JPS63181802A - Synthetic floor panel bridge - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a synthetic deck bridge made of a combination of section steel and concrete.

[Prior Art] In general, synthetic deck bridges have the advantage of having a lower girder height than other types of bridges, and are easy to construct.

FIG. 5 is a cross-sectional view showing the structure of a conventional composite deck bridge. In the figure, 10 is a steel deck slab with a substantially concave cross section, and the four circumferentially bent end plates 11 and the bottom plate 12 are It is formed into a so-called open cross section. Reference numeral 14 denotes T-beams arranged in parallel at predetermined intervals in the internal width direction of the steel deck slab 10 and extending in the longitudinal direction, and a protrusion 16 is protruded from the upper surface of the upper flange 15. . Reference numeral 18 indicates an upper reinforcing bar arranged slightly above the upper flange 15 of the T-beam 14, and 20 indicates an upper reinforcing bar placed inside the steel deck slab 10 on which the T-beam 14, the upper reinforcing bar 18, etc. are arranged as described above. It is made of concrete.

Therefore, as is well known, in the composite deck bridge constructed as described above, the compressive stress caused by the bending moment is mainly carried by the concrete, and the tensile stress is carried by the T-shaped steel, thereby achieving the required strength. I am getting .

[Problems to be Solved by the Invention] However, conventional composite deck bridges are inevitably heavier than composite girders, so they have the problem that they can only be used for bridges with relatively small spans. That is, when the span length exceeds about 20 m, the weight per unit area of the deck increases rapidly, which significantly impairs economic efficiency.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to obtain a lightweight and economical synthetic deck bridge.

[Means for Solving the Problems] A composite deck bridge according to the present invention includes a steel deck slab having a substantially concave cross section, and a steel deck slab arranged at predetermined intervals in the internal width direction of the steel deck slab. A T-beam extending in the longitudinal direction of the steel deck, reinforcing bars arranged slightly above the upper flange of the T-beam, and a reinforcing bar placed at the top of the T-beam near the center of the span of the steel deck. It consists of a space or lightweight material portion formed slightly below the flange, and concrete poured onto the space or lightweight material.

[Function] Since the composite deck bridge according to the present invention has a space section or a lightweight material section near the center of the span on the tension side of the deck, the bending moment and shear force are reduced by the absence of concrete in this section. It becomes smaller and lighter.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a cross-sectional view showing only the center left half of an embodiment of the present invention, and Fig. 2 is a longitudinal sectional view taken along line ■-■ in Fig. 1, also showing only the center left half. . Note that the same reference numerals as in FIG. 5 showing the conventional example indicate the same or corresponding parts.
Explanation will be omitted.

As shown in the figure, a formwork 22 is constructed between the end plate 11 and the 17 webs of the T-shaped steel 14 and between the webs 17 near the center of the span of the steel deck 10, and the formwork 22 and the bottom plate 12 A space 24 is formed therebetween. The formwork 22 only needs to have sufficient strength to support the weight of the concrete 20 placed thereon. therefore,
Instead of the formwork 22, for example, a lightweight material (not shown) such as styrene foam may be buried.

In the figure, 26 is a support schematically shown.

This embodiment is configured as described above,
Since there is no lower concrete near the center of the span of the steel deck 10 as in the conventional case, the bending moment and shearing force are reduced accordingly. FIGS. 3 and 4 are a bending moment distribution diagram and a shear force distribution diagram showing this relationship in comparison with a conventional example. In each figure, A shows the case of the conventional example, and B shows the case of the present invention.

In this way, since the bending moment is reduced, the weight of the T-shaped steel 14, the upper reinforcing bar 8, the bottom plate 12, etc. can be reduced accordingly. Further, since the shearing force near the center of the span is small, the shearing force can generally be borne only by the web 17 of the T-shaped steel 14.

Since the shearing force is large near the fulcrum, it is more advantageous to have the lower concrete also bear the shearing force than to have the web 17 alone bear the shearing force. Therefore, the formwork 22 is inclined 23 near the fulcrum and connected to the bottom plate 12. Furthermore, the shearing force near the fulcrum is also smaller than that of a normal synthetic deck bridge because there is less concrete near the center.

[Effects of the Invention] As described above, according to the present invention, since a space or a lightweight material portion is provided on the tension side near the center of the span of a synthetic deck bridge, bending moments and shear forces can be reduced. With this reduction, the weight of the structural elements can be reduced, and even if the span length becomes large, it can be manufactured economically.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an embodiment of the present invention, and Figure 2 is a cross-sectional view of the embodiment of the present invention.
3 is a bending moment distribution diagram of the conventional example and the present invention, FIG. 4 is a shearing force distribution diagram, and FIG. 5 is a cross sectional view of the conventional example. Explanation of main symbols in the diagram 10...Steel deck slab 14...T-shaped steel 15...
・Top flange 18...Top reinforcing bar 20...Concrete 22...Formwork 24...Space

Claims (1)

[Claims] A steel deck having a substantially concave cross section; T-beams arranged in parallel at predetermined intervals in the internal width direction of the steel deck and extending in the longitudinal direction of the steel deck; reinforcing bars arranged slightly above the upper flange of the T-shaped steel; a space or lightweight material portion formed slightly below the upper flange of the T-shaped steel near the center of the span of the steel deck; and the space. A composite deck bridge characterized by comprising concrete poured on a lightweight material section or a lightweight material section.