Method for joining composite floor slabs

Abstract

To provide a joining method of a composite floor slab capable of performing work for connecting bottom plates of the composite floor slab to each other by bolts without installing a scaffold.SOLUTION: The end sides of first reinforcing bars 12 of a composite floor slab 10 adjacent to each other are arranged so that bolts 16 are positioned below parts between the first reinforcing bars 12, and since bottom plates 11 are connected to each other by fastening nuts 16b to the bolts 16 temporarily fixed to the bottom plate 11 in advance from above through between the first reinforcing bars 12, the fastening work of the nuts 16b can be performed from above the bottom plates 11. In this case, the first reinforcing bars 12 of one composite floor slab 10 and the first reinforcing bars 12 of the other composite floor slab 10 are arranged so that a wide interval A1 and a narrow interval A2 are alternately formed, and the bolts 16 are positioned below the wide interval A1, so that a space for fastening work of nuts from between the reinforcing bars can be sufficiently secured.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for joining composite deck plates used in bridges such as general roads and highways, for example.

Background Art

[0002] Conventionally, as a composite deck plate used for bridge construction, for example, a steel bottom plate manufactured in a factory is fixed onto a main girder on site, and reinforcement bars are arranged on the bottom plate and concrete is placed to construct the deck plate (see, for example, Patent Document 1). In construction using such a composite deck plate, since concrete can be placed directly on the bottom plate, there is no need to use a formwork, and the efficiency of on-site work can be improved. However, in the construction method of placing concrete for the entire deck plate on site, since the placement of concrete on site and a long curing period are required, the shortening of the construction period could not be sufficiently achieved.

[0003] Also, there is known a method of improving the efficiency of on-site construction and shortening the construction period by using a precast composite deck plate manufactured integrally with concrete in a factory in advance (see, for example, Patent Document 2). In this construction method, the composite deck plate is installed on the main girder, and packing concrete is placed between the end faces of adjacent composite deck plates. However, in order to ensure the load transfer force between the composite deck plates, a plurality of reinforcement bars are extended from the end face of the composite deck plate into the packing portion, and the bonding strength between the composite deck plate and the packing concrete is increased by each reinforcement bar.

Prior Art Documents

Patent Documents

[0004] ?

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in on-site construction using the aforementioned composite floor slab, the ends of the bottom plates of the composite floor slab, which are installed on the main girders, are connected with splice plates and high-strength bolts, and then infill concrete is poured onto the bottom plates. However, the fastening of the high-strength bolts is carried out by setting up scaffolding below the floor slab, which requires a great deal of time and effort to set up and remove the scaffolding. For this reason, even when using precast composite floor slabs, which require less on-site work, the amount of work and cost increases due to the installation of scaffolding, so the overall efficiency of on-site construction cannot be fully achieved.

[0006] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a method for joining composite floor slabs that allows the bottom plates of composite floor slabs to be connected with bolts without the need to install scaffolding. [Means for solving the problem]

[0007] To achieve the above objective, the present invention uses bolts to connect the ends of the bottom plates of a composite floor slab, which is formed by placing reinforcing bars on a steel bottom plate and pouring concrete. and nuts In a method for joining multiple composite floor slabs in a predetermined direction, which involves connecting them and filling the gaps between the concrete end faces of adjacent composite floor slabs with a filler material, the end faces of the reinforcing bars extending in the predetermined direction are alternately arranged in a direction perpendicular to the predetermined direction so that they are positioned above the connecting portion between the bottom plates of adjacent composite floor slabs, and the reinforcing bars of one composite floor slab and the reinforcing bars of the other composite floor slab are connected. A tightening tool for fastening the nut can be inserted through Wide spacing and Rather than that wide gap They are arranged so that narrow gaps are formed alternately, The aforementioned The bolts are positioned at a wide gap below, and they are attached to the bolts that have been temporarily fixed to the bottom plate beforehand. The aforementioned From between the widely spaced reinforcing bars By tightening tools The bottom plates are connected to each other by fastening nuts.

[0008] As a result, the bottom plates are connected by fastening nuts to bolts that have been temporarily fixed to the bottom plates beforehand, making it possible to fasten the nuts to the bolts from above the bottom plates, through the gaps between the reinforcing bars. In this case, since the bolts are located below the wide gaps between the reinforcing bars, there is ample space to fasten the nuts from between the bars. [Effects of the Invention]

[0009] According to the present invention, the bolting of the bottom plates of the composite floor slab can be performed from above the bottom plate, passing through the reinforcing bars. Therefore, there is no need to set up scaffolding below the composite floor slab to perform the bottom plate connection work, and the overall efficiency of on-site construction can be improved without increasing the man-hours and costs associated with scaffolding. In this case, sufficient space can be secured to fasten the nuts through the reinforcing bars, so even when the reinforcing bars are arranged at high density, the bolting of nuts can be easily performed by passing them through the reinforcing bars. [Brief explanation of the drawing]

[0010] [Figure 1] Plan view of a composite floor slab showing one embodiment of the present invention. [Figure 2] Plan view of the main parts of the composite floor slab [Figure 3] Side cross-sectional view of the main part of the composite floor slab [Figure 4] Side cross-sectional view showing the joining process of composite floor slabs. [Figure 5] Side cross-sectional view showing the joining process of composite floor slabs. [Figure 6] Side cross-sectional view showing the joining process of composite floor slabs. [Figure 7] Side cross-sectional view showing the joining process of composite floor slabs. [Figure 8] Side cross-sectional view showing the joint state of the composite floor slab. [Figure 9] Side cross-sectional view showing the joining process of a composite floor slab in another embodiment of the present invention. [Figure 10] Side cross-sectional view showing the joining process of composite floor slabs. [Figure 11] Side cross-sectional view showing the joining process of composite floor slabs. [Figure 12] Side cross-sectional view showing the joining process of the composite deck

Embodiments for Carrying out the Invention

[0011] Figs. 1 to 8 show an embodiment of the present invention, and show a composite deck used for bridges such as general roads and highways, for example.

[0012] The composite deck 10 shown in the figure is installed on the main girder 20 and is erected by being joined in the bridge axis direction with other composite decks 10.

[0013] The composite deck 10 is composed of a steel bottom plate 11 forming the bottom surface of the deck body, a plurality of first reinforcing bars 12 as force - transmitting bars extending in the bridge axis direction, a plurality of second reinforcing bars 13 as main reinforcing bars extending in a direction perpendicular to the bridge axis, a plurality of supplementary stiffening members 14 fixed on the bottom plate 11, and a concrete part 15 placed on the bottom plate 11. The bottom plate 11 is connected to the bottom plate 11 of other composite decks 10 by bolts 16 and attachment plates 17.

[0014] The bottom plate 11 is made of a flat steel plate, and a plurality of bolt insertion holes 11a through which bolts 16 are inserted are provided on both ends in the bridge axis direction. Each bolt insertion hole 11a is arranged at an interval in a direction perpendicular to the bridge axis and is provided so as to penetrate the bottom plate 11 in the thickness direction. Further, a plurality of studs 11b embedded in the concrete part 15 or in the filling concrete 19 described later are provided on the bottom plate 11.

[0015] Each first reinforcing bar 12 is arranged perpendicular to the bridge axis so as to be located above the base plate 11, with both ends extending outside the concrete section 15. Each end of the first reinforcing bar 12 is provided with an anchoring portion 12a for anchoring to the infill concrete described later, and the anchoring portion 12a is formed to expand radially to the first reinforcing bar 12. As shown in Figure 2, each first reinforcing bar 12 is arranged alternately with each other's first reinforcing bar 12 in a direction perpendicular to the bridge axis. In this case, each first reinforcing bar 12 is arranged such that the first reinforcing bar 12 of one composite deck slab 10 and the first reinforcing bar 12 of the other composite deck slab 10 are spaced one apart at a wide interval A1 and a narrow interval A2, and the bolts 16 are positioned below the wide interval A1.

[0016] Each second reinforcing bar 13 is arranged in the direction of the bridge axis so as to be located above the base plate 11 and positioned above each first reinforcing bar 12.

[0017] Each stiffening member 14 is made of steel (for example, channel steel) extending in a direction perpendicular to the bridge axis and is arranged at intervals from one another in the direction of the bridge axis.

[0018] The concrete section 15 is cast onto the base plate 11 using formwork in a factory or the like, forming a floor slab that spans the entire width of the base plate 11. The concrete section 15 contains embedded first reinforcing bars 12, second reinforcing bars 13, stiffeners 14, and studs 11b, with the ends of the base plate 11 and the ends of the first reinforcing bars 12 extending horizontally outward from the end face 15a of the concrete section 15. In this case, each first reinforcing bar 12 is positioned above the vertical center of the concrete section 15. The concrete section 15 is also provided with multiple holes 15b through which shear prevention members of the main girder 20 are inserted.

[0019] The bolts 16 are high-strength bolts and are temporarily fixed to the base plate 11 before the composite floor slab 10 is brought to the construction site. At that time, as shown in Figure 3, the bolts 16 are inserted from below into the bolt insertion holes 11a of the base plate 11 and temporarily fixed to the base plate 11 by screwing in temporary fixing nuts 16a from above the base plate 11. For the temporary fixing nuts 16a, for example, a ring-shaped member made of synthetic resin with a thickness smaller than that of the splice plate 17 is used.

[0020] The splice plate 17 is made of a steel plate extending perpendicular to the bridge axis and is formed to rest on the upper surface of the end side of each bottom plate 11 across adjacent composite deck plates 10. The splice plate 17 is provided with a plurality of bolt insertion holes 17a through which bolts 16 are inserted, and the bolt insertion holes 17a are formed with an inner diameter larger than the outer diameter of the temporary fixing nuts 16a.

[0021] The composite floor slab 10, constructed as described above, is manufactured in a factory or similar facility and then transported to the construction site. At that time, high-strength bolts 16 are temporarily fixed to the bottom plate 11 of the composite floor slab 10.

[0022] The joining process of the composite floor slab 10 will be explained below with reference to Figures 4 to 8.

[0023] First, the composite deck slabs 10 that have been delivered to the site are installed on the main girders 20 so as shown in Figure 5, positioned in one direction along the bridge axis, relative to the composite deck slabs 10 that have been previously installed on the main girders 20 as shown in Figure 4. At this time, the bottom plates 11 of the composite deck slabs 10 are butted together in the direction along the bridge axis with a small gap between them, and a gap-filling area is formed between the concrete sections 15 of each composite deck slab 10. In addition, anti-slip members (not shown) for the main girders 20 are placed in the holes 15b of the concrete section 15.

[0024] Next, as shown in Figure 6, a splice plate 17 is placed on the upper end surface of the bottom plate 11 of each composite floor slab 10, and a nut 16b is screwed onto the bolt 16 that is temporarily fixed to the bottom plate 11 and temporarily tightened. At this time, since the temporary fixing nut 16a is placed inside the bolt insertion hole 17a of the splice plate 17, the temporary fixing nut 16a does not interfere with the nut 16b.

[0025] In this case, in adjacent composite floor slabs 10, as shown in Figure 2, the bolts 16 are located below the wide spacing A1 between each first reinforcing bar 12. Therefore, as shown in Figure 7, the nuts 16b are tightened onto the bolts 16 using a tightening tool 30 (for example, a shear wrench with a long socket) that can be inserted through the wide spacing A1 from above each first reinforcing bar 12.

[0026] Subsequently, as shown in Figure 8, multiple reinforcing bars 18 extending perpendicular to the bridge axis are placed on the first reinforcing bars 12 located in the infill areas between each concrete section 15, spaced apart in the bridge axis direction, and infill concrete 19 is poured into the infill areas between each concrete section 15 as infill material. For example, fast-setting concrete is used for the infill concrete 19. As a result, each first reinforcing bar 12 in the infill area becomes integrated with the infill concrete 19, and the bonding strength between each composite deck slab 10 is increased by the adhesion force and bearing pressure (force resisting horizontal shear force) generated between each first reinforcing bar 12 and the infill concrete 19. At that time, the adhesion force and bearing pressure are further increased by the anchoring portion 12a provided at the end of each first reinforcing bar 12, so as shown in Figure 3, the length L of the overlapping portion in the bridge axis direction between the first reinforcing bars 12 of each composite deck slab 10 can be made shorter than when reinforcing bars without anchoring portions 12a are used.

[0027] Furthermore, by filling the holes 15b in the concrete section 15 with non-shrink mortar, the shear-preventing member (not shown) of the main girder 20 and the concrete section 15 are integrated.

[0028] As described above, according to this embodiment, the ends of the first reinforcing bars 12 of adjacent composite floor slabs 10 are arranged alternately in a direction perpendicular to the bridge axis so that they are positioned above the connecting portion between the bottom plates 11, and bolts 16 are positioned below the space between each first reinforcing bar 12. The bottom plates 11 are connected by fastening nuts 16b from above through the space between the first reinforcing bars 12 onto the bolts 16 that have been temporarily fixed to the bottom plates 11 in advance. This allows the work of connecting the bottom plates 11 with bolts 16 to be done from above the bottom plates 11. As a result, there is no need to set up scaffolding below the composite floor slabs 10 to perform the work of connecting the bottom plates 11, thus avoiding the increase in man-hours and costs associated with setting up scaffolding and improving the overall efficiency of on-site construction.

[0029] Furthermore, the first reinforcing bars 12 of one composite floor slab 10 and the first reinforcing bars 12 of the other composite floor slab 10 are arranged so that wide spacing A1 and narrow spacing A2 are alternately formed, and the bolts 16 are positioned below the wide spacing A1. This ensures that there is sufficient space to fasten the nuts from between the reinforcing bars, so that even when the first reinforcing bars 12 are arranged at high density, the nuts 16b can be easily fastened to the bolts 16 through the gaps between the first reinforcing bars 12.

[0030] Figures 9 to 12 show another embodiment of the present invention, in which a shear prevention member 22, which can be separated into upper and lower members, is provided on the upper surface of the main girder 20. Components equivalent to those in the above embodiment are denoted by the same reference numerals.

[0031] The anti-slip member 22 of this embodiment consists of a lower member 22a positioned on the main girder 20, an upper member 22b positioned above the lower member 22a, and a connecting member 22c that connects the lower member 22a and the upper member 22b. The lower member 22a is a shaft-shaped member with a male thread formed on it, and its lower end is fixed to the upper surface of the main girder 20 by welding. The upper member 22b is a shaft-shaped member with a male thread formed on it, and a head similar to that of a bolt is formed at its upper end. The connecting member 22c is a tall nut, and the lower end is screwed into the lower member 22b, and the other end is screwed into the upper member 22b, thereby connecting the lower member 22a and the upper member 22b.

[0032] The joining process of the composite floor slab 10 will be explained below with reference to Figures 9 to 12. The bottom plate 11 is positioned slightly higher than the upper surface of the main girder 20 by the haunch portion 11c.

[0033] In this embodiment, as shown in Figure 9, the splice plate 17 is temporarily held below the end of the first reinforcing bar 12 of one of the composite floor slabs 10 that has been installed in advance on the main girder 20. In this case, for example, the splice plate 17 is temporarily held in place by hooking a wire 17b passed through the bolt insertion hole 17a of the splice plate 17 onto the first reinforcing bar 12, thereby suspending the splice plate 17 from the first reinforcing bar 12.

[0034] Next, as shown in Figure 10, the other composite deck slab 10, which is suspended by a crane (not shown), is moved in the bridge axis direction toward the other composite deck slab 10 from a height position where the bottom plate 11 of the other composite deck slab 10 is located between the bottom plate 11 of the first composite deck slab 10 and the first reinforcing bar 12.

[0035] In this case, if the other composite floor slab 10 is to be lowered from directly above its installation position, the extension length of the first reinforcing bar 12 of one composite floor slab 10 must be shorter than the tip of

[0036] In this case, by leaving the shear prevention member 22 on the main girder 20 on which the other composite floor slab 10 is installed in a state where only the lower member 22a is attached and the upper member 22b is not attached, sufficient vertical space S is secured between the first reinforcing bar 12 of the one composite floor slab 10 and the lower member 22a of the shear prevention member 22, allowing the end side of the bottom plate 11 of the other composite floor slab 10 to be inserted.

[0037] Next, as shown in Figure 11, the other composite floor slab 10 is lowered onto the main girder 20, and the upper member 22b of the shear prevention member 22, which is placed in the hole 15b of the other composite floor slab 10, is attached to the lower member 22a by the connecting member 22c. Note that the work of attaching the upper member 22b to the lower member 22a may be performed after the fastening process of the splice plate 17, which will be described later.

[0038] Next, as shown in Figure 12, the temporary holding of the splice plate 17 is released, and the splice plate 17 is placed on the base plate 11. The bolts 16 that are temporarily fixed to the base plate 11 of each composite floor slab 10 are then inserted into the bolt insertion holes 17a of the splice plate 17. Note that the process of fastening nuts 16b to the bolts 16 and the subsequent processes are the same as in the above embodiment, so their explanation is omitted.

[0039] Thus, according to this embodiment, with respect to one composite deck slab 10 installed on the main girder 20, the other composite deck slab 10 is moved toward the one composite deck slab 10 in the bridge axis direction from a height position where the bottom plate 11 of the one composite deck slab 10 is located between the bottom plate 11 of the one composite deck slab 10 and the first reinforcing bar 12, and then the other composite deck slab 10 is lowered onto the main girder 20. As a result, the first reinforcing bar 12 of the one composite deck slab 10 and the bottom plate 11 of the other composite deck slab 10 do not interfere with each other in the vertical direction, and the joint strength between the first reinforcing bar 12 and the infill concrete 19 can be increased by extending the first reinforcing bar 12 longer than the end of the bottom plate 11.

[0040] Furthermore, the shear prevention member 22 that protrudes upward from the upper surface of the main girder 20 is formed to be separable into two parts, an upper and an lower member 22a and an upper member 22b. When installing the other composite deck slab 10, the shear prevention member 22 of the main girder 20 is positioned with only the lower member 22a attached. The other composite deck slab 10 is then moved toward the first composite deck slab 10 in the bridge axis direction, and after lowering the other composite deck slab 10 onto the main girder 20, the upper member 22b is attached to the shear prevention member 22. This ensures that there is sufficient vertical space S between the first reinforcing bar 12 of the first composite deck slab 10 and the lower member 22a of the shear prevention member 22 to insert the end of the bottom plate 11 of the other composite deck slab 10, making it easy to move the other composite deck slab 10 in the bridge axis direction.

[0041] Furthermore, by temporarily holding the splice plate 17 below the first reinforcing bar 12 of one composite floor slab 10, and then lowering the other composite floor slab 10 onto the main girder 20, the temporary holding of the splice plate 17 is released and the splice plate 17 is fastened to the base plate 11 with bolts 16 and nuts 16b, there is no need to position the splice plate 17 after installing the other composite floor slab 10 onto the main girder 20, and the connection work of the base plate 11 can be performed efficiently.

[0042] In the embodiments described above, the splice plates 17 are shown to be temporarily held below the first reinforcing bars 12. However, multiple splice plates, each with a short length in the direction perpendicular to the bridge axis, may be used, and each splice plate may be placed on the bottom plate 11 from above the first reinforcing bars 12, through the gaps between the first reinforcing bars 12.

[0043] Furthermore, although the above embodiments show the composite deck slabs 10 being joined together in the direction of the bridge axis, the method can also be applied when joining them in a direction perpendicular to the bridge axis.

[0044] Furthermore, the above embodiments are merely examples of the present invention, and the present invention is not limited to those described above. [Explanation of Symbols]

[0045] 10... Composite floor slab, 11... Base plate, 12... First reinforcing bar, 15... Concrete section, 16... Bolt, 16a... Temporary fixing nut, 16b... Nut, 17... Splice plate, 19... Infill concrete, 20... Main girder, 22... Shear prevention member, 22a... Lower member, 22b... Upper member, 22c... Connecting member.

Claims

1. In a method for joining composite floor slabs, in which the ends of the bottom plates of a composite floor slab, formed by placing reinforcing bars on a steel bottom plate and pouring concrete, are connected with bolts and nuts, and a gap-filling material is filled between the concrete end faces of adjacent composite floor slabs, the following is described: The ends of the reinforcing bars extending in the predetermined direction are arranged alternately in a direction perpendicular to the predetermined direction so that they are positioned above the connecting portions of the bottom plates of adjacent composite floor slabs. The reinforcing bars of one composite floor slab and the reinforcing bars of the other composite floor slab are arranged such that wide gaps, through which a tightening tool for fastening the nuts can be inserted, and narrower gaps are alternately formed, and the bolts are positioned below the wide gaps. The bottom plates are connected by fastening nuts to bolts that have been temporarily fixed to the bottom plates beforehand, using the aforementioned tightening tool, through the wide-spaced reinforcing bars. A method for joining composite floor slabs, characterized by the features described above.

2. After moving one composite floor slab toward the other composite floor slab in the predetermined direction relative to one composite floor slab installed on the main girder, from a height position where the bottom plate of the other composite floor slab is located between the bottom plate and the reinforcing bars of the first composite floor slab, The other composite deck is lowered onto the main girder. The method for joining composite floor slabs according to feature 1.

3. The anti-slip member that protrudes upward from the upper surface of the main girder is formed to be separable into two upper and lower members. With the shear prevention member of the main girder where the other composite floor slab is to be installed only the lower member, the other composite floor slab is moved toward the one composite floor slab in the predetermined direction, After lowering the other composite deck onto the main girder, Attach the upper member to the anti-slip member. The method for joining composite floor slabs according to feature 2.

4. A splice plate for connecting the bottom plate is temporarily held in place below the reinforcing bars of one of the composite floor slabs. After lowering the other composite deck onto the main girder, Release the temporary hold on the splice plate and place the splice plate on the base plate. A method for joining composite floor slabs according to claim 2 or 3, characterized by the features described above.

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