JPH0932313A - Reinforcing work of concrete beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce a beam to securely anchor the ends of reinforcing materials and realize a design as a reinforced concrete structure and directly transfer the stresses on the reinforcing materials to the supporting points without transmitting the stresses to the concrete and reinforce the beam against shearing forces at the same time. SOLUTION: Anchorage holes 15 are bored in a concrete beam 13 and the anchorage part 17a of a reinforcing material 17 like a reinforcing rod or a fiber reinforcing resin bar is inserted in the anchorage hole 15 to fix the reinforcing material 17 with grout 18. A steel material as a transmission structure for shearing forces is set at the end of a beam to reinforce the beam against shearing forces. In this transmission structure for shearing forces, slits are made in the slab at the end of the concrete beam 13 and the ends of concrete beam 13 are held by the steel materials reinforcing inserted in the slits.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing concrete beams of viaducts such as roads and railways.

[0002]

2. Description of the Related Art In recent years, on roads with viaducts, overloading of large trucks causes more than the designed load to be applied, so it is necessary to reinforce floor boards and beams. From the recent situation, the floorboard is designed as 20ton, and it is supposed to be 25ton from now on, and it is necessary to reinforce the floorboard and the beam.

Conventionally, as methods for reinforcing such beams, there are a steel plate bonding method for reinforcing the tensile side with a steel plate and an FRP bonding method for reinforcing the tensile side with FRP (fiber reinforced resin).

Among these, the steel plate bonding method is shown in FIG. 18, in which the steel plate 2 is bonded to the tensile surface of concrete and is integrated with the existing concrete beam 1 to improve the bending resistance. A resin material such as an epoxy type is used. In this case, there are a crimping method and an injecting method depending on the bonding method, but in the example shown in the figure, the pressing mechanism is composed of the L-shaped steel 7 and the pressing wood 5 with the anchor bolt 4 and the steel plate 2 attached to the pressing side by the crimping method. are doing.

FIG. 19 shows an FRP bonding method, in which a plate of FRP8 is used instead of the steel plate 2 and is fixed by an anchor bolt 4, but a gap between the FRP 8 and the floor plate 1 is bonded by an injection pipe 9. An epoxy resin for injection as the agent 3 is filled. In the figure, 10 is a spacer for securing the gap, 11 is an air vent pipe, and 12 is an epoxy resin for putty.

[0006]

[Problems to be Solved by the Invention] Such steel plate and FR
If the reinforcing material of P is attached to the lower surface of the beam with an adhesive to reinforce it, a sufficient adhesive effect cannot be obtained if the concrete to be attached is fragile or deteriorated, and after a long time has passed. It often comes off.

Since the end of the reinforcing material is not fixed by the steel plate or FRP, the reinforcing material cannot be regarded as a reinforcing bar and a reinforcing design as a reinforced concrete structure cannot be established.

In any case, the reinforcement on the tension side of the beam is achieved, but not the shear reinforcement. Further, the stress that the tensile reinforcing material bears is transmitted to the fulcrum through the concrete and is not directly transmitted to the fulcrum, so that the reinforcing effect cannot be ensured.

An object of the present invention is to reinforce the beam by eliminating the disadvantages of the above-mentioned conventional example, to ensure the fixing of the end portion of the reinforcing material, and to establish the design as a reinforced concrete structure. It is an object of the present invention to provide a reinforcing method for a concrete beam which can directly transmit the stress that the material bears to the fulcrum without passing through the concrete and can also perform shear reinforcement.

[0010]

According to the present invention, in order to achieve the above object, a fixing hole for fixing is formed in a concrete beam, and a fixing portion of a reinforcing material such as a reinforcing bar or a fiber-reinforced resin rod is provided in this fixing hole. Inserting and fixing with a grout, steel material as a shear transmission mechanism is set at the beam end for shear reinforcement, but this shear transmission mechanism has a slit opened in the slab at the beam end and inserted here The gist is to hold the edges.

According to the present invention, since both ends of the reinforcing material are fixed, the reinforcing design can be performed in accordance with the design method of the reinforced concrete structure. That is, it is possible to design both the existing reinforcing bars of the concrete beam and the added reinforcing material as tensile reinforcing materials. Furthermore, the shear transmission mechanism enables shear reinforcement and transmission of load to the fulcrum.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. The present invention, as shown in FIG. 15, is a concrete beam which is a T-shaped beam of reinforced concrete of viaduct.
The side and cross section of this concrete beam 13 for reinforcing 13 are shown in FIGS. 16 and 17, where 14 is an existing reinforcing bar.

In the present invention, as shown in FIGS. 1 and 2, the concrete beam 13 is provided with a fixing hole 15 for fixing. In the illustrated example, the fixing hole 15 is located at the end of the beam, but the present invention is not limited to this, and a plurality of fixing holes 15 can be opened, but if they are concentrated on the same cross section of the end of the beam. It may become a weak point, so it is better to alternately shift them appropriately.

As shown in FIGS. 3 and 4, concrete beams
Drive the required amount of shear key 16 on the lower surface of 13. A post-installed anchor is often used as the shear key 16, but its function is merely transmission of shear force. As the material, steel, FRP rod or the like is used.

As shown in FIGS. 5 and 6, the fixing portion 17a of the reinforcing member 17 such as a reinforcing bar or a fiber-reinforced resin rod is provided with the fixing hole 15a.
And fix it with the fixing grout 18. This reinforcement
A concrete beam 17 is used to reinforce the tension side of the concrete beam 13 and processed into a wide U-shape so that both ends can be inserted into the fixing holes 15 as described above. If the length is short and the length is insufficient, a lap joint, welded joint, mechanical joint, etc. shall be provided in the middle.

As the material of the reinforcing material 17, reinforcing bars, epoxy resin coated reinforcing bars, fiber-reinforced resin rods (FRP rods)
As the reinforcing fiber, carbon fiber, aramid fiber, glass fiber, polyethylene fiber, nylon fiber, polyvinyl alcohol fiber or the like is used.

As the fixing grout 18, epoxy resin for injection, cement paste, cement paste containing expansive admixture, cement paste containing fine aluminum powder and the like are used. Further, a mesh-shaped FRP may be arranged along the reinforcing material 17.

As shown in FIGS. 7 and 8, the concrete beam 13
A formwork 19 is installed on the lower surface of the mold, and a concrete or mortar injection hole 20 is provided in the formwork 19.

Then, as shown in FIG. 9 and FIG.
Pour concrete or mortar 24 through
These are normal aggregates or lightweight aggregates, and are obtained by adding any one or a plurality of or all of an expansive material, an aluminum fine powder, a high-performance AE water reducing agent, and a thickening agent. Furthermore, both concrete and mortar 24 should be highly fluid.

When the mold 19 is released from the mold, the reinforcing material 17 is covered with concrete or mortar 24 as shown in FIGS. 11 and 12, and the tensile reinforcement is completed, but as shown in FIGS. Then, a steel material as the shear transmission mechanism 21 is set so as to surround the periphery of the beam end portion to provide shear reinforcement. In the illustrated example, the shear transmission mechanism 21 includes a body 21a having a cross section of a horizontal U shape,
A combination of a lid member 21b that closes the open surface underneath is used.

The shear transmission mechanism 21 has a slit 23 opened in the slab 22 at the end of the concrete beam 13, and the shear transmission mechanism 21 is inserted through the slit 23 to end the concrete beam 13. Shall be held.

[0022]

As described above, the method of reinforcing concrete beams according to the present invention ensures the anchoring of the end portions of the reinforcing material so that the design as a reinforced concrete structure can be established, and the stress that the reinforcing material bears. Can be directly transmitted to the fulcrum without going through concrete, and shear reinforcement can also be performed.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a first step of a method for reinforcing a concrete beam according to the present invention.

FIG. 2 is a vertical sectional side view showing a first step of the concrete beam reinforcing method of the present invention.

FIG. 3 is a vertical sectional front view showing a second step of the concrete beam reinforcing method of the present invention.

FIG. 4 is a vertical sectional side view showing a second step of the concrete beam reinforcing method of the present invention.

FIG. 5 is a vertical sectional front view showing a third step of the concrete beam reinforcing method of the present invention.

FIG. 6 is a vertical cross-sectional side view showing a third step of the concrete beam reinforcing method of the present invention.

FIG. 7 is a vertical sectional front view showing a fourth step of the method for reinforcing a concrete beam of the present invention.

FIG. 8 is a vertical cross-sectional side view showing a fourth step of the concrete beam reinforcing method of the present invention.

FIG. 9 is a vertical sectional front view showing a fifth step of the method for reinforcing a concrete beam of the present invention.

FIG. 10 is a vertical cross-sectional side view showing a fifth step of the concrete beam reinforcing method of the present invention.

FIG. 11 is a vertical sectional front view showing a sixth step of the method for reinforcing a concrete beam of the present invention.

FIG. 12 is a vertical sectional side view showing a sixth step of the method for reinforcing a concrete beam of the present invention.

FIG. 13 is a vertical cross-sectional front view showing a seventh step of the concrete beam reinforcing method of the present invention.

FIG. 14 is a vertical cross-sectional side view showing a seventh step of the concrete beam reinforcing method of the present invention.

FIG. 15 is a vertical sectional side view of a viaduct for a concrete beam.

FIG. 16 is a vertical front view of a concrete beam.

FIG. 17 is a vertical sectional side view of a concrete beam.

FIG. 18 is a vertical sectional side view showing a conventional example.

FIG. 19 is a vertical sectional side view showing another conventional example.

[Explanation of symbols]

1 ... Concrete beam 2 ... Steel plate 3 ... Adhesive 4 ... Anchor bolt 5 ... Pressed wood 7 ... L-shaped steel 8 ... FRP 9 ... Injection pipe 10 ... Spacer 11 ... Air vent pipe 12 ... Putty epoxy resin 13 ... Concrete beam 14 ... Existing reinforcing bar 15 ... Fixing hole 16 ... Shear key 17 ... Reinforcing material 17a ... Fixing part 18 ... Fixing grout 19 ... Formwork 20 ... Injection hole 21 ... Shear transmission mechanism 21a ... Main body 21b ... Lid material 22 ... Slab 23 ... Slit 24 … Concrete or mortar

Claims (1)

[Claims] 1. A fixing hole for fixing is formed in a concrete beam, and a fixing portion of a reinforcing material such as a reinforcing bar or a fiber-reinforced resin rod is inserted into this fixing hole and fixed with a grout to fix a steel material as a shear transmission mechanism. The shear transmission mechanism is set at the end of the beam for shear reinforcement, but this shear transmission mechanism is characterized by forming a slit in the slab at the end of the beam and inserting it into the slab to hold the end of the beam. .