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

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%.

2011 ◽  
Vol 383-390 ◽  
pp. 3128-3133
Author(s):  
Jiang Yong Cai ◽  
Zhi Feng Tu ◽  
Su Min Gong ◽  
Li Zhuang

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.


2013 ◽  
Vol 438-439 ◽  
pp. 804-806
Author(s):  
Jiong Feng Liang ◽  
Jian Bao Wang ◽  
Jian Ping Li

The flexural behavior of concrete beams reinforced with CFRP-PCPs composite rebars was studied. Experimental results showed that the deflection of beams reinforced with highly prestressed prisms is at service loads coMParable to deflection of steel reinforced beam. Flexural cracks of CFRP-PCPs composite rebars reinforced beams are hairline before prism cracking, and widened after the prism cracking. When the concrete beam was reinforced with the prestressed concrete prisms, the crack width decreased as the prestress in the prism increased.


2012 ◽  
Vol 178-181 ◽  
pp. 2387-2392
Author(s):  
Jian Su ◽  
Nan Gai Yi ◽  
Zong Guang Sun ◽  
Yang Bai ◽  
Ai Guo Zhang

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.


2015 ◽  
Vol 744-746 ◽  
pp. 283-287
Author(s):  
Can Liu

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yuanxun Zheng ◽  
Lei Yang ◽  
Pan Guo ◽  
Peibing Yang

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.


2010 ◽  
Vol 163-167 ◽  
pp. 3848-3852
Author(s):  
De Bao Jiang ◽  
Xiao Jing Gu

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.


2006 ◽  
Vol 302-303 ◽  
pp. 720-724
Author(s):  
Jin Sheng Du ◽  
Xue Liang Chang

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.


2011 ◽  
Vol 94-96 ◽  
pp. 1471-1475
Author(s):  
Chun Bao Li ◽  
Qing Wang

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.


2013 ◽  
Vol 353-356 ◽  
pp. 3593-3597
Author(s):  
Jiang Chuan Wu ◽  
Ji Wen Zhang ◽  
Dong Yang

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.


Sign in / Sign up

Export Citation Format

Share Document