JPH0364001B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to formwork support applied to the construction of arch concrete in arch bridges and the like.

[Conventional technology]

Recently, in bridge structures such as roads and railways, deterioration of concrete slabs constructed on bridge piers,
Damage is becoming a major problem. Deterioration and damage to concrete slabs is due to the material properties of concrete that are strong in compression but weak in tension.Dry shrinkage and repeated moving concentrated loads cause cracks, and the reinforcing steel rusts and expands due to water entering through the cracks. It is thought that this will accelerate the concrete flaking, leading to further deterioration of the reinforced concrete.

Therefore, in order to deal with this kind of deterioration of concrete, bridge types that match the characteristics of concrete have been studied, and concrete arch bridges, which have been forgotten today, have been attracting attention. This arch bridge is an excellent structural type for a concrete structure because it becomes a compressed member throughout its cross section when a dead load is applied.This type of bridge prevents deterioration of the concrete and greatly improves durability. That is true.

However, when constructing a concrete structure such as an arch bridge, a major problem arises in terms of its construction, especially the formwork facilities required to construct the arch-shaped concrete between the piers. As a general example of this construction, each pier is first constructed to the required height, then arch-shaped formwork is erected between the piers and concrete is poured. If it could be supported by vertical supports, construction would be easy and economical, but in actual construction, the arch formwork and the outer formwork set opposite to it, The concrete poured between the two forms will be piled up sequentially from the bottom of both forms, so at the initial stage of concrete pouring,
The load on the concrete formwork acts perpendicular to the formwork surface. On the other hand, the pillars that support the formwork part can support the formwork in the vertical direction, but it is almost impossible to support them in the horizontal direction, because the angle of intersection with the arch support butterfly of the formwork deviates greatly from the right angle direction. . Therefore, the arch support butter needs to have a structure that can withstand horizontal loads by providing horizontal members. This necessarily results in a truss structure.

FIG. 5 shows an example of a conventional technique in which an arch-shaped formwork is supported by a truss structure. That is, when constructing the arch-shaped formwork 2 between the piers 1 and 1, an arch-shaped support 5 having a truss structure is installed and supported by the pillars 6 and the frame 7 in a manner inscribed in the formwork 2, and the formwork is mounted on it. The butterfly material 3 of the frame 2 is fixed and the weir board is stretched.

[Problem that the invention seeks to solve]

However, as can be seen from the above figure, the structure and shoring for supporting the arch-shaped formwork 2 are heavy structures made of trusses, and the construction thereof is large-scale. Moreover, the formwork and its supports must be assembled and dismantled repeatedly for each unit construction section to proceed with construction, and if the arch shape of the arch concrete changes, especially the shoring must be changed to the arch shape each time. At the same time, it had to be assembled in a new shape, which not only required complicated assembly and disassembly for each construction section and a lot of time, but also resulted in a lot of wasted materials and a huge expense. Become.

The present invention was made in view of such actual circumstances,
The formwork support applied to the construction of arch concrete formwork has been improved, and it is easy to assemble and dismantle, supports the formwork reliably and firmly, and makes positioning and adjustment of the formwork easy when erecting the formwork. Moreover, even if the shape of the arch to be constructed changes in various ways, it is an object of the present invention to provide an arch form support that can be assembled in a manner that adapts to the change.

[Means for solving problems]

The structure of the present invention will be explained with reference to FIGS. 1 to 4 corresponding to embodiments. In the present invention, a large number of support elements 15 formed in a triangle by combining a main rod 11 and a pair of side rods 12 are connected to each other. The ends of the main rod 11 are connected by pin connections 17, and the connecting portions 14 of both side rods 12 in each supporting element 15 are connected to the secondary rod 1.
8 are connected to each other to form an arch-shaped support 10 as a whole, and main rods 11 at both ends thereof.
The end portion of the main rod 11 is supported by an existing structure 1 such as a bridge pier, and each main rod 11 has a threaded rod 21 whose tip end is connected to the arched formwork 2, and its protruding length can be freely adjusted. It is characterized by the fact that it is provided in

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

In the figure, reference numerals 1 and 1 are leg structures constructed at predetermined intervals prior to placing the arch concrete 8, 2 is an arch-shaped formwork constructed between these leg structures, and 10 is an arch-shaped formwork constructed between the leg structures. The arch-shaped formwork 2 is an arch-shaped shoring structure that supports the arch formwork. It is formed by attaching a weir plate 4 to the outside of 3.

The arch-shaped shoring 10 has one end of each side rod 12, 12 tied to both ends of the main rod 11, 13, 13,
A large number of supporting elements 15 constructed in a triangular shape with their other ends fixed to each other via a connecting plate 14 are connected to each other by a pin 17, and the connecting plate 14 at the top of each supporting element 15 is connected to each other by a main rod. 11, and are connected by a sub-rod 18 shorter than 11 to form an arch-shaped truss structure as a whole. The sub-rod 18 may be attached to the coupling plate 14 by pin connection, but as shown in FIG. They may be fixed together by welding. The size of the curvature formed by this arch support 10 is determined by the length of the sub-rod 18. Therefore, the degree of curvature of the arch support 10 can be freely changed by changing only the length of the sub-rod 18, and the degree of curvature can also be changed depending on each support element.
It can be freely increased or decreased in units of 15, and can also be used to construct arch formwork with complex curves.

In addition, the main rod 11 of each supporting element 15 has a main rod 1
1, screw rods 21, 21 are attached,
The main rod 11 is held in place by tightening a pair of nuts 22, 22 screwed into the threaded rod 21, and by adjusting the position of the screwing relationship with the nut 22, the main rod can be fixed. The protrusion length from 11 is adjustable. And screw rod 21
The tip portion of the molding member 2 can be freely fixed to the butterfly material 3 of the formwork 2 by means of a pin 23.

As shown in FIGS. 1 and 2, the arch support according to the present invention includes brackets 24, 24 that fix the terminal parts of the main rods 11, 11 on the supporting elements 15, 15 at both ends to the piers 1, 1. The frame is fixed by pins 25, 25. The work involved in constructing the frame is the same as for general truss structures, and multiple rows of arch supports are installed at the required intervals in the depth direction of the arch concrete to be constructed. is the part of the connecting plate 14, the main rod 11,
They are connected to each other by connecting rods 26 at the side rods 12 and the like.

The formwork 2 is constructed on a constructed arch support. In other words, the main rod 11 of the arch shoring,
Place the butterfly material 3 on the outside of the butterfly material 11, insert the pin 23 into the pin hole of the butterfly material 3 prepared in advance and the pin hole at the tip of the screw rod 21, and connect it to the main rod 11 through the screw rod 21. The weir plate 4 is attached to the outer surface of the butter material 3. At this time, the position and arc of the formwork can be adjusted as appropriate by adjusting the protruding length of the screw rod with respect to the main rod 11.

After the formwork 2 is erected, an auxiliary formwork 27 is attached between the end of the formwork 2 and the pier 1, an outer formwork 28 is erected, and concrete 8 is poured between both formworks 2 and 28. do. After the concrete 8 hardens, the outer formwork 28 and the auxiliary formwork 27 are removed, and then the nuts 22 are removed.
By loosening one side and tightening the other to shorten the protruding length of the threaded rod 21, the formwork 2 will be drawn toward the main rod 11 via the butterfly material 3.
As a result, the formwork 2 is separated from the concrete 8 as shown in FIG.

After the construction of the arch concrete 8 is completed, the formwork is dismantled and removed, followed by the shoring. In this case, the pins 19, 19 are removed and the sub-rods 18, 1
8 is removed, and the connecting pins 17, 17 of each support element 15, 15 and the attachment pin 2 with the piers 1, 1 are removed.
It can be easily dismantled by simply removing the parts 5 and 25.

In addition, when the depth of the arch concrete 8 is long, it is a good idea to perform the construction in several stages in the depth direction. In such a case, install a long rail in the depth direction instead of the bracket 24 attached to the pier 1, and attach moving wheels to the end of the main rod 11 to make the arch support movable along the rail. As shown in FIG. 2, the formwork 2 can be moved to the next construction position without being dismantled in a state where it is separated from the concrete 8.

FIG. 4 shows an example of construction in which the direction of the butterfly material 3 in the formwork 2 is perpendicular to the main rod 11 of the shoring; in this case, the screw rod 21
It is possible to insert the flattened tip of the C-shaped material into the joining part of the butterfly material 3 made of two C-shaped materials and connect it to the butterfly material 3 by the pin 23 in the direction perpendicular to the pin 23 in the above embodiment. can.

〔Effect of the invention〕

As explained above, according to the present invention, a 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 the connecting portions of both side rods are Since the structure is such that they are connected to each other by sub-rods, the truss structure supporting the formwork is strong and easy to assemble and dismantle, and the shape of the arch can be changed simply by changing the length of the sub-rods. Therefore, it is possible to repeatedly apply the method to the construction of arch concrete of various sizes, and it is possible to save materials and labor. In addition, the arch-shaped formwork can be erected with screw rods that allow its relative position to be adjusted at will.
When constructing the formwork, it is easy to position the formwork and adjust the circular arc, and the formwork can be easily peeled off, among other excellent effects.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view showing an example of construction using shoring according to an embodiment of the present invention, FIG. FIG. 4 is an enlarged side view showing a part of the shoring, FIG. 4 is a side view showing another embodiment, and FIG. 5 is a side sectional view showing the state of construction using the conventional shoring. 1... Pier, 2... Arch formwork, 3... Bata material, 4
... Shelter plate, 8 ... Concrete, 10 ... Arch-shaped shoring, 11 ... Main rod, 12 ... Side rod, 14 ... Connection plate, 15 ... Supporting element, 17 ... Pin, 18 ... Secondary rod, 19 ... Pin, 20 ... Auxiliary plate, 21...screw rod, 22...nut, 23, 25...pin, 28...
Outer formwork.

Claims (1)

[Claims] 1. A large number of support elements formed into a triangle by joining a main rod and a pair of side rods are connected to each other by pin connections at the ends of each main rod, and the joints of both side rods in each support element are connected by sub-rods. They are connected to each other to form an arch-shaped support structure, and the terminal parts of the main rods at both ends are supported on existing structures such as bridge piers. A formwork support for arch concrete construction, characterized by having screw rods connected to the formwork whose protrusion length can be freely adjusted.