scholarly journals Fatigue Characteristics of Prestressed Concrete Beam under Freezing and Thawing Cycles

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yuanxun Zheng ◽  
Lei Yang ◽  
Pan Guo ◽  
Peibing Yang
Keyword(s):  
Fatigue Life ◽  
Prestressed Concrete ◽  
Life Prediction ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Prestressed Concrete Beam ◽  
Fatigue Characteristics ◽  
Freezing And Thawing Cycles

In order to reveal the influence of freezing and thawing on fatigue properties of the prestressed concrete beam, a kind of novel freeze-thaw test method for large concrete structure components was proposed, and the freeze-thaw experiments and fatigue failure test of prestressed concrete hollow beams were performed in this paper. Firstly, the compressive strength and dynamic elastic modulus of standard specimens subjected to different numbers of freeze-thaw cycles (0, 50, 75, and 100) were determined. Then, the static and dynamic experiments were performed for prestressed concrete beams under different freeze-thaw cycles. Depending on the static failure test results, the fatigue load for the prestressed concrete beam model was carried out, the fatigue tests for prestressed concrete beam under freezing and thawing cycles were done, and the influence of fatigue loading times on dynamic and static characteristics of prestressed concrete beam was also studied. Finally, the relation between fatigue characteristics and numbers of freeze-thaw cycles was established, and the fatigue life prediction formulas of prestressed concrete beams under freeze-thaw cycles were developed. The research shows that the freezing and thawing cycles had obvious influence on fatigue life, and the freezing and thawing cycles should be taken into account for life prediction and quality evaluation of prestressed concrete beams.

scholarly journals Flexural Behavior of Post-Tensioned Concrete Beams with Multiple Internal Corroded Strands

2020 ◽  
Vol 10 (22) ◽  
pp. 7994
Author(s):  
Chi-Ho Jeon ◽  
Chang-Su Shim
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Safety Issue ◽  
Material Model ◽  
Flexural Behavior ◽  
Bending Test ◽  
Material Models ◽  
Strain Compatibility ◽  
Prestressed Concrete Beam

The corrosion of prestressing steel in prestressed concrete bridges is a critical safety issue. To evaluate the strength of a prestressed concrete beam with corroded strands, it is necessary to know the mechanical properties of the corroded strands in terms of their tensile strength and ductility. In this study, material models were suggested using tensile tests of corroded strands which had been taken from existing bridges. Five prestressed concrete beams with multiple internal corroded strands of different corrosion levels and locations were fabricated and tested using the three-point bending test. The beams with corroded strands near the support did not show meaningful flexural behavior changes, while the beams with corrosion in the mid-span showed significant strength reduction. In order to suggest the appropriate evaluation of the flexural strength of a prestressed concrete beam with corroded strands, material models of the corroded strands were divided into two model categories: a bi-linear material model and a brittle material model. Strength evaluations of the corroded prestressed concrete beams according to fps approximation and strain-compatibility using OpenSEES were conducted. Results suggested the use of the strain compatibility method only when the section loss was greater than 5%.

Experimental Study on Mechanical Performance of Unbonded and Bonded Prestressed Concrete Beams

2012 ◽  
Vol 178-181 ◽  
pp. 2387-2392
Author(s):  
Jian Su ◽  
Nan Gai Yi ◽  
Zong Guang Sun ◽  
Yang Bai ◽  
Ai Guo Zhang
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Mechanical Performance ◽  
Concrete Beams ◽  
Stress And Strain ◽  
Strain Variation ◽  
Yield Strain ◽  
Prestressed Concrete Beam ◽  
Bearing Load ◽  
Prestressed Reinforcement

The experiment which based on the stress performance of unbonded and bonded prestressed concrete beam, has made a systematically research on the stress and strain variation law of pretressing tendon in the aforementioned reinforcement prestressed concrete structure. When the bonded prestressed concrete beam bearing load, there is a larger variation in stress and strain of prestressing reinforcement along the length. The maxima of stress and strain of prestressing reinforcement in bonded prestressed concrete beam appears in midspan, it is achieved the yield stress and yield strain, the minima appears in bearing, the stress and strain of prestressing reinforcement in bonded prestressed concrete beam is proportional to the distortion. The stress and strain of prestressed reinforcement in unbonded prestressed concrete beam is almost the same along the length.

Shear Capacity Research on Transversely Reinforced Concrete Beams

2015 ◽  
Vol 744-746 ◽  
pp. 283-287
Author(s):  
Can Liu
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Great Influence ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Force Level ◽  
Prestressed Concrete Beam ◽  
Prestressing Force

Inner transverse prestressed bars were used to enhance the shear capacity of concrete beams in this paper, which can be used in transformer beams to reduce the sectional size. Two transversely prestressed one ordinary concrete beams were tested and calculated by finite element method, and the following conclusions can be drawn: (a)The shear capacity of transversely prestressed concrete beam increase rapidly with the increase of the prestressing force level, which means that prestressing force level has a great influence on the shear capacity of transversely prestressed concrete beam. (b) The transverse prestressing bars can efficiently enhance the anti-crack performance of the reinforced concrete beams.

Test Research of Prestressed Concrete Beams with CFRP under Low Cyclic Loading

2010 ◽  
Vol 163-167 ◽  
pp. 3848-3852
Author(s):  
De Bao Jiang ◽  
Xiao Jing Gu
Keyword(s):  
Cyclic Loading ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Test Results ◽  
Root Structure ◽  
Reinforcement Effect ◽  
Prestressed Concrete Beam ◽  
Number Of Layers ◽  
Low Cyclic Loading

Through testing it is obtained that force and the damage that 1 root structure of prestressed concrete beams strengthened and 3 different layers CFRP reinforced stickup prestressed concrete beams under cyclic loading. This test results show that CFRP reinforcement effect of prestressed concrete beams is obvious, and at the same time the cracking of prestressed concrete beam has also has certain reinforcement effect; But the CFRP reinforcement effect is proportional to the number of layers.

Ductility of Partially Prestressed Concrete Beam

2006 ◽  
Vol 302-303 ◽  
pp. 720-724
Author(s):  
Jin Sheng Du ◽  
Xue Liang Chang
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Prestressed Concrete Beam ◽  
Ductility Factor ◽  
Curvature Ductility

Ductility of partially prestressed concrete beams was numerically analyzed. For a given value of reinforcement index, corresponding curvature ductility factors of an unbonded prestressed concrete beam as well as a bonded prestressed concrete beam are analyzed and compared. It is generally observed that, when reinforcement index is between 0.20 and 0.30, the ductility factor of an unbonded beam is higher than that of bonded one about 10 to 15 percent. While reinforcement index is between 0.15 and 0.20, the ductility factor of an unbonded beam is near that of bonded one. When reinforcement index we is smaller than 0.15, the ductility factor of an unbonded beam is usually lower than that of bonded one about 10 to 15 percent.

Evaluation of Flexural Performance for Prestressed Concrete Beams with FRP Tendons

2011 ◽  
Vol 383-390 ◽  
pp. 3128-3133
Author(s):  
Jiang Yong Cai ◽  
Zhi Feng Tu ◽  
Su Min Gong ◽  
Li Zhuang
Keyword(s):  
Theoretical Approach ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Flexural Behavior ◽  
Moment Capacity ◽  
Flexural Performance ◽  
Prestressed Concrete Beam

Prestressed concrete beams with vertically distributed FRP tendons possess some flexural performance obviously different from prestressed concrete beams with steel tendons. This paper provides a complete theoretical approach to analyze and evaluate the flexural behavior of prestressed concrete beams with FRP tendons. Calculation and analysis results show that a prestressed concrete beam with FRP tendons designed at balanced ratio reaches the maximum of its deformability. The increase of prestressing ratio and number of reinforcement layer will increase, respectively, its moment capacity but simultaneously decrease its deformability.

Study on a New Linear Arrangement of Prestressed Concrete Beam

2011 ◽  
Vol 94-96 ◽  
pp. 1471-1475
Author(s):  
Chun Bao Li ◽  
Qing Wang
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Fundamental Principle ◽  
Torsional Moment ◽  
Linear Arrangement ◽  
Prestressed Concrete Beam ◽  
Torsion Moment ◽  
Load Tests ◽  
Prestressed Reinforcement

A new kind of prestressed concrete beams with spiral broken line cables subjected to torsions is present based on the fundamental principle of equivalent loads of prestressed reinforcement. It carried out the emulation analyses and load tests of the beams on spiral broken line cables and the general prestressed concrete beams with longitudinal cables. The results showed that the spiral broken line cables effectively postpone the cracking of the beam and increased both crack torsional moment and ultimate torsion moment, and kept some ductility.

Study on Bond-Slip Behavior of the Channel Steel Connectors at the End of Novel Prefabricated Prestressed Concrete Beams

2013 ◽  
Vol 353-356 ◽  
pp. 3593-3597
Author(s):  
Jiang Chuan Wu ◽  
Ji Wen Zhang ◽  
Dong Yang
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Bond Slip ◽  
Shear Connectors ◽  
Finite Element Software ◽  
Prestressed Concrete Beam ◽  
Loading Effects ◽  
Stress States

The channel steel connectors of novel prefabricated prestressed concrete beam play an extremely important role in structures. They act as the connectors of prefabricated beams and columns and support the prefabricated beams temporarily at construction stage, work as shear connectors of the adjoining faces between the old and new concrete at using stage. But they are easy to be bond slip failure for its complicated stress states. To analyze their mechanical behavior and failure mode, the interaction between concrete and channel steels is considered by adopting the spring unit and nonlinear analysis with finite element software ANSYS. The results indicate that the channel steel connectors of novel prefabricated prestressed concrete beam are effective in bearing various loading effects and meet the requirements of prefabricated structures.

Parametric Study on Reinforced Concrete Beams with Transversely Prestressed Bars

2011 ◽  
Vol 105-107 ◽  
pp. 912-917
Author(s):  
Can Liu ◽  
Bo Wu ◽  
Kai Yan Xu
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Parametric Study ◽  
Concrete Beam ◽  
Steel Plate ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Force Level ◽  
Prestressed Concrete Beam ◽  
Prestressing Force

This paper presents a method that using inner transverse prestressing bars to enhance the shear capacity of concrete beams, which can be used in new transformer beams to decrease the sectional dimensions. Four transversely prestressed concrete beams and one ordinary reinforced concrete beam were tested. The nonlinear finite element method was applied to analyze them, parametric study was carried out to analyze the behavior of transversely prestressed concrete beam, and the following conclusions can be drawn: (a) With the increase of the prestressing force level, the shear capacity of transversely prestressed concrete beam increase rapidly, which means that prestressing force level has a significant effect to the shear capacity of transversely prestressed concrete beam. (b) If the area of transversely prestressing bars is almost same, the transverse bars with smaller diameter and smaller spacing can enhance shear capacity of transversely prestressed concrete beam more efficiently. (c) If steel plate of 100 mm×350 mm×16 mm being changed to steel padding of 100mm×100mm×16 mm the shear capacity of transversely prestressed concrete beam will decrease little. It means in the actual engineering the steel plate can be changed to steel padding, and then the amount of steel will be reduced.

scholarly journals Performance of Post-Fire Composite Prestressed Concrete Beam Topped with Reinforced Concrete Flange

2018 ◽  
Vol 4 (7) ◽  
pp. 1595
Author(s):  
Nibras Abbas Harbi ◽  
Amer F. Izzet
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reference Beam ◽  
Effect Of Temperature ◽  
Load Carrying Capacity ◽  
Prestressed Concrete Beam ◽  
Load Carrying

The performance of composite prestressed concrete beam topped with reinforced concrete flange structures in fire depends upon several factors, including the change in properties of the two different materials due to fire exposure and temperature distribution within the composition of the composite members of the structure. The present experimental work included casting of 12 identical simply supported prestressed concrete beams grouped into 3 categories, depending on the strength of the top reinforced concrete deck slab (20, 30, and 40 MPa). They were connected together by using shear connector reinforcements. To simulate the real practical fire disasters, 3 composite prestressed concrete beams from each group were exposed to high temperature flame of 300, 500, and 700°C, and the remaining beams were left without burning as reference specimens. Then, the burned beams were cooled gradually by leaving them at an ambient lab condition, after which the specimens were loaded until failure to study the effect of temperature on the residual beams serviceability, to determine the ultimate load-carrying capacity of each specimen in comparison with unburned reference beam, and to find the limit of the temperature for a full composite section to remain composite. It was found that the exposure to fire temperature increased the camber of composite beam at all periods of the burning and cooling cycle as well as the residual camber, along with reduction in beam stiffness and the modulus of elasticity of concrete in addition to decrease in the load-carrying capacity.

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