Mesoscale modelling of bond performance between deformed steel bar and concrete subjected to dynamic loads

2022 ◽  
pp. 104159
Author(s):  
Renbo ZHANG ◽  
Liu JIN ◽  
Mengjia LIU ◽  
Xiuli DU ◽  
Jingbo LIU
Keyword(s):  
Dynamic Loads ◽  
Mesoscale Modelling ◽  
Bond Performance ◽  
Steel Bar

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.

Bond performance of GFRP and deformed steel hybrid bar with sand coating to concrete

2016 ◽  
Vol 36 (6) ◽  
pp. 464-475 ◽  
Author(s):  
Minkwan Ju ◽  
Gitae Park ◽  
Sangyun Lee ◽  
Cheolwoo Park
Keyword(s):  
Glass Fiber ◽  
Modulus Of Elasticity ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Bond Performance ◽  
Polymer Hybrid ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Steel Bar

In this study, we experimentally investigated the bond performance of a glass fiber-reinforced polymer hybrid bar with a core section comprising a deformed steel bar and a sand coating. The glass fiber-reinforced polymer and deformed steel hybrid bar (glass fiber-reinforced polymer hybrid bar) can contribute to longer durability and better serviceability of reinforced concrete members because of the increased modulus of elasticity provided by the deformed steel bar. Uniaxial tensile tests in compliance with ASTM D 3916 showed that the modulus of elasticity of the glass fiber-reinforced polymer hybrid bar was enhanced up to three times. For the bond test, a total of 30 specimens with various sand-coating and surface design parameters such as the size of the sand particles (0.6 mm and 0.3 mm), sand-coating type (partially or completely), number of strands of fiber ribs (6 and 10), and pitch space (11.4 mm to 29.1 mm) of the fiber ribs were tested. The completely sand-coated glass fiber-reinforced polymer hybrid bar exhibited a higher bond strength (90.5%) than the deformed steel bar and a reasonable mode of failure in concrete splitting. A modification parameter to the Eligehausen, Popov, and Bertero (BPE) model is suggested based on the representative experimental tests. The bond stress–slip behavior suggested by the modified BPE model in this study was in reasonable agreement with the experimental results.

scholarly journals Bond Effects between Concrete and Steel Bar Using Different Diameter Bars and Different Initial Crack Width

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Papa Niane Faye ◽  
Yinghua Ye ◽  
Bo Diao
Keyword(s):  
Crack Width ◽  
Chloride Content ◽  
Initial Crack ◽  
Bond Performance ◽  
Pull Out ◽  
Steel Bar ◽  
Service Conditions ◽  
Concrete Casting ◽  
Initial Cracks ◽  
Bar Diameter

The importance of an accurate simulation of service conditions in the bond performance of reinforced concrete structures in coastal regions is highlighted. Four widths of initial crack of 0, 80, 150, and 210 microns were artificially made by inserting slice into bond specimens during concrete casting. Three bar diameters of 10 mm, 14 mm, and 18 mm were selected. At 28 days, the bond specimens were exposed to the environment of wet-dry cycles of seawater and atmosphere for another 90 days. The pull-out test was then conducted and chloride contents were tested at crack area along 40 mm depth. Results show that, for the specimen with 10 mm bar diameter, cracks width of less than 80 microns vanished rapidly during wet-dry cycles; for other specimens, cracks width of 100–150 microns decreased slightly. However the cracks of width more than 200 microns increased gradually; the chloride content decreased along the depth of concrete, and the chloride content increased as the widths of initial cracks increased or as the bar diameters increased. The ductility of bond specimens decreased as the diameter increased.

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.

Effect of Electrochemical Chloride Extraction on the Bond Performance between Steel Bar and Concrete

2011 ◽  
Vol 243-249 ◽  
pp. 5536-5540 ◽  
Author(s):  
Yu Xia Guo ◽  
Jing Xing Gong
Keyword(s):  
Bond Strength ◽  
Current Density ◽  
Bond Performance ◽  
Steel Bar ◽  
Initial Content ◽  
Electrochemical Chloride Extraction ◽  
Electric Quantity

Based on beam specimens of 100mm×100mm×400mm, the effect of electrochemical chloride extraction (ECE) on bond performance between steel bar and concrete contaminated by chloride was studied by determining the bond strength of them. During the test, 1%, 2% and 3% NaCl by weight of cement were mixed into concrete to simulate chloride contamination. In the process of ECE, four kinds of current density (1, 2, 3, 5 A/m2of steel bar area) and electric quantity (500, 1000, 1500 and 3000 A.h/m2of steel bar area) were taken into account, respectively. It is indicated that the bond strength between steel bar and concrete was degraded after ECE treatment, the more the current and the electric quantity of ECE are, the more the loss of bond strength is, and the initial content of chloride in concrete has a little influence on the bond strength.

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.

scholarly journals Mesoscale modelling of bond failure behavior of ribbed steel bar and concrete interface

2019 ◽  
Vol 49 (4) ◽  
pp. 445-454
Author(s):  
Liu JIN ◽  
MengJia LIU ◽  
JingQi HUANG ◽  
XiuLi DU
Keyword(s):  
Failure Behavior ◽  
Mesoscale Modelling ◽  
Bond Failure ◽  
Steel Bar ◽  
Concrete Interface

Bond Performance of Steel Bar in RAC under Salt-Frost and Repeated Loading

2020 ◽  
Vol 32 (9) ◽  
pp. 04020261
Author(s):  
Tian Su ◽  
Jin Wu ◽  
Zhenghao Zou ◽  
Jifeng Yuan
Keyword(s):  
Repeated Loading ◽  
Bond Performance ◽  
Steel Bar

Study of the dynamics of ТПА 350 automatic mill working stand elements

2020 ◽  
Vol 76 (8) ◽  
pp. 830-840
Author(s):  
S. R. Rakhmanov ◽  
V. V. Povorotnii
Keyword(s):  
Mechanical System ◽  
Dynamic Model ◽  
Maximum Amplitude ◽  
Calculation Scheme ◽  
Dynamic Loads ◽  
Forced Oscillations ◽  
Mass Model ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Oscillation Movement

To form a necessary geometry of a hollow billet to be rolled at a pipe rolling line, stable dynamics of the base equipment of the automatic mill working stand has a practical meaning. Among the forces, acting on its parts and elements, significant by value short-time dynamic loads are the least studied phenomena. These dynamic loads arise during transient interaction of the hollow billet, rollers, mandrel and other mill parts at the forced grip of the hollow billet. Basing of the calculation scheme and dynamic model of the mechanical system of the ТПА 350 automatic mill working stand was accomplished. A mathematical model of dynamics of the system “hollow billet (pipe) – working stand” within accepted calculation scheme and dynamic model of the mechanical system elaborated. Influence of technological load of the rolled hollow billet variation in time was accounted, as well as variation of the mechanical system mass, and rigidity of the ТПА 350 automatic mill working stand. Differential equations of oscillation movement for four-mass model of forked sub-systems of the automatic mill working stand were made up, results of their digital calculation quoted. Dynamic displacement of the stand elements in the inter-roller gap obtained, which enabled to estimate the results of amplitude and frequency characteristics of the branches of the mill rollers setting. It was defined by calculation, that the maximum amplitude of the forced oscillations of elements of the ТПА 350 automatic mill working stand within the inter-roller gap does not exceed 2 mm. It is much higher than the accepted value of adjusting parameters of the deformation center of the ТПА 350 automatic mill. A scheme of comprehensive modernization of the rollers setting in the ТПА 350 automatic mill working stand was proposed. It was shown, that increase of rigidity of rollers setting in the ТПА 350 automatic mill working stand enables to stabilize the amplitude of forced oscillations of the working stand elements within the inter-rollers gap and considerably decrease the induced nonuniform hollow billet wall thickness and increase quality of the rolled pipes at ТПА 350.

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