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Ananth Ramaswamy - One of the best experts on this subject based on the ideXlab platform.
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flexural strength predictions of steel fiber reinforced high strength concrete in fully partially Prestressed Beam specimens
Cement & Concrete Composites, 2004Co-Authors: Sk Padmarajaiah, Ananth RamaswamyAbstract:Abstract This study presents results from an experimental program for eight fully Prestressed Beams and seven partially Prestressed Beams made with high strength fiber-reinforced concrete (plain concrete strength of 65 MPa). These studies mainly attempted to determine the influence of trough-shaped steel fibers in altering the flexural strength at first crack and ultimate, the load–deflection and moment–curvature characteristics, ductility and energy absorption capacity of the Beams. The magnitude of the prestress, volume fraction of the fibers ranging from 0% to 1.5% and the location of fibers were the variables in the test program. Analytical models to determine the load–deflection and moment–curvature relationships as a function of the fiber volume fraction have been formulated. Empirical relationships for the ultimate strength, first crack load level, load versus deflection and moment versus curvature as a function of fiber content have been proposed by making use of force equilibrium and compatibility considerations. A primary finding emerging from the experimental program was that the placement of fibers over a partial depth in the tensile side of the Prestressed flexural structural members provided equivalent flexural capacity as in a Beam having the same amount of fiber over the full cross-section. In large scale precast concrete applications it is expected that this would be economical and lead to considerable cost saving in the design without sacrificing on the desired structural performance. The analytical models proposed in this study predicts the test results closely.
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Flexural strength predictions of steel fiber reinforced high-strength concrete in fully/partially Prestressed Beam specimens
Cement and Concrete Composites, 2004Co-Authors: Sk Padmarajaiah, Ananth RamaswamyAbstract:Abstract This study presents results from an experimental program for eight fully Prestressed Beams and seven partially Prestressed Beams made with high strength fiber-reinforced concrete (plain concrete strength of 65 MPa). These studies mainly attempted to determine the influence of trough-shaped steel fibers in altering the flexural strength at first crack and ultimate, the load–deflection and moment–curvature characteristics, ductility and energy absorption capacity of the Beams. The magnitude of the prestress, volume fraction of the fibers ranging from 0% to 1.5% and the location of fibers were the variables in the test program. Analytical models to determine the load–deflection and moment–curvature relationships as a function of the fiber volume fraction have been formulated. Empirical relationships for the ultimate strength, first crack load level, load versus deflection and moment versus curvature as a function of fiber content have been proposed by making use of force equilibrium and compatibility considerations. A primary finding emerging from the experimental program was that the placement of fibers over a partial depth in the tensile side of the Prestressed flexural structural members provided equivalent flexural capacity as in a Beam having the same amount of fiber over the full cross-section. In large scale precast concrete applications it is expected that this would be economical and lead to considerable cost saving in the design without sacrificing on the desired structural performance. The analytical models proposed in this study predicts the test results closely.
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CRACK-WIDTH PREDICTION FOR HIGH-STRENGTH CONCRETE FULLY AND PARTIALLY Prestressed Beam SPECIMENS CONTAINING STEEL FIBERS
ACI Structural Journal, 2001Co-Authors: Sk Padmarajaiah, Ananth RamaswamyAbstract:This paper describes an experimental and analytical comparison of crack widths in eight fully and seven partially Prestressed high-strength concrete Beam specimens containing fibers(plain concrete strength 65 MPa). The variables considered in the experimental program were the magnitude of prestress, the volume fraction of fiber ranging from 0 to 1.5%, and the location of the fibers. The analytical model proposed in this study to compute the crack width includes the effect of fiber content expressed in terms of its volume fraction and aspect ratio, magnitude of the longitudinal steel strain, and the interfacial bond stress between the concrete and steel (prestressing wires, deformed bar, and fibers). It has been found that the analytical model is able to predict the crack width satisfactorily, when compared with the measured crack width, for each of the 15 Beams tested in this study, from the cracking stage up to the stage just prior to failure.
Sk Padmarajaiah - One of the best experts on this subject based on the ideXlab platform.
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flexural strength predictions of steel fiber reinforced high strength concrete in fully partially Prestressed Beam specimens
Cement & Concrete Composites, 2004Co-Authors: Sk Padmarajaiah, Ananth RamaswamyAbstract:Abstract This study presents results from an experimental program for eight fully Prestressed Beams and seven partially Prestressed Beams made with high strength fiber-reinforced concrete (plain concrete strength of 65 MPa). These studies mainly attempted to determine the influence of trough-shaped steel fibers in altering the flexural strength at first crack and ultimate, the load–deflection and moment–curvature characteristics, ductility and energy absorption capacity of the Beams. The magnitude of the prestress, volume fraction of the fibers ranging from 0% to 1.5% and the location of fibers were the variables in the test program. Analytical models to determine the load–deflection and moment–curvature relationships as a function of the fiber volume fraction have been formulated. Empirical relationships for the ultimate strength, first crack load level, load versus deflection and moment versus curvature as a function of fiber content have been proposed by making use of force equilibrium and compatibility considerations. A primary finding emerging from the experimental program was that the placement of fibers over a partial depth in the tensile side of the Prestressed flexural structural members provided equivalent flexural capacity as in a Beam having the same amount of fiber over the full cross-section. In large scale precast concrete applications it is expected that this would be economical and lead to considerable cost saving in the design without sacrificing on the desired structural performance. The analytical models proposed in this study predicts the test results closely.
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Flexural strength predictions of steel fiber reinforced high-strength concrete in fully/partially Prestressed Beam specimens
Cement and Concrete Composites, 2004Co-Authors: Sk Padmarajaiah, Ananth RamaswamyAbstract:Abstract This study presents results from an experimental program for eight fully Prestressed Beams and seven partially Prestressed Beams made with high strength fiber-reinforced concrete (plain concrete strength of 65 MPa). These studies mainly attempted to determine the influence of trough-shaped steel fibers in altering the flexural strength at first crack and ultimate, the load–deflection and moment–curvature characteristics, ductility and energy absorption capacity of the Beams. The magnitude of the prestress, volume fraction of the fibers ranging from 0% to 1.5% and the location of fibers were the variables in the test program. Analytical models to determine the load–deflection and moment–curvature relationships as a function of the fiber volume fraction have been formulated. Empirical relationships for the ultimate strength, first crack load level, load versus deflection and moment versus curvature as a function of fiber content have been proposed by making use of force equilibrium and compatibility considerations. A primary finding emerging from the experimental program was that the placement of fibers over a partial depth in the tensile side of the Prestressed flexural structural members provided equivalent flexural capacity as in a Beam having the same amount of fiber over the full cross-section. In large scale precast concrete applications it is expected that this would be economical and lead to considerable cost saving in the design without sacrificing on the desired structural performance. The analytical models proposed in this study predicts the test results closely.
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CRACK-WIDTH PREDICTION FOR HIGH-STRENGTH CONCRETE FULLY AND PARTIALLY Prestressed Beam SPECIMENS CONTAINING STEEL FIBERS
ACI Structural Journal, 2001Co-Authors: Sk Padmarajaiah, Ananth RamaswamyAbstract:This paper describes an experimental and analytical comparison of crack widths in eight fully and seven partially Prestressed high-strength concrete Beam specimens containing fibers(plain concrete strength 65 MPa). The variables considered in the experimental program were the magnitude of prestress, the volume fraction of fiber ranging from 0 to 1.5%, and the location of the fibers. The analytical model proposed in this study to compute the crack width includes the effect of fiber content expressed in terms of its volume fraction and aspect ratio, magnitude of the longitudinal steel strain, and the interfacial bond stress between the concrete and steel (prestressing wires, deformed bar, and fibers). It has been found that the analytical model is able to predict the crack width satisfactorily, when compared with the measured crack width, for each of the 15 Beams tested in this study, from the cracking stage up to the stage just prior to failure.
Nguyen Thi Huong - One of the best experts on this subject based on the ideXlab platform.
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Transverse vibrations of Prestressed continuous Beams on rigid supports under the action of moving bodies
Archive of Applied Mechanics, 2009Co-Authors: Nguyen Khang, Nguyen Phong Dien, Nguyen Thi HuongAbstract:The main objective of the paper is to investigate the dynamic response of the Prestressed Beams on rigid supports to moving concentrated loads. The governing equation of the transverse vibration of a Prestressed continuous Beam under the ununiformly distributed load is analytically formulated, taking into account the effect of the prestressing. The forced transverse vibration of the Beam under the action of a large number of moving bodies has been investigated by using the method of substructures. In addition, the reaction forces at every rigid supports can be determined from the obtained differential equations. A comparison between the numerical results for the Prestressed and the non-Prestressed Beam is presented to show the influence of the prestressing and the moving velocity of the bodies on the dynamic response of the Beam. The calculating results are also examined and validated by experimental measurements at a large ferroconcrete bridge in Vietnam.
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ON THE COMPRESSION SOFTENING EFFECT OF Prestressed BeamS
Vietnam Journal of Mechanics, 2006Co-Authors: Nguyen Van Khang, Nguyen Phong Dien, Nguyen Thi HuongAbstract:The main objective of the present paper is to study the transverse vibration of the Prestressed Beams. The differential equation of the transverse vibration of the Euler-Bernoulli Beam is developed , in which the initial axial strain in every cross section of the Beam is taken into account, so that the initial normal stress is not equal to zero. We have proposed some formulae to determine the natural frequencies of the Prestressed Beam. The forced transverse vibration of the Beam with a moving external force has been considered. From this it follows compression softening effect of Prestressed Beams. A detailed comparison between the calculating results for the Prestressed and the non-Prestressed Beam is also presented.
Joh W Ull - One of the best experts on this subject based on the ideXlab platform.
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behavior of Prestressed Beam strengthened with external tendons
Journal of Structural Engineering-asce, 2000Co-Authors: Ayaho Miyamoto, Katsuji Tei, Hideaki Nakamura, Joh W UllAbstract:The prestressing technique using external tendons can be considered an effective method of strengthening bridges deteriorating due to increasing overloading and progressive structural aging. In order to analytically investigate the dynamic behavior of Prestressed composite girder bridges, strengthened with external tendons, this paper focuses on a simply supported Prestressed composite girder with alternative prestressing levels, eccentricity of the attached tendons, and tendons properties. The accuracy of the proposed analysis is verified by comparison with the results of dynamic tests on large-scale Prestressed composite girders. Furthermore, as a practical example, the results of a dynamic test in which the strengthening method is applied to an actual bridge are discussed.
Clement Tchawoua - One of the best experts on this subject based on the ideXlab platform.
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the effect of nonlinear damping on vibrational resonance and chaotic behavior of a Beam fixed at its two ends and Prestressed
Communications in Nonlinear Science and Numerical Simulation, 2015Co-Authors: T Djomo L M Mbong, Siewe M Siewe, Clement TchawouaAbstract:Abstract This research work is based on the study of the dynamic of one-degree-of freedom nonlinear oscillator representing a built-in clamped–clamped Prestressed Beam model with a nonlinear damping. First of all, we model this moving structure where we regard the perturbations as a combination of both low-frequency force and high-frequency force. Then, we analyze the occurrence of vibrational resonance, where the response consists of a slow motion and a fast motion respectively with low and high frequencies. Through this, we obtain an approximate analytical expression of the response amplitude and we determine the values of the low frequency and the amplitude of the high-frequency force at which vibrational resonance occurs. The theoretical predictions are found to be in good agreement with numerical results. Moreover, for fixed parameters values of the system, as the nonlinear damping vary, we found appearance and the disappearance of resonance with or without cross-well motion. Secondly, we study the chaotic dynamic of the Beam. In this case, critical values of perturbation parameters for the onset of the chaotic motion are specified using Melnikov’s method. Hence, the global dynamical changes of the system have been examined by plotting phase portrait, bifurcation diagram and their corresponding Lyapunov exponent.