• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.1
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• pp.5-13
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• 2017

Noise complaints among neighbors in apartment building are mainly caused by floor impact noise that is structure born noise due to occupant induced floor vibration. To control this noise problems many researchers have investigated floor systems and finishing materials. Light-weight impact noise affects by finishing materials, but heavy-weight impact noise induced by heel impacts during normal walking or jumping of children is concerned with structural system and floor vibration. To figure out the characteristics of floor impact noise and transmission of floor vibration due to human activities, vibration tests were conducted in apartment buildings. Impact hammer, heel drop and walking activities were loaded at center of upstairs living room, and accelerations of slabs for both upstairs and downstairs and sound pressure levels for downstairs were measured. The acceleration ratio of transmitted floor vibration to downstairs and human induced vibration in upstairs was between 0.5 and 1.0 according to slab size, wall, and load type. And floor impact noise occurred in the range of natural frequency of slab.

• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.65-73
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• 2006

In these days the floor vibration is beginning to make its appearance of the environmental dispute in dwelling building. Standard floor system are suggested for the settlement of this issue by government. The sound of floor impact sound is needed to secure comfortable quality in housing. Also, it is required an accurate analysis and a proper evaluation for floor vibration. Refine model is necessary for the floor system of housing to analyze accurately the floor vibration. But this refine model is not efficient because it is required so much running time for vibration analysis and it is difficult of modeling of standard floor slab. In this paper, new modeling methods of standard floor slab are proposed for the accurate rigidity evaluation. By using the new modeling method, the accurate vibration response can be obtained and can accurately evaluate the rigidity of standard floor system with resilient materials. Therefore the proposed modeling method is of practical use for vibration analysis of floor system of housing.

• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.83-87
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• 1995

Impact-bouncing height of steel balls dropped from 1m height on various floor materials were measured to evaluate impact-bouncing characteristics depending on floor materials and the effect of these properties on walkability and fatigue of humanbody. Stone and tile finished concrete floor showed the highest bouncing height of around 70%, and soil showed the lowest bouncing height of around 3%. The second highest bouncing height was about 40% which corresponded to terazo finished concrete floor and about twice as high as the bouncing height on concrete floor without finishing. The impact-bouncing height could be lowered to 15~20% by using gum tile on concrete floor. Steel showed similar bouncing height to concrete floor, and wood-based materials showed the second lowest bouncing height next to soil. Among wood-based materials, hardwood species having higher specific gravities showed relatively high bouncing height of 8~24%, softwood species having low specific gravities showed relatively lower bouncing height of 5~18%, and wood composites showed bouncing height of 8~18%. Among all the materials used in this study, wood-based floor materials corresponded to the bouncing height of 10~15% which is considered to be best for humanbody. Surface painting on wood-based materials increased the bouncing height, and the number of bouncing of steel balls after dropping from 1m height increased as the bouncing height increased.

• Structural Engineering and Mechanics
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• v.59 no.5
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• pp.933-950
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• 2016

Decks, interior beams, edge beams and girders are the parts of a steel floor system. If the deck is optimized without considering beam optimization, finding best result is simple. However, a deck with higher cost may increase the composite action of the beams and decrease the beam cost reducing the total cost. Also different number of floor divisions can improve the total floor cost. Increasing beam capacity by using castellated beams is other efficient method to save the costs. In this study, floor optimization is performed and these three issues are discussed. Floor division number and deck sections are some of the variables. Also for each beam, profile section of the beam, beam cutting depth, cutting angle, spacing between holes and number of filled holes at the ends of castellated beams are other variables. Constraints include the application of stress, stability, deflection and vibration limitations according to the load and resistance factor (LRFD) design. Objective function is the total cost of the floor consisting of the steel profile cost, cutting and welding cost, concrete cost, steel deck cost, shear stud cost and construction costs. Optimization is performed by enhanced colliding body optimization (ECBO), Results show that using castellated beams, selecting a deck with higher price and considering different number of floor divisions can decrease the total cost of the floor.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.53-61
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• 2015

This paper reports the test results of the floating floor system used to reduce the floor noise of apartment buildings. Recently, many soft resilient materials placing between the reinforced concrete slab and finishing mortar are used. The resilient material should not only reduce the floor impact sound vibration from the floor but also support the load on the floor. Thus, even if soft resilient materials satisfy the maximum limitation of light-weight impact sound and heavy-weight impact sound, these materials may not support the load on the floor. The experimental program involved conducting sixteen sound insulation floating floor specimens. Three main parameters were considered in the experimental investigation: resilient materials, loading location, and layers of floor. Experimental results indicated that the stiffness of resilient material significantly influenced on the structural behavior of floating floor system. In addition, the deflection of the floating concrete floor loaded at the side or coner of the specimen was greater than that of the floor loaded at the center of the specimen. However, the aerated concrete did not effect on the cracking strength of floating floor system.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.600-603
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• 2003

The floor thickness in residential buildings may not satisfy the floor vibration criteria even though the thickness is determined by the serviceability requirements in current design provisons. Thus it is necessary to develop the procedure to determine slab thickness that satisfies the floor vibration criteria. In this study provide the methods to determine the slab thickness that satisfies the vertical floor vibration criteria for several sizes of flat plate floor system. Randomness inherent in young modulus of concrete and heel drop intensity was accounted. For this purpose Monte Carlo simulation procedure was adopted.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.5
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• pp.476-485
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• 2000

This study numerically investigates thermal comfort in a space cooled by the floor-supply air conditioning system, in which three different supply-return locations, one floor supply-ceiling return and two floor supply-floor returns, are treated. A complementary experiment is peformed to validate the present numerical analysis, and the prediction agrees favorably with the measured data. In the numerical procedure, a simplified model mimicking the inlet flow through the diffuser is developed for efficient simulations. The calculated results show that the ceiling return type is far better in thermal comfort than the floor return ones within the extent of this study, which seems to be caused by effective vertical penetration of the supply air against natural convection. It is also revealed that the arrangement of port locations in the floor supply-floor return system has insignificant effect on the cooling performance. For selecting a proper system, other characteristics including the heating performance should be accounted for simultaneously with the present estimation.

• Korean Journal of Poultry Science
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• v.26 no.3
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• pp.189-193
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• 1999

This experiment was conducted to investigate the effect of floor heating system on housing environment and performance in broiler production. PVC heating pipes(in 25cm spacing) were covered with concrete under the litter. Floor heating system was compared with conventional direct heating system. Each treatment had two replicates of 110 birds each. Litter moisture content was significantly reduced in floor heating system than conventional direct heating system(P〈0.05). Dust concentration was higher in floor heating system because of low litter moisture content. CO$_2$concentration was 2,900ppm and 1,500ppm on the direct heating system and floor heating system, respectively at the age of 1 week. Body weight was significantly higher in floor heating system at 7 weeks of age(P〈0.05). The results of the trial show that floor heating was useful heating system for broiler production.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.598-603
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• 2002

The floor impact noise in apartment buildings has been known as the most sensitively recognized environmental noise. Therefore. inhabitants perceptual evaluation of floor impact noises was investigated by a questionnaire survey. It was found that the respondents perceive the floor impact noises from the upper nor as a constant noise level. However, if there is any child on the upper floor. the respondents felt Its noise as a harshly grating level. It was also found that the larger the respondents house is. the higher their wanted level of noise isolation is. Moreover, it was revealed that the main source of the floor impact noise from the upper floor is a child at the age from six to seven. The results could be used as fundamental data for the research on impact sources and new regulations that fit to Korean perceptual aspects and characteristics.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.5
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• pp.41-47
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• 2004

In this paper, floor impact noise reduction in cruise ship cabin is studied. A mock-up is built by using 6t steel plate, and two identical cabins are made where 25t panel is used to construct wall and ceiling inside the steel structure. Various floating floor systems are tested for which normalized impact noise is measured according to ISO 140-7. In addition, floor SBN (Structure-borne Noise) and floor damping are measured to study the effect of floating floor structure. It is shown that VL(Visco-elastic Layer) is more effective when hard plates are added above the VL.