JPS63201258A - Soundproof floor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soundproof floor provided with a device for reducing floor impact noise related to the space between the upper and lower floors of living rooms in a building (boundary floor) in architecture.

[Conventional technology]

In the past, various soundproof floor construction methods have been attempted in which a floating floor with anti-vibration support is constructed on top of the floor slab (hereinafter abbreviated as "slab") of the building frame in order to reduce floor impact noise. Although it is effective against floor impact sounds in the medium and high range caused by lightweight impact sources, it is not sufficiently effective against floor impact sounds in the low range caused by heavy impact sources. The reason for this is that low-frequency floor impact noise is mainly caused by the low-order vibration mode of the slab excited by the weight impact source, and conventional soundproof floor construction methods using floating floors are designed to deal with this vibration mode. This is because it was almost ineffective. Conventional measures to reduce floor impact noise targeting this vibration mode of the slab include increasing the thickness of the slab in order to strengthen the rigidity of the slab.
The methods used were to increase the number of beams, or to use hollow slabs or ribbed slabs.

[Problem that the invention seeks to solve]

However, obtaining any significant effect with these methods was accompanied by a considerable increase in the weight per unit area of the slab. This weight increase immediately affects the building frame structure, resulting in an increase in the weight of the entire building and an increase in costs, which is often difficult to deal with, especially with post-event measures.

The present invention aims to solve the above-mentioned problems.

Means for Solving Problem C] In order to achieve the above object, the present invention installs a dynamic vibration absorber consisting of a combination of an added load, a spring, and a resistance at the antinode position of the problematic vibration mode on the slab. However, this allocation effect is applied.

In this case, if a dynamic vibration absorber is installed on a single slab,
This becomes a nuisance and impedes its function as a living room floor. Furthermore, if the impact excitation force is applied directly to the vicinity of the dynamic vibration absorber, its damping effect will be less effective.

In order to solve these problems, the present invention provides an upper floor that is supported at the periphery of the slab with high rigidity or at the nodes of the vibration mode of the slab that are difficult to vibrate, with a space above the slab. A dynamic vibration absorber was installed above the slab in the underfloor space at the antinode of the vibration mode of the slab. It is further preferable that this upper floor be a floating floor that is vibration-proof and supported via vibration-proof rubber or the like.

[For production]

The damping effect when a dynamic vibration absorber is added to a certain resonant system is because the dynamic vibration absorber works to anti-resonate with respect to the resonance of a certain mass point system, and suppresses the drop in impedance when a certain resonant system resonates. .

The present invention applies this effect to suppressing a drop in impedance when the vibration mode of the slab resonates.

That is, the slab is globally connected to an infinite impedance with an equal mass Ms, an equivalent spring constant Kg, and an equivalent resistance R.
Since it can be regarded as a series circuit consisting of elements of s, its impedance Zs becomes minimum at the resonance natural frequency fs of equation (1).

fs=(1/2π)・Jfu possible・−−−−−−・−(l
) On the other hand, the dynamic vibration absorber can be regarded as a parallel circuit consisting of the mass connected to Ms, the spring constant Kd, and the resistance Rd, so its impedance Zd becomes maximum at the anti-resonant natural frequency fd of equation (2). .

fd=(1/2π)・417th edition ・−・・−−−−−−
-(2) Therefore, if the elements of the dynamic vibration absorber are adjusted so that fd = fs, the impedance (Zs + Zd) of the slab on which the dynamic vibration absorber is installed will be Zs << Zs + Zd at the resonance natural frequency fs. As a result, the vibration of the slab is suppressed, and the sound emitted from the slab is also suppressed.

Further, in the present invention, the dynamic vibration absorber is installed under the upper floor supported above the slab with a space so that it does not interfere with the floor of the living room. In addition, the support points of the upper floor should be installed at the periphery of the slab or at the nodes of the vibration mode so that the impact excitation force applied to the upper floor is not directly applied to the antinode of the vibration mode where the slab is likely to vibrate. It's Nishide.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

Figure 1 shows an example in which the present invention is applied under a floating floor of a building with a reinforced concrete structure, where 1 is a slab, 2 is a beam or wall of the frame that is connected to the slab 1 and supports the slab 1, and 3 has an underfloor space 6. The floorboard of the upper floor is supported near the beam or wall 2 by joists 4a, 4b and a vibration-proof rubber stand 5. Here, the joist 4a must have sufficient length and rigidity to allow the frame to pass between the support points at both ends of the slab 1. The joists 4b are members that connect and reinforce the joists 4a.

In this state, if a person jumps on the floorboard 3, the impact excitation force 9 will be applied to the floorboard 3, and the joists 4a
, 4b, is transmitted to the slab 1 via the vibration-proof rubber stand 5 and the underfloor space 6. At this time, since the excitation force generally has a wide vibration power spectrum, it excites the resonant natural frequency fs of the slab 1, and radiates sound 10 whose main component is fs to the floor below, giving an unpleasant feeling.

The dynamic vibration absorber has the function of reducing this radiated sound 10, and is composed of an additional load 7 shown in the figure and a spring base 8 having spring and resistance elements. The additional load 7 provides mass Md, and is preferably made of a highly rigid material, such as a concrete block or a steel piece. The spring base 8 has an appropriate spring constant Kd.
A vibration isolating table made of vibration isolating rubber, a metal spring, etc. is suitable for providing the resistance Rd and supporting the additional load 7. The resistor Rd is a Coulomb friction damping resistor, a viscous damping resistor, a structural damping resistor, or various dampers, and is generally included in the spring base 8, but may be attached separately. The location for installing this dynamic vibration absorber is effective at the antinode of the vibration mode of the resonance natural frequency fs of the slab 1.

By installing the dynamic vibration absorber in this way, the excitation force transmitted from the floorboard 3 of the floating floor, which is excited by the impact excitation force 9, to the slab l via the joists 4a, 4b and the underfloor space 6 can be reduced in terms of action. Since it is controlled by the described action, the radiated sound 10 emitted from the slab I is reduced.

FIG. 2 is an example showing the effect of a dynamic vibration absorber confirmed using an actual slab.

The specimen is a rectangular reinforced concrete slab measuring 150 x 3000 x 6000 ws, and the periphery of the slab is supported by beams or walls of the building frame.

The dynamic vibration absorber used in the experiment has a mass Md = 49 kg4
On the stand, the mass Md was supported by a vibration-proof rubber stand consisting of elements of a spring constant Kd and a resistance Rd, each of which was installed approximately in the vicinity of the center of the slab. Since the targeted resonant natural frequency fs is approximately 70Hz, the anti-resonant natural frequency f
d was also adjusted to about 70 Hz.

In the figure, (a) shows the impedance at the center of the slab at both the excitation point and the receiving point (driving point impedance), and (b)
is the measurement result of impedance (transfer impedance) where the excitation point is at the center of the long side of the periphery of the slab (on the beam) and the receiving point is at the center of the slab.

As can be seen in the figure, due to the installation of dynamic vibration absorbers, both
The impedance valley around Hz has disappeared, which means that when an impact excitation force is applied to the slab, the floor impact noise in this region is reduced = [Effects of the Invention] The present invention By simply installing a dynamic vibration absorber under the upper floor with a space between the slabs, vibrations related to the slab can be controlled and floor impact noise can be reduced. Furthermore, since the dynamic vibration absorber is installed in the underfloor space, it does not become a nuisance or get in the way.

The present invention can control not only floor impact noise but also slab vibration caused by external vibration other than the floor impact excitation force transmitted to the slab, so the external vibration has an adverse effect on occupants above and below, precision machinery, etc. It is possible to reduce vibrations and radiated sound.

According to the present invention, the increase in weight given to the slab is mostly only the added load of the dynamic vibration absorber, so it is slight, and unlike conventional slab vibration control methods, no load is placed on the frame structure, and Since it directly and effectively acts on the natural frequency of , it is simple, low-order, and high-performance.

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

[Brief explanation of the drawing]

FIG. 1 is a detailed explanation of the present invention, in which (a) is a partially cutaway plan view, (bl is a sectional view taken along line A-A' in (a), and FIG. 2 is a cross-sectional view of the present invention). Experimental results showing basic effects,
(a) is a graph of the driving impedance of the specimen slab;
False) is also a graph of transfer impedance. l-・-------slab, 2-・----beam or wall,
3... Floorboards of the upper floor, 4a--joists (for between fulcrums), 4b--one joist (for connection), 5-
・−・−Vibration-proof rubber stand, 6・・−−−−Space under one floor, 7
-...-Additional load, 8-1111...Spring stand, 9-...-
Shock excitation force, 10-... Radiated sound.

Claims (1)

[Claims] (1) An upper floor is provided with a space above the floor slab of the building frame, and is supported at the periphery of the floor slab or at the vibration mode nodes of the floor slab, and And near the antinode position of the vibration mode of the floor slab,
A soundproof floor characterized by installing a dynamic vibration absorber consisting of a combination of an added load, a spring, and a resistance adjusted to match the natural frequency of the floor.