JPH03247805A - Construction method of diagonal hollow floor slab bridge - Google Patents

Abstract

PURPOSE:To make unnecessary a rigid connection method of bearings by arranging a specific number of T-shape steels on the bottom steel plate of a composite floor slab bridge, and placing concrete between the upper part of the T-shape steels and web element to form a hollow section between the bottom steel plate and concrete. CONSTITUTION:Four T-shape steels 2 are arranged on the bottom steel plate 1 of a composite floor slab bridge, an upper distribution bar 3 is placed to a position slightly higher than an upper flange 2a of each of the T-shape steels 2, and a lower distribution bar 4 is placed to the approximate 1/2 element of the height of a web. Concrete 5 is placed between the upper distribution bar 3 and lower distribution bar 4, and a hollow section 6 is formed between the bottom steel plate 1 and concrete 5, or the hollow section 6 is filled with foamable resin plate 7. According to the constitution, uplifts generated in acute angle sections of the floor slab bridge can be eliminated by substituting the concrete 5 for concrete having weight heavier than that commensurate with the uplifts generated in bearings in the acute angle sections thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method of constructing a diagonal hollow deck bridge.

``Conventional technology'' In recent years, bridges are often planned that give priority to road alignment. Therefore, compared to straight bridges, bridges constructed diagonally to the width of the river (slanted bridges), as shown in Fig. ) are common.

Generally, in a slanted bridge, stress generated in bridge members becomes complex due to live loads such as the weight of vehicles.

In particular, with composite girders, the deck slab near the end of the main girder is likely to be damaged, and negative reaction force (uplift) is likely to occur in the support at the acute angle part (points A and D of No. 111J). It is said that it is desirable that the oblique angle θ in FIG. 1 is not smaller than 60' (Japan Road Association Steel Road Bridge Construction Guidelines Handbook, February 1973 (revised August 1980)).

In addition, the Ministry of Construction's standard design rate for civil engineering structures, volumes 19 and 20, for Bretency 5-inch PC @ pure hollow deck bridges (1930)
In the 4th year revised edition), the bevel angle is limited to 60° or more.

Furthermore, reinforced concrete slab bridges have a large self-weight, and the usable diagonal span length (Ls in Figure 1) is limited to about 15 m.

Furthermore, steel deck slabs are too light in their own weight and cause a large uplift at the acute angles of the slanted bridge (points A and D in Figure 1). This requires a rigid construction method, which requires a large amount of cost and construction time.

Compared to these conventional bridges mentioned above, the composite deck slab f1 (Japanese Patent Application Laid-open No. 60-195205
In other words, synthetic deck bridges that have a hollow section in the deck section or synthetic deck bridges that have the hollow section filled with a material with a light specific gravity (foamed resin board) are most suitable for diagonal bridges. This has been revealed as a result of various studies.

"Problem to be Solved by the Invention" However, even in the synthetic deck bridge described in the above-mentioned published patent publication, there are cases where the oblique angle θ is smaller than 60 degrees, and the ratio of the width W to the diagonal span length Ls. If the angle is large, it is difficult to prevent uplift occurring at the acute angle points A and D, and as with the steel deck slab, there is a problem that requires a method of rigidly connecting the bearing to the abutment.

"Means for Solving the Problems" The present invention has been developed to solve the above-mentioned problems, and its first gist is to provide a diagonal slab bridge having a hollow part in the slab part. Alternatively, in a diagonal deck bridge in which the hollow part is filled with a material with a light specific gravity, concrete with a weight equal to or more than the uplift that occurs on the bearing at the acute angle part is poured into the hollow part located around the bearing. The purpose is to fill the concrete or replace the material with a light specific gravity located around the support with the concrete.

A second aspect of the present invention is that in a diagonal deck bridge having a hollow portion in the deck portion or a diagonal deck bridge in which the hollow portion is filled with a material with a light specific gravity, the support of the acute angle portion is provided. Either fill the hollow space located around the bearing with concrete of a weight equal to or more than the uplift that occurs, or replace the light material located around the bearing with the concrete, and form an obtuse angle. In order to cope with the bearing reaction force of the bridge, a rubber bearing that is approximately twice as thick as a straight bridge is used.

"Function" As mentioned in the first gist, in a diagonal deck bridge where the deck section has a hollow section or where the hollow section is filled with a material with a light specific gravity, there is a problem in the support of the acute corner. By filling the hollow part located around the bearing with concrete of a weight equal to or more than the weight required for the uplift, or by replacing the material with a lighter specific gravity located around the bearing with the concrete. , it is possible to eliminate the uplift that occurs at the acute angle portion, and therefore it is possible to eliminate the need for a method of rigidly connecting the bearing to the abutment.

Also, as mentioned in the second gist, in a diagonal deck bridge that has a hollow part in the deck section or a diagonal deck bridge in which the hollow part is filled with a material with a light specific gravity, uplift occurs in the support of the acute angle part. Filling the hollow space located around the bearing with concrete of a weight equal to or more than the weight of concrete, or filling the hollow part located around the bearing with a material having a lighter specific gravity,
In order to replace it with the concrete mentioned above and to cope with the bearing reaction force of the obtuse angle part, l1LJ! By using a rubber bearing that is approximately twice as hard as the rubber bearing, it is possible to eliminate the uplift that occurs at acute angles, and therefore it is possible to eliminate the need for the rigid connection method of the bearing to the abutment. The elastic deformation of the bearing can reduce the fluctuation range of the reaction force distribution on the bearing line.

"Example" Next, an example of the method for constructing a diagonal hollow deck bridge according to the present invention will be described below with reference to FIGS. 2 to 6.

First of all, what is shown in Fig. 2 is the basic form of a synthetic deck bridge that is most suitable for Yo4 Bridge, for example, plate thickness 6 Tsuru, bridge axis length 5200 vs. diagonal span length 4800 m5, and bearing width 3.
200 fi, width 1600 long, bevel 30' bottom net board 1
A protrusion 2 is formed on the upper surface of the upper flange 2a along the upper horizontal axis direction.
T type IN 2 (100ws x 100
4 w Slightly above the flange 2a, an upper force distribution reinforcing bar 3 with a diameter of 13WM is installed at a required interval (20
0fi), and lower force distribution reinforcing bars 4 with a diameter of 13 are placed at required intervals (200fi), penetrating orthogonally to almost each part of the height of the web portion of each T-shaped 1lI2 with protrusions, and Concrete 5 is cast from a position slightly below the reinforcing bars 4 to a position slightly above the upper distribution reinforcing bars 3 to create a diagonal composite floor slab having a hollow portion 6 between the top surface of the bottom mesh F1) and the bottom surface of the concrete 5. Build a bridge.

The one shown in FIG. 3 is a modified example of a synthetic deck bridge that is most suitable for diagonal bridges, in which a very light foamed resin board 7 with a specific gravity of 0.06 or less is installed in the hollow part 6. Fill it and construct a diagonal composite deck bridge.

Therefore, concrete 8 of a weight greater than that corresponding to the uplift occurring in the bearings of the acute angle portions of the diagonal composite deck bridge is poured into the hollow portions 6 located around the bearings as shown in Fig. 4 or 5 or 5. 6, or replace the foamed resin plate 7 located around the support with concrete 8, and then fill it as shown in FIGS. 4, 5,
As shown in Fig. 6, in order to cope with the bearing reaction force at the obtuse angle part of the diagonal composite deck bridge, a rubber bearing 9 (thickness 23 mm), which is approximately twice as thick as that of the first bridge, is installed on the bearing line. intervene.

"Effects of the Invention" As described above, the first gist of the present invention (in a diagonal deck bridge having a hollow section in the deck section or a diagonal deck bridge in which the hollow section is filled with a material with a light specific gravity) , Fill the hollow part located around the bearing with a concrete weight equal to or more than the uplift that occurs in the bearing at the acute corner, or fill the hollow part located around the bearing with a material with a light specific gravity located around the bearing, or fill the concrete By replacing it with
Therefore, the method of rigidly connecting the bearing to the bridge abutment can be made unnecessary, and the construction cost and construction period can be significantly reduced.

In addition, as in the second aspect of the present invention, in a diagonal deck bridge having a hollow portion in the deck portion or in which the hollow portion is filled with a material with a light specific gravity, problems occur in the support of the acute angle portion. Either filling the hollow part located around the support with concrete with a weight equal to or more than the weight of the amplifier lift, or
Alternatively, the light material located around the bearing may be replaced with the concrete, and a rubber bearing approximately twice as thick as that of the first bridge may be used in order to cope with the bearing reaction force at the obtuse angle part. Therefore, in addition to the effect of the first gist,
The elastic deformation of the rubber bearing has the effect of reducing the fluctuation width of the reaction force distribution on the bearing line.

As a result, the bridge is actually 30m long and 10m wide.
It becomes possible to construct a diagonal bridge (40° diagonal angle).

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a diagonal bridge, Fig. 2 is an explanatory diagram showing the basic form of a synthetic deck bridge that is most suitable for a diagonal bridge, Fig. 3 is an explanatory diagram showing a modification of the same, and Figs. FIG. 6 is a schematic plan view showing each embodiment of the method of the present invention. l...Bottom mesh plate 2...T-shaped steel with protrusion 2
a... Upper flange 2b... Protrusion 3... Upper load reinforcing bar 4... Lower load reinforcing bar 5... Concrete 6... Hollow part 7... Foamed resin board 8
...Concrete 9...Rubber bearing

Claims (2)

[Claims] (1) In a diagonal slab bridge that has a hollow section in the deck section or a diagonal slab bridge in which the hollow section is filled with a material with a light specific gravity, the weight of concrete is greater than the weight that corresponds to the uplift that occurs in the support of the acute corner section. A method for constructing a diagonal hollow deck bridge, characterized by filling the hollow portion located around the bearing, or replacing the material with a light specific gravity located around the bearing with the concrete. . (2) In a diagonal slab bridge that has a hollow section in the deck section or a diagonal slab bridge in which the hollow section is filled with a material with a light specific gravity, the weight of concrete is greater than the weight that corresponds to the uplift that occurs in the support of the acute corner section. In order to fill the hollow part located around the bearing, or replace the material with a light specific gravity located around the bearing with the concrete, and to cope with the bearing reaction force of the obtuse angle part, A method for constructing a diagonal hollow deck bridge characterized by using rubber bearings that are approximately twice as thick as a straight bridge.