 3 m and whereas the size of beam and column was 0.3 m, arbitrary. The thickness of roof slab was 120 mm, whereas the reinforced concrete wall on all four sides was 0.2 m. The simulations were carried out through finite element code ABAQUS/CAE. The inelastic behavior of concrete has been incorporated through concrete damage plasticity model and the model includes compressive and tensile behavior. The elastic and plastic behavior of steel reinforcement bar has been incorporated using Johnson-cook model includes the effect of state of stress, temperature and strain rate. The simulations were carried out against varying standoff distance, mass of TNT, locations of blast origin and thickness of roof slab to examine the resistance of building. The response of structural elements were studied in light of deflection, impulsive velocity, von-Mises stresses, compression and tension damage of concrete. The results indicate that the standoff distance has great influence on the survivability of reinforced concrete slab and wall.

163-172

Authors: Hafida Marouf, Abdelaziz Semcha, Noureddine Mahmoudi, Nasreddine Bouhamou, Mahfoud Benzerzour, Walid Maherzi

The siltation as a natural phenomenon threatens the performance of harbors by reducing their docking volume compared to dams in terms of water storage, as well as their life span. An alarming rate of siltation is noted in the various basins requires an urgent cleaning operations. In a context of valorization of the sludge resulted from the dredging operations of the basins of the Oran’s port and those of the Bouhanifia’s dam which are located in Western Algeria, it is a question of studying possibilities which are offered by the use of these vases in the design of bricks building. The followed methodology is based on a physicochemical and mineralogical characterization of the two vases to reveal the one closest to the standards recommended for the manufacture of the baked brick. After analyzing sediments dredged in the port of Oran, it turned out that there is a dominance of sandy sediments, which are not recoverable in the areas of bricks we have targeted. Sustainability tests were performed on several sludge dam samples at different temperatures and percentages of water. The results gave a satisfaction in mechanical strength and durability for a firing temperature of 850 ° C and a percentage of water of 20%.

185-205

Authors: Praveen Kannam, Venkateswara Rao Sarella, Rathish Kumar Pancharathi

Of all the different kinds of failures in concrete, shear failure is a sudden and brittle and occurs abruptly without any prior warning. To avoid these types of failures in concrete, beams are traditionally reinforced with stirrups at closer spacing based on design. An experimental study was carried out to study the shear behavior of steel fiber reinforced self-compacting concrete (SCC) beams with recycled concrete aggregate (RCA) as a complete replacement of both natural coarse and fine aggregate. The experimental program consists of 24 beams of which 12 beams were cast with natural aggregate and remaining 12 beams were cast using recycled aggregates as a complete replacement of natural aggregates. Due to the use of recycled concrete aggregates as coarse and fine aggregates, the compressive strength reduced by 7.8% and 8% for 30 and 70 MPa Concrete. The ultimate shear strength reduced by 14% and 12% due to use of recycled concrete aggregates for SCC30 and SCC70 beams respectively. The investigation indicates that the ultimate load and ultimate shear strength decreases as the spacing of stirrups increased. It was observed from the experimental results that addition of steel fibers enhanced the mechanical properties of both natural aggregate based self-compacting concrete (NASCC) and recycled aggregate based self-compacting concrete (RASCC). Also due to the addition of steel fibers the performance of SCC beams has improved. The shear strength obtained experimentally was compared with the existing models in the literature and the correlation was found to be satisfactory

15-22

Authors: Rasheed Abdulwahab, Tunde Monsuru Akinleye, Hussein Sahid Taiye

Concrete is a versatile construction material comprising of cement, aggregates, water and occasionally admixture. It is very good in compression and weak in tension. To complement for the deficiency in the tensile zone; cracks, reinforcements (steel, fibre, etc.) have been found suitable. A good example of fibre is polypropylene. A concrete grade (M20) was batched and synthetic fibre (polypropylene) was used. Two categories of concrete specimens; with and without propylene fibre. The fibre was introduced in varying percentages (0.2%, 0.4%, and 0.6%) by weight of concrete. The compressive strength of concrete containing 0.4% polypropylene fibre at 28 days has the highest value of 32.22N/mm2 as compared to 30.22N/mm2, 30.49N/mm2 and 30.39N/mm2 for 0%, 0.2%, and 0.6% respectively. The splitting tensile strength at 7 days increases from 6.176 N/mm2 to 8.386 N/mm2 as the percentage of fibre increases from 0% to 0.4%.

33-45

Authors: Bachir Bouderba, Abdelrahmane Bekaddour Benyamina

The abrupt change in the properties of composite materials across the interface between different materials can cause strong inter-laminar stresses leading to delineation, cracking and other damage mechanisms. To remedy these defects, functional gradient materials (FGM), in which the properties of materials vary constantly, have been proposed. The purpose of this paper is to analyze the thermomechanical bending behavior of ceramic / metal thick plates (FGM). This work presents a model employing a new transverse shear function. The numerical results obtained by the present analysis are presented and compared with those available in the literature. It can be concluded that this theory is effective and simple for static analysis of FGM plates in thermal environments.

57-72

Authors: Taghreed Kh. Mohammad Ali

In this paper, the modulus of elasticity of lightweight concrete contains polyethylene terephthalate (PET) as fine, coarse aggregate and fiber was estimated by using experimental data from different literatures. The ratios of PET fiber range from 0.5% -1.5%. The modulus of elasticity increased by 8% for 0.5% PET fiber, and decreased by 45% when the concrete contains 1.5% PET fiber. The replacement of the fine or the coarse aggregate by using PET varies between 2.0% - 100%, and this caused decreasing the modulus of elasticity within range 1%-79%. This decreasing effected by shape and size of PET particles, strength of concrete, using of fly ash or silica fume, type of curing and ratio of aggregate to cement. More than 160 data sets, obtained by many investigators using various materials, have been collected and analyzed statistically to introduce the new formula of calculating the modulus of elasticity of concrete contained PET. The compressive strengths of the considered concretes range from 8.1 to 54 MPa. The modulus of elasticity of collected data range from 5.9 to 49 GPa. As a result, a practical equation, which is taken into consideration the ratio of PET as an aggregate or fiber, is proposed.

81-93

Authors: Souhila Benkaci, Dehbia Abir, Aziz Oumellal, Boualem Remini

The objective of this present work is to produce a synthetic distribution map of sensitivity degrees to erosion on the level of the high and middle Cheliff basin, by using the superposition model of cards “model builder” on ArcMapTM. The latter is exposed to a serious problem of soil degradation causes siltation of the majority of the dams distributed on his whole. Indeed, four classes of erosion vulnerability have been distinguished (weak, average, strong and very strong) where the strongly vulnerable areas cover the most part of the basin. The map produced provides an excellent decision-making tool for managers, in order to better target their preventive intervention strategies.

181-192

Authors: Santosh Gurjar, Jignesh. A. Amin

The assessment of wind loads on structure is generally carried out using existing codes/standards. The specifications of these codes are based on wind tunnel experiment performed on an isolated building. However, the buildings seldom exist in isolated condition. Neighbouring building may either increase or decrease the wind loads on principal building, this effect is known as interference effect. In this paper interference effect between two buildings is studied through numerical simulation using ANSYS CFX. Total drag force and interference factors for the principal building is calculated in the presence of interfering building having height ratio of 0.5, 0.75,1, 1.25, and 1.5. The results show that the upstream interfering buildings cause certain shielding effect by decreasing the mean wind load on the downstream principal building. However an amplification effect is also observed for certain location of the interfering building on upstream side. For buildings of the same cross-section, the interference factor (IF) decreases with the increase of the height of interfering building, indicating increase in the shielding effects. However the shielding effect on principal building is found to be significant when the heights of interfering buildings range from 0.75 to 1.5 of the height of the principal building. The along-wind force of the downstream principal building reduced to zero when the upstream interference building of height ratio more than one was two to three times the building breadth away from the principal building.

211-224

Authors: Mohamed Rida Seba, Said Kebdani, Ahmed Sahli, Sara Sahli

This article has been retracted at the request of the Editors-in-Chief, according to the Publication Ethics Policy and Publication Malpractice Statement. Please see : http://revue.ummto.dz/index.php/JMES/about/editorialPolicies#custom-2 This note is published, 25 June 2020

235-244

Authors: Mostefa Lecheheb, Rachid Lassoued

In this article, we study the dynamic behavior of the rail under inclined loads. The rail is modeled as a curved beam under lateral loads. When a train enters a curve, two sources lead to these lateral forces that have rarely been studied by previous researchers: the forces of action of the train result from the forces of the drawbar (due to centrifugal forces) and forces that develop due to the dynamic interaction of the vehicle and the rail. The rail is modeled as an infinite beam according to the Euler-Bernoulli theory. The use of a curved elementary section, allows to establish the solicitations that act the beam, and to write the differential equation of the system. The use of the residue theorem allows determining the Green function associated with the differential equation governing the vibration behavior of the rail system of the free beam.

259-267

Authors: Karthikeyan Loganathan, Mena I Souliman

The surface temperature of pavements is a critical attribute during pavement design. Surface temperature must be measured at locations of interest based on time-consuming field tests. The key idea of this study is to develop a temperature profile model to predict the surface temperature of flexible and rigid pavements based on weather parameters. Determination of surface temperature with traditional techniques and sensors are replaced by a newly developed method. The method includes the development of a regression model to predict the average annual surface temperature based on weather parameters such as ambient air temperature, relative humidity, wind speed, and precipitation. Detailed information about temperature and other parameters are extracted from the Federal Highway Administration's (FHWA) Long Term Pavement Performance (LTPP) online database. The study was conducted on 61 pavement sections in the state of Alabama for a 10-year period. The developed model would predict the average annual surface temperature based on the known weather parameters. The predicted surface temperature model for asphalt pavements was very reliable and can be utilized while designing a pavement. The study was also conducted on seven rigid pavement sections in Alabama to predict their surface temperature, in which a successful model was developed. The outcome of this study would help the transportation agencies by saving time and effort invested in expensive field tests to measure the surface temperature of pavements.

121-138

Authors: Houssam Khelalfa

A case study about the adoption of the dynamic compaction technique with high energy in a sandy hydraulic fill is presented. The feasibility of this technique to ensure the stability of the caisson workshop and to minimize the risk of liquefaction during manufacture. This Article is interested to establish diagnostic of dynamic compaction test, basing on the results of SPT tests and quality control as well as the details of work of compaction and the properties of filling materials. A theory of soil response to a high-energy impact during dynamic compaction is proposed.

155-167

Authors: Bouzid Haytham, Kassoul Amar

The ductility of reinforced concrete beams is very important, because it is the property that allows structures to dissipate energy under seismic loading, consequently, the brittle fractures of reinforced concrete structures can avoided. In the modern construction of reinforced concrete structures, the high-strength concrete (HSC) is widely used because of its benefits provided, such as the mechanical and durable properties. But the increasing of the concrete strength can negatively influence the ductility of reinforced beam sections, for this reason, the study of the local ductility of high-strength concrete beams is required. This paper present a numerical parametric study about the influence of different parameters on the curvature ductility of high strength concrete beams as the concrete strength, the yield strength of steel and the ratio of tension and compression reinforcements. In the end, a formula to predict the curvature ductility of HSC beams is proposed. This formula is compared with the Eurocode 2 numerical results and other numerical and experimental results.

79-86

Authors: O.A. Oyelaran, O. Balogun, A.O. Ambali, J.K. Abidoye

Skin processing produces large volumes of wastes, much of which are not utilized but disposed in the landfill. This study explored the possibility of producing briquettes from tannery waste that could be used for heating purposes for cottage factories and domestic cooking. Wastes studied are buffing dust, chrome shavings, fleshing, and hair. The briquette properties tested were moisture content, volatile matter, ash content, fixed carbon content, calorific value, compressive strength, density and durability. The moisture content of the raw materials ranged between 2.04 and 8.37% while the moisture content of the produced briquettes after 19 days of drying ranges between 1.17 and 4.13%. The volatile matter also decreases while the ash content increases after briquetting. The fixed carbon content ranges 73.79 and 93.23%. The heating values of the briquettes also showed a great increased after briquetting of between 19.82 and 21.86 MJ/kg. The compressive strength ranges between 0.17 and 0.21 kN/cm2, the durability ranges between 97.83 and 99.54%. The maximum densities of the briquettes also meet the required specifications of minimum value of 600 kg/m3. The briquettes produced also possess good qualities that make tannery solid waste a materials for production of briquettes for heating and in cottage industries

99-109

Authors: Hocine Hammoum, Akli Yahiaoui, Bachir Achour

In our previous study (Part 1); by using the graphic of Bergeron, we have drawn the relationships which allow calculating flows and pressures at the valve and the reservoir, considering that pressure losses are negligible. Now, we assume in this second contribution that these pressure losses are concentrated downstream of the pipe, just at the entry of the valve. The study will focus on water hammer-induced by a slow closing of the valve. A practical example will be presented at the end of this work in order to illustrate the exposed method.