Researches available in literature interrelating neural networks to civil engineering design problems, especially for beep beams, are very rare. Therefore, an optimization algorithm is developed and verified in this study and coded using MATLAB functions to determine the optimum cost design of reinforced concrete deep beams. ACI 318-14 code method is used benefiting from iterative particle swarm optimization technique due to its efficiency and reliability. Minimizing total cost is used as the objective function in terms of four decision variables. Self-adaptive penalty function technique is used to handle constraints for each of the 300 randomly selected particles, and in each of the 50 total iterations followed for each one of four suggested deep beam design case studies. Performing all iterations is used as a stopping criteria for the developed algorithm. Comparative studies are made to show the effect of concrete compressive strength, live load scheme, and length of deep beam, on the optimum total cost and the corresponding decision variables. Results presented in the form of graphs and tables show that the loading condition has a significant effect on the total cost of deep beams. The cost increase is accompanied by deep beam length increase, height increase, longitudinal reinforcement area increase and vertical shear reinforcement area decrease. The calculated optimum cost is noticed for beam DB1, which is 1255 US$, with 1.29 m beam height, 0.01445 m 2 vertical shear reinforcement, 0.00914 m 2 horizontal shear reinforcement and 0.00238 m 2 main longitudinal reinforcement. The results show a relatively less difference in total cost between all the four beams at 4 m length compared to 8 m length. Also, a relatively mild increase in total cost is happened for beams DB3 and DB4 as the height increases, especially above 1.7 m height. As the main longitudinal reinforcement increases, cost of DB4 is affected more significantly than others, and as the vertical shear reinforcement increases, DB4 curve shows a relatively low degradation in cost.
Many researchers emphasize the effectiveness of steel fiber to replace the reinforcing bar in the reinforced concrete structural elements. The fiber of different types, sizes and geometries have been added to the concrete mix with a pozzolanic material to produce Ultra-High Strength Concrete (UHSC), which has excellent properties, high strength, and durability. This paper is a lab work and theoretical study consisting of casting and testing. Twenty-one simply supported RC beams to examine the beam's behavior and the shear capacity with the full or partial depth of UHSC with or without steel fibers (UHSSFRC) for replacing the reinforcing bars. The beams were divided into five groups. Preliminary experiments tests were conducted and carried out to study hardened properties of concrete such as (compressive strength, splitting tensile strength, modulus of rupture and modulus of elasticity). The selected finite element program (ANSYS) was applied to model all tested beams. It was observed that the performance of the finite element representation gives and shows good agreement with the lab work results. The test consists of failure load, deflection, cracks and failure mode. The experimental laboratory work results showed that for (1% steel fiber with reinforcement ratio ρ=0.0105 full UHSC layer) was able to give the same shear capacity for beam with (reinforcement ratio ρ=0.0157 regular concrete), while for (2% steel fiber half UHSC layer and reinforcement ratio ρ=0.0105) was able to give the same ultimate shear loads of beam with (reinforcement ratio ρ=0.0157 normal concrete). This research reveals that the hybrid layer and steel fiber effects were able to substitute for a higher reinforcement ratio with the same shear capacity.
There are different methods to minimize the evolution of heat in concrete. Since the cement is the main component that generates heat, the first procedure may be to reduce its quantities by replacing cement with fine materials that do not release heat during its reaction. This paper studies the influence of different additives (fly ash, silica fume, and metakaolin) to the concrete mixture with different ratios of (0, 5, 10, 15, 20, 25, 30%) by weight of cement, with different parameters study, were presented, including impact of additives on (compressive strength, alkalinity, heat of hydration with fixed w/c ratio of 0.35, initial setting time, final setting time and impact of w/c ratio on heat of hydration with three w/c ratio of (0.3, 0.35 and 0.4)). The water cementations materials ratio was kept steady at (0.35). The heat of hydration measurement was carried out under isothermal constrain(25±0.1C°). Thermocouples were utilized to evaluate the heat of hydration of concrete by stating time from 0 to 24 hours and measured by a thermoelectric device. Concrete cubes with dimensions 100×100×100 mm for compressive strength test were used and examined at the time of 28 days, using different mix proportions resulted from different percentages of cement additives, to perform the compressive strength test. The results revealed that the Portland cement heat of hydration is retarded in the presence of additives. The decrease in pH of the concrete mix before casting and molding affects the early hydration and strength but improves the later age concrete properties.
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