JPH0373689B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a formwork mounting device used in the cantilever construction method.

[Conventional technology]

The cantilever construction method installs a formwork mounting device on top of the existing concrete girder and places the formwork on the formwork mounting device when it is not possible to construct shoring from below in places where the girder is high or at sea. Place concrete and
This is a construction method in which girders are successively poured in front of the existing concrete girder.

FIG. 5 shows a side view of a conventional formwork mounting device.

Conventional formwork mounting equipment uses existing concrete girders
It consists of a pedestal a placed on K' and an arm b formed to project forward of pedestal a, and pedestal a is placed near the end of the existing concrete girder K', while the A formwork mounting table c with one end fixed to the lower surface of the end is extended horizontally, and the free end of the formwork mounting table c is suspended by an arm b.

Then, the formwork is assembled on the formwork mounting table c, concrete is poured, and the existing concrete girders K' are sequentially poured.

When using the formwork mounting device, the weight of the concrete acts as an upward lifting force behind the pedestal a.
Using steel materials etc., mount a is installed on the existing concrete girder.
It is necessary to fix it to K′ and take measures to prevent it from falling.

[Problems to be solved by the present invention]

Conventional formwork mounting devices have the following problems.

(b) Because there is a cross member e in the transverse direction of the existing concrete girder K', which serves as a passageway for carrying various materials,
It becomes difficult to bring in various materials, resulting in poor work efficiency.

(b) As shown in Figure 6, if the bridge to be constructed is a cable-stayed bridge in which the tower and the bridge girder are diagonally connected by cable d, the cable d and the cross member e intersect, and the formwork mounting device movement becomes difficult.

(c) The weight of the concrete acts as an upward lifting force at the rear of the pedestal a, and instability remains in terms of stability.

[Object of the present invention]

The present invention was made to solve the above problems, and its purpose is to provide a formwork mounting device that can secure a wide working space on an existing concrete girder and has excellent stability. There is a particular thing.

[Means for solving problems]

That is, the present invention provides a rigid frame body that protrudes outward from both edges of an existing structure, the rear half of the frame being located on the lower surface of the existing structure, and the front half of the frame being located on the lower surface of the existing structure. A horizontal support frame that extends horizontally forward,
A pair of central pillars that are vertically installed at the center of both edges of the horizontal support frame and whose midpoints are hooked to an existing structure, and a plurality of connecting members that connect the top of each central pillar and both ends of the horizontal support frame. This is a formwork mounting device consisting of:

〔Example〕

Next, one embodiment of the present invention will be described with reference to the drawings.

(b) Overall configuration of formwork mounting device FIG. 1 shows an overall view of the formwork mounting device A.

The formwork mounting device A is installed on a horizontal support frame that extends horizontally forward from the lower end of the existing concrete girder K, which is an existing structure, and is installed vertically at the center of both edges of the horizontal support frame, It is composed of a pair of central pillars 2 that are hung on the horizontal support frame, and a plurality of diagonal members 3 that connect the top of each central pillar 2 and both ends of the horizontal support frame.

(b) Horizontal support frame The horizontal support frame consists of a plurality of vertical members 1 arranged along the extension direction of the existing concrete girder K, and vertical members 1
It is composed of a plurality of cross members 4 arranged in the cross direction.

The outermost vertical members 1, 1 of the vertical members 1 constituting the horizontal support frame are positioned so as to protrude outward from both edges of the existing concrete girder K in consideration of the connection of the diagonal members 3.

The rear half of the horizontal support frame is in contact with the lower surface of the existing concrete girder K, and the front half extending forward of the existing concrete girder K is used to assemble the formwork and support the weight of the concrete.

The right half of FIG. 3 shows a sectional view of the rear half of the horizontal support frame.

A lower support stand 1 is installed on the upper surface of the rear half of the horizontal support frame.
1 is provided, and each lower support stand 11 is further provided with lower wheels 12 which can run on the lower surface of the existing concrete girder K and are movable up and down via lower jacks 13.

In addition, as shown in FIGS. 2 and 3, the work scaffold 5 may be suspended below the horizontal support frame.

(c) Central pillar The central pillar 2 is a member that transmits the entire weight of the formwork mounting device A to the existing concrete girder K to support it. An upper support stand 21 is provided on the opposite side of each central pillar 2, and this The upper support stand 21 is hung on the upper surface of both ends of the existing concrete girder K.

The lower part of each central column 2 is connected to approximately the center of a horizontal support frame that projects outward from both edges of the existing concrete girder K.

The left half of Figure 3 shows the hanging structure between the central column 2 and the existing concrete girder K.

The upper support base 21 is provided with upper wheels 22 that can run on the upper surface of the existing concrete K and are movable up and down via an upper jack 23.

The lower jack 13 and the upper jack 2
The structure is such that the lifting and lowering of the entire formwork mounting device can be adjusted by the expansion and contraction operations of 3.

(d) Diagonal member If the rear part of the horizontal support frame is brought into contact with the lower surface of the existing concrete girder K and the center part of the horizontal support frame is brought into contact with the upper surface of the existing concrete girder K via the center column 2, the shape Since it becomes a propped structure, the strength of the front half of the horizontal support frame decreases.

Therefore, the upper end of the central column 2 and each end on both sides of the horizontal support frame are connected by diagonal members 3 to support and reinforce the horizontal support frame.

The diagonal members 3 are installed in the existing concrete girder K so as not to cross the space above the existing concrete girder K.
placed on both sides of the

[Effect]

Next, a method of using the formwork mounting device of the present invention will be explained.

(b) Installation of the formwork mounting device As shown in Figure 2, the formwork mounting device is held between the top and bottom surfaces of the tip of the existing concrete girder K, and the first half of the horizontal support frame is placed horizontally in front of the existing concrete girder K. Install it so that it sticks out.

The weight of the formwork mounting device is the weight of the upper wheels 2 of the central column 2 that land on the top surface of the tip of the existing concrete girder K.
2, and the landing point of the upper wheels 22 and the installation point at the rear of the horizontal support frame that abuts the rear lower surface of the existing concrete girder K prevent the formwork mounting device from falling forward.

More preferably, the cross member 4 at the center column 2 and the existing girder K are tightly connected and fixed with a steel material 6 or the like.

(b) Installation of formwork Next, use the existing concrete girder K as a passageway to transport various materials, and install the existing concrete girder K.
Formwork B is assembled on the front half of the horizontal support frame located at the lower front of the frame.

(c) Concrete pouring After completing the assembly of formwork B, pour concrete and extend the existing concrete girder K.

As shown in FIG. 4, the weight of the concrete acts as a clockwise rotational moment about the center of the horizontal support frame as a fulcrum.

This rotational force is supported and restrained by the upper support stand 21 of the central column 2 that comes into contact with the top surface of the tip of the existing concrete girder K, and the lower support stand 11 at the rear of the horizontal support frame that comes into contact with the lower surface of the rear part of the existing concrete girder K. Ru.

Therefore, even if the weight of concrete acts on the horizontal support frame projecting forward of the existing concrete girder K, the formwork mounting device will not fall.

(d) Demoulding and movement of equipment After curing the concrete, the steel material 6 shown in Figure 2
After removing the mold, the upper jack 23 is retracted and the lower jack 13 is extended to forcibly lower the entire formwork mounting device to remove the mold.

After demolding, move the formwork mounting device to the end of the existing concrete girder K that has been poured, and repeat the process described above.

[Effects of the present invention]

Since the present invention is as explained above, the following effects can be expected.

(b) Since there are no members that cross the top of the existing structure, a wide working space can be secured on the existing concrete girder, and various materials can be carried in smoothly, improving work efficiency.

(b) When applied to the construction of cable-stayed bridges, there are no members that cross the diagonal cables connecting the towers and bridge girders, so construction can be carried out smoothly, making it suitable for the construction of cable-stayed bridges.

(c) The formwork mounting device comes into contact with the upper and lower surfaces of the existing structure in a sandwiching manner, so that the rotational moment generated in the formwork mounting device can be effectively restrained.

Therefore, high stability of the formwork mounting device can be maintained.

Moreover, since the horizontal support frame protruding forward of the existing structure is supported by the central pillar via the diagonal member, the burden on the horizontal support frame can be reduced.

[Brief explanation of drawings]

Figure 1: Overall perspective view of the formwork mounting device of the present invention,
Figure 2: Explanatory diagram of how to use the mold placement device, Figure 3
Figure: A partial cross-sectional view of the central and rear parts of the formwork mounting device that comes into contact with the existing concrete girder, Figure 4: A model diagram to explain the load bearing of the formwork mounting device, Figure 5 Figure: Model diagram for explaining the load burden of the conventional formwork mounting device, No. 6: A cross-sectional view when the conventional formwork mounting device is used in a cable-stayed bridge. 1: Vertical member, 2: Central column, 3: Diagonal member, 4: Horizontal member,
11: Lower support stand, 21: Upper support stand, A: Formwork mounting device, B: Formwork, K, K': Existing concrete girder, a: Frame, b: Arm, c: Formwork mounting stand,
d: Diagonal cable.

Claims (1)

[Scope of Claims] 1. A rigid frame projecting outward from both edges of an existing structure, wherein the rear half of the frame is located on the lower surface of the existing structure, and the front half of the frame is connected to the existing structure. A horizontal support frame that extends horizontally in front of the object, a pair of central pillars that are vertically installed at the center of both edges of the horizontal support frame and that are hooked on the existing structure at the middle, and the top of each central pillar and the horizontal support. A formwork mounting device consisting of multiple connecting members that connect both ends of the frame.