scholarly journals Bond–Slip Law Between Steel Bar and Different Cement-Based Materials Considering Anchorage Position Function

2021 ◽  
Vol 8 ◽  
Author(s):  
Jie Xiao ◽  
Xiang Long ◽  
Ming Ye ◽  
Haibo Jiang ◽  
Lingfei Liu ◽  
...  
Keyword(s):  
Limit State ◽  
Critical Limit ◽  
Anchorage Length ◽  
Relative Slip ◽  
Bond Slip ◽  
Bond Performance ◽  
Steel Bar ◽  
Steel Bars ◽  
Cement Based Materials ◽  
Measured Strain

The bond performance between steel bar and cement-based materials was the prerequisite for the two materials to work together, and previous studies showed that the bond behavior of the steel bars and cement-based materials will vary with the kinds of cement-based materials. For this reason, this paper adopted 12 direct pullout test specimens including three types of concrete and two types of steel bars. The strain of the steel bar at six measuring points was measured with a strain gauge. Based on the measured strain and free end slip of the steel bars, the distribution of steel stress, bond stress, and relative slip and the bond slip relation along the anchorage length were obtained and analyzed for different concrete and different steel bars. Based on these test results of steel strain and relative slip at six measuring points, the anchorage position function could be established in consideration of anchorage position, which was conducive to the establishment of an accurate bond–slip relationship. In addition, the anchorage length of the steel bar in Engineered Cementitious Composites (ECC) calculated from the equilibrium equation of critical limit state is only half of the anchorage length calculated in the current Code for Design of Concrete Structures (GB 50010-2010) in China. It is suggested to establish the critical anchorage length formula suitable for ECC in future studies.

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.

Development Length Comparison between Australian Codes and Chinese Code on 500MPa Steel Bars

2014 ◽  
Vol 584-586 ◽  
pp. 889-893
Author(s):  
Jing Wen Su ◽  
Hai Tao Li ◽  
Li Xin Liu ◽  
A.J. Deeks ◽  
Fan Wu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Test Data ◽  
Test Results ◽  
Development Length ◽  
Anchorage Length ◽  
Steel Bar ◽  
Eurocode 2 ◽  
Steel Bars ◽  
Code Provisions ◽  
Good Agreement

This paper presents development length comparison between Chinese and Australian codes study on HRB500 steel bars in concrete. After introducing the existing code provisions about the anchorage length and experimental investigation of tensile HRB500 steel bars, the calculation approaches in different codes are compared with the test data. Additionally, the development length of tensile HRB500 reinforcement bars in AS3600-2001, Proposed Revision of AS3600, GB50010-2010 and the calculation equation proposed from test results are compared with each other in beams and slabs. It is proved that AS3600-2001 is inconsistent with other standards and the tests results and needs to be revised, while the Proposed Revision of AS3600 provided a good agreement with the test data and brings the code into line with other international codes, particularly Eurocode 2. Moreover, the Proposed Revision of AS3600 is a significant improvement on the method in AS3600-2001. The anchorage length formula in GB50010-2010 can still be used for designing HRB500 steel bar.

The Analysis of the Reliability and Design for Mechanical Anchorage of HRB500 Steel Bars

2011 ◽  
Vol 94-96 ◽  
pp. 970-974
Author(s):  
Xian Rong ◽  
Peng Cheng Liu ◽  
Xue Li
Keyword(s):  
Concrete Strength ◽  
Concrete Cover ◽  
Statistical Regression ◽  
Analysis Method ◽  
Anchorage Length ◽  
Pull Out ◽  
Steel Bar ◽  
Steel Bars ◽  
Mechanical Anchoring ◽  
Cover Thickness

The factors on mechanical anchoring performance of HRB500 steel bars, such as concrete strength, concrete cover thickness, diameter of steel bar, anchorage length of steel bar and transverse reinforcement ratio, were studied based on pull-out tests of 45 specimens. And the formula of mechanical anchoring bond strength for HRB500 steel bars was concluded by statistical regression analysis method. Through the reliability analysis, the mechanical anchoring length of design value and the table of conversion ratio between mechanical and direct anchoring length of HRB500 steel bars have been proposed. So it could be used as a basis for practical projects. The results indicate that the mechanical anchorage length of HRB500 steel bars can be still designed with the formula proposed in GB 50010-2002 “Code for design of concrete structures”.

scholarly journals STUDY ON BONDING PROPERTY OF POLYURETHANE CEMENT (PUC) TO STEEL BAR

2021 ◽  
Vol 30 (3) ◽  
Author(s):  
Kexin Zhang
Keyword(s):  
Bond Strength ◽  
Protective Layer ◽  
Stress Process ◽  
Anchorage Length ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bar ◽  
Bonding Property ◽  
Bonding Properties ◽  
Reinforcement Bar

The pull-out test of the bar and PUC is carried out in this paper, the effects of protective layer thickness, reinforcement anchorage length, diameter and shape of reinforcement on bonding properties were studied. The results show that the bond strength between reinforcement and PUC material increases with the increase of the thickness of the protective layer, but decreases with the increase of the anchorage length and diameter of reinforcement. The bond strength of bare round steel is significantly lower than that of ribbed steel, and the maximum bond strength is about 47.4% of ribbed steel. By analyzing the bond slip curve obtained from the pull-out test, the stress process of bond anchorage between reinforcement bar and PUC material is mainly summarized into three stages: the rising stage, the falling stage and the residual stage. The characteristics of the curve, the stress process and the failure mode of specimen at each stage are analyzed.

Influence of specimen dimensions and reinforcement corrosion on bond performance of steel bars in concrete

2020 ◽  
Vol 23 (9) ◽  
pp. 1759-1771
Author(s):  
Bai Zhang ◽  
Hong Zhu ◽  
Jun Chen ◽  
Ou Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Results ◽  
Reinforcement Corrosion ◽  
Element Analysis ◽  
Bond Slip ◽  
Bond Performance ◽  
Concrete Deterioration ◽  
Pull Out ◽  
Steel Bars

To study the deterioration of bond performance between concrete and corroded steel bars with designed corrosion levels of 0%, 0.5%, 1.0%, 2.0%, 5.0%, 8.0%, and 10.0%, pull-out tests were performed on cube specimens with the dimensions of 10 D × 10 D × 10 D, where D is the diameter of longitudinal rebars ( D = 14, 20, and 25 mm, respectively). The experimental results indicated that with the specimen dimensions increased, the expansive cracks induced by corrosion products appeared earlier and the maximum expansive cracking width was larger at the same corrosion levels. The bond strength and the initial bond stiffness first increased and then dramatically decreased as the concrete deterioration and reinforcement corrosion levels increased for each specimen dimension, whereas the specimens with the larger diameter ( D = 25 mm) were more sensitive to the corrosion than those with the smaller diameter ( D = 14, 20 mm). The free-end slip and the energy dissipation for each specimen dimensions, which decreased slowly with increasing corrosion levels before the corrosion-induced cracks and then weakened rapidly when the corrosion-induced cracks appeared, was almost independent of the influence on corrosion levels after the corrosion-induced cracks appeared. Based on the experimental results, a simplified expression for the calculation of residual bond stress and an empirical model of the bond–slip constitutive equation that considers the influence of reinforcement corrosion were proposed, which can be used in finite element analysis of corroded reinforced concrete.

Bond performance between SFCBs and grouted sleeves for precast concrete structures

2021 ◽  
pp. 136943322110015
Author(s):  
Yunlou Sun ◽  
Zeyang Sun ◽  
Liuzhen Yao ◽  
Yang Wei ◽  
Gang Wu
Keyword(s):  
Concrete Structure ◽  
Failure Modes ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Bond Slip ◽  
Analysis And Design ◽  
Bond Performance ◽  
Steel Bar ◽  
Critical Issues ◽  
Hybrid Reinforcement

A precast concrete structure reinforced by steel-fiber-reinforced polymer (FRP) composite bars (SFCBs) shows good durability and controllable post-yield stiffness, which makes this kind of structure suitable for marine infrastructure. The connection technology is one of the critical issues of a precast concrete structure with hybrid reinforcement. This paper presents an experimental study on the bond-slip testing (27 pullout specimens) of composite bars connected by a grouted deformed pipe splice (GDPS) connector with different bond lengths. The reinforcement included SFCBs and pure FRP bars. The test results showed that the failure modes could be classified into three categories: rebar pullout before or after the inner steel bar yielded, rupture of the FRP wrapped on the SFCB, and mixed failure of bar pullout with a partial fiber fracture. The average bond strength of the ordinary steel bar was approximately 146.8% that of the SFCB connector with the same anchored length. When the anchored length of the SFCB specimen was 15 d ( d: bar diameter), the specimen could be fully anchored to fracture. An explicit hardening bond-slip model considering the post-yield stiffness of the SFCB was used to predict the bond-slip behavior of the GDPS connector, and the experimental and analytical results agreed well with each other, which demonstrates that the proposed model could provided a reference for the analysis and design of connectors for SFCB-reinforced precast concrete structures.

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.

scholarly journals Research on bond–slip performance between pultruded glass fiber-reinforced polymer tube and nano-CaCO3 concrete

2020 ◽  
Vol 9 (1) ◽  
pp. 637-649 ◽  
Author(s):  
Zhan Guo ◽  
Qingxia Zhu ◽  
Wenda Wu ◽  
Yu Chen
Keyword(s):  
Bond Strength ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Glass Fiber Reinforced Polymer ◽  
Bond Slip ◽  
Ordinary Concrete ◽  
Bond Performance ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Push Out

AbstractThe article describes an experimental study on the bond–slip performance between the pultruded glass fiber-reinforced polymer (GFRP) tube and the nano-CaCO3 concrete. Taking the nano-CaCO3 concrete strength and GFRP tube thickness as primary parameters, nine specimens were designed and tested to study the influence of these parameters on the bond strength of the specimens. Besides, three specimens filled with the ordinary concrete were also tested by using the push-out tests to make comparisons with the bond performance of the specimens filled with nano-CaCO3 concrete. A total of four push-out tests were conducted on each specimen. The experimental results indicate that there are two types of axial load–slip curves for each specimen in four push-out tests. Moreover, comparison of the results of the push-out tests in the same direction shows that the bond failure load of the specimen decreases with the increase in the number of push-out tests. Based on the analysis of the test results, it is shown that the bond performance between the GFRP tube and the nano-CaCO3 concrete is better than that between the GFRP tube and the ordinary concrete. Furthermore, as the nano-CaCO3 concrete strength increases, the bond strength of the specimens decreases, indicating that the concrete strength has a negative effect on the bond strength. When the nano-CaCO3 concrete strength is relatively smaller (C20), the bond strength of the specimens decreases with the increase in the thickness of the GFRP tube. However, when the nano-CaCO3 concrete strength is relatively larger (C30 and C40), the bond strength of the specimens increases as the thickness of the GFRP tube increases.

Experimental Research on Interfacial Bond Performance in Rock Anchor with High-Performance Grouting Medium

2012 ◽  
Vol 517 ◽  
pp. 932-938 ◽  
Author(s):  
Zhi Fang ◽  
Hong Qiao Zhang
Keyword(s):  
Rock Mass ◽  
Bond Strength ◽  
High Performance ◽  
Interfacial Bond ◽  
Interfacial Bond Strength ◽  
Bond Performance ◽  
Pull Out ◽  
Steel Bar ◽  
Reactive Powder ◽  
Ground Anchor

There exist the problems such as low bond strength and bad durability in the ordinary grouting slurry of the ground anchor system at present. The high-performance grouting mediums RPC (Reactive Powder Concrete) and DSP (Densified Systems containing homogeneously arranged ultrafine Particles) would become the potential replacement of grouting medium in ground anchor resulting from their high compressive strength, durability and toughness. Based on a series of pull-out tests on ground anchors with different high-performance grouting medium of RPC and DSP , different bond length in the construction field, the bond performance on the interfaces between anchor bolt (deformed steel bar) and grouted medium as well as between grouted medium and rock mass was studied. The results indicate that the interfacial bond strength between RPC or DSP and deformed steel bolt ranges within 23-31Mpa, far greater than that (about 2-3MPa) between the ordinary cementitious grout and deformed steel bar. Even though the interfacial bond strength between the grouted medium and rock mass of limestone was not obtained in the test since the failure mode was pull-out of those steel bar rather than the interface shear failure between grouted medium and rock mass, the bond stress on the interface reached 6.2-8.38 MPa, also far greater than the bond strength (about 0.1-3MPa) between the ordinary cementitious slurry and rocks.

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