JP2008280753A - Steel floor slab and method of producing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel floor slab whose horizontal ribs can be spaced apart by large spans, while preventing fatigue cracks at welded parts, and minimizing cost increases, and a method of manufacturing the steel floor slab. <P>SOLUTION: A plurality of cutouts 3C are formed in each horizontal rib 3, and the webs 4A of vertical ribs 4 are passed through the cutouts 3C, so that the horizontal ribs 3 can be produced continuously on one steel floor slab, and so that the webs 4A of the vertical ribs 4 can also be produced continuously without the vertical ribs 4 being cut at intersections with the horizontal ribs 3. The cutouts 3C in the horizontal ribs 3 are inserted from cutouts 4C cut in the flanges 4B of the vertical ribs 4, and the webs 3A, 4A of the horizontal ribs 3 and the vertical ribs 4 are welded and integrated together, whereby the man hours, the number of welded portions, and the welding length required for production can be reduced and manufacturing costs can be reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steel deck and a method for manufacturing a steel deck, and more specifically, a plurality of horizontal ribs supported by a main girder, a plurality of vertical ribs supported by crossing the horizontal ribs, and the horizontal ribs. The present invention relates to a steel deck slab comprising a rib and a deck plate fixed to the upper side of a longitudinal rib by welding and used as a roadbed support structure in a road bridge or the like, and a method for manufacturing the same.

Conventionally, as a structure of steel floor slabs used for road bridges, etc., a notch is provided in a horizontal rib (horizontal girder), and a vertical rib is inserted into this notch to cross the horizontal rib and the vertical rib. In general, the horizontal rib and the vertical rib are welded and joined along the notch at the portion, and the deck plate is welded and fixed to the upper side of the horizontal rib and the vertical rib (see Chapter 5 of Non-Patent Document 1). .
Vertical ribs used in such steel slabs include U-shaped U-shaped ribs, flat plate-like ribs extending vertically, and a cross-sectional valve plate having an enlarged portion at the lower end of the plate extending vertically There are ribs (valve ribs) and the like, and the notch shape and welding position of the horizontal rib are defined according to the cross-sectional shape of these vertical ribs. That is, when the vertical rib is a U-rib, a pair of side end edges along the left and right side surfaces of the U-rib and a lower end edge along the lower surface of the U-rib have a notch shape that is continuous with scallops. The pair of side edge portions and the left and right side surfaces of the U rib are joined by single-sided fillet welding. On the other hand, in the case of flat ribs and valve ribs, a notch shape that extends vertically and has a scallop at the lower end and has a longitudinal groove shape, and has a width dimension through which the flat plate portion of the flat plate rib and the enlarged portion of the valve rib can be inserted. Thus, one side edge portion of the notch and the flat plate side surface of the flat plate rib or valve rib are joined by single-sided fillet welding. In Non-Patent Document 1, the target lateral rib interval (span) is 2.5 m or less, and those whose span exceeds 3 m are out of the target range.

On the other hand, as a structure of a steel slab, one using a CT section steel having an inverted T-shaped cross section in a longitudinal rib has been proposed (see Patent Document 1).
In the steel slab described in Patent Document 1, CT shape steel as vertical rib is placed and supported on the upper surface of H shape steel as horizontal rib installed on the main girder, and the upper edge of the web of this CT shape steel is supported. And a deck plate (steel plate having a thickness of 16 mm or more) are joined by double-sided fillet welding. This steel slab structure was devised for ease of construction and shortening the construction period when replacing road bridges, etc. CT section steel (vertical rib) is used for H section steel (lateral rib). Since it mounts, it has the fault that the height dimension of the whole steel deck will become large. On the other hand, in order to keep the height dimension of the entire steel slab below a predetermined dimension, the member height dimension of the transverse ribs and longitudinal ribs is reduced, and there is a disadvantage that the transverse rib interval cannot be widened due to the limit of the member strength. . Therefore, it is conceivable to use a CT shape steel having an inverted T-shaped cross section for the transverse rib, and weld the longitudinal rib to the web of this CT shape steel. In this case, the interval dimension ( Longitudinal ribs having lengths corresponding to the span) are prepared, and both longitudinal ends of the longitudinal ribs are welded to the web side surfaces of the pair of transverse ribs.

By the way, when a vehicle passes on a roadbed (on a deck plate) such as a road bridge, it occurs at the joint between the horizontal rib and the vertical rib due to the relationship of the load position (front wheel and rear wheel positions) with respect to the horizontal rib. Studies on stress have been made (see Fig. 26, Fig. 27, etc. in Non-Patent Document 2). According to this document, it is disclosed that the stress generated at the joint between the horizontal rib and the vertical rib increases as the load position moves away from the horizontal rib and becomes maximum near the center between the horizontal ribs. However, the research data described in Non-Patent Document 2 has an interval between adjacent lateral ribs (span) of 2.75 m, and does not disclose data when the span exceeds 3 m.
In addition, there has been a report on the investigation of existing road bridges for fatigue cracks that occur in welded joints such as deck plates, vertical ribs, and horizontal ribs due to dynamic loads from wheels acting on steel decks ( (See FIG. 1 and Table 2 of Non-Patent Document 3). According to this document, fatigue cracks are observed at the welded portion between the longitudinal rib and the deck plate, the butt welded portion between the longitudinal ribs, the intersecting portion between the longitudinal rib and the transverse rib, and in particular, the longitudinal rib ( It is disclosed that many fatigue cracks are observed at the intersections between U ribs and valve ribs) and lateral ribs.

Japanese Patent Laid-Open No. 11-50416 Fatigue design guidelines for steel road bridges (Japan Road Association) issued in March 2002 INTERNATIONAL INSTITUTE OF WELDING XIII-1973-03, “Identification of the cause of fatigue damage in an orthotropic steel bridge deck structure with box girder” (S.Suganuma and others.) Japan Society of Civil Engineers 61st Annual Lecture (September 2006), pages 1067-1068, "Fatigue damage report of steel slab on Hanshin Expressway" (Takada, et al.)

As described in Non-Patent Document 2 (see Fig. 22 etc. of the same document), when a vehicle travels on a deck plate of a steel deck on a road bridge, the deck plate is subjected to a dynamic load acting on the deck plate. The deformation of the vertical rib (U rib) and the horizontal rib is repeated. When subjected to such repeated deformation, there is a high possibility that fatigue cracks are generated in the welded portion between the deck plate and the vertical rib or the horizontal rib, and the welded portion between the vertical rib and the horizontal rib. And when the vertical rib is comprised from U rib, since it can weld to a deck plate only from the outer side of this U rib, the fatigue strength by the side of a root will become low.
Further, according to Non-Patent Document 2, since the stress generated at the joint between the horizontal rib and the vertical rib is maximized when the load position is near the center between the horizontal ribs, the wider the horizontal rib interval, The stress generated at the joint between the horizontal rib and the vertical rib increases, and the possibility of fatigue cracks occurring at the weld at the joint position is further increased.
U ribs used as conventional vertical ribs can be considered as a method for reducing the stress generated at the joint between the horizontal ribs and the vertical ribs, although the height of the vertical ribs and the horizontal ribs can be increased. Further, the manufacturing size of the plate thickness and member height dimension of the flat plate rib and the valve rib is limited. In particular, the flat size of the flat plate rib cannot be increased because the protrusion length of the free end is limited to prevent buckling. Therefore, it is difficult to increase the lateral rib interval beyond 2.5 m defined in Non-Patent Document 1.

On the other hand, based on the steel slab of Patent Document 1, if the structure in which both longitudinal ends of the longitudinal rib are welded to the side surface (web) of the lateral rib is employed, the following problems arise.
That is, the vertical ribs are cut for each span, which is the interval dimension of the horizontal ribs, and both ends of the vertical ribs are welded to the side surfaces of the horizontal ribs. Since the number becomes large, the number of members and the processing effort increase, and the manufacturing cost increases significantly. Furthermore, since these are welded in a state in which both end portions of the vertical rib are butted against the side surfaces of the horizontal rib, it becomes difficult to ensure the welding accuracy of the welded portion, which is likely to cause a decrease in fatigue strength. And since the number of places of such a welding part is enormous, possibility that a welding defect will generate | occur | produce will also increase and a fatigue crack will become easy to generate | occur | produce in a welding part also from this point.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a steel deck and a method for manufacturing a steel deck that can prevent a fatigue crack in a weld and minimize the increase in cost and increase the span between transverse ribs. .

  The steel deck according to claim 1 of the present invention includes a plurality of horizontal ribs supported by the main girder, a plurality of vertical ribs supported by crossing the horizontal ribs, and the horizontal ribs and the vertical ribs. A steel slab comprising a deck plate welded and fixed to the upper side, wherein the lateral rib has at least a web extending vertically, and the web has a plurality of notches that open upward and extend downward. The vertical rib has a substantially inverted T-shaped or L-shaped cross section from a vertically extending web and a flange continuous to the lower end of the web, and a position corresponding to the notch of the horizontal rib. The flanges are cut and formed, and the webs of the horizontal ribs and the longitudinal ribs are welded together along the notches in a state where the webs of the longitudinal ribs are inserted into the notches of the lateral ribs. It is characterized by being.

According to the present invention as described above, a plurality of notches are formed in the horizontal ribs, and the vertical ribs are inserted into these notches, so that the horizontal rib can be manufactured through a single piece. It is possible to manufacture through a web of vertical ribs without being cut at the intersection with. And the vertical rib which notched the flange was inserted in the notch of the horizontal rib, and it mutually crossed, and it can join together by welding each other's webs in this intersection, and the man-hour and number of welding locations ( (Welding length) can be reduced, and an increase in the number of members can be suppressed.
Further, by notching the flange of the vertical rib, the width dimension of the notch provided in the horizontal rib can be set regardless of the flange width of the vertical rib. Therefore, by setting the width dimension of the notch of the lateral rib to the minimum dimension necessary for inserting the web of the longitudinal rib, it is possible to reduce the generated stress in the welded portion between the lateral rib and the deck plate. . Furthermore, the fatigue damage in the welding part of a vertical rib and a deck plate can also be prevented by joining the web upper end edge of a vertical rib and a deck plate by double-sided fillet welding.
Further, by using a steel material having a substantially inverted T-shaped or substantially L-shaped cross section as the vertical rib, there is no restriction on the height of members such as conventional U ribs, flat ribs, valve ribs, etc. By appropriately setting the height dimension, it is possible to secure the welded joint length with the lateral rib, and it is possible to prevent fatigue damage at the welded portion between the longitudinal rib and the lateral rib. Furthermore, by increasing the height dimension of the vertical ribs, the distance between the horizontal ribs can be lengthened, and by increasing the span between the horizontal ribs, the number of members can be reduced, and the welding location can be reduced. By reducing this, the possibility of occurrence of fatigue cracks can be reduced.

At this time, in the steel slab of the present invention, it is preferable that the interval between the lateral ribs is set in a range of 3 m or more and 8 m or less.
Here, the distance between the horizontal ribs (the span of the horizontal ribs) is set to 8 m or less because the distance between the front and rear wheels of a large vehicle is about 8 m, so both the front and rear wheels are located within one span of the horizontal ribs. Under such conditions, the stresses generated in the transverse ribs, the longitudinal ribs, the deck plate, and their welded joints are significantly larger than those reported in Non-Patent Document 2 and the like. The above-described effects of the present invention can be obtained without any deviation.
Furthermore, in the steel slab of the present invention, it is preferable that the width dimension of the notch of the horizontal rib is set smaller than the width dimension of the flange of the vertical rib.
Further, in the steel slab of the present invention, a wide scallop having a larger width dimension than the flange of the vertical rib is formed at the lower end portion of the notch of the horizontal rib, and the notch of the vertical rib notched is formed. The flanges may be connected to each other through an attachment plate inserted through the scallop.
Furthermore, in the steel slab of the present invention, the web of the horizontal rib and the flange of the vertical rib may be joined via an attachment plate.
If the flanges of the longitudinal ribs or the webs of the lateral ribs and the flanges of the longitudinal ribs are connected to each other through the attachment plate in this way, the stress generated in the longitudinal ribs and the transverse ribs is dispersed by the attachment plate, and the welds The fatigue life of can be improved. Here, the joining of the longitudinal ribs or the transverse ribs and the accessory plate may be by welding or by bolt-nut joining.

On the other hand, the method for producing a steel slab according to claim 6 of the present invention includes a plurality of horizontal ribs supported by the main girder, a plurality of vertical ribs supported by crossing the horizontal ribs, and the horizontal ribs. A method of manufacturing a steel slab comprising a rib and a deck plate welded and fixed to the upper side of the vertical rib, wherein the horizontal rib has at least a web extending vertically, and the vertical rib is a web extending vertically And a flange continuous with the lower end of the web, each having a substantially inverted T-shaped or substantially L-shaped cross section, each having a plurality of openings that open upward in the web of the lateral rib and extend downward. A notch is formed, and a flange of the longitudinal rib is cut out at a position corresponding to the notch of the transverse rib, and then the web of the longitudinal rib is inserted into the notch of the transverse rib, and the transverse rib and the longitudinal rib are inserted. Ribbed webs in the notch Characterized by welding I.
According to such a configuration, as described above, it is possible to reduce the number of man-hours and the number of welds (welding length) required for assembling the horizontal ribs and the vertical ribs, and to weld the vertical ribs and the horizontal ribs. In addition, it is possible to prevent fatigue damage in the welded portion between the vertical rib and the horizontal rib and the deck plate.

In this case, in the method for producing a steel slab of the present invention, when forming the notch of the horizontal rib, a wide scallop having a width dimension larger than the flange of the vertical rib is formed at the lower end of the notch. Preferably, the web of the vertical rib is inserted into the notch of the horizontal rib, and the flanges of the notched vertical rib are connected to each other via an attachment plate inserted into the scallop.
Further, in the method for manufacturing a steel slab according to the present invention, the web of the vertical rib is inserted into the notch of the horizontal rib, and then the web of the horizontal rib and the flange of the vertical rib are joined via an attachment plate. May be.
According to such a configuration, the stress generated in the welded portion between the vertical rib and the horizontal rib, the welded portion between the vertical rib and the horizontal rib and the deck plate, and the like can be dispersed by the attachment plate. The fatigue life can be improved.

  According to the steel slab and the manufacturing method of the steel slab of the present invention as described above, fatigue cracks are prevented in the welded portion between the transverse rib and the longitudinal rib and the deck plate and the welded portion between the longitudinal rib and the transverse rib. In addition to improving the fatigue life, it is possible to increase the span between the horizontal ribs by setting the vertical height of the member height of the vertical ribs, thereby reducing the number of members and manufacturing man-hours, thereby reducing the cost increase. be able to.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a part of a road bridge using a steel deck 1 according to an embodiment of the present invention. In FIG. 1, the road bridge is composed of a substructure consisting of a foundation and a pillar (not shown), a steel main girder 2 installed between the pillars, and an intermediate steel floor supported between the pair of main girder 2. A plate 1 and a cantilevered steel floor plate 1 supported on both sides of the main girder 2 are provided. The steel deck 1 includes a plurality of horizontal ribs 3 supported by the main girder 2, a plurality of vertical ribs 4 supported so as to intersect the horizontal ribs 3, and the horizontal ribs 3 and the vertical ribs 4. The deck plate 5 is fixed to the upper side by welding.

FIG. 2 is a perspective view showing a state before assembly of the horizontal rib 3 and the vertical rib 4 in the steel deck 1. FIG. 3 is a perspective view showing a state in which the horizontal rib 3 and the vertical rib 4 are integrated. FIG. 4 is a cross-sectional view of the steel deck 1 viewed from the side of the vertical rib 4.
2 and 3, the horizontal rib 3 of the steel slab 1 is formed in a substantially inverted T shape having a web 3A extending vertically and a flange 3B integrated with the lower end of the web 3A. The web 3A of the lateral rib 3 is formed with a plurality of cutouts 3C that open upward and extend downward. Further, the vertical rib 4 is formed to have a substantially inverted T-shaped (or substantially L-shaped) cross section from a web 4A extending vertically and a flange 4B continuous to the lower end portion of the web 4A. The flange 4B of the vertical rib 4 is cut out at a position corresponding to the cutout 3C of the horizontal rib 3, and is divided into left and right sides with the cutout portion 4C interposed therebetween.

  The vertical rib 4 has the web 4A inserted into the notch 3C of the horizontal rib 3 from the position of the notch 4C, and the web 3A and 4A of the horizontal rib 3 and the vertical rib 4 are notched in this inserted state. Single-sided fillet welding is performed along 3C (welded portion W1), and the transverse rib 3 and the longitudinal rib 4 are integrated by this welding joint. Further, as shown in FIG. 4, the upper edges of the webs 3A, 4A of the horizontal rib 3 and the vertical rib 4 and the bottom surface of the deck plate 5 are welded on both sides (welded portions W2, W3). The rib 3 and the vertical rib 4 and the deck plate 5 are integrated.

  The notch 3C of the horizontal rib 3 has a width dimension that is larger than the plate thickness of the web 4A of the vertical rib 4 by a predetermined dimension (for example, 15 to 35 mm) and sufficiently smaller than the width dimension of the flange 4B of the vertical rib 4. It has a groove shape. And the scallop 3D is formed in the lower end part of the notch 3C. The vertical rib 4 and the horizontal rib 3 are such that one side surface of the web 4A of the vertical rib 4 is close to one end edge of the notch 3C, and the other side surface of the web 4A is the other end edge of the notch 3C. The side surface of the web 4A of the vertical rib 4 and the web 3A of the horizontal rib 3 are welded together along one edge of the cutout 3C in a state of being approximately the same distance as the predetermined dimension.

  As an assembly procedure of such a steel floor slab 1, first, as shown in FIG. 2, a plurality of notches 3C are formed in the web 3A of the lateral rib 3 and the flange 4B of the longitudinal rib 4 is notched. The notch 4C is formed. Next, the plurality of vertical ribs 4 with the flange 4B facing up are positioned on a deck plate 5 installed in a multi-electrode welding apparatus (not shown), and the vertical ribs are used by using a plurality of welding electrodes (torches) of the multi-electrode welding apparatus. 4 4A upper end edge and the deck plate 5 are joined by double-sided fillet welding (welded portion W3). Next, the horizontal rib 3 with the notch 3C facing downward is suspended from above the vertical rib 4 and the notch 3C is inserted from the notch 4C of the vertical rib 4. At this time, the width dimension of the notch 3C is set larger than the plate thickness of the web 4A of the vertical rib 4 by the predetermined dimension, so that the notch 3C of the horizontal rib 3 and the web 4A of the vertical rib 4 interfere with each other. Can be avoided, and the horizontal rib 3 can be set smoothly. After positioning the vertical rib 4 and the horizontal rib 3 as described above, the web 3A upper edge of the horizontal rib 3 and the deck plate 5 are welded to both sides by using a multi-electrode welding apparatus (welded portion W2). 3), the welded portion W1 is welded to join the horizontal rib 3 and the vertical rib 4 as shown in FIG.

  According to the steel plate 1 described above, a plurality of cutouts 3C are formed in the horizontal ribs 3, and the web 4A of the vertical ribs 4 is inserted into these cutouts 3C, so that a single piece of the horizontal rib 3 can be passed through. The vertical rib 4 can be manufactured through the web 4 </ b> A of the vertical rib 4 without being cut at the intersection with the horizontal rib 3. And the notch 3C of the horizontal rib 3 is inserted from the notch part 4C which notched the flange 4B of the vertical rib 4, and the mutual webs 3A and 4A of the horizontal rib 3 and the vertical rib 4 are welded and integrated. Thus, the man-hours required for production and the number of welding points (welding length) can be reduced.

  In addition, since the flange 3B of the vertical rib 4 is cut out, the width dimension of the cutout 3C of the horizontal rib 3 is kept to the minimum while ensuring the clearance during installation while inserting the web 4A of the vertical rib 4 Can be set to dimensions. Accordingly, the width of the portion of the lateral rib 3 that is not welded to the upper end edge of the web 3A and the deck plate 5 can be minimized to ensure the welding length, and fatigue damage at the welded portion between the lateral rib 3 and the deck plate 5 can be prevented. . Furthermore, by joining the web 3A, 4A upper end edge of the horizontal rib 3 and the vertical rib 4 and the deck plate 5 by double-sided fillet welding, fatigue damage in the welded portions W2, W3 can be prevented.

  Further, by using a steel material having a substantially inverted T-shaped or substantially L-shaped cross section as the vertical rib 4, there is no restriction on the height of members such as conventional U ribs, flat ribs, valve ribs, etc. By setting 4 to a large height dimension, the length dimension of the welded portion W1 can be sufficiently secured to prevent fatigue damage, and the distance dimension (span) between the lateral ribs 3 can be increased. it can. By increasing the span between the lateral ribs 3 and 3, the number of members can be reduced, and the possibility of occurrence of fatigue cracks can be reduced by reducing the number of welds.

In addition, the steel deck 1 in this embodiment is not limited to the above form, and various forms as shown in FIGS. 5 to 9 below can be applied.
5-9 is sectional drawing which shows the modification of the steel deck 1 in this embodiment, respectively.
In FIG. 5, the flanges 4B and 4B divided across the notch 4C of the vertical rib 4 are connected to each other by an attachment plate 6A. The attachment plate 6A is a plate material having substantially the same width as the flange 4B, and is inserted over the left and right sides of the web 3A of the horizontal rib 3 by being inserted into the scallop 3D of the horizontal rib 3. In this case, the scallop 3D of the lateral rib 3 is formed to be wide with a width dimension that allows insertion of the accessory plate 6A, that is, a width dimension larger than the flange 4B of the longitudinal rib 4. Then, both end portions of the attachment plate 6A and the flanges 4B and 4B are connected by welding.

  In FIG. 6, the flanges 4B and 4B divided across the notch 4C of the vertical rib 4 are connected to each other by a pair of accessory plates 6B and 6B, a bolt 7A, and a nut 7B. These attachment plates 6B and 6B are plate members arranged with the flange 4B sandwiched from above and below, and are inserted across the left and right sides of the web 3A of the horizontal rib 3 through the scallop 3D of the horizontal rib 3. Also in this case, the scallop 3D of the lateral rib 3 is formed wide with a width dimension capable of being inserted through the accessory plates 6B and 6B. Then, both end portions of the attachment plates 6B and 6B and the flanges 4B and 4B are connected by fastening bolts 7A and nuts 7B.

In FIG. 7, the flanges 4B and 4B divided across the notch 4C of the vertical rib 4 and the web 3A of the horizontal rib 3 are connected by a pair of auxiliary plates 6C. This splicing plate 6C is a steel material having a substantially the same width dimension as the flange 4B and formed in an L shape as a whole, and is disposed in contact with the lower surface of the flange 4B of the vertical rib 4 and the side surface of the web 3A of the horizontal rib 3. Has been. The flange 4B and the web 3A are connected to each other by welding the splicing plate 6C to each of the flange 4B and the web 3A. In this case, it is not necessary to form the scallop 3D of the lateral rib 3 wide as shown in FIGS.
Further, in FIG. 8, the flange 4B of the vertical rib 4 and the web 3A of the horizontal rib 3 are connected by the same attachment plate 6C, bolt 7A and nut 7B as in FIG.

In FIG. 9, the flanges 4B and 4B of the divided vertical ribs 4 are connected to each other by an attachment plate 6A similar to FIG. 5, and the flange 4B of the vertical ribs 4 and the web 3A of the horizontal ribs 3 are as shown in FIG. It is connected by the same attaching plate 6C. In this case, as in FIGS. 5 and 6, the scallop 3D of the lateral rib 3 is formed wide with a width dimension capable of inserting the accessory plate 6A.
As shown in FIGS. 5 to 9, the flanges 4B and 4B of the vertical rib 4 are connected to each other using the auxiliary plates 6A and 6B, or the flange 4B and the horizontal rib of the vertical rib 4 are connected to each other using the auxiliary plate 6C. By connecting the three webs 3A, the stress generated in the welds W1 between the webs 3A and 4A of the horizontal ribs 3 and the vertical ribs 4 can be dispersed, and the fatigue life of the welds W1 can be improved. it can.

In the steel slab 1 described above, it is desirable that the dimensions and design specifications are set as follows.
That is, the thickness T of the deck plate 5 is set in the range of 16 to 19 mm, the height H of the longitudinal rib 4 is set in the range of 350 to 700 mm, and the width of the flange 4B is 200 mm. It is preferable that the degree is set. Further, the interval dimension L1 between the vertical ribs 4 is set in a range of 400 to 500 mm, and the interval dimension (lateral rib span) L2 between the horizontal ribs 3 is set in a range of 3000 to 8000 mm (3 m or more and 8 m or less). It is preferable. Here, for example, the plate thickness dimension T of the deck plate 5, the horizontal rib 3 and the vertical rib 4 is set to 18 mm, the height dimension H of the vertical rib 4 is set to 500 mm, and the distance dimension L1 between the vertical ribs 4 is set. Even when the distance between the horizontal ribs 3 (horizontal rib span) L2 is set to 4000 mm when the distance is set to 450 mm, excessive stress is not generated at the intersection of the horizontal rib 3 and the vertical rib 4, that is, at the position of the welded portion W1. It has become. That is, it is preferable that the dimensions of the respective parts described above are set so that the generated stress at the position of the welded part W1 is about 4 kgf / mm ² (40 MPa) or less.

  Moreover, it is preferable that the height dimension H of the vertical ribs 4 and the distance dimension L1 between the vertical ribs 4 are set so that the torch of the multi-electrode welder enters the space between the vertical ribs 4. If the height dimension H of 4 is set to 580 mm or less and the distance dimension L1 is set to about 450 mm, no problem arises when the welding operation is automatically performed. Further, the distance L1 between the vertical ribs 4 is set so that the vehicle wheel does not enter above the distance between the vertical ribs 4, that is, the wheel is positioned on one of the vertical ribs 4. Preferably, when a W tire is used as a wheel, if the distance L1 between the vertical ribs 4 is set to 500 mm or less, generation of excessive stress in the deck plate 5 can be prevented. Moreover, it is preferable to set the distance dimension (lateral rib span) L2 between the lateral ribs 3 so that the front and rear wheels of the large vehicle do not enter the same span, and the distance between the front and rear wheels of a general large vehicle is targeted. In this case, if the distance L2 between the horizontal ribs 3 is set to 8000 mm or less, it is possible to prevent the generation of excessive stress at the deck plate 5, the vertical ribs 4, the horizontal ribs 3, and their joining positions.

As described above, in the present invention, the generated stress is reduced by devising the structure. However, there may be a case where fatigue is not completely prevented because the structure is not aimed, due to manufacturing or welding defects, design mistakes, and the like. In such a case, applying a grinder process or peening to the welded portion is extremely effective in preventing fatigue.
In particular, peening using ultrasound as a driving source, which has been used in recent years, is excellent in usability and has a much higher impact density than conventional peening, etc. Is extremely high, and is effective in reliably preventing the occurrence of fatigue cracks from the weld toe. Among them, the ultrasonic frequency band of 20 to 60 kHz, the amplitude at the tip of the wave guide of 20 μm or more, and the pin diameter of about 1 to 6 mm are preferable because both processing efficiency and effect are high.
In the conventional U-rib steel slab structure, since the U-rib has a closed cross section, the welded portion between the U-rib and the deck plate cannot be processed. On the other hand, the structure of the present invention uses open cross-section ribs, and the vertical rib interval and the horizontal rib interval are wider than the conventional U rib structure, which is advantageous in applying peening and grinder. There is basically no part that cannot be processed.

Below, the stress analysis by the design model (FEM) of the steel deck 1 demonstrated by the said embodiment was implemented, and the fatigue performance in the welding part W1 was examined (a 1st-5th Example, a 1st comparative example, and The first reference example will be described.
As shown in FIGS. 10 to 12, the design model of the steel deck 1 is a steel deck M1 that models the steel deck 1 of the embodiment, and a main girder M2 that models the main girder 2, It is configured to have a horizontal rib M3 that models the rib 3, M4 that models the vertical rib 4, and M5 that models the deck plate 5. 10 to 12, the interval dimension between the vertical ribs M4 is indicated by L1, the interval dimension between the horizontal ribs M3 (lateral rib span) is indicated by L2, and the height dimension of the vertical rib M4 is indicated by H.

[First embodiment]
The design model of the first embodiment is a steel deck M1 shown in FIG. 11, in which the plate thickness dimension T of the deck plate M5, the lateral rib M3 and the longitudinal rib M4 is set to 18 mm, and the height dimension of the longitudinal rib M4. H is set to 340 mm, the distance L1 between the vertical ribs M4 is set to 450 mm, and the distance L2 between the horizontal ribs M3 is set to 3000 mm. And in the design model of 1st Example, as shown in FIG. 4 of the said embodiment, the flanges 4B and 4B of the vertical rib 4 are not connected, and the flange 4B of the vertical rib 4 and the web 3A of the horizontal rib 3 are connected. Are not consolidated.

[Second Embodiment]
The design model of the second embodiment is a steel deck M1 shown in FIG. 10, in which the plate thickness dimension T of the deck plate M5, the lateral rib M3 and the longitudinal rib M4 is set to 18 mm, and the height dimension of the longitudinal rib M4. H is set to 500 mm, the distance L1 between the vertical ribs M4 is set to 450 mm, and the distance L2 between the horizontal ribs M3 is set to 4000 mm. And in the design model of 2nd Example, as shown in FIG. 4 of the said embodiment, the flanges 4B and 4B of the vertical rib 4 are not connected, and the flange 4B of the vertical rib 4 and the web 3A of the horizontal rib 3 are connected. Are not consolidated.

[Third embodiment]
The design model of the third embodiment is a steel deck M1 shown in FIG. 10, in which the plate thickness dimension T of the deck plate M5, the lateral rib M3 and the longitudinal rib M4 is set to 18 mm, and the height dimension of the longitudinal rib M4. H is set to 500 mm, the distance L1 between the vertical ribs M4 is set to 450 mm, and the distance L2 between the horizontal ribs M3 is set to 4000 mm. And in the design model of 3rd Example, as shown in FIG. 5 of the said embodiment, the flanges 4B and 4B of the vertical rib 4 are connected, while the flange 4B of the vertical rib 4 and the web 3A of the horizontal rib 3 are connected. And are not linked.

[Fourth embodiment]
The design model of the fourth embodiment is a steel deck M1 shown in FIG. 10, in which the plate thickness dimension T of the deck plate M5, the lateral rib M3 and the longitudinal rib M4 is set to 18 mm, and the height dimension of the longitudinal rib M4. H is set to 500 mm, the distance L1 between the vertical ribs M4 is set to 450 mm, and the distance L2 between the horizontal ribs M3 is set to 4000 mm. And in the design model of 4th Example, as shown in FIG. 7 of the said embodiment, the flanges 4B and 4B of the vertical rib 4 are not connected, On the other hand, the flange 4B of the vertical rib 4 and the web of the horizontal rib 3 3A is connected.

[Fifth embodiment]
The design model of the fifth embodiment is a steel deck M1 shown in FIG. 10, in which the plate thickness dimension T of the deck plate M5, the transverse rib M3 and the longitudinal rib M4 is set to 18 mm, and the height dimension of the longitudinal rib M4. H is set to 500 mm, the distance L1 between the vertical ribs M4 is set to 450 mm, and the distance L2 between the horizontal ribs M3 is set to 4000 mm. And in the design model of 5th Example, as shown in FIG. 9 of the said embodiment, the flanges 4B and 4B of the vertical rib 4 are connected, and the flange 4B of the vertical rib 4 and the web 3A of the horizontal rib 3 are also comprised. It is connected.

[First Comparative Example]
The design model of the first comparative example is a steel floor slab (not shown), the deck plate thickness is set to 12 mm, U ribs (U320) having a horizontal width of 320 mm are used as vertical ribs, and the spacing between the horizontal ribs The dimension L2 is set to 2000 mm.

[First Reference Example]
The design model of the first reference example is a steel deck M1 shown in FIG. 12, in which the plate thickness dimension T of the deck plate M5, the lateral rib M3 and the longitudinal rib M4 is set to 18 mm, and the height dimension of the longitudinal rib M4. H is set to 190 mm, the distance L1 between the vertical ribs M4 is set to 450 mm, and the distance L2 between the horizontal ribs M3 is set to 2000 mm. In the design model of the first reference example, as shown in FIG. 4 of the above embodiment, the flanges 4B and 4B of the vertical rib 4 are not connected to each other, and the flange 4B of the vertical rib 4 and the web 3A of the horizontal rib 3 are used. Are not consolidated. The design model of the first reference example is a form included in the technical scope of the present invention, although it deviates from the range of the desired dimensions and design specifications as described above.

FIG. 13 shows the stress generated in the welded portion W1 (see FIG. 3) between the vertical rib M4 and the horizontal rib M3 as a result of the stress analysis of the first and second examples and the first reference example. . In FIG. 13, the vertical axis represents the height position from the deck plate M5, and the horizontal axis represents the generated stress of the welded portion W1. Further, in FIG. 13, the result of the first reference example (horizontal rib interval 2000 mm) is indicated by a black triangle (▲), and the result of the first example (lateral rib interval 3000 mm) is indicated by a black square mark (■). The results of the second embodiment (lateral rib interval 4000 mm) are indicated by black diamonds (♦).
From FIG. 13, it can be seen that in the first reference example, the generated stress in the welded portion W1 exceeds 3 kgf / mm ² in the entire height section and exceeds 4 kgf / mm ² in the section approximately 100 mm from the deck plate M5. . Further, in the first embodiment, the generated stress in the welded portion W1 is smaller than that in the first reference example in the entire height section and exceeds 4 kgf / mm ² in the section about 50 mm from the deck plate M5, but the other sections So it can be seen that remains below 4 kgf / mm ^2. Furthermore, in the second embodiment, it can be seen that the generated stress in the welded portion W1 is smaller than that of the first reference example in the entire height section and is 4 kgf / mm ² or less in the entire section. Although illustration is omitted, if the flanges 4B and 4B of the vertical rib 4 or the flange 4B of the vertical rib 4 and the web 3A of the horizontal rib 3 are connected as in the third to fifth embodiments, welding is performed. It is obvious that the generated stress in the portion W1 is further reduced as compared with the first and second embodiments. From the above, in the embodiment of the present invention, the generated stress of the welded portion W1 is approximately 4 kgf / mm ² or less, and the design specifications can be satisfied.

Moreover, about the 1st-5th Example, a 1st comparative example, and a 1st reference example, when the number of welding locations per 1 m < ² > of floor areas of the steel deck M1 and the welding amount were compared, design of 1st Example In the model (lateral rib interval 3000 mm), the number of welds is reduced to about 56% compared to the first comparative example, the welding amount is almost the same, and the number of welds is about 35% compared to the first reference example. It was found that the welding amount was reduced to about 58%. Further, in the design models of the second to fifth examples (lateral rib interval 4000 mm), the number of welding points is reduced to about 44% and the welding amount is reduced to about 96% compared to the first comparative example. It was found that the number of welded parts was reduced to about 27% and the welding amount was reduced to about 56% compared to 1 reference example. In addition, regarding the amount of steel material per 1 m ^{2 of} floor area obtained by integrating the weight of each member, the difference is that the design models of the first to fifth examples slightly increase more than the first comparative example and the first reference example. It was found that the effect of reducing the number of processing steps by reducing the number of welds and the amount of welding is large.

  Next, FIG. 14 shows the result of verifying the correlation between the height dimension H of the longitudinal rib M4 and the interval dimension L2 of the lateral rib M3 based on the design models of the first and second embodiments. In FIG. 14, the vertical axis represents the height dimension H of the vertical rib M4, and the horizontal axis represents the interval dimension L2 of the horizontal rib M3. In this verification, the height dimension H of the vertical ribs M4 and the distance dimension L2 of the horizontal ribs M3 that generate the same level of stress as in the first and second examples were calculated. Further, for comparison with the vertical rib M4 having the flange 4B (indicated by a black rhombus mark (♦) in FIG. 14), a plate rib having no flange (in FIG. 14, a black square mark (■) The model using the vertical rib M4 was also verified.

  From FIG. 14, in order to set the distance L2 between the horizontal ribs M3 to, for example, 3000 mm, when the plate rib is used, the height dimension H is required to be 500 mm or more. In the vertical rib M4 of this embodiment, It can be seen that the height dimension H is within 340 mm. Further, when a plate rib is used as the vertical rib M4, the height dimension H cannot be increased to 600 mm or more due to the restriction of the protruding length of the free end. Become. On the other hand, in the vertical rib M4 of the present embodiment, by increasing the height dimension H to about 680 mm, the interval dimension L2 of the horizontal rib M3 can be expanded to 5000 mm. And as demonstrated also in the said embodiment, in this invention, since the freedom degree of the height dimension H of a vertical rib is high and the height dimension H can be enlarged easily without inhibiting assembly property, fatigue performance is improved. It has been found that an increase in the distance L2 between the lateral ribs M3 can be realized while ensuring and suppressing the manufacturing cost.

Next, FIG. 15 shows the result of examining the relationship between the dimension of the lateral rib and the generated stress based on the design model of the present embodiment.
Here, in the design, the height dimension H of the vertical ribs is determined from the horizontal rib interval L2. On the other hand, if the height dimension of the horizontal ribs is constant, the height dimension of the vertical ribs. When H is large, the notch provided in the lateral rib is increased, so that the effective cross-sectional area of the lateral rib is reduced, and the generated stress tends to increase at the welded portion between the lateral rib and the deck plate.
Therefore, in this study, for the model with the horizontal rib interval L2 of 4 m (the height dimension of the vertical rib is H = 500 mm), the height of the horizontal rib and the thickness of the web are changed to adjust the stress to the generated stress. The effects were compared. In FIG. 15, the vertical axis represents local stress obtained from FEM, which is different from the conventional average stress expression. From FIG. 15, the stress generated at the evaluation site (the end of the welded portion between the lateral rib and the deck plate) decreases as the web thickness of the lateral rib increases and the height of the lateral rib increases. I understand. And since the vertical axis in FIG. 15 is local stress, it is not possible to determine whether the fatigue strength is sufficient only by this numerical value. However, for example, if it is similar to the valve plate of the conventional structure, there is almost no problem in fatigue performance. It is not considered. Therefore, the height dimension and the plate thickness of the lateral rib may be set so as to generate the same level of stress as that of the valve plate rib.

The best configuration, method, and the like for carrying out the present invention have been disclosed above, but the present invention is not limited to this. That is, the invention has been illustrated and described with particular reference to certain specific embodiments, but without departing from the spirit and scope of the invention, Various modifications can be made by those skilled in the art in terms of material, quantity, and other detailed configurations.
Therefore, the description limiting the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

It is a perspective view showing a road bridge using a steel deck according to an embodiment of the present invention. It is a perspective view which shows the state before the assembly of the horizontal rib and vertical rib of the said steel deck. It is a perspective view which shows the state which integrated the said horizontal rib and the vertical rib. It is sectional drawing which looked at the said steel deck from the side of the vertical rib. It is sectional drawing which shows the modification of the steel deck in the said embodiment. It is sectional drawing which shows the modification of the steel deck in the said embodiment. It is sectional drawing which shows the modification of the steel deck in the said embodiment. It is sectional drawing which shows the modification of the steel deck in the said embodiment. It is sectional drawing which shows the modification of the steel deck in the said embodiment. It is a perspective view which shows the design model of the steel deck according to the Example of this invention. It is a perspective view which shows the design model of the steel deck according to the Example of this invention. It is a perspective view which shows the design model of the steel deck according to the Example of this invention. It is a graph which shows the generated stress in the Example of this invention. It is a graph which shows the correlation with the height dimension of a vertical rib and the horizontal rib space | interval dimension in the Example of this invention. It is a graph which shows the relationship between the dimension of a horizontal rib and the generated stress in the Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steel deck, 2 ... Main girder, 3 ... Horizontal rib, 3A ... Web, 3B ... Flange, 3C ... Notch, 3D ... Scallop, 4 ... Vertical rib, 4A ... Web, 4B ... Flange, 4C ... Notch 5 ... Deck plate, 6A-6C ... Saddle plate, 7A ... Bolt, 7B ... Nut, H ... Vertical rib height dimension, L1 ... Vertical rib spacing dimension, L2 ... Horizontal rib spacing dimension, T ... Thickness Dimensions, W1, W2, W3 ... welds.

Claims (8)

A steel floor comprising a plurality of horizontal ribs supported by the main girder, a plurality of vertical ribs supported crossing the horizontal ribs, and a deck plate welded and fixed to the upper side of the horizontal ribs and the vertical ribs Version,
The lateral rib has at least a web extending vertically, and the web is formed with a plurality of notches that open upward and extend downward.
The vertical rib has a substantially inverted T-shaped or L-shaped cross section from a vertically extending web and a flange continuous to a lower end portion of the web, and the flange at a position corresponding to the notch of the lateral rib is Notched and formed,
A steel slab, wherein the web of the vertical rib is welded along the notch in a state where the web of the vertical rib is inserted into the cut of the horizontal rib. In the steel deck according to claim 1,
The steel floor slab characterized in that the interval between the lateral ribs is set in a range of 3 m or more and 8 m or less. In the steel deck according to claim 1 or 2,
A steel floor slab characterized in that the width dimension of the notch of the horizontal rib is set smaller than the width dimension of the flange of the vertical rib. In the steel deck according to any one of claims 1 to 3,
A wide scallop having a larger width dimension than the flange of the vertical rib is formed at the lower end of the notch of the horizontal rib,
The steel floor slab characterized in that the flanges of the cut-out vertical ribs are connected to each other through an attachment plate inserted into the scallop. In the steel deck according to any one of claims 1 to 4,
A steel floor slab, characterized in that the web of the horizontal rib and the flange of the vertical rib are joined together via an attachment plate. A steel floor comprising a plurality of horizontal ribs supported by the main girder, a plurality of vertical ribs supported crossing the horizontal ribs, and a deck plate welded and fixed to the upper side of the horizontal ribs and the vertical ribs A method of manufacturing a plate,
The transverse rib has at least a web extending vertically, and the longitudinal rib has a substantially inverted T-shaped or L-shaped cross section from a vertically extending web and a flange continuous with a lower end portion of the web. Each formed,
A plurality of notches are formed in the web of the horizontal ribs so as to open upward and extend downward, and the flanges of the vertical ribs at positions corresponding to the notches of the horizontal ribs are cut out. A method for producing a steel slab, wherein the web of the longitudinal rib is inserted through the web and the web of the transverse rib and the longitudinal rib are welded together along the notch. In the manufacturing method of the steel deck according to claim 6,
When forming the notch of the lateral rib, a wide scallop having a width dimension larger than the flange of the vertical rib is formed at the lower end of the notch,
A steel floor slab, wherein the web of the vertical rib is inserted into the notch of the horizontal rib, and then the flanges of the notched vertical rib are connected to each other via an attachment plate inserted into the scallop. Production method. In the manufacturing method of the steel deck according to claim 6 or 7,
A method for producing a steel slab, comprising inserting the web of the vertical rib into the notch of the horizontal rib, and then joining the web of the horizontal rib and the flange of the vertical rib through an attachment plate.

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