Load-strain-displacement response of geosynthetics in monotonic and cyclic pullout

1998 ◽  
Vol 35 (2) ◽  
pp. 183-193 ◽  
Author(s):  
D M Raju ◽  
R J Fannin
Keyword(s):  
Relative Displacement ◽  
Cyclic Loads ◽  
Normal Stresses ◽  
Constant Ratio ◽  
Pullout Resistance ◽  
Maximum Resistance ◽  
Constant Rate ◽  
Pullout Testing ◽  
Pullout Behaviour ◽  
Cyclic Dynamic

Mobilization of the pullout resistance of geosynthetics in monotonic and cyclic modes is described from both displacement- and load-controlled tests performed at normal stresses in the range 4-17 kPa. The tests were performed on three geogrids and two geomembranes embedded nearly 1.0 m in a uniformly graded sand. Results for load-controlled tests at a constant rate of 0.25 kN/(m ·min-1), followed by several series of load cycles of increasing amplitude, are compared with displacement-controlled tests at a constant rate of 0.5 mm/min. In general the geogrids behave as an equivalent textured sheet. Pullout behaviour, and especially the incremental displacement mobilized at cyclic loads close to the maximum resistance, is found to vary with type of geogrid. In only one case was cyclic pullout resistance of a grid found to exceed the monotonic resistance. A comparison of the cyclic and monotonic response yields a constant ratio of pullout resistance at large displacement, but one which is not unique to a particular specimen. Cyclic strains of decreasing amplitude are mobilized along a test specimen, with most of the necessary relative displacement occurring close to the loaded end and the embedded end showing little response.Key words: pullout testing, monotonic, cyclic, dynamic, geosynthetics, reinforced walls.

Analytical model of interaction between hexagonal wire mesh and silty sand backfill

2001 ◽  
Vol 38 (4) ◽  
pp. 782-795 ◽  
Author(s):  
D T Bergado ◽  
P Voottipruex ◽  
A Srikongsri ◽  
C Teerawattanasuk
Keyword(s):  
Analytical Model ◽  
Relative Displacement ◽  
Wire Mesh ◽  
Silty Sand ◽  
Hyperbolic Function ◽  
Friction Resistance ◽  
Pullout Resistance ◽  
Mesh Reinforcement ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

The interaction behavior between hexagonal wire mesh and silty sand backfill can be evaluated from pullout tests. The pullout resistance of the hexagonal wire mesh reinforcement consists of two components, namely friction resistance and passive bearing resistance. The friction resistance – relative displacement relationship of a hexagonal wire mesh can be simulated by a linear elastic – perfectly plastic model. The passive bearing resistance of an individual bearing member can be modelled by a hyperbolic function. The friction resistances for galvanized and PVC-coated hexagonal wire mesh were 25 and 21%, respectively, of the total pullout resistance. A new analytical model for predicting the pullout resistance of hexagonal wire mesh reinforcement has been proposed. The proposed solution can estimate the maximum pullout force at different reinforcement levels from observed horizontal movement of a hexagonal wire mesh reinforcement.Key words: hexagonal wire mesh, necking phenomena, bearing resistance, analytical model, pullout box, bearing resistance.

Experimental Investigation of Steel Confinement of Clustered Large-Size Stud Shear Connector in Full-Depth Precast Bridge Deck Panel

2020 ◽  
Vol 856 ◽  
pp. 99-105
Author(s):  
Krissachai Sriboonma ◽  
Sacharuck Pornpeerakeat
Keyword(s):  
Bridge Deck ◽  
Precast Concrete ◽  
Relative Displacement ◽  
Wire Mesh ◽  
Shear Connector ◽  
Maximum Resistance ◽  
Large Size ◽  
Different Types ◽  
Concrete Bridge Deck ◽  
Stud Shear Connector

The research focuses on investigating different types of steel confinements around a clustered large-size stud shear connector using in full-depth precast concrete bridge deck panel. The tests were based on Push-off test of two main groups of specimens: (1) the specimens with 4-stud shear connector where three different types of confinement were adopted including of O-ring confinement, Wire-mesh confinement, and L-angle confinement), and (2) the specimens with 8-stud shear connector where two different types of confinement were investigated including of Plate-ring confinement and L-angle confinement. The test results concluded that L-angle confinement type of the group of specimens with 4-Stud is the most sufficient type comparing between the different types of confinement in the same group. The maximum resistance was found at 41-ton, while as the displacement was found to be the most expansible and gradually reduced until the failure point. This means that the sign of failure can be noticeable prior to a collapse of the structure. For the group of specimens with 8-Stud, the resistance of this group was higher than the group of specimens with 4-Stud about 50 - 100% increase depending on each type of confinement. The maximum resistance was found for Plate-ring confinement type at 70-ton, which was agreed with the increment of the displacement about 20 - 50%. In comparison between specimens with 8-Stud, the Plate-ring confinement showed greater resistance and more relative displacement about 15% than the L-angle confinement.

Analysis of the Pullout Testing of Straight and Angled Abutments in Narrow Diameter Implants

2020 ◽  
Vol 1012 ◽  
pp. 461-465
Author(s):  
Ana Lígia Piza Micelli ◽  
Frederico Nigro ◽  
Cristiano Stefano Mucsi ◽  
Maicon Cavalieri ◽  
Luís Cláudio Aranha ◽  
...  
Keyword(s):  
Statistical Difference ◽  
Mechanical Stability ◽  
Screw Loosening ◽  
Pullout Resistance ◽  
Osseointegrated Implants ◽  
Fixation Screw ◽  
Pullout Testing ◽  
Pullout Load ◽  
Common Problems ◽  
Narrow Diameter Implants

Despite the success of osseointegrated implants, some biomechanical problems such as loosening or fracture of the abutment, crown fixation screw loosening and prosthetic instability, are common problems reported in the literature. Thus, the objective of the present study was to analyze the pullout resistance of straight and angled abutments in narrow diameter implants installed by means of friction. The specimen was composed of an implant of 3.3 mm x 11 mm fixed 2 mm above of a resin block. The abutments were fixed by friction receiving 3, 5 and 7 strikes of 0.05 J along the implant axis, and were positioned with 0 ̊, 10 ̊ and 20 ̊ of angulation. The abutments were subjected to pullout load, totalizing 10 repetitions for each test, i.e., the abutment was reinserted up to 10 times in the same implant. The results showed higher values of pullout load for the abutments with 7 strikes, and no statistical difference with 5 strikes suggesting better mechanical stability.

Comparison of Pullout Behaviour on Sand between Planer Grid Forms and Grid with Rib of Reinforcement

2010 ◽  
Vol 143-144 ◽  
pp. 1012-1016
Author(s):  
Yong Liang Lin ◽  
Meng Xi Zhang ◽  
Chun Cai
Keyword(s):  
Reinforced Soil ◽  
Grid Size ◽  
Soil Reinforcement ◽  
Testing Program ◽  
Pullout Force ◽  
Pullout Resistance ◽  
Pullout Tests ◽  
Soil Structures ◽  
Pullout Behaviour ◽  
Grid Reinforcement

In conventional reinforced soil structures, the reinforcements are often laid horizontally in the soil. In this paper, a new concept of grid reinforcement with ribbed inclusions is proposed. In the proposed of soil reinforcement, besides conventional grid reinforcements, some vertical and 3D reinforcing rib are also placed in the soil. Pullout tests are necessary in order to study the interaction behavior between soil and geosynthetics in the anchorage zone. Then, a series of pullout tests are conducted and the various parameters studied in this testing program include rib height and grid size of reinforcement. The result shows that the ultimate pullout force of plexiglass with rib is significantly larger than ordinary ones in the same normal stress. Ultimate pullout resistance increased as the increase of the height of tooth, and also is significantly impacted by grid size.

Response of buried steel pipelines subjected to relative axial soil movement

2009 ◽  
Vol 46 (7) ◽  
pp. 735-752 ◽  
Author(s):  
Dharma Wijewickreme ◽  
Hamid Karimian ◽  
Douglas Honegger
Keyword(s):  
Earth Pressure ◽  
Axial Direction ◽  
Full Scale ◽  
Interface Shear ◽  
Dense Sand ◽  
Pullout Resistance ◽  
Soil Movement ◽  
Pullout Testing ◽  
Research Findings ◽  
Dry Sand

The performance of buried steel pipelines subjected to relative soil movements in the axial direction was investigated using full-scale pullout testing in a soil chamber. Measured axial soil loads from pullout testing of pipes buried in loose dry sand were comparable to those predicted using guidelines commonly used in practice. The peak values of axial pullout resistance observed on pipes buried in dense dry sand were several-fold (in excess of 2 times) higher than the predictions from guidelines; the observed high axial pullout resistance is primarily due to a significant increase in normal soil stresses on the pipelines, resulting from constrained dilation of dense sand during interface shear deformations. This reasoning was confirmed by direct measurement of soil stresses on pipes during full-scale testing and numerical modeling. The research findings herein suggest that the use of the coefficient of lateral earth pressure at-rest (K0) to compute axial soil loads, employing equations recommended in common guidelines, should be undertaken with caution for pipes buried in soils that are likely to experience significant shear-induced dilation.

On the pullout resistance of geosynthetics

1993 ◽  
Vol 30 (3) ◽  
pp. 409-417 ◽  
Author(s):  
R.J. Fannin ◽  
D.M. Raju
Keyword(s):  
Relative Displacement ◽  
Coarse Sand ◽  
Reinforced Soil ◽  
Small Displacement ◽  
Sand Sample ◽  
Similar Response ◽  
Pullout Resistance ◽  
Interaction Factor ◽  
Values In Design ◽  
Stress Dependent

Pullout tests are reported on geosynthetic test specimens embedded in a relatively dense, coarse sand sample. The tests are displacement controlled and are performed at different vertical effective stresses. Tests are reported for a smooth and textured geomembrane and for geogrids of a high and low junction strength. Behaviour is compared with an inextensible, rough sheet. Pullout resistance is governed by progressive tensile strain in the geosynthetic which is a result of relative displacement between it and the soil. Values of interface bond that are described by an interaction factor vary significantly and are stress dependent. Both types of geogrid and the textured geomembrane exhibit a similar response to loading at small displacement, and mobilize a much larger interaction factor than the smooth geomembrane. A rationale is suggested for selection of appropriate values in design. Key words : pullout testing, geogrid, geomembrane, interface friction, reinforced soil.

scholarly journals Slip-shakedown analysis and the assumption of small coupling in frictional contact

2008 ◽  
Vol 30 (4) ◽  
Author(s):  
Nicolas Antoni ◽  
Nguyen Quoc Son
Keyword(s):  
Coulomb Friction ◽  
Frictional Contact ◽  
Limit Load ◽  
Relative Displacement ◽  
Elastic Response ◽  
Cyclic Loads ◽  
Shakedown Analysis ◽  
Small Coupling ◽  
Coulomb Criterion ◽  
Contact Pressures

In the frictional contact of solids under cyclic loads, the shakedown behaviour of the relative displacement is of interest in the same spirit as the plastic deformation in plasticity. Cumulative slips may lead to the failure due to large relative displacements of the components of an assembly while cyclic slips are often undesired because of wear and fretting÷fatigue problems. Under Coulomb friction, it is well known that Melan and Koiter theorems are generally not available, except in certain particular cases. In this discussion, the particular case of small coupling between the contact pressures and the slip-displacements is considered. This assumption means that the tangent displacements have small or no influence on the contact pressures which can be then computed from the elastic response as in the uncoupling case. The pressure is thus a given time-dependent function and the Coulomb criterion is reduced to a Mises-like standard law of friction. It is shown here that Melan and Koiter theorems can be applied again as in standard plasticity. The dependence of the yield limit on the loading amplitude is however not classical and the extension of the static and kinematic approaches is discussed to obtain the critical shakedown load or the limit load. The validity of the assumption of small coupling is also explored by numerical simulation in a practical example.

Numerical simulation of pullout response for planar soil reinforcements

1999 ◽  
Vol 36 (3) ◽  
pp. 455-466 ◽  
Author(s):  
N Gurung ◽  
Y Iwao
Keyword(s):  
Numerical Simulation ◽  
Parametric Study ◽  
Interface Design ◽  
Interaction Mechanism ◽  
Relative Displacement ◽  
Reinforced Soil ◽  
Test Results ◽  
Relative Stiffness ◽  
Pullout Tests ◽  
Pullout Testing

This paper presents a series of numerical simulations for laboratory and field pullout tests. A nonlinear differential expression for interface pullout from simple equilibrium of forces and hyperbolic interface model for shear displacement variation along the length of the planar reinforcement is utilised. Finite difference numerical method and nondimensional expressions are adopted for wider application. The relative stiffness and relative displacement parameters are defined and related to the interface pullout interaction mechanism. A parametric study to develop computer-simulated interface design charts for a practical range of relative stiffness and relative bond resistance is theoretically illustrated. The pullout model is capable of simulating the responses of inextensible as well as highly extensible planar reinforcements. The model responses compared satisfactorily with the available theoretical and experimental pullout test results for steel straps, polymer strips, geotextiles, geomembranes, nylon geosynthetics, and geogrid reinforcements.Key words: geosynthetics, extensible reinforcement, numerical simulation, parametric study, pullout testing, reinforced soil.

scholarly journals Pullout behaviour of inclined shallow plate anchors in sand

2021 ◽  
Author(s):  
Peizhi Zhuang ◽  
Hongya Yue ◽  
Xiuguang Song ◽  
Xu Guo ◽  
Hongbo Zhang ◽  
...  
Keyword(s):  
Empirical Method ◽  
Image Correlation ◽  
Deformation Mechanisms ◽  
Interface Conditions ◽  
Pullout Capacity ◽  
Inclined Plate ◽  
Pullout Resistance ◽  
Inclination Angles ◽  
Pullout Behaviour ◽  
Plate Anchors

This paper presents an experimental study on the pullout behaviour of inclined shallow plate anchors subject to axial pull in sand. The 1g model tests were performed to examine the effects of anchor inclination and sand-anchor interface conditions on the load-displacement response and the associated failure and deformation mechanisms of plate anchors at various embedment ratios and sand densities. The anchor pullout capacity was found to increase continuously with the load inclination angle to the vertical (), and the increase was more significant for  from º to º. The effect of sand-anchor interface conditions was negligible for horizontal plate anchors (º) but it became increasingly significant at larger inclination angles. The effects of these two factors both decreased with an increasing embedment ratio. Their influences on the failure and deformation mechanisms were measured and analysed using a digital image correlation (DIC) technique. Based on the test data and results available in the literature, a simple empirical method for the prediction of pullout resistance of inclined plate anchors in sand is calibrated and recommended.

Constant-Rate Feed Device. A Reply to Comment

1950 ◽  
Vol 22 (7) ◽  
pp. 956-956 ◽  
Author(s):  
Lester Lundsted
Keyword(s):  
Constant Rate ◽  
Feed Device
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