Experimental Study on Measuring the Steel Stress via FBG Sensors

2014 ◽  
Vol 548-549 ◽  
pp. 663-667 ◽  
Author(s):  
Hong Wei Lin ◽  
Yu Xi Zhao
Keyword(s):  
Experimental Study ◽  
Bond Stress ◽  
Strain Gauges ◽  
Bond Behavior ◽  
Fbg Sensor ◽  
Pullout Tests ◽  
Steel Bar ◽  
Steel Bars ◽  
Fbg Sensors

Studying the bond stress-slip relationship between concrete and corroded steel bar by cutting the steel bars into two separate parts and attaching electric strain gauges in the slots is no longer suitable. To overcome the disadvantages of electric strain gauges in the measuring the stress of corroded steel bars, this paper introduced a new kind of FBG sensor measuring steel stress. By calibration tests, the proportion coefficient between variation of wavelength and steel strain was confirmed as 0.0012. The bond behavior between concrete and steel bar was also investigated by performing pullout tests on beam end specimens.

scholarly journals Experimental Study on Bond Behavior between Plain Reinforcing Bars and Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Guohua Xing ◽  
Cheng Zhou ◽  
Tao Wu ◽  
Boquan Liu
Keyword(s):  
Aluminium Alloy ◽  
Structural Characteristics ◽  
Bond Stress ◽  
Reinforcing Bars ◽  
Bond Slip ◽  
Bond Behavior ◽  
Reinforcing Bar ◽  
Test Parameters ◽  
Steel Bars ◽  
Plain Bars

To evaluate the bond behavior between the reinforcing bar and surrounding concrete, a total of six-group pullout specimens with plain steel bars and two-group specimens with deformed steel bars, serving as a reference, are experimentally investigated and presented in this study. The main test parameters of this investigation include embedment length, surface type of reinforcing bars, and bar diameter. In particular, the bond mechanism of plain steel reinforcing bars against the surrounding concrete was analyzed by comparing with six-group pullout specimens with aluminium alloy bars. The results indicated that the bond stress experienced by plain bars is quite lower than that of the deformed bars given equal structural characteristics and details. Averagely, plain bars appeared to develop only 18.3% of the bond stress of deformed bars. Differing from the bond strength of plain steel bars, which is based primarily on chemical adhesion and friction force, the bond stress of aluminium alloy bars is mainly experienced by chemical adhesion and about 0.21~0.56 MPa, which is just one-tenth of that of plain steel bars. Based on the test results, a bond-slip model at the interface between concrete and plain bars is put forward.

Numerical Simulation of Bond Properties of Steel Bars in Concrete with Machine-Made Sand

2012 ◽  
Vol 238 ◽  
pp. 176-180
Author(s):  
Shun Bo Zhao ◽  
Xin Xin Ding ◽  
Shi Ming Liu
Keyword(s):  
Concrete Strength ◽  
Experimental Studies ◽  
Theoretical Method ◽  
Finite Element Models ◽  
Bond Properties ◽  
Ansys Software ◽  
Bond Slip ◽  
Bond Behavior ◽  
Steel Bar ◽  
Steel Bars

Based on the experimental studies, finite element models were built using ANSYS software to simulate the bond properties of steel bars in machine-made-sand concrete (MSC), which considered the nonlinear bond behavior of interface between steel bar and MSC. The concrete strength and the bond length of steel bar are considered as the main parameters for calculation. The complete bond-slip curves of plain and deformed steel bars are well simulated comparing those obtained from the experimental studies. The study gives an theoretical method to analyze the bond properties of steel bar in MSC.

Bond-Slip Constitutive Behavior between Fiber-Reinforced Polymer and Masonry

2012 ◽  
Vol 446-449 ◽  
pp. 3165-3170 ◽  
Author(s):  
Yi Zheng ◽  
Jin Qing Jia ◽  
Li Li ◽  
Shi Kuan You
Keyword(s):  
Constitutive Models ◽  
Bond Stress ◽  
Fiber Reinforced Polymer ◽  
Strain Gauges ◽  
Test Results ◽  
Hydraulic Jack ◽  
Bond Slip ◽  
Bond Behavior ◽  
Frp Composite ◽  
Reinforced Polymer

To study the bond behavior and the force transference of FRP plates adhered to masonry. In this paper, experiments of anchorage strength of FRP attached to masonry are done, a 100KN capacity hydraulic jack activated by a manual pump was used to load the specimen. The tensile strength was measured by using a loading transducer, and strain gauges were mounted directly onto the surface of the FRP composite to measure the strain during application of load. Besides the strain and bond stress development and distribution under every grade of loading were studied. Test results show that the maximum local bond stress is not influenced by the FRP bond length, instead it increases with masonry strength. At the same time, the local bond stress--slip curve is obtained. Based on the test results, two new bond stress-slip constitutive models between FRP and masonry were proposed and they turned out to be good matches to the experimental results, which indicate its valuable references for the corresponding codes and engineering applications.

scholarly journals Effect of Coating Thickness on Bond Behaviors of Polymer Cement Coated Plain Steel Bar with Concrete and Finite Element Modeling

2016 ◽  
Vol 10 (1) ◽  
pp. 571-577 ◽  
Author(s):  
Xiong Yuanliang ◽  
Wang Kunrong ◽  
Liu Zhiyong ◽  
Yang Zhengguang
Keyword(s):  
Finite Element ◽  
Bond Strength ◽  
Coating Thickness ◽  
Failure Modes ◽  
Bond Behavior ◽  
Finite Element Software ◽  
Pullout Tests ◽  
Steel Bar ◽  
Contact Surfaces ◽  
Hot Rolled

The pullout tests were carried out to investigate the effect of coating thickness on bond behavior (failure modes, bond strength, bond stress slip curves) between hot rolled plain steel bar (HPB) coated with polymer cement based coating and concrete. The results indicated the failure mode of the specimens is pullout. Suitable coating thickness could enhance the bond strength of steel bar embedded with concrete. By using contact surfaces with cohesive behavior in finite element software, the slip between coated plain steel bar and concrete can be realized. The results of numerical simulation are close to that of experiments, indicating that the model using contact surfaces with cohesive behavior can reasonably predict the results of pullout tests of HPB in concrete.

Experimental Study on Effects of Fatigue Loading History on Bond Behavior between Steel Bars and Concrete

2016 ◽  
Vol 711 ◽  
pp. 673-680 ◽  
Author(s):  
Zhiwen Ye ◽  
Wei Ping Zhang ◽  
You Hu ◽  
Xiang Lin Gu
Keyword(s):  
Experimental Study ◽  
Bond Strength ◽  
Fatigue Loading ◽  
Critical Value ◽  
Concrete Cover ◽  
Repeated Loading ◽  
Loading History ◽  
Bond Behavior ◽  
Pull Out ◽  
Steel Bars

This paper presents an experimental investigation on the influence of fatigue loading history on bond behavior between steel bars and concrete. Reinforced concrete specimens were subjected to fatigue loadings with different amplitudes and cycles before undergoing eccentric pull-out tests. Tests revealed that all specimens failed with the splitting of the concrete cover. With increased loading cycles, the concrete in front of transverse ribs usually becomes denser at the beginning. Meanwhile, the initial bond stiffness and the bond strength increased, while the slip corresponding to the peak bond stress decreases. With the further increase of loading cycles, the bond strength begins to decrease after it reaches a critical value. This study determined that for specimens subjected to repeated loading with a larger amplitude, fewer cycles are needed for the bond strength to go up to the critical bond strength.

Behavior of Circular Concrete Columns Repaired with Steel Bars and Wire Mesh-Mortar

2010 ◽  
Vol 133-134 ◽  
pp. 1247-1252 ◽  
Author(s):  
Feng Feng Li ◽  
Xiao Yong Wu ◽  
Yan Zhou ◽  
Xiao Hua Lu ◽  
Guang Jing Xiong
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Concrete Columns ◽  
Wire Mesh ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Concrete Compressive Strength ◽  
Reinforced Polymer ◽  
Steel Bar ◽  
Steel Bars

In order to increase the strengthening efficiency of steel bar mat-mortar (BM) jacket and wire mesh-mortar (WM) jacket around existed circular concrete columns, an attempt to strengthen the columns with hybrid bar mat-wire mesh-mortar (HBWM) jacket was proposed. A comparatively experimental study on axial compression behaviors of concrete columns wrapped with three different strengthening systems, namely BM, HWBM and carbon fiber reinforced polymer (CFRP) was performed. The experiment results showed that much more cracks appeared in HWBM columns compared with those in BM columns. As a result, on the premise that the concrete compressive strength of the HWBM columns increased 90% compared with that of the BM columns, the ductility of the HWBM columns reached about twice as that of the BM columns. The increase of the concrete compressive strength of CFRP strengthened columns was higher than those of HWBM and BM strengthened columns. The ductility of CFRP strengthened columns, however, was obviously lower than that of HWBW columns.

scholarly journals Basic Mechanical Properties of Duplex Stainless Steel Bars and Experimental Study of Bonding between Duplex Stainless Steel Bars and Concrete

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2995
Author(s):  
Qingfu Li ◽  
Yunqi Cui ◽  
Jinwei Wang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Concrete Strength ◽  
Concrete Cover ◽  
Bond Stress ◽  
Reinforcing Steel ◽  
Anchorage Length ◽  
Steel Bar ◽  
Steel Bars

In recent years, as a result of the large-scale use of stainless steel bars in production and life, people’s demand for stainless steel bars has increased. However, existing research information on stainless steel bars is scant, especially the lack of research on the mechanical properties of duplex stainless steel bars and the bonding properties of duplex stainless steel bars to concrete. Therefore, this paper selects 177 duplex stainless steel bars with different diameters for room temperature tensile test, and then uses mathematical methods to provide suggestions for the values of their mechanical properties. The test results show that the duplex stainless steel bar has a relatively high tensile strength of 739 MPa, no significant yield phase, and a relatively low modulus of elasticity of 1.43 × 105 MPa. In addition, 33 specimens were designed to study the bonding properties of duplex stainless steel bars to concrete. In this paper, the effects of concrete strength, duplex stainless steel reinforcement diameter, the ratio of concrete cover to reinforcing steel diameter, and relative anchorage length on the bond stress were investigated, and a regression model was established based on the experimental results. The results show that, with the concrete strength concrete strength from C25 to C40, the compressive strength of concrete increased by 56.1%, the bond stress increased by 27%; the relative anchorage length has been increased from 3 to 6, the relative anchorage length has doubled, and the bond stress has increased by 13%; and, the ratio of concrete cover to reinforcing steel diameter increased to a certain range on the bond stress has no significant effect and duplex stainless steel reinforcement diameter has little effect on the bond stress. The ratio of concrete cover to reinforcing steel diameter from 3.3 to 4.5 and the bond stress increased by 24.7%. A ratio of concrete cover to reinforcing steel diameter greater than 4.5 has no significant effect on the bond stress, with the average bond stress value of 20.1 MPa. The duplex stainless steel bar diameter has little effect on the bond stress for the diameters of 12 mm, 16 mm, 25 mm duplex stainless steel bar, and their average bond stress is 19.9 MPa.

Bond position function between deformed steel bars and early-age cementitious grout

2021 ◽  
pp. 136943322110157
Author(s):  
Gang Peng ◽  
Ditao Niu ◽  
Xiaopeng Hu ◽  
Xiao Wu ◽  
Yong Zhang
Keyword(s):  
Ultimate Load ◽  
Tensile Load ◽  
Stress Transfer ◽  
Bond Stress ◽  
Load Testing ◽  
Anchorage Length ◽  
Steel Bar ◽  
Steel Bars ◽  
Two Parameters ◽  
Cover Thickness

Pullout tests for the deformed steel bars in early-aged cementitious grout by considering the variables of testing ages, cover thicknesses, and diameters of steel bar were conducted, and the local bond stress–slip relationship at different positions of the anchorage length of steel bar was studied. Results indicated that, with the increase of testing age, the load-slip curves exhibited a higher ultimate load and had steeper ascending and descending branches; however, the slippage at the ultimate load exhibited a decreasing trend. Moreover, with the increase of cover thickness and diameter of steel bar, the ultimate load of pullout specimens increased obviously, while the corresponding slips generally had no obvious correlations. According to an analysis of the measured rebar strain, the distributions of the steel stress and bond stress as well as the relative slip along the embedded length were obtained under different external loads. Steel stress transfer and bond stress distribution parameters were introduced to characterize the nonuniformity of the distributions of the steel stress and bond stress along the steel bar, and the effects of the testing age, cover thickness, and diameter of steel bar on these two parameters were analyzed. Results showed that the both of these two parameters increased with the increasing tensile load, testing age, and cover thickness and with the decreasing diameter of steel bar. Thereafter, the local bond stress-slip relationships along the anchorage length and position functions reflecting the variations of these relationships were proposed.

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