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