• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.3
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• pp.176-184
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• 2007

The objective of this paper is to suggest a nonlinear analysis process to predict the structural behavior and strength of composite basement wall member combined with H-Pile. Therefore, the structural behavior of composite basement wall is studied and the special nonlinear characteristics of each elements such as H-Pile, concrete wall, and shear connectors are idealized using ATENA program. Finally, the result is compared with previous test result. Research result shows that there is a good co-relation between analysis and test results even if analysis result has little bit higher initial stiffness than test result. It can be concluded that the nonlinear behavior of composite basement wall is suitably predicted by using the contact element model in ATENA program as shear connector element.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.93-101
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• 2010

When doing underground excavation works for the purpose of constructing large underground structures for a building in the limited space in downtown area, the stability of the adjacent ground must be top priority, and to accomplish this, it is essential to review the retaining wall construction carefully. H-Pile, which has been mainly used as a stress-carrying material in temporary earth-retaining structures, is most likely to be abandoned after completion of the works for the basement exterior wall in relation to contiguous bored piles, so it will result in a waste of material. To improve this situation, Basement Composite Wall where H-Pile and basement wall are compounded, has been developed. This wall is being used most frequently in many local construction sites. In this study, five specimens are made in order to evaluate the shear resistance of the basement composite wall and tested. Test parameter is the composition ratio and wall thickness according to shear connectors. Test result shows that the shear strength is improved when the composite ratio is increased but the magnitude is not much. A formula, which considers the contribution of concrete, web of H-pile as well as flange' effect in calculation of shear strength of composite basement wall, is suggested and used to calculation of the strength of specimens. It is found that there is a good co-relation between test result and the calculated one by the formula.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.7-17
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• 2018

Test bed additional wall combined with PHC-W pile retaining wall has been constructed. To determine the dimensions of test bed additional wall, bending and shear tests of full scale core members of additional wall were tested. Basement additional walls utilizing PHC-W pile retaining wall, which were developed by modifying the cross-section of PHC piles, were classified into the composite additional wall and the non-composite additional wall. Their tests were conducted to obtain bending strength and shear strength of basement additional walls ultilizing PHC-W pile retaining wall. Since bending strengths and shear strengths of the composite additional wall and the non-composite additional wall were similar, it could be confirmed that the non-composite additional wall could be applied instead of the composite additional wall. Full-scale model additional wall was 200 mm thick, thus the thickness of additional wall combined with PHC-W pile retaining wall could be reduced by 100~200 mm.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.207-214
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• 2000

Sand Compaction Pile method is one of the widely used ground improvement techniques at loose sand or soft clay ground in Asian countries. However, due to environmental and economical problems concerning shortage of sand resources alternative materials are needed to substitute sand for SCP. This study is on the applicability of slag as an alternative material SCP. Consolidation and direct shear test are performed for the slag-clay composite specimens to find out the positive effects of consolidation rate and shear resistance of slag reinforced ground. The result shows that slag has similar effects with sand in consolidation and shear resistance behavior in composite ground, which says slag can be used as alternative material of sand for SCP.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.299-306
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• 2001

Crushed Stone Pile(CSP) is one of the ground improvement methods available to loose sand and clayey ground by forming compacted CSP in the weak soil layer. The effects of this method are enhancement of ground bearing capacity, reduction of settlement and prevention of lateral ground movement in cohesive layer, reduction of liquefaction potential in sandy ground. This study performs model tests in 1.0m${\times}$1.0m${\times}$1.0m and 1.5m${\times}$1.5m${\times}$l.2m model tank to observe bearing capacity of CSP treated ground. The area replacement ratio of CSP composite ground varies 20%, 30% and 40% with square grid pattern. After the composite ground was consolidated under pressure of 0.5kg/$\textrm{cm}^2$ and 1.0kg/$\textrm{cm}^2$, load tests were carried out. The results show that ultimate bearing capacity increases with area replacement ratio and the preconsolidation pressure of ground.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.982-989
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• 2005

In this study, a series of laboratory tests based on 'Unit-cell concept' are performed to investigate improvement characteristics of clay ground in sand compaction pile method. Settlement reduction characteristics of composite ground and improvement characteristics of clay part could be qualified. In these procedure, the new strain-compression index($C_{\epsilon}$) of composite ground are adopted to show compressibility of composite ground according to the area replacement ratio, which is similar to the compression index($C_c$) in pure clay ground. Also, using normalization of reduction of water content in composite ground to the initial water content, improvement characteristics of clay part are investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.482-489
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• 2009

Various model piles with different sections such as reinforced concrete, steel, steel-concrete composite without rebar and steel-concrete composite with rebar were made, and vertical load test was conducted using a large scaled UTM(Universal Test Machine) to evaluate Young's modulus and ultimate load of the model piles. Based on the tests, ultimate load of steel-concrete composite pile is 31% greater than the sum of it of reinforced concrete pile and it of steel pile. This is caused that ultimate load and Young's modulus of inner concrete increase due to confining effect by outer steel casing. Variation of ultimate load is also insignificant depending on the ratio of length to diameter(L/D), therefore bucking has not an effect on change of ultimate load in case of the L/D below 10.

• Journal of the Korean GEO-environmental Society
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• v.12 no.8
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• pp.59-67
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• 2011

The interaction of the ground deformation and composite piles, which is made of fiber glass, was analyzed for the effective pile application under vertical loads. This study was performed to conduct experimentation test and propose the material characteristics of the new type concrete injection circular FRP pile for the improvement of the defect of CFFT-Concrete composition piles and FRP-Concrete composition piles(FRP reinforced column direction). Additionally, in order to analyze the behaviour characteristics of composite pile and steel pile the numerical analyses were carried out.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.227-234
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• 2004

Sand compaction pile (SCP) method is composed of compacted sand pile inserted into the soft clay deposit by displacement method. SCP-reinforced ground is composite soil which consists of the SCP and the surrounding soft soil. When a surcharge load is applied on composite ground, time-dependent behavior occurs in the soft soil due to consolidation according to radial flow toward SCP and stress transfer also takes place between the SCP and the soft soil. This paper presents the numerical results of cylindrical composite ground that was conducted to investigate consolidation characteristics and the stress transfer mechanism of SCP-reinforced composite ground. The results show that the consolidation of soft clay has a significant effect on the stress transfer mechanism and stress concentration ratio of composite ground

• Journal of the Korea Concrete Institute
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• v.29 no.4
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• pp.353-360
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• 2017

The objective of this study is theoretical and empirical evaluation of the flexural performance of concrete filled pretensioned spun high strength concrete pile with ring type composite shear connectors (CFP pile). The specimens are comprised of standard CFP pile, PHC pile+composite shear connector+filed concrete (CFP-N-N), standard CFP pile with $1^{st}$ reinforcements (H13-8ea), and standard CFP pile with $1^{st}$ and $2^{nd}$ reinforcements(H19-8ea). Flexural performance evaluation results showed that the ductility is improved with increased steel ratio, which leads to the increased maximum load by 46.4% (with $1^{st}$ reinforcement) and 103.9% (with $1^{st}$ and $2^{nd}$ reinforcements) compared to standard CFP ( CFP-N-N). Comparing with the predicted ultimate limit state values of the CFP pile design method and the experimental results, the design method presented in this study is reasonable since safety factor of 1.23 and 1.40 times for each reinforcement step are secured.