GB2218437A

GB2218437A - Expansion joint for roads and bridges

Info

Publication number: GB2218437A
Application number: GB8900173A
Authority: GB
Inventors: Naotake Ando; Taizo Matsukami; Hiroshi Saito
Original assignee: Sho Bond Corp
Current assignee: Sho Bond Corp
Priority date: 1988-03-17
Filing date: 1989-01-05
Publication date: 1989-11-15
Anticipated expiration: 2009-01-05
Also published as: GB2218437B; MY103397A; GB8900173D0; JPH01167406U; AU2684988A; AU594595B2

Abstract

A cover member 3 spans an expansion joint gap 6 defined between two adjacent spaced apart sections of a surface layer 2 overlaid upon a support layer 1 of a road or bridge. A highly deformable elastomeric layer 4 is overlaid upon the support layer 1 and the cover member 3. A visco-elastic composite material layer 5 composed of aggregates and binders fills the expansion joint gap so as to be flush with the upper surface of the surface layer 2. <IMAGE>

Description

EXPANSION JOINT FOR ROADS AND BRIDGES The present invention relates to an expansion joint for roads and bridges such as elevated roads and bridges spanning rivers, valleys and the like, and more particularly to a seamless expansion joint for use in joining two adjacent spaced apart sections of roads and bridges.

As is typified by a finger joint, in a conventional expansion joint, in order to permit two adjacent spaced apart sections of a road or bridge to move horizontally towards and away from each other, an open gap is provided between the two sections and is generally spanned by a sealingrubber member which is not flush with the upper surface of the road or bridge and therefore forms a rough surface which produces a rough ride for vehicles travelling along the road or bridge. In addition, considerable noise is produced when a vehicle passes over such a rough upper surface of the road or bridge. These are problems inherent in the conventional expansion joint.

In recent years, in order. to resolve the above problems, there has been provided a conventional seamless expansion joint, for example such as is disclosed in Japanese Laid-Open Patent No. 61-191703. The joint is characterized in that an.expansion joint gap formed between two adjacent spaced apart sections of a surface layer of a road or bridge contains a horizontally disposed cover member; and the thus installed cover member is overlaid with a visco-elastic composite material layer composed of binders and aggregates. The top surface of the visco-elastic composite material layer is flush with the upper surface of the surface layer.

The seamless expansion joint provides a smooth ride for vehicles.

In addition, since there is no gap in the seamless expansion joint, noise is substantially absent when vehicles pass over the seamless expansion joint.

However, the conventional seamless expansion joint suffers from its limited amount of expansion. Because the visco-elastic composite material layer is adhesively secured to the two adjacent spaced apart sections of the surface layer overlaid upon a support layer of the road or bridge and is also secured to the upper surface of the support layer, local concentrations of stresses occur between the support layer and the viscoelastic composite material layer. This limits the amount of expansion and makes it impossible for the visco-elastic composite material layer to expand in response to movement of the support layer. As a result of such local concentrations of stresses, cracks are produced in the visco-elastic composite material layer.

On the other hand, a visco-elastic composite material layer with a sufficient amount of expansion would be of low rigidity and this would make it difficult to provide a top surface of the composite material layer flush with the upper surface of the surface layer. These are problems inherent in the conventional seamless expansion joint.

It is an aim of the present invention to overcome or greatly mitigate the above problems inherent in the conventional expansion joints by providing an expansion joint sufficiently expandable in response to the expansion of a support layer of the road or bridge.

According to the present invention, there is provided an expansion joint for a road or a bridge, comprising a cover member positioned in an expansion joint gap defined between two adjacent spaced apart sections of a surface layer overlaid upon a support layer; a visco-elastic composite material layer in the expansion joint gap above the cover member, the top surface of the composite material layer being flush with the upper surface of the surface layer; and a deformable elastomeric layer positioned on top of the support layer and the cover member and beneath the visco-elastic composite material layer.

The elastomeric layer is preferably made of polybutadiene rubber or silicone rubber.

Because the visco-elastic composite material layer filling the expansion joint gap is insulated from the support layer of the road or bridge through a deformable elastomeric layer, it is possible to permit the composite material layer to deform on the upper surface of the support layer of the road or bridge. In addition, since the visco-elastic composite material layer is secured only to the two adjacent spaced apart sections of the surface layer overlaid upon the support layer, it is possible to permit the two sections of the surface layer to move in response to movement of the support layer, whereby expansion is absorbed by the seamless expansion joint of the present invention.

The invention will now be described by way of non-limiting example with reference to the accompanying drawing, labelled Fig. 1, which is a longitudinal sectional view of an expansion joint in accordance with the present invention.

In Fig. 1, the reference numeral 1 denotes a support layer; 2 a surface layer; 3 a cover member; 4 a highly deformable elastomeric layer; and 5 a visco-elastic composite material layer.

An expansion joint gap 6 is formed between two adjacent spaced apart sections of the surface layer 2 overlaid upon respective adjacent spaced apart sections of the support layer 1 of the road or bridge. If necessary, joint-sealing material 7 is placed in the expansion joint gap 6 as shown in Fig. 1.

The cover member 3 comprises, for example, an aluminum plate or the like. By means of the cover member 3 spanning the expansion joint gap 6 above the two adjacent spaced apart sections of the support layer 1, the visco-elastic composite material layer 5 and the elastomeric layer 4 are prevented from dropping into the part of the expansion joint gap 6 between the two sections of the support layer 1.

The elastomeric layer 4 is made of polymers such as polybutadiene rubber and silicone rubber of high deformability so as to have an expansion rate of, for example, about 200%. The material of the elastomeric layer 4 is poured into the expansion joint gap 6 on top of the cover member 3 so as to form a continuous elastomeric layer 4 having a thickness of from about 2 to about 5mm on the cover member 3. In this embodiment of the present invention, the elastomeric layer 4 is made of polybutadiene rubber since polybutadiene rubber is highly deformable and of low temperature sensitivity, whilst being good at adhering to concrete slabs, stone materials, metallic materials and the like.In addition, polybutadiene rubber is of excellent durability and has good heat-resisting properties so as not to produce any foam even when brought into contact with heated aggregates or binders.

On the other hand, the visco-elastic composite material layer 5 is composed of a composite material prepared from suitable aggregates such as ceramic materials and the like mixed with a binder which is a composite material or mixture of a rubber-elastomeric material and a liquid-binder material.

Any of the aggregates and a primer 8 coating the faces of the sections of the surface layer facing into the expansion gap may be made of conventional materials and installed in a conventional manner.

The expansion joint for the road or bridge-can be installed as follows: First, the surface layer 2 overlaid upon the support layer 1 of the road or bridge is removed in the expansion joint area to expose the two adjacent spaced apart sections of the support layer 1. Between the sections of the surface and support layers is formed the expansion joint gap 6 in which is installed the joint-sealing material 7 covered by the cover member 3 spanning the expansion joint gap. The primer 8 is applied to each of the faces of the two adjacent spaced apart sections of the surface layer. After that, the elastomeric material of the elastomeric layer 4 is poured into the expansion joint gap 6 on top of the cover member 3 and top surfaces of the two sections of the support layer 1.

Then, cleaned aggregates are placed in the expansion joint gap 6 on top of the thus poured elastomeric layer 4, and the binder is added to the aggregates to form the visco-elastic composite material layer 5, the top surface of which is pressed and finished by means of roller means so as to be flush with the upper surface of the surface layer 2.

In the seamless expansion joint: (1) The highly deformable elastomeric layer 4, which is interposed between the visco-elastic composite layer 5 and the support layer 1, makes possible expansion of the support layer; (2) Since the visco-elastic composite material layer 5 is insulated from the support layer 1 by the elastomeric layer 4 while being adhesively secured to the two adjacent spaced apart sections of the surface layer 2 overlaid upon the support layer 1, expansion of the support layer 1 is absorbed by the full width of the visco-elastic composite material layer 5 between the coatings of primer 8.

Since the visco-elastic composite material layer 5 is insulated from the support layer 1 by the highly deformable elastomeric layer 4, local concentrations of stresses are prevented from occuring in the expansion joint so that the surface layer 2 is prevented from cracking; and (4) Since the expansion joint of the present invention is a seamless type joint, it is possible to provide a smooth ride for vehicles travelling thereoii a and to reduce the level of noise produced by vehicles travelling thereon.

Claims

1. An expansion joint for a road or bridge, comprising a cover member positioned in an expansion joint gap defined between two adjacent spaced apart sections of a surface layer overlaid upon a support layer; a visco-elastic composite material layer in the expansion joint gap above the cover member, the top surface of the composite material layer being flush with the upper surface of the surface layer; and a deformable elastomeric layer positioned on top of the support layer and the cover member and beneath the visco-elastic composite material layer.

2. An expansion joint according to claim 1, wherein the elastomeric layer is made of polybutadiene rubber.

3. An expansion joint according to claim 1, wherein the elastomeric layer is made of silicone rubber.

4. An expansion joint for a road or bridge, substantially as herein described with reference to the accompanying drawing.

5. Each and every novel feature and combination of features as herein disclosed and/or illustrated.