JP6713419B2 - Suspension method and suspension structure - Google Patents

Description

The present invention relates to a method for suspending a reinforcing bar cage and a suspending structure.

Conventionally, as a technique in such a field, an overhanging construction method described in Patent Document 1 below is known. In this method, the mobile work vehicle is extended from the tip of the existing bridge girder, and the reinforced concrete bridge girder block is formed to extend from the tip of the existing bridge girder. By repeating such overhanging construction, the bridge girder will be gradually expanded. The reinforcing bars embedded in the bridge girder block are assembled in advance as a reinforcing bar cage, the reinforcing bar cage is hung and moved using a hoist or the like, and installed at the concrete pouring position of the bridge girder block.

Japanese Patent Laid-Open No. 11-021820

In the case of suspending a pre-assembled rebar cage as in the example of Patent Document 1 described above, the rebar cage is generally bent due to its own weight. In this type of reinforcing bar basket, the intersecting portions of the reinforcing bars extending vertically and horizontally are bound by binding wires. If the bending of the reinforcing bar cage is large, irreversible deformation is likely to occur particularly in the above-mentioned binding portion and the like, and as a result, the deformation of the entire reinforcing bar cage may remain. Further, the above-mentioned binding portion may be damaged and the binding work may have to be redone.

In view of such a problem, an object of the present invention is to provide a suspending method and a suspending structure that suppress the bending of the reinforcing bar cage.

The hanging method of the present invention is a bottom slab rebar portion embedded in a bottom slab of a reinforced concrete structure, and a pair of opposing side walls that are provided so as to stand up from both end edges of the bottom slab rebar portion and are embedded in side walls of the reinforced concrete structure. A method of suspending a reinforcing bar basket having a reinforcing bar portion, which is installed below a bottom plate reinforcing bar extending in a direction opposite to a side wall reinforcing bar portion along a lower surface of the bottom plate reinforcing bar direction and is substantially orthogonal to the bottom plate reinforcing bar. And a first suspension beam having a flexural rigidity higher than that of the bottom slab, and extending substantially parallel to the direction of extension of the bottom slab above the bottom slab, and Also has a high bending rigidity, and the second suspension beam member connected to the first suspension beam member with the bottom plate underneath is sandwiched, and in each of the side wall reinforcements, the center of the side wall reinforcements in the thickness direction of the side wall. And a pair of suspension tension members that extend through the upper portion to the upper end of the side wall reinforcing bars and that suspend and support the second suspension supporting beam members with both ends, and are arranged above each of the side wall reinforcing bars and are suspended. A pair of suspending devices to which the upper ends of the tension receiving members are connected are installed, and the pair of suspending devices are suspended by a predetermined suspending means.

Further, the suspension structure of the present invention, a bottom slab rebar portion to be embedded in the bottom slab of the reinforced concrete structure, a pair of opposed to be provided so as to stand up from both end edges of the bottom slab rebar portion, each being embedded in the side wall of the reinforced concrete structure A structure for suspending a reinforcing bar basket having a side wall reinforcing bar portion, which is installed below a bottom plate reinforcing bar extending in a direction opposite to the side wall reinforcing bar portion along a lower surface of the bottom plate reinforcing bar portion, and is substantially orthogonal to the bottom plate reinforcing bar. And a first hanging beam having a bending rigidity higher than that of the bottom slab, and extending substantially parallel to the direction of extension of the bottom slab above the bottom slab, and A second suspension beam member having a bending rigidity higher than that of the reinforcement and being connected to the first suspension beam member with the bottom slab being sandwiched, and the sidewall reinforcing bar portion, in each of the sidewall reinforcing bar portions, the thickness direction of the sidewall of the sidewall reinforcing bar portion. And a pair of suspension tension members that extend through the central portion of the side wall to the upper end of the side wall reinforcing bars and that suspend and support the second suspension beam members with both ends, and are arranged above each of the side wall reinforcing bars. And a pair of suspending devices to which the upper ends of the suspension tension members are connected and which are suspended by a predetermined suspending means.

According to the above-described suspension method and suspension structure, the first suspension beam member and the second suspension beam member having bending rigidity higher than that of the bottom slab are installed vertically and horizontally along the lower surface of the bottom slab rebar portion. The bottom slab is vertically sandwiched between the first suspension beam member and the second suspension beam member. Then, the second suspension receiving beam member is supported by being suspended by both ends, and the suspension supporting position is the central portion in the wall thickness direction of the side wall reinforcing bar portion. With such a structure, since the bottom slab reinforcement is hung while being supported by the first and second suspension beams having high bending rigidity, the bottom slab reinforcement is suppressed from being bent. Further, since the flexure of the bottom slab reinforcement is suppressed, the vertical posture of the side wall reinforcement can be maintained, and the flexure of the side wall reinforcement can also be suppressed.

The second suspension beam member is composed of two channel members symmetrically arranged with their outer web surfaces facing each other, and the first suspension beam member is vertically inserted into the gap between the bottom plate lower reinforcements. It may be fastened to the second suspension beam member with U-shaped bolts whose both ends pass through the gap between the two channel members. In this way, the first suspension beam member and the like can be configured by general-purpose elements such as the channel material and the U-shaped bolt.

Moreover, the hanging device includes a plurality of vertical beam members extending in a direction substantially parallel to the first suspension beam member, and a horizontal beam member extending in a direction substantially orthogonal to the vertical beam member. May be done. According to this configuration, the deformation of the suspending device is suppressed, and the posture of the reinforcing bar cage during the suspension is stable.

ADVANTAGE OF THE INVENTION According to this invention, the suspension method and suspension structure which suppress the bending of a reinforcing-bar cage can be provided.

(A) is a side view of a bridge to which the suspension method and suspension structure of this embodiment are applied, and (b) is a plan view thereof. It is a side view which shows a mobile work vehicle. It is a front view showing the important section of a mobile work vehicle. It is a top view showing the important section of a mobile work vehicle. (A)-(d) is a side view which shows in order the procedure of overhang construction by a mobile work vehicle. (A) is sectional drawing which shows a rebar cage, (b) is sectional drawing which shows the state which attached the jig for suspension to a rebar cage. (A), (b) is sectional drawing which expands and shows the vicinity of the bottom slab reinforcement of a reinforcement cage. It is sectional drawing which expands and shows the intersection part of the bottom slab reinforcement of a reinforcement cage, and a side wall reinforcement. It is sectional drawing which expands and shows the upper vicinity of the side wall reinforcement of a reinforcement cage. (A) is a perspective view showing a single pipe pipe and a bent portion, and (b) is a side view showing the single pipe pipe and a bent portion sandwiched. It is a figure which shows the state in which the rebar cage was hung by the trolley.

Hereinafter, embodiments of a method for suspending a reinforcing bar cage and a suspending structure according to the present invention will be described in detail with reference to the drawings.

First, the suspension method of this embodiment and the overhanging construction method of the bridge 100 to which the suspension structure is applied will be described. The bridge 100 shown in FIG. 1 is a structure made of concrete, for example, a continuous ramen box girder bridge. The bridge 100 includes a plurality of bridge piers 101 standing upright from the ground, a pillar head 103 provided on each bridge pier 101, and a bridge girder 104 bridged between the pillar heads 103 and 103. The bridge girder 104 has two box girders 105 extending substantially parallel to the bridge axis direction, and an overhanging floor slab 107 provided on the box girder 105. In the following description, as shown in the drawings, X, Y, and Z may be used with the vertical direction as the Z direction, the bridge axis direction as the Y direction, and the bridge axis orthogonal direction as the X direction.

As shown in FIG. 3, one box girder 105 extends substantially horizontally at a bottom plate 105a extending substantially horizontally, two webs 105b standing substantially vertically upward from both ends of the bottom plate 105a, and an upper end of the web 105b. And the existing upper plate 105c, and the cross-sectional shape of the box girder 105 orthogonal to the bridge axis direction is a hollow rectangle. The box girder 105 after completion may extend in the horizontal direction or may extend in a direction inclined with respect to the horizontal direction. Further, the box girder 105 after completion may extend straight in a plan view, or may extend curvedly. In this embodiment, as shown in FIGS. 1A and 1B, the case where the completed box girder 105 extends straight in the horizontal direction will be described as an example. Further, as shown in FIG. 1(b), the box girder 105 extends in the direction perpendicular to the bridge axis as the box girder 105 moves away from the column head 103 (the column head 103 on the left side in the figure) that starts the overhanging construction method in the present embodiment. It has been widened.

The box girder 105 is constructed one block at a time from the column head 103 by an overhanging construction method, and gradually extends in the bridge axis direction by one block toward another adjacent column head 103. Actually, the erection erection in two directions is performed from one stilt head 103 in opposite directions, but in the present embodiment, only the construction of erection erection in one direction will be described. Below, the direction in which the box girder 105 is extended by the overhanging construction method is defined as “front”, and words such as front and rear are used.

Further, a portion of one block which is a construction unit of the box girder 105 is referred to as a "box girder block P". Further, when distinguishing each box girder block P, the box girder block P1 of the first block, the second block,... P2,..., Box girder block Pn.

As shown in FIG. 2, a plurality of rails 123 are laid on the upper surface of the existing part of the bridge girder 104 (hereinafter referred to as “bridge girder existing part 104a”), and the rail 123 extends to the front end of the bridge girder existing part 104a. .. A mobile work vehicle 121 used in the overhanging construction method is installed on the rail 123, and the mobile work vehicle 121 is configured to be movable on the rail 123 in the bridge axis direction.

The mobile work vehicle 121 is fixed to the front end of the rail 123, and projects the box girder block Pn from the front end of the existing part of the bridge girder 104a. Then, the rail 123 is extended on the completed box girder block Pn. Then, the mobile work vehicle 121 is moved forward to the tip of the rail 123, and the box girder block P(n+1) is overhanging. By repeating the above, the existing portion of the bridge girder 104a gradually expands.

(Mobile work vehicle)
Next, the mobile work vehicle 121 will be described with reference to FIGS.

As shown in FIG. 2, the mobile work vehicle 121 includes a wagon frame 130 that is movable on the rail 123 in the bridge axis direction, and an upper beam 137 arranged on the wagon frame 130. The wagon frame 130 and the upper beam 137 are formed by joining a plurality of H-shaped steels, for example. In the present specification, the wagen frame 130 is a concept including what is called a “traveler”.

As shown in FIGS. 2 and 3, the wagon frame 130 includes four main frames 131 arranged substantially parallel to each other in the direction perpendicular to the bridge axis. Each main frame 131 is formed of a parallelogram-shaped truss structure surface, and the truss structure surface is arranged along the vertical plane. In the present specification, the main frame 131 is a concept including what is called a “main truss”. A rear end bottom portion of the main frame 131 is fixed to the rail 123 by an anchor jack 133, and a front end bottom portion of the main frame 131 is supported on the rail 123 by a main jack 135.

The upper beam 137 is installed on these four main frames 131. The upper beam 137 includes two horizontal members 137a and 137b extending in a direction perpendicular to the bridge axis and three connecting beams 137c extending in the bridge axis and connecting the horizontal members 137a and 137b. And, and are formed in a cross beam shape. The horizontal member 137a is arranged substantially vertically above the main jack 135. The horizontal member 137b is arranged in front of the front end of the existing portion of the bridge girder 104a. An extension beam 132 that extends further forward is provided at the front end of the upper portion of the main frame 131. A horizontal member 134 extending in the direction perpendicular to the bridge axis is bridged between the two central portions of the four extension beams 132 arranged in the direction perpendicular to the bridge axis.

At the time of overhanging construction, the portion of the main frame 131 in front of the main jack 135 is arranged to extend in front of the front end of the existing portion of the bridge girder 104a. Further, in consideration of the supporting strength of the existing portion of the bridge girder 104a, each main frame 131 is arranged at a position vertically above each web 105b of the box girder 105.

The mobile work vehicle 121 includes a form supporting member 139 that is suspended by the wagon frame 130, and a rebar tip assembly device 141 that is suspended by the upper beam 137 and the horizontal member 134. The formwork support portion 139 is arranged so as to project to the front side of the front end of the existing part of the bridge girder 104a, and the rebar tip assembly device 141 is arranged further forward of the formwork support portion 139.

(Form support part)
The formwork supporting portion 139 has a formwork receiving beam 143 suspended from the upper beam 137 via a plurality of suspending members 142. The formwork receiving beam 143 supports a concrete formwork (not shown) that is assembled in front of the existing part of the bridge girder 104a. By pouring concrete into this concrete formwork, a box girder block Pn for one block is constructed in front of the existing part of the bridge girder 104a. As shown in FIG. 4, corresponding to each of the two box girders 105 to be constructed, the formwork supporting portions 139 are two formworks for the box girder block Pn arranged and arranged in the direction orthogonal to the bridge axis. Support.

(Reinforcing bar tip assembly device)
The rebar tip assembly device 141 has a front work floor 147 suspended from the upper beam 137 and the horizontal member 134 via a plurality of suspension members 145. In the present embodiment, the front working floor 147 is suspended at each of the front ends of the three connecting beams 137c of the upper beam 137, and both ends and the central part of the horizontal member 134 in the direction perpendicular to the bridge axis, at a total of 6 positions. It is suspended and supported via a member 145. On the front work floor 147, the rebar cage 150 is assembled for use in the next box girder block P(n+1). On the front work floor 147, for example, a reinforcing bar ruler is installed as a guide for arranging the reinforcing bars. As shown in FIG. 4, in the rebar preassembly device 141, two rebar cages 150 arranged in the direction perpendicular to the bridge axis are assembled corresponding to each of the two box girders 105 to be constructed.

(Trolley device)
As shown in FIG. 2, the reinforcing bar tip assembly device 141 has a trolley device 151. The trolley device 151 is a device for suspending and moving the rebar cage 150 assembled on the front work floor 147. The trolley device 151 is arranged below the extension beam 132. Further, a sufficient space for assembling and suspending the rebar cage 150 is secured between the trolley device 151 and the front work floor 147. The trolley device 151 includes a trolley rail 153 extending in the bridge axis direction, and a trolley 155 that is guided by the trolley rail 153 to move and that can suspend the reinforcing bar basket 150. By providing such a reinforcing bar tip assembly device 141, in parallel with the work of assembling the form of the box girder block Pn, concrete placing and curing, the assembling work of the rebar cage 150 for the box girder block P(n+1) can be performed. It becomes possible to perform operations such as performing.

(Widening follow-up mechanism)
As described above, each of the four main frames 131 needs to be always arranged on the web of the box girder 105. Since the box girder 105 of the present embodiment gradually widens as the overhanging construction method progresses, the spacing between the webs of the box girder 105 also gradually increases. Therefore, at least two main frames 131 at both ends of the four main frames 131 can be moved in parallel in the direction perpendicular to the bridge axis. Specifically, the movable main frame 131 and the horizontal members 137a and 137b are joined via a slide mechanism 157 (FIG. 3). Then, by the slide mechanism 157, the horizontal members 137a and 137b can be slid relative to the main frame 131 in the direction perpendicular to the bridge axis. With such a mechanism, the position of the main frame 131 in the direction perpendicular to the bridge axis can be made to follow even when the box girder 105 is widened as the erection and erection progresses. Here, it is assumed that the space between the two box girders 105, 105 does not change regardless of the widening of the box girder 105.

(Overhang construction method)
The procedure of the overhanging construction method executed by the mobile work vehicle 121 described above is as follows. As shown in FIG. 5A, the mobile work vehicle 121 is installed above the existing box girder block P(n-1) of the existing part of the bridge girder 104a, and the formwork support 139 is provided for the box girder block Pn. The formwork is assembled, and the concrete of the box girder block Pn is placed on the formwork and cured. A rebar cage for the box girder block Pn is installed in the formwork. In parallel with this work, in the reinforcing bar tip assembly device 141, the reinforcing bar basket 150 for the box girder block P(n+1) is assembled on the front work floor 147.

Thereafter, as shown in FIG. 5B, the box girder block Pn is completed, and the rail 123 is extended on the box girder block Pn. After that, the mobile work vehicle 121 is moved forward and installed above the box girder block Pn. Next, as shown in FIG. 5C, the trolley device 151 lifts the rebar cage 150 on the front work floor 147, and the trolley device 151 suspends the rebar cage 150 to move backward, The rebar cage 150 is installed on the formwork support 139.

After that, as shown in FIG. 5(d), a mold is assembled so as to surround the rebar cage, and a rebar for the upper plate 105c (FIG. 3) is further installed in the mold, and a box is placed in the mold. The concrete of the girder block P(n+1) is poured and cured. In parallel with this work, in the reinforcing bar tip assembly device 141, the reinforcing bar basket 150 for the box girder block P(n+2) is assembled on the front work floor 147. By repeating the above procedure, the box girder block P is formed step by step.

Next, a suspension method and a suspension structure for suspending the rebar cage 150 previously assembled on the front work floor 147 by the trolley device 151 will be described in detail.

(Rebar cage)
As shown in FIG. 3, the box girder block P in which the rebar cage 150 is embedded includes a bottom slab 105a extending along a substantially horizontal plane, and a pair of slabs rising substantially vertically upward from both end edges of the bottom slab 105a and facing each other in the direction perpendicular to the bridge axis. The box girder block P has a hollow rectangular cross section, which is a reinforced concrete structure having substantially parallel webs 105b (side walls).

FIG. 6A is a cross-sectional view of the rebar cage 150, which has a cross section orthogonal to the bridge axis direction. As shown in FIG. 6A, the rebar cage 150 has a substantially U-shaped cross-sectional shape corresponding to the shape of the box girder block P as described above. That is, the reinforcing bar basket 150 includes the bottom plate reinforcing bar portion 11 embedded in the bottom plate 105a (FIG. 3) of the box girder block P and the pair of side wall reinforcing bars embedded in the pair of webs 105b (FIG. 3) of the box girder block P. And a part 13. Although the rebar of the rebar cage 150 preassembled is used for the bottom plate 105a and the web 105b of the box girder block P, the upper plate 105c (FIG. 3) of the box girder block P is made of concrete. The rebar is installed just before.

The bottom slab rebar portion 11 extends along a substantially horizontal plane, and the pair of side wall rebar portions 13 rises substantially vertically upward from both edges of the bottom slab rebar portion 11 in the direction perpendicular to the bridge axis and face each other in the direction perpendicular to the bridge axis. It is provided. The reinforcing bar basket 150 is formed in a basket shape by binding the reinforcing bars extending in the vertical and horizontal directions, which will be described below, with a binding line at the intersection.

The slab bottom reinforcing bars 11 are bottom slab upper bars 15 extending along the upper surface of the bottom slab reinforcing bars 11 in the direction perpendicular to the bridge axis, and bottom slab lower reinforcing bars extending along the bottom surface of the bottom slab reinforcing bars 11 in the direction perpendicular to the bridge axis. 17 and. A large number of bottom slabs 15 and bottom slabs 17 are arranged in parallel in a direction (bridge axis direction) orthogonal to the paper surface of FIG. Further, the bottom slab rebar portion 11 has a plurality of bridge axial rebars 16 that extend in the bridge axis direction directly below the bottom slab upper reinforcement 15 and are bound to each bottom slab upper reinforcement 15 at each intersection. Further, the bottom slab rebar portion 11 has a plurality of bridge axial direction rebars 18 extending in the bridge axis direction directly above the bottom slab bottom bars 17 and bound to the bottom slab bottom bars 17 at each intersection. Both ends of the bottom slab 17 are bent upward along the shape of the lower end of the web reinforcing bar 19 described later.

The side wall reinforcing bar portion 13 includes a web reinforcing bar 19 formed in a U shape in a substantially vertical plane so as to extend along the inner side surface and the outer side surface of the web 105b (FIG. 3). A large number of web reinforcing bars 19 are arranged in parallel to the direction (bridge axis direction) orthogonal to the paper surface of FIG. The web reinforcing bar 19 is embedded along the outer wall surface of the web 105b (FIG. 3) and extends in the substantially vertical direction, and the web rebar 19 is embedded along the inner wall surface of the web 105b (FIG. 3) and in the substantially vertical direction. The inner portion 19b extending to the lower end is connected at the lower end to have a substantially U shape. The upper ends of the web reinforcing bars 19 are respectively bent in the direction perpendicular to the bridge axis toward the outside of the web 105b. The bent portion of the web reinforcing bar 19 is called a bent portion 19c. Further, the side wall reinforcing bar portion 13 has a plurality of bridge axial direction reinforcing bars 20 extending in the bridge axis direction immediately inside the outer side portion 19a of the web reinforcing bar 19 and bound to the outer side portion 19a at each intersection. Further, the side wall reinforcing bar portion 13 has a plurality of bridge axial direction reinforcing bars 22 which extend in the bridge axis direction immediately inside the inside portion 19b of the web reinforcing bar 19 and which are bound to the inside portion 19b at each intersection.

(Reinforcement basket suspension method and suspension structure)
In the reinforcing bar tip assembly device 141 (FIG. 2), when the reinforcing bar basket 150 assembled as described above is suspended by the trolley device 151, the reinforcing bar basket 150 is bent due to its own weight. When the bending of the reinforcing bar basket 150 is large, irreversible deformation is likely to occur particularly in the binding portion between the reinforcing bars, and as a result, the deformation of the entire reinforcing bar basket 150 may remain. Further, the above-mentioned binding portion may be damaged and the binding work may have to be redone. As a measure against this problem, a suspending method and a suspending structure of the rebar cage 150 according to the present embodiment will be described.

FIG. 6B is a cross-sectional view showing a state in which each jig for hanging is attached to the reinforcing bar basket 150 of FIG. 6A. 7: is a figure which expands and shows a part of bottom slab rebar part 11, FIG.7(a) is sectional drawing which took the cross section parallel to a bridge axis right angle direction, FIG.7(b) is a bridge axis. It is sectional drawing which took the cross section parallel to a direction. Further, FIG. 8 is an enlarged cross-sectional view showing a portion where the bottom plate reinforcing bar portion 11 and the side wall reinforcing bar portion 13 in FIG. 6B intersect. Although FIG. 8 illustrates only one of the portions where the bottom plate reinforcing bar portion 11 and the side wall reinforcing bar portion 13 intersect with each other, the other part of the portion also has the same configuration, and thus duplicated illustration is omitted. To do. Further, FIG. 9 is an enlarged cross-sectional view showing the vicinity of the upper end of the side wall reinforcing bar portion 13 in FIG. 6B.

(First suspended beam member)
First, as shown in FIG. 6B and FIG. 7, a plurality of first suspension beam members 21 extending in the bridge axis direction are installed below the bottom slab 17 of the reinforcing bar basket 150. The first suspension beam member 21 has a bending rigidity higher than that of the bottom plate lower reinforcement 17 and the bridge axial direction reinforcement 18, and is, for example, a round steel material. In the example shown in FIG. 6B, seven first suspension beam members 21 are arranged below the bottom slab reinforcement 11. Although the length of the first suspension beam member 21 is not particularly limited, it is preferably a length that traverses under the plurality of bottom plate inversion lines 17. Furthermore, it is preferable that the first suspension beam member 21 traverses under all the bottom slabs 17. Therefore, the length of the first suspension beam member 21 is almost the entire length of the reinforcing bar basket 150 in the bridge axis direction. It is preferable that the length is across.

(Second suspended beam member)
Subsequently, the second suspension beam member 23 extending in the direction perpendicular to the bridge axis is installed above the bottom slab 17 and the bridge axis direction reinforcing bar 18. The second suspension beam member 23 is inserted into the gap between the bridge axial direction reinforcing bar 18 and the bridge axial direction reinforcing bar 16. The one second suspension beam member 23 is composed of two channel members 23a symmetrically arranged with their outer web surfaces facing each other. As a whole, the bottom plate rebar 17 and the bridge axial direction rebar 18 Also has a high bending rigidity. The second suspension beam member 23 is connected to the first suspension beam member 21 with the bottom plate lower reinforcement 17 and the bridge axial direction reinforcing bar 18 interposed therebetween. Specifically, both ends of the U-shaped bolt 27 hooked on the first suspension beam member 21 are inserted into the baskets of the bottom plate lower reinforcement 17 and the bridge axial direction reinforcement 18. Then, both ends of the U-shaped bolt 27 projecting upward from the basket pass through the gap between the two channel members 23a and are hooked on the upper surface of the second suspension beam member 23 by the nut 29 and the hook plate 31. Thus, the first suspension beam member 21 is fastened to the second suspension beam member 23. The fastening portion as described above is formed at each intersection of the first suspension beam member 21 and the second suspension beam member 23.

In the bottom plate rebar portion 11 of the present embodiment, the three second suspension beam members 23 having the above-described configuration are arranged at a predetermined interval in the direction (bridge axis direction) orthogonal to the paper surface of FIG. 6B. To be done. The second suspension beam member 23 exists over almost the entire length of the reinforcing rod basket 150 in the direction perpendicular to the bridge axis, and as shown in FIG. 8, both ends of the second suspension beam member 23 are It is located at a portion where the bottom plate reinforcing bar portion 11 and the side wall reinforcing bar portion 13 intersect.

(Suspension tension material)
Subsequently, as shown in FIGS. 6B and 8, one suspension tension member 35 is connected to each end of each second suspension beam member 23. The suspension tension member 35 extends in a substantially vertical direction between the bridge axial direction reinforcing bar 20 and the bridge axial direction reinforcing bar 22 in the central portion of the side wall reinforcing bar portion 13 in the thickness direction of the web 105b. The lower end of the suspension tension member 35 is inserted into the gap between the two channel members 23a at the end portion of the second suspension beam member 23 in the direction perpendicular to the bridge axis, and the nut 29 and the latch plate 31 are used to form the second suspension beam member. It is hooked on the lower surface of the material 23. The upper end of the suspension tension member 35 is connected to a suspending device 37 described later. The pair of suspension tension members 35 connected to both ends of the one second suspension beam member 23 suspends and supports the one second suspension beam member 23 with both ends. In the rebar cage 150, a total of 6 suspension tension members 35 are installed, and the three second suspension beam members 23 are suspended from both ends and supported.

(Single pipe)
Further, as shown in FIGS. 6B and 9, a pair of upper and lower single-pipe pipes 39 extending in the bridge axis direction and vertically sandwiching the bent portions 19c are installed for the respective bent portions 19c. .. As shown in FIG. 10, holes 39a are formed in the pipe wall of the single pipe 39 at the same arrangement pitch as the web reinforcing bars 19. The holes 39a are shallowly fitted into the side circumferential surfaces of the bent portions 19c of the web reinforcing bars 19, whereby irregular movement of the bent portions 19c in the bridge axis direction is suppressed and the arrangement pitch of the upper end of the web reinforcing bars 19 is reduced. Disturbance is suppressed. Further, each web reinforcing bar 19 is stably clamped at the upper end. The pair of upper and lower single-pipe pipes 39 are connected to a suspending device 37 described later via a U-shaped thin iron plate 41 and slicing bolts 42 provided at both ends of the thin iron plate 41.

(Hanging device)
Subsequently, as shown in FIGS. 6B and 9, with respect to the suspending device 37 disposed above each side wall reinforcing bar portion 13, the upper end of the suspension tension member 35 and the single pipe pipe 39 are provided. , Are fixed. The suspension device 37 has a cross beam structure by a plurality of horizontal beam members 43 extending in the direction perpendicular to the bridge axis and a plurality of vertical beam members 45 joined to the upper surface of the horizontal beam member 43 and extending in the bridge axis direction. Is formed. One horizontal beam member 43 is composed of two square pipes 43a arranged in parallel (see FIG. 11). One vertical beam member 45 is composed of two channel members 45a that are symmetrically arranged with their web outer surfaces facing each other. In the present embodiment, the suspending device 37 is composed of two horizontal beam members 43 and three vertical beam members 45.

A bolt 47 is inserted substantially vertically into the gap between the square pipes 43a of the horizontal beam member 43 and the gap between the channel members 45a of the vertical beam member 45, and the nut 29 and the latch plate 31 are attached to the upper and lower ends thereof, respectively. The horizontal beam member 43 and the vertical beam member 45 are firmly fastened by being tightened. The upper end of the suspension tension member 35 is connected to the suspending device 37 so as to be hooked on the upper surface of the lateral beam member 43 by the nut 29 and the hook plate 31. In addition, the pair of upper and lower single pipes 39 includes a U-shaped thin iron plate 41 and slicing bolts 42 provided at both ends of the thin iron plate 41, and a nut 29 and a locking plate 31 to provide an upper surface of the horizontal beam member 43. It is connected to the suspending device 37 so that it is hooked on.

(Sliding mechanism of sling part)
Further, among the plurality of vertical beam members 45, the vertical beam member 45 positioned directly above the suspension tension member 35 is provided with two device suspension receiving members 51 arranged at predetermined intervals in the bridge axis direction. ing. The device suspension member 51 has, for example, H steel shorter than the channel material 45a, and the web of the H steel is located between the channel materials 45a. Further, the upper and lower flanges of the H steel are hooked on the upper surface and the lower surface of the vertical beam member 45, respectively, so that the vertical movement of the device suspension member 51 with respect to the vertical beam member 45 is restricted. Further, the apparatus steel support member 51 is slidable with respect to the longitudinal beam member 45 in the bridge axis direction at a predetermined stroke by sliding the H steel flange and the web relative to the channel member 45a. Further, the device suspension support member 51 has a sling portion 51a provided on the upper surface of the H steel flange.

FIG. 11 is a view of a state in which the reinforcing bar cage 150 is suspended by the trolley 155 (suspension means), as viewed from the direction perpendicular to the bridge axis. Note that, in FIG. 11, a large number of reinforcing bars constituting the reinforcing bar cage 150 are omitted and only the outline of the reinforcing bar cage 150 is shown as a quadrangle. As shown in FIG. 11, a swivel hook 55 is hooked on each sling portion 51 a, and the swivel hook 55 is connected to the trolley 155 via an electric chain block 57. The rebar cage 150 assembled on the front work floor 147 (FIG. 2) is lifted upward by the electric chain block 57 at the above-mentioned four slings 51a, and hung by the trolley 155 through the electric chain block 57. To be Then, the trolley 155 is guided by the trolley rail 153 and moves in the bridge axis direction, so that the reinforcing bar basket 150 moves in the bridge axis direction.

The operation method and effect of the suspending method and the suspending structure of the reinforcing bar basket 150 described above will be described. In the above-described suspension method and suspension structure, the first suspension beam member 21 and the second suspension beam member 23, which have higher bending rigidity than the bottom slab 17 and the like, are provided along the lower surface of the bottom slab reinforcement 11. The bottom suspension bars 17 and the bridge axial direction reinforcement bars 18 are vertically sandwiched between the first suspension beam members 21 and the second suspension beam members 23. Then, each of the second suspension beam members 23 is hung and supported by both ends, and the hung and supported position is the central portion of the side wall reinforcing bar portion 13 in the wall thickness direction. With such a structure, since the bottom slab rebar portion 11 is hung while being supported by the first suspension beam member 21 and the second suspension beam member 23 having high bending rigidity, the flexure of the bottom slab member 11 is suppressed. .. Further, since the bending of the bottom plate reinforcing bar portion 11 is suppressed, the vertical posture of the side wall reinforcing bar portion 13 is maintained, and the bending of the side wall reinforcing bar portion 13 can also be suppressed.

The second suspension beam member 23 is composed of two channel members 23 a symmetrically arranged with their outer web surfaces facing each other, and the first suspension beam member 21 is a gap between the bottom plate lower bars 17. And is fastened to the second suspension beam member 23 by U-shaped bolts 27 that pass through the gap between the two channel members 23a and are vertically inserted. As described above, the first suspension beam member 21, the second suspension beam member 23, and the like can be configured by general-purpose elements such as the channel member 23a and the U-shaped bolt 27.

The suspending device 37 has a cross beam structure including a plurality of vertical beam members 45 extending in the bridge axis direction and a horizontal beam member 43 extending in a direction orthogonal to the vertical beam members 45. According to this configuration, the deformation of the suspending device 37 itself (in particular, the deformation in the horizontal plane) is suppressed, and the posture of the reinforcing bar basket 150 during the suspension is stabilized.

Further, as another method for suppressing the bending of the reinforcing bar basket 150, it may be considered that a large number of slings are evenly arranged in the reinforcing bar basket 150 in a plan view. However, in this type of mobile work vehicle 121, various structures and devices are often arranged in the space above the rebar cage 150, and a large number of hanging materials can be freely arranged in the space above the rebar cage 150. Often difficult to move. On the other hand, in this type of mobile work vehicle 121, there are relatively few structures and devices arranged in the space vertically above the web 105b of the box girder 105. Therefore, as in the suspending method and the suspending structure of the present embodiment, it is preferable that the sled portions 51a of the reinforcing bar basket 150 are provided concentrated on the side wall reinforcing bar portions 13.

The present invention can be implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the above-described embodiment. In addition, it is possible to configure a modified example of the example by utilizing the technical matters described in the above-described embodiment. The configurations of the respective embodiments may be appropriately combined and used.

For example, in the embodiment, an example in which the present invention is applied to suspending the rebar cage 150 of the previous set in the overhanging construction method is described, but the present invention is not limited to this, and the bottom slab rebar portion and both edges of the bottom slab rebar portion are described. The present invention can be applied to any reinforcing bar basket having a side wall reinforcing bar portion rising from the section. Further, in the embodiment, an example in which the bottom plate 105a of the box girder block P and the bottom plate reinforcing bar portion 11 of the reinforcing bar cage 150 are substantially horizontal has been described, but the present invention is not limited to this, and the bottom plate reinforcing bar portion of the reinforcing bar cage is inclined. You may have. That is, depending on the shape of the bridge girder 104 to be built, the bottom slab 105a and the bottom slab rebar 11 may be inclined with respect to the horizontal plane. In this case, the first suspension beam member 21 is also tilted in accordance with the inclination of the bottom slab reinforcement 11, and the first suspension beam member 21 is laid along the lower surface of the bottom slab 11, so that the suspension is performed in accordance with the embodiment. The hanging method and the hanging structure may be appropriately modified.

Further, in the embodiment, the seven first suspension beam members 21 and the three second suspension beam members 23 are used for one rebar cage 150. It can be changed as appropriate according to the specifications. The number of the first suspension beam members 21 and the second suspension beam members 23 may be either singular, but is preferably plural from the viewpoint of reducing the bending of the rebar cage 150.

11... Bottom plate reinforcing bar part, 13... Side wall reinforcing bar part, 17... Bottom plate lower bar, 21... First suspension beam member, 23... Second suspension beam member, 23a... Channel member, 27... U-shaped bolt, 35... Hanging Tensile material, 37... Suspension device, 43... Horizontal beam material, 45... Vertical beam material, 100... Bridge, 105a... Bottom plate, 105b... Web (side wall), 150... Reinforcing cage, 155... Trolley (hanging means), P: Box girder block (reinforced concrete structure).

Claims (4)

And a bottom slab rebar portion embedded in the bottom slab of the reinforced concrete structure, and a pair of opposing side wall rebar portions each of which is provided so as to stand up from both edges of the bottom slab rebar portion and is embedded in the side wall of the reinforced concrete structure. A method of hanging a rebar basket,
Along the lower surface of the bottom plate reinforcing bar portion, installed below the bottom plate reinforcing bar extending in the opposite direction of the side wall reinforcing bar portion, extending in a direction substantially orthogonal to the bottom plate reinforcing bar, and higher than the bottom plate reinforcing bar. A first suspension beam having bending rigidity;
The first suspension beam, which extends substantially parallel to the extending direction of the bottom slab below the bottom slab, has a bending rigidity higher than that of the bottom slab and sandwiches the bottom slab. A second suspension beam member connected to the member,
In each of the side wall reinforcing bars, the side wall reinforcing bars extend through the central portion of the side wall in the thickness direction to the upper end of the side wall reinforcing bars, and the second suspension beam member is hung from both sides. A pair of suspension tension members that support downwards,
A pair of suspending devices arranged above each of the side wall reinforcing bars and having an upper end portion of the suspension tension member connected thereto are installed,
A suspending method, wherein a pair of the suspending devices are suspended by a predetermined suspending means. The second suspension beam member is composed of two channel members symmetrically arranged with their web outer surfaces facing each other.
The first suspension beam member is vertically inserted into the gap between the bottom slabs, and both ends of the first suspension beam member are fastened to the second suspension beam member by U-shaped bolts that pass through the gap between the two channel members. The suspension method according to claim 1, wherein The hanging device,
The cross beam structure having a plurality of vertical beam members extending in a direction substantially parallel to the first suspension beam member and a horizontal beam member extending in a direction substantially orthogonal to the vertical beam member is formed. Or the suspension method according to 2. And a bottom slab rebar portion embedded in the bottom slab of the reinforced concrete structure, and a pair of opposing side wall rebar portions each of which is provided so as to stand up from both edges of the bottom slab rebar portion and is embedded in the side wall of the reinforced concrete structure. It is a hanging structure of a rebar cage,
Along the lower surface of the bottom plate reinforcing bar portion, installed below the bottom plate reinforcing bar extending in the opposite direction of the side wall reinforcing bar portion, extending in a direction substantially orthogonal to the bottom plate reinforcing bar, and higher than the bottom plate reinforcing bar. A first suspension beam having bending rigidity;
The first suspension beam, which extends substantially parallel to the extending direction of the bottom slab below the bottom slab, has a bending rigidity higher than that of the bottom slab and sandwiches the bottom slab. A second suspension beam member connected to the member,
In each of the side wall reinforcing bars, the side wall reinforcing bars extend through the central portion of the side wall in the thickness direction to the upper end of the side wall reinforcing bars, and the second suspension beam member is hung from both sides. A pair of suspension tension members that support downwards,
A suspending structure comprising: a pair of suspending devices disposed above each of the side wall reinforcing bars, to which the upper ends of the suspension tension members are connected, and which are suspended by a predetermined suspending unit.

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