• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.468-473
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• 2002

The purpose of this study was to present the possible use of a new standard impactor, the rubber ball(so called, impact ball), and to assess its evaluation method as for heavy-weight impact in multi-story residential buildings, Several experiments were carried out to investigate the effect of the impact on noise propagation in reinforced concrete buildings. Then, the noise from the impact ball was psychoacoustically evaluated. The correlation between the L-value evaluation methods and auditory responses was also investigated. Results show that the ball noise is quite similar to the jumping noise. The noise level of ball is even higher than the bang machine noise, although it has much lower impact force. It was also found that L-indexing seems to bge inappropriate for evaluation of ball noise.

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.244-249
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• 2006

Recently, the SCP(Steel Confined Prestressed concrete) composite girders are developed to improve the characteristic such as displacement, vibration, and heavy dead load due to influence of self weight, and inefficiency of steel section of exiting girder-type railroad bridges. It is needed to verify the economical effciency of newly developed SCP composite girder bridge compared with the conventional girder-type bridges. In this paper, LCC analysis for alternative railroad bridges Is performed and its technique based on level of risk(probability of failure) is suggested. From the results, it may be stated that SCP composite girder bridge is more economical than a conventional one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.524-525
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• 2009

Heavy-weight impact noise(HN) is the most irritating noise in Korean apartment houses. It has been proclaimed standard floor system of 210mm thick slab with isolation material in the wall type structure. But this regulation is applied only new construction field and is not considered remodeling field. In general, the LN can be reduced by using isolation material but HN is known as relating with stiffness, strength & boundary condition of slab. Therefore it is difficulty in improving the HN on remodeling field. In this study, We conducted the reinforcement of concrete slab using C.F.S.(carbon fiber sheet), steel plate and steel beam after on-dol with isolation material on the remodeling field. As the test results, It appeared using C.F.S was no improved but using steel plate & steel beam were a little improved on HN.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1243-1246
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• 2006

As remodeling market is growing and peoples' concern on health and well-being is getting high, there is a need to apply environmentally friendly approach to remodeling an apartment houses. But, in point of the impact noise concerned, the thickness of the concrete slab and the limited ceiling height of the remodelling houses are the main constraints to improve the impact noise performance. In order to investigate the effect of the impact noise isolation as structural treatments for the structural elements, heavy-weight impact noise and tapping noise were measured in an remodeling building. As a result, structural strengthening method by H-beam was successful to enhance the impact noise level at about 3 or 4 class by the sound classification system.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.739-745
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• 2004

In reference to conventional line speed-up and improvement railway, accurate assembly of turnout affects traveling quality of turnout area and running safety. Because of heavy weight and a large volume of the long sleepers and car limit, transport and construction of the P.C(prestress concrete) sleeper turnout is the most difficult process. the prerequisite for trouble-free transport of the factory pre-assembled major turnout components is achieved through division of long sleepers. So, in this paper we investigate structural safety of segmented sleeper which is adopted for the first time to improve performance of turnout and, new construction method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.17-20
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• 2008

To develop floor impact sound resilient materials of apartment house effectively, floor impact sound insulation performance test lab. was designed and constructed in T company. Introducing specification and basic performance of this lab. could be helpful in plan and design of another lab. Floor space size of this lab. is $4.2m{\times}5.5m$ and this size is similar with that of living room of usual apartment house's (about $100m^2$) and the height of lab. is 2.4m. Slab thickness is designed by 180mm. Frequency characteristics is similar to general apartment house. Reverberation time of sound receiving room displays 1.26sec in 125Hz by establishing sound-absorbing materials. For light weight impact sound insulation performance of concrete bare floor structure is estimated by $L_{i,AW}\;=\;73$ and for heavy weight is estimated by $L_{i,Fmax,AW}\;=\;50$. Sound pressure level distribution of sound receiving room is ranged very uniformly. With these results, floor impact sound resilient materials could be evaluated and the results could be trusted by comparison tests.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.361-368
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• 2003

As the supply of aggregate needed in the construction site becomes difficult due to preservation of environment and exhaust of aggregate resource, a research for replacement aggregate in shortage is being actively progressed and a copper slag is also a kind of replacing aggregate. To use copper slag as fine aggregate of concrete, many studies are already conducted in each of the advanced countries and in the state of applying these at the site. In the year of 2000 a Korea industrial standard of Copper slag aggregate for concrete was established in our country so that this can be applied in the construction site. This study is to find out whether copper slag is equipped with the physical and chemical requirements for the use in concrete aggregate, and to analyze the dynamic properties of copper slag concrete that replaces 25, 50, 75, 100% of fine aggregate. Copper slag study not only satisfies the using condition of fine aggregate, but also reveals high level of physical property compared to ordinary concrete up to 50% of sand replacement rate. In the future after confirming the durability of concrete using copper slag, it is judged to be advantageous for the preservation of environment to use this as a replacement material for natural aggregate.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.67-74
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• 2017

PURPOSES : In this study, a three-dimensional nonlinear finite element analysis (FEA) model for airport concrete pavement was developed using the commercial program ABAQUS. Users can select an analysis method and set the range of input parameters to reflect actual conditions such as environmental loading. METHODS : The geometrical shape of the FEA model was chosen by considering the concrete pavement located in the third-stage construction site of Incheon International Airport. Incompatible eight-node elements were used for the FEA model. Laboratory test results for the concrete specimens fabricated at the construction site were used as material properties of the concrete slab. The material properties of the cement-treated base suggested by the Federal Aviation Administration(FAA) manual were used as those of the lean concrete subbase. In addition, preceding studies and pavement evaluation reports of Incheon International Airport were referred for the material properties of asphalt base and subgrade. The kinetic friction coefficient between the concrete slab and asphalt base acquired from a preceding study was used for the friction coefficient between the layers. A nonlinear temperature gradient according to slab depth was used as an input parameter of environmental loading, and a quasistatic method was used to analyze traffic loading. The average load transfer efficiency obtained from an Heavy falling Weight Deflectomete(HWD) test was converted to a spring constant between adjacent slabs to be used as an input parameter. The reliability of the FEA model developed in this study was verified by comparing its analysis results to those of the FEAFAA model. RESULTS : A series of analyses were performed for environmental loading, traffic loading, and combined loading by using both the model developed in this study and the FEAFAA model under the same conditions. The stresses of the concrete slab obtained by both analysis models were almost the same. An HWD test was simulated and analyzed using the FEA model developed in this study. As a result, the actual deflections at the center, mid-edge, and corner of the slab caused by the HWD loading were similar to those obtained by the analysis. CONCLUSIONS : The FEA model developed in this study was judged to be utilized sufficiently in the prediction of behavior of airport concrete pavement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.447-455
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• 2019

When constructing LNG storage structures using the cast-in-place method in extreme areas, the construction cost and time may be increased due to the poor working environments and conditions. Therefore, demand for modular energy storage tanks is increasing. In this study, we propose using an SCP module as an alternative for lighter-weight LNG storage tanks. The purpose of this study is to evaluate the feasibility of LNG storage outer tanks by performing bending tests on the thickness of composite steel plate concrete under field conditions. The loads on specimens with thicknesses of 100 mm and 200 mm were linearly increased to the design final loads of 413 kN and 822 kN, respectively. The slope was rapidly changed, and fracture occurred. The two test conditions showed linear behavior until the steel plate yielded, and after an extreme load behavior, sudden yielding of the steel plate yield occurred in the SCP bending test according to the INCA guidelines. The results satisfied the design flexural load and showed the possibility of using the specimens in a modular LNG outer tank. However, it is necessary to evaluate the structural performance of the SCP by performing compression and shear tests in future research.

• Journal of the Korea Concrete Institute
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• v.21 no.1
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• pp.105-116
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• 2009

Reinforced concrete (RC) structures have been most widely used because of their good economic efficiency. However, it is very weak in tensile stresses and difficult to control deflection due to the heavy self-weight of concrete. On the other hand, it is generally known that prestressed concrete structures can be the most effective to overcome the demerits of RC structures by using various tendon lay-out and its amount. In the prestressed concrete members, the inflection points of tendons should be placed effectively for the deflection control and the moment reduction. Therefore, in this study, the equations of tendon profiles are derived in terms of polynomials that satisfy essential conditions of tendon geometries such as inflection points and natural curved shapes of tendons placed in continuous members, from which vertical components of prestressing forces can be also calculated. The derived high order polynomial expression for the distributed shape of the upward and downward forces was transformed to an simplified equivalent uniform vertical force in order to improve the applicability in the calculation of member deflection. The influences of vertical forces by tendons to deflection and moment in a continuous slab were also considered depending on the distance from column face to the location of tendons. The applicability of the proposed method was examined by an example of deflection calculation for the cases of slabs with and without tendons, and the efficiency of deflection control by tendons was also quantitatively estimated.