The Influence of Geometric Structure of Geogrids on the Pullout Resistance

2011 ◽  
Vol 261-263 ◽  
pp. 586-590
Author(s):  
Di Wu ◽  
Chao Xu
Keyword(s):  
Geometric Structure ◽  
Geometric Characteristic ◽  
Test Results ◽  
Pullout Force ◽  
Unresolved Problem ◽  
Pullout Resistance ◽  
Reinforced Soils ◽  
Pull Out ◽  
Pullout Tests

The influence of geometric characteristic of geogrid on pullout behavior is still an unresolved problem in the application of geosynthetic reinforced soils. The laboratory pullout tests were employed to investigate the effects of geometric structure features on the pull-out test results. The results of this study indicate that the effect of geometric structure on pullout behavior is reflected in two aspects: geogrid type and mesh form of geogrid. The variation of geogrid types can lead to the changes of the pullout force and pullout modulus. For the latter one, the reduction of longitudinal and transverse geogrid ribs not only causes the decrease of friction and transverse rib bearing resistance, but also changes the mesh form which is the geometric structure of grids.

Effect of Wetting on the Pullout Resistance of Grouted Soil Nails

2012 ◽  
Vol 226-228 ◽  
pp. 1304-1307
Author(s):  
Jason Y. Wu ◽  
Jr Min Chang
Keyword(s):  
Fine Sand ◽  
Shear Resistance ◽  
Test Results ◽  
Pullout Capacity ◽  
Interface Shear ◽  
Soil Nails ◽  
Soaking Time ◽  
Pullout Resistance ◽  
Soil Nail ◽  
Pullout Tests

In this research, laboratory pullout tests were conducted on grouted soil nails to study the effect of wetting on the interface shear resistance between nail and soil during pullout. Deformed bars with equal size to the true soil nails were used as model nails. The soil used was silty fine sand collected at the site and prepared to a very dense condition. Rainfall infiltration was simulated using duplicated soil nails inundated by water for different periods. Test results indicated that the peak pullout resistance strongly decreases upon wetting, with a reduction of about 60% after soaking for 28 days. However, the experiments showed that there is a threshold water content (or soaking time) beyond which the effect of infiltration on the pullout resistance is reduced. The laboratory protocols developed in this study offered an easy scheme for the prediction of the pullout capacity of a grouted soil nail upon wetting.

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.

scholarly journals Determination of Pullout Strength of Geogrid in Sandy Soil

2020 ◽  
Vol 9 (3) ◽  
pp. 1835-1840
Keyword(s):  
Mechanical Property ◽  
Laboratory Tests ◽  
Pullout Test ◽  
Significant Finding ◽  
Pullout Strength ◽  
Pullout Resistance ◽  
Pull Out ◽  
Pullout Tests ◽  
Selection Of

Geogrid reinforcement of soil has been successfully used for many years in a wide variety of applications. This paper presents data obtained from a series of laboratory tests performed on the geogrid. The tests were conducted to determine the mechanical property including the tensile strength of the geogrid and its corresponding pullout test. Tests were performed to find out the effect of width of geogrid on the pullout resistance. It was found that the pull-out resistance of geogrid is a function of the relative density of the soil, the length and the width of geogrid specimen. A mechanism of soil-geogrid interaction is described and used to explain the results of' the pull-out tests. A significant finding is that the selection of geogrid specimen dimensions for laboratory pullout tests must take into account the strain to failure of the soil and the stiffness of the geogrid in order to properly represent the maximum pull-out stress that will be available in field applications.

scholarly journals The Resistance of Denti-Geogrid Reinforcement in a Sand Model Based on the Pullout Test

2021 ◽  
Vol 8 ◽  
Author(s):  
Fang Wei ◽  
Zhang Jingsheng ◽  
Shi Lijun ◽  
Zha Xudong
Keyword(s):  
Earth Pressure ◽  
Decisive Role ◽  
Test Results ◽  
Pullout Resistance ◽  
Theoretical Approaches ◽  
Pullout Tests ◽  
Lateral Resistance ◽  
Lower Load ◽  
Lab Test ◽  
Analytical Approaches

In order to investigate the pullout resistance of the Horizontal-Vertical reinforcement, a “denti-geogrid” was assembled by bonding a “denti-strip” with the geogrid and the pullout tests were carried out. Subsequently, the analytical approaches were investigated to calculate the pullout resistance on the basis of the surface sliding model, Perterson and Anderson’s model, Jewell’s model, Chai’s model, and the proposed stress summation model. Moreover, a new index named “scale factor” was suggested to reflect the proportion of bearing resistance provided by transversal members. The research showed that: 1) under the same test conditions, the pullout resistance of denti-geogrid was much higher than that of a common geogrid. All common geogrids showed linear strain softening in the later stage of pullout tests. Given the same normal stresses, due to the expansion of effective areas suffering lateral earth pressure, more denti-strips meant more significant resistance; 2) Among five theoretical approaches, the solutions of the proposed stress summation model made the best agreement with lab test results, with an average relative error of 2.82%. On the other hand, the stress summation model also showed a simplicity in calculation; and 3) Due to higher gradient of the fitting curve of scale factors under lower load, the bearing resistance would be more and more dominant, which means that the lateral resistance of denti-strips could play a decisive role in cases of low stress level.

Influence of Silane Coupling Agent on Interfacial Strength of SMA Composite

2010 ◽  
Vol 143-144 ◽  
pp. 933-937
Author(s):  
Yu Long Wang ◽  
Zhen Qing Wang ◽  
Li Min Zhou ◽  
Hai Tao Huang
Keyword(s):  
Coupling Agent ◽  
Shape Control ◽  
Silane Coupling Agent ◽  
Interfacial Strength ◽  
Test Results ◽  
Surrounding Matrix ◽  
Pull Out ◽  
Damage Repair ◽  
Silane Coupling ◽  
Epoxy Matrix Composite

Shape memory alloy (SMA) can be embedded into a host material to achieve shape control, damage repair and self-adaption. It is well recognized that the applications of SMA composites are highly dependent on the integrity of SMA fiber-matrix interface. However, the interfacial debonding often occurs due to the weak bonding of interface between the SMA wire and its surrounding matrix. Therefore, it is necessary to improve interfacial strength of SMA composites. In present paper, the epoxy resin is functionalized by mixing different amount of silane coupling agent to improve the interfacial adhesion of SMA fiber reinforced epoxy matrix composite. The single fiber pull-out test is carried out to evaluate the interfacial strength and the test results indicate that the interfacial strength of SMA composite is improved significantly as compared to the results from unfunctionalized samples.

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.

scholarly journals Effect of Seismic Loading on Variation of Pore Water Pressure During Pile Pull-Out Tests in Sandy Soils

2021 ◽  
Vol 27 (12) ◽  
pp. 1-12
Author(s):  
Haider N. Abdul Hussein ◽  
Qassun S. Mohammed Shafiqu ◽  
Zeyad S. M. Khaled
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Seismic Loading ◽  
Shaking Table ◽  
Dense Sand ◽  
Pressure Transducers ◽  
Pull Out ◽  
Pullout Tests ◽  
Pile Model

Experimental model was done for pile model of L / D = 25 installed into a laminar shear box contains different saturation soil densities (loose and dense sand) to evaluate the variation of pore water pressure before and after apply seismic loading. Two pore water pressure transducers placed at position near the middle and bottom of pile model to evaluate the pore water pressure during pullout tests. Seismic loading applied by uniaxial shaking table device, while the pullout tests were conducted through pullout device. The results of changing pore water pressure showed that the variation of pore water pressure near the bottom of pile is more than variation near the middle of pile in all tests. The variation of pore water pressure after apply seismic loading is more than the variation before apply seismic loading near the middle of pile and near the bottom of pile and in loose and dense sand. Variation of pore water pressure after apply seismic loading and uplift force is less than the variation after apply seismic loading in loose sand at middle and bottom of pile.

PULL OUT STRENGTH FOR DIFFERENT SIZE OF DOWEL AND GRAIN DIRECTION OF GLULAM

2016 ◽  
Vol 78 (5-4) ◽  
Author(s):  
Tengku Anita Raja Hussin ◽  
Mohamad Iswandi Jinne ◽  
Rohana Hassan
Keyword(s):  
Failure Modes ◽  
Maximum Load ◽  
Experimental Program ◽  
Drilling Process ◽  
Test Results ◽  
Bond Behaviour ◽  
Pull Out ◽  
Timber Joints ◽  
Different Thickness ◽  
Pull Out Strength

This paper presents an experimental program for testing glued-in dowel glulam timber joints. Hundred thirty glulam specimens, each with a single glued-in rebar parallel to the grain and perpendicular to grain with different size of dowels 12mm, 16mm and 20mm were tested to evaluate the effects of anchorage length and different dowel diameter for parallel and perpendicular to the grain on pull-out strength and bond behaviour of glued-in rebar timber joints. The test results showed that the maximum load for specimen with dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction. Failure modes were characterized by pull out failure in the mode of adhesive-dowel, yet one sample failed in timber-adhesive mode. This might happened because the surface of the timber was burned by drilling machine during the drilling process. The pull-out was tested with different thickness grain direction with different dowel size with a rate of 2mm/min and the failure modes were observed after the testing of pull-out test. PRF is the adhesive used for the strengthening purposes. Resistance to the withdrawal of dowels glued-in perpendicularly was 44.2% to 53.5 % lower than that obtained for dowels glued-in parallel to the grain direction. The result shows that the dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction.

scholarly journals Effects of a Short Heat Treatment Period on the Pullout Resistance of Shape Memory Alloy Fibers in Mortar

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2278 ◽  
Author(s):  
Min Kyoung Kim ◽  
Dong Joo Kim ◽  
Young-Soo Chung ◽  
Eunsoo Choi
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Memory Effects ◽  
Stress Recovery ◽  
Pullout Resistance ◽  
Pullout Tests ◽  
Dog Bone ◽  
Shape Memory Effects ◽  
Short Time

The feasibility of the crack closure of cementitious composites reinforced with shape memory alloy (SMA) fibers was investigated by performing single-fiber pullout tests. To demonstrate the fast crack closing ability, in this study, a heat treatment (300 °C) was applied for a short time (10 min). A short heat treatment was applied for 10 min, after the slip reached 0.5 mm, to activate the shape memory effects of cold-drawn SMA fibers. Two types of alloys were investigated, NiTi and NiTiNb, with two geometries, either smooth or dog-bone-shaped. During the heat treatment, the pullout stress of the SMA fibers initially decreased due to thermal extension, and then increased after heating for 1–3 min, resulting from the shape memory effects. However, their pullout stress recovery during and after the heat treatment was different for the different alloys and fiber geometries. The NiTi fibers generally produced a higher and faster recovery in terms of their pullout stress than the NiTiNb fibers, while the dog-bone-shaped fibers showed a faster pullout stress recovery than the smooth fibers.

Bond and splitting in reinforced concrete: test results on bar pull-out

1996 ◽  
Vol 29 (5) ◽  
pp. 267-276 ◽  
Author(s):  
Pietro G. Gambarova ◽  
GianPaolo Rosati
Keyword(s):  
Reinforced Concrete ◽  
Test Results ◽  
Pull Out
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