JPS6261749B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of knitting a reinforcing bar cage for a concrete column body having prestressed PC steel wires for tensioning and reinforcing bars for non-tensioning. The PC steel wire is buried in the concrete column under tension to introduce prestress into the concrete column and increase the cracking resistance of the column. On the other hand, non-tension reinforcing bars are embedded within the column in order to improve the bending resistance and fracture strength of the column.

Conventionally, in order to form a reinforcing bar cage by combining tensioning PC steel wire and non-tensioning reinforcing bars, the non-tensioning reinforcing bars were first welded or tied to ring reinforcements, etc., and then spiral reinforcements were added manually. The reinforcing bar cage is formed by winding the reinforcing bar cage, end plates are provided at both ends of the reinforcing bar cage, a PC steel wire is provided by inserting the end plates, and the end plate is pulled in the opposite direction to form the reinforcing bar cage. was organizing.
However, in this conventional method, a large amount of labor was required because hand-weaving was added to the production of reinforcing bars, and the work efficiency was extremely poor in the production of concrete columns.

The present invention eliminates the drawbacks of the prior art as described above,
The purpose of the present invention is to provide a method for organizing reinforcing bar cages for concrete columns that improves work efficiency in the process of manufacturing concrete columns. In the present invention, without forming a conventional reinforcing bar, a PC steel wire having a predetermined length and a reinforcing bar longer than the PC steel wire are placed inside a helical bar braided by an automatic braiding machine. are inserted through the helical bar cage and respectively locked to end plates disposed near both ends of the helical bar cage to form a reinforcing bar cage, and the both end plates are pulled in opposite directions to knit the reinforcing bar cage. In this case, organizing the reinforcing bar cage means tensioning at least the PC steel wire to a predetermined tensile state among the helical bar cage, PC steel wire, and reinforcing bars that constitute the reinforcing bar cage, and the reinforcing bars are the aforementioned PC steel wires. When it is tensed to a predetermined tension state, it becomes a substantially straight state. Further, a tensile force may be applied to the reinforcing bar within the allowable limit force, but no tensile force is applied to the helical bar cage.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. 1 to 4 are process diagrams illustrating the steps of the method of the present invention. As shown in FIG.
A PC steel wire 2 and reinforcing bars 3 having the same characteristics are prepared, and a helical bar cage 4, which is constructed by welding spiral bars to vertical bars, is placed on an assembly table 6 using an automatic braiding machine. There are end plates 5, 5 near both ends of the
Place. In this case, the length of the PC steel wire 2 is shorter than the length of the concrete column to be manufactured,
It is tensioned and stretched to the length of the concrete column to a length that can introduce the desired prestress into the concrete column. On the other hand, the length of the non-tension reinforcing bars 3 is approximately the same as the length of the concrete column to be manufactured. An appropriate number of PC steel wires and reinforcing bars to be used shall be placed around the circumference in consideration of the diameter of the concrete column, the required strength, etc.

As shown in FIG. 2, the PC steel wire and reinforcing bars are inserted from one end plate (in this example, the left end plate) through the through hole drilled in the end plate, and then inserted into the helical bar cage 4. Insert it in an unrestricted state, then insert it through the through hole of the other end plate, and form a rivet head 1' at the tip of the PC steel wire and reinforcing bar protruding from the other end plate with an upsetter 7. . Therefore, the PC steel wire 2 and the reinforcing bars 3 are bridged between the pair of end plates 5, 5, and together with the helical bar cage 4 constitute the reinforcing bar cage 10.
Incidentally, since the distance between the pair of end plates 5, 5 placed on the assembly table 6 is approximately equal to the length of the PC steel wire 2, the PC steel wire 2 is connected to the end plates 5, 5 in a substantially straight state. It is interposed between 5 and 5. On the other hand, since the reinforcing bars 3 are longer than the distance between the end plates on the assembly table 6, they are interposed between the end plates 5 in a suspended state.

Next, the reinforcing bar cage 10 configured as described above is placed in a third
It is placed in a formwork 11 as shown in the figure. in this case,
One end plate 5 is fixed to the anchor plate 12 by a hanging bolt 13, and the other end plate 5 is slidably positioned within the formwork 11. Then, the tension plate 1 is attached to the other end plate 5 by a hanging bolt 13.
Fix 4. The tension plate 14 has a notch 14a carved therein.

Then, a desired tensioning means (not shown) such as a hydraulic jack is connected to the tension plate 14 and the tension plate 14 is pulled rightward to apply tension to the PC steel wire. After pulling the tension plate 14 to a desired length (in the illustrated example, the length at which the end plate 5 reaches the end of the formwork 11), the settling 1
5 is fitted into the notch 14a of the tension plate 14 to hold the PC steel wire 2 under tension.
At this time, the reinforcing bars 3 are set in a straight line, but some tensile force may be applied within the permissible limits. Thus, the tensioning of the reinforcing bar cage is completed, and then the mixed concrete is filled into the formwork, centrifugally compacted, and then subjected to a curing process to produce a concrete column.

As described above, according to the method of the present invention, there is no need to braid the reinforcing bar cage as in the conventional method, and the reinforcing bar cage can be constructed by inserting the PC steel wire and the reinforcing bars into the helical bar cage in an unrestricted state. Since the reinforcing bar cage is formed by simultaneously pulling the PC steel wire and reinforcing bars, work efficiency is significantly improved. In addition, in the method of the present invention, as the PC steel wire and reinforcing bars are brought into tension, they are automatically aligned with the end plate and helical bar cage, so the arrangement relationship of each member is the same. This contributes to improving the strength of the column. Furthermore, compared to the case of using conventional reinforcing bar cages, in the method of the present invention, the reinforcing bars are also firmly connected to the end plates via the rivet heads, so the strength at both ends of the column is improved. Ori,
Even when connecting piles, there is no need to weld reinforcing bars to the end plates, and sufficient strength of the joint can be ensured.

[Brief explanation of the drawing]

Figures 1 to 4 are process diagrams illustrating one embodiment of the method of the present invention, and Figure 5 is an explanation showing the arrangement of the PC steel wire and reinforcing bars when viewed in the XX direction of Figure 4. It is a diagram. Explanation of the symbols of the main parts, 2: PC steel wire, 3: Reinforcement bar, 4: Spiral bar cage, 5: End plate, 10: Rebar cage, 11: Formwork.

Claims (1)

[Claims] 1 A prestressed steel wire having a predetermined length and a reinforcing bar longer than the prestressed steel wire are inserted into the helical bar cage, and each of the reinforcing bars is fixed to the end plate arranged near both ends of the helical bar cage. The PC steel wire is suspended between the plates and is in a substantially straight state to form a reinforcing bar cage, and then the reinforcing bar cage is placed in a formwork and the both end plates are pulled in opposite directions until the reinforcing bars are in a substantially straight state. and said PC
A method for organizing a reinforcing bar cage for a concrete column body, which is characterized by keeping steel wires under tension.