• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.827-832
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• 2003

This study presented the reinforcing effect of sands by using newly devised 3D Tirecell. Plate loading tests for sand were conducted for different relative density and number of reinforced layers. From the tests, the ultimate bearing capacity of reinforced sand increased with increasing relative densities. The effect of reinforced layers with 0.4B interval is limited to 2 layers and further reinforcing effects can not be obtained beyond 3 layers. Especially the bearing capacity increased remarkably at 1 layer of Tirecell reinforcement and the degree of increase was small for 1 layer to 2 layers increase of reinforcement. Test results show that the reinforcing effect of Tirecell is prominent compared with commercial geocell in the literature.

• Geomechanics and Engineering
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• v.9 no.3
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• pp.373-395
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• 2015

Comprehensive results from cyclic plate loading at a diameter of 300 mm supported by layers of geocell are presented. The plate load tests were performed in a test pit measuring $2000{\times}2000mm$ in plane and 700 mm in depth. To simulate half and full traffic loadings, fifteen loading and unloading cycles were applied to the loading plate with amplitudes of 400 and 800 kPa. The optimum embedded depth of the first layer of geocell beneath the loading plate and the optimum vertical spacing of geocell layers, based on plate settlement, are both approximately 0.2 times loading plate diameter. The results show that installation of the geocell layers in the foundation bed, increase the resilient behavior in addition to reduction of accumulated plastic and total settlement of pavement system. Efficiency of geocell reinforcement was decreased by increasing the number of the geocell layers for all applied stress levels and number of cycles of applied loading. The results of the testing reveal the ability of the multiple layers of geocell reinforcement to 'shakedown' to a fully resilient behavior after a period of plastic settlement except when there is little or no reinforcement and the applied cyclic pressure are large. When shakedown response is observed, then both the accumulated plastic settlement prior to a steady-state response being obtained and the resilient settlements thereafter are reduced. The use of four layers of geocell respectively decreases the total and residual plastic settlements about 53% and 63% and increases the resilient settlement 145% compared with the unreinforced case. The inclusion of the geocell layers also reduces the vertical stress transferred down through the pavement by distributing the load over a wider area. For example, at the end of the load cycle of the applied pressure of 800 kPa, the transferred pressure at the depth of 510 mm is reduced about 21.4%, 43.9%, 56.1% for the reinforced bases with one, two, and three layers of geocell, respectively, compared to the stress in the unreinforced bed.

• Journal of the Korea Furniture Society
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• v.20 no.4
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• pp.281-289
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• 2009

This research examined the technical feasibility of composite that had two layers of fiberglass reinforcement to enhance the load carrying capacity of lumber. Specimens were prepared from standard lumber made of thinning crop trees such as Larix kaempferi, Pinus koraiensis, and P. rigida. Results indicated that bending properties, hardness, and wood screw withdrawal load of low density lumber from the P. koraiensis increased as the number of layers of fiberglass reinforcement increased. Composite produced by VARTM method showed the MOE increased in all specimens, while the MOR differed on the location, whether the 2-layers of FRP is put on tensile zone or compressive zone. The MOR of high density lumber from Larix kaempferi and P. rigida decreased when they placed into tensile zone, but low density lumber from P. koraiensis increased in same location. The bending toughness only increased high density lumber of Larix kaempferi as the number of layers of fiberglass reinforcement increased. The technique developed by this study may increase an opportunity to use small diameter log with low density for commercial purposes.

• Journal of the Korea Furniture Society
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• v.21 no.5
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• pp.347-353
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• 2010

This research examined the technical feasibility of composite that had 2- and 3- layers of fiberglass reinforcement to enhance the load carrying capacity of particleboard. Specimens were prepared from commercial particleboard. Results indicated that bending properties, hardness and impact bending energy increased as the number of layers of fiberglass reinforcement increased. The wood screw withdrawal load only decreased at the 3-layer of fiberglass reinforcement. The technique developed by this study may increase an opportunity to use particleboard for structural purposes.

• Journal of the Korea Institute of Building Construction
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• v.3 no.2
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• pp.119-127
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• 2003

Test specimen test was performed using concrete reinforced with fiber sheet and the test variables were based on the kinds of fiber and the number of reinforcement layers. Using steel-concrete reinforced with fiber sheet, compression tests were performed and the test variables were the kinds of fiber, number reinforcement layers and reinforcement layer order. The following results were obtained: 1) It was demonstrated that compressive strength of the test specimen reinforced during test specimen test and member test increased as the number of reinforcement layers increased. 2) It was shown that non-reinforced test, specimen were destroyed during the member tests, but the specimen reinforced with CFS destroyed and the GFS-reinforced specimen and composite reinforced specimen showed ductile destruction. 3) As a result of tests on kinds of reinforcement fiber, it was demonstrated that CFS-reinforced test specimen had higher compressive strength in a 공시체 test. In the member test, 2ply-and 3ply-GFS reinforced specimens except lplied one had higher compressive strength. It was because partial destruction occurred due to the rate of height/section. 4) For layer strength order, compared with test specimen reinforced only with a single reinforced material, test specimen reinforced with CFS and GFS, and test specimen reinforced with CFS first showed better results in compressive strength and ductility judgement.

• Geomechanics and Engineering
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• v.8 no.4
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• pp.595-613
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• 2015

An experimental investigation into the uplift capacity of horizontal square plate anchors in sand with and without geogrid reinforcement is reported. The parameters investigated are the effect of the depth of the single layer of geogrid, vertical spacing of geogrid layers, number of geogrid layers, length of geogrid layers, the effects of embedment depth, and relative density of sand. A series of three dimensional finite element analyses model was established and confirmed to be effective in capturing the behaviour of plate anchor-reinforced sand by comparing its predictions with experimental results. The results showed that the geogrid reinforcement had a considerable effect on the uplift capacity of horizontal square plate anchors in sand. The improvement in uplift capacity was found to be strongly dependent on the embedment depth and relative density of sand. A satisfactory agreement between the experimental and numerical results on general trend of behaviour and optimum geometry of reinforcement placement is observed. Based on the model test results and the finite element analyses, optimum values of the geogrid parameters for maximum reinforcing effect are discussed and suggested.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.39-45
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• 2010

The effects of non-woven geotextiles on mechanical behavior of sand were investigated. A comprehensive series of triaxial compression tests were performed for these investigation on unreinforced and reinforced sand with geotextiles. The Joomunjin standard sand was used and non-woven geotextiles were included into sand specimen with three layers. The inclusion of non-woven geotextile reinforcement into sand increased the peak strength of sand significantly and the reinforced samples exhibited a greater axial strain at failure. Also the effect on number of reinforcement layers was studied and found as increasing the number of reinforcement layers resulting in more ductility by clogging developed in the shear band within the specimens. It was also found that the tendency of samples to dilate is restricted by non-woven geotextile inclusion. The effect of nunber of reinforcement layer increasing is just same to the effect of decreasing void ratio of sand in this case.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.107-117
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• 2004

A series of model tests were conducted to investigate how the number of reinforcement layers, stiffnesses, types of reinforcement material and buried depth of a flexible pipe can affect bearing capacity-settlement curve at a loose sand foundation. In the test results, whereas the type of failure in unreinforced sand was local shear, the type of failure, for model tests with more than 2 reinforcement layers in loose sand, was general shear: The number of the optimum reinforcement layers was found to be two: Stiffness and type of reinforcement were more important than the maximum tensile strength of reinforcement in improving bearing capacity. When the depth of buried pipe from the sand surface was less than the width of the footing, test results showed that both bearing capacity and ultimate bearing capacity of buried pipe in unreinforced sand significantly decreased, and the type of failure in the reinforced sand changed from general shear to local shear.

• Geomechanics and Engineering
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• v.12 no.2
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• pp.327-346
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• 2017

Laminated plates have many applications in different industrials. Buckling analysis of these structures with the nano-scale reinforcement has not investigated yet. However, buckling analysis of embedded laminated plates with nanocomposite layers is studied in this paper. Considering the single-walled carbon nanotubes (SWCNTs) as reinforcement of layers, SWCNTs agglomeration effects and nonlinear analysis using numerical method are the main contributions of this paper. Mori-Tanaka model is applied for obtaining the equivalent material properties of structure and considering agglomeration effects. The elastic medium is simulated by spring and shear constants. Based on first order shear deformation theory (FSDT), the governing equations are derived based on energy method and Hamilton's principle. Differential quadrature method (DQM) is used for calculating the buckling load of system. The effects of different parameters such as the volume percent of SWCNTs, SWCNTs agglomeration, number of layers, orientation angle of layers, elastic medium, boundary conditions and axial mode number of plate on the buckling of the structure are shown. Results indicate that increasing volume percent of SWCNTs increases the buckling load of the plate. Furthermore, considering agglomeration effects decreases the buckling load of system. In addition, it is found that the present results have good agreement with other works.

• Geomechanics and Engineering
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• v.34 no.6
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• pp.623-636
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• 2023

This study utilized small-scale physical model tests to investigate the impact of different types of geosynthetics, including geocell, planar geotextile, and wraparound geotextile, on the behaviour of strip footings placed on 0.8 m thick soil fills and backfills with a slope angle of 70°. Bearing capacity and settlement of the footing and failure mechanisms are discussed and evaluated. The results revealed that the bearing capacity of footings situated on both unreinforced and reinforced slopes increased with a greater embedment depth of the footing. For settlement ratios below 4%, the geocell reinforcement exhibited significantly higher stiffness, carrying greater loads and experiencing less settlement compared to the planar and wraparound geotextile reinforcements. However, the performance of geocell reinforcement was influenced by the number and length of the geocell layers. Increasing the geocell back length ratio from 0.44 to 0.84 significantly improved the bearing capacity of the footing located at the crest of the reinforced slope. Adequate reinforcement length, particularly for geocell, enhanced the bearing pressure of the footing and increased the stiffness of the slope, resulting in reduced deflections. Increasing the length of reinforcement also led to improved performance of the footing located on wraparound geotextile reinforced slopes. In all reinforcement cases, reducing the vertical spacing between reinforcement layers from 100 mm to 75 mm allowed the slope to withstand much greater loads.