JPH0781244B2 - Composite slab bridge and its construction method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic slab bridge and concrete so that girders (ribs) in the axial direction of the bridge are embedded in the upper surface of the bottom plate portion of a steel shell having a U-shaped cross section orthogonal to the bridge. The composite slab bridge, which is constructed by laying a bridge to construct a bridge, has a large dead weight because the weight of the bridge itself is heavy, and a span of about 15 to 16 m is a limit from the economical aspect.

Therefore, as a means for reducing the dead load of this type of composite slab bridge, a pipe is installed in the synthetic slab bridge in the axial direction of the bridge, and concrete is placed so as to surround the pipe to remove the concrete portion. It is designed to reduce the weight (Japanese Utility Model Laid-Open No. 63-171416), or the tensile area of the synthetic floor slab is filled with cavities or lightweight padding such as foam steel, and a concrete layer is formed on it. (Japanese Patent Laid-Open No. 63-181802).

[0004]

However, according to the former structure, since the pipe is embedded in the concrete layer, the amount of concrete to be cast corresponding to the space portion is reduced, but the pipe and the concrete layer below it are placed. Since it will be used in the tensile area of the bridge, it is prone to cracking, and rainwater etc. infiltrate to cause rust on the steel shell, resulting in a structure with poor durability. In addition, the pipe is pushed up by the concrete at the time of pouring the concrete, so that it is necessary to provide a fixing jig for preventing the pipe from floating, which is not preferable because the additional structure increases.

According to the latter structure, since the lower part of the concrete layer only contains a cavity or a filling material substantially unrelated to the bridge, the water infiltrated from the concrete layer, as in the former case, is absorbed into the inner surface of the steel shell. There is a problem that the life of the bridge is shortened by rusting the steel shell from the inside.

On the other hand, in designing and constructing civil engineering structures including bridges, it is strongly demanded socially to have a function and shape suitable for environmental conditions from the viewpoint of environmental protection. That is, the former belongs to a recycling system that complies with the law of nature, and has a so-called recycling function for the purpose of resource saving and waste reduction, while the latter has a visual feature in the natural or urban environment. However, there is a demand for a design that is psychologically matched and has an excellent so-called landscape. Particularly in the industry, there is a demand for a comprehensive policy to utilize this philosophy for the design and construction of public structures and to improve the technology in this field.

In view of the above-mentioned points, the present invention is configured such that the area constituting the tensile area of the bridge is made of a hard urethane layer by a method which does not require a special jig or technique of spraying or pouring at the site or in the factory. In order to reduce the dead load of the slab bridge to a great extent, at the same time to reduce the bulk of the rigid urethane layer by making it lightweight and rigid, at the same time, by incorporating lightweight, hard and bulky waste in this rigid urethane layer, a large amount of recycling is possible. The hard urethane layer containing this waste is closely adhered to and integrated with the inner surface of the steel shell and the abdominal plate surface of the ribs to prevent water and air from contacting the steel shell and prevent rust. At the same time, the vibration damping effect is exhibited and a bridge that does not vibrate is provided. It is an object of the present invention to provide a synthetic deck slab that has a low bridge height, is lightweight, has high economic durability, and is resistant to vibration, and a construction method thereof.

[0008]

[Means for Solving the Problems] In order to achieve recycling of wastes while solving the above-mentioned problems, a steel shell having a U-shaped cross section orthogonal to the bridge axis direction and a bottom plate of this steel shell. The upper surface of the rib is fixed at a predetermined distance from each other in the axial direction of the bridge and has a height up to the compression cross section and a flange at the upper end, and the inner surface area of the steel shell filled in the tensile cross section and the rib antinode. A hard urethane layer with built-in waste, which is solidified by adhering to the plate area and burying empty cans, waste materials, plastic materials, and other light, hard and bulky waste materials inside, and the upper ends of the ribs on the hard urethane layer. A composite floor slab bridge is characterized in that it is constructed with a concrete layer that has been cast into the bridge, and claim 2 is a bridge slab in the bridge axis direction and a flange at the upper end. A rib having a height up to the compression cross section At a predetermined interval, they are fixedly erected by welding or the like, and the foamable hard urethane foam with closed cells is laid to the required thickness between the ribs and between the ribs and the side plates of the steel shell by spraying, etc. Empty cans, waste materials, plastic materials, and other light, hard, and bulky wastes are installed directly or in blocks, and the hard urethane foam is filled so as to be covered by spraying, etc., and foamed and solidified. By doing so, a rigid urethane foam is bonded and fixed to the inner surface of the steel shell and the abdominal plate surface of the rib to form a solid urethane layer with built-in waste, and concrete is placed on the upper surface of this rigid urethane layer to form a synthetic floor slab. It is in the construction method of the synthetic slab bridge characterized by the above. And claim 3
A unit in which the steel shell is divided into a plurality of pieces along the bridge axis direction at the bottom plate portion and a hard urethane layer containing waste is formed in advance between the ribs on each bottom plate portion in a factory etc. It is characterized by joining the edges of the parts together to form a steel shell, and injecting hard urethane foam between the units by filling it in-situ and then placing concrete on it to form a composite floor slab. The hard urethane foam is used to build up and solidify the waste to form a block having a predetermined external dimension, and the block is embedded in the hard urethane layer. The lock is embedded in the hard urethane layer. According to claim 4, the empty can, the waste material, the plastic material, and other light and hard and bulky waste are built-in, and the predetermined external dimension is made by the hard urethane. The block used for the synthesis floor slab bridge, etc., characterized in that formed in the lock shape it is an aspect 5.

[0009]

With the above construction, the hard urethane layer with built-in waste, which is constructed on the bottom plate of the steel shell, is adhesively fixed to the inner surface of the steel shell and the abdominal plate surface of the rib, and the weight of the concrete placed on it. Is supported by the cooperative action of hard urethane and the waste that is integrally fixed by this, and after the concrete is hard, the concrete floor slab, ribs, and steel shell maintain the strength as a bridge. There is no concrete layer in the tensile area of the composite slab bridge, and a hard urethane layer containing waste is closely adhered to the inner surface of the steel shell and the rib's abdominal plate surface. Since the urethane layer constitutes the tensile zone, only a compressive load acts on the concrete layer, which does not cause cracks in the concrete layer, and even if water intrudes from the concrete layer. In addition, since the hard urethane layer covers the internal waste in a hermetically sealed state and is firmly fixed to the inner surface of the steel shell and the rib's abdominal plate surface, water infiltration and the rib's abdominal plate surface are tightly fixed. As a result, water penetration and rusting can be prevented. In addition, since the upper ends of the ribs on the bottom plate of the steel shell are embedded in the concrete layer, the use of a Statgibel or other appropriate connector will not hinder the composite effect of the composite floor slab, and the steel shell and built-in waste It shows the behavior as a synthetic slab bridge in which the hard urethane layer and the concrete layer are integrated, making it a tough, vibration-resistant synthetic slab bridge. Still, since the dead load is greatly reduced, the span and bridge height can be increased, and at the same time, a large amount of waste can be recycled, which reduces the amount of hard urethane used and makes it economical. In addition, even if the concrete floor slab is damaged by a severe wheel load, the hard urethane layer underneath it that has sufficient vertical supporting force will cause a depression like the conventional concrete floor slab supporting method. No destruction occurs. Therefore, secondary traffic accidents due to depression can be prevented, and major improvements and improvements in safety management can be expected.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 1 is a perspective view showing a cross section orthogonal to the bridge axis, and FIG. 2 is an enlarged cross section of a part thereof. As shown in FIG. 2, the cross section orthogonal to the bridge axis has a shallow U-shape upward. A plurality of ribs 2, 2 made of a steel plate material having an upper surface of a bottom plate portion 1a of a steel shell 1 made of a steel plate having a plate thickness of about 6 to 9 mm are fixed to each other at predetermined intervals in the bridge axial direction by welding or the like. The position of the flange 2a at the upper end of the ribs 2, 2 ...
It is set at a height position existing in the compression zone X beyond the neutral axis Z of the compression zone X and the tension zone Y.

The side plate 1 of the steel shell 1 constructed as described above
b between the ribs 1 and 2 and the ribs 2 and 2, and between the ribs 2 and 2, the closed surfaces of the side plates 1b and 1b, the belly plates of the ribs 2 and 2, and the bottom plate 1a. Hard urethane foam is laminated to a required thickness by spraying, etc., and an empty can 3 (iron can) as waste is placed inside the hard urethane layer formed in this way, and again foamable hard from above. A urethane foam is sprayed and coated, an empty can 3 is further placed on the urethane foam, and the foamable hard urethane foam is coated again, and a waste-embedded hard urethane layer 4 is formed in a region corresponding to the height of the tensile region Y. To be done.

At the time of burying the empty cans 3, the empty cans 3 may be laid side by side at the time of construction or side by side as shown in FIG. 4, but as shown in FIG. A block 5 having a predetermined outer dimension is formed by covering and solidifying the empty can 3 with a foamable hard urethane foam, and the block 5 is transported to a bridge construction site to transport the inner surface of the side plate 1b of the steel shell 1 and the belly plate of the rib 2. If a block 5 is spread after a hard urethane layer is formed on the surface and the top surface of the bottom plate portion 1a, the workability is good and the block 5 itself can be recycled.

In any case, the hard urethane, which is constructed by incorporating the empty can 3, is integrally and closely fixed to the inner surface of the steel shell 1 and the abdominal plate surfaces of the ribs 2, 2 ... When foaming and solidifying. It Polyurethane foam, for example, is used as the closed cell foamable hard urethane used here, and it is hard and has a compression load resistance of about 2.5 kg / cm ² . Examples of this hard urethane include liquid T (polymethylene polyphenyl isocyanate, modifier) and R
A product produced by contacting two components of a liquid (polyether / polyol, catalyst, surfactant, foaming agent) is used. In addition, a material having the above-mentioned compression load resistance, a closed-cell foam material, a low ignitability, a heat resistance, and a high heat resistance may be selected.

After the solid urethane layer 4 with built-in waste is solidified, a reinforcing bar 6 is assembled on the solid urethane layer 4 and a part of the reinforcing bar 6 is passed through the ribs 2, 2 ... As shown in FIG. Form 7. And asphalt or the like is laid on the upper surface of the pavement 8. Ground cover parts 9 and 9 are formed on both sides of the concrete layer 7 in the bridge axis direction, and balustrades are installed on the ground cover parts 9 and 9 as necessary. An example of the appearance after the completion is shown in FIG.

In the present invention, as wastes contained in the waste-containing hard urethane layer 4, in addition to the empty cans 3, construction waste materials (wood, concrete lumps, etc.), synthetic resin waste materials (plastic materials, styrofoam lumps, etc.), etc. Can be used.

When the bridge length is 25 m, the total width is 8.7 m, the thickness of the hard urethane layer 4 with built-in waste is 700 mm, and the number of ribs 2 is seven, the amount of 250 mml empty cans can be buried. It will be about 150,000. In the case of an iron empty can, the load capacity in vertical use is about 10 kg / cm ^2, which is larger than the load capacity of hard urethane after hardening, so it can support the concrete weight when placing concrete,
It can fully fulfill the supporting function until the concrete is solidified.

FIG. 5 is a cross-sectional view showing another embodiment of the construction method according to the present invention, in which the bottom plate portion 1a of the steel shell 1 is divided into a plurality in the bridge axis direction, and the bottom plate portions 1a are close to both side ends in the longitudinal direction. Ribs 2 and 2 are erected at the positions, between the ribs 2 and 2, and between the ribs 2 and 2.
Waste-embedded hard urethane layers 4 ', 4, 4'on the outer side of 2
To form units 10, 10 ...
The bottom plate portions 1a of 0 and 10 and the joint portion 11 of the 1a are integrated at the bridge construction site by welding or bolt joints as shown in the drawings, and the waste-embedded hard urethane layers 4'at opposite ends are integrated.
Hard urethane foam is injected and foamed in the space between 4'and filled, and after hardening, concrete is poured to form a synthetic floor slab.

According to this, since the main waste-embedded hard urethane layer 4 is installed in the factory to manufacture the unit 10 and the unit 10 may be transported to the cross-linking site and assembled, the cross-linking site may be assembled. The work amount of can be greatly reduced.

Next, the test results will be described.

The safety of the synthetic slab bridge filled with hard urethane having a compressive strength of about 2.5 kg / cm ² has been verified by static loading experiments, fatigue experiments and the like using beam test specimens. This data is described in Japanese Patent Application No. 3-56068.

Here, it was verified by a compression test whether or not the inclusion of an empty can in the hard urethane layer affects the compression strength and the deformation history. The test body 11 used for this compression test has a center of a rectangular solid rectangular urethane block 12 having a rectangular cross section with a height of 350 mm and a side of 237 mm, as shown in the longitudinal section in FIG. 8 and the transverse section in FIG. 11 has four built-in four iron empty cans 3, 106 having a height of 106 mm and a diameter of 53 mm, which are placed between the contact plates 13, 13 of the hydraulic compression tester as shown in FIG. The stress and strain at the time of pressurization were tested by applying pressure in the direction of the white arrow.

As a result of the above-mentioned test, as shown in FIG. 12, even if the test body 11 having the empty cans 3, 3, ... However, it was found that resistance was exhibited even in a region where the strain was large. That is, in the test body 11 with a built-in can, the maximum stress level (elastic limit) in the elastic range did not change, and the stress level increased even if the strain increased. Then, the situation in which the strain exceeds the elastic limit at the time of pressurization of the test body 11 is gradually generated from the end portions in contact with the contact plates 13, 13 as shown in FIG. Since it is shown, it is also clear that it does not immediately affect the built-in empty cans 3, 3.

On the other hand, a test was carried out for vibration characteristics when hard urethane was used. As the test body, as shown in FIG. 13 (A) to (C), the cross-sectional tensile region is filled with the hard urethane 12 (a), and all the concrete 14 is filled with the test body (b). Three types of test bodies (c) were prepared in which the hard urethane 12 portion of the test body (a) was used as the cavity 15, and the center was hit with an impulse hammer to generate free vibration with a span of 4 m.

As a result, FIG. 14 (A), (B), (C)
As is clear from the vibration acceleration waveform in the center of the span shown in Fig. 2, the test body (a) filled with the hard urethane 12 is
It was confirmed that the test samples were damped earlier than the test samples (b) and (c), and it was confirmed that the vibration damping effect was high.

[0026]

As described above, according to the present invention, a steel shell is used as a mold, which requires a special structure and jigs such as the one in which the pipe is buried and the cavity is formed. The foamed hard urethane with closed cells is applied to the inner surface of the side plate of the steel shell, the belly plate surface of the rib, and the upper surface of the bottom plate of the steel shell by spraying or pouring, and then the urethane is filled so that waste is built in. By foaming it, the hard urethane layer with built-in waste adheres tightly to the inner surface of the steel shell and the rib abdominal plate surface, making it possible to pour floor slab concrete without using a special jig. The weight of concrete can be sufficiently resisted by the hardened urethane layer with built-in waste, and at the same time the amount of expensive hard urethane used can be greatly reduced by the built-in waste, which can greatly contribute to cost reduction. . In addition, the built-in waste has a hard urethane that encloses it and functions as a binder by binding the wastes together, and the wastes do not separate even when subjected to repeated load or vibration. After completion, the waste built-in hard urethane layer does not affect the strength of the bridge, so there is no problem. Through these measures, we can effectively use waste and achieve the purpose of recycling, while significantly reducing the dead load of the synthetic slab bridge, making it possible to bridge at low cost and produce a great economic effect. it can.

Further, the waste-embedded hard urethane layer adheres to the inner surface of the steel shell and the abdominal plate surface of the rib to be gelatinized, and the hard urethane itself is a closed cell and has no water permeability.
Water and air do not come into contact with the inner surface of the steel shell below the waste-embedded hard urethane layer or the abdominal plate surface of the ribs, increasing the rust-prevention effect and effectively improving the durability of these members and vibration. A bridge that exhibits a damping effect and is light in weight and has a low bridge height but is hard to vibrate can be obtained.

According to the third aspect, since the hard urethane layer with built-in waste can be formed in advance at a place other than the bridge construction site such as a factory, the work amount at the construction site is reduced,
The period required for cross-linking is shortened to that extent, and the construction period can be shortened.

Further, by coating the waste with hard urethane to solidify it into blocks as in claims 4 and 5, the workability at the cross-linking site is good, and the work can be performed with high efficiency, and other uses. There is an advantage that can be diverted to.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment showing a cross section orthogonal to a bridge axis of a composite deck slab according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a part of FIG.

FIG. 3 is a partial perspective view showing the relationship between ribs and reinforcing bars.

FIG. 4 is a partial cross-sectional view showing a modified example of a method of incorporating waste in FIG.

FIG. 5 is a sectional view showing another example of the construction method according to the present invention.

FIG. 6 is a perspective view showing an example of a case in which waste is built into a block.

FIG. 7 is an external view showing an example of a bridge to which the present invention has been applied.

FIG. 8 is a vertical cross-sectional view of a compression test specimen.

FIG. 9 is a transverse sectional view of the same.

FIG. 10 is a front view of the test body of FIG. 8 set on a tester.

FIG. 11 is a front view showing the deformation state of the test body during compression.

FIG. 12 is a stress-strain curve diagram obtained by a compression test.

13A to 13C are cross-sectional views of three types of test bodies for vibration damping tests.

14 (A) to (C) are vibration acceleration waveform diagrams of each test body of FIG. 13.

[Explanation of symbols]

 1 Steel Shell 1a Bottom Plate 1b Side Plate 2 Rib 2a Flange 3 Waste Can 4 Hard Urethane Layer with Waste 5 Block 6 Reinforcing Bar 7 Concrete Layer 8 Pavement 9 Ground Cover 10 Unit 11 Joint

Front page continuation (72) Inventor Sadaji Ota 1-9-1, Innai, Funabashi City, Chiba Prefecture Room 408 (72) Inventor Toshiyuki Ogawa 1-1-7 Maizuru Town, Oita City, Oita Prefecture Stock Company Sato Gumi (72) Inventor Shinichi Yamada 4-19-12 Koganehara, Matsudo-shi, Chiba (56) References: Kaihei 4-37612 (JP, U)

Claims (5)

[Claims] Claim: What is claimed is: 1. A steel shell having a U-shaped cross section orthogonal to the bridge axis direction, and a bottom plate of the steel shell. A rib with a height and a flange at the upper end, and an adhesive filled and solidified in the inner surface area of the steel shell and the abdominal plate area of the rib that is filled in the tensile cross-section area and emptied empty cans, waste materials, and other light, hard and bulky wastes A composite floor slab bridge comprising a hard urethane layer containing waste and a concrete layer placed on the hard urethane layer including the upper ends of the ribs. 2. A rib having a flange at the upper end and having a height reaching a compression cross-sectional area is predetermined with respect to the upper surface of the bottom plate portion of the steel shell having a U-shaped cross section orthogonal to the bridge axial direction. It is fixedly erected by welding etc. at intervals, and the foamable hard urethane foam with closed cells is laid by spraying etc. between the ribs and between the ribs and the side plate of the steel shell to the required thickness, and then vacant above it. Cans, waste materials, and other light, hard and bulky wastes are installed directly or in blocks, and the hard urethane foam is filled from above to cover them by spraying, etc.
By foaming and solidifying this, hard urethane foam forms a hard urethane layer with built-in waste that is adhesively fixed to the inner surface of the steel shell and the abdominal plate surface of the rib, and forms the hard urethane layer with built-in substance of this hard urethane layer, A method for constructing a synthetic slab bridge, characterized by placing concrete on the upper surface of this hard urethane layer to form a synthetic slab. 3. A unit in which the steel shell is divided into a plurality of pieces at the bottom plate portion in the bridge axis direction, and a hard urethane layer containing waste is formed in advance between the ribs on each bottom plate portion in a factory or the like. At the cross-linking site, the steel plate is integrally formed by joining the edges of the bottom plate to form a steel shell. Between the units, hard urethane foam is cast in situ to fill it, and then concrete is placed on it to form a composite floor slab. The method for constructing a synthetic slab bridge according to claim 2, wherein 4. A block having a predetermined external dimension is formed by incorporating and solidifying the waste with a rigid urethane foam, and the block is embedded in the rigid urethane layer. The construction method of the composite slab bridge described in 2 or 3. 5. A block used for a synthetic floor bridge or the like, characterized in that an empty can, a waste material and other light and hard and bulky wastes are built in and made of hard urethane in a block shape having a predetermined outer dimension.