JPH01214668A - Preassembling method for beam reinforcement - Google Patents

Abstract

PURPOSE:To keep beam strength constant as well as to facilitate construction in size as specified, by arranging a joint almost in the center of a span space when plural numbers of main reinforcement are joined together by welding with pressure, while making at least one piece of the main reinforcements set to such length as providing some contraction allowance at the time of pressure welding. CONSTITUTION:For example, on a slab S, when two pieces of beam reinforcements A1, A2 are joined together and peripheral sides B1, B2 are constructed at both sides of them, a U-shaped main reinforcement 14 of the reinforcement B2 is set to be longer as much as l1 than length l out of a reinforcement constituent body A, setting it down to contraction allowance at the time of welding with pressure. When the reinforcement A1 is fixed and a main reinforcement 7 of the reinforcement A1 is welded to another main reinforcement 7 of the reinforcement A2, the main reinforcement 7 in the X direction moves as much as the contraction allowance l1, and each main reinforcement joint J of these reinforcements A1, A2 has set length out of the constituent body 1A to l, so that it comes to be situated almost at the center between joints 11 in consequence. Consequently, strength is kept constant, and length of each joint body of these reinforcements A1, A2, B1 and B2 is constructible in size as specified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for pre-assembling beam reinforcing bars constituting beams of reinforced concrete buildings.

[Conventional technology and its problems] When pre-assembling beams for reinforced concrete buildings,
After joining multiple main bars, place reinforcing bars such as stirrups on the sides, incorporate a beam reinforcing cage, place a beam formwork around the beam reinforcing bars, and pour concrete inside it. ing.

There are usually the following three methods for joining a plurality of main reinforcements.

■A welded joint that joins the joint end faces of main reinforcement by welding them together.

■Screw type joint that connects the joint ends of main reinforcement with screws.

■A pressure welding joint in which the joint surfaces of the main reinforcements are pressed against each other while heated or at room temperature.

Among these joining methods, welded joints and threaded joints can join the main reinforcements with almost no shrinkage, so they have the advantage of being excellent in workability, but are expensive. Therefore, although the pressure welding joint described above is advantageous in this respect,
There remains the problem that shrinkage occurs during opposite surface joints and the main reinforcement shortens, resulting in cases where it is not possible to obtain the main reinforcement length according to the dimensions.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and involves first assembling beam reinforcing bars in which a plurality of main reinforcements are joined together by pressure welding, and reinforcing bars are incorporated therein. When joining each of the main reinforcements by pressure welding, the joint part is placed approximately midway between the spans, and at least one of each main reinforcement is
The length is set to allow for shrinkage that occurs during pressure welding.

[Example 1] Hereinafter, an example of the method of the present invention will be described with reference to FIGS. 1 to 9.

In Fig. 1, S is a slab of a building, A is a plurality of beam reinforcing bars set on the slab S and connected to each other (hereinafter simply referred to as beam reinforcing bars), B is a plurality of beam reinforcing bars set on the outer periphery of the slab S, These are the outer beam reinforcing bars that are joined to each other and to the beam reinforcing bars A, and the reinforcement procedure for assembling these beam reinforcing bars A and B first will be described below.

11. Basket assembly of beam reinforcing bars A The beam reinforcing bars A have two reinforcing bar structures IA each extending in the X-Y directions orthogonal to each other, which are incorporated in a protruding shape.

■First, as shown in Figure 2, pour concrete 1 to ensure a level in the rebar pre-assembly yard L in accordance with the dimensions of the wells to the beam reinforcement, and on the surface of this concrete 1, A parallel positioning line 2.2 corresponding to the width of the reinforcing bar ++It adult IA is drawn by marking out.

(2) A plurality of main reinforcing bars 3 as shown in FIGS. 3 and 4 are placed on the lines 2.2 at appropriate intervals in the longitudinal direction of these lines 2.2.

This main reinforcement frame 3 has a pair of posts 4.4 erected on the outside of the line 2.2, hooks 5 attached at two locations at the same height of both posts 4.4, and The rack is composed of a vibro, 6, which is passed between hooks 5 of the same height.

■A plurality of main reinforcing bars 7 (in this case, four each on the top and bottom) are arranged between the vibrators 6 of the main reinforcing bars 3 installed along the longitudinal direction of the line 2.2. As a result, the main reinforcements 7 are arranged to intersect with each other in the X-Y direction, but in this case, as shown in FIG. 1, the main reinforcements 4 in the X direction are arranged above the main reinforcements 4 in the Y direction.

(2) A pair of street rulers 8 are installed at any position on the line 2.2, as shown in FIG. 5, so as to sandwich the main reinforcement 7. As you can see, the ruler 8 consists of an L-shaped angle, and the short part is
It is fixed to the concrete violet with anchor bolts. As described above, the outermost main reinforcing bars 7 of the main reinforcing bars 7 come into contact with the ruler 8, and the reinforcing bar structure IA is positioned in the width direction. Next, as shown in FIG. 6, the intervals between the main reinforcements 7 in the width direction are set equally by pitch caps 9, and a large number of stirrups 10 are placed on the upper, lower and outer main reinforcements 7 along the longitudinal direction of the main reinforcements 7. Wind multiple times.

The above main reinforcement 7, pitch cap 9 and stirrup! 0
As shown in FIG. 1, the reinforcing bar structure IA is constituted by these structures IA, and as shown in FIG. 1, two of these structures IA extend in the X and Y directions, are incorporated in a state where they intersect with each other, and are laterally installed on the beam reinforcing bars.

As shown in FIG. 7, ring-shaped reinforcing bars (hoops in the beams) are placed between the stirrups 10 arranged on both sides of the joints 11 at the four joints II where the reinforcing bar structures IA intersect. ) 12, waste concrete! Upper pillar ink (not shown)
Make multiple turns to match.

■Subsequently, as shown in Fig. 8, a stop plate 12 is installed at one end of the reinforcing bar structure IA by fixing it to the waste concrete concrete 2 with an anchor bolt, and one end of each main reinforcement 7 is attached to this stop plate z2. Align both ends of main reinforcement 7 by butting them together. Here, the lengths of the four ends of the reinforcing bar structures IA that protrude to the outside are all set to the same length a.

Further, on the other end side of the reinforcing bar structure lΔ, a slip prevention plate 13 is installed by fixing to the waste concrete l, which abuts the ends of the lower main reinforcing bars 7 and prevents these main reinforcing bars 7 from shifting.

As described above, the beam reinforcing bars A are assembled into a cage in a protruding shape.

■Cage assembly of the outer reinforcing bars B After installing one reinforcing bar structure IA as described above, as shown in FIG. 1, at both ends of this structure IA,
Complete body! U-shaped main line at right angles to! 4 are incorporated, and one set of 0-shaped main reinforcements 14 are tied together with stirrups 10. Between each U-shaped main bar 14 of one set, the reinforcing bar h'4
The spacing between the main reinforcements 7 in the width direction of the adult IA is the same, and the spacing between the sets is parallel to the reinforcing bar adult! It is the same as between A.

Here, the length of the 0-shaped main reinforcement 14 inside the reinforcing bar structure IA (on the beam reinforcing bar A side) is set to 4, which protrudes to the outside of the reinforcing bar structure IA in the beam reinforcing bar A, as shown in FIG.
The length of the end is set as e.

Subsequently, as shown in FIG. 9, the beam reinforcing bars A (A , , A , in the same figure) are placed on the slab S.
The procedure for constructing a beam reinforcing bar by joining two beam reinforcing bars and joining outer peripheral beam reinforcing bars B (designated as B1 and B in the figure) on both sides will be explained.

Here, the outer peripheral beam reinforcing bar B on the right side in Fig. 9! The 0-shaped main bar 14 is located inside the reinforcing bar component IA (beam reinforcing bar A
The length of (1111) is set to be longer than Q by QI. This length B is each reinforcing bar A 1% A t, B
This is the shrinkage margin when the main reinforcements 7 of lsB are pressed together and the main reinforcements 7 and 0-shaped main reinforcements 14 are pressed together.

First, the beam reinforcing bars AI, A, the outer beam reinforcing bars BI, B,
The intersection point (
After ζ-tying and restraining the pieces (shiguchi) to the wires, they are lifted up by a lifting device such as a crane, and temporarily placed on the slab S with a slight distance from each other while adjusting the position with respect to the column reinforcement. As shown in Fig. 1, beam reinforcing bars A and outer beam reinforcing bars B are dropped into slab S in advance.
(Formwork) Sl is formed, and this rli Sl
Corresponding to this, the frame is temporarily placed on the groove S1 by placing each beam reinforcing bar A and B on the flap angle 15 that has been passed. At this time, the main reinforcements 7 that are joined to each other and the joints of the main reinforcements 7 and the U-shaped main reinforcements are butted against each other.

Next, the beam reinforcing bars A1 and B are joined by pressure welding in the following procedure.

■Joining each beam reinforcing bar A1, Δ,, B1, B ■First, untie the joint 11 of beam reinforcing bar A with a suspension not shown, and connect the main reinforcement 7 of beam reinforcing bar A1 and beam reinforcing bar A. After adjusting the mutual joint surfaces, the flap angle that supports the beam reinforcement AI! Remove 5.

■With reinforcing beam A fixed, press the main reinforcing bars 7 of reinforcing beam A to the main reinforcing bars 7 on the side of beam reinforcing bars A, which abut them, and sub-beam reinforcing bars A1, A! The main reinforcements 7 of are joined together. When performing pressure welding in the X direction in this way, the edges of the reinforcing bar structure IA in the X direction are cut and floated so that they do not interfere with the reinforcing bar structure IA in the Y direction. This is why the reinforcement structure IA in the Y direction does not move. At this time, the reinforcing bar structure IA extending in the Y direction on the beam reinforcing bar AI side does not move together with the reinforcing bar structure IA extending in the X direction to which it is pressed. Here, secondary beam reinforcing bars A,,A
The joint J of each main reinforcing bar 7 of t is set to have the same length g at its outer end than the reinforcing bar structure IA, so it is located approximately in the center between the joints 11 configured as a span.

■Next, untie the joints 16 where the reinforcing bars IA of the outer beam reinforcing bars B, B, and B intersect, and create the U-shaped main bars of the outer beam reinforcing bars B1, B, and B. 4 and the corresponding beam reinforcing bar A
3. Join the joint surface of At with the main reinforcement 7 by pressure welding. At this time, the joints J6 and J3 are also connected to the joint 11 which becomes the span.
The position is shifted approximately to the center between the gates 16 and 16.

Therefore, the load in the longitudinal direction on the main reinforcements 7 and the 0-shaped main reinforcements 14 is almost eliminated, and the strength of the beam becomes constant and large. In addition, the strength against tensile stress due to load is increased, and the beam strength is maintained over a long period of time without causing defects in each joint J3, J3, J.

In addition, the 0-shaped main reinforcement 14 of the outer peripheral side beam reinforcement B on the right side in Fig. 9
By setting the above-mentioned shrinkage allowance Q1, the joined body of each beam reinforcing steel A1, A1, B8, B is constructed so that its entire length matches the intended dimension (111 yen).

After the above pressure welding is completed, each beam reinforcing bar A is
1, A7, B1, and B are dropped into the groove S, and then concrete is poured into the groove S1 to construct the beam.

[Effects of the Invention] As explained above, according to the method for pre-assembling beam reinforcing bars of the present invention, when the main reinforcements are welded to each other, the joined portion is placed approximately in the center between the spans, so that the joined The unbalanced load in the longitudinal direction of the main reinforcement is almost eliminated, and the strength of the beam is constant and large.

In addition, the strength against tensile stress due to loads is increased, and joint defects are less likely to occur, and the beam strength is maintained over a long period of time. Furthermore, by setting at least one of the main reinforcing bars to a length that includes a shrinkage margin that occurs during pressure welding, the length of the main reinforcing bars to be joined can be constructed to match the intended dimension.

[Brief explanation of the drawing]

FIGS. 1 to 9 are diagrams showing an embodiment of the present invention,
Fig. 1 is a perspective view of beam reinforcing bars set on a slab, Figs. Fig. 3 is a front view when the main reinforcements are arranged on the main reinforcement support stand, Fig. 4 is a partial perspective view of the main reinforcement support stand, and Fig. 5 is a front view when the main reinforcement is arranged using the main reinforcement support stand. Figure 6 is a front view of the aligned state, Figure 6 is a perspective view of the same, Figure 7 is a front view showing the tied state of the joint, Figure 8 is a side view of the previously assembled beam reinforcing bars, and Figure 9 is a pressure welding of the main bars together. It is a schematic side view explaining the procedure of joining. 7... Main reinforcement, 14... U-shaped main reinforcement, A.
...Beam reinforcing bars, IΔ...14 reinforcing bars,
B...Outer beam reinforcing bars, Jl, J7, J3...
...joint.

Claims (1)

[Claims] When joining a plurality of main reinforcements to each other by pressure welding and pre-assembling beam reinforcing bars with reinforcing bars incorporated therein, when joining each of the main reinforcements by pressure welding, the joint is placed approximately in the center between the spans, and each A method for pre-assembling beam reinforcing bars, characterized in that at least one of the main reinforcing bars is set to a length that provides an allowance for shrinkage that occurs during pressure welding.