scholarly journals Experimental and Numerical Investigation of Bond-Slip Behavior of High-Strength Reinforced Concrete at Service Load

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 293
Author(s):  
Alinda Dey ◽  
Domas Valiukas ◽  
Ronaldas Jakubovskis ◽  
Aleksandr Sokolov ◽  
Gintaris Kaklauskas
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Numerical Investigation ◽  
Load Level ◽  
Scale Model ◽  
Element Analysis ◽  
Bond Slip ◽  
Pull Out ◽  
Bond Mechanism ◽  
Concrete Interface

A bond mechanism at the reinforcement-concrete interface is one of the key sources of the comprehensive functioning of reinforced concrete (RC) structures. In order to apprehend the bond mechanism, the study on bond stress and slip relation (henceforth referred as bond-slip) is necessary. On this subject, experimental and numerical investigations were performed on short RC tensile specimens. A double pull-out test with pre-installed electrical strain gauge sensors inside the modified embedded rebar was performed in the experimental part. Numerically, a three dimensional rib scale model was designed and finite element analysis was performed. The compatibility and reliability of the numerical model was verified by comparing its strain result with an experimentally obtained one. Afterwards, based on stress transfer approach, the bond-slip relations were calculated from the extracted strain results. The maximum disparity between experimental and numerical investigation was found as 19.5% in case of strain data and 7% for the bond-slip relation at the highest load level (110 kN). Moreover, the bond-slip curves at different load levels were compared with the bond-slip model established in CEB-fib Model Code 2010 (MC2010). Overall, in the present study, strain monitoring through the experimental tool and finite element modelling have accomplished a broader picture of the bond mechanism at the reinforcement-concrete interface through their bond-slip relationship.

scholarly journals Analytical modeling of the contact pressure at the steel-concrete interface

2021 ◽  
Author(s):  
Sini Bhaskar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Contact Pressure ◽  
Analytical Model ◽  
Concrete Member ◽  
Element Analysis ◽  
Pull Out ◽  
Reinforced Concrete Member ◽  
Concrete Interface

This research studies the effect of corrosion on bond strength at the steel-concrete interface in a reinforced concrete member. Bond stress, which can be defined as the shear stress which develops along the lateral surface of the bar, is expressed as a function of contact pressure at the steel-concrete interface. An analytical model of bond which describes the contact pressure between the reinforcing bar and concrete in a reinforced concrete member is developed. The expression for the reduction in contact pressure due to the accumulation of corrosion products is then developed using the model developed for the uncorroded reinforcing steel bar. The developed analytical model was implemented in a finite element analysis, which was conducted using ABAQUS, of pull-out specimens conducted by Amleh (2000). A reasonable good agreement between the experimental and finite element analysis results was obtained.

scholarly journals Analytical modeling of the contact pressure at the steel-concrete interface

2021 ◽  
Author(s):  
Sini Bhaskar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Contact Pressure ◽  
Analytical Model ◽  
Concrete Member ◽  
Element Analysis ◽  
Pull Out ◽  
Reinforced Concrete Member ◽  
Concrete Interface

This research studies the effect of corrosion on bond strength at the steel-concrete interface in a reinforced concrete member. Bond stress, which can be defined as the shear stress which develops along the lateral surface of the bar, is expressed as a function of contact pressure at the steel-concrete interface. An analytical model of bond which describes the contact pressure between the reinforcing bar and concrete in a reinforced concrete member is developed. The expression for the reduction in contact pressure due to the accumulation of corrosion products is then developed using the model developed for the uncorroded reinforcing steel bar. The developed analytical model was implemented in a finite element analysis, which was conducted using ABAQUS, of pull-out specimens conducted by Amleh (2000). A reasonable good agreement between the experimental and finite element analysis results was obtained.

Finite Element Analysis of the Pull-Out Specimens of Steel Reinforced Lightweight Concrete

2012 ◽  
Vol 166-169 ◽  
pp. 514-519
Author(s):  
Jian Wen Zhang ◽  
Shi Hui Guo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Lightweight Concrete ◽  
Constitutive Relationship ◽  
Test Results ◽  
Concrete Element ◽  
Element Analysis ◽  
Bond Slip ◽  
Spring Element ◽  
Pull Out

Finite element analysis method of steel reinforced lightweight concrete pull-out specimens is exploded based on the test results. Spring element and local bond slip constitutive relation are introduced in analysis so as to consider the interfacial bond-slip between steel and lightweight concrete. Element tributary area and flange or web position should be taken into account in order to confirm the spring element real constant. Analysis results indicate that specimens bearing capacity and deformation can be well simulated adopting the stated method and constitutive relationship.

scholarly journals Bond Behavior of Reinforced Concrete Considering Freeze–Thaw Cycles and Corrosion of Stirrups

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4732
Author(s):  
Shuo Liu ◽  
Maohua Du ◽  
Yubin Tian ◽  
Xuanang Wang ◽  
Guorui Sun
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Bond Strength ◽  
Mechanical Performance ◽  
Element Analysis ◽  
Freeze Thaw ◽  
Bonding Performance ◽  
Pull Out ◽  
Steel Bar

In relatively cold environments, the combination of freeze–thaw and steel bar corrosion is a key factor affecting the durability of concrete. The adjustment of the stirrup ratio would change the mechanical performance of surrounding concrete, while the circumferential compressive stress can further improve the bonding performance. Hence, based on eccentrically tensioned specimens, the influence of corrosion of stirrups and freeze–thaw of concrete on bond properties is discussed in this paper. The monotonic pull-out test of reinforced concrete specimens is carried out to study the variation rules of bond strength and slip between steel bar and concrete under the coupling action of corrosion rate, freeze–thaw times and stirrup spacing. Based on the experimental data, the empirical formula for the ultimate bond strength is obtained, and a bond–slip constitutive model is established considering the stirrup spacing, stirrup corrosion rate and freeze–thaw times. Then, a refined finite element pull-out specimen model is established by ABAQUS simulation, and the numerical simulation results are compared with the real test ones, so as to make up for the deficiencies in the test and lay the foundation for further finite element analysis.

scholarly journals Finite Element Analysis of Corrosion and Bond-Slip

2021 ◽  
Author(s):  
Yan Lan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforcement Corrosion ◽  
Element Analysis ◽  
Rc Structures ◽  
Bond Slip ◽  
Linear Finite Element ◽  
Rc Structure ◽  
Non Linear ◽  
Bond Mechanism

Although reinforced concrete (RC) has an important advantage that it has virtue durability against an environmental attack, especially the resistance of corrosion of embedded reinforcements, due to the high alkalinity nature of concrete property, unfortunately, the problems of reinforcement corrosion still exist in many reinforced concrete structures. It has brought out many questions on the safety and serviceability of these corroded RC structures. Thus, it needs more effective approach for structural performance evaluation of the corroded structures. The residual capacity of the corroded reinforcement was determined through the evaluation of the volume increase of reinforcing steel and concrete crack propagation. The final determination of the service life of concrete structures was made based on the above evaluation results. Also, the effects of reinforcement corrosion on structural behaviours of RC members are investigated so that the reliable evaluation of structural performances of corroded RC members can be achieved by finite element method (FEM). The corrosion attack penetration has been given as a function of the time as input in the analyses. The load of corrosion applied inside the structural members can be modelled by the displacement around the circumferential surface between the reinforcing bars and concrete. The reduction of capability of the structures is determined from the corrosion level in the service years. Another complex phenomenon that governs concrete behaviour is the transfer of shear force across the interface by bond mechanism between concrete and steel reinforcement. It is a fundamental to most aspects of concrete behaviour. The bond mechanism is influenced by multiple parameters, such as the strength of the surrounding structures, the occurrence of splitting cracks in the concrete and the yielding of the reinforcement. However, when RC structures are analysed using the FEM, it is quite common to assume that the bond stress depends solely on the slip between the bars and concrete. In this the research the relationship of bond slip is also studied using FEM. An analytical study based on fracture mechanics was earned out to investigate the behaviour of three different types of specimens. In recent RC research, finite element modelling techniques have been developed to quickly evaluate the physical phenomena associated with cracking and bond. The non-linear finite element program ATENA with the non-linear material models for concrete, reinforcement bar and bond-slip is used to analyse cracking propagation and bond failure process. The influence between corrosion and bond slip in RC structure is also studied. Therefore, the understanding of serviceability of RC structure is improved. It was concluded that with the increase of load and the propagation of the crack, stress redistributed in the steel- continues until the specimen is damaged. The non-linear finite element fracture analysis shows that non-linear fracture mechanics can be effectively applied to investigate concrete fracture. Also, comparisons between the analyses of crack propagation and stress redistribution obtained using the finite element analysis was in good agreement with tests found in the literature.

Advanced Simulations for Seismic Design of Reinforced Concrete Joints

2019 ◽  
Author(s):  
Roberto T. leon ◽  
Ioannis Koutromanos ◽  
Chenxi Xing
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Resistance Mechanisms ◽  
Element Formulation ◽  
Moment Frames ◽  
Design Standards ◽  
Element Analysis ◽  
Bond Slip ◽  
Shear Cracking ◽  
Concrete Joints

<p>The seismic performance of older reinforced concrete moment frames in recent earthquakes indicates that these buildings are particularly vulnerable to collapse. Although extensive experimental research over the last three decades has clarified some of the mechanisms governing the behavior of this structural typology, detailed modeling of their behavior has remained elusive. A primary reason is that our ability to model the beam-column-slab connections is poor when shear cracking and bond degradation interact strongly. In this work, two types of advanced models have been developed to address this shortcoming: one based on a refined finite element analysis and one on a simplified truss analogy. In both cases, the intent is to elucidate the resistance mechanisms, peak strength, bond behavior and ductility exhibited by beam column joints. In the finite element formulation, superior results are obtained through careful material modeling, including the bond-slip relationship. The simplified model uses a nonlinear truss analogy, with the bond-slip effect accounted for through nonlinear zero-length spring elements with appropriate constitutive relationships. Both models are calibrated to well-documented tests and are shown to produce very good results when comparing local measurements. The truss model actually produces better results for cases where shear cracking dominates the overall behavior. The models are used to assess the performance of prototype connections designed to meet current American design standards. The results indicate that these joints will perform as expected under uniaxial cyclic loads, with strength and stiffness deterioration beginning around 3% drift. Further studies, not described herein, have shown very poor joint performance if subjected to biaxial loads and poorly if subjected to large cyclic deformations.</p>

scholarly journals TENSION STIFFENING BOND MODELLING OF CRACKED FLEXURAL REINFORCED CONCRETE BEAMS/SUPLEIŠĖJUSIŲ GELŽBETONINIŲ SIJŲ ARMATŪROS IR BETONO SANKIBOS MODELIAVIMAS

2008 ◽  
Vol 14 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Salah Khalfallah
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Numerical Approach ◽  
Reinforced Concrete Beams ◽  
Reinforcing Bars ◽  
Transfer Length ◽  
Element Analysis ◽  
Bond Slip ◽  
Pull Out ◽  
Non Linear

This paper deals with the analysis of cracked flexural reinforced concrete structures with special highlighting of modelling the interaction between concrete and reinforcement. A new approach based on the bond stress distribution through the transfer length between the zero‐slip and the cracked sections is proposed. Since the cracking phenomenon of concrete occurs, the fracture energy changes in order to appeal to the interaction between concrete and steel. The increment of stresses is evaluated by the bond‐slip distribution by means of one‐dimensional problem. Besides, the 2D nonlinear description of components behaviour, concrete and steel are considered. On numerical modelling level, the interaction property is obtained from a variety of fundamental pull out and push out tests, for the most part this phenomenon does not very well represent the bending members. For this object, this study presents a numerical approach, which can compute the distribution stresses at the steel‐concrete interface near flexural crack in reinforced concrete beams. Finally, predictions made by the non‐linear finite element analysis program and the non‐linear material models for concrete, reinforcing bars and bond slip are in good agreement with the experimental results. Santrauka Straipsnyje atlikta supleišėjusių lenkiamųjų gelžbetoninių elementų analizė armatūros ir betono sąveikos modeliavimo aspektu. Pasiūlytas naujas modelis, pagrįstas sukibimo įtempių pasiskirstymu sąveikos zonos ilgiu nuo nulinio praslydimo iki plyšio pjūvio. Supleišėjus betonui dėl jo sąveikos su armatūra keičiasi irimo energija. Įtempių didėjimas sukibimo ir praslydimo zonoje įvertinamas taikant vienmatį (1D) modelį. Sąveikos komponentų (betono ir armatūros) elgsena aprašoma pasitelkiant dvimačius (2D) modelius. Atliekant skaitinį modeliavimą, betono ir armatūros sąveikos parametrai dažniausiai nustatomi pagal klasikinius ištraukimo ir išstūmimo bandymus. Tačiau lenkiamiesiems elementams taip nustatyti parametrai netinka. Pasiūlytas skaitinis supleišėjusių lenkiamų gelžbetoninių sijų skaičiavimo algoritmas, kurį taikant gali būti nustatytas įtempių pasiskirstymas plieno ir betono sąveikos paviršiuje pjūvyje ties plyšiu. Skaičiavimo rezultatai, gauti taikant netiesinės analizės baigtinių elementų programą kartu su betono, armatūros ir sankibos modeliais, gerai sutapo su eksperimentinių tyrimų rezultatais.

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.

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