• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.1
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• pp.161-168
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• 2001

The use of composite members to improve the compressive strength of steel structure is a common practice these days and its efficiency has already been proved by several researches and experiments. The result of concrete filled circular tubular(CFCT) stub column tests is introduced in this paper. The main parameter of this test is the ratio of diameter to thickness of circular hollow section. From the test results, the effect of concrete filled in steel tube on the ultimate strength, the deformation capacity and initial stiffness are discussed. The purpose of this paper is to investigate the effect of various parameters and evaluate the compressive strength of confined concrete. It would contribute to a better understanding of CFT structure, further laboratory experimentations are needed for better accurate estimation on its effect.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.3
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• pp.212-222
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• 1998

In several structural problems, the low concrete strength of compression members has the severest influence on the structural safety. However, the repairing and strengthening techniques for compression members are not established and evaluated. This study aimed to develop and evaluate the rehabilitation techniques to obtain proper structural strength of wall with low concrete strength. The specimens with low strength of concrete were retrofitted with commonly using section increase method and epoxy bonded glass fiber techniques. The tests were executed to failure under concentric and eccentric loads. In this paper, the structural behavior and failure modes were investigated to evaluate the strengthening effects of walls subjected to compression and out-of-plane bending.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.4
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• pp.161-167
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• 2001

By means of analyzing the problems in monitoring plan, design, installation, operation based on maintenance monitoring system installed in subway tunnel section, the improved methods of were proposed for applying to subway monitoring maintenance effectively in the future. The choice of the better monitoring system, the operating method of monitoring system, the confidence and continuity of maintenance monitoring, the performance of responsible monitoring supervision in the phase of the planning of monitoring and design were proposed. The problem and developed plan in the different monitoring systems, the calibration and correction of monitoring system, the analysis for the results and plan for maintenance in the phase of installation of monitoring system and operation were also proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.4
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• pp.119-127
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• 2002

This paper presents a study of the behaviour of bolted circular flange joints in tubular structures. In the tests on nine circular flange joints, different tension forces was applied to the joints and bolt strains, displacements and strains in the joints have been measured. Bolt strain, contact force(prying force) between flanges and stress distribution in a joint have been studied. Different methods used for the design of circular flange joints are described.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.2
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• pp.151-158
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• 2000

A study on the strength of steel tubular column filled with concrete under cocentrically compressed load is presented in this paper. This paper is structured as follows. The first section briefly discusses the M-N relationship formula derived for CFT, highlighting the additional moment effect. Next, the simple superposed method used to generate the strength formula of CFT loaded concentrically is described. In the final portion of this paper, the presented formula is compared to experimental data reported. The applicability of CFT strength formula presented here is limited somewhat by scope of concrete strength but can predict the strength of CFT simply and rapidly. The objective of this paper is to approach the strength of CFT theoretically and to examine the feasibility of presented formula.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.187-194
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• 1999

In this study, a series of items on the safety and stability of cracked main structure in subway are investigated and analyzed. Cracks due to dry contraction under the construction can be found when a tensile stress of cross section is higher than tensile strength at a value of coefficient of dry contraction $200{\times}10^{-6}$. It is concluded that there is no problems when load carrying capacity, that is, an ability of resisting loads of structure is enough in this analytical model. Also, it is concluded that this model has a desirable serviceability because a width of bending crack is lower than allowable one.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.165-174
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• 2004

This study is about a horizontal load test of buoyance anchor installed in the section where underground water level happens in the depth of 5m under the ground when the ground is excavated, because the section as a excavation section of high speed railway ${\bigcirc}{\bigcirc}$ station is near a rivers and because the section always has a reservoir of full water level on the left. Therefore, in this study we will appraise the long-term stability of the structure permanently being taken buoyance by the underground water level, through the spot test of the buoyance anchor installed in the section where underground water level happens. For that, Bar Type anchor is used, which can get enough pulling-out force by a method to resist buoyance by using friction force against the ground by high strength steel rod or steel wire. Anti-buoyance anchor is installed on the bottom slab of underground structure being taken horizontal force by the braking and accelerating of high speed train. And, It is aimed to analyze and grasp the review result of stability for the horizontal force that happens at the parking and stopping of high speed train, by executing horizontal load test for the grasping of the movements characteristic of buoyance anchor.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.2
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• pp.33-44
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• 2013

Although many studies have been performed for the structural details of orthotropic steel deck, most of them were focused on the trough rib of standard type, but not for orthotropic steel deck with longitudinal rib of open section used at beginning of the deck. In order to investigate the cause of fatigue crack for orthotropic steel deck bridge serviced 31 years with longitudinal rib of open section, in this study, the behavior characteristics of target structural details were analyzed based on measurement data under real traffic condition. Also the typical loading truck passing the target bridges was estimated with the structural analysis detailed, and the stresses and deformation patterns of target structural details were analyzed by performing the detailed structural analysis. Based upon the analysis, retrofitting methods of the fatigue crack were suggested and its validation was examined. From this study, it was clarified that fatigue crack of longitudinal rib with open section were affected with the stress increment by shear deformation in the rib and the occurrence of alternative stress due to moving vehicle. In addition, it was known that it is important to perform fatigue design reflected the local behavior of the structural details.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.15-20
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• 2005

Defects of dam body which can be induced in seepage or leakage procedure can directly affect dam safety. Therefore, a proper inspection method should be carried out in the first place to find out their positions and sizes, After that, some reinforcement works such as grouting and the corresponding assessment could be taken in a proper way. The dam(center core type earth dam) issued in this study has been in need for intensive diagnosis and reinforcement work, because a lot of slumps similar to cracks, seepage and some boggy area have been observed on the downstream slope. High resolution seismic reflection method was performed on the crest profile twice before and after grouting work(Aug. 2001 and Nov. 2004) aimed at the dam inspection and the assessment of grouting efficiency as well. To enhance the data resolution, P-beam energy radiation technique which can reduce the surface waves and hence to reinforce the reflection events was used. Strong reflection events were recognized in the stack section before grouting work, It seems that the events would be caused by e.g. horizontal cracks with a considerable aperture, Meanwhile such strong reflection events were not observed in the section after grouting. That is, the grouting work was dear able to reinforce the defects of dam body. Hence, the section showed an well arranged picture of dam inner structure. In this sense, seismic reflection method will be a desirable technique for dam inspection and for monitoring dam inner structure as well.

• Journal of the Korean Geophysical Society
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• v.8 no.1
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• pp.1-6
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• 2005

Defects of dam body which can be induced in seepage or leakage procedure can directly affect dam safety. Therefore, a proper inspection method should be carried out in the first place to find out their positions and sizes. After that, some reinforcement works such as grouting and the corresponding assessment could be taken in a proper way. The dam(center core type earth dam) issued in this study has been in need for intensive diagnosis and reinforcement work, because a lot of slumps similar to cracks, seepage and some boggy area have been observed on the downstream slope. High resolution seismic reflection method was performed on the crest profile twice before and after grouting work(Aug. 2001 and Nov. 2004) aimed at the dam inspection and the assessment of grouting efficiency as well. To enhance the data resolution, P-beam energy radiation technique which can reduce the surface waves and hence to reinforce the reflection events was used. Strong reflection events were recognized in the stack section before grouting work, It seems that the events would be caused by e.g. horizontal cracks with a considerable aperture. Meanwhile such strong reflection events were not observed in the section after grouting. That is, the grouting work was dear able to reinforce the defects of dam body. Hence, the section showed an well arranged picture of dam inner structure. In this sense, seismic reflection method will be a desirable technique for dam inspection and for monitoring dam inner structure as well.