JPH0444503A - Steel expansion joint - Google Patents

Abstract

PURPOSE:To prevent a sealing material from swelling and falling-off and, at the same time, to simplify manufacture and to promote durability by bending coil springs while deforming a steel expansion joint itself in the case an interval between web plates is reduced. CONSTITUTION:Web plates 2 are borne vertically on bridge girders 7 and 7 opposite to each other by keeping an interval S, and face plates 3 keeps an interval 6 each other to fix them to the upper ends of the web plates 2 horizontally. An appropriate number of coil springs 4 are constructed between the web plates 2 downward of the face plates 3, and bearing plate 5 is mounted on the coil springs 4. The tension of the coil springs 4 is so set that it is weakened to the extent that swelling upward of an elastic sealing material 1 is not generated and that it is strengthened to the extent that buckling downward thereof can be prevented in the case the interval S is reduced. In addition, when the interval S is increased, it is strongly set to the extent that the settlement by dead weight of the sealing material 1 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steel expansion joint used in bridges.

[Prior Art] In recent years, non-drainage type steel expansion joints have been mainly used as steel expansion joints for bridges. This is to reduce impact noise when vehicles pass by, and to prevent rainwater from flowing in from the steel expansion joints and corroding the bridge girder support.

In non-drainage type steel expansion joints, the elastic sealant is generally installed so that it is always in a compressed state.

The reason for this is to prevent the sealant from peeling off from the web plate when the sealant is in tension, and also because the weather resistance of the sealant is reduced in the tension state. Therefore, although the sealing material is always in a compressed state, a problem arises in that the sealing material protrudes from the gap between the two face plates due to the internal pressure. In order to reduce the amount of this protrusion toward the upper surface (road surface), a free space is provided under the lower surface of the sealant as shown in FIGS. 2 and 3.

[Problem to be solved by the invention] However, if the wear interval is reduced as it is,
As shown in FIG. 2, buckling of the sealing material may occur. Further, when the wear interval increases, since the sealing material itself is elastic, its own weight may cause the upper surface of the sealing material to sink by a sinking amount δ, as shown in FIG.

However, prevention of buckling and subsidence of the elastic sealing material depends solely on the stability of the elastic sealing material itself or the rigidity of the back-up material, and no active measures have been taken.

Therefore, the conventional method can be applied to bridges with an expansion/contraction movement of about 200 degrees per month, but it cannot be applied to larger-scale bridges, especially bridges with a length of 200 m or more (that is, the amount of expansion/contraction movement is 200 degrees or more). It's impossible.

However, in recent years, it has become mainstream to make bridge girders continuous in order to improve earthquake resistance and running performance, and the ratio of simple girders to continuous girders is currently undergoing a major change. Therefore, the above-mentioned drawbacks in conventional joints are recognized as serious.

The present invention is applied to a non-drainage type steel expansion joint using an elastic sealant, and prevents the sealant filled in the steel expansion joint from protruding or falling off due to expansion and contraction of a bridge, and also improves manufacturing efficiency. The aim is to simplify the structure and improve durability.

[! ! Means for Solving the Problem] A steel expansion joint includes a pair of web plates, a pair of face plates, a coil spring, a support plate, and an elastic sealing material.

The web plate and face plate are made of steel.

Each web plate is placed on a bridge girder that is spaced apart from each other.
Each is supported vertically. Both face plates are separately fixed horizontally to the upper end of the web plate with a gap maintained between them. A coil spring is mounted on the web plate anchorage below the face plate, and the support plate rests on the coil spring. An elastic sealant is filled in the space surrounded by both web plates, both face plates, and the support plate. The tension of the coil spring is set to an extent that can prevent the elastic sealant from protruding and buckling when the distance between the web plates decreases, and to prevent the sealant from sinking due to its own weight when the distance increases. It is assumed that

[Operation] When the distance between the web plates decreases, the internal stress of the elastic sealing material increases. This internal stress concentrates on the side of the coil spring with less resistance, causing the coil spring to bend while deforming itself. This prevents the sealant from protruding onto the upper surface of the face plate, and also prevents downward buckling due to the tension of the coil spring.

Conversely, if the web plate spacing increases, the internal stress in the elastic sealant decreases. The intermediate portion tends to sag due to its own weight, but the greater tension of the coil spring prevents this from sagging, thereby preventing the upper surface of the sealant from sinking.

[Example] In FIG. 1, a steel expansion joint includes a pair of web plates 2, a pair of face plates 3, a coil spring 4, a support plate 5, and an elastic sealing material 1.

The web plate 2 and face plate 3 are made of steel.

Each web plate 2 is connected to a bridge girder 7 that faces each other with a distance S between them.
．． It is supported vertically on 7. The face plate 3 is fixed horizontally to the upper end of the web plate 2 with a gap 6 maintained between them. A suitable number of coil springs 4 are suspended between the web plates 2 below the face plate 3. The support plate 5 is placed on the coil spring 4. The elastic sealing material 1 is filled in the space surrounded by both the web plates 2, both the face plates 3, and the support plate 5.

The support plate 5 functions as a mold when the sealant 1 is injected, and is interposed between the sealant 1 and the coil spring 4 to support the sealant 1 after the injection.

The shape of the support plate 5 is ribbed (Fig. 4) or corrugated (Fig. 5).
) is desirable from the viewpoint of preventing misalignment between the sealing material 1 and the support plate and increasing the support strength.

FIG. 6 shows the state of the joint at the time of manufacture, and the wear clearance is the designed firing clearance. FIG. 7 shows the state in which the joint is in use.

The tension of the coil spring 4 is set as follows.

That is, when the wear interval S decreases, the elastic sealing material 1 is weak enough not to protrude upward, and
Set it to be strong enough to prevent downward buckling. Moreover, it is set to be strong enough to prevent the sealing material 1 from sinking due to its own weight when the distance S increases.

When the web spacing S decreases due to elongation of the bridge, the sealing material l deforms in a direction that causes the coil spring 4 to deflect. This prevents the sealing material 1 from protruding onto the upper surface of the face plate 3, and also prevents buckling as shown in FIG. 2 due to the tension of the coil spring. Conversely, when the wear interval is larger than the normal interval, the tension of the coil spring 4 overcomes the hanging blade due to the weight of the sealing material 1, so that the upper surface of the sealing material 1 can be prevented from sinking.

Additionally, if the end of the bridge has an angle that is not a right angle, the bridge will also move in the longitudinal direction of the joint (in the direction of the arrow in Figure 1), but the coil spring should be able to sufficiently follow this movement. I can do it.

[Effects of the Invention] A feature of the present invention is that a coil spring is used as a back-up material for the elastic sealant, and this spring prevents the sealant from protruding and buckling when the clearance of the steel expansion joint is reduced. Furthermore, it is possible to prevent the top surface from sinking when the expansion joint play increases.

This spring effect is particularly effective when the expansion/contraction fluctuation width is large, and it is fully effective even when the fluctuation width is around 2001, where current various types of non-drainage type tonal joints have a slight lag. I can do it.

[Brief explanation of drawings]

FIG. 1 is a slope view, FIGS. 2 and 3 are front views, FIGS. 4 and 5 are slope views, and FIGS. 6 and 7 are front views. l... Elastic sealing material, 2... Web plate,
3... Face plate, 4... Coil spring, 5...
...Support plate, 6...Gap, 7...Bridge girder, L...Spacing, S...Spacing, δ...Settlement amount. Patent applicant: Japan Road Public Co., Ltd. P-Nis Concrete Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A pair of web plates (2), a pair of face plates (3), a coil spring (4), a support plate (5), and an elastic sealing material (1), the web plate (2) and The face plates (3) are made of steel, and each web plate (2) is vertically supported separately on the bridge girders (7) facing each other with a gap (S) maintained between them, and both face plates (3) are spaced apart from each other. (6) Each is fixed horizontally to the upper end of the web plate (2), keeping the coil spring (4)
is below the face plate (3) and the web plate (
2), the support plate (5) is placed on the coil spring (4), and the elastic sealant (1) is installed between both web plates (2), both face plates (3) and the support plate (5).
The tension of the coil spring (4) is such that the tension of the coil spring (4) is such that it can prevent the elastic sealant (1) from protruding and buckling when the distance (S) decreases, and A steel expansion joint characterized by being set to such an extent that it can prevent the sealing material (1) from sinking due to its own weight when (S) increases.