Effect of loading rate on the bond behavior of plain round bars in concrete under lateral pressure

Li, Xinxin; Wu, Zhimin; Zheng, Jianjun; Dong, Wei

doi:10.1016/j.conbuildmat.2015.07.085

Cited by 20 publications

(11 citation statements)

References 14 publications

(21 reference statements)

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“…For the case without transverse stresses, the DIF of τ p is around 1.0, similar to that of straight steel fibers, 42,43 in which the bond strength is also provided by adhesion and friction 44 . When transverse tensile‐compressive stresses are applied, the DIF of τ p increases linearly as p c increases, which is in agreement with the conclusion of Li et al 35 . In their study, the uniaxial transverse pressure varying from 0 to 0.6 f cu with an increment of 0.1 f cu was adopted but the strain rate range was the same.…”

Section: Experimental Results and Analysissupporting

confidence: 87%

“…The reason for this is that, when a transverse pressure is applied, τ p is mainly contributed by the friction at the smooth bar‐concrete interface, which is dependent on the coefficient of friction of the interface and the normal stress acting on the smooth bar. As the strain rate increases, the coefficient of friction of the interface increases 35,41 . Although the smooth bar contracts in the radial direction due to the Poisson effect during the pull‐out process, the bar‐concrete interface is compacted under the transverse pressure and τ p is improved.…”

Section: Experimental Results and Analysismentioning

confidence: 99%

“…The rate dependence of τ p was found to be proportional to the applied transverse pressure. Therefore, the DIF of τ p for the cases with uniaxial transverse pressure in Li et al 35 (test groups N1–N28 and N53–N79) is calculated and used to calibrate the model of DIF of τ p , which is given by Equation () with a correlation coefficient of 0.73.

\frac{τ_{p, dyn}}{τ_{p, sta}} = 1.0 + 0.1 \frac{p_{c}}{f_{italiccu}} \log ((), \frac{\overset{γ}{true}}{{\dot{γ}}_{0}}) for \frac{p_{c}}{f_{italiccu}} = \frac{p_{t}}{f_{t}} = 0, or 0 < \frac{p_{c}}{f_{italiccu}} \leq 0.6, 0 < \frac{p_{t}}{f_{t}} \leq 0.6, \frac{p_{c}}{f_{italiccu}} + \frac{p_{t}}{f_{t}} \leq 0.8

…”

Section: Experimental Results and Analysismentioning

confidence: 99%

“…As a result, it is impossible to investigate the bond degradation of smooth bars or to establish a complete τ ‐ s model. Li et al 35 studied the dynamic bond behavior of smooth bars in concrete subjected to transverse pressure and proposed a dynamic τ ‐ s model. Subsequently, Li et al 36 adopted the modified BPE model to describe the dynamic bond behavior of smooth bars under transverse tension.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic bond stress‐slip model for smooth bars in concrete under transverse tensile‐compressive stresses

Zheng

2021

Structural Concrete

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Most old‐type reinforced concrete (RC) buildings reinforced with smooth bars are often subjected to dynamic loads and the structural joints are usually in a complex tensile‐compressive stress state. To evaluate the safety and durability of RC structures with the finite element method, the dynamic bond performance of smooth bars in concrete under transverse tensile‐compressive stresses needs to be well understood. Therefore, an experimental study including 248 pull‐out specimens is performed to characterize the dynamic bond properties of smooth bars in concrete under transverse tensile‐compressive stresses. Based on the experimental results and other data, the effects of various factors on the peak bond stress, the slip at the peak bond stress, and the shape of the softening branch are analyzed in detail. With two bond parameters and one shape parameter, a simple bond stress‐slip model is proposed. Through comparison with experimental results, the validity of the model is verified.

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Section: Experimental Results and Analysissupporting

confidence: 87%

Section: Experimental Results and Analysismentioning

confidence: 99%

\frac{τ_{p, dyn}}{τ_{p, sta}} = 1.0 + 0.1 \frac{p_{c}}{f_{italiccu}} \log ((), \frac{\overset{γ}{true}}{{\dot{γ}}_{0}}) for \frac{p_{c}}{f_{italiccu}} = \frac{p_{t}}{f_{t}} = 0, or 0 < \frac{p_{c}}{f_{italiccu}} \leq 0.6, 0 < \frac{p_{t}}{f_{t}} \leq 0.6, \frac{p_{c}}{f_{italiccu}} + \frac{p_{t}}{f_{t}} \leq 0.8

…”

Section: Experimental Results and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic bond stress‐slip model for smooth bars in concrete under transverse tensile‐compressive stresses

Zheng

2021

Structural Concrete

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“…Previous studies of GFRP reinforced concrete components mainly focused on a series of problems, such as low toughness and bond behavior, short‐ and long‐term durability, freeze–thaw performance, fire resistance and cracking resistance . In recent years, researchers have been considering the factors that affect the bond performance of GFRP bar‐reinforced concrete at different loads and their coupling conditions, including high and low temperature, freeze–thaw cycles, sustained load, fatigue load, cyclic loading, and loading rate . The application of the sustained load, lower than the maximum, after a process of unloading and reloading, causes an “immediate” deflection after cycling larger than that corresponding to the same load in the initial monotonic loading .…”

Section: Introductionmentioning

confidence: 99%

Bond‐Slip Behavior Between GFRP Bars and Mortar Based on Pull‐Out Tests

et al. 2018

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Bond performance is important in glass fiber reinforcement polymer (GFRP) bar reinforced mortar structure. To study bond behavior between GFRP bars and mortar, pull‐out tests were conducted on nine cylinder specimens with reinforced carbon sheets. The loading mode included monotonic loading and cyclic loading. Bond strength, slip, bond stiffness, and residual bond properties were investigated and fitted to bond‐slip curves of classical models. The results show that monotonic loading, cyclic constant loading, and cyclic variable loading have little effect on the ultimate bond strength between a GFRP bar and mortar. The bond‐slip curves have the same change laws. Under cyclic constant loading, bond stiffness increases with cycles loading times and is basically stable after 10 times, and the bond‐slip curves show the same characteristics. Under cyclic variable loading, bond stress–strain has a linear characteristic, bond stiffness presents a hardening tendency, and bond‐slip curve is similar and stable in each loading–unloading process. The ascending stage and descending stage of the bond‐slip curve match the modified Eligehausen, Popov, and Bertero (mBPE) model, no horizontal line is observed in the peak load stage, the descending stage curve is approximately linear, and the residual stage curve exhibits a fluctuating decreasing tendency. Based on the test results, a Gaussian function and its parameters are proposed for the expression of the residual stage. POLYM. COMPOS., 40:2840–2849, 2019. © 2018 Society of Plastics Engineers

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