JP2001182015A - Construction method of synthetic floor slab bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a lack of reliability by welding a steel plate over a lower end surface of a web of T shape steel, the difficulty of acquiring CT shape steel for arranging a projection on the upper flange at rolling time and a weight increase in an open cross-sectional steel beam by heightening the beam height. SOLUTION: H shape steel having a bolt inserting hole is arranged in parallel at a required interval on an upper flange; a bottom steel plate is joined by a high tension bolt between lower end surfaces of a lower flange of the respective H shape steel; angle steel arranged at a required interval in the lengthwise direction on adjacent upper flange under surfaces is fastened and fixed by a nut from the upper flange under surfaces by using the high tension bolt having a long shaft part inserted from an upper surface of the bolt inserting hole to form parallel open cross-sectional steel beams; an upper main reinforcement is arranged in an upper position more than an upper surface of the upper flange; and concrete is placed up to the upper position of the main reinforcement from an upper surface of the bottom steel plate with the open cross-sectional steel beams as common timbering and a form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a composite deck slab having a composite structure of steel and concrete, in which a parallel-section steel girder made of H-shaped steel and a bottom steel plate is integrated with concrete.

A composite slab bridge using a composite structure of steel and concrete has a structure in which tensile stress is borne by steel material and compressive stress is borne by concrete, and the girder height can generally be reduced.

[0003] As a conventional composite slab bridge, CT sections having projections on the upper surface of a flange are arranged in parallel at required intervals, and a steel sheet is welded over the lower end face of the web of each CT section to form an open section steel. Of a structure that forms a girder
No. 61443) and a steel plate and a lower end surface of a web are welded to the steel plate, and a plurality of T-beams arranged in parallel at a required interval and a plurality of T-beams adjacent to each other are installed between the upper flanges. And a structure formed of the T-shaped steel and concrete cast on the disposal form (Japanese Unexamined Patent Publication No. 3-28).
No. 6009) is known.

The former attempts to ensure the integrity of the open section steel girder and the concrete by means of projections provided on the upper surface of the upper flange of the CT section steel at the time of rolling, and the latter aims to secure the integrity of the closed section steel girder and the concrete. Is secured by a stopper provided on the upper surface of the T-shaped steel upper flange.

[0005]

The problem common to both of these is that the steel plate is welded over the lower end surface of the web of each T-section.

[0006] Generally, the welding operation largely depends on the skill of the welder, and thus lacks reliability. In addition, changes in strain and hardness caused by welding also cause a reduction in fatigue durability.

[0007] In the former case, a blast furnace manufacturer having limited projections provided on the upper flange surface thereof at the time of rolling is difficult to obtain. Since the size of steel is limited, it is difficult to select an appropriate size in design, and in the case of the latter, which is provided on the upper surface of the T-shaped steel upper flange, concrete is removed from the upper surface of the T-shaped steel upper flange. The distance to the upper edge of the compression is required to be greater than the height of the slip stopper.In addition to the girder height, the weight of the cast concrete increases, and the weight of the closed-section steel girder supporting this weight also increases. May be impaired.

[0008]

According to the present invention, the above-mentioned problems are to be solved by the following means.

First, basically, H-section steels having bolt insertion holes in the upper flange are arranged in parallel at required intervals, and the bottom steel sheet is formed between the lower end faces of the lower flanges of the respective H-section steels by using a torcia-type high-strength bolt. At the same time, the angle iron that is arranged at the required interval in the longitudinal direction on the lower surface of the adjacent upper flange is tightened with a nut from the lower surface of the upper flange using a high-strength bolt with a long shaft part inserted from the upper surface of the bolt insertion hole Fixed to form a parallel open section steel girder, and arrange the upper main rebar at a position higher than the upper surface of the upper flange, the open section steel girder as a common support and form, from the top of the bottom steel plate And a method of constructing a composite floor slab bridge, wherein concrete is cast to a position above the upper main reinforcing bar.

This method of constructing a composite floor slab bridge achieves the integration of concrete with a parallel open section steel girder by combining a high strength bolt and an angle iron having a shaft section provided below an H-shaped steel upper flange. is there. Since high strength bolts and angle irons are highly marketable and their sizes are abundant, they can be obtained in necessary amounts at relatively low prices. In addition, the head of the high-strength bolt projects on the upper surface of the upper flange.
Since it is about 0 mm, the distance from the upper surface of the upper flange to the upper edge of the concrete compression can be reduced to the minimum cover of the concrete.

Next, in the method of constructing a composite floor slab bridge, a part of the concrete between the lower position of the tip of the shaft portion of the high strength bolt having a long shaft portion and the upper surface of the bottom steel plate is hollowed or replaced with a foamed resin. A method for constructing a composite deck bridge is provided.

This method of constructing a composite slab bridge is suitable for a composite slab bridge having a long span and a large girder height. In the composite deck bridge, since the concrete is completely filled in the open section steel girder, the concrete weight per unit area increases accordingly, and the parallel open section steel girder supporting this weight also increases. When the span exceeds 20 m, the weight per unit area of the parallel open-section steel girder increases sharply, and the economic efficiency is remarkably impaired. When the span exceeds 30 m, the construction of a composite floor slab bridge completely filled with concrete is economical. And mechanically difficult. This method of constructing composite slabs is sufficient to solve these.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

First, a first embodiment will be described with reference to FIGS.

The H-shaped steel members 2 having the bolt insertion holes 1a are arranged in parallel on the upper flange 1 at required equal intervals. A high-strength bolt 7 having a long shaft portion that is joined by a force bolt 5 and that has an angle iron 6 disposed on the lower surface of the adjacent upper flange 1 at intervals of 1 to 4 m in the longitudinal direction and inserted through the upper surface of the bolt insertion hole 1a. It is tightened and fixed with a nut 7b from the lower surface of the angle iron flange 6a, and for the bolt insertion hole 1a where the angle iron 6 is not arranged, the high-strength bolt 7 with a long shaft portion inserted from the upper surface is attached to the lower surface of the upper flange 1. Then, the steel girder is tightened and fixed with a nut 7b to prevent slippage and a parallel open section steel girder.

The parallel open section steel girder is transported to the site where it is to be erected, and is erected on a predetermined abutment. Then, the upper main reinforcing bar 8 is arranged, and the parallel open section spar is used as a common supporter and formwork for the bottom steel plate 4. Concrete 9 is cast from the upper surface to a position slightly above the upper reinforcing bar 8 to construct a composite slab bridge.

The cast concrete 9 may be ordinary concrete having a compressive strength of 27 N / mm ² or more after a material age of 28 days, but from the viewpoint of preventing cracks from occurring due to drying shrinkage of the concrete 9. It is preferable to use expansive concrete to which about 30 kg / m ^{3 of} expansive cement admixture is added.

The composite slab bridge thus constructed is
By joining the bottom steel plate 4 with the torcia-type high-strength bolt 5 across the lower end surface of each H-shaped steel lower flange 3, and
By joining angle steel flanges 6a to the lower surface of the upper flange 1 at required intervals with high-strength bolts 7 having long shafts, a parallel open section steel girder is formed without welding steel members.

The angle steel 6 joined to the upper flange 2 at a required interval by a high-strength bolt 7 having a long shaft portion restrains the deformation of the upper flange, and is used when erection of a parallel open section steel girder and concrete casting. To prevent the upper flange 1 from buckling at
Conventionally, an intermediate cross girder attached to an H-section steel web in a longitudinal direction of 6 m or less is unnecessary, and labor saving in factory production and safety in construction can be achieved.

Further, after the concrete 9 has been hardened,
Since a large bending stiffness can be obtained by combining a concrete 9 and a parallel open section steel girder with the long high-strength bolt 7 and the angle iron 6 fixed to the upper flange 1, the girder height ratio (girder height / span) is It can be 1/25 to 1/40.

Next, another embodiment of the present invention will be described with reference to FIGS. 3 and 4, and still another embodiment will be described with reference to FIGS. 5 and 6. FIG. In this embodiment, a part of the concrete between the lower position of the tip of the shaft portion of the high-strength bolt having a long shaft portion and the upper surface of the bottom steel plate is replaced with foamed resin. The replacement may be hollow.

In FIGS. 3 and 4, the composite slab bridge is formed by inserting a reinforcing steel plate 10 from the tip of the shaft portion 7c of the high-strength bolt 7 having a long shaft portion to the tip of the shaft portion 7c of the high-strength bolt. A nut 7d is attached, a wire mesh reinforcing bar 11 is arranged above the reinforcing bar supporting steel plate 10, and a very light polystyrene foam 12 having a specific gravity of 0.1 or less is filled from the upper surface of the bottom steel plate 4 to a position slightly below the nut 7d. The concrete 9 extends from the upper surface of the Styrofoam 12 to a position slightly above the upper main reinforcing bar 8.
It is built by casting.

5 and 6, the composite floor slab bridge has an expanded metal 13 and a large-sized washer 7e inserted through the tip of a shaft 7c of a high-strength bolt 7 having a long shaft, and a long shaft. A nut 7d is attached to the tip of the shaft portion 7c of the force bolt 7, and the nut 7
d, a very light styrofoam 12 having a specific gravity of 0.1 or less is filled to a position slightly below d.
The concrete is cast from the upper surface of 2 to a position slightly above the upper main reinforcing bar 8.

As described above, in the synthetic deck bridge constructed in the above two embodiments, since a part of concrete is replaced with a synthetic resin foam or hollow, the entire weight can be reduced. In addition, the economic burden can be reduced.

Next, an embodiment of the joint in the bridge axis direction of the bottom steel plate of the parallel open section steel girder of the composite slab bridge by the construction method according to the present invention is shown in FIGS.

In the composite deck slab according to the above-described construction method, when transporting to the site where the parallel open-section steel girder is to be erected, and when erection on a predetermined abutment, legal restrictions on transportation and capacity of the erection crane. Therefore, it becomes necessary to divide the parallel open section steel girder into blocks each having a width of about 2.5 m.

Therefore, here, the blocks are joined by high-strength bolts or an adhesive without welding the steel members even when the blocks are integrated again.

The structure shown in FIG.
A joint bottom steel plate 14 having a thickness equal to or greater than that of the bottom steel plate 4 is fastened to the upper surface of the joint with a torcia-type high strength bolt 5.

The structure shown in FIG.
A joint bottom steel plate 14 having a thickness equal to or greater than that of the bottom steel plate 4 is joined to an upper surface of the base plate with an adhesive 15. The adhesive includes a low-viscosity high-strength epoxy resin-based adhesive and a two-component mixed acrylic resin-based adhesive.

Since the present invention is configured as described above, it has the following effects.

In the first and second aspects, no welding work is required, so that a decrease in reliability due to welding and a decrease in fatigue durability due to a change in strain or strength can be avoided.

The construction is such that the parallel open-section steel girder and concrete are integrated by combining a high-strength bolt having a shaft portion provided below the upper flange of the H-section steel and the angle iron, so that it has high marketability and size. From where abundant high-strength bolts and angle irons can be used, the required quantities can be obtained relatively inexpensively.

The angle steel, which is joined at a required interval with a high-strength bolt having a long shaft portion of the upper flange, restrains the deformation of the upper flange, and the seat of the upper flange during the installation of the parallel open section steel girder and the concrete casting. Prevent buckling.

The head of the high-strength bolt protrudes from the upper surface of the upper flange. Since the height of the protrusion is usually about 20 mm at the maximum, the distance from the upper surface of the upper flange to the compressed edge of the concrete is reduced to the minimum cover of the concrete. Can be smaller.

According to the second aspect of the present invention, since a part of the concrete between the lower position of the tip of the high-strength bolt having a long shaft and the upper surface of the bottom steel plate is made hollow or replaced with a foamed resin, an open-section steel girder is provided. The amount of concrete to be filled into the bridge is reduced, and even in the case of a composite deck bridge having a long span and a large girder height, the weight burden and economic burden can be sufficiently reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a composite slab bridge showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of a composite slab bridge showing another embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a cross-sectional view of a composite deck bridge showing still another embodiment of the present invention.

FIG. 6 is a sectional view taken along line CC of FIG. 5;

FIG. 7 is a cross-sectional view showing an embodiment of a joint portion of a bottom steel plate in the bridge axis direction of the composite floor slab bridge according to the construction method of the present invention.

FIG. 8 is a cross-sectional view showing another embodiment of the joint portion of the bottom steel plate in the bridge axis direction of the composite slab bridge according to the construction method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper flange 1a Bolt insertion hole 2 H-shaped steel 3 Lower flange 4 Bottom steel plate 5 Torcia type high strength bolt 6 Angle steel 6a Angle steel flange 7 High strength bolt with long shaft 7a Washer 7b Nut 7c High strength bolt shaft Part 7d Mounting nut at the tip of the shaft part 7e Large size washer 8 Upper main reinforcing steel 9 Concrete 10 Reinforcing steel support steel plate 11 Wire mesh reinforcing steel 12 Styrofoam 13 Expanded metal 14 Joint bottom steel plate 15 Adhesive

Claims (2)

[Claims] 1. An H having a bolt insertion hole in an upper flange.
The section steels were arranged in parallel at required intervals, and the bottom steel plate was joined with the torcia-type high-strength bolts between the lower end faces of the lower flanges of each H-section steel, and arranged at required intervals in the longitudinal direction on the lower surface of the adjacent upper flange. Using a high-strength bolt with a long shaft part inserted from the upper surface of the bolt insertion hole, the angle iron is tightened and fixed with a nut from the lower surface of the upper flange to form a parallel open section steel girder,
Also, an upper main reinforcing bar is arranged at a position higher than the upper surface of the upper flange, and concrete is struck from the upper surface of the bottom steel plate to a position above the upper main reinforcing bar by using the open section steel girder as a common support and formwork. A method of constructing a composite floor slab bridge, characterized by being installed. 2. The synthetic floor according to claim 1, wherein a part of the concrete between the lower portion of the tip of the shaft portion of the high strength bolt having a long shaft portion and the upper surface of the bottom steel plate is replaced with a hollow or foamed resin. How to build a bridge.