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Design and construction of efficient and economic Reinforced Concrete (R.C.) Hyperbolic Cooling Towers have driven the engineers toward the design of tall and thin-shell towers which have considerable high slenderness aspect ratio. Consequently, the shell of R.C. Cooling Towers with relative high slenderness aspect ratio is extremely prone to buckling instability due to wind loading. To increase the structural stability or buckling safety factor, one economic approach is to design and construct stiffening rings for the R.C. Hyperbolic Cooling Towers. Despite the research previously performed to determine the effect of stiffening rings on the buckling behavior of the R.C. Hyperbolic Cooling Towers, information resulting in maximum buckling stability is absent considering the optimized utilization of the quantity and dimension as well as the location of this type of stiffeners. In this paper, not only the effect of the stiffening rings on the buckling stability of the R.C. Cooling Tower is studied but also the optimized location,quantity and dimension of the stiffening rings are carried out for a sample RC Cooling Tower. The dimensions of the selected sample cooling tower are in average typical dimensions which are used in the current practice. In this study, finite element (F. E.) analyses has been carried out to define the buckling modes and resistance of this tower due to wind loading for different number of stiffening ring configurations. Based on the conducted buckling analysis, the optimized number, location and dimension of the stiffening rings that maximizes the tower.s buckling stability are defined and the methodology to achieve this information is discussed in this paper.

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This paper presents a simple solution based on the limit equilibrium of sliding soil wedge of reinforced backfill subjected to the horizontal acceleration in the framework of the pseudo-static method. In particular, contrary to most studies on the reinforced retaining wall, the solution proposed in this study, takes into account the effect of the uniform surcharge on the reinforced backfill soil and of its distance from the face of the wall. The results are investigated in dimensionless form of the maximum reinforcement required strength (Kmax), the dimension of the sliding wedge (Lc/H), and the factor of safety (FS). Compared to the reinforced backfill without surcharge, the presence of surcharge over the reinforced backfill and of its distance from the top of the backfill have significant effects on the stability of the system. For a fixed surcharge, a minimum distance of surcharge exists for which the presence of the surcharge does not affect the solution and the failure mechanism is that corresponding to the case of system with no surcharge. A detailed design example is included to illustrate usage of proposed procedures. Comparisons of the present results with available results show a favorable agreement.

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The paper present the results of various experimental and numerical studies on slopes, small scale physical modeling of slope under surcharge load were performed in loose sand environment. Digital images were captured during the incremental loading from side of model simultaneously. The Particle Image Velocimetry (PIV) and 3D numerical model was applied to investigate the slope under surcharge loading and some of the other important factors that control the performance of piles are investigated. The factors of safety and location of critical failure surfaces of reinforced and unreinforced slopes obtained and compared for various slopes. For homogenous slope, it is found for stabilized slope with piles, the 3D failure surface shape in front of piles is triangle, unlike its conical shape in laterally loaded piles. The paper also studies numerically the effect of soft bound effect, soil properties, pile spacing, pile position and surcharge distance effects on stabilized and none stabilized slopes. The results indicate that the depth of soft soil layer from ground surface and its angles with horizontal direction has importance effect on optimum location of stabilized pile. Studies on pile space effects shows with increasing pile space, arching phenomenon didn’t developed and partial pressure of supported portion transferred to un supported soil portion and the potential failure volume of the slope becomes large.