Analysis in Large Deformation of a Rigid Plastic Prestressed Beam in Ultra-High Performance Fiber-Reinforced Concrete (original) (raw)
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Numerical Study of the Flexural Behaviour of Precast Prestressed High Strength Concrete Beams
presents a finite element model developed to study the flexural behaviour of precast prestressed HSC beams using the commercial software 'Abaqus'. The material behaviour was simulated with: i) a plastic damage model for concrete; and ii) an elastic-plastic model for reinforcement with perfect bonding. The numerical model was validated by means of experimental results, being observed a good agreement.
SHORT-TERM DEFORMATIONAL ANALYSIS OF PRESTRESSED CONCRETE BEAMS USING FLEXURAL CONSTITUTIVE MODEL
Journal of Civil Engineering and Management, 2003
In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to short-term deformational analysis of flexural prestressed concrete members. The relationship of tensile concrete is based on smeared crack approach and accumulates cracking and the tension stiffening effects. The Flexural constitutive model was applied in a simple engineering technique based on principles of strength of materials and the layered approach. To assess accuracy of the technique, deflections have been calculated for experimental prestressed concrete beams reported in the literature. Comparison has been earned out with the predictions of the well-known design code methods of different countries.
Journal of Civil Engineering and Management, 2005
In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to short-and long-term deformational analysis of flexural partially prestressed concrete members. The effect of tension stiffening and non-linear time effects of creep and shrinkage are taken into account. Effective modulus method is used for modelling long-term deformations. The proposed calculation technique is based on the layered approach and use of material stress-strain relationships. Curvatures prediction results were tested against experimental data of partially prestressed concrete beams reported in literature.
Several experimental tests have demonstrated the effectiveness of steel fibers in substituting the minimum code required shear reinforcement in beams, particularly in precast high performance concrete structures. Despite the large number of experimental results available, only a few numerical studies have been so far published concerning fiber reinforced concrete structures. The behavior of full scale steel fiber reinforced concrete beams is herein analysed using a smeared crack damage model provided by the latest release of ABAQUS (V. 6.3). The numerical model is validated against the experimental results obtained on full scale FRC beams. The numerical results allow to correctly predict the experimental response, particularly with respect to the first cracking point, the initial crack pattern, and its development. The results allow a better understanding of fiber reinforced concrete structures under shear loading and will be used as a basis for developing a new design procedure for such kind of structures.
Accurate finite element modeling of pretensioned prestressed concrete beams
Engineering Structures, 2015
This paper presents a nonlinear finite element model for pretensioned prestressed concrete beams. The study presented here is an important step because it is, perhaps, for the first time that a prestressed concrete beam has been successfully modeled by nonlinear finite element analysis, allowing for plasticity and damage behavior of concrete and slip-bond failure behavior for strands. The model faithfully follows the actual loading history realistically, allowing for the construction sequence including the process of transfer of strand force. Existing results of finite element analysis are not reliable in the critical regions. Even the very recent ones do not seem to have been successful. In this study, all material and bond models used are based on experimental data. The simulation results are validated with data from actual load testing. Apart from examining the behavior of the beam up to the limit state, the response of the damaged beam after local bonded composite patch repair is also considered. For this purpose, the prestressed concrete beam specimens are manufactured and tested in the laboratory before and after they have been repaired with bonded composite patches. Satisfactory agreement between finite element predictions and test results of the virgin beam is noted.
Nonlinear Finite Element Analyses of Prestressed Concrete Beams Failing in Shear
Shear failure of prestressed concrete beams, more properly called diagonal tension failure, is difficult to predict accurately. In spite of many decades of experimental research and the use of highly sophisticated analytical tools, it is not yet fully understood; furthermore, if a beam without properly designed shear reinforcement is overloaded to failure shear collapse is likely to occur suddenly with no advanced warning of distress which is in strong contrast with the nature of flexural failure. Because of these different behavior, prestressed concrete beams are generally provided with special shear reinforcement to insure that flexural failure would occur before shear failure if the member should be severely overloaded. Three-dimensional nonlinear finite element techniques have been used to successfully model prestressed concrete beams that fail in shear. A 20-noded isoparametric brick element has been used to model the concrete. The reinforcing and the prestressing steel bars are idealized as axial members embedded within the brick elements. Perfect bond between the concrete and the reinforcing bars is assumed. The behaviour of concrete in compression is simulated by an elasto-plastic work hardening model followed by a perfect plastic response, which is terminated at the onset of crushing. In tension, a fixed smeared crack model has been used with a tension-stiffening model to represent the retained post-cracking tensile stress. Also a shear retention model that modified the shear modulus after cracking is used. The nonlinear equations of equilibrium have been solved by 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 by using the 27-point Gaussian type rule. Two types of prestressed concrete beams (I-section and rectangular) have been analyzed and the finite element solutions were compared with the available 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, also the effect of some parameters that affect the shear strength of the prestressed concrete beams were also studied. The studies included the effect of concrete compressive strength, shear span to depth ratio, prestressing stress, prestressing reinforcement amount, and the web reinforcement amount.The finite element results were also compared graphically with the experimental results of other researchers. In general, good agreement between the finite element and experimental results was obtained throughout this work. Comparison study also made between the finite element results and the ACI-Code provisions for shear strength in prestressed concrete beams, in general the ACI-Code provision seems to be conservative in most cases, although a modification to the ACI-Code Equations to include the effect of shear span to depth ratio and the effect of prestressing reinforcement ratio were suggested.
Analysis of prestressed fibre-reinforced concrete beams
Proceedings of the ICE - Bridge Engineering, 2009
This paper presents the test results of 12 partially prestressed concrete flexural beams reinforced with steel fibres that failed in flexure over partial or full depth. The variables considered were strength grades of concrete (35, 65 and 85 MPa) and the presence of steel fibres in the cross-section of the beam (web, flange or full depth). Three-dimensional finite element analysis of the prestressed beams was carried out to assess the non-linear behaviour of concrete, for example post-peak softening, concrete cracking strain softening, tension stiffening, bond-slip and yielding of reinforcement. Also, the effects of the addition of steel fibres in the concrete (increase in tensile strength and control of crack width due to the bridging of fibres across the crack interface) were modelled. The bond-slip behaviour of longitudinal reinforcements (steel fibres, prestressing wire and deformed bars) was accounted for to capture the structural stiffness of the concrete beam accurately. The ...
A design model for fibre reinforced concrete beams pre-stressed with steel and FRP bars
Composite Structures, 2012
This paper presents a design oriented model to determine the moment-curvature relationship of elements of rectangular cross section failing in bending, made by strain softening or strain hardening fibre reinforced concrete (FRC) and reinforced with perfectly bonded pre-stressed steel and fibre reinforced polymeric (FRP) bars. Since FRP bars are not affected by corrosion, they have the minimum FRC cover thickness that guaranty proper bond conditions, while steel bars are positioned with a thicker FRC cover to increase their protection against corrosion. Using the moment-curvature relationship predicted by the model in an algorithm based on the virtual work method, a numerical strategy is adopted to evaluate the load-deflection response of statically determinate beams. The predictive performance of the proposed formulation is assessed by simulating the response of available experimental results. By using this model, a parametric study is carried out in order to evaluate the influence of the main parameters that characterize the post cracking behaviour of FRC, and the prestress level applied to FRP and steel bars, on the moment-curvature and load-deflection responses of this type of structural elements. Finally the shear resistance of this structural system is predicted.
D numerical modelling on prestressed concrete beams
This paper presents a model for the analysis of reinforced and prestressed concrete frame elements under combined loading conditions, including axial force, biaxial bending, torsion and biaxial shear force. The proposed model is based on the simple kinematic assumptions of the Timoshenko beam theory and holds for curved three dimensional frame elements with arbitrary cross-section geometry. The control sections of the frame element are subdivided into regions with 1D, 2D and 3D material response. The constitutive material model for reinforced and prestressed concrete follows the basic assumptions of the Modified Compression Field Theory with a tangent-stiffness formulation. The validity of the model is established by comparing its results with several well-known tests from the literature. These simulations include a variety of load combinations under bending, shear and torsion. The analytical results show excellent agreement with experimental data regarding the ultimate strength of the specimen and the local strain response from initiation of cracking to ultimate load.
Simulation of Flexural Behavior of Damaged Prestressed Concrete Beam by Finite Element Method
Finite element model is applied to simulate the flexural behavior of bonded post tension prestressed concrete (PC) T beam. Flexural behavior of PC beam is characterized by load-deformation relationship in both linear elastic uncrack and nonlinear after cracking stage. Finite element analysis software, ANSYS, is utilized the simulation of flexural behaviors both loading and unloading path. Nonlinearity of materials are considered and taken into account. The developed model is verified by experimental results. The study finds good agreement between analytical and experimental results. Degradation of PC girder due to overload beyond cracking can be expressed by the loss of flexural stiffness and permanent deformation after unloading due to accumulated cracks. The verified finite element model (FEM) can be parametrically used to predict flexural behavior of PC beam in various levels of overloading.