JPH068564B2 - Soundproof floor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a soundproof floor provided with a device for reducing floor impact sound related to the upper and lower parts (boundary floor) of a living room in a building in construction.

[Conventional technology]

Conventionally, various soundproof floor construction methods have been attempted to construct a floating floor that is vibration-supported on a floor slab (hereinafter abbreviated as “slab”) of a building frame for the purpose of reducing floor impact noise. It is effective for the floor impact sound in the middle and high range due to the lightweight impact source, but is not sufficiently effective for the floor impact sound in the low temperature range due to the heavy impact source. The reason is that the floor impact sound in the low temperature range is mainly caused by the low-order vibration mode of the slab excited by the heavy impact source,
This is because the conventional soundproof floor construction method using a floating floor was almost ineffective for this vibration mode. As a floor impact noise reduction measure targeted for this slab vibration mode, conventionally, in order to strengthen the rigidity of the slab, increase the thickness of the slab,
A method of increasing the number of beam beams or using a hollow slab or a ribbed slab has been adopted.

[Problems to be Solved by the Invention]

However, any significant effect of these methods was accompanied by a significant increase in weight per unit area of slab. This increase in weight immediately affects the structural structure of the building, resulting in an increase in the weight of the entire building and an increase in cost, and it is often difficult to deal with it as a post-measure.

The present invention is intended to solve the above problems.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides an upper floor which is supported on the slab at a space around the slab having a high rigidity or at a node of a vibration mode of the slab that is difficult to vibrate, A dynamic vibration absorber was attached to the upper floor side of the underfloor space. The upper floor may be a floating floor that is vibration-proofed and supported via a vibration-proof rubber or the like.

[Work]

This is because the damping effect when added to the resonance system, which is a dynamic vibration absorber, acts to make the dynamic vibration absorber antiresonant with respect to the resonance of a certain mass system, and suppresses the impedance reduction at the resonance of a certain resonance system. . The present invention has applied this action to suppress the impedance decrease at the time of resonance of the vibration mode of the slab.

That is, since the slab can be regarded as a series circuit composed of elements of an equivalent mass Ms, an equivalent spring constant Ks, and an equivalent resistance Rs that are globally connected to an infinite impedance, its impedance zs is the resonance natural frequency fs of equation (1). And becomes the minimum.

On the other hand, the dynamic vibration absorber has a mass Md connected to Ms, a spring constant Kd,
Since it can be regarded as a parallel circuit composed of the elements of the resistance Rd, its impedance Zd becomes maximum at the anti-resonance natural frequency fd of the equation (2).

Therefore, if the elements of the dynamic vibration absorber are adjusted so that fd = fs, the impedance of the slab (Zs
+ Zd) can be Zs << Zs + Zd at the resonance natural frequency fs, so that the vibration of the slab is suppressed and the sound emitted from the slab is also suppressed.

Further, according to the present invention, the dynamic vibration absorber is provided below the floor of the upper floor supported by a space above the slab so as not to disturb the floor of the living room. In addition, the support point of the upper floor should be installed at the periphery of the slab or at the node of the vibration mode so that the impact excitation force applied to the upper floor is not directly applied to the antinode position of the vibration mode where the slab easily vibrates. I am doing it.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an example in which the present invention is applied to a floating floor of a building having a reinforced concrete structure, 1 is a slab, 2 is a beam or wall of a frame supporting the slab 1 and supporting the slab 1, and 3 is an underfloor space 6. A floor plate of the upper floor, which is supported near the beams or walls 2 by joists 4a, 4b and a vibration-proof rubber stand 5. Here, the joist 4a must have a length and rigidity sufficient to bridge the fulcrums at both ends of the slab 1. The joists 4b are members that connect and reinforce the joists 4a.

In this state, when a person jumps on the floor plate 3 now, the impact exciting force 9 is applied to the floor plate 3 and the joists 4
Slab 1 through a, 4b, anti-vibration rubber stand 5, and underfloor space 6
Transmitted to. At this time, since the exciting force generally has a wide vibration power spectrum, the resonance natural frequency fs of the slab 1 is excited and the radiated sound 10 having fs as a main component is emitted downstairs to give an uncomfortable feeling.

The dynamic vibration reducer has a function of reducing the radiated sound 10, and is constituted by the additive load 7 shown in the figure, a spring base 8 having a spring and a resistance element, and a support 11. The additional load 7 provides a mass Md and is preferably made of a material having high rigidity, such as a concrete block or a steel piece. The spring base 8 provides an appropriate spring constant Kd and resistance Rd and supports the additional load 7. A vibration-proof rubber, metal spring, or other vibration-proof base is suitable. The resistance Rd is a Coulomb friction damping resistor, viscous damping resistor, structural damping resistor, or various dampers,
Generally included in the spring mount 8, but may be attached separately. The support 11 is a tool for supporting the spring base 8, and is preferably made of a sufficiently robust material such as a steel piece.
It is fixed to b.

By mounting the dynamic vibration absorber in this way, the vibration force transmitted from the floor plate 3 of the floating floor shaken by the impact vibration force 9 to the slab 1 through the joists 4a and 4b and the underfloor space 6 is a term of action. The radiation sound 10 emitted from the slab 1 is reduced because it is controlled by the action described in (1).

FIG. 2 is an example showing the effect of the dynamic vibration absorber confirmed by the experimental slab.

The structure of the test piece is the same as that shown in Fig. 1, but for convenience of the experiment, the beam for fixing the slab and its periphery was made of precast concrete.

The two dynamic vibration absorbers used in the experiment had a mass Md of 32 kg, and the mass Md was supported by a vibration-proof rubber base composed of the spring constant kd and the resistance Rd. Since the target resonance natural frequency fs is about 40 Hz, the anti-resonance natural frequency fd is also about 4
It was adjusted to 0 Hz.

The figure shows the measured vibration acceleration level on the slab when the tires are shaken on the upper floor, and the peak of the resonance natural frequency fs is significantly reduced by the installation of the dynamic vibration absorber. When vibration force is applied, it means that the floor impact sound in this area is reduced.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The present invention can control the vibration related to the slab and reduce the floor impact sound only by installing a dynamic vibration absorber under the floor of the upper floor having a space between the floor and the slab. Further, since the dynamic vibration reducer is attached to the underfloor space, it does not become a nuisance or an obstacle.

INDUSTRIAL APPLICABILITY The present invention can control not only the floor impact sound but also the vibration of the slab due to external vibration other than the floor impact excitation force transmitted to the slab, and therefore the external vibration adversely affects the occupants above and below and the precision machinery. It is possible to reduce the vibration and radiated sound that cause.

The present invention, since the weight increase given to the slab is generally only the added load of the dynamic vibration absorber, it is slight, without applying a load bearing member to the body structure like the conventional slab vibration control method,
Moreover, since it directly and effectively affects the natural frequency of the target slab, it is simple, inexpensive and high-performance.

If the upper floor of the present invention is a floating floor by inserting a vibration-proof rubber or the like into its support portion, the sound-proof / vibration-proof performance against floor impact noise and external vibration can be further improved.

[Brief description of drawings]

FIG. 1 illustrates an embodiment of the present invention. (A) is a partially cut plan view, (b) is a sectional view taken along line AA of (a), and FIG. The experimental results showing the basic effect of the above, and the vibration acceleration level with respect to the center frequency of the 1/3 octave band of the slab when the upper floor of the specimen is subjected to shock excitation. 1 ... Slab, 2 ... Beam or wall, 3 ... Floor plate of upper floor, 4a
... joists (for supporting points), 4b ... joists (for joining), 5 ... anti-vibration rubber stand, 6 ... underfloor space, 7 ... additional load, 8 ... spring stand, 9
… Impact shock force, 10… Radiated sound, 11… Bearings.

Front page continuation (72) Inventor Masanori Tano 2-191-1 Tobita, Chofu City, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (56) Reference JP 62-170658 (JP, A) JP 62- 182358 (JP, A) Actual development Sho 59-187967 (JP, U) Japanese Patent Publication 4-64385 (JP, B2)

Claims (1)

[Claims] 1. A space is provided on a floor slab of a building frame,
An upper floor that was supported at the periphery of the floor slab or at the position of the vibration mode node of the floor slab was provided, and on the upper floor side of the underfloor space, adjusted to match the natural frequency of the floor slab, A soundproof floor characterized by being equipped with a dynamic vibration absorber consisting of a combination of additional load, spring and resistance.