JPH01322047A - Joint method for main reinforcement - Google Patents

Abstract

PURPOSE:To improve the joint strength by forming a hook part consisting of a main reinforcement onto the joint edge surface of a member and fastening the hook parts of the contiguously arranged members by using a cable made of high strength fiber in tension state. CONSTITUTION:The top edge of a main reinforcement 2 is shaped into a hook form, and the main reinforcement 2 is embedded into a precast concrete member 1. The hook part 4 consisting of the main reinforcement 2 is formed at the joint edge surface 3 of the member 1. The hook parts 4 and 4 projecting from the joint edge surfaces 3 and 3 of the contiguously arranged members 1 and 1 are tightened by a cable 5 made of high strength fiber in tension state. Therefore, the concentration to one point of the joint parts is prevented by the hook part 4, and the joint part can be surely charged with concrete, and the joint strength can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for joining main reinforcements of precast concrete.

(Conventional technology) In proceeding with precasting of concrete structures,
It is important to improve the reliability of the joints of precast concrete members, and lap joints, welded joints, etc. have been conventionally used to join the main reinforcement between precast concrete members.

(Problems to be Solved by the Invention) However, in the case of the above-mentioned lap joints and welded joints, the joints are concentrated in one place, making it difficult for concrete to spread, and cracks tend to concentrate on the joint surfaces. have.

An object of the present invention is to provide a method for joining main reinforcements that does not have such disadvantages.

(Means for Solving the Problems) The main reinforcing reinforcement joining method of the present invention involves forming the tips of the main reinforcing bars arranged in each precast concrete member to be joined into a hook shape, and inserting the ends of the main reinforcing bars from the joining end faces of the precast concrete members to be joined. The method is characterized in that it is embedded in a precast concrete member and a hook part is formed on the joint end face, and the hook parts protruding from the joint end face are tied together with a tensioned rope made of high-strength fiber. ) The main reinforcement is a hook part that protrudes from the joint end surface and is made of tension rope made of high-strength fiber. Because only a rope made of high-strength fiber is involved, the concrete can be sufficiently distributed even at the joints.

(Example) Hereinafter, a method for joining main reinforcements of the present invention will be explained with reference to the accompanying drawings.

1 in the figure shows a precast concrete member, and inside the precast concrete member 1 there are main reinforcements 2 made of reinforcing bars.
The tip of each main reinforcement 2 is formed into a hook shape, and the tip is connected to the precast concrete member 1.
The hook portion 4 is embedded in the precast concrete member 1 from the joint end surface 3 to form a hook portion 4 on the joint end surface 3. The main reinforcements 2 of these precast concrete members 1 are connected to the joint end faces 3 and 3 according to the joining method of the present invention.
The hook parts 4 and 4 protruding from each other are connected by tightening a tension rope 5 made of high-strength fiber such as wholly aromatic polyamide fiber. To tension the rope 5, the rope 5 is first connected, for example, between opposing hook parts 4.4.

At this time, the method of connecting the rope 4.4 is, for example, a tie knot, or a net 5.
Connect them in such a way that they become tightly bound when subjected to a tensile force.

Next, a rod-shaped fastener 6 is inserted into the rope 5 connected in this way, the rope 5 is twisted up to a tensioned state, and the fastener 6 is twisted.
is fixed to the stirrup 7 reinforced around the rope 5 using binding wires (not shown) or the like.

Although not particularly shown in the drawings, for the purpose of shear reinforcement, the diagonally opposing hook portions 4 and 4 may be lined with ropes 5.

Furthermore, if the void 8 of the hook portion 4 is filled with a filler 9 such as epoxy resin as shown in the second figure, cracks can be prevented at the joint.

Further, by increasing the length of the hook portion 4 as shown in the third figure, cracks in the joint portion can be dispersed.

The rope 5 used in the joining method of the present invention may be made of not only fully aromatic polyamide fibers such as aramid fibers, but also
Inorganic fibers such as carbon fiber, glass fiber, ceramic fiber,
The rope 5 is made of organic fibers such as polyester fibers, high-strength polyolefin fibers, strong polyamide fibers, strong polyvinyl alcohol fibers, or high-strength fibers such as metal fibers. The length and thickness of the rope 5 are arbitrarily selected depending on the strength required for the joint.

The hook portion 4.4 protruding from the joint end surface 3.3 is connected to a tension rope 5 made of high-strength fiber such as wholly aromatic polyamide fiber.
After making the concrete, pour concrete in place according to the usual method. At this time, if cement paste is applied to the joint end surface 3, the width of the crack on the joint surface will be reduced.

As a result of the experiment, when two reinforcing bars were placed on the tension side as in the illustrated example, when a bending moment was applied that was nearly twice that of a single-piece specimen with two reinforcing bars placed on the tension side,
It was confirmed that it had the respective proof strengths when loaded in a diagonal tension shear and in a pure shear.

(Effects of the Invention) As described above, according to the main reinforcing reinforcement joining method of the present invention, the hook portions of the main reinforcing bars protruding from the joining end surfaces of each precast concrete member to be joined are tied together with a tensioned mesh made of high-strength fibers. Since the concrete is distributed by the hooks instead of being concentrated in one place, and there is only a high-strength fiber mesh between the hooks, the concrete can be spread evenly at the joints. , it has the advantage of being able to easily perform good bonding without concentrating cracks in the bonded area.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of one embodiment of the method for joining main reinforcements of the present invention, FIG. 2 is a plan view of a modified example of the hook portion, and FIG. 3 is a plan view of another modified example of the hook portion. 1... Precast concrete member 2... Main reinforcement 3... Joint end surface 4... Hook portion 5... Rope 6... Fastener 7... Stirrup 8... Gap 9... Filler

Claims (1)

[Claims] The tip of the main reinforcement arranged in each precast concrete member to be joined is formed into a hook shape, and the tip is buried in the precast concrete member from the joint end face of the precast concrete member to form a hook portion on the joint end face. , a method for joining main bars, characterized in that the hook parts protruding from the joint end faces are tied together with a tensioned rope made of high-strength fibers.