• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.7
• /
• pp.651-657
• /
• 2010

Previous experimental results performed by many researchers for a couple of decades in South Korea have shown that an absorbing sheet inserted in a conventional floating slab system for thermal insulation or vibration absorption may amplify the vibration of the slab system at specific frequency ranges depending on the material properties of the sheet. The amplified vibration, consequently, results in the heavy weight floor impact noise exceeding the sound level limit for an apartment house, 50 dB. In this study, the amplification mechanism is examined through numerical analysis and a new slab system is proposed to reduce the amplification and control the noise. The new slab system consists of studs connecting the base slab and upper concrete finishing yielding the dramatically increased stiffness of the slab. The numerical simulation is performed to investigate the effect of the slab system with studs on the vibration and noise control. The results show that the performance of the slab is sensitive to the number and location of studs, and the heavy weight floor impact noise can be reduced up to 6~7 dB compared to the conventional slab system at the optimal stud location.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.1156-1156
• /
• 2007

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.24 no.5
• /
• pp.390-398
• /
• 2014

Heavy-weight floor impact noise is directly related to the impact source and floor vibration property. Dynamic properties of the standard floating floor that is used in Korea was investigated using accelerance, acceleration energy spectral density(ESD), and structural modal test. In the standard floating floor, natural frequency was decreased by the finishing mortar mass and the damping ratio was increased. Bang-machine force spectrum acting on the concrete slab can be calculated using inverse system analysis. Impact force acting on concrete slab is changed by interaction of finishing mortar and resilient material. The amplitude of the bang-machine force spectrum was amplified in low frequency range(below 100 Hz), and over 100 Hz was decreased. Changed force spectrum influence to the response of structure vibration, so the heavy-weight floor impact noise level was changed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.05a
• /
• pp.527-528
• /
• 2010

Previous experimental results performed by many researchers for a couple of decades in South Korea have shown that an absorbing sheet inserted in a conventional floating slab system for thermal insulation or vibration absorption may amplify the vibration of the slab system at specific frequency ranges depending on the material properties of the sheet. The amplified vibration, consequently, results in the heavy weight floor impact noise exceeding the sound level limit for an apartment house, 50dB. In this study, the amplification mechanism is examined through numerical analysis and a new slab system is proposed to reduce the amplification and control the noise. The new slab system consists of studs connecting the base slab and upper concrete finishing yielding the dramatically increased stiffness of the slab. The numerical simulation is performed to investigate the effect of the slab system with studs on the vibration and noise control. The results show that the performance of the slab is sensitive to the number and location of studs, and the heavy weight floor impact noise can be reduced up to 6-7dB compared to the conventional slab system at the optimal stud location.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.387-390
• /
• 2005

Finite element method was applied to the vibration analysis of concrete slab system in apartment building. To save the time and cost the 2 dimensional finite element model was proposed. At first, experimental results show that sound peak components to influence the overall level and the rating of floor impact sound insulation were coincident with natural frequencies of the reinforced concrete slab. Second, there is linear relationship between the impact sound pressure level and vibration acceleration level. Third, 2 dimensional finite element model was enough to analyze the vibration analysis of floor structure system.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05a
• /
• pp.199-202
• /
• 2005

KCI 2003 provides minimum thickness of slab that satisfies serviceability to static displacement. Previous study (Han, et al. 2003) showed the several slabs that designed according to minimum thickness criteria had floor vibration problem. In this study, evaluate the floor vibration serviceability of KCI 2003 minimum thickness requirements for 2-way flat plate and propose the minimum thicknesses of 2-way slabs that satisfy floor vibration criteria according to several boundary condition. For this purpose, one degree of freedom model is used and Monte Carlo simulation is performed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.4
• /
• pp.99-106
• /
• 2002

In the composite deck system, beams and deck plates deflect during construction. This lens-shaped deflection may cause problems in the serviceability of a building. Therefore, it should be compensated to be level. Several methods for leveling of floor slab are available, such as (1) increasing stiffness of structural members, (2) propping floor system, (3) cambering beams, (4) pouring additional concrete. In this study, additional weight and volume of concrete for level compensation are examined for various size of floors.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.21 no.9
• /
• pp.805-812
• /
• 2011

This study investigated the characteristics of heavy-weight floor impact sounds of box-frame type structure using 1:10 scale model. Ten types of floor structures(bare slabs and floating floors) were evaluated in terms of dynamic stiffness and loss factor. Floor vibrations and radiated sounds generated by simulated impact source were also measured. The results showed that the bakelite was appropriate for simulating concrete slab in the 1:10 scale model, and surface velocity and sound pressure level of concrete slab measured from the scale model showed similar tendencies with the results from in-situ in frequency domain. It was also found that dynamic behaviors of layered floor structures in the 1:10 scale model were similar to those in a real scale. Therefore, the use of 1:10 scale model would be useful for evaluating the heavy-weight floor impact sound insulation of layered floor structures when the frequency-dependent dynamic properties of each material are known.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.609-613
• /
• 2004

An economic analysis is one of the most dominant factors to determine the project feasibility of super tall building. In economic considerations, it is very important toadopt optimum structural floor systems because these are dependent on both the cost and the duration of construction. The economics affected by structural floor systems are more distinct athigher story. As the story increases, the construction cost of floor system. is accumulated linearly, while the cost of lateral resisting system is increased geometrically. The purpose of this study is to investigate the economical effects of super tall buildings through application of optimum structural floor systems. Three types of structural systems(RC beam-column frame, RC flat plate frame, and Steel frame) of super tall buildings having 50-stories are considered in this study and compared to RC flat plate slab with other systems. Analytical result shows that RC flat plate slab using lightweight concrete ismost effective in both the cost and the duration of construction.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.5 s.98
• /
• pp.604-611
• /
• 2005

The relationship between floor impact sound and vibration has been studied by field measurements, and the vibration modal characteristics have been analyzed. Vibration levels impacted by a standard heavy-weight impact source have been predicted according to the main design parameters using finite element method. Experimental results show that the dominant frequencies of the heavy impact sounds range below 100 Hz and that they are coincident with natural frequencies of the concrete slab. In addition, simple 2-dimensional finite element models are proposed to substitute 2 types of 3-dimensional models of complicated floor structural slabs those by The analytical result shows that the natural frequencies from first to fifth mode well correspond to those by experiments with an error of less than $12\%$, and acceleration peak value iscoincident with an error of less than $2\%$. Using the finite element model. vibration levels areestimated according to the design Parameters, slab thickness, compressive strength, and as a result, the thickness is revealed as effective to increase natural frequencies by $20\~30\%$ and to reduce the vibration level by 3$\~$4 dB per 30 mm of extra thickness.