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.

Bond of Steel Bars to Masonry Mortar Joints: Test Results and Analytical Modelling

2017 ◽  
Vol 747 ◽  
pp. 319-325 ◽  
Author(s):  
Matteo Maragna ◽  
Cristina Gentilini ◽  
Giovanni Castellazzi ◽  
Christian Carloni
Keyword(s):  
High Strength ◽  
Experimental Tests ◽  
Analytical Investigation ◽  
Masonry Walls ◽  
Test Results ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bars ◽  
Masonry Mortar

In this paper, the preliminary results of a series of pull-out tests conducted on mortar cylinders with embedded bars are presented. The bars are made of high strength stainless steel and are of helical shape to increase mechanical interlocking with the surrounding mortar. Usually, such bars are employed in situ to realize structural repointing in the case of fair-faced masonry walls. To this aim, they are inserted in the mortar bed joints of masonry for providing tensile strength to the walls and with the function of crack stitching. The aim of the present experimental tests is to determine the bond-slip relationship for bars embedded in masonry. Firstly, pull-out tests are conducted on mortar cylinders considering different embedded lengths of the bars. Further tests are on-going on masonry specimens with bars embedded in the mortar joints. An analytical investigation is also carried out for the interpretation of the pull-out test results.

Fractal Analysis on Bond-Slip Behavior between Steel Shape and Concrete in SRC on Axial Pull-Out Test

2011 ◽  
Vol 382 ◽  
pp. 352-355 ◽  
Author(s):  
Ming Xie ◽  
Shan Suo Zheng
Keyword(s):  
Fractal Dimension ◽  
Composite Structures ◽  
Impact Factors ◽  
Dependence Relation ◽  
Bond Slip ◽  
Steel Reinforced Concrete ◽  
Pull Out ◽  
Steel Shape ◽  
Damage Process ◽  
The Impact

Based on the experimental study of pull-out specimens on bond-slip behaviors between shaped steel and concrete in SRC (Steel Reinforced Concrete Structures), the graphic of the whole damage process are obtained. The crack propagation of concrete is fractal analyzed to calculate the fractal dimension. Relationships between fractal dimension and bond-slip behaviors of SRC are discussed. The main factors impact the bond-slip behaviors are studied to established the relationship with fractal dimension. Linear dependence relation of fractal dimension and bond-slip behaviors and the impact factors is discovered. Statistics formula is established to describe the relation of fractal dimension and ultimate bond strengths. All these may contribute to the further analysis of bond-slip performance and fractal behaviors in SRC composite structures.

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.

Experimental Analysis of Interface Bond-Slip Relations between the Concrete and Fiber Plasterboard

2011 ◽  
Vol 255-260 ◽  
pp. 3129-3132
Author(s):  
Xin Liang Jiang ◽  
Quan Bin Zhao
Keyword(s):  
Concrete Strength ◽  
Constitutive Relationship ◽  
Analytical Models ◽  
Concrete Frames ◽  
Interfacial Bond Strength ◽  
Bond Slip ◽  
Pull Out ◽  
Core Column ◽  
Interface Length ◽  
Interface Bond

The study on bond-slip performance at the interface of concrete frames-fiber plasterboard (CFFP) is very significant to perfect the theory of CFFP and the FEM analytical models. The pull-out experiment on eight CFFP from three series does research on the effect of concrete strength and the interface length on the interfacial bond strength of fiber plasterboard and core column concrete. The experiment of CFFP is well-designed to obtain the curve of bond-slip constitutive relationship.

A Normalized Stress of Pull-Out Action on Bolted Joints Under Eccentric Load

2018 ◽  
Author(s):  
Makoto Imura ◽  
Takayuki Koyama ◽  
Motonobu Iizuka ◽  
Takayuki Suzuki
Keyword(s):  
Axial Direction ◽  
Bolted Joints ◽  
Eccentric Load ◽  
Stress Evaluation ◽  
Centrifugal Load ◽  
Pull Out ◽  
Bolt Preload ◽  
Structural Interface ◽  
Bolt Stress ◽  
Bolt Diameter

Our objective is to evaluate precisely a life-cycle of bolted joints under an eccentric load against a bolt axis. Many approaches to achieve the objective based on a lot of theories and practices have been proposed so far [1–12]. As we can refer from their approaches, the opening of the structural interface between clamped plates of bolted joints occurs by the eccentric load, which is over a bolt preload, and then the opening gradually propagates as the eccentric load increases. In the case, nonlinearity appears remarkably on the tensional and bending stress of bolts in the axial direction. In addition to the above, the axial bolt stress larger than expected occurs due to the principle of leverage depending on the load position and the bolted joints layout in the early phase of the pull-out action. Accordingly, the stress evaluation of bolted joints under the eccentric load is very important in order to ensure the safety of industrial machines. If dimensionless quantities of the bolt stress are found out considering the influence of the structural opening and the load eccentricity, we can have a few advantages as follows. First, bolt stress evaluations can be conducted by easily converting the dimensionless quantities of the bolt stress to the physical dimension quantities in a lot of cases where the bolt preload and the load eccentricity are different. Second, the number of times of verification tests can be reduced. We are developing a lot of industrial machines which have bolted joints used under eccentric load. In such development [13], bolt stress analyses are usually conducted under the combinations of the following conditions: (i) tapped thread joints, (ii) thin clamped plates than the bolt diameter, (iii) large eccentric loads, (iv) permitting the opening of the structural interface. Therefore, we propose a concept of a normalized bolt stress considering the effect of the structural opening and the load eccentricity. We validated this concept through theoretical studies, finite element analyses, and experiments under the direct load and the centrifugal load. As a result, the dimensionless quantities of the bolt stress caused by the bolt preload and a lever ratio of bolted joints under combined conditions was determined in this study. We can easily evaluate the bolt stress by simple conversions in a lot of cases in which the bolt preload and the load eccentricity differ.

In Situ Transformed Carbon Fibers/Al2O3 Nanocomposites Using Cao–MgO–SiO2 Sintering Agent

2021 ◽  
Vol 21 (10) ◽  
pp. 5235-5240
Author(s):  
Hua-Hui Chen ◽  
Jing-Jing Cao ◽  
Hai-Ping Hong ◽  
Nan Zheng ◽  
Jie Ren ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Axial Direction ◽  
Diffraction Peak ◽  
Sintering Process ◽  
Interface Bonding ◽  
The Core ◽  
Matrix Nanocomposites ◽  
Pan Fibers ◽  
Properties Of Composites

In Situ transformed carbon fibers/Al2O3 ceramic matrix nanocomposites with Cao–MgO–SiO2 sintering agent were prepared by hot-pressed sintering technology in vacuum. In the sintering process, pre-oxidized polyacrylonitrile fibers (below named as pre-oxidized PAN fibers) were used as the precursors of In Situ transformed carbon fibers. The micro/nanostructure of composites and interface between In Situ transformed carbon fibers and matrix were investigated, as well as the properties of composites. The results showed that the composites could be sintered well at a relatively low temperature of 1650 °C. During the sintering, the precursors, pre-oxidized PAN fibers, were In Situ transformed into carbon fibers, and the In Situ transformed carbon fibers had the graphitelike structure along the fiber axial direction. The carbon atoms arrangement in the surface layer of the fiber was more orderly than the core. A typical diffraction peak of carbon fiber at 26°, which corresponded to the (002) crystal plane, was observed, and the inter-planar spacing was approximately 0.34 nm. The CaO–MgO–SiO2 sintering agent formed MgAl2O4 and CaAl2Si2O8 phases in the interface between In Situ transformed carbon fibers and matrix, therefore improving the interface bonding, and thereby modifying the mechanical properties of the composites.

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

Bond behaviour of chemically prestressed textile reinforced concrete

2019 ◽  
Author(s):  
Katarzyna Zdanowicz ◽  
Boso Schmidt ◽  
Hubert Naraniecki ◽  
Steffen Marx
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Crack Width ◽  
Research Programme ◽  
Textile Reinforced Concrete ◽  
Self Compacting Concrete ◽  
Bond Behaviour ◽  
Bond Slip ◽  
Laser Sensors ◽  
Pull Out

<p>The bond behaviour of concrete specimens with carbon textile reinforcement was investigated in the presented research programme. Pull-out specimens were cast from self-compacting concrete with expansive admixtures and in this way chemical prestress was introduced. The aim of the research was to compare bond behaviour between prestressed specimens and non-prestressed control specimens. During pull-out tests, the pull-out force and notch opening were measured with a load cell and laser sensors. Further, bond - slip and pull-out force - crack width relationships were drawn and compared for prestressed and non-prestressed specimens. Chemically prestressed specimens reached 24% higher bond strength than non-prestressed ones. It can be therefore concluded, that chemical prestressing positively influences the bond behaviour of concrete with textile reinforcement and thus better utilisation of its properties can be provided.</p>

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

2018 ◽  
Vol 40 (7) ◽  
pp. 2840-2849
Author(s):  
Qingping Jin ◽  
Guangbo Wang ◽  
Tingying Liang ◽  
Peixia Chen
Keyword(s):  
Bond Slip ◽  
Gfrp Bars ◽  
Pull Out
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