JPH0489902A - Structure of expansion spacing of road bridge - Google Patents

Abstract

PURPOSE:To make a back-up material adequately follow extension/contraction of an expansion spacing to secure a stable road surface by forming an arc shaped inflated portion in full length on a polyurethane resin formed of a foam body of continuous foam. CONSTITUTION:A back-up material 5 composed of a polyurethane resin foam body is arranged in an expansion space 10 of a road bridge, top of which is filled with an elastic seal material 7 and on top thereof finger plates 9, 9 are arranged. The polyurethane resin is composed of a foam body of continuous foam and arc shaped inflated portion 6 is formed in full length on the surface thereof. A layer of a dustproof material 8 composed of a continuous foam body is also formed between the elastic seal material 7 and the finger plates 9, 9.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a backup material made of polyurethane resin foam that is placed between gaps in a road bridge, filled with an elastic sealing material, and a finger The present invention relates to the structure of a telescopic gap in which plates are arranged.

(Prior art and its problems) This type of expansion joint is already known from Japanese Patent Laid-Open No. 58-160402.

In the above technology, the backup material is constructed in the form of a flat plate with inverted isosceles triangle-shaped through holes extending through it in the longitudinal direction, and when the gap contracts due to thermal expansion of the road base, the backup material bends downward without force. This prevents the elastic sealing material from protruding toward the road surface or buckling within the clearance.

However, since the backup material with this structure absorbs expansion and contraction by utilizing changes in the cross-sectional shape of the cavity, it can be applied to small expansion and contraction widths of about 5 to 150 cm, but it can be applied to expansion and contraction widths as small as 5 to 150 cm. It is not possible to follow the expansion and contraction of large gaps.

Modern road bridges tend to have fewer gaps in order to reduce vibration and noise when vehicles pass through the gaps.

For this reason, gaps with long girders and expansion/contraction widths of about 400 days are emerging.

Although elastic sealing materials have been developed to accommodate larger gaps, the expansion and contraction properties of the backup materials that can support the elastic sealing materials and absorb volume changes are still insufficient, making it difficult to use the elastic sealing materials when compressing the gaps. There are inconveniences such as protruding upwards and protruding onto the road surface, or protruding downwards and causing buckling.

Further, when the free space is extended, a gap is generated between the finger plate and the elastic sealing material. This gap is understood as a "sag" and is generated due to residual strain in the backup material once it has been compressed. "Down"
If this occurs, pebbles, etc. may enter and accumulate between the finger plate and the elastic sealing material, preventing the smooth expansion and contraction of the gap. (diameter of about 5I111) must be prevented from entering.

(Technical Issue Ii) The present invention provides an elastic gap in which a backup material made of polyurethane resin foam is placed between the gaps of a road bridge, an elastic sealing material is filled thereon, and a finger plate is placed above the backup material. The objective is to provide appropriate followability when the backup material expands and contracts.

(Technical Means) The technical means to solve this technical problem are: (a) A polyurethane resin is made of a foam with continuous cells, and (b) An arcuate bulge is formed on the top surface over the entire length. To form, is .

In this case, in addition to the above-mentioned technical means, it is possible to form a dustproof material layer made of a foam with air bubbles in communication between the elastic sealing material and the finger plate.

(Effect of technical means) Foamed polyurethane resin with continuous cells is a material with extremely high elasticity, and can be given followability when expanding and contracting, and can absorb the volume change of the elastic sealing material when compressed. can.

If the upper surface of this foam is made to protrude in an arc shape over its entire length, even if the space shrinks and the backup material attempts to reduce its volume, the arc-shaped protrusion portion still exists, so the support function of the backup material itself is impaired. This will not cause the elastic seal material to buckle or buckle, and no dents will occur at the boundary between the backup material and the elastic seal material. In this case, it is desirable to use a foamed polyurethane resin with low compressive residual strain.

The foamed dust-proofing material layer absorbs the volume change of the elastic sealing material during free contraction, and serves as an intermediate layer between the finger plate and the elastic sealing material, allowing the finger plate to move smoothly.

Therefore, the backup material can support itself while decreasing its volume, and can also absorb the volume change of the elastic sealing material.
It has extremely good ability to follow expansion and contraction.

Effects of the present invention) As a result of the backup material being able to properly follow the expansion and contraction of the gaps, the elastic sealing material does not bulge or buckle toward the road surface due to deformation of the backup materials when the gaps contract, resulting in a stable road surface. This has the advantage of ensuring that

In addition, proper expansion and contraction of the backup material means that the function of the sealing material can be completely fulfilled, and there is an advantage that waterproofing or water-tightness in the gap can be guaranteed for a long period of time.

Further, when a foamed dustproof material layer is used, it blocks direct sunlight and prevents deterioration of the elastic sealing material by ultraviolet rays, so there is an advantage that the durability of the sealing material can be improved.

(Example) Next, a specific example of the above technical means will be explained.

FIG. 1 shows a longitudinal section of a non-drainage type expansion/contraction device f(1) using a stainless steel gutter (2).

In this example, there is a compressive residual strain IO in the bottom of the trough 2).
A back-up material (5) was formed by filling open-cell polyurethane foam with N or less, hardness of 20 kg or less, and impact resilience of 30% or more. An arc-shaped bulge (6) is formed on the upper surface of the backup material (5), and the central part of the bulge is approximately 15% of the depth of the backup material (5). ing. The thickness of the arcuate bulge (6) is designed taking into consideration the hardness and impact resilience of the polyurethane foam.

Although the backup material (5) is filled with a polybutadiene-based elastic sealing material (7), other rubber-like elastic bodies can also be used as the sealing material.

A foam sheet made of open-cell EPDM is placed between the elastic sealing material (7) and the finger plate (9) as a dustproof material (8).
). This sheet body may be a foamed body of urethane resin, polyethylene, etc. in addition to EPDM.

The foam used as the backup material (5) and the dustproof material (8) is one in which all or part of the cells are communicated. A partially communicated foam is formed by piercing a closed-cell foam with a needle-like object to force the cells to communicate.

When the free space (10) contracts, the bottom of 4+1 (2) bends downward and the entire backup material (5) tries to move downward, but since the top surface is convex, the backup material (5) ) will not be dented.

Therefore, there is no fear that the elastic sealing material that is contracted will buckle.

Figure 2 shows a non-drainage type telescoping device (
11) is a sectional view of the girder <15) (15) On the belly plate (12>(12)) protruding from the end into the play space (10),
A backup material (5), an elastic sealing material (7), and a dustproof material (8) similar to those in the above embodiment are laminated in this order.

In this embodiment, when the free space (10) is contracted, a part of the hack-up material (5) protrudes downward from between the abdominal plates (12), but since the surface is convex, there is no need to back up the material. The top surface of the material (5) will not be dented.

[Brief explanation of the drawing]

The drawings are for explaining a specific example of the above-mentioned technical means, and FIG. 1 is a cross-sectional view of a telescopic device for the play area, and FIG. 2 is a cross-sectional view of a telescopic device in another embodiment.

Claims (2)

[Claims] (1) A back-up material made of polyurethane resin foam is placed in the gap of a road bridge, an elastic sealing material is filled on top of the back-up material, and a finger plate is placed above it. A road bridge expansion and contraction structure made of foam with an arc-shaped bulge extending over its entire length. (2) The structure of the expandable gap according to claim 1, wherein a dustproof material layer made of open-cell foam is formed between the elastic sealing material and the finger plate.