• Title/Summary/Keyword: Floor Impact noise

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Floor Impact Noise Characteristics Depending on the Experimental Conditions Using Impact Ball (실험조건에 따른 임팩트 볼의 바닥충격음 변화 고찰)

  • Lee, Won-Hak;Haan, Chan-Hoon
    • The Journal of the Acoustical Society of Korea
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    • v.30 no.2
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    • pp.92-99
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    • 2011

  • In Japan, bang machine has been considered to have problems about not only the impact force and frequency response which are different from the real impact sources such as children's jumping and running, but also damage in the wooden structure housing. Therefore, a new impactor for lower impact force to prevent demage in wooden structure housing was developed. The impact ball was adopted as the second standard impact source in JIS A 1418-2 and ISO 140-11. In the present study, floor impact sounds generated by impact ball with drop heights in four floors of mock-up building of Building Research Institute (BRI) similar to typical Japanese wooden structure housing were investigated and also compared to jumping sound. The results show that Impact ball sound dropped at 10 cm to 30 cm was most similar to jumping sound. And The impact sound levels at 250 and 500 Hz were more sensitive to drop height than other lower frequencies. The error that may occur from the difference of height of 10 cm up and down based on the standard drop height caused by the impact ball operated by human hands was approx. 1 dB or less only in its value of characteristic, but it must be carefully taken into Impact ball in the Korea Standard.

  • https://doi.org/10.7776/ASK.2011.30.2.092 인용 PDF KSCI

A Physical Properties of Lightweight Foamed Concrete According to Lightweight Aggregate Types and Foaming agent Types (경량골재와 기포제 종류에 따른 경량기포 콘크리트의 물리적 특성)

  • Kim, Ha-Seog;Lee, Sea-Hyun;Sun, Jung-Soo;Kim, Jin-Man
    • Journal of the Korea Concrete Institute
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    • v.28 no.4
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    • pp.435-444
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    • 2016

  • In Korea, approximately 48% of all households live in apartments, which are a form of multi-unit dwellings, and this figure increases up to 58%, when row houses and multiplex houses are included. As such, majority of the population reside in multi-unit dwellings where they are exposed to the problem of floor impact noise that can cause disputes and conflicts. Accordingly, this study was conducted to manufacture a high-weight, high-stiffness foamed concrete in order to develop a technology to reduce the floor impact noise. For the purpose of deriving the optimum mixing ratio for the foamed concrete that best reduces the floor impact noise, the amounts of the foaming agent, lightweight aggregate and binder were varied accordingly. Also, the target characteristics of the concrete to be developed included density of over $0.7t/m^3$, compressive strength of over $2.0N/mm^2$ and thermal conductivity of under 0.19 W/mK. The results of the experiment showed that the fluidity was very excellent at over 190 mm, regardless of the type and input amount of foaming agent and lightweight aggregate. The density and compressive strength measurements showed that the target density and compressive strength were satisfied in the specimen with 50% foam mixing ratio for foamed concrete and in all of the mixtures for the lightweight aggregate foamed concrete. In addition, the thermal conductivity measurements showed that the target thermal conductivity was satisfied in all of the foamed concrete specimens, except for VS50, in the 25% replacement ratio case for Type A aggregate, and all of the mixtures for Type B aggregate.

  • https://doi.org/10.4334/JKCI.2016.28.4.435 인용 PDF KSCI