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The existing of openings in the structural elements of concrete may be useful in some cases and necessary at other cases. Experimental study on Reinforced Concrete (RC) beams was address in this research to examine the conduct of the opening in RC beams. The target of this study is to evaluate the impact of web elliptical openings in reinforced concrete beams experimentally. Under two-point top loading, four reinforced beams were tested, three of them with openings and one without opening. Test variable included the number of elliptical openings. Test results indicated that incase of the number of opening increased the ultimate load decreased. The ultimate load of CBEH1, CBEH2 and CBEH3 beams are decreased by 12%, 24% and 28% respectively compared with the ultimate load of CB beam.

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A three-dimensional finite element (FE) model for single-walled carbon nanotubes with armchair and zigzag shapes is proposed in this paper (SWCNTs). Nodes are positioned at the locations of carbon atoms to design the FE models. And three-dimensional elastic beam components are used to model the bonds between them. The effect of the diameter length/diameter ratio on the diameter length/diameter ratio, cross sectional aspect ratio and number of elements on the Young’s modulus of SWCNTs has been considered herein. From the conducted experiments it can be observed that, the larger tube diameter can lead to higher Young’s modulus for carbon nanotubes. Such that, maximum elastic modulus for the armchair and the zigzag models has be obtained to be 1.0285TPa and 1.0396TPa when the diameters for the armchair and the zigzag models were 2.034nm and 1.957nm respectively. Increasing the length/diameter ratio has led the Young’s modulus to be increased for armchair and zigzag models such that its values can reach 1.0451TPa and 1.0191TPa respectively. The cross sectional aspect ratio of SWCNTs showed an inversely proportional effect on the elastic modulus in this work. As a result of rising the cross sectional aspect ratio to be2, the Young's modulus for armchair and zigzag models has decreased to 0.7991TPa and 0.8873TPa, accordingly. The change in geometry has been observed to be a defect and it is in general can decrease the modulus of elasticity. The number of elements in the armchair model considered as prominent factor that increases the young’s modulus to be 1.0280TPa when the number of element is 10836. In zigzag model, the number of element has no effect on the elastic modulus since the number of nodes that exposed to the applied load is fixed in this case. The findings showed that the proposed FE model may be useful for studying carbon nanotube mechanical action in the future.

Due to the corrosion that occurs in internal steel reinforcement; many of steel reinforced concrete structure are at risk of collapse. The budget that will be developed to address this risk in terms of replacement or repair of damaged concrete structures will be very high for the owner or responsible authorities. Alternatives to bare steel have been used including stainless steel, galvanized steel, epoxy-coated steel and cathodic protection, with limited effectiveness. The characteristics of fiber reinforced polymer (FRP) bars like the high tensile strength, inability to corrode, and light weight; it has become the focus of decision-makers to use it instead of steel in internal reinforcement for future concrete structures. In this research, we have investigated flexural behavior in reinforced concrete beams with bars from bars from carbon fiber-reinforced polymer (CFRP), bars from high tensile steel (HTS), and glass fiber-reinforced polymer (GFRP) under static load. Two groups from samples were used, in the first group will show the effect of the type of reinforcement. In the second group will show the effect of the type of reinforcement with different concrete strength. It found these kinds of materials to be very is effective to deal with analysis and the proposed simulation of the material in this study are able of forecast the real behavior of reinforced concrete beam by FRP bars in terms of failure load, and load-deflection behavior.

Many models were introduced to estimate the  roundabout entry capacity from 1980s until  now. In the United States, transportation  agencies adopted three different models from  1994 until 2010. The Austroads, the UK, and  the HCM 2010 methods. In this paper, these  three methods were used to analyze the field  traffic data of Al-Quds roundabout, located  near Baqubah City, simultaneously by utilizing  a system dynamics model. The collected data  included turning movements, circulating flows,  and field calculated entry capacities whenever  possible during the observation period which  lasted for 14 consecutive hours. A comparison  is then conducted on the resulting entry capacities and their variation over time. The  results showed that the calculated capacity  according to Austroads method is the highest at all times while the UK method was always a little lower and the HCM 2010 method was  always the least on all entries. The UK method  capacity estimates were the closest to the field  measured capacities for they returned the least  RMSE on all entries. Field capacities showed some tendency towards the Austroads results  in the north and south bound entries which  carry about 66% of the total traffic. While, field capacities showed more proximity  towards the HCM capacity results in the east  and the west bound entries which carry 34% of  the total traffic.