• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.956-963
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• 2002

In a recent construction industry, cable supported structures such as a cable-stayed bridge or space stadium have been increasingly constructed according to rapidly upgrade their related technologies. Generally stay cables as a critical member need to be rearranged for being satisfied with design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted on existing stay cables. In this study, cable vibration tests were tarried out to evaluate the cable tension forces comparing with theoretical and practical formulas. Using the measured frequencies obtained from free vibration and Impulsive tests, an accuracy of the estimated tension forces is confirmed according to use the first single mode only or higher multiple modes.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.6 s.111
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• pp.574-581
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• 2006

Flat plate slab systems are more economical rather than reinforced concrete frame systems because flat plate slab system reduces story height. Furthermore flat plate systems are more popularly needed in construction practice due to flexibility of plan. Korean Concrete Provisions 2003 provide the minimum thickness of the slab that satisfies serviceability requirement to the static displacement. However, floor thickness in residence buildings may not satisfy the floor vibration criteria although the thickness satisfies the serviceability requirements in current design provisions. This study estimates the dynamic properties of floor vibration for existing flat plate slabs, and proposes the slab thickness satisfying the floor vibration criteria. The dynamic response analysis using finite element method and reliability analysis are carried out for this Purpose.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.214-219
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• 2008

Recently, railway has been pointed to the efficiency of transportation, rapid transit, and comfortable train ride. In the case of domestic situation, both rapid transit railway and existing railway have been operated in higher speed and the construction of railway near the city building has been increased as well. Because of the rapid transit system and heavy railway, the noise and vibration of railway has been increased so that the strong standards in terms of environmental matter should be required. Therefore, the solution to avoid environmental matters becomes one of the most important factor in constructing railway. In this study, floating slab system which is one of the solution to avoid noise and vibration in railway has been introduced, and the foreign technology and the trend of this business has been investigated. In addition, the method of conceptual design and construction of floating slab system according to the isolator has been introduced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.359-362
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• 2005

Road traffic noise level and railway noise level are important factors on apartment inhabitant's comforts. The measurement methods which noted by Ministry of Construction & Transportation(MOCT) and Ministry of Environment(ME) are used for measurement of exterior noise at apartment houses. But these methods are out of date because the height of apartment houses have increased dramatically and owing to the sampling methods of the measurement time interval, rating values are induced differently due to sampling methods. In this study, the sound level of each floor of apartment houses is measured and compared. And rating value due to sampling methods are compared. As a result, the KS outline of 'Field Measurement of Exterior Noise at Apartment Housess' is suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.203-207
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• 2014

According to the advanced study, Increase of ceiling air space could cause increase of floor impact sound by air-spring effect. So in this research, we studied the increase of floor impact sound caused by ceiling air space in apartment buildings. At first, we evaluated the change of floor impact noise in the condition of with or without ceiling air-space. And then we installed perforated ceiling systems and glass wool at ceiling area. we expected that perforated ceiling systems could prevent air-spring effect in ceiling space. As a result, ceiling air space caused increasement of floor heavy impact noise about 2~4dB. But perforated ceiling & sound-absorbing materials system could give us reduction of heavy floor impact noise about 3dB. So this systems could be a good alternative to obey national regulations, because it can reduce heavy impact noise additional to floating floor systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.358.1-358
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• 2002

Recently a number of social surveys on community response to environmental noises have been conducted. Since standardized noise annoyance scales were needed to compare the results from various areas, ICBEN(International Commission on Biological of Noise) Team 6 planned a international joint study and constructed comparable standardized noise annoyance scales using the same method. In Korea the survey was conducted in four areas such as Seoul, Taejon, Honam and Yongnam. 100 subjects participated in each area approximately. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.121-126
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• 2002

In a recent construction industry, cable supported structures such as a cable-stayed bridge or space stadium have been increasingly constructed. Generally the stay cables as a critical member should be adjusted to be satisfied with the design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted to the existing stay cables. In this study, cable vibration tests were carried out to estimate the cable tension forces comparing with theoretical and practical formulas. From the measured frequencies obtained from free vibration and impulsive tests, the accuracy of 1he estimated tension forces is confirmed according to use only the first single mode or higher multiple modes.

• Explosives and Blasting
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• v.15 no.2
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• pp.44-52
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• 1997

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.1 s.106
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• pp.19-26
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• 2006

The test blasts were carried out by detonating some single blastholes at two upper sites of the underground storage cavern for the crude oil. One was performed at the entrance site of the construction tunnel and the other at the middle area of the underground storage cavern. Based on the blast-induced nitration measured by the test blasts, we suggested the propagation equations of blasting vibration that were capable of estimating the peak particle velocity. In addition, in order to assess the stability of the adjacent ground storage tank, we did the frequency analysis and the response spectrum analysis with the particle velocity-time history and the particle acceleration-time history that were measured by the test blast carried out on the entrance site of the construction tunnel. In result, it was predicted that the displacement on the highest part of the tank shell was less than the allowable displacement.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.71-80
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• 2013

Before and after the test constructions, and after an 11-month hiatus from the pilot pile installations, the in-situ tests (CPT, SPT) were carried out at the ground adjacent to the noise- and vibration-free screw concrete piles installed by 2 kinds of construction methods (i.e., the toe-jetting shoe type, the pre-digging type). In the toe-jetting shoe type construction methods, after construction, the soil strength within 3.5D (where, D = pile diameter) from the pile center decreased greatly by about 46% of the original ground and, after an 11-month hiatus, a strength recovery adjacent to the piles appeared about 71% of the original ground. In the pre-digging type construction methods, a strength recovery adjacent to the piles appeared 100% of the strength of the original ground.