JPH02178457A - Precast concrete, manufacture thereof and formwork for precast concrete - Google Patents

Abstract

PURPOSE:To arrange reinforcing bars at the correct position in the correct attitude by making the taper sections of positioning members couplable and releasable from taper holes provided on both end plates of a formwork and screwing screw reinforcing bars into them. CONSTITUTION:Taper holes 15b are provided on both end plates 12 and 12 of a precast concrete formwork 10 at positions where screw reinforcing bars 3 are inserted, and the taper sections 13b of positioning members 13 and 13 are arranged couplably or releasably. The screw reinforcing bars 3 are screwed into the positioning members 13 and 13 and arranged primarily at the correct position of the formwork 10 in the correct attitude. When multiple precast concrete blocks to be connected are manufactured, formworks are connected together in advance, then concrete is placed, thereby smooth connection is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to precast concrete, a method for producing the same, and a formwork used in its production.

[Prior Art] In recent years, when constructing a reinforced concrete structure, a large number of precast concrete members of predetermined dimensions are manufactured in advance at a factory, and these members are sequentially connected and assembled at the construction site. Many methods have been adopted due to the demand for shorter construction times.

Conventional precast concrete has a structure in which a plurality of simple, generally cylindrical reinforcing bars are buried inside, and the ends of each reinforcing bar protrude from the concrete part.

When connecting the above-mentioned conventional precast concrete, the ends of corresponding reinforcing bars in the two precast concretes to be connected are connected via a reinforcing bar connecting joint. This joint for connecting reinforcing bars has a cylindrical shape,
The inner diameter of the through hole provided along the axis is larger than the outer diameter of the reinforcing bar. The ends of the reinforcing bars to be connected are inserted from both sides into the through-holes of this joint for connecting reinforcing bars, and the inside thereof is filled with mortar and hardened to connect the reinforcing bars. Thereafter, the entire joint between the two precast concretes is surrounded by a formwork, and the inside of the mold is filled with mortar to connect the two precast concretes.

[Problem to be Solved by the Invention 1] However, in the conventional precast concrete mentioned above, the positions of the reinforcing bars are very inaccurate, and the outer circumferential surface of the reinforcing bars is covered with paris produced during forging. In order to cover these protrusions, the inner diameter of the through hole of the joint for connecting reinforcing bars had to be made considerably large, and therefore the joint itself had to be large. However, when the joint for connecting reinforcing bars is made large in this way, a problem arises in that when the reinforcing bars are connected and then connected with concrete on the outside, it may not be possible to ensure a sufficient cover thickness of concrete.

This invention was made in view of the above-mentioned problems of the conventional technology, and its purpose is to provide precast concrete with threaded reinforcing bars and to accurately place threaded reinforcing bars when manufacturing this precast concrete. It is an object of the present invention to provide a formwork that allows reinforcement to be placed at certain positions, and a method for manufacturing precast concrete that can be used by easily connecting a plurality of them in a straight line.

[Means for solving the problem 1 This invention has been made to achieve the above object,
The gist of the first invention is that in precast concrete in which a plurality of reinforcing bars are embedded inside the concrete in a penetrating manner along its longitudinal direction, the reinforcing bars have screw threads formed with spiral convex portions on the outer peripheral surface thereof. Precast concrete is characterized by the use of reinforcing steel.

Further, the gist of the second invention is that the hollow portion has a hollow portion into which concrete is poured, and both ends in the direction of the technique are closed by end plates to form a box shape, and each end plate has a hollow portion that is hung between the two end plates. Each end of the reinforcing bars to be passed can be supported in a penetrating state,
In a precast concrete formwork for manufacturing precast concrete by pouring concrete with reinforcing bars stretched between both end plates, the reinforcing bars spanned between both end plates have a spiral convex portion on the outer peripheral surface. The formed threaded reinforcing bar is used, and each end plate is provided with a tapered hole that has a diameter larger than the circumscribed circle of the threaded reinforcing bar and gradually decreases in diameter toward the cavity, and each tapered hole has a diameter larger than the circumscribed circle of the threaded reinforcing bar. A positioning member is engageable and detachable from the positioning member, and a tapered portion is formed at the tip of the positioning member, the diameter of which gradually decreases toward the tip at approximately the same taper angle as the tapered hole, A formwork for precast concrete, characterized in that a through hole is provided in the center along the axis of the positioning member, the inner circumferential surface of which is formed with a spiral groove that screws into the spiral convex portion of the threaded reinforcing bar. It is in.

Furthermore, the main feature of the third invention is to provide a reinforcing bar connecting joint having a helical groove in which the helical protrusion of the threaded reinforcing bar according to the first claim is threadedly engaged with the inner circumferential surface of the short cylindrical main body. In the method for manufacturing precast concrete according to the above $1 claim, in which a plurality of precast concrete forms are connected along the longitudinal direction, a plurality of formworks according to the above second claim are prepared and arranged in a line along the longitudinal direction, and each The above-mentioned spun reinforcing bars are inserted into the opposing tapered holes of both end plates of the formwork, and the positioning member according to the second claim is screwed to the end of each spun reinforcing bar protruding from the end plates, and further, the positioning members according to the second claim are screwed together, and the positioning members according to the second claim are screwed together. Both threaded reinforcing bars attached to the formwork and arranged in a substantially straight line are connected via the reinforcing bar connection joints, and then each positioning member is tightened to connect the tapered portion of each positioning member to each end plate of the formwork. Connect multiple formworks by tightly engaging each of the taper holes in the formwork, and while maintaining this state, concrete is poured into the cavity of each formwork and cured, and after curing, the formworks are connected. The present invention provides a method for manufacturing precast concrete, characterized in that the joint for connecting reinforcing bars, which had been previously used, is removed, and each formwork is also removed.

[Action 1] Insert threaded reinforcing bars into opposing tapered holes in both end plates of the formwork, screw positioning members onto each end of the threaded reinforcing bars protruding from the end plates, and tighten them to secure each positioning member. The tapered portion is tightly engaged with the tapered hole of each end plate. By doing so, if the tapered holes are formed in the end plates at accurate positions, each threaded reinforcing bar can be uniquely arranged in the formwork at an accurate position and in a correct posture.

That is, by using this formwork, it is possible to obtain precast concrete in which sprung reinforcing bars are attached in extremely accurate positions and in the correct orientation.

In addition, when manufacturing the above-mentioned precast concrete in which multiple pieces of precast concrete are connected along the longitudinal direction, the formworks are connected in advance before pouring concrete into each formwork. When connecting precast concrete manufactured by pouring concrete, if you connect it in the order of temporary assembly at the time of manufacturing as described above, the pitch of the spiral protrusions of the threaded reinforcing bars to be connected may not match. Precast concrete can be smoothly connected to each other without any problems and without any trouble.

In each precast concrete, the threaded reinforcing bars are placed in the correct position and in the correct posture, so it is necessary to make the joints for connecting the reinforcing bars to the minimum necessary size. A sufficient concrete cover thickness can be obtained.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described based on the drawings from FIG. 1 to FIG. 10.

Figures 1 and 2 are precast concrete 1
It shows a front view and a right side view.

This precast concrete 1 is composed of a square columnar concrete part 2 and 16 threaded reinforcing bars 3 embedded in the concrete part 2 in a penetrating state.

The threaded reinforcing bar 3 has a rod shape, and has a spiral convex portion 3 on its outer peripheral surface.
g (see FIG. 6 for details) is formed.

The threaded reinforcing bars 3 are precisely arranged at equal intervals on the periphery of the concrete part 2 and along its longitudinal axis.

FIGS. 3 to 6 show a precast concrete formwork 10 used when manufacturing the precast concrete 1 described above. This formwork 10 includes a frame body 11 having a U-shape in longitudinal section and closing three sides along the longitudinal direction, and end plates 12 fixed to both ends of the frame body 11 via bolts and nuts (not shown). .12 and a positioning member 13 for the screw reinforcing bars 3.The interior surrounded by the frame body 11 and both end plates 12 and 12 is a cavity 14 into which concrete is poured, and the upper part thereof is open. There is.

In each end plate 12, 16 through holes 15 whose axes are positioned exactly perpendicular to the end plate 12 are provided at exactly equal intervals in a portion corresponding to the peripheral edge of the cavity 14. . The axes of the through holes 15 facing each other in the end plates 12 are located on a straight line and parallel to the axis of the cavity 14. As shown in FIG. 6, this through hole 15 is a straight hole 15a with a diameter slightly larger than the outer diameter of the threaded reinforcing bar 3 at the part that connects to the cavity 14, and the part outside this straight hole 15a is a straight hole 15a. The diameter of the straight hole 15a gradually decreases toward the straight hole 15a to form a tapered hole 15b.

The positioning member 13 can be engaged with and detached from the tapered hole 15b. As shown in FIG. 6, the positioning member 13 has an engaging portion 1 for a tool such as a pipe wrench on the base side.
3a, its cross-sectional shape is hexagonal like a nut, and the tip side is a taper part 13b, the taper angle of which is approximately the same angle as the taper angle of the taper hole 15b. is being used. Moreover, this positioning member 1
A through hole 13c is provided in the center of 3 along its axis. A helical groove is formed on the inner circumferential surface of the through hole 13c to be screwed into the helical protrusion 3a of the threaded reinforcing bar 3.

Precast concrete 1 is manufactured by using the above-mentioned formwork 10 for precast concrete as follows.

First, the end plates 12.12 are attached to both ends of the frame body 11 to assemble a box with an open top.Next, a pair of through holes 15.1 are installed facing each other in both end plates 12.12.
A threaded reinforcing bar 3 is inserted through the threaded reinforcing bar 5, and both ends of each threaded reinforcing bar 3 are made to protrude outward from each end plate 12. And each end plate 12
The positioning members 13 are screwed onto both ends of the threaded reinforcing bar 3 protruding from the screws with their tapered portions 13b directed toward the hollow portion 14, and the tapered portions 13b of each positioning member 13 are engaged with the tapered holes ISb of the end plate 12. Bring it into close contact. By doing this, each threaded reinforcing bar 3 is placed at the desired correct position,
The axis thereof will be parallel to the axis of the cavity 14, and the end of each threaded reinforcing bar 3 will be arranged to be orthogonal to each end plate 12.

Concrete is poured into the cavity 14 of the formwork 10 to which the 16 threaded reinforcing bars 3 have been attached as described above, and after a predetermined curing period, positioning members 1 are placed from each threaded reinforcing bar 3.
3, each end plate 12, 12 is removed, and the frame body 11 is released from the mold, thereby completing the precast concrete 1 shown in FIGS. 1 and 2. In the precast concrete 1 manufactured in this way, the screw reinforcing bars 3 are arranged at the correct positions as described above, and the ends thereof protrude vertically from the end face of the concrete part 2.

Next, when constructing a tall column by connecting multiple pieces of precast concrete 1 along its longitudinal direction,
Precast concrete 1 used for this is manufactured as follows.

In advance, prepare the above-mentioned precast concrete formwork 10 in the number necessary for the column to be constructed, assemble the frame body 11 and both end plates 12 and 12 respectively, insert the screw reinforcing bars 3 into each through hole 15, and A positioning member 13 is provided at each portion.
Screw them together.

However, at this point, for one formwork 10, each threaded reinforcing bar 3 is fixed by tightly engaging the tapered part 13b of the positioning member 13 with the tapered hole 15b of each end plate 12 as described above. However, for the other formwork 10, each spun reinforcing bar 3 is inserted, but each positioning member 13 is only loosely screwed together.
b is not tightly engaged with the tapered hole 15b of each end plate 12.

Using the above-mentioned two formworks 10 as a reference, the pond formwork 10 is connected to this formwork 10, and the pond formwork 10 is further connected to this connected formwork lO, and so on. We will connect them.

\For example, the formwork 10 located on the leftmost side in Fig. 7
If is the above-mentioned standard formwork, then the pond formwork 10 is aligned on a straight line to the right of it. Then, the formwork 1 that serves as the above standard
The reinforcing bar connecting joint 20 is screwed sufficiently deep into each spun reinforcing bar 3 protruding from the right side end plate 12 of 0. This reinforcing bar connection joint 20 has a cylindrical shape, and has a spiral groove (not shown) formed on its inner circumferential surface to threadably engage with the spiral convex portion 3a of the threaded reinforcing bar 3.

Next, each reinforcing bar connection joint 20 is screwed to the end of each threaded reinforcing bar 3 protruding from the left end plate 12 in the pond formwork 10 that is lined up immediately to the right of the reference formwork 10, These two formworks are screwed in by the required length 10.
10 corresponding threaded reinforcing bars 3 are connected. Thereafter, each positioning member 13 screwed onto both ends of each threaded reinforcing bar 3 of the pond formwork 10 is tightened, and the tapered portion 13b is tightly engaged with each tapered hole 15bi of each end plate 12. By doing so, each threaded reinforcing bar 3 of the other formwork 10 is fixed.

By sequentially repeating the above steps, as shown in FIG. 7, the threaded reinforcing bars 3 are fixed to all the prepared formworks 10, and the threaded reinforcing bars 3, 3, etc. of the adjacent formworks 10 are fixed.
- are connected via the reinforcing bar connection joint 20, and as a result, each formwork 10 is connected.

Next, concrete is placed in the cavity 14 of each formwork 10 and cured for a predetermined period of time.

After the above-mentioned curing, the reinforcing bar connecting joints 20 are removed from each threaded reinforcing bar 3, and the formworks 10 are separated from each other.

After separating each formwork 10, each formwork 10 is separated by the same procedure as described above.
By releasing from the mold, precast concrete 1 necessary for constructing columns can be obtained.

When constructing columns at a construction site, if the above-mentioned connection order at the time of manufacturing is reproduced, the M7' of the threaded reinforcing bars 3 to be connected and the pitch of the spiral convex portions 3a will match correctly. As shown in FIG. 8, the precast concrete 1 can be connected smoothly with the reinforcing bar connection joint 20 without any trouble.

The entire connecting part A of each precast concrete 1 connected via the reinforcing bar connecting joint 20 is surrounded by a wooden frame 30 as shown in FIG. When the pillar 40 is removed, the pillar 40 as shown in Fig.
is completed.

Incidentally, in each precast concrete 1, the threaded reinforcing bars 3 are arranged in the correct position and in the correct posture, so the reinforcing bar connecting joint 20 that connects them should be made to the minimum necessary size. , a sufficient thickness of concrete can be ensured at the connecting part A.

This invention is not limited to the above-described embodiments, and various embodiments can be adopted.

For example, it goes without saying that the reinforcing bars may be arranged so as to be wound around the threaded reinforcing bars 3 in the above embodiment.

Further, in the above embodiment, the precast concrete 1 was used to construct the columns, but it goes without saying that it may also be used to construct beams.

L Effects of the Invention j As explained above, this invention has the excellent effects described below.

That is, a tapered hole is provided in both end plates of the precast concrete formwork at the part where the reinforcing bar is passed through once, and the tapered part of the positioning member for the threaded reinforcing bar can be engaged and disengaged from this tapered hole. Furthermore, since the threaded reinforcing bar is screwed into this positioning member, an excellent effect is achieved in that the threaded reinforcing bar can be uniquely placed in the formwork at the correct position and in the correct posture. be done.

Therefore, the precast concrete manufactured using the above-mentioned precast concrete formwork has the excellent effect that threaded reinforcing bars are arranged at accurate positions and in correct postures.

In addition, when manufacturing the above-mentioned precast concrete in which multiple pieces of precast concrete are connected along the longitudinal direction, the precast concrete formworks are connected in advance before pouring the concrete, so that after pouring the concrete, When connecting the manufactured precast concrete, if the precast concrete is connected in the order of the vi combinations described above, an excellent effect can be obtained in that the precast concrete can be connected smoothly without any trouble.

Furthermore, there is also the effect that a sufficient cover thickness of concrete can be secured at the connecting portion.

[Brief explanation of the drawing]

The drawings from Fig. 1 to Fig. 10 show one embodiment of the present invention. Fig. 1 is a front view of precast concrete, Fig. 2 is a right side view of the same, and Fig. 3 is a mold for precast concrete. The front view of the frame, Figure 4 is the same right side view, Figure 5 is the front view of the frame.
The figure is the same plan view, Figure 6 is an enlarged cross-sectional view taken along arrows Vl-Vl in Figure 4, Figure 7 is a front view showing the state in which precast concrete formwork is connected in a straight line, and Figures 8 to 10. These are front views showing each construction process when constructing columns using this precast concrete. 1... Precast concrete, 2... Concrete part, 3... Screw reinforcing bar, 3a
...Spiral convex portion, 10...Formwork for precast concrete, 12...
- End plate, 13... Positioning member, 13b... Tapered part, 14... Cavity part, 15b... Tapered hole, 20... Joint for connecting reinforcing bars.

Claims (3)

[Claims] (1) In precast concrete in which multiple reinforcing bars are embedded inside the concrete in a penetrating manner along its longitudinal direction, the reinforcing bars are threaded reinforcing bars with spiral protrusions formed on the outer peripheral surface. Precast concrete characterized by: (2) It has a hollow part into which concrete is poured, and both longitudinal ends are closed by end plates to form a box shape, and each end plate has each end of the reinforcing bar stretched between the two end plates. In a precast concrete formwork that can be supported in a penetrating state and is used to produce precast concrete by pouring concrete with reinforcing bars stretched between both end plates, the reinforcing bars spanned between the two end plates. A threaded reinforcing bar with a spiral convex portion formed on the outer circumferential surface is used.
Each end plate is provided with a tapered hole that has a diameter larger than the circumscribed circle of the threaded reinforcing bar and gradually decreases in diameter toward the cavity, and a positioning member for the threaded reinforcing bar can be engaged with and disengaged from each tapered hole. At the tip of this positioning member, there is formed a tapered part whose diameter gradually decreases toward the tip at approximately the same taper angle as the taper hole, and at the center along the axis of the positioning member. A formwork for precast concrete, characterized in that a through hole is provided on an inner circumferential surface in which a spiral groove is formed to engage with a spiral convex portion of the threaded reinforcing bar. (3) A plurality of reinforcing bars are connected to the inner circumferential surface of the short cylindrical main body along its longitudinal direction via a reinforcing bar connecting joint having a helical groove into which the helical convex portion of the threaded reinforcing bar according to the first aspect is screwed. In the method for manufacturing connected precast concrete according to the first claim, a plurality of formworks according to the second claim are prepared and arranged in a line along the longitudinal direction, and both end plates of each formwork are opposed to each other. Insert the above threaded reinforcing bar into the tapered hole,
The positioning member according to the second claim is screwed onto the end of each threaded reinforcing bar protruding from the end plate, and both threaded reinforcing bars attached to mutually adjacent formworks and arranged substantially in a straight line are used to connect the reinforcing bars. A plurality of formworks are connected via a joint, and then each of the positioning members is tightened to tightly engage the tapered portion of each positioning member with each tapered hole of each end plate of the formwork. , While maintaining this state, concrete was poured into the hollow part of each formwork and cured, and after curing, the above-mentioned reinforcing bar connection joints that connected each formwork were removed, and each formwork was also removed. A method for producing precast concrete characterized by: