JPH0641917A - Continuous synthetic floor board bridge - Google Patents

Abstract

PURPOSE:To prevent crack of a floor board by passing a cable installed in such a manner as to go through an upper concrete area of a support like a convex surface and go between supports like a concave surface through a holder in its elongated state through a continuous synthetic floor board bridge and fixing the same. CONSTITUTION:A concrete 1 comprising a concrete filling part 10, a foam styrol 3 and a floor system concrete 11 is provided on a continuous steel cross beam 12 supported on fixed supports 4 and movable supports 5 on a bridge pier. A cable 8 is inserted through plural cable sheaths 6 provided on a floor board concrete 11, and disposed like a wave by fixing the cable with plural cable holders 7 provided on the steel cross beam 12 between the supports 4, 5. Further, tensile force is applied to both ends of the cable 8 by a cable tensing device 9 to elongate the cable 8, and both ends of the cable are fixed to both ends of the concrete 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous synthetic slab bridge in which synthetic slab bridges are continuous in the longitudinal direction thereof.

[0002]

2. Description of the Related Art In highways in urban areas, viaducts are often used across multiple spans in order to effectively use land and alleviate traffic congestion. As one of the forms of this viaduct, a multi-span simply supported composite slab bridge in which the synthetic slab bridges supported by each span and provided with concrete slabs on the upper surface of steel girders are arranged in the longitudinal direction. There is. As one of the simply supported synthetic slab bridges, Japanese Patent Publication No. 3-48285 discloses a hollow synthetic slab bridge. This hollow type composite slab bridge is widely used for bridge replacement and the like because it has an excellent function that its girder height is low and applicable spans are wide. However, in the connection part of the above-mentioned simple support synthetic floor slab,
An expansion joint having a slight gap is provided to cope with expansion and contraction due to temperature change of the synthetic slab bridge and rotation of its end. Since the expansion joint is directly loaded with a wheel load, vibrations are generated by a vehicle traveling on a simply supported composite floor slab bridge, particularly a vehicle traveling at a high speed on a highway, which results in noise. For this reason, continuous viaduct bridges that do not require expansion joints at their connecting parts are often used for viaducts that span multiple diameters of highways.

[0003]

However, the continuous synthetic slab bridge has the following problems. In the above-mentioned prior art continuous composite slab bridge, a negative bending moment may be generated due to a tensile force acting on the continuous composite slab bridge above the bearings excluding both ends due to an automatic vehicle load or the like. When this negative bending moment is generated, the concrete is weak in tensile force, so there is a problem that cracks occur in the slab concrete of the continuous composite slab bridge.

In view of the above circumstances, it is an object of the present invention to provide a continuous synthetic slab bridge in which cracking of the slab concrete is prevented.

[0005]

A continuous composite deck slab according to the present invention has a steel girder and concrete cast on the upper surface of the steel girder and integrated with the steel girder, and is supported by a bearing. In a continuous synthetic slab bridge in which the synthetic slab bridge is continuous in the longitudinal direction, the cable holding metal fittings provided on the upper surface of the steel girder between the bearings and the concrete above the bearing excluding both ends of the continuous synthetic slab bridge Through the convex part of the bridge, the space between the bearings of the composite deck slab is held by the cable holding metal fittings, and it extends from one end to the other end of the continuous composite deck slab via the concave shape, and the continuous composite floor receives tensile force at both ends. It is characterized by having a cable fixed to the plate bridge.

Here, it is also preferable that the support is made of a hard viscoelastic body.

[0007]

The continuous composite slab bridge of the present invention is provided on the upper surface of the steel girder between the bearings of the synthetic slab bridge via the concrete part above the support except the both ends of the continuous composite slab bridge in a convex shape. Since the cable installed so as to pass through in a concave shape by the cable holding metal fittings penetrates the continuous synthetic floor slab, it is stretched by receiving tensile force at both ends and fixed to the continuous synthetic floor slab, The cable exerts a compressive force on the continuous composite slab bridge to shrink. This compressive force and the tensile force above the bearing excluding both ends, which is caused by an automatic vehicle-mounted load, are canceled to prevent the concrete floor slab from cracking.

[0008]

1 is a side view showing a part of a continuous synthetic slab bridge according to an embodiment of the present invention. Continuous synthetic slab bridge 2 with 3 spans
As for 0, concrete 1 is cast on a continuous steel girder 12 supported by one fixed bearing 4 and three moving bearings 5 on four piers 2, and asphalt 15 is placed on the upper surface of this concrete 1. is set up. In addition, continuous synthetic floor slab 20
Has the structure of the hollow type synthetic slab bridge disclosed in Japanese Patent Publication No. 3-48285.

FIG. 2 is a side view showing a part of the continuous synthetic slab bridge of FIG. 1 in cross section. The concrete 1 shown in FIG. 1 includes a concrete filling portion 10 provided above the fixed bearing 4 and the movable bearing 5, and a polystyrene foam 3 provided in a hollow portion adjacent to the concrete filling portion 10.
And the floor slab concrete 11 provided on the upper surface of the expanded polystyrene 3 and the upper surface of the concrete filling portion 10. Also, the concrete filling parts 10 at both ends
Is provided with a cable sheath 6 for inserting a cable 8 on its side surface, and a cable sheath having a convex shape on the floor slab concrete 11 above the concrete filling portions 10 excluding the concrete filling portions 10 at both ends. 6 is provided. The cable 8 is a concrete filling section 10.
Then, via the cable sheath 6, between the bearings 4 and 5,
The steel girders 12 are held by cable holding metal fittings 7 provided on the upper surface of the steel girders one by one between the bearings and passed through in a concave shape. In this way, the cable 8 passes in a wave shape, and both ends of the cable 8 are pulled by the cable tensioning device 9 and a tensile force is applied to extend the cable 8. This stretched cable 8
Both ends of are fixed to both ends of concrete 1, and cable 8
As a result of the contraction of the
Act on.

FIG. 3 (a) is a bending moment diagram generated by the cable compression force generated in the continuous composite slab bridge shown in FIG. 2, and FIG. 3 (b) is a continuous composite slab bridge shown in FIG. Bending moment due to evenly distributed load that occurs in Fig. 3 (c)
FIG. 4B is a bending moment diagram in which the bending moments shown in FIGS. 3A and 3B are superposed. Figure 3
As shown in (a), due to the compressive force of the cable 8, the continuous synthetic slab bridge 20 is provided near the bearings 4 and 5 except the bearings at both ends.
A positive bending moment is generated that causes a tensile force on the bottom surface of
In the portion between the bearings, a negative bending moment that causes a tensile force is generated on the upper surface of the continuous composite slab bridge 20. on the other hand,
As shown in FIG. 3 (b), when an evenly distributed load such as an automatic vehicle load is mounted, a tensile force is generated on the upper surface of the continuous composite deck slab 20 in the vicinity of the bearings 4 and 5 excluding the bearings at both ends. A negative bending moment is generated, and a positive bending moment that a tensile force is generated on the lower surface of the continuous composite slab bridge 20 is generated between the bearings. Incidentally, FIG. 3 (b) is also a bending moment diagram of the conventional continuous composite floor slab bridge. Here, the bending moment actually generated in the continuous composite slab bridge 20 is shown in FIG.
And the bending moment shown in FIG. 3 (b) is superposed, and the bending moment is as shown in FIG. 3 (c). As shown in Fig. 3 (c), the continuous synthetic floor slab 2
At 0, at least a large negative bending moment does not occur, so that the floor slab concrete 11 is prevented from cracking. Also, along with this, continuous synthetic floor slab 2
The positive bending moment generated at 0 can also be made smaller than the positive bending moment of the conventional continuous composite deck slab shown in FIG. 3 (b).

[0011] Here, when an evenly distributed load such as an automatic vehicle load does not act on the continuous composite slab bridge during construction of the continuous composite slab bridge, the compressive force of the cable causes, for example, the center span of Fig. 3 (a). As described above, a large negative bending moment may occur in the continuous composite slab bridge, and cracks may occur in the slab concrete 11. In order to prevent this, it is preferable to place the slab concrete at a location where a large negative bending moment is generated after fixing the cable by applying a tensile force.

FIG. 4 is a side view showing a partial cross-section of a continuous composite slab bridge according to another embodiment. The same components as those in the above-described embodiment are designated by the same reference numerals, and the duplicate description will be omitted. The cable 8 is held by the two cable holding metal fittings 7 in the vicinity of both ends in the center span of the continuous synthetic floor slab 20 and is held by the cable holding metal fitting 7 in the side spans of both ends rather than in the center span. There is.

FIG. 5A is a bending moment diagram due to the compressive force of the cable generated in the continuous composite slab bridge shown in FIG. 4, and FIG. 5B is a continuous composite slab bridge shown in FIG. Bending moment due to evenly distributed load that occurs in
FIG. 6 is a bending moment diagram in which the bending moments shown in FIGS. 5A and 5B are superimposed. Figure 5
As shown in (a), since the cable holding metal fitting 7 shown in FIG. 2 and the cable holding metal fitting 7 shown in FIG. The bending moment is smaller than that shown in FIG. By crawling the cable 8 in this way,
It is also possible to prevent a large negative bending moment from being generated in the continuous composite slab bridge due to the compressive force and cracking of the slab concrete 11. As shown in FIG. 5 (c), at least a large negative bending moment does not occur in the continuous composite slab bridge 20, and the slab concrete 11 is prevented from cracking. And continuous synthetic floor slab 2
The positive bending moment generated at 0 can also be made smaller than the positive bending moment of the conventional continuous composite deck slab shown in FIG. 5 (b).

Here, if the fixed bearing and the movable bearing are made of hard rubber, the hard rubber causes only shearing deformation without causing compressive deformation, and therefore may have the functions of the fixed bearing and the movable bearing. it can. Therefore, it is preferable that the fixed bearing and the movable bearing can function by one component.

[0015]

As described above, the continuous composite slab bridge of the present invention includes the above-mentioned cable that is stretched and fixed to the continuous composite slab bridge. It is possible to prevent cracks from being generated in the floor slab concrete by canceling out the tensile force due to the automatic vehicle load or the like. The positive bending moment generated in the continuous composite slab bridge can also be made smaller than the positive bending moment of the conventional continuous composite slab bridge.

[Brief description of drawings]

FIG. 1 is a side view showing a part of a continuous synthetic floor slab according to an embodiment of the present invention.

FIG. 2 is a side view showing a part of the continuous synthetic slab bridge of FIG. 1 in cross section.

3 is a bending moment diagram (a) of the continuous composite slab bridge shown in FIG. 2 due to the compressive force of the cable, and a bending moment due to an evenly distributed load generated in the continuous composite slab bridge shown in FIG. Bending moment diagrams in which the bending moments shown in FIGS. (B), (a) and (b) are superimposed on each other (c)
Is.

FIG. 4 is a side view showing a part of a continuous composite slab bridge according to another embodiment in cross section.

5 is a bending moment diagram (a) generated by the continuous composite floor slab bridge shown in FIG. 4 due to the compressive force of the cable, and a bending moment caused by an evenly distributed load generated in the continuous composite floor slab bridge shown in FIG. It is a bending moment figure (c) which overlapped the bending moments shown in Drawings (b), (a), and (b).

[Explanation of symbols]

1 Concrete 3 Styrofoam 4 Fixed bearing 5 Moving bearing 6 Cable sheath 7 Cable holding metal fittings 8 Cable 9 Cable tensioning device 10 Concrete filling part 11 Floor slab concrete 12 Steel girder 20 Continuous synthetic deck bridge

Claims (2)

[Claims] 1. A continuous slab bridge having a steel girder and concrete placed on the upper surface of the steel girder and integrated with the steel girder, the synthetic slab bridge supported by bearings being continuous in the longitudinal direction. In a composite slab bridge, the cable holding metal fittings provided on the upper surface of the steel girder between the bearings and the concrete portion above the support except both ends of the continuous synthetic slab bridge are convexly routed to the composite. It is held between the bearings of the slab bridge by the cable holding metal fitting and extends in a concave shape from one end of the continuous composite slab bridge to the other end, and is fixed to the continuous composite slab bridge by receiving tensile force at both ends. A continuous synthetic slab bridge characterized by being equipped with a cable that is formed. 2. The continuous synthetic deck slab according to claim 1, wherein the support is made of a hard viscoelastic body.