JPH08253909A - Ferroconcrete floor slab for bridge and form therefor - Google Patents

Abstract

PURPOSE: To prevent a floor slab from being damaged under the heavy condition of traffic, and to improve labor-saving for form members, shortening of a construction period, safety, and profitability in the time of its construction. CONSTITUTION: A space truss-like reinforcement 2 wherein one upper chord member 7 and two lower chord members 8 are provided and spaces between the upper chord member 7 and the lower chord members 8 are connected with two sets of lattice members 9 bent in wave shape, is set up. A plurality of the reinforcements 2 are arranged parallel to each other and are joined to a steel plate 1 for a form. Main reinforcements 3 at the underside and distribution bars U at the underside are arranged above the steel plate 1, the distribution bars 5 at the upside and main rainforcements 6 at the upside are progressively arranged above the upper chord members 7 of the truss-like reinforcements 2, and reinforcements for a floor slab A which are also used as a form panel are set up. A unit of the reinforcements for the floor slab A is placed on a main girder for a bridge and concrete is placed thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a reinforced concrete floor slab used for a bridge superstructure and a formwork used for the construction.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional reinforced concrete floor slab used for a bridge superstructure. In a road bridge specification book, isotropic infinity simple supported simply by two opposite sides. The cross-sectional force is calculated assuming the plate, and the reinforcement arrangement in the main reinforcement direction and the distribution reinforcement direction is determined.
It is also stipulated that the checking of the shearing force of the floor slab does not have to be performed at that time.

[0003] On the other hand, Japanese Utility Model Laid-Open No. 157219 / Showa 56-157219 discloses a wire mesh for the purpose of ensuring rigidity and improving workability of formwork and reinforcing bar construction due to the large span of a reinforced concrete floor slab used as a floor slab of a building. It describes a reinforced concrete floor slab in which a plurality of rows of truss beams made of reinforcing bars are arranged on a weir board made of, and a highly rigid lattice lath is arranged between the truss beams and the wire mesh, and concrete is cast.

Further, in Japanese Utility Model Laid-Open No. 3-84327,
Regarding the precast concrete slab used in the lower part of the floor slab of the building, the two pairs of plane trusses that connect one upper chord member and one lower chord member with a lattice material are made to approach the upper chord member side and the distance between the lower chord members It is described that a truss rebar having a structure arranged at a position is used, the lower chord side is embedded in the concrete of a precast concrete plate, and the upper chord side is projected so that it can be integrated with cast-in-place concrete.

[0005]

In the reinforced concrete floor slabs used for bridges, wheel load from large trucks and the like has caused destruction in places with heavy traffic about 10 years after completion of service. For this reason, due to revisions to the specifications for road bridges, the requirements for thickening floor slabs and shortening floor spans have been changed.

However, it cannot be said that the existing floor slabs having no shear reinforcing bar can completely prevent the fracture because the fracture property thereof finally shows shear fracture.

[0007] In addition, since the casting of concrete itself is generally performed in-situ, a formwork using wood is mainly used, and it is necessary to scaffold the entire surface. Improvement from the aspect and construction period is desired.

The present invention is intended to solve the problems in such a reinforced concrete floor slab for bridges, can prevent the floor slab from being damaged under heavy traffic, and save labor of the formwork material in construction, It is an object of the present invention to provide a reinforced concrete floor slab for bridges, which can shorten the construction period, improve safety and economy, and a formwork used for the construction of the floor slab.

[0009]

A reinforced concrete floor slab for bridges according to claim 1 of the present application comprises one upper chord member, two lower chord members arranged at intervals, an upper chord member and each lower chord member. The truss rebar, which is made up of a lattice material that connects the On the upper main rebar arranged orthogonally to the upper distribution bar, and on the lower and upper part of the truss rebar as the formwork steel plate as a formwork (formwork that is not removed after concrete placement) and above the formwork steel plate. Consists of lower distribution bars arranged orthogonal to the lower chord members of the truss reinforcement, lower main reinforcing bars arranged perpendicular to the lower distribution bars, and concrete cast on the form steel plate. It is characterized by.

The truss rebar and the form steel plate are joined together by, for example, welding the lower chord member of the truss rebar and the form steel plate by welding, or by making the lattice member of the truss rebar project downward from the lower chord member. It is conceivable that the lower end of the material and the form steel plate are joined by welding or another method.

The reinforced concrete floor slab for bridges according to claim 2 of the present application is the latter case of joining the truss reinforcing bar and the form steel plate, and the lower chord member of the truss reinforcing bar is connected to the lattice member above the lower end of the lattice member. This is the case where the lower end of the lattice member and the form steel plate are joined, and the lower main reinforcing bar and the lower distributing force bar are placed and arranged on the lower chord member. In this case, it is not necessary to separately support the lower main reinforcing bar and the lower distribution reinforcing bar with a spacer or the like, which improves the workability.

The formwork of the reinforced concrete floor slab for bridges according to claim 3 of the present application is a formwork used for the reinforced concrete floor slabs for bridges according to the above-mentioned claims 1 and 2, and one upper chord member and a space Truss rebars consisting of two lower chords that are placed at intervals and lattices that connect the upper chord and each lower chord are arranged in parallel in the direction of the main rebar of the floor slab, and the truss rebar and bridge It is characterized in that it is joined and integrated with a form steel plate as a scrap frame forming the lower surface of the reinforced concrete floor slab by welding or another method.

[0013]

In the present invention, the main reinforcing bar and the distributing reinforcing bar of the reinforced concrete floor slab used for the bridge superstructure remain the same as before, and the truss reinforcing bar in which one upper chord member and two lower chord members are connected by the lattice member is used. It has a structure in which it is arranged in the same direction as the main rebar of the floor slab at a predetermined interval, and this is placed on a form steel plate and joined.

By adopting such truss rebar,
In the present invention, the shearing force can be smoothly transmitted in the direction of the main reinforcement of the floor slab to prevent the floor slab from being damaged under heavy traffic.

Further, the truss rebar is used together with the form steel plate,
Since it also has the function of the main member as a steel formwork, it leads to a significant labor saving of formwork materials.

By using the truss reinforcing bar, the bending work of the main reinforcing bar becomes unnecessary, and the panel and the truss reinforcing bar are integrated on the main bridge girder as a panel in which the main reinforcing bar and the distribution reinforcing bar are previously integrated by binding wires. It is possible to complete the floor slab by erection and pouring concrete, shortening the construction period in the form of steel form panel construction method like this, and omitting the entire scaffolding, and the safety and economy are significantly improved. To be done.

[0017]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 3 shows an example of the truss reinforcing bar 2 used in the present invention. One upper chord member 7 and two lower chord members 8 are shown.
The upper chord member 7 and the lower chord member 8 are connected by two sets of wavy lattice members 9 to be assembled into a three-dimensional truss shape.

FIG. 2 shows a form member B in which a plurality of the truss rebars 2 are arranged in parallel and joined to and integrated with a form steel plate 1 as a scrap frame. Claim 3 of the present application Corresponding to.

FIG. 1 and FIG. 4 show a state (formwork floor slab A) before placing concrete for one embodiment of a reinforced concrete floor slab for bridges according to the invention of claim 1 of the present application. On the form member B formed as described above, the lower main reinforcing bar 3 is arranged, and further the lower distributing bar 4, the upper distributing bar 5, and the upper main reinforcing bar 6 are arranged in order, with a binding wire or the like. It is formed by binding.

After assembling the one-panel form slab A formed in this way at the factory or on site, it is erected on the main bridge girder (after erection of the form member B, other rebars can also be assembled). Possible), concrete is poured. At that time, the form member B formed from the steel plate 1 and the truss rebar 2 shown in FIG. 2 supports the concrete weight.

After the concrete is hardened, the bending moment generated by the wheel load as a reinforced concrete floor slab is resisted by the main reinforcing bars 3 and 6 and the distributing bars 4 and 5, and functions as a shear reinforcing bar for transmitting the shearing force. Use truss rebar 2 to resist. This can prevent shear failure due to fatigue of the reinforced concrete floor slab.

FIG. 5 shows a state before pouring concrete for one embodiment of the invention according to claim 2 of the present application (form slab A).
Is shown.

In this embodiment, the floor slab according to claim 1 (see FIG.
The lower chord member 8 of the truss reinforcing bar 2 in FIG.
Is connected to the lattice member 9 in a form of being moved from the lowermost end of the floor chord member 7 to the upper chord member 7 side, and the lower main reinforcing bar 3 and the lower distributing force bar 4 of the floor slab are placed on the lower chord member 8 And the form steel plate 1 are joined.

In this case, the upper and lower main rebars 3, 6 and the force distribution rebars 4, 5 can be positioned and supported by the truss rebar 2, and it is not necessary to install a spacer or the like on the form steel plate 1.

[0026]

EFFECTS OF THE INVENTION The truss reinforcing bars embedded in the floor slab can prevent shear failure of the floor slab under heavy traffic.

By integrating a form steel plate as a discard form and a truss rebar that also functions as a main member of the form,
The steel form panel method can be implemented and the construction period can be shortened. In addition, it becomes possible to omit the scaffolding on the entire surface, which improves safety.

The economic efficiency is improved by improving the workability and shortening the construction period.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the invention according to claim 1 of the present application.

FIG. 2 is a perspective view showing an embodiment of the invention according to claim 3 of the present application.

FIG. 3 is a perspective view showing an example of truss reinforcing bars used in the present invention.

FIG. 4 is a sectional view corresponding to FIG. 1 in a direction perpendicular to the bridge axis.

FIG. 5 is a cross-sectional view in the direction perpendicular to the bridge axis showing an embodiment of the invention according to claim 2 of the present application.

FIG. 6 is a perspective view showing an example of a conventional reinforced concrete floor slab for bridges.

[Explanation of symbols]

A ... Formwork floor slab, B ... Formwork member, 1 ... Formwork steel plate, 2 ... Truss reinforcing bar, 3 ... Lower main reinforcing bar, 4 ... Lower distributing bar, 5 ... Upper distributing bar, 6 ... Upper main Reinforcing bar, 7 ... upper chord, 8 ... lower chord, 9 ...
Lattice material

Claims (3)

[Claims] 1. A plurality of the upper chord members, two lower chord members arranged at intervals, and a lattice member connecting the upper chord member and each lower chord member, wherein a plurality of them are arranged in the direction of the main reinforcing bar of the floor slab. Truss rebars arranged in parallel, upper distribution bars arranged orthogonally on the upper chords of the truss rebars, and upper main bars arranged orthogonally to the upper distribution bars on the upper distribution bars When,
Form steel plate as a scrap frame joined to the lower part of the truss rebar, a lower force distribution bar arranged above the form steel plate so as to be orthogonal to the lower chord member of the truss rebar, and the lower force distribution A reinforced concrete floor slab for bridges, comprising a lower main reinforcing bar arranged so as to be orthogonal to the reinforcing bar and concrete cast on the form steel plate. 2. The lower chord member of the truss rebar is connected to the lattice member above the lower end of the lattice member, the lower end of the lattice member and the form steel plate are joined, and the lower main reinforcing bar and the lower side The reinforced concrete floor slab for bridges according to claim 1, wherein a distribution bar is placed on a lower chord member of the truss rebar. 3. A truss rebar composed of one upper chord member, two lower chord members arranged at intervals, and a lattice member connecting the upper chord member and each lower chord member with truss rebars A plurality of reinforced concrete floor slabs for bridges, characterized in that they are arranged in parallel in a plurality of directions, and the truss rebar and a form steel plate as a scrap frame forming the lower surface of the reinforced concrete floor slab for bridge are joined and integrated. Formwork.