Journal of Materials and Engineering Structures

305-322

Authors: Houssam KHELALFA

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 eliminate the risk of wharf caissons instability. Decent number of research and development works of the preloading process in different countries by several authors have been cited, with the aim of justifying our research and results. 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.

337-344

Authors: Tounsia BOUDINA, Ahcene SERIDI, Dalila BENAMARA

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 Boumerdès) indicate the presence of the site effects and which allows the derivation of a spectrum calculation to the studied site.

359-374

Authors: Qasim M. SHAKIR, Baneen B. ABD

In this work, an experimental study has been conducted to investigate the behavior of self-consolidating high strength reinforced concrete dapped end beams upgraded with CFRP composites. A series of 14-specimens have been tested, each of with length of 1500 mm, total depth of 400mm and width of 200mm. Two values of shear slenderness ratio (a/d) namely (1.5 and 1.0) are adopted. Two specimens have been considered as a reference beams (with full Design reinforcement), four were deficiently reinforced in either hanger or the extended disturbed zone, and the other eight beams have been upgraded with a variety of arrangements by CFRP fabric. This work aims to observe the effects of deficiently reinforced disturbed zones on the resistance and overall behavior of such elements. Also, the extent of strength recovery using CFRP sheeting. It is observed that reducing the hanger reinforcements by a half, results in a drop of capacity by (13%) regardless of values of (a/d). Furthermore, it is noticed that adopting the inclined arrangement of CFRP sheets with (450) yielded the best results if compared with other arrangements. An enhancement in failure load was about (23%) for (a/d=1.0).

383-395

Authors: Ibrahim MESSAOUDENE, Mohammed EZZIANE, Laurent MOLEZ

This experimental work studies the durability of mortars made with Portland cement composed of industrial fillers: granulated slag and marble powder. Samples of normal mortar were exposed for 12 months to sulphuric acid. The evolution of crystalline phases was analyzed by XRD and minerals were observed by SEM. Microanalysis (EDS linked to SEM) confirms their chemical composition. For a low concentration of sulphate (0.05 mol/l), the results show that the hydrates of cement (CSH, CH, ettringite) seem unaffected in the interior of the sample where the sulphur is completely absent. However in the case of attack by a high concentration (0.25 mol/l) of sulphuric acid, samples develop a dense surface gypsum deposit. The mechanism of the attack is mainly due to the expansive action of gypsum.

409-426

Authors: Djamel BASAID, Abdelbaki BENMOUNAH, Chouaib ARIBI, Abdelghani MAY

The composite materials present weakness to shocks and impact, studies are carried out in order to minimize the consequences of these defects, solutions are adopted for temporary or permanent. solutions are adopted for temporary or permanent repairs. 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. The effectiveness of these repairs is verified using the study of conventional tensile behavior. For the characterization of the damaged state and validation of the results, non-destructive NDT control is carried out on specimens developed under the same conditions as repair plates attached to the fuselage plane.

443-453

Authors: 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.