JPS60112930A - Method of building vibration-proof foundation - Google Patents

Abstract

PURPOSE:To reduce an installation cost and shorten a construction period, by a method wherein a polyethylene sheet is laid over upper surfaces of vibration absorbing rubber and a board such as glass wool, and concrete is placed thereon so that the board is not decreased in thickness over that of the vibration absorbing rubber. CONSTITUTION:After vibration absorbing rubber 3 is laterally and longitudinally aligned in a cavity 2 in a slab 1 being a foundation floor and is adhered to the slab 1, a board 4 such as glass wool is laid over. Thereafter, a polyethylene sheet 5 is laid over the upper surfaces of the vibration absorbing sheet 3 and the board 4, forms 6 are framed, and reinforcing bars are arranged. Concrete 7 is placed in a way that the board 4 is not decreased in thickness over that of the vibration absorbing rubber 3, and the concrete is cured. After the concrete 7 is poured, concrete 8 is further placed thereon to cure it integrally with the concrete 7. This, since the concrete 7 is used as a form bottom plate, eliminates a work to install a trestle on the vibration absorbing rubber 3, resulting in the possibility to reduce a construction cost and a construction period.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing foundations for installing equipment, vibration-proof floating floors in broadcasting studios, floating floors to prevent floor impact noise in apartment buildings, and the like.

Conventionally, as a vibration-proof foundation construction method such as the above-mentioned equipment installation foundation, a method is known in which a pedestal is assembled on top of anti-vibration rubber placed on a reinforced concrete slab and concrete is poured. The disadvantage is that it takes a lot of time and effort to adjust the unevenness between the slab and the anti-vibration rubber or between the anti-vibration rubber and the frame.

In addition, as a construction method for floating floors that prevent floor impact noise in apartment buildings, a method is known in which glass wool, rock wool, etc. is laid on a slab as a spring material, and concrete is poured on top of it.Glass wool.

The static spring constant of rock wool and other materials varies widely, making it difficult to design an accurate anti-vibration design.Furthermore, the spring force may be lost due to weakening due to water intrusion, or the alkaline nature of concrete may cause deterioration and reduce durability. There were drawbacks such as:

In the present invention, first, vibration-proof rubber and boards that are thicker, more flexible, and have a smaller static spring constant are laid on the foundation floor, and then a plastic sheet is laid on top of them. The concrete is poured to a thickness that is not thinner than the anti-vibration rubber, and most of the concrete load is supported by the boards for curing.

Next, after the concrete has hardened to the point where it can be used as a frame or the bottom plate of a form for pouring concrete, a vibration-proof foundation can be constructed by pouring concrete on top of it to the required thickness and integrating it. This is how it was done.

An example of constructing the illustrated equipment installation foundation will be described below.

First, 28 anti-vibration rubbers 3 are arranged vertically and horizontally at a predetermined distance from each other in a horizontally oblong rectangular shallow flat depression 2 formed at a predetermined location on a slab l of a reinforced concrete building serving as a foundation floor, and then glued with an appropriate adhesive. After adhering to slab 1, each anti-vibration rubber 3
All other areas are covered with a board 4 made of glass wool, rock wool, foamed plastic, or the like.

Next, a polyethylene sheet 5 is laid on the vibration isolating rubber 3 and the board 4 so as to cover the entire surface thereof, and a formwork 6 for concrete pouring is established along the edge of the depression 2, and reinforcing bars ( (not shown). Then, concrete 7 is cast on the polyethylene sheet 5 to a thickness that does not make the board 4 thinner than the vibration-proof rubber 3 due to its load, and most of the load is supported by the board 4 for curing.

After the concrete 7 is cured by the above-mentioned curing so that it can be used as a frame or a bottom plate of a form for pouring concrete, concrete 8 is further poured on top of it to a required thickness to be integrated with the concrete 7. This will establish the foundation for installing the equipment.

Now, regarding the virtual unit area 150 c + n x 45 cm,
Let's calculate the load and deflection of the anti-vibration rubber and board. Within this virtual unit area, there is a thickness of 3 cm and a length and width of 12.6 cm.
cm x 12,6CI11. Static spring constant KR=4
One anti-vibration rubber with a weight of 370 kg/cm is placed, and the remaining parts have a weight of 48 kg/n? Assume that glass wool boards with a thickness of 5 cm and a static spring constant KG = 417 kg/cm are laid, and the thickness of the polyethylene sheet 5 laid on top of these is 0.15 mm.

In addition, when the first concrete 7 is poured to a thickness of 10 cm, the weight of the concrete in the above virtual unit area is 155
．． Assume that the weight is 25 kg. The load WG on the board 4 at this time is wG=155.25x ((45x150-12.6x
12.6) ÷ (45X150 ) ) #151.6
kg The static deflection δ,G of board 4 at this time is δG
= 151.6 ÷ 417 = 0.36 The load -R of the CI11 anti-vibration rubber 3 is: WR = 155, -151.6 = 3.4 kg The static deflection δR of the anti-vibration rubber 3 at that time is δR = 3.4 +4
370=0.00078 am.

Therefore, the thickness of the anti-vibration rubber 3 remains almost the same as the concrete 7 is poured, and the thickness of the board 4 becomes approximately 4.6 am, which is still thicker than the anti-vibration rubber 3.

Next, when the second concrete 8 is cast to a thickness of 80 cm, the weight of the concrete of virtual unit area with a thickness of 80 cm is 1242 kg. At this time, the static spring constant K of the anti-vibration rubber 3 and the board 4 is K = KR0KG
=4370+417 =4787kg/cm The deflection δ of both at this time is δ=1242÷4787=0.26cm.

'The total deflection amount δTG of board 4 is δTG=0.3
6+0.26=0.62cm The load WT'G on board 4 at that time is WTG = 417 Xo, 62=25
It weighs 8.5 kg.

Further, the total amount of deflection δTR of the vibration isolating rubber 3 is δTR=0.
26+0.00078 #0.26cm At that time, the load WTR borne by the vibration isolating rubber 3 is WTR=4370X0.2
6=1136.2 kg.

Therefore, the share ratio of the vibration isolating rubber 3 to the total load is 1136.2÷ (1136,2+258.5 > −
Approximately 81% at 0,815, also board 4 for the total load
The sharing ratio is 258.5÷(1136,2+258.5) =0.
185 is about 19%.

According to this sharing ratio, since the influence of the board 4, which has a large variation in spring constant, is slight, a vibration damping effect can be expected due to an accurate vibration damping design based on the vibration isolating rubber 3 having a stable spring constant.

Furthermore, when the concrete 7 is placed for the first time, the board 4 becomes thinner than the vibration isolating rubber 3 due to the load of the concrete 1 and 7, and the concrete 7 covers the vibration isolating rubber 3. The upper end of the swinging rubber 3 is made of concrete 7
If it sinks into the board, the vibration-proofing effect will be significantly reduced, so the first concrete 7 is cast as thinly as possible so that the board 4 does not become thinner than the vibration-proof rubber 3.
Ultimately, it is desirable to increase the share ratio of the vibration isolating rubber to the total load.

Furthermore, as mentioned above, since the share ratio of the vibration isolating rubber 3 to the total load is extremely large, even if the board 4 collapses due to water intrusion after construction, the decrease in the vibration isolating effect is so small that it can be almost ignored.

In addition, in the above example, a case was explained in which the anti-vibration rubber was bonded to the slab first and the boards were laid on the other parts, but the invention is not limited to this. Alternatively, the area to be placed may be cut out, and a vibration-proof rubber may be fitted there and adhered to the slab.

As is clear from the above description, according to the present invention,
A plastic sheet is laid on top of the anti-vibration rubber and board, concrete is poured on top of it, and after curing, this concrete is used as a pedestal or formwork bottom plate.
Since there is no need to assemble the pedestal on the anti-vibration rubber as in the past, it is possible to reduce construction costs and shorten the construction period.

In addition, the board is thicker than the anti-vibration rubber, and the first concrete is cast and cured so that the board does not become thinner than the anti-vibration rubber due to the load, and then concrete is poured on top of the hardened concrete. is cast to the required thickness, and most of the total load of the concrete is borne by the vibration isolating rubber, so the influence of boards with widely varying spring constants is minimal, and the concrete is based on vibration isolating rubber with a stable spring constant. It is possible to construct a vibration-proof foundation with a vibration-proofing effect through accurate vibration-proofing design.

[Brief explanation of the drawing]

The drawings show an example in which the construction method of the present invention is applied to the construction of a foundation for installing equipment. Fig. 1 is a plan view showing the state in which anti-vibration rubber is placed in a depression formed in a slab, and Fig. 2 is a plan view showing the state in which anti-vibration rubber is placed in the depression formed in the slab. A vertical cross-sectional view of the main part showing the state in which the vibration-proof rubber and boards are spread, and Figure 3 shows the state in which a polyethylene sheet is laid on the vibration-proof rubber and boards, and the first concrete is poured on top of it. Fig. 4 is a longitudinal sectional view of the main part showing the
A vertical sectional view of the main part showing the state in which the second concrete is poured on top of the first concrete, and Figure 5-6 is a vertical sectional view and a plan view of the equipment installation foundation constructed by the method of the present invention. . 1... Foundation floor slab, 3... Anti-vibration rubber, 4...
・Board, 5...Polyethylene sheet, 7.8...
concrete. 7 illustrations/v2 illustrations 3 strokes

Claims (1)

[Claims] 1. Place multiple pieces of anti-vibration rubber at predetermined locations on the foundation floor at a predetermined distance from each other. The process of laying boards with a small spring constant, and laying a plastic sheet on top of the vibration-proof rubber and board, and pouring concrete on top of this to a thickness that does not make the board thinner than the vibration-proof rubber due to the load. A vibration-proof foundation construction method comprising the steps of: curing the concrete; and pouring concrete to a desired thickness on top of the curing concrete.