Increasing the Contribution of GFRP Bars on the Compressive Strength of Concrete Columns with Circular Cross Section

Corrosion of steel in concrete elements is a major issue in concrete structures. In order to overcome this matter, Glass Fiber Reinforced Polymer (GFRP) reinforcement is being used in concrete members from almost 20 years ago. Although it has been used and developed in recent years, there are still some uncertainties for the application of FRP reinforcement, especially in concrete columns.  Most codes such as ACI, CSA, JSCE & etc. neglects the effect of these reinforcements or they do not permit them in compressive concrete elements. In this essay, it has been shown that these rebar can contribute significantly in compressive strength of concrete columns if the column confinement is provided sufficiently. In order to achieve the required confinement to reach a sharp contribution of GFRP longitudinal rebar in concrete columns, the spiral of FRP rebar with small pitches around longitudinal rebar is taken into account. This leads to higher strains of concrete which can result in a higher contribution of FRP longitudinal rebar. Foremost, equations related to the compressive strength of concrete columns considering the influence of spiral confinement will be carried out. Then, a parametric study will be performed, and the effects of pitch, concrete strength, column diameter, the quantity of longitudinal rebar and concrete cover will be investigated

Development of an elastic solution for predicting the dynamic response of beams subjected to a moving mass

In this investigation, the problem of the response of beams subjected to a moving mass has been studied. The main objective in this thesis is to provide easy and acceptable solutions for this problem. Three different methods of solution are presented. (I) The first method demonstrates the transformation of a familiar governing differential equation into a new solvable series of ordinary differential equations. (II) The second method discusses the solution of the same problem based on a new discrete element model for beams. (III) The third method is based on a finite element technique. The computer program used in this investigation is called PAFEC. The validity of the solutions is ascertained by comparison. Furthermore, the study shows that the response of beams due to a moving mass, which has often been neglected in the past, must be properly taken into account because it often differs significantly from the moving load model. Based on the cost of computations and desirable accuracy, a designer can choose the appropriate method

An Analytical Solution for Free Vibration of Elastically Restrained Timoshenko Beam on an Arbitrary Variable Winkler Foundation and Under Axial Load

Abstract Natural frequencies are important dynamic characteristics of a structure where they are required for the forced vibration analysis and solution of resonant response. Therefore, the exact solution to free vibration of elastically restrained Timoshenko beam on an arbitrary variable elastic foundation using Green Function is presented in this paper. An accurate and direct modeling technique is introduced for modeling uniform Timoshenko beam with arbitrary boundary conditions. The applied method is based on the Green Function. Thus, the effect of the translational along with rotational support flexibilities, as well as, the elastic coefficient of Winkler foundation and other parameters are assessed. Finally, some numerical examples are shown to present the efficiency and simplicity of the Green Function in the new formulation

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Abstract Natural frequencies are important dynamic characteristics of a structure where they are required for the forced vibration analysis and solution of resonant response. Therefore, the exact solution to free vibration of elastically restrained Timoshenko beam on an arbitrary variable elastic foundation using Green Function is presented in this paper. An accurate and direct modeling technique is introduced for modeling uniform Timoshenko beam with arbitrary boundary conditions. The applied method is based on the Green Function. Thus, the effect of the translational along with rotational support flexibilities, as well as, the elastic coefficient of Winkler foundation and other parameters are assessed. Finally, some numerical examples are shown to present the efficiency and simplicity of the Green Function in the new formulation

Analysis of concrete shallow funicular shells of rectangular plan

Analysis of concrete shallow funicular shells of rectangular plan with simply supported boundary conditions under static loads is performed using the Ritz method. Double Fourier series with the unknown constant coefficients are assumed for the displacement components of the shell and their unknown coefficients are determined such that the potential energy of the shell becomes minimum. The solution is presented in a simple form and is suitable for practical applications. The responses of rectangular–plan concrete shallow funicular shells including deflections, strains, internal forces, internal moments and stresses could be easily determined using the proposed semi-analytical method. The Ritz method results are verified against the finite element method results