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

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.

2012 ◽  
Vol 166-169 ◽  
pp. 514-519
Author(s):  
Jian Wen Zhang ◽  
Shi Hui Guo

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.


2021 ◽  
Author(s):  
Yan Lan

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.


2021 ◽  
Author(s):  
Yan Lan

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.


1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.


2011 ◽  
Vol 287-290 ◽  
pp. 603-607
Author(s):  
Chun Lin Xia ◽  
Yang Fang Wu ◽  
Qian Qian Lu

Using domestic MFSP membrane as a medium of energy conversion, a kind of MFSP actuator was designed. The dedicated test equipment was constructed for experimental research, and the experimental results were given. The strip and circular MSFP membrane were analyzed qualitatively to obtain the deformation characteristics of membrane by finite element analysis software.


Author(s):  
Md Mohiuddin ◽  
Asma Akther ◽  
Eun Byul Jo ◽  
Hyun Chan Kim ◽  
Jaehwan Kim

The present study investigates a film actuator made with dielectric cellulose acetate films separated by narrow spacers as a means of electrostatic actuation for potential haptic application. Fabrication process for the actuator is explained along with experiments conducted over a wide frequency range of actuation frequency. A valid finite element simulation of the actuator is made on the quarter section of the actuator by using full 3D finite elements. Vibration characteristics such as fundamental natural frequency, mode shape and output velocity in the frequency range for haptic feeling generation are obtained from the finite element analysis and compared with the experimental results. Experimental results demonstrate that the finite element model is practical and effective enough in predicting the vibration characteristics of the actuator for haptic application. The film actuator shows many promising properties like high transparency, wide range of actuation frequency and high vibration velocity for instance.


Author(s):  
Ajay Garg

Abstract In high pressure applications, rectangular blocks of steel are used instead of cylinders as pressure vessels. Bores are drilled in these blocks for fluid flow. Intersecting bores with axes normal to each other and of almost equal diameters, produce stresses which can be many times higher than the internal pressure. Experimental results for the magnitude of maximum tensile stress along the intersection contour were available. A parametric finite element model simulated the experimental set up, followed by correlation between finite element analysis and experimental results. Finally, empirical methods are applied to generate models for the maximum tensile stress σ11 at cross bores of open and close ended blocks. Results from finite element analysis and empirical methods are further matched. Design optimization of cross bores is discussed.


2014 ◽  
Vol 580-583 ◽  
pp. 2134-2140
Author(s):  
Jian Zhang ◽  
Jian Feng Zhai ◽  
Xian Mei Wang ◽  
Jie Chen

Two-Dimensional finite element analysis was used to investigate the performance of seawall construction over weak subgrade soil using artificial base layer material consisted of cemented sand cushion comprising geosynthetics materials. Two types of base layer materials pure sand and cemented sand comprising husk rich ash and two types of geosynthetics materials geogrid and geotextile were used. Constitutive models were used to represent different materials in numerical analysis. The competence of two-dimensional numerical analysis was compared with experimental results. Numerical results showed a superior harmony with the experimental results. Finite element analysis model proved to be a great tool to determine the parameters that are difficult to measure in laboratory experiments. In addition, finite element analysis has the benefit of cost and time saving when compared to experimental investigation work. Numerical results showed strain induced in geosynthetics eliminated beyond a distance approximately equal six times of footing width.


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