JP6861431B2 - Steel deck instant bridge - Google Patents

Description

The present invention relates to steel slab instant bridges, in particular steel slab instant bridges comprising steel slab panels stiffened by vertical and horizontal ribs.

There are about 720,000 bridges in Japan, and about 74% of them have a bridge length of 2 m or more and less than 15 m (hereinafter, the bridge with such a bridge length is referred to as a "small span bridge"). A sub-branch bridge is one in which a floor slab (sometimes called a floor plate) is installed on a main girder arranged parallel to the bridge axis, and the floor slab is a steel slab mainly made of steel. There are concrete slabs mainly made of concrete and synthetic slabs made of steel and concrete. Hereinafter, a bridge having a steel slab will be referred to as a "steel slab bridge", a bridge having a concrete slab will be referred to as a "concrete slab bridge", and a bridge having a synthetic slab will be referred to as a "synthetic slab bridge".

The steel plates (same as the deck plate) that form the steel deck are the vertical ribs (sometimes called vertical beams) arranged parallel to the main girder and the vertical to the main girder (hereinafter, "bridge width direction"). It is stiffened by horizontal ribs (sometimes called cross beams) arranged in (referred to as). That is, the vertical ribs and the horizontal ribs are welded and connected to the lower surface of the steel plate, and the intersection between the vertical ribs and the horizontal ribs (hereinafter referred to as "rib intersection") is also welded and connected. Then, pavement such as asphalt is applied to the upper surface of the steel plate.
On the other hand, in the synthetic floor slab, concrete is laid on the upper surface of the steel plate forming the composite floor slab, and the steel plate may be stiffened by vertical ribs and horizontal ribs in the same manner as the steel slab. At this time, the vertical ribs and the horizontal ribs are buried in the concrete.

The vertical ribs are roughly classified into trapezoidal U ribs and the like that form a closed space, valve ribs and flat ribs that do not form a closed space, and the like. The U-rib is a steel material having a side surface corresponding to the hypotenuse of the trapezoid and a lower surface corresponding to the upper side of the trapezoid. Form a closed space of shape.
The lateral rib has a T-shaped cross section, one side edge (upper edge) of the web is welded and connected to the steel plate, and the other side edge (lower edge) is provided with a flange. Then, a trapezoidal notch portion through which the vertical rib can penetrate is formed in the web, and both side surfaces of the U rib are welded to the horizontal rib at the rib intersection (notch portion).

A "lower scallop" is provided at the innermost part of the notch. Therefore, the welding line between the U rib and the horizontal rib is formed between the steel plate (deck plate) and the lower scallop, and the welding line on one side surface side and the welding line on the other side surface side sandwich the lower scallop. Welded. That is, a gap is formed between the lower surface of the U rib and the innermost part of the notch, and the welding line between the U rib and the lateral rib is "welded end point (welding start end and welding end point are referred to as" welding end point "). "have.

On the other hand, the flat rib is a flat plate, and at this time, a rectangular slit into which the flat plate can be inserted is formed in the horizontal rib, and an "upper scallop" is provided at the mouth of the slit, and at the innermost part of the slit. A "lower scallop" is provided.
Then, in a state where the upper end edge of the flat rib is welded and connected to the steel plate, the flat rib penetrates into the slit of the horizontal rib, and one side surface of the flat rib is welded and connected to the horizontal rib at the rib intersection. A gap is formed between the other side surface and the lateral rib.
Therefore, the weld line between the flat rib and the lateral rib is formed between the upper scallop and the lower scallop on only one side surface, and has a weld end point. Further, in the upper scallop, the welding line between the flat rib and the horizontal rib is separated from the welding line between the flat rib and the steel plate, and is also separated from the welding line between the horizontal rib and the steel plate.

Since a complicated load (hereinafter referred to as "wheel load") by a traveling vehicle repeatedly acts on a steel plate, a complicated bending moment is repeatedly generated on a steel plate. At this time, the vertical ribs stiffen the steel plate in the bridge axis direction and mainly generate stress in the bridge axis direction, and the horizontal ribs stiffen the steel plate in the bridge width direction and mainly generate stress in the bridge width direction. Therefore, both the deformation of the vertical rib and the deformation of the horizontal rib are accumulated at the rib intersection to cause extremely complicated local deformation, and concentrated local stress is generated.
Further, the vertical ribs are further complicated in the concentration of local stress due to the form of the welded connection at the rib intersection as described above. For this reason, steel deck bridges tend to have fatigue cracks particularly at weld end points, and an invention for suppressing the occurrence of such fatigue cracks has been disclosed (see, for example, Patent Document 1).

JP 2013-245459 (pages 6-8, FIG. 5)

In the invention disclosed in Patent Document 1 (steel slab and a steel slab bridge provided with the steel slab), the steel slab has a U-rib and a trapezoidal notch in which the U-rib can penetrate are formed on the web. It has a horizontal rib and a lower scallop is continuously provided at the innermost part of the notch.
Further, a curved portion parallel to the side edge of the notch portion (corresponding to the hypotenuse of the trapezoid) is formed continuously at the innermost part of the notch portion (lower edge corresponding to the upper side of the trapezoid), and the notch portion is formed. A substantially strip-shaped narrow member is formed between a predetermined range on the back side and the curved portion.
Therefore, at the rib intersection, the U-rib is welded to the web of the horizontal rib on the mouth side of the notch and is welded to the narrow member on the back side of the notch, so that the weld line is a U-rib. Although it is continuous (overlapping) with the weld line between the steel plate and the steel plate, it has a weld end point facing the lower scallop at the lower end of the narrow member.
Then, since the narrow member (particularly the inner side) has lower rigidity than the web and is easily deformed, the stress concentration at the weld end point is relaxed, so that the occurrence of fatigue cracks at the weld end point is suppressed. There is.

However, the invention disclosed in Patent Document 1 has a problem that a weld crack is generated from the weld end point because a weld end point facing the lower scallop is formed at the rib intersection.
In addition, since a closed space is formed, single-sided welding is performed, so that the weld may not melt over the entire wall thickness, and there is a problem that fatigue cracks occur from the weld line between the U rib and the lateral rib.
Further, since the horizontal rib is welded to the main girder, there is a problem that the construction period becomes long at the time of replacement or new installation.

The present invention is to solve such a problem, and to provide a steel deck instant bridge capable of suppressing the occurrence of fatigue cracks from the weld line at the rib intersection and shortening the construction period.

(1) The steel deck instant bridge according to the present invention has a main girder arranged in the direction of the bridge axis and a steel deck panel installed on the main girder.
The steel deck panel includes a steel plate, vertical ribs in the bridge axis direction, and horizontal ribs in the direction perpendicular to the bridge axis direction.
The vertical rib is a rectangular flat plate, and the upper end surface of the vertical rib is welded and connected to the steel plate.
The horizontal rib is a steel material having a T-shaped cross section including a flat plate-shaped horizontal rib web and a flange below the horizontal rib provided at the lower end edge of the horizontal rib web, and a rectangular slit is formed in the horizontal rib web.
The vertical rib penetrates into the slit, both side surfaces and the lower end surfaces of the vertical rib are welded to the horizontal rib web at the intersection of the slit and the vertical rib, and the upper end surface of the horizontal rib web is the steel plate. Welded and connected to
The main girder is a steel material rolled into an H-shaped cross section having a flat plate-shaped main girder web and a main girder upper flange and a main girder lower flange provided at both ends of the main girder web, respectively. Provided with a web, a main girder stiffener connecting the main girder upper flange and the main girder lower flange,
The steel plate is connected to the main girder upper flange by bolts / nuts.
The lateral rib lower flange is connected to the main girder web via a split tee by bolts / nuts.
The lateral rib web is connected to the main girder stiffener by bolts / nuts via a splice plate.

(2) Further, the steel deck instant bridge according to the invention includes a flat plate-shaped support material web, a support material upper flange and a support material lower flange provided at both ends of the support material web, and the support material web. It has a steel deck support material provided with a support material stiffener connecting the support material upper flange and the support material lower flange, and has a steel deck support material.
Instead of connecting the steel plate to the main girder upper flange, the steel plate is connected to the support member upper flange by bolts / nuts, and the main girder upper flange is connected to the support member lower flange by bolts / nuts.
The lateral rib web is connected to the support material stiffener by bolts / nuts via a splice plate.
(3) Further, the welding start end and the welding end of the welding line connecting the vertical rib and the horizontal rib by welding are located on one side surface and the other side surface of the vertical rib, respectively.
(4) Further, a welding line for welding and connecting the vertical rib and the horizontal rib, a welding line for welding and connecting the vertical rib and the steel plate, and a welding line for welding and connecting the horizontal rib and the steel plate. Cross.

In the steel deck instant bridge according to the present invention, the vertical ribs are formed by a flat plate, and both side surfaces and the lower end surfaces of the vertical ribs that have penetrated the slits formed in the horizontal ribs are welded and connected to the horizontal ribs.
That is, since the lower end surface of the vertical rib and the innermost part of the slit are closed by the welding line and there is no gap corresponding to the lower scallop, the stress concentration due to the ring load generated in the relevant portion is alleviated and the stress concentration is relaxed from the relevant portion. The occurrence of fatigue cracks is suppressed and the life is extended.
Further, since the end points (welding start end and welding end) of the welding line connecting the vertical rib and the horizontal rib by welding are not located between the lower end surface of the vertical rib and the innermost part of the slit, fatigue cracks from the corresponding portion Occurrence is further suppressed.
Further, since the welding line between the vertical rib and the horizontal rib, the welding line between the vertical rib and the steel plate, and the welding line between the horizontal rib and the steel plate intersect at the mouth of the slit (same as the upper end surface of the vertical rib). , The gap corresponding to the upper scallop is not formed. Therefore, since the stress concentration due to the wheel load in the portion is relaxed, the occurrence of fatigue cracks from the portion is suppressed and the life is extended.
Further, the vertical rib is a flat plate and is welded to the horizontal rib and the steel plate on both sides of the flat plate (same as double-sided welding), so that the connection is sound.

In addition, since the main girder and the steel deck are connected by bolts / nuts via split tees and splice plates, installation is easy and construction is quick. Also, the removal work will be quicker.
In addition, since the steel deck support material is installed on the main girder, the degree of freedom of installation is increased. That is, even when a pre-standardized steel slab panel and a pre-standardized main girder are used, the height of the existing substructure can be adjusted by adjusting the height of the steel slab support material. The steel slab (the upper surface of the pavement provided on the steel slab panel) can be set to a desired height regardless of the height (the height including the bearing means of the pier).
Further, since the main girder is formed of rolled H-section steel, it becomes easy to standardize, and it becomes possible to reduce the manufacturing cost and the construction time. In other words, by adopting steel deck panels and rolled H-section steel, it can be expected to reduce the life cycle cost from manufacturing to maintenance by combining standard commercialization, design-less, and partial factory implementation of pavement. , Existing substructure can be diverted.

It is a perspective view which looked at the steel deck instant bridge which concerns on Embodiment 1 of this invention from diagonally above front and diagonally below. It is an enlarged perspective view which shows a part of the steel deck instant bridge shown in FIG. It is a perspective view which saw the member (steel slab panel) constituting the steel slab instant bridge shown in FIG. 1 from diagonally lower front and diagonally upward. It is a front view which shows a part (steel plate and vertical rib) of the member (steel slab panel) constituting the steel slab instant bridge shown in FIG. It is a front view which shows a part (horizontal rib) of the member (steel slab panel) constituting the steel slab instant bridge shown in FIG. FIG. 5 is an enlarged perspective view showing a part (rib intersection) of a member (steel slab panel) constituting the steel slab instant bridge shown in FIG. 1. FIG. 5 is a perspective view of a test material for testing the characteristics of the steel deck instant bridge shown in FIG. 1 as viewed from diagonally above and diagonally downward from the front. It is a front view which shows a part of the test material shown in FIG. 7. It is a front view which shows a part of the comparative material for comparison with the test material shown in FIG. 7. It is a bar graph which compares the total concentration stress of the test material and the comparative material for testing the characteristic of the steel deck instant bridge shown in FIG. It is a "load-loading frequency curve" showing the result of a fatigue test for testing the characteristics of the steel deck instant bridge shown in FIG.

[Embodiment 1]
Next, Embodiment 1 according to the present invention will be specifically described with reference to the drawings. The following drawings are schematically drawn, and the present invention is not limited to the drawn form and can be changed as appropriate.

(Steel floor slab instant bridge)
1 to 6 respectively explain the steel deck instant bridge according to the first embodiment of the present invention, FIG. 1 is a perspective view seen from diagonally above and diagonally downward from the front, and FIG. 2 is a perspective view thereof. A partially enlarged perspective view, FIG. 3 is a perspective view of the constituent members (steel slab panel) viewed diagonally upward from diagonally below the front, and FIG. 4 is one of the constituent members (steel slab panel). A front view showing a part (steel plate and vertical ribs), FIG. 5 is a front view showing a part (horizontal ribs) of a constituent member (steel slab panel), and FIG. 6 is one of the constituent members (steel slab panel). It is a perspective view which shows the part (rib intersection part) enlarged.

In FIGS. 1 and 2, the steel deck instant bridge 100 includes a main girder 40 installed in a bearing device installed on a pier (not shown), a steel slab support member 50 installed in the main girder 40, and a main girder. It has 40 and a steel slab panel 200 attached to a steel slab support 50.
The main girders 40 are arranged in four rows in the bridge width direction, and three steel deck panels 200 forming the steel deck slab are installed in the bridge width direction. However, the present invention is not limited to this. It can be in rows or any number. The longitudinal direction of the main girder 40 is the "bridge axis direction (Y direction)", the direction perpendicular to the bridge axis direction is the "bridge width direction (X direction)", and the direction perpendicular to the XY plane is "vertical". Direction (Z direction) ".

(Main girder)
The main girder 40 is a steel material rolled into an H-shaped cross section (referred to as “rolled H-shaped steel” in the present invention), and the main girder web 41 (located on the YZ plane) and the main girder web 41. The main girder upper flange 42a (located on the XY plane) and the main girder lower flange 42b (located on the XY plane) are provided on both side edges of the main girder. Further, a plurality of main girder stiffeners 43 (located on the XZ plane) connecting the main girder web 41, the main girder upper flange 42a, and the main girder lower flange 42b are provided at intervals in the longitudinal direction.

(Steel floor slab support material)
The steel deck support member 50 is a steel material having an H-shaped cross section, and the support member web 51 (located on the YZ plane) and the support member upper flange 52a (X) formed on both side edges of the support member web 51, respectively. It is provided with a −Y surface) and a support member lower flange 52b (located on the XY surface).
Further, a plurality of support material stiffeners 53 (located on the XX plane) connecting the support material web 51, the support material upper flange 52a, and the support material lower flange 52b are provided at intervals in the longitudinal direction. The steel deck support material 50 is formed by welding and joining steel plates to form an H-shaped cross section, but may be rolled H-shaped steel.

(Steel floor slab panel)
In FIG. 1, the steel deck panel 200 has a steel deck 10, a vertical rib 20 in the bridge axis direction, and a horizontal rib 30 in the bridge width direction (X direction). Since the factory-constructed pavement 12 is applied to the upper surface of the steel plate 11 constituting the steel deck 10 at the manufacturing factory and the on-site construction pavement 13 is applied at the construction site, the construction time is shortened. The pavement 12 may be carried out at the construction site.

(Vertical ribs that make up the steel deck panel)
In FIGS. 3 and 4, the vertical rib 20 is formed by a rectangular flat plate 21, and the upper end surface 21a of the flat plate is welded to the steel plate 11 (the weld line of such a welded connection is referred to as “W21”).
For convenience of explanation, the distance between the flat plate upper end surface 21a and the flat plate lower end surface 21b is "flat plate height H", and the distance between the flat plate side surface 21s and the flat plate side surface 21t (same as the thickness of the flat plate 21) is "flat plate thickness". T ”, one side surface is referred to as“ flat plate side surface 21s ”, and the other side surface is referred to as“ flat plate side surface 21t ”.

(Horizontal ribs that make up the steel deck panel)
In FIGS. 3 and 5, the horizontal ribs 30 are formed by a substantially rectangular horizontal rib web 31, a horizontal rib lower flange 32 provided on the horizontal rib lower end 31b of the horizontal rib web 31, and a horizontal rib upper end surface 31a to the horizontal rib lower end 31b. The slit 33 is provided so as to face the steel plate 11, and the upper end surface 31a of the lateral rib is welded to the steel plate 11 (the weld line of the welded connection is referred to as “W31”). The vertical rib 20 can penetrate into the slit 33. For convenience of explanation, the mouth of the slit 33 is the "slit upper end 33a", the innermost part is the "slit lower end edge 33b", one side edge is the "slit side edge 33s", and the other side surface is the "slit side edge". They are called "33t" respectively.
At the mouth of the slit 33, a C chamfer 34s is formed at the corner between the slit side edge 33s and the horizontal rib upper end surface 31a, and a C chamfer 34t is formed at the corner between the slit side edge 33t and the horizontal rib upper end surface 31a. ..
When the distance between the upper end 33a of the slit and the lower end edge 33b of the slit is referred to as "slit depth D", the slit depth D is slightly larger than the flat plate height H. Further, the distance between the slit side edge 33s and the slit side edge 33t (same as the width of the slit 33, hereinafter referred to as "slit width S") is slightly larger than the flat plate thickness H.

(Rib intersection of steel deck panel)
In FIGS. 3 and 6, the flat plate 21 enters the slit 33, and at the rib intersection, the flat plate lower end surface 21b is on the slit lower end edge 33b, the flat plate side surface 21s is on the slit side edge 33s, and the flat plate side surface 21t is on the slit side edge 33t. (The welding line of such a welding connection is referred to as "W23"). That is, the welding line W23 is "whole circumference welding" in the range excluding the upper end surface 21a of the flat plate. At this time, the welding end points of the welding line W23 (not shown) are not at the positions of the flat plate lower end surface 21b (same as the slit lower end edge 33b), but the flat plate side surface 21s (same as the slit side edge 33s) and the flat plate side surface 21t (slit side edge). Same as 33t).
Since the C chamfer 34s and the C chamfer 34t are as small as "C10", the welding line W21, the welding line W31, and the welding line W23 intersect (overlap) at the C chamfer 34s and the C chamfer 34t. ), The originally formed triangular gap is closed. Therefore, at the rib intersection, a gap corresponding to the upper scallop and a gap corresponding to the lower scallop are not formed.

(Effect of steel deck panel)
As described above, since the steel deck panel 200 does not form a gap corresponding to the upper scallop and a gap corresponding to the lower scallop at the rib intersection as in the conventional case, in particular, the lower end surface 21b of the flat plate of the welding line W23 ( The stress concentration at the position (same as the lower end edge 33b of the slit) is relaxed, and the occurrence of fatigue cracks from the portion is suppressed.
Further, since the end points (starting end and ending) of the welding line W23 do not exist at the position of the lower end surface 21b of the flat plate (same as the lower end edge 33b of the slit), the occurrence of fatigue cracks from that position is further suppressed.
Therefore, the life of the steel deck panel 200 is extended (this will be described in detail separately).

(Attachment of steel deck panel to main girder)
Again, in FIGS. 1 and 2, the steel deck support member 50 is placed on the main girder 40, and the main girder upper flange 42a and the support member lower flange 52b are connected by bolts / nuts 80. Then, the side edge portion of the steel plate 11 constituting the steel deck panel 200 is placed on the support member upper flange 52a, and both are connected by bolts / nuts 80.
Further, the lateral rib lower flange 32 of the lateral rib 30 constituting the steel deck panel 200 is connected to the main girder web 41 by a bolt / nut 80 via a split tee 60 and a splice plate 61.
Further, the lateral rib web 31 of the lateral rib 30 is connected to the main girder stiffener 43 by the bolt / nut 80 via the splice plate 74, and is connected to the support material stiffener 53 via the splice plate 75 by the bolt / nut 80. ing.

The horizontal rib lower flange 32 is connected to the splice plate 61, the splice plate 61 is connected to the split tee 60 having a T-shaped cross section, and the split tee 60 is connected to the main girder web 41. The splice plate 61 is removed, and the inner and outer surfaces of the lower flange 32 of the lateral rib are sandwiched by the split tee having an L-shaped cross section, and the split tee having an L-shaped cross section is used as the main girder web 41. May be connected by bolts / nuts 80.

(bolt and nut)
The bolt / nut 80 refers to a fastening means including a bolt penetrating a predetermined through hole (not shown) and a nut screwed into the bolt, and is accompanied by a washer and a slack stopper as necessary. The materials, shapes, and dimensions of the bolts and nuts forming the bolts / nuts 80 are not limited, and are appropriately selected according to the installation location. For example, if the bolt in the bolt / nut 80 connecting the steel plate 11 and the support member upper flange 52a is a "dish-shaped high-strength bolt", it is suitable for on-site construction pavement 13 on the upper surface of the steel plate 11.

(Effect of instant bridge on steel deck)
As described above, the steel deck instant bridge 100 has the steel deck panel 200, and the steel deck panel 200 suppresses the occurrence of fatigue cracks as described above, so that the maintainability is improved and the life is extended. To do. Further, since the steel deck panel 200 is connected to the main girder 40 and the steel deck support member 50 by bolts / nuts 80, welding is not required, so that the work is simplified and the construction time is shortened.
The above is the case where the steel deck support member 50 is provided, but the present invention is not limited to this, and the steel plate support member 50 is removed and the steel plate 11 is directly attached to the main girder upper flange 42a. They may be placed and both connected by bolts / nuts 80.

(Example of steel deck panel)
The steel deck panel 200 is manufactured to the dimensions shown below, and a plurality of steel deck panels 200 can be arranged side by side.
The steel plate 11 constituting the steel deck 10 has a length of 4500 mm in the bridge axis direction (Y direction), a length of 2560 mm in the bridge width direction (X direction), and a thickness (Z direction) of 16 mm.
The flat plate forming the vertical ribs 20 is a rectangular steel plate having a flat plate height H of 256 mm and a flat plate thickness T of 16 mm. And seven pieces are arranged at an interval of 320 mm in the bridge width direction (X direction).
The horizontal rib 30 has a distance from the upper end surface 31a of the horizontal rib to the lower surface of the lower flange 32 of the horizontal rib (hereinafter referred to as “horizontal rib height”) of 600 mm, and the thickness of the horizontal rib web 31 is 9 mm. The slits 33 are formed at seven positions at intervals of 330 mm, the slit depth D is 258 mm, and the slit width S is 20 mm.

Therefore, the vertical rib 20 can completely penetrate into the slit 33, between the flat plate lower end surface 21b and the slit lower end edge 33b, between the flat plate side surface 21s and the slit side edge 33s, and between the flat plate side surface 21t and the slit side edge 33t. It is designed to have a gap of 2 mm between them.
Since the machining accuracy has improved due to the development of machine tools (for example, NC laser machining machines), even if the value of the gap fluctuates due to manufacturing error, mounting error, etc., the design does not hinder the welding connection. It has become.
Then, a factory-constructed pavement 12 having a pavement thickness of 80 mm is provided in the manufacturing factory in a rectangular range excluding both side edges and both end edges of the upper surface of the steel plate 11. In addition, in the range excluding the factory-constructed pavement 12 (same for both side edges and both end edges), after the steel deck panel 200 is attached to the main girder 40 at the construction site, the on-site construction pavement 13 having a pavement thickness of 80 mm is completed. Is provided (see FIG. 1). The factory construction pavement 12 may be provided at the construction site.

(Example of main girder)
The main girder 40 is manufactured by integrating the span distances into three levels of 10 m, 15 m, and 20 m. That is, when the span distance is 10 m, it is a rolled H-section steel having a web height of 600 mm, a flange width of 300 mm, a web thickness of 14 mm, and a flange thickness of 28 mm. When the span distance is 15 m, it is a rolled H-section steel having a web height of 850 mm, a flange width of 300 mm, a web thickness of 19 mm, and a flange thickness of 32 mm. Further, when the span distance is 20 m, it is a rolled H-section steel having a web height of 1000 mm, a flange width of 300 mm, a web thickness of 19 mm, and a flange thickness of 28 mm. The material is SM400 or SM490, but the material is not limited to this.

(Test material)
7 to 9 respectively explain the steel deck instant bridge according to the first embodiment of the present invention, and FIG. 7 shows a test material for testing its characteristics from diagonally above the front to diagonally downward. 8 is a front view showing a part thereof, and FIG. 9 is a front view showing a part of a comparative material for comparison.
The same parts as the steel deck panel 200 are designated by the same reference numerals and the description thereof will be omitted. In addition, for ease of understanding, the member dimensions, the gaps between the members, and the width of the weld line are exaggerated.

In FIGS. 7 and 8, in the test material 300, the steel deck panel 200 is directly installed on the pair of main girders 40, the main girder upper flange 42a and the steel deck support material 50 of the main girder 40 are removed, and the steel plate 11 Is the same as the one directly welded to the main girder web 41 and the main girder stiffener 43.
The lateral rib lower flange 32 is welded directly to the main girder web 41 at the position of the main girder stiffener 43, respectively, without the splice plate 61 and the split tee 60, and the lateral rib web 31 not through the splice plate 74. ing.
At this time, the main girder 40 has a length (distance in the bridge axis direction) of 5000 mm and a girder height of 1000 mm, and the main girder 40 is provided with four main girder stiffeners 43 at equal intervals in the bridge axis direction. Further, the main girders 40 are arranged with an interval (distance in the bridge width direction) of 2000 mm.
The steel deck panel 200 includes 6 vertical ribs 20 in the bridge width direction and 4 horizontal ribs 30 in the bridge axis direction. Then, the dimensions and the like of the rib intersection are the same as the values of the above-described embodiment.

(Comparison material)
In FIG. 9, the comparative material 900 has a steel plate 11, a vertical rib 20 in the bridge axis direction, and a comparative horizontal rib 90 in the bridge width direction, although the shape of the rib intersection is different from that of the test material 300. The shape and dimensions of the portion excluding the above are the same as those of the test material 300. That is, it differs from the slit 33 formed in the test material 300 in that the comparative slit 93 is formed in the comparative material 900 and the comparative scallop 95 is formed in the innermost part of the comparative slit 93. The differences between the two will be described below.

(Horizontal rib of comparison material)
The comparison lateral rib 90 includes a comparison web 91 which is a rectangular flat plate, and a comparison slit 93 formed from the comparison upper end 91a to the comparison lower end 91b of the comparison web 91, and the comparison scallop 95 is located at the innermost part of the comparison slit 93. It is formed. The vertical rib 20 can penetrate into the comparison slit 93, and the width of the comparison slit 93 is larger than the flat plate thickness T. Further, a comparative C chamfer 94s is formed at the mouth of the comparative slit 93.
For convenience of explanation, the mouth of the comparison slit 93 is the "comparison slit upper end 93a", the innermost part is the "comparison slit lower end edge 93b", one side edge is the "comparison slit side edge 93s", and the other side surface. It is referred to as "comparative slit side edge 93t". The distance between the upper end 93a of the comparison slit and the lower end edge 93b of the comparison slit is larger than the flat plate height H.
The comparative scallop 95 has a substantially circular shape in contact with the lower end edge 93b of the comparative slit, and forms a gap having a distance larger than the distance between the comparative slit side edge 93s and the comparative slit side edge 93t.

(Rib intersection of comparative material)
The upper end surface of the flat plate of the vertical rib 20 is connected to the steel plate 11 by the welding line W21, the comparison upper end 91a of the comparison web 91 is connected to the steel plate 11 by the welding line W91, and the flat plate 21 penetrates into the comparison slit 93.
At this time, a gap is formed between the lower end surface 21b of the flat plate and the lower end edge 93b of the comparison slit, and the side surface 21s of the flat plate is welded and connected in a range excluding the comparison scallop 95 of the side edge 93s of the comparison slit (welding of such a welding connection). The line is called "W93"). On the other hand, the flat plate side surfaces 21s face the comparative slit side edge 93t and are separated from each other without being welded to each other.
At this time, the upper end of the welding line W93 overlaps the welding line W21 and the welding line W91 and closes the comparison C chamfer 94s, but the lower end of the welding line W93 is located on the comparison scallop 95 and is compared. Does not block the scallop 95. That is, the welding end point of the welding line W93 is located at the comparative scallop 95. Either the welding line W91 or the welding line W93 may be formed first.

(FEA)
Prior to the fatigue test, (a) the critical loading position was confirmed by FEA (finite element method analysis), and then (b) fatigue resistance details were examined. The support condition is four-point support that supports both ends of the pair of main girders 40, respectively.

(Critical load position)
Concentrated tensile stress and concentrated compressive stress are generated in the vertical ribs 20 of the steel deck panel 200 depending on the traveling position of the vehicle. That is, when the concentrated stress generated in the vertical rib (temporarily referred to as "R1") whose loading position has been changed is obtained and the concentrated stress for each loading position is compared, it is referred to as the loading position (hereinafter referred to as "maximum tensile loading position"). ) The maximum concentrated tensile stress (σ1 +) is generated when loaded on F1, and the maximum concentrated compressive stress (σ1-) is generated when loaded on the loading position (hereinafter referred to as “maximum compression loading position”) Q1. You can see that. Then, the sum of the absolute values of the maximum concentrated tensile stress (σ1 +) and the maximum concentrated compressive stress (σ1-) for the vertical rib R1 is defined as the “total concentrated stress (σ1 ±)”.
Similarly, for each of the other vertical ribs R2, R3 ..., The maximum tensile load positions F2, F3 ..., the maximum compression load positions Q2, Q3 ..., And the total concentrated stress σ2 ±, σ3 ± ...・ Ask for.
Therefore, the vertical rib Rj corresponding to the largest value of the obtained total concentrated stress σ1 ±, σ2 ±, σ3 ± ... Corresponding to the total concentrated stress σj ± is defined as the “vertical rib of interest”, and the vertical rib Rj is defined. The maximum tensile loading position Fj is referred to as the "critical loading position" of the steel deck panel 200.

(Sum of concentrated stress)
FIG. 10 is a bar graph for comparing the total concentrated stresses of the test material and the comparative material for testing the characteristics of the steel deck instant bridge according to the first embodiment of the present invention. The concentrated tensile stress is indicated by a downward-sloping diagonal line, and the absolute value of the concentrated compressive stress is indicated by an upward-sloping diagonal line.
In FIG. 10, in the test material 300, when a load of 100 kN is applied to the maximum tensile load position Fj for the vertical rib Rj of interest, a concentrated tensile stress (σj +) of 25 N ^{/ mm 2 is generated at the maximum compressive load position Qj.} when the loading of 100 kN, 55N / mm ² concentration compressive stress (σj-) is generated, stress concentration sum (.SIGMA.j ±) is set to 80 N / mm ^2.
On the other hand, for the comparative material 900, when the vertical ribs of interest are specified in the same manner as the test material 300 and 100 kN is loaded at the maximum tensile loading position and the maximum compression loading position, the concentrated tensile stress is generated at the vertical ribs of interest. 92N / mm ^2, concentrated compressive stress 85N / mm ² occurs, stress concentration sum is in 177N / mm ^2.
That is, the total concentrated stress of the test material 300 is 58% lower than that of the comparative material 900, and in particular, the concentrated tensile stress is 73% lower. Therefore, it was confirmed that the total concentrated stress was significantly reduced because the test material 300 did not have a gap corresponding to the lower scallop.

(Fatigue test)
FIG. 11 is a “load-loading frequency curve” showing the result of a fatigue test for testing the characteristics of the steel deck instant bridge according to the first embodiment of the present invention. The vertical axis represents the repeated load loaded at the critical loading position, and the horizontal axis represents the number of repetitions (described as “fatigue life” in FIG. 11).
In FIG. 11, when a load of 200 kN is repeatedly loaded at the critical loading position of the test material 300 and the critical loading position of the comparative material 900, fatigue cracks do not occur in the test material 300 even after repeating about 70 million times. (Indicated by a black square with a black arrow in the diagonally upward right direction), the comparative material 900 has fatigue cracks generated by repeating about 2 million times (indicated by a white square).
Further, even when the test material 300 was repeatedly loaded with a load of 340 kN about 1 million times, fatigue cracks did not occur (indicated by a black square with a black arrow in the diagonally upward right direction).
The diagonal line in the figure indicates "10 million times in terms of T load".
From the above, it was confirmed that the test material 300 has excellent fatigue durability. That is, in the test material 300, since the vertical ribs 20 and the horizontal ribs 30 are welded and connected over the entire circumference at the rib intersection and do not have a gap corresponding to the lower scallop, fatigue cracks from the weld line 23 at the position are present. Is suppressed.

The present invention has been described above with respect to the steel deck instant bridge based on the first embodiment, but these are examples, and various modifications are possible, and such modifications are also within the scope of the present invention. That is to be understood by those skilled in the art.

Since the steel deck instant bridge according to the present invention suppresses the occurrence of fatigue cracks from the weld line and can be constructed quickly, it is not limited to small-scale bridges, but is widely used for various bridges. Can be done.

10: Steel floor slab 11: Steel plate 12: Factory-constructed pavement 13: On-site construction pavement 20: Vertical rib 21: Flat plate 21a: Flat plate upper end surface 21b: Flat plate lower end surface 21s: Flat plate side surface 21t: Flat plate side surface 30: Horizontal rib 31: Horizontal Rib web 31a: Horizontal rib upper end surface 31b: Horizontal rib lower end 32: Horizontal rib lower flange 33: Slit 33a: Slit upper end 33b: Slit lower end edge 33s: Slit side edge 33t: Slit side edge 34s: C chamfer 34t: C chamfer 40: Main girder 41: Main girder web 42a: Main girder upper flange 42b: Main girder lower flange 43: Main girder stiffener 50: Steel deck support material 51: Support material web 52a: Support material upper flange 52b: Support material lower flange 53: Support material Stiffener 60: Split tee 61: Splice plate 74: Splice plate 75: Splice plate 80: Bolt / nut 90: Comparison lateral rib 91: Comparison web 91a: Comparison upper end surface 91b: Comparison lower end 92: Comparison lower flange 93: Comparison slit 93a: Comparison slit upper end 93b: Comparison slit lower edge 93s: Comparison slit side edge 93t: Comparison slit side edge 94s: Comparison C chamfer 95: Comparison scallop 100: Steel slab instant bridge 200: Steel slab panel 300: Test Material 900: Comparative material W21: Welding line W31: Welding line W23: Welding line W91: Welding line W93: Welding line

Claims (4)

It has a main girder arranged in the direction of the bridge axis and a steel deck panel installed on the main girder.
The steel deck panel includes a steel plate, vertical ribs in the bridge axis direction, and horizontal ribs in the direction perpendicular to the bridge axis direction.
The vertical rib is a rectangular flat plate, and the upper end surface of the vertical rib is welded and connected to the steel plate.
The horizontal rib is a steel material having a T-shaped cross section including a flat plate-shaped horizontal rib web and a flange below the horizontal rib provided at the lower end edge of the horizontal rib web, and a rectangular slit is formed in the horizontal rib web.
The vertical rib penetrates into the slit, both side surfaces and the lower end surfaces of the vertical rib are welded to the horizontal rib web at the intersection of the slit and the vertical rib, and the upper end surface of the horizontal rib web is the steel plate. Welded and connected to
The main girder is a steel material rolled into an H-shaped cross section having a flat plate-shaped main girder web and a main girder upper flange and a main girder lower flange provided at both ends of the main girder web, respectively. Provided with a web, a main girder stiffener connecting the main girder upper flange and the main girder lower flange,
The steel plate is connected to the main girder upper flange by bolts / nuts.
The lateral rib lower flange is connected to the main girder web via a split tee by bolts / nuts.
The lateral rib web is a steel deck instant bridge connected to the main girder stiffener by bolts / nuts via a splice plate. A support material that connects the flat support material web, the support material upper flange and the support material lower flange provided at both ends of the support material web, and the support material web, the support material upper flange, and the support material lower flange, respectively. Has a steel deck support with a stiffener,
Instead of connecting the steel plate to the main girder upper flange, the steel plate is connected to the support member upper flange by bolts / nuts, and the main girder upper flange is connected to the support member lower flange by bolts / nuts.
The steel deck instant bridge according to claim 1, wherein the lateral rib web is connected to the support material stiffener by bolts / nuts via a splice plate. The steel according to claim 1 or 2, wherein the welding start end and welding end of the welding line connecting the vertical rib and the horizontal rib by welding are located on one side surface and the other side surface of the vertical rib, respectively. Floor slab instant bridge. The welding line that welds and connects the vertical rib and the horizontal rib, the welding line that welds and connects the vertical rib and the steel plate, and the welding line that welds and connects the horizontal rib and the steel plate intersect. The steel plate instant bridge according to any one of claims 1 to 3.

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