Modelling of a prestressed beam without concrete-to-steel bond (original) (raw)
Comparison of Dynamic Characteristics of Prestressed and Reinforced Concrete Beams
Düzce Üniversitesi Bilim ve Teknoloji Dergisi, 2019
To determine the dynamic characteristics of bridges built with prestressed and reinforced concrete beams, the dynamic properties of such beams should be known. Prestressing force is applied to the prestressed concrete (PSC) beam, unlike reinforced concrete (RC) beam. In this study, it is aimed to compare the dynamic properties of PSC and RC beams with the same material, section properties and effective span length. Dynamic properties such as the mode shapes and periods of the PSC and RC beam were determined by means of the formulation found in the literature and a computer program that uses the finite element method. For this study I-beam with 0.90m height and 15m effective span length was selected as an example. The selected beam was considered separately as PSC and RC. In the PSC beam, eight low-relaxation Grade270 prestressing strand with 15mm (0.6 in.) diameter were used, unlike reinforced concrete beams. Three dimensional finite element models (FEM) of PSC and RC beam were cons...
Behavior of bonded and unbonded prestressed normal and high strength concrete beams
HBRC Journal, 2012
The major disadvantage of using ordinary reinforced concrete (RC) elements is the corrosion of steel, which occurs due to effect of cracks in tension zones. The main advantage of the fully prestressed concrete system is the absence of cracks in the concrete at the nominal service load and therefore better durability will be achieved. Combining the PC system with the use of high strength concrete is a milestone, which will potentially result in a new design approach. The disadvantage of the use of this combination is referred to the reduced ductility of concrete members. This paper presents an experimental program conducted to study the behavior of bonded and unbounded prestressed normal strength (NSC) and high strength concrete (HSC) beams. The program consists of a total of nine beams; two specimens were reinforced with non-prestressed reinforcement, four specimens were reinforced with bonded tendons, and the remaining three specimens were reinforced with unbonded tendons. The overall dimensions of the beams are 160 · 340 · 4400-mm. The beams were tested under cyclic loading up to failure to examine its flexural behavior. The main variables in this experimental program are nominal concrete compressive strength (43, 72 and 97 MPa), bonded and unbonded tendons and prestressing index (0%, 70% and 100%). Theoretical analysis using rational approach was also carried out to predict the flexural behavior of the specimens. Evaluation of the analytical work is introduced and compared to the results of the experimental work.
Materialwissenschaft und Werkstofftechnik, 2014
Firstly, the effect of traditional reinforcementprestressed reinforcement ratio on the behaviour of concrete beams up to failure was experimentally investigated. The beams were 10 m long and 0.5 m high, with different ratios of traditional and prestressed reinforcement. The total quantity of reinforcement in each beam was selected to provide their equal ultimate bending bearing capacity. Deflections, stresses in concrete, traditional and prestressed reinforcement, as well as concrete cracks, were monitored until the beams failure. Using the previously developed numerical model of authors of this paper for static analysis of spatial frame structures, which can simulate main nonlinear effects of their behaviour, then numerical analysis of tested beams was performed. Good agreement was obtained between the experimental and the numerical results, which confirms the possibility of practical application of the adopted numerical model. Main conclusions and recommendations for practical applications according to results of performed tests are given at the end.
Finite element analysis of the beam strengthened with prefabricated reinforced concrete plate
Scientific Research and Essays, 2010
Various strengthening methods were frequently carried out in the world to strengthen weaker cross section beams. In this study, one beam strengthened by bonding with a prefabricated plate which has 80 mm thickness underneath and one control beam were produced. The specimens were tested in the laboratory and a single load was applied on the middle of the beam. The results of the experiments were compared with the results obtained from the beam modelled with ANSYS finite element program. When the results of the experiments were compared with the modelled computer program, it was shown that the results of computer model gave similar results to the real behaviour.
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.
An analytical model to determine the shear capacity of prestressed continuous concrete beams
Structural reassessments of existing older prestressed concrete bridges based on current German standards often uncover substantial deficits in terms of the required shear reinforcement in the main girders in longitudinal direction. This is due to the negligence of the concrete shear capacity that can be determined using the compressive arch model as long as plane sections remain plane and only vertical cracks due to bending occur in state II. In case of inclined cracks due to shear plane sections do not remain plane. An extended compressive arch model is derived from experimental and numerical investigations that can determine the concrete shear capacity analytically even in case of existing inclined cracks in state II. This model also takes into account that parts of the acting shear forces are covered by the truss model.
Study of the flexural strengthening of RC concrete and prestressed concrete beams
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON SUSTAINABLE MATERIALS AND STRUCTURES FOR CIVIL INFRASTRUCTURES (SMSCI2019)
Concrete is strong in compression, but weak in tension its tensile strength. Due to such a low tensile capacity, flexural cracks develop at early stages of loading. In order to reduce or prevent such cracks from developing, a concentric or eccentric force is imposed in the longitudinal direction of the structural element. According to that, we studied RC concrete and prestressed concrete in flexural strengthening and analyzed the review of displacement of RC & prestressed concrete beams. The idea is to reach a definite conclusion, the prestressed concrete beams more effective as compared to reinforcement concrete beams in flexural strengthening. Software programming is a general purpose structural analysis and design program with applications primarily in the building industry-commercial buildings, bridges and highway structures, industrial structures, chemical plant structures, dams, retaining walls, turbine foundations, culverts and other embedded structures, etc. There is a very good understand all aspect of prestressed concrete beam better than as compared to reinforced concrete beam in flexural strengthening. The aim of this research is to compare the economics, durability and structural analysis of the reinforced concrete and prestressed concrete beams.
Design And Tests Of Prestressed Concrete Beams
Fire Safety Science
A prestressed TT beam had been designed considering the ultimate limit state of bending, and considering a temperature distribution given by a graph which was valid for a section with a similar shape. When tested in a furnace, it proved to have a fire resistance of only 79 minutes instead of the 2 hours foreseen by the calculation. An investigation was made, with the help of numerical modelling, to explain the reasons of the failure and to design a new specimen. Some modifications were introduced to increase the resistance to bending forces, to shear forces and to the slip of the tendons. A modified specimen behaved satisfactory in a second test. The formula proposed in Eurocode 2 for the shear resistance of reinforced concrete elements at ambiant temperature has been adapted for the elevated temperature situation and its application allowed to accurately predict the failure mode observed in the fiist test. FIGURE 1 : half section in the elements. 24,OO 4
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.
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.