JPH0489906A - Dismantling method of formwork support for arch concrete construction - Google Patents

Abstract

PURPOSE:To dismantle a formwork support safely and easily by removing a pin joining the top ends of supports for connecting a plurality of semi-arch trusses to each other, and tilting formwork supports around pins on both bottom ends thereof as axes. CONSTITUTION:An arch shaped support A is constructed by arranging a plurality of semi-arch trusses A1, A2 in the width direction and connecting them together while each pair of them is pin jointed 3 at the upper end and both bottom ends are pin jointed 2, 2 to abutments 1, 1. Arch concrete B is then placed by using the support A. Pulleys 13a, 13a, 14a, 14a are fitted to anchor bolts 12a, 12a buried in the arch concrete B and to respective semiarch trusses A1, A2. Ropes 16, 16 of winch devices 15, 15 are laid alternately on respective pulleys 13a, 13a, 14a, 14a and their ends are secured to the anchor bolts 12a, 12a. The pin 3 for joining the semi-arch trusses A1, A2 together is removed, the ropes 16, 16 are drawn out to tilt the semi-arch trusses A1, A2 around the bottom joining pins 2, 2 as axes for hanging down.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for removing arch-shaped formwork supports used in the construction of arch concrete in arch bridges and the like.

(Prior Art) When constructing a concrete structure such as an arch bridge, a major problem arises in terms of its construction, especially the formwork support facilities required for constructing the arch-shaped concrete between the piers (including the abutments).

Therefore, the present inventor developed an economical and easy-to-implement support for arch concrete formwork.
As in inventions such as No. 2-78357 and Japanese Patent Application Laid-open No. 63-22967, we have succeeded in implementing a system in which the shoring has an arch-shaped truss structure and both ends thereof are supported on the upper part of an existing bridge pier. This simplifies the shoring structure,
Materials and costs have been reduced, and construction has become more efficient.

In the shoring of these inventions, a triangular unit support element is formed by a main rod and a pair of side rods, a large number of which are connected to each other with pins at the ends of the main rod, and are connected to each other by the secondary rods at the joints of both side rods. With a connected structure, the truss structure supporting the formwork is strong and easy to assemble and dismantle, and the shape of the arch can be changed by simply changing the length of the sub-rods. Therefore, it can be repeatedly applied to the construction of concrete arches of various sizes and arch shapes, and it is possible to make wide-ranging improvements in overall construction, such as saving materials and simplifying construction. - The formwork support of the above invention has been widely adopted as its technical and economical superiority has been recognized, but as a result, recently, it has become possible to develop There have been demands for shoring for arch concrete with long spans or flat large arcs.

However, subsequent research has made it possible to resolve most of the technical problems with the arch shoring itself.

By the way, the above-mentioned shoring is to be removed after the arch concrete is placed, but the arch concrete becomes an obstacle and cannot be dismantled and removed using a crane.

Therefore, conventionally, moving wheels are provided at the lower end of the shoring, and after the formwork is removed, the shoring is once pulled out of the concrete arch and dismantled.

(Problem to be solved by the invention) However, if the arch-shaped support becomes long or flat, the stability during traveling becomes particularly poor, and in order to improve its stability, it is necessary to The tensile material 17 (
(Fig. 1 Sansho) alone may not be able to maintain safety, and removal by pulling out will also be extremely difficult.

The present invention solves the above-mentioned problems in removing arch-shaped supports, and in the case of long spans or flat arch-shaped supports, removal work can be carried out using a crane without moving them from the facility location. The aim is to make it possible to do so.

(Means for Solving the Problems) The structure of the present invention for achieving the above object will be described with reference to drawings corresponding to embodiments.
A plurality of half-arched trusses Al are arranged at intervals in the width direction of the arch concrete B to be constructed,
Connections 10, 1 (IL) A pair of structures are pin-coupled 3 to each other at the upper ends of the half-arch trusses A, Ax to form a cross-shaped formwork support A, which is then connected to each of the half-arch trusses A, , A, A large number of anchor bolts 12a, 12b, etc. are installed in the width direction of the arch concrete B, which is constructed by connecting the lower end to the abutment 1.1 with a pin 2.2, and cast using the shoring A. The anchor bolts 12a, 12b... and the half-arch trusses A, A,..., A2. Pulleys 13a, 13b-=, 14a, 14b are buried in the lower part of A2..., respectively, at intervals.
- attached and installed hoisting device 15.15 rope 16
．． 16 attached to the anchor bolts 12a, 12b... and the pulleys 13a, 13b... and the arch truss A1
．． The anchor ports 12d, whose terminals are buried in the arch concrete B, alternately span the pulleys 14a, 14b... attached to AI..., Ax, At...
Fixed at 12d, half arch truss A.

A1... A2A Yu...: Pull out the mutual coupling pins 3.3, let out the ropes 16.16, and create the half-arch truss AA1... A2. The structure is characterized in that a structure in which a plurality of A2... are connected is tilted and suspended around a connecting pin 2.2 at the lower end thereof.

(Example) Below, five examples of the present invention will be described with reference to the drawings.

Figure 1 shows a state in which the target object, arch form support A, has been installed and arch concrete B has been poured. The half-arch truss A, which is formed by dividing the arch form support A into two in the span direction, has a structure in which the lower ends of the half-arch truss A are connected with pins 2.2 and the upper ends of each half are connected with pins 3 to each other. There is. This arch form support A is a truss frame structure proposed in Japanese Patent Application Laid-Open No. 62-1905, etc., and is connected in a triangular shape by a main rod 5 and a pair of side rods 6 and 6, which are the upper chords of the truss. A large number of supporting elements 4 are connected to each other at the ends of the main rods 5, 5, and the connecting tops 8.8 of the side rods 6.6 are formed shorter than the main rods 5. The structure is such that they are connected by sub-rods 9, 9, which are the lower chord members of the truss. As shown in Fig. 4, each of the half-arch trusses A1Am is arranged at intervals in the width direction of the arch concrete B to be constructed, and is connected to each other by connecting members in, to, etc. . Then, an arch-shaped formwork 11 is erected on the support A, and arch concrete B is placed on top of the formwork 11.

In the present invention, the above arranged half-arch truss A
Anchor ports 12a, 12 are placed between each half-arch truss inwardly from the upper end of A2 and on the outside of arch concrete B.
b... is buried in the arch concrete H when it is placed.

Once the cast arch concrete B has hardened, first remove the formwork 11. Next, divide the shoring A into multiple connected structures of half-arch trusses A1 or A2, and suspend each truss one after the other. In this embodiment, the half-arch trusses A1 or A2 are divided into three connected sets. However, the number of half-arch trusses connected in each set may be two or three or more, and if the ability to suspend and lower the swinging device 15, rope 16, etc. is sufficient, , half-arch truss A
It is also possible to suspend the entire connected structure of 1 or A2.

Therefore, each anchor port 12 has a pulley 13a.
, 13b... are suspended, and each half arch truss A
,, Attach pulleys 14a, 14b, etc. to the lower part of A2, for example, using the side rod 6. Then, the rope 16 of the swinging device 15 installed on the ground is transferred from the pulley 13a suspended on the outside of the arch concrete B to the pulley 14a attached to the outside half-arch truss A1, and then sequentially to the pulley 13b - 14b - 13c - 14c. The end of the rope 16 is fixed to another anchor port 12d. And the connection 10.10 that is connected to this hanging set and another set adjacent to this
It removes.

Next, the rope 16.16 is pulled by the swinging device 15.15 to slightly lift the amphibious arch truss A, , A, , Am, A, and the load on the pins 3゜3 connecting them is released and the pins are removed. 3. Remove 3, both arch truss At,
This will untie the Ax.

Then, as shown in FIGS. 3 and 5, while the other arch trusses A- and Ax remain lifted, the rope 16 of the swing device 15 of one arch truss A, A is let out. go. As a result, the upper ends of the half-arch truss A, A are suspended by the pulleys 13.14, and the half-arch truss A is moved around the pin 2.2 that connects the lower end of the half-arch truss A, A to the abutment l. ,,
A will be tilted and lowered to be placed on the ground.

If this happens, there will be a large space between the arch concrete B and the half-arch trusses At, which have been lowered to the ground.
Half arch truss A1. It is possible to dismantle and transport the At on-site, or to transport the entire half of the truss. The other half-arch truss A2. At can also be carried out and removed in the same manner as described above.

In addition, the above-mentioned lifting and lowering work can also be performed on half-arch truss A and A8 at the same time.

(Effects of the Invention) As explained above, in the method according to the present invention, a half-arch truss is constructed by suspending a pulley from anchor bolts buried in poured arch concrete and a pulley from each half-arch truss, and using a rope hung on the pulley. Since the half-arch truss is suspended from the ground and tilted around the connecting pin at the lower end of the half-arch truss, it can be lowered to the ground, so even if it is a long span or a flat arch-shaped support, it is easy to remove the support. can be done easily, efficiently and safely. Therefore, large spans, which had difficulties in removing traffic supports,
Arch concrete construction with large arcs can now be performed, further expanding the scope of application of this type of arch form shoring, which is technically and economically superior, and further contributing to the development of the construction industry.
You will be able to contribute.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and Fig. 1 is a front view showing the arched formwork shoring structure being erected and arch concrete poured, and Fig. 2 is a front view showing the area where the formwork has been removed. A front view showing the state in which the shoring is suspended using pulleys and ropes,
Figure 3 is a front view showing the half-arch truss suspended, Figure 4 is an enlarged sectional view showing the half-arch truss suspended with pulleys and ropes, and Figure 5 is an enlarged view showing the half-arch truss suspended. FIG. A... Arched formwork support. AI A2... Half arch truss. ■...Abutment (or pier), 2.3-...Connecting pin 4.
...Supporting element, 5...Main rod. 6...Side rod, 7...Pin, 9...Secondary rod. lO-... Connecting material 11... Formwork. 12a, 12b, 12C = anchor bolt. 13a, 13b, 13c, 14a, 14b, 14c -
= Pulley.

Claims (1)

[Claims] A plurality of semi-arched trusses are arranged and connected at intervals in the width direction of the arch concrete to be constructed, and a pair of the structures are connected to each other with pins at the upper ends of the half-arched trusses to form an arched formwork support. This is constructed by connecting each lower end of a half-arch truss to the abutment with pins, and a large number of anchor bolts are placed at intervals in the width direction of the arch concrete into the arch concrete cast using the shoring. The rope of the hoisting device was buried, and a pulley was installed at the bottom of the anchor bolt and each half-arch truss.
The ropes are strung alternately between the pulleys attached to the anchor bolts and the pulleys attached to the arch truss, and the ends are fixed to the anchor bolts buried in the arch concrete.The connecting pins between the half-arch trusses are pulled out, and the rope is let out. A method for removing formwork support for arch concrete construction, which is characterized by tilting and lowering a structure in which multiple structures are connected together, using a connecting pin at the lower end of the structure as an axis.