Muhammad Abed Attiya Alfatlawi

present paper. ANSYS software was utilized to simulate the behaviour of cold-formed steel column under static load. Two groups of steel column were analyzed. The first group has box section while the other has channel section. Materials and geometric nonlinearity were adopted in this study. An experimental data were used for this reason. A reasonable agreement by means of load and axial displacement between experimental and ANSYS results was obtained. Furthermore, the effects of column length, location of opening, and stiffener location on behaviour of cold formed steel columns are investigated. It is found that, stiffeners have significant effect when they are used at ends of the column rather than they exit around the opening. Increasing length of the column clearly increases the axial displacement and slightly decreases the load capacity

the resistance to cracking and crack propagation. This work has been made to study the properties of polymer modified concrete when micro-steel fiber is incorporated at different volumetric percentages from 0.1 % to 2 %. Two mixes (1:1.5:2 and 1:2:4) have been used and modified with styrene butadiene rubber resin (SBR) and silica fume with maintaining water cement ratio at 0.45. It has been found that increasing steel fiber content in concrete has a significant influence on the increase compressive, tensile, flexural strength, modulus of elasticity and stress- strain relationship. Flexural strength increases from 4.14 MPa (for 0% steel fiber) to 11.83 MPa (for 2% steel fiber). Whereas, the modulus of elasticity is improved by about 77% (for 1:1.5:2 mixes) and 91% (for 1:2:4 mixes

Abstract The direction of bolts and its effect on the bearing capacity of double shear bolted connections has been examined in this paper. Sixteen specimens with up to four bolts have been tested under tensile load. These specimens have been sorted into two series (L, T) according to the bolt direction with applied loads The experimental results have clearly indicated that the bearing capacity of connections had been considerably affected by changing the direction of bolts. With tear-out failure, All specimens of L series showed high bearing capacity and good ductility while block shear failure was the distinguishing feature of specimens of T series.

Abstract— The present study deals with numerical analysis of reinforced (RC) simply supported beam strengthened by carbon fiber reinforced polymer (CFRP) element. The two commonly used techniques near surface mounted (NSM) and externally bonded reinforcement (EBR) are considered. For the NSM technique, the two configurations of strengthening by CFRP, rod and sheet, have been used, while Sheet type at bottom surface of beam is used for EBR technique. ANSYS V15 has been employed to achieve the present work. Also study is focused on investigation of some parameters that may affect the performance of strengthened RC beam. Parameter studied here are; effect of NSM CFRP ratio, configuration of CFRP type of reinforcement (rod or sheet), distribution of NSM CFRP rod area through beam width and the effect of simulation of epoxy grove. The results revealed that using higher ratios of CFRP results in considerable improvement in ultimate load capacity, an increment up to 180% in ultimate load capacity can be achieved with increasing the NSM rod ratio from 0.047% to 0.377%. Slight effect of using CFRP sheet instead of CFRP rod has been obtained, the range of influence was 94% - 123%. Also use different diameters of NSM CFRP rod for the same ratio of area decreases the post- cracking stiffness response with significant decrease in ultimate load capacity. The analysis yields that use various model of epoxy-groove between CFRP and concrete have little effect on the behaviour of strengthened beam.

The experimental testing thirty reinforced concrete corbels divided into four groups. Two groups of them are strengthened with horizontal while the other two groups with inclined externally bonded CFRP strips. Each groups are strengthened with one, two, three and four layers of CFRP strips. In horizontal groups form there are two technique are used one of them, the CFRP strips are cut at end face of corbel and another are extend around the face of the corbel, the same technique are adopted in the inclined groups form. The experimental program variables include location, direction, amount of CFRP strips, effect of shear span to effective depth (a/d) ratio on the behaviour of strengthened corbels. All corbels had the same dimensions and flexural reinforcement and they were without horizontal shear steel reinforcement.

A nonlinear finite element study has been conducted to evaluate the efficiency of the technique of strengthening of reinforced concrete beams under static loads. No time dependent effect (creep and shrinkage... etc.) are considered in this work. This concept is based on prestressing of CFRP sheets. In this research program, four reinforced concrete beams were tested to investigate the feasibility of such concept for flexural strengthening. One of the beams was retrofitted with non-prestressed CFRP sheet which was used as the control beam. The rest were retrofitted with prestressed CFRP sheet with three levels of prestressing. The static load was applied at instant of full prestress load application, prestress losses were ignored here.

Abstract: This paper describes a three-dimensional nonlinear finite element techniques used to successfully model reinforced concrete beam-column joint specimens subjected to non-proportional axial and shear loads. A 20-noded isoparametric brick element had been used to model the concrete. The reinforcing steel bars were idealized as axial members embedded within the brick elements. Perfect bond between the concrete and the reinforcing bars was assumed. The behaviour of concrete in compression was simulated by an elasto-plastic work hardening model followed by a perfect plastic response, which was terminated at the onset of crushing. In tension, a fixed smeared crack model had been used with a tension-stiffening model to represent the retained post-cracking tensile stresses and a shear retention model that modified the shear modulus after cracking. The nonlinear equations of equilibrium have been solved using an incremental-iterative technique operating under load control. The solution algorithms used were the standard and modified Newton-Raphson method. The numerical integration has been conducted using the 27-point Gaussian type rule. Two types of reinforced concrete beam-column joints had been analyzed and the finite element solutions were compared with the experimental data. Several parametric studies have been carried out to investigate the effect of some important finite element and material parameters on the predicted finite element results. The study included the effect of concrete compressive strength, column axial load, beam tension and compression reinforcement, and beam shear span to depth ratio.