• International Journal of Highway Engineering
• /
• v.3 no.1 s.7
• /
• pp.151-163
• /
• 2001

Very few studies have been attempted to understand the stress-strain behavior of flexible pavements reinforced with geosynthetics in the middle of asphalt layer. In this study, the flexible asphalt layer was analyzed with finite element method to understand stress-strain behavior. The asphalt layer was reinforced with glass grid and geogrid. The reinforcement was applied in the asphalt layer to prevent its excessive deformation and shear failure. The location of installation and stiffness of the geosynthetics were varied to obtain optimum depth of reinforcement and proper modulus. The results indicate that geosynthetics are more effective for reducing maximum shear stress than those of vertical stress and vertical displacement. Maximum shear stress decreased 15$\sim$20%, and glass grid with high value of modulus was the most effective. Also, in order to prevent failure of asphalt layer, reinforcement should be installed in the 3cm$\sim$5cm depth.

• Journal of Navigation and Port Research
• /
• v.26 no.3
• /
• pp.323-328
• /
• 2002

Soil-steel structures have been used for the underpass, or drainage systems in the road embankment. This type of structures sustain external load using the correlations with the steel wall and engineered backfill materials. Buried flexible conduits made of corrugated steel plates for the coastal road was tested under vehicle loading to investigate the effects of live load. Testing conduits was a circular structure with a diameter of 6.25m. Live-load tests were conducted on two sections, one of which an attempt was made to reinforce the soil cover with the two layers of geo-gird. Hoop fiber strains of corrugated plate, normal earth pressures exerted outside the structure, and deformations of structure were instrumented during the tests. This paper describes the measured static and dynamic load responses of structure. Wall thrust by vehicle loads increased mainly at the crown and shoulder part of the conduit. However additional bending moment by vehicle loads was neglectable. The effectiveness of geogrid-reinforced soil cover on reducing hoop thrust is also discussed based on the measurements in two sections of the structure. The maximum thrusts at the section with geogrid-reinforced soil cover was 85-92% of those with un-reinforced soil cover in the static load tests of the circular structure; this confirms the beneficial effect of soil cover reinforcement on reducing the hoop thrust. However, it was revealed that the two layers of geogrid had no effect on reducing the overburden pressure at the crown level of structure. The obtained values of DLA decrease approximately in proportion to the increase in soil cover from 0.9m to 1.5m. These values are about 1.2-1.4 times higher than those specified in CHBDC.

• Journal of Fashion Business
• /
• v.24 no.3
• /
• pp.85-100
• /
• 2020

Recently, 3D printing technology, which is suitable for small-volume production of many varieties, has become considered a key manufacturing technology in the 4th industrial revolution. However, the nature of 3D printing technology means it is not yet able to be applied to traditional textiles due to Fabric Flexibility. The aim of this study is to investigate Textile Structural Design by finding the optimal yarn thickness for Selective Laser Sintering (SLS) 3D printed structures on geogrid dobby woven fabric that gives the optimal flexibility and tensile strength in the final product. The test results for tensile load strength of the 3D printed test samples, using 1.0mm, 0.8mm, 0.6mm and 0.4mm yarn thicknesses, showed that all were found to be above 250N, this higher than the tensile strength of 180N that is recommended for textile products. Based on these results, the four dobby structural patterns with 3D printing produced had four yarn thicknesses: 1.0mm, 0.8mm, 0.6mm, and 0.4mm. The thinner the yarn, the more flexible the fabric; as such the optimal conditions to produce SLS-based 3D printed textiles with suitable strength and flexibility used a thickness of yarn in the range of 0.4mm to 0.6mm.

• International Journal of Highway Engineering
• /
• v.6 no.2 s.20
• /
• pp.37-45
• /
• 2004

The asphalt concrete pavement takes various advantages of better riding quality, serviceability and easier maintenance. At the same time, it addresses a weak point of the premature failures due to rapid increasement of traffic volume, heavy vehicles and high temperature in summer. It increases the expenditure of maintenance and repair. In order to improve the performance of asphalt pavement avoiding this premature failure, the use reinforcements with geosynthetics have been considered. Geosynthetics are known as an effective reinforcement to restrain fatigue and reflective cracks in asphalt pavements. In this study, a comprehensive parametric study is conducted to capture the efficiency of geosynthetic-reinforcements using viscoelastic properties of the asphalt concrete(AC) layer. The investigated parameters were reinforcement location, AC layer thickness, temperature distribution across the AC layer and modulus of AC and base layer. As a result of observations, that reinforced asphalt concrete could be used effectively for improving resistance against fatigue cracks and permanent deformation. Especially, when a geogrid was placed at the interface between the asphaltic base and the subbase, tensile stress in the horizontal direction was significantly reduced.

• Journal of the Korean Geosynthetics Society
• /
• v.3 no.1
• /
• pp.3-15
• /
• 2004

Geogrid reinforced soil structures with segmental block facing have been increased since 1990's, because of the convenience of installation and the flexible appearance. In this paper, the behavior of the segmental reinforced retaining wall was analysed with the results of field monitoring. The height and length of reinforced wall are 12m and 25m, respectively. The field measurement equipments are horizontal and vertical earth pressure cells, settlement plate, strain gauge, inclinometer, and displacement pin. Based on the field monitoring, the horizontal earth pressure was approximately 0.3times higher than that of the theoretical method and the maximum tensile strength of reinforcement was 26.2kN/m. The displacement of facing wall was 23mm at the point of 7.1m height of the wall and toward the wall facing. The results of the study indicate that the segmental reinforced retaining wall is in a stable condition because of good compaction & reinforcement effects, and long period of construction time. Finally, the computer program of SRWall is very useful tool to design the segmental reinforced retaining wall.