Experimental and Numerical Analysis on the Bonding Performance of GFRP Bolts

2015 ◽  
Vol 777 ◽  
pp. 166-172
Author(s):  
Ya Chuan Kuang ◽  
Lian Wen Ou ◽  
Jin Xing Hu

By pull-out tests between GFRP bolts and concrete, the influence of the diameter and surface shape of GFRP bolts on the bonding performance was studied. By ANSYS analysis, the effects of anchorage length, diameter, geotechnical parameters and prestress on the bonding performance were studied. The experimental and numerical analysis results show that: with the increase of bolt diameter, the bonding strength of bolts decrease and the slippages increase. The bigger the parameters of rock-soil like modulus of elasticity, cohesion strength and internal friction angle are, the better is the bond behavior and the smaller is the slippage. The prestress plays an important role in the rock stability and the restriction of deformation. With the enhancement of the prestress of bolts, the peak shear stress increases but the effective anchorage length nearly stays the same.

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3649
Author(s):  
Fu Yi ◽  
Hui Li ◽  
Jia Zhang ◽  
Xutong Jiang ◽  
Maocheng Guan

Geotextile tubes are used in dam construction because fine tailings are difficult to use. The shear characteristics of geotextile tubes during dam operation are closely related to those of the materials used to construct the tubes. Pull-out tests can accurately reflect the interfacial shear characteristics between geosynthetics in practice, so pull-out tests were carried out for different interfacial types of polypropylene woven fabrics under dry and wet states. The effects of the type of interface and dry-wet states on the interfacial shear characteristics were investigated, and the impact mechanisms were also discussed. The results indicated that P-type interfaces (the warp yarn on the interface is parallel to the pulling direction) tended to harden. However, PTP-type (the warp yarn on the interface is perpendicular to each other) and T-type (the weft yarn on the interface is parallel to the pulling direction) interfaces softened first and then tended to plateau after reaching peak shear stress, and softening became more obvious at higher normal stresses. The displacement corresponding to peak shear stress (referred to as “peak displacement” in this paper) of interfaces was positively correlated with the normal stress, and the wet state reduced the interfacial peak displacement. For different types of interfaces, the peak displacement of the T-type interface was the largest, followed by PTP-type and P-type. Interfacial shear characteristics conformed to Mohr–Coulomb strength theory and, compared with quasi-cohesion values ranging from 1.334 to 3.606 kPa, the quasi-friction angle significantly contributed to the interfacial shear strength. The quasi-friction angle of the interface was composed of a sliding friction angle and an occlusal friction angle. The shear strength of the interface was more sensitive to the interface types than whether they were in the dry or wet state. For different types of interfaces and dry-wet states, the change in the interfacial shear strength is respectively affected by the occlusal friction angle and the sliding friction angle on the interface.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Xiaoyu Bai ◽  
Xueying Liu ◽  
Mingyi Zhang ◽  
Yonghong Wang ◽  
Zheng Kuang ◽  
...  

Glass fiber reinforced polymer (GFRP) antifloating anchors are widely used in reinforcing underground structures. Despite the outstanding application advances of GFRP anchors in the antifloating field, research on the mechanical transmission and deformation properties of the anchor rod and anchorage body is still scarce. This paper introduces pull-out experiments of GFRP antifloating anchors based on the FBG sensor strings technology. The experimental data demonstrates that the distribution curve of the axial stress shows a reversed-S shape, and the shear stress distribution presents the law of increasing first and then decreasing from the position of peak shear stress. The rod-anchorage body displacement difference curves of the anchors with an anchorage length that is closer to the critical anchorage length are smoother than those of the anchors with a larger length difference from the critical anchorage length. Finally, a simplified distribution model of the shear stress is applied for predicting the rod-anchorage body displacement difference, and the experimental data of the anchors with a rod slip failure is more applicable for this model than that of the anchors with a rod rupture failure.


Author(s):  
Mostafa Zeinoddini ◽  
Mahmood Nabipour

Since their inception suction caisson foundations have presented themselves as proven means of anchoring floating production systems and fixed offshore structures. The pull-out capacity of suction caissons remains a critical issue in their applications, and in order to produce effective designs, reliable methods of predicting the capacity are required. In this paper results from a numerical investigation on the behaviour of the suction caissons in clays against pull-out loading have been presented. Soil nonlinearities, soil/caisson interactions and the effects from the suction on the behaviour have been taken into account. A linear relationship has been observed between the soil cohesion values and the pull-out capacity. Under drained conditions, beyond specific limits of soil cohesion values, the increase in the cohesion value have found to demonstrate no further influence on the pull-out capacity. The soil internal friction angle has been noticed to have an exponential increasing effect on the pull-out capacity. With constant values of the caisson diameter, an increase in the aspect ratio noticed to have a second order effect of the friction originated part and a linear influence on the cohesion originated part of the resistance. With constant values of the caisson length, an increase in the aspect ratio values has found to result in an exponential decrease of the pull-out capacity. Based on the obtained numerical results simple formulations and approximations have been proposed in order to estimate the effects of the studied parameters on the pull-out capacities.


2020 ◽  
Vol 20 (4) ◽  
pp. 207-217
Author(s):  
Yongjin Choi ◽  
Jaehun Ahn

The <i>p-y</i> curve method and </i>p</i>-multiplier (<i>P<sub>m</sub></i>), which implies a group effect, are widely used to analyze the nonlinear behaviors of laterally loaded pile groups. Factors affecting <i>P<sub>m</sub></i> includes soil properties as well as group pile geometry and configuration. However, research on the change in <i>P<sub>m</sub></i> corresponding to soil properties has not been conducted well. In this study, in order to evaluate the effect of soil properties on the group effect in a laterally-loaded pile group installed in sandy soil, numerical analysis for a single pile and 3×3 pile group installed in loose, medium, and dense sand, was performed using the 3D numerical analysis program, Plaxis 3D. Among the factors considered in this study, the column location of the pile was the most dominant factor for <i>P<sub>m</sub></i>. The effect of the sand property change on <i>P<sub>m</sub></i> was not as significant as that of the column location of the pile. However, as the sand became denser and the friction angle increased, the group effect increased, leading to a decrease in <i>P<sub>m</sub></i> of approximately 0.1. This trend was similar to the result reported in a previous laboratory-scale experimental study.


Holzforschung ◽  
2010 ◽  
Vol 64 (6) ◽  
Author(s):  
Kiho Jung ◽  
Satoru Murakami ◽  
Akihisa Kitamori ◽  
Wen-Shao Chang ◽  
Kohei Komatsu

Abstract The purpose of this study was to develop eco-friendly and high-performance glued-in-rod (GIR) joints using compressed wood (CW), which has higher tensile strength than normal hardwood, instead of conventional wooden dowels. To explore the bonding performance of the dowel and base material, punching shear tests were performed and relationships were established between the density of CW dowel and punching characteristics. Pull-out tests of GIR joints were performed and results were compared with those derived from a mechanical model to evaluate the influence of insertion length of dowel and to define its optimized length. The results indicate that CW dowel has almost the same bonding performance in the density range 330–1000 kg m-3. Hence, CW as a dowel material in GIR joints has a high application potential. Pull-out tests of GIR joints showed that the insertion length of dowel in GIR joints with the CW-67 dowel is the best if the length is 10 times larger than its diameter. In addition to its satisfactory bonding performance, CW dowels have excellent tensile characteristics.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Enmao Quan ◽  
Yangsen Cao ◽  
Hongke Xu

To broaden the application of the basalt fiber in the preventive maintenance of asphalt pavement, this study investigated the bonding performance and evaluated the comprehensive performance of the basalt fiber asphalt macadam seal. Firstly, different types of basalt fiber asphalt macadam seal were prepared. The influences of content and length of the basalt fiber and dosage of emulsified asphalt on the bonding performance of the asphalt macadam seal were analyzed and compared. Next, by using the efficacy coefficient method, comprehensive performance considering both mechanical and economic characteristics of the basalt fiber asphalt macadam seal was evaluated. After that, reasonable content of each material was determined. Finally, the strengthening mechanism of the fiber on the bonding performance of macadam seals was revealed from a microscopic view. The results showed that compared with the ordinary asphalt macadam seal, the loss aggregate rate of the basalt fiber asphalt macadam seal was 11.0–30.5% lower, and the pull-out strength, shear strength, and torsional shear strength were 11.7–16.3%, 9.7–22.4%, and 4.2–20.6% higher, respectively. Considering the bonding performance and economic benefits, the optimal amount of emulsified asphalt and basalt fiber was 1.6 kg/m2 and 70 g/m2, respectively. Basalt fiber increased the cohesion of the asphalt material and improved the bonding performance of asphalt macadam seals through formation of the three-dimensional network structure. This study can provide reference to the application of basalt fibers in asphalt pavement maintenance.


2020 ◽  
Vol 10 (2) ◽  
pp. 153-164
Author(s):  
Hui Zheng ◽  
Dongdong Zhou ◽  
Xinfeng Yin ◽  
Lei Wang

Ultra-high-performance concrete (UHPC) material, a new type of cement-based composite material, is usually employed in the bridge engineering. The transfer and anchorage length of steel strand in UHPC material is different from that in ordinary concrete; nevertheless, few design standards are found that how to anchor the transfer and anchoring length of steel strand in UHPC material under normal curing. Through central pull-out test under the different conditions of protective layer thickness and embedded length, the load-slip curves, failure modes, and bond strength of 36 UHPC material specimens under normal curing were studied. The experimental results showed that the ultimate bond stress between UHPC material and steel strand under natural curing conditions is 7.01∼11.68 MPa. When the compressive strength of cube was 157 MPa; the bond strength under natural curing was smaller than that under thermal curing; when the thickness of the protective layer of steel strand with a diameter of 15.2 mm is greater than 30 mm, it had a little influence on bond strength. The regression analysis of the test results based on the experimental results proves that the recommended formulas for the design of transfer length and anchorage length of steel strand in UHPC material were in great agreement with the results of published studies.


2011 ◽  
Vol 255-260 ◽  
pp. 345-349 ◽  
Author(s):  
Bing Xiong Tu ◽  
Jin Qing Jia ◽  
Hong Sheng Yuan ◽  
Hai Tao Wang

This paper proposes a new model to calculate anchorage length for the compression anchor. Then the analytic solutions for the effective length and the critical length are derived according to the model. The analysis to the solutions show that the larger the rock mass’s elastic modulus, cohesion and internal friction angle, the smaller the anchorage length. Besides, the larger the load, the greater the anchorage length. However, the poisson’s ratio of rock mass nearly has no influence on the anchorage length. It is most important that the two calculation length show great agreement with present codes or specification.


2016 ◽  
Vol 60 (1) ◽  
pp. 13-20 ◽  
Author(s):  
P. Pokorný ◽  
J. Čech ◽  
P. Tej ◽  
M. Vokáč

Abstract To begin with, the intorduction of this paper summarises literature sources that wrongly interpret results of the bond strength between hot-dip galvanised reinforcements and concrete. The influence of the total reinforcement anchorage length on the bond strength results assessment was studied in detail. The numeric analysis of beam models with various testing anchorage lengths (the analysis input data comprised the results of previous bond strength tests carried out in a laboratory) unambiguously confirmed that when the bond strength between concrete and hot-dip galvanised reinforcement with a sufficient test anchorage length is tested in a beam test, the negative impact of the coating corrosion on bond strength with concrete may be biased. It is more objective to test bond strength with concrete in a pull-out test where a very short test reinforcement anchorage length is set out as a standard.


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