JPH0243859B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] When constructing a cylindrical reinforced concrete structure using the sliding formwork method, the present invention uses a large reinforcing bar net or large steel plate, etc., made of pre-assembled reinforcing bars, as a wall body. This invention relates to a sliding formwork device using a long-legged yoke that enables concrete pouring of a wall body while being assembled integrally along the wall.

[Conventional technology]

The yoke used in the conventional sliding formwork method has outer and inner steel legs facing each other, and a beam is spanned over the top of both legs to form a U-shape.A climbing jack is attached to the top of the yoke. Formwork is provided on the inside facing each other at the bottom of both the outside and outside legs,
The jacks are raised along the foundation and the previously cast concrete wall by the operation of the jacks, and the concrete poured between the inner and outer formworks is raised in a direction perpendicular to the formwork while it is still uncured. The height of the yoke and the strength of the members of the inner and outer legs are determined so that the distance between the inner and outer formwork is expanded by the applied force, that is, the concrete lateral pressure, within a certain tolerance range.

[Problem that the invention seeks to solve]

Therefore, the greater the height from the lower end of the yoke beam to the upper end of the formwork, that is, the height to the upper end of the slide work stage (referred to as yoke inseam height), the higher the height will be when assembling transverse reinforcing bars buried in the wall or constructing an airtight silo. It is easier to insert steel plates and other members for airtightness, but as the yoke inseam height increases, even if the concrete side pressure is the same, the bending stress applied to the yoke becomes greater than when the yoke height is small. In order to maintain a constant spacing between the formworks, it is necessary to make the cross-sectional shape of the yoke legs larger, which increases the weight of the yoke, making assembly and disassembly of the yoke time-consuming and uneconomical. This will cause problems with slide work as well. For this reason, the yoke inseam height is restricted to approximately 50 cm or less, and because the yoke inseam height is small, workers must bend down to perform assembly work that involves penetrating the yoke inseam of the horizontal reinforcing bar. figure,
The work becomes difficult and inefficient. This is because the horizontal reinforcing bar assembly work is also limited to the range of the yoke inseam height.

If this restriction on the yoke inseam height can be removed and the yoke inseam height can be increased without increasing the cross-sectional shape of the yoke legs, it will be easier to assemble horizontal reinforcing bars, allowing large rebar nets or steel plates to pass through the yoke inseam. As a result, the work of assembling the reinforcing bars of the wall can be greatly reduced, and the construction of reinforced concrete walls with steel plates inside can be easily carried out.

[Means for solving problems]

The present invention has been made in view of this, and is used in the sliding formwork construction method for constructing cylindrical reinforced concrete walls (silos) between adjacent outer legs of yokes arranged at predetermined intervals along the circumference of the wall. A horizontal polygonal annular beam connecting the yokes in a straight line is provided within the range of the yoke's inseam height, and a radial beam is provided that connects the heads of the opposing yokes across the center of the cylindrical wall plane. Therefore, in addition to reinforcing the outer legs of the yoke, it is necessary to install a radial beam at a height below the upper end of the formwork for the inner legs of the yoke, or to form an annular beam parallel to the inside of the cylindrical wall and in close contact with the inner legs of the yoke. By reinforcing the inner legs by providing them at the height of the upper end of the frame, the crotch height of the yoke can be increased without increasing the cross-sectional shape of the yoke.

〔Example〕

The present invention will be explained below based on illustrated embodiments. Fig. 1 is a sectional view showing an embodiment of a sliding formwork device using a long leg yoke of the present invention, Fig. 2 is a plan view thereof, and Fig. 3 is a developed view seen from the side. Reference numeral 1 denotes a yoke that is arranged at arbitrary intervals in the circumferential direction of a wall when constructing a cylindrical reinforced concrete structure. Beam 1c at the top
A climbing jack 2 is fixed to the upper part of the yoke 1, and a formwork 3 is installed inside the lower part of the inner and outer legs of the yoke.
a and 3b are provided, respectively. The formworks 3a and 3b are double-arranged inside and outside to support the concrete and to maintain the thickness of the wall until the concrete wall becomes self-supporting. It is fixed to . Also 4
The yoke 1 is a jack rod that can be added to and established on the foundation or in the poured concrete wall, and serves as a reaction force support for the climbing jack, and the yoke 1 is raised along this rod by climbing on the jack. be. 5 is a sliding work floor placed on the formwork 1a,
When the jack operates and rises along the rod,
The formworks 1a, 1b and the work floor 5 are made to rise together with the horizontal axis. In addition, the yoke's inseam height is larger than that of conventionally used yokes.
An annular beam 6 is provided to connect the outer legs of adjacent yokes at a required height, for example, several tens of centimeters, from the work floor 5 in order to reinforce the yokes. Since this connects the yokes arranged at arbitrary intervals along the circumferential direction of the cylindrical concrete wall, it has a polygonal shape when viewed from above, and the lateral pressure P1 of the concrete placed between the formworks 3c and 3b is The force applied to the outer leg of the yoke is supported by the binding force R of the annular beam 6. Also, the force P3 acting on the upper part of this yoke outer leg
An upper radial beam 7 is provided so as to connect the heads of the opposing yokes to support the yokes, and the synergistic action of the upper radial beam 7 and the annular beam 6 reinforces the outer legs of the yoke. Reference numeral 8 denotes a lower radial beam for reinforcing the yoke inner legs 1a, which is also constructed between the inner legs 1a of the opposing yokes, but is generally supported below the work floor 5, and is supported by both the upper and lower radial beams. Each height of the beam also serves to support the work floor 5. As shown in FIG. 3, there are also straight beams 9 between the heads of the yokes arranged along the circumferential direction of the wall.
Places 10 and 1 that cross each other in a plane surrounded by the outer leg 1b of the yoke and the upper and lower beams 6 and 9 are constructed.
0 is provided, and the inclination of the yoke may be prevented by adjusting the turnbuckle 11 provided at this place. Therefore, the inner yoke leg 1a
The upper part of the surface surrounded by the work floor 5 is open, and the height of the yoke's crotch becomes high, so that large steel plates, assembled large nets, etc. can be freely passed through the yoke's crotch.

Although Figures 1 and 2 show the case of a single silo, this is also applicable to a composite structure in which a plurality of cylindrical walls 12 are assembled; however, in this case, the outer formwork 3b does not have a perfect circular shape because it bypasses the joint of the circular wall body 12, but since the annular beam 6 is provided at a position above the upper end of the formwork, it can be made into a polygonal ring shape.

[Effect]

When using a yoke with long legs constructed as described above, concrete is poured between the formworks facing the lower part of the outer legs of the yoke, and when concrete side pressure P1 (yoke structural horizontal force) is applied, If there is no annular beam 6, the maximum bending stress Mmax near the yoke beam 1c of the yoke leg will be P1 x P2 (distance from the work floor to the top of the yoke), but if the annular beam 6 is located in the middle of the outer yoke leg, Since it is installed between the outer yoke legs of adjacent yokes, the maximum bending stress M′max is
P ₁ × L1 (distance from the work floor to the circular beam),
The stress occurs at the height of the annular beam. In addition, since the head of the yoke is connected between the yokes by the upper radial beam, the stress state of the pair of yoke structural surfaces, that is, the pair of yoke structural surfaces connected by the upper radial beam, is different from that of the wall concrete at the same height. If the driving conditions are almost the same, the horizontal force exerted on the outer legs of the yoke at both ends will be the same, and therefore the reaction force P3 generated on the yoke head due to this horizontal force will also be balanced through this upper radial beam. The entire structure becomes stable.

〔Effect of the invention〕

The slide device according to the present invention can be used not only for a single cylindrical structure but also for a composite structure in which a plurality of cylindrical walls are assembled. have

(1) The legs of the yoke only need to be thin members that can withstand only the vertical force required to lift the device, so even if the yoke inseam is extended, weight and volume can be saved, making it possible to save labor and streamline slide construction. becomes.

(2) Since the yoke's inseam is large, the horizontal reinforcing bars can be assembled higher prior to lifting by jacking the equipment, reducing waiting time during slide construction.

(3) A reinforcing bar network made by assembling reinforcing bars in advance is placed along the wall by passing through the crotch of the yoke, and the adjacent reinforcing bars are joined by partially overlapping each other and buried in the wall concrete. By doing so, it is possible to carry out sliding construction work by greatly reducing the labor involved in assembling reinforcing bars.

(4) An airtight plate such as a steel plate with dimensions within the inseam height of the great yoke is placed along the wall by passing through the inseam of the yoke, and the ends of the airtight plate are joined and welded to form an integral piece. After that, it is possible to construct a steel plate concrete silo by pouring concrete walls.

[Brief explanation of drawings]

FIG. 1 is a sectional view, FIG. 2 is a plan view, and FIG. 3 is a developed view seen from the side. 1 is a yoke, 1a is an inner leg, 1b is an outer leg, 2 is a climbing jack, 3a and 3b are formworks, 4 is a jack rod, 5 is a work floor, 6 is an annular beam, 7, 8
9 is a radial beam, 9 is a straight beam, 10 is a place, 11 is a turnbuckle, and 12 is a wall.

Claims (1)

[Claims] 1. In the sliding formwork method in which a cylindrical reinforced concrete wall is constructed by pouring concrete while raising the formwork, a part of the equipment used in the method is arranged along the cylindrical wall. By providing a horizontal member that connects and goes around the middle heights of the outer legs of a plurality of yokes, and by alternately connecting and reinforcing the inner legs of the yokes below the upper end of the formwork,
A sliding formwork device using a long-legged yoke, characterized in that the length of the legs of the yoke can be extended.