Numerical Simulation of the Interfacial Behaviour of Grouted Rockbolts in Tunnel Support Based on a Tri-Linear Bond-Slip Model

2012 ◽  
Vol 446-449 ◽  
pp. 1769-1774 ◽  
Author(s):  
Fei Fan Ren ◽  
Zhen Jun Yang ◽  
Chao Xu
Keyword(s):  
Interfacial Shear Stress ◽  
Material Model ◽  
Control Parameters ◽  
Slip Model ◽  
Interfacial Behavior ◽  
Cohesive Elements ◽  
Tunnel Support ◽  
Bond Slip ◽  
Interfacial Behaviour ◽  
Linear Material

Grouted rockbolts are widely used in tunneling excavation. However, the rockbolt design is still basically empirical, the mechanical behavior of grouted rockbolts, especially the interfacial behavior, has never been studied systematically. First of all, a tri-linear bond slip model is proposed for modeling the rockbolt interfacial behavior. Then analytical solutions to grouted rockbolt are presented on the basis of a tri-linear bond-slip model. Finally, a numerical model using Abaqus program to simulate the tunnel rockbolt is proposed. This model uses cohesive elements to simulate debonding along the anchorage interfaces, meanwhile, tabular damage variable is obtained on the basis of the damage evolution law in order to correspond with the tri-linear material model. The developed model was validated by monitored data. It was found that the model was capable of predicting accurately the interfacial shear stress distribution, load on the bolt as well as the rock movements. Therefore, this model can be used to optimize the control parameters of grouted rockbolts.

Numerical Evaluation of Splitting Performance of Prestressed Concrete Prisms With Larger Diameter Prestressing Wires

2019 ◽  
Author(s):  
Moochul Shin ◽  
Hailing Yu
Keyword(s):  
Prestressed Concrete ◽  
Structural Damage ◽  
Numerical Study ◽  
Experimental Studies ◽  
Concrete Cover ◽  
Small Scale ◽  
Slip Model ◽  
Cohesive Elements ◽  
Bond Slip ◽  
Pull Out

This numerical study focuses on evaluating the structural performance of prestressed concrete prisms with larger diameter (0.315 in) prestressing wires. More commonly used prestressing wires are the 0.209 in (5.32 mm) diameter wires for prestressed concrete crossties. However, there has been an interest to adopt larger diameter prestressing wires in order to provide higher prestress forces with the aim of mitigating the structural damage of prestressed concrete crossties. Previous experimental studies demonstrated that small-scale pretensioned concrete prisms had excellent correlation in bonding performance of concrete ties pretensioned with 0.209 in (5.32 mm) wires or three- or seven-wire strands. Using a finite element (FE) modeling approach, this study investigates the effects of 8 mm diameter prestressing wires on the splitting/bursting performance of prisms at the onset of de-tensioning of the wires. The studied parameters include geometrical/mechanical parameters such as thickness of the concrete cover, spacing between the wires, level of prestress forces, and concrete release strength in compression. Cohesive elements with a newly developed nonlinear bond-slip model are assigned to the interface between the prestressing wires and the surrounding concrete. The parameters for the bond-slip model are calibrated based on a simple pull-out test on concrete cylinders with the 0.315 in (8 mm) diameter wires. The simulation results are compared with the predicted splitting performance of prisms pretensioned with 0.209 in (5.32 mm) wires or seven-wire strands. Based on the FE analysis results, recommendations are made on the minimum concrete cover thickness and wire spacing required to achieve acceptable splitting/bursting performance in prestressed concrete prisms.

Interface Shear Stress of Concrete Beams Strengthened with FRP in Salt Water

2012 ◽  
Vol 446-449 ◽  
pp. 3499-3502
Author(s):  
Chen Zhao ◽  
Pei Yan Huang ◽  
Zhong Song Chen
Keyword(s):  
Shear Stress ◽  
Concrete Beam ◽  
Salt Water ◽  
Interfacial Shear Stress ◽  
Interfacial Properties ◽  
Interfacial Shear ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
Bond Slip ◽  
Relationship Model

Based on existing methods and results of other research, the bond-slip relationship model is given and the distrubition of shear stress of concrete beam strengthened by FRP in salt water is derived. Through a specific example to analyze the distribution of interfacial shear stress, and the different effects caused by different aggressive environment on the interfacial properties. The results show that: 1) Interfacial shear stress will sharply reduce with increasing distance from the end; 2) Different environments have different effects on the interface properties of FRP strengthened beams. Salt water erosion influnce the interfacial properties of FRP strengthened beams significantly.

A unified bond-slip model for the interface between FRP and steel

2021 ◽  
pp. 109380
Author(s):  
Cheng Jiang ◽  
Qian-Qian Yu ◽  
Xiang-Lin Gu
Keyword(s):  
Slip Model ◽  
Bond Slip

scholarly journals Experimental Study on Bond-Slip Behavior of Bamboo Bolt-Modified Slurry Interface under Pull-Out Load

2018 ◽  
Vol 2018 ◽  
pp. 1-23 ◽  
Author(s):  
Wei Lu ◽  
Dong Zhao ◽  
Xiao-fei Mao ◽  
Yu Ai
Keyword(s):  
Axial Direction ◽  
Impact Factors ◽  
Slip Model ◽  
Distribution Law ◽  
Bond Slip ◽  
Pull Out ◽  
Control Interface ◽  
Bolt Diameter ◽  
Interface Bond

This paper presents an analysis of bamboo bolt-modified slurry interfaces based on 26 in situ axial pull-out tests intended to highlight the mechanical behavior of interface under a fracture mode. Three impact factors are analyzed: anchorage length, bolt diameter, and bolt hole diameter, using the same materials of bamboo and modified slurry. The result shows that the interface between the bamboo bolt and anchoring agent is the control interface of an anchorage system, and the local behavior of the interface involves four stages: elastic, soften, friction, and decoupling. Distribution law and change trend of slippage, stress, and strain of anchoring interface along with the axial direction of an anchor bolt were analyzed. The result shows that there is effective anchoring length limit in this kind of interface, and that the complete decoupling phenomenon should not be neglected. Through a comparative analysis of the existing bond-slip model and interface bond-slip curve, and considering the correspondence of the strain-slip curve and trilinear bond-slip model simultaneously, a modified trilinear bond-slip model has been proposed. The friction section of this model is limited, and shearing stress in the complete decoupling section is zero.

Crack Calculation of Beams Reinforced with FRP Bars Based on Linear Bond-Slip Model

2014 ◽  
Vol 919-921 ◽  
pp. 1377-1380
Author(s):  
Xiao Dong Li ◽  
Hao Chen Feng ◽  
Wei Ning Yuan
Keyword(s):  
Stress Distribution ◽  
Crack Width ◽  
Bond Stress ◽  
Distribution Model ◽  
Slip Model ◽  
Bond Slip ◽  
Frp Bars

This paper mainly gets a equation of crack width calculation. To get the result, the lineared bond-slip model between FRP bars and concrete is used, combining with the bond stress distribution model which is found by You Chunan. Finally, the value of this paper is compared with the value of ACI440.1R-06 and JSCE code, which prove the result is right.

scholarly journals Influence of material models on quality of results of plastic parts’ mechanical analyses

Mechanik ◽  
2017 ◽  
Vol 90 (12) ◽  
pp. 1193-1195
Author(s):  
Przemysław Poszwa ◽  
Paweł Brzęk ◽  
Marek Szostak
Keyword(s):  
Material Model ◽  
Stress And Strain ◽  
Material Models ◽  
Quality Of Results ◽  
Nonlinear Properties ◽  
Linear Material ◽  
Plastic Parts

The influence of simplified and expanded material model on stress and strain in plastic parts was presented. Due to nonlinear properties, the prediction of plastic parts behavior is difficult. In this paper, it was shown what simplifications should be used with linear material model for fiber-filled plastics.

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