JPH0525886A - Composite beam - Google Patents

Abstract

PURPOSE:To make a lengthened span available by a method wherein RC structure parts are provided to the center and on both end parts of a beam made of an H beam, tendons are arranged between both end parts and between the flanges of the H beam, and prestress is applied therewith. CONSTITUTION:An H beam 1 is connected at its both ends respectively to columns 6 and 6. A plurality of main reinforcements 3 and stirrups 4 are arranged between the upper and the lower flanges 2 on both sides of the web of the H beam 1, concrete 9 is cast thereto and stiffeners 10 are fixed to both end parts, and thereby RC structure parts 7a and 7b are formed. Prestressing wires 8 are provided along both sides of the web of the H beam 1, penetrating through the RC structure parts 7a and 7b and the stiffeners 10, and are anchored to the stiffeners 10 on the outside. Then prestress is induced with the prestressed concrete wires 8 after the concrete is hardened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite beam in which a reinforced concrete structure (referred to as RC structure) is built in a web portion between flanges of H-section steel.

[0002]

Problems to be Solved by the Invention As shown in FIGS.
In the web portion between the flanges 2 and 2 of the H-shaped steel 1, the main bar 3,
Synthetic burrs having an RC structure reinforced with ribs 4 or an RC structure reinforced with main bars 3 and vertical bars 5 have been put into practical use. These conventional synthetic burrs can be improved in rigidity, proof strength, etc. by incorporating an RC structure, but they have a problem that they are heavier than steel beams and have a long span, which is difficult.

The present invention has been made in view of the above problems. The purpose is to propose a synthetic beam that is relatively lightweight, has a large yield strength, and enables a long span.

[0004]

This composite beam is a composite beam in which a reinforced concrete structure is built in between flanges of H-section steel. In the reinforced concrete structure built-in part, there are beam end parts and central part, and beam end parts. It is characterized in that a tension material is arranged between the flanges between them to introduce prestress.

[0005]

This composite beam is made lightweight by incorporating RC structures only in the central portion and both end portions which require relatively large rigidity and proof stress. By introducing prestressing with tension material, it is possible to increase the proof stress and, in combination with the weight reduction, it is possible to extend the span. Further, the RC structure portions built in the central portion and both end portions hold the tendon and contribute to the introduction of prestress by the tendon.

[0006]

EXAMPLE The composite flash of the example shown in FIG. 1 has both ends of H-section steel 1 joined to columns 6, RC structures 7a and 7b are provided at the center and both ends thereof, and two RCs are provided between both ends. Alternatively, it is configured by arranging several PC steel wires 8.

Each of the RC structure parts 7a and 7b has four or several main bars 3 and stir bars 4 arranged between the upper and lower flanges 2 and 2 on both sides of the web of the H-shaped steel 1 as shown in FIG.
Concrete 9 is filled, and stiffeners 10 shown in FIG. 3 are fixed to both ends of the concrete 9. Each PC steel wire 8 is shown in Figs.
As shown in FIG. 4, the RC structure 7a, 7b and the through hole 11 of the stiffener 10 are passed along both sides of the web of the H-shaped steel 1, and both ends of the RC structure 7b are fixed and reinforced on the outer stiffener 10 surface. After the concrete 9 is hardened, prestress is introduced.

Although the main reinforcement 3 and the stirrup reinforcement 4 are arranged in the RC structure, the main reinforcement is not necessary when only increasing the rigidity.

[0009]

The present invention is as described above. Despite the fact that this composite beam is relatively lightweight, the central part and both ends, which are required to have high rigidity, have RC structures built in and are reinforced to have a large yield strength. Therefore, local buckling of the H steel is suppressed, and prestress is introduced between both ends by a tension material, so that a long span can be achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a composite beam according to an embodiment.

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

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

FIG. 4 is a sectional view taken along line CC of FIG.

FIG. 5 is a sectional view of a conventional composite beam.

FIG. 6 is a sectional view of a conventional composite beam.

[Explanation of symbols]

1 ... H-section steel, 2 ... Flange, 3 ... Main bar, 4 ... Stirrup bar,
5 ... Vertical stripes, 6 ... Pillars, 7a, 7b ... RC structure, 8 ... PC
Steel wire, 9 ... Concrete, 10 ... Stiffener, 11 ... Through hole.

Claims (1)

Claim: What is claimed is: 1. In a composite beam having a reinforced concrete structure built in between flanges of H-section steel, the reinforced concrete structure built-in part is at both ends of the beam and the center part, and the flange between both ends of the beam. Synthetic burrs characterized by having a tension material arranged between them and introducing prestress.