JP2013221292A - Sealant between bridge girder and slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealant which hardly causes lateral falling and positional displacement even when a force is added to the sealant in the lateral direction during positioning of a slab performed when mounting the slab on the sealant on the top surface of a bridge girder.SOLUTION: A sealant 10, which is installed between a bridge girder and a slab arranged above the bridge girder and along the lengthwise direction of the bridge girder, is formed in two layers of an upper foam 11 and a lower foam 21. The upper foam 11 has a skin layer on the outer surface thereof and has a quadrangular cross-sectional shape whose corners are rounded or a circular cross-sectional shape, and the lower foam 21 has a quadrangular cross-sectional shape. The 25% compression hardness of the upper foam 11 is made smaller than that of the lower foam 21.

Description

  The present invention relates to a seal member disposed along a length direction of a bridge girder between a bridge girder and a floor slab in a bridge or a viaduct.

  Conventionally, as shown in FIG. 4, bridge girders 51 made of H-shaped steel are arranged at a necessary interval in the width direction W and above the bridge piers 53 along the bridge axis direction L, and the upper surface of the bridge girder 51 has a width direction W Seal members 55, 55 separated from each other as necessary are juxtaposed along the length direction of the bridge girder 51 (same as the bridge axis direction L), and then a prestressed concrete slab (hereinafter also referred to as a floor slab) is placed on the seal member 55. A method of fixing the floor slab 57 on the bridge girder 51 by placing 57 and placing concrete or mortar 59 between the sealing materials 55 and 55 on the upper surface of the bridge girder 51 is frequently used.

The sealing material 55 acts as a frame between the floor slab 57 and the bridge slab 51 and as a support member for the floor slab 57, and the concrete or mortar remains until the concrete or mortar is cured between the bridge girder 51 and the floor slab 57. The function of sealing so that it does not dew (does not drip) is required. As the sealing material 55, conventionally, a closed-cell foam made of closed-cell polyethylene foam, rubber sponge, or the like formed into a long shape having a square cross section is used.
Also, the sealing material has a two-layer structure of foam, the foam on one side is a closed-cell foam, and the foam on the other side is a foam containing more open cells than the foam on the one side. Has been proposed.

  However, in order to support the floor slab, it is necessary to place concrete or mortar between the bridge girder and the floor slab in a width (area) that can withstand the load of the floor slab. Is required to be narrow, that is, a vertically long shape having a height compared to the width. In such a shape, when a horizontal force is applied by rubbing on the lower surface of the floor slab when finely adjusting the position of the floor slab, which is performed when the floor slab is lifted with a crane and placed on the sealant on the bridge girder , May fall sideways or slip sideways. In that case, after the floor slab is separated above the sealing material and the sealing material is corrected to the correct position, the position of the floor slab must be adjusted again.

JP 2003-155708 A JP 2003-155709 A

  The present invention has been made in view of the above points, and is difficult to cause lateral displacement or misalignment when the position of the floor slab is adjusted when the floor slab is placed on the sealing material. The purpose is to provide.

  The invention according to claim 1 is a sealing material disposed along the length direction of the bridge girder between the bridge girder and the floor slab disposed above the bridge girder, wherein the upper foam and the lower foam are laminated. The upper foam has a square or round cross-sectional shape with rounded corners, the lower foam has a square cross-sectional shape, and has a 25% compression hardness of the upper foam. The sealant between the bridge girder and the floor slab is characterized by being smaller than the 25% compression hardness of the lower foam.

  According to a second aspect of the present invention, in the first aspect, the upper foam has a skin layer on a surface exposed to the outside.

  In the sealing material of the present invention, since the hardness of the upper foam is lower than that of the lower foam, when the position of the floor slab is adjusted, the upper surface of the upper foam is rubbed with the lower surface of the floor slab, etc. When a lateral force is applied to the sealing material, the upper foam having a low hardness is mainly deformed, and the deformation can be suppressed for the lower foam having a high hardness. Moreover, since the upper foam has a quadrangular or circular cross-sectional shape with rounded corners, the bonding width with the lower foam of the upper foam is smaller than the maximum cross-sectional width of the upper foam, and the lateral foam When the force is applied and the rotation is deformed, the rounded corners of the bottom are less likely to interfere with each other, so that the upper surface of the lower foam is easily deformed in the lateral direction. Therefore, the sealing material of the present invention can absorb the force by deformation of the upper foam and suppress the deformation of the lower foam when a lateral force is applied during the position adjustment of the floor slab. Therefore, it is possible to prevent the entire sealing material from falling down or shifting its position, eliminating the need for troublesome work such as reattaching the sealing material, and simplifying the construction work. In addition, the upper foam has a square or round cross-sectional shape with rounded corners, so even if the floor slab lower surface is inclined or has an uneven surface, it is possible to secure a ground contact area with the floor slab lower surface and improve sealing performance. it can.

  Further, since the sealing material of the present invention has a skin layer on the surface where the upper foam is exposed to the outside, the upper foam may be rubbed on the lower surface of the floor slab when the position of the floor slab is adjusted. However, there is an effect that the surface is hardly damaged and the sealing property is not easily impaired.

It is a perspective view of the sealing material which concerns on embodiment of this invention. It is an expanded sectional view which shows the upper surface vicinity of the upper side foam in the sealing material of FIG. It is sectional drawing which shows the effect | action of the sealing material of FIG. It is a schematic perspective view which shows a bridge girder, a sealing material, a floor slab, etc.

  Hereinafter, embodiments of the present invention will be described. The sealing material 10 shown in FIG. 1 is arranged along the length direction of the bridge girder 51 between the bridge girder 51 shown in FIG. 4 and the prestressed concrete floor slab 57 arranged above the bridge girder 51. The required dimensions are set according to the construction conditions. In use, the required number is connected in the length direction of the bridge girder according to the length of the bridge girder.

The sealing material 10 is a long product in which the upper foam 11 and the lower foam 21 are laminated and integrated with an adhesive, a double-sided adhesive tape, or the like.
The upper foam 11 is a rod-shaped body having a quadrangular shape with rounded corners 15 or a circular cross-sectional shape. As the material of the upper foam 11, a foam having elasticity such as polyurethane foam is suitable. The upper foam 11 preferably has a skin layer 12 on the outer surface as shown in the enlarged sectional view of FIG. The skin layer 12 is a dense film formed by compressing bubbles or by reducing the bubble size, and has high smoothness and is not easily torn. The position adjustment of the floor slab 57 that sometimes rubs the upper surface of the upper foam 11 is facilitated, and even if the floor slab 57 is rubbed, it is difficult to break. Furthermore, since the water permeability is low, the sealing performance for preventing moisture leakage of the concrete and mortar is also improved.

In addition, as a manufacturing method of the foam having a skin layer on the surface, the method described in Japanese Patent No. 3987252, that is, on the upper smooth surface of the formed paper (release paper) that is continuously fed from the cardboard roll and travels. There are a method in which a urethane raw material is continuously supplied and both ends of the molding paper are put into a square tube shape and foamed, or a molding method in which a urethane raw material is foamed in a molding die. The foam molded by the former method is preferable because it can be a long product having only one parting line (PL). On the PL, the skin layer may be cut or protruded more than the surroundings to lower the sealing performance. Therefore, the upper foam PL molded by this method is brought into contact with the lower foam, It is preferable to join so as to be sandwiched between the foam and the lower foam. By molding in this way, a sealing material having a skin layer on the entire exposed surface of the upper foam that may be in contact with the floor slab can be obtained.
Further, if the cross-section of the upper foam 11 is a quadrangle with rounded corners 15, the joining surface becomes smooth when joining on the lower foam, so that stable joining is easy. As mentioned above, the surface of the upper foam made of a long product with only one PL is joined to the upper surface of the lower foam with a double-sided adhesive tape, adhesive, etc. The upper foam 11 and the lower foam 21 can be integrated by sandwiching PL inside the sealing material 10.

The upper foam 11 preferably has a density (JIS K7222: 2005) of 90 to 170 kg / m ³ and a 25% compression hardness (JIS K6400-2: 2004 D method) of 5 to 25 kPa. When the density is lower than the above range, the water-stopping property is insufficient. On the other hand, when the density is high, it becomes hard and the handling property is deteriorated. Further, when the 25% compression hardness is lower than the above range, the water stoppage is insufficient, while when it is high, the compressive residual strain increases.

  The lateral foam w1 of the upper foam 11 is preferably 10 to 100 mm, and the height h1 is preferably 10 to 100 mm. Furthermore, the ratio of the width w1: height h1 is preferably 1: 0.5-2. When the height h1 is smaller than the above range, it becomes difficult to absorb the dimensional variation of the PC floor slab and the steel plate. On the other hand, when the height h1 is larger, the seal material falls down greatly when the floor slab is installed and deviates from the planned installation position. There is a fear.

The lower foam 21 is made of a rod-like body having a square (square or rectangular) cross-sectional shape with corners (that is, the four corners are not rounded). Examples of the material of the lower foam 21 include polyurethane foam, rubber sponge, polyolefin foam, and the like. Particularly preferred are polyolefin foams such as polyethylene foam.
The lower foam 21 preferably has a density (JIS K7222: 2005) of 20 to 200 kg / m ³ and a 25% compression hardness (JIS K6400-2: 2004 D method) of 30 to 350 kPa. When the density is lower than the above range, the water-stopping property is insufficient. On the other hand, when the density is high, it becomes hard and the handling property is deteriorated. Further, even when the 25% compression hardness is lower than the above range, the water stoppage is insufficient, and at the same time, the deformation in the lateral direction is increased.

  The 25% compression hardness of the lower foam 21 is greater than the 25% compression hardness of the upper foam 11. That is, the 25% compression hardness of the upper foam 11 is smaller than the 25% compression hardness of the lower foam 21. Furthermore, the 25% compression hardness ratio between the upper foam 11 and the lower foam 21 is preferably in the range of 1: 1.5 to 1:70. When the 25% compression hardness of the lower foam 21 is smaller than the range of the 25% compression hardness ratio, the lower foam 21 is more preferable than the relative hardness preferred for the upper foam 11. Becomes a low hardness. For this reason, when a floor slab is adjusted when the floor slab is placed on the seal material 10, when a lateral force is applied to the seal material 10 due to the floor slab coming into contact with the seal material 10 or the like. It becomes easy to deform | transform on the said lower side foam 21 side, and the whole sealing material 10 becomes easy to fall down from a bottom part. On the other hand, when the 25% compression hardness of the lower foam 21 is larger than the range of the 25% compression hardness ratio, the lower foam 21 is preferable relative to the upper foam 11. Therefore, when the floor slab is placed, the deformation adhesiveness of the lower foam 21 is impaired, and the sealing performance is lowered.

  The lower foam 21 preferably has a lateral width w2 of 10 to 100 mm and a height h2 of 10 to 100 mm. Furthermore, the ratio of the width w2: height h2 is preferably 1: 0.5-2. When the height h2 is smaller than the above range, the sealing material 10 is stable, but the amount of concrete and mortar filled between the sealing materials 10 is insufficient, and the support capacity of the floor slab may be insufficient. . On the other hand, when it becomes larger, the height of the lower foam 21 is too high, and there is a possibility that the whole sealing material 10 may fall from the bottom when the floor slab is installed.

  Furthermore, the ratio of the height h1 of the upper foam 11 to the height h2 of the lower foam is preferably 1: 0.5-2. When the height h2 of the lower foam 21 is smaller than the range of the height ratio, the height of the upper foam 11 is too high, and the sealing material is greatly collapsed when the floor slab is installed. There is a risk of deviation from the planned position. On the other hand, when it becomes large, there is a possibility that the sealability is deteriorated due to insufficient compression margin to cope with variations in dimensions of the PC floor slab and the steel plate.

Moreover, although the height (h1 + h2) of the said sealing material 10 is set according to the space | interval between a floor slab and a bridge girder, it is usually set to 40 mm-150 mm. The height (h1 + h2) of the sealing material 10 is equal to or larger than the larger dimension (the maximum lateral width Wu of the sealing material 10) of the lateral width w1 of the upper foam 11 and the lateral width w2 of the lower foam 21; It is preferable that (h1 + h2): Wu = 1: 0.2-1. If the maximum width Wu of the sealing material is smaller than the above range, the entire sealing material 10 may fall from the bottom when the floor slab is installed. If the maximum width Wu of the sealing material 10 is larger than the above range, the amount of concrete and mortar filled between the sealing materials 10 may be reduced, and the support capacity of the floor slab may be reduced.

  The sealing material 10 is a bottom surface (bottom surface) of the lower foam 21 as shown in (3-A) and (3-B) of FIG. 3 at the time of floor slab construction (including bridge girder repair work). It is fixed to both edges in the width direction of the upper surface of the bridge girder 51 by an adhesive member 31 made of a double-sided pressure-sensitive adhesive tape, an adhesive or the like. Then, the floor slab 57 as shown in FIG. 4 is lifted by a crane and placed on the sealing material 10 while adjusting the position on the bridge girder 51. At that time, when a lateral force F is applied to the sealing material 10 by rubbing the upper surface of the sealing material 10, that is, the upper surface of the upper foam 11 with the lower surface of the floor slab, the hardness of the upper foam 11 And the hardness of the lower foam 21 are in the above relationship, the upper foam 11 having a relatively low hardness is mainly deformed, and the lower foam 21 having a relatively high hardness is deformed. Can be suppressed. Further, the skin layer 12 formed on the outer surface of the upper foam 11 improves slippage on the upper surface of the upper foam 11 and may be performed while contacting the upper surface of the upper foam 11. Not only is the position adjustment easy, but even if the upper surface of the upper foam 11 is rubbed with a floor slab, the upper foam 11 is difficult to break.

  Further, the upper foam 11 has a quadrangular or circular cross-sectional shape with rounded corners 15, and the width (Ws) at the contact surface with the lower foam 21 of the upper foam 11 is the cross section of the upper foam 11. Therefore, the round corners 15a and 15b at the bottom of the bottom foam 21 do not interfere with the lateral force F during deformation and are easily deformed in the lateral direction on the upper surface of the lower foam 21. In addition, since the lower foam body 21 has a square cross-sectional shape with corners, the lower foam body 21 can be stretched at the corners 25a and 25b at the bottom against a lateral force, and is difficult to roll. Therefore, the sealing material 10 is deformed in the lateral direction mainly in the portion of the upper foam 11 with respect to the lateral force, and the whole sealing material 10 falls from the bottom or shifts in position. Can be prevented. Therefore, troublesome work such as re-sticking work of the sealing material is not required, and the construction work can be simplified.

Moreover, since both the said upper foam 11 and the lower foam 21 consist of a foam, the said sealing material 10 is lightweight, and the handling at the time of construction is easy. Further, the lower foam 21 can be prepared by cutting a foam sheet material into a square cross section, and the height can be freely changed by simply changing the cut dimensions. It is possible to quickly form and cope with a seal material having a height different from the planned setting, or when an emergency with a limited construction period is required.
In addition, after mounting the floor slab on the sealing material 10, concrete or mortar is filled between the sealing materials 10, and the bridge girder and the floor slab are integrated and supported.

DESCRIPTION OF SYMBOLS 10 Sealing material 11 Upper foam 12 Skin layer 15 Round corner 15a, 15b Round corner 21 Bottom foam

Claims (2)

A sealing material disposed along the length direction of the bridge girder between the bridge girder and the floor slab disposed above the bridge girder,
It consists of two layers in which the upper foam and the lower foam are laminated and integrated,
The upper foam has a square or round cross-sectional shape with rounded corners,
The lower foam has a square cross-sectional shape,
A sealing material between a bridge girder and a floor slab characterized in that a 25% compression hardness of the upper foam is smaller than a 25% compression hardness of the lower foam. The sealing material between a bridge girder and a floor slab according to claim 1, wherein the upper foam has a skin layer on a surface exposed to the outside.

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