• International Journal of High-Rise Buildings
• /
• v.4 no.4
• /
• pp.249-259
• /
• 2015

This paper introduces the structural design and construction method for the foundation of the TOKYO SKYTREE, a new digital broadcasting tower in Tokyo, which has a height of 634 meters. The surface layer of the ground is occupied by soft soil, thus the foundation of this tower is an SRC continuous underground wall pile, designed and developed to have horizontal rigidity and pull-out resistance. The structural integrity and construction method of the wall pile was verified with an on-site full scale pull-out test concluding a maximum load of 40,000 kN.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.240-247
• /
• 2010

The soil nailing system is becoming common as reinforcement method of slope face in soil. It has application to obtain slope stability method and scaffolding system. It has some troubles when the soil nailing system is applied to the downtown because it could be invaded someone's private area. Thus, in this paper, wedge type removable soil nailing system which can easily remove deformed bar in final excavation step is developed. Field pull-out test is performed to evaluate deformed bars removal and pullout resistance characteristics. According to this result, application of Wedge Type Removable Soil Nailing System is performed.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10b
• /
• pp.983-988
• /
• 2000

Anchoring systems with structural stability and endurance have been one of the most important elements for PSC structures, especially for the structures using non-corrosive FRP tendons. FRP tendons are in increasing use for underground and coastal structures constantly contacted with fresh water or sea water because of their superiority to metallic ones in corrosion-resistance. In this study new non-metallic anchoring system for FRP tendons has been tested and investigated. The newly developed anchoring system utilizes FRP pipes and HEM (Highly Expansive Mortar). The major factors considered in this experiment were expansive pressure of HEM during its hydration and the strength of GFRP(Glass Fiber Reinforced Plastic) Pipe. Anchoring forces of the new anchoring system were investigated from the pull-out testes. The authors analyzed pull-out procedures of the FRP tendons in the various pipe filled with HEM and suggested an improved idea to develop novel non-metallic anchoring system for FRP tendons

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1014-1021
• /
• 2008

Ground anchor should not be used in soft clay, because anchor resistance can not be guaranteed. However, there is a way to increase the capacity of anchors. The pulse powered anchor is an underreamed anchor by using high voltage electrokinetic pulse energy. In this paper, conceptual introduction of the pulse powered anchor was presented. Anchor pull-out tests were performed at the Geotechnical Experimentation Site at Sungkyunkwan University in Suwon, Korea. Data were analyzed in order to verify the performance of pulse powered anchors.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.11c
• /
• pp.1-10
• /
• 1999

In the present study, laboratory pull-out tests with various geogrid shapes are carried out to investigate behavior characteristics of the geogrid. Also, an interface pullout formula is proposed for predicting and interpreting pullout test result. The analytical model is based on the assumption that the reinforcement is linear elastic during the pullout test. And then, maximum pullout force, frictional resistance and active length for each of the grid density ratio are predicted based on the interface pullout formula. The predicted results were compared with those of pullout tests, and showed in general good agreements.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.6
• /
• pp.31-40
• /
• 2005

In this study, a newly modified soil nailing technology which uses bamboo, rich natural material growing in southern areas, is developed to prevent the soil pollution and to overcome the difficulty of excavation near existing structures. Experimental and analytical studies were performed to confirm application possibility of bamboo taking the place of existent reinforcement material, that is steelbar, FRP and etc. In experimental study, strength characteristics of bamboo material were analyzed, and pull-out resistance of bamboo soil nailing system by field pull-out tests was examined. In analytical study, limit equilibrium analysis and displacement analysis were performed, and application possibility of bamboo soil nailing system was analyzed. As the result of this study, bamboo has comparatively good strength and pull-out resistance characteristics. It is expected that bamboo can be used as satisfactory reinforcement material by selecting bamboo with reguired diameter and by controlling the number of bamboo strips. Bamboo is an alternative for the reinforcement of soil nailing system, especially temporary support system in excavation near the existing structures.

• Composites Research
• /
• v.21 no.2
• /
• pp.15-24
• /
• 2008

In this study, shear thickening fluid (STF) filled with rigid nano silica particles was impregnated in plain woven Kevlar fabrics to improve the impact resistance performance. The nano silica particles with an average diameter of 100nm, 300nm, and 500nm were used to make shear thickening fluid to estimate the effect of particle size on the impact behavior of STF impregnated Kevlar fabrics. The yam pull-out and frictional tests were conducted to estimate the effect of impregnated STF on the frictional characteristics. The test results showed that the friction forces were dramatically increased at the STF onset shear strain rates that were measured in preliminary rheology tests. The low speed impact tests were performed using the drop test machine. The results showed that the impregnated STF improved the impact resistance performance of the Kevlar fabrics in terms of the impact energy absorption and the deformation. It has been shown through tests that the impregnated STF affects the interfacial friction which contributes to improve the energy absorption in the Kevlar fabrics. Especially, the impregnation of the STF with the smaller particle size into the Kevlar fabrics showed the better performance in impact energy absorption.

• Journal of the Korean Geotechnical Society
• /
• v.39 no.12
• /
• pp.23-35
• /
• 2023

The Ministry of Agriculture, Food and Rural Affairs has announced design standards for disaster-resilient greenhouses capable of resisting wind speeds with a 30-year frequency to respond to the destruction of greenhouses caused by strong winds. However, many greenhouses are still being maintained or newly installed as conventional standard facilities for the supply type. In these supply-type greenhouses, a small pile called a steel peg is used as reinforcement to resist wind-induced damage. The wind resistance of steel pegs varies depending on the soil environment and installation method. In this study, a correlation analysis was performed between the wind resistance of steel pegs installed in loam and sandy loam, using a soil hardness meter. To estimate the pull-out force of steel pegs based on soil water content and compaction, soil compaction tests and laboratory soil box and field tests were performed. The soil compaction degree was measured using a soil hardness meter that could easily confirm soil compaction. This was used to analyze the correlation between the soil compaction degree in the tests. In addition, a correlation analysis was performed between the pull-out force of steel pegs in the soil box and field. The findings of this study will be useful in predicting the pull-out force of steel pegs based on the method of steel peg installation and environmental changes.

• Advances in concrete construction
• /
• v.8 no.4
• /
• pp.247-255
• /
• 2019

Several reinforced concrete structures that get deteriorated by rebar corrosion are retrofitted using Carbon Fiber Reinforced Polymer (CFRP). When rebar comes in direct contact with CFRP, rebar may corrode, as iron is more active than carbon. Progression of corrosion of rebar in strengthened RC structures has been carried out when rebar comes in direct contact with CFRP. The experimentation is carried out in two phases. In phase I, corrosion of bare steel bar is monitored by making its contact with CFRP. In phase II, concrete specimens with surface bonded CFRP were casted and subjected to the realistic exposure conditions keeping direct contact between rebar and CFRP. Progression of corrosion has been monitored by various parameters: Half-cell potential, Tafel extrapolation and Linear Polarisation Resistance. On termination of exposure, to find residual bond stress between rebar and concrete, pull-out test was performed. Rebar in contact with CFRP has shown substantially higher corrosion. The level of corrosion will be more with more area of contact.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.11c
• /
• pp.95-104
• /
• 1999

In this study, laboratory pull-out tests and finite element modeling are carried out focused on the grid effects of geogrid and the analyses of friction characteristics associated with interaction behaviors of the composite reinforcement composed of geogrid with a superior function in tensile resistance and geotextile with sufficient drainage effects. In addition, drainage effects of the geotextile below geogrid are examined based on the analysis of finite difference numerical modeling. From the present investigation, it is concluded that the geosynthetic composite reinforcement in the weathered granite backfills may possibly be used to achieve effects on both a reduction of deformations and an increase of the tensile resistance, together with drainage effects due to the geotextile.