JP7157092B2 - Construction method of precast concrete structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for constructing a precast concrete structure, and more particularly to a method for efficiently constructing a precast concrete structure by reducing the complexity of the work.

To construct a road bridge, floor slabs, which are precast concrete members, are placed on girders supported by supports such as bridge piers, and concrete is placed between the adjacent slabs to hold them together. A connection method is known (see Patent Documents 1, 2, and 3, for example). Between the opposing ends of the floor slabs to be connected, a large number of reinforcing bars extending toward the opposing opposing ends are arranged at intervals in the width direction of the floor slabs. A large number of rebars arranged side by side in this manner are also arranged in two or more stages at intervals in the vertical direction. After that, many reinforcing bars are embedded in the concrete placed between the opposite ends of the floor slabs, and when this concrete hardens, the adjacent floor slabs are joined together. A floor slab, which is a precast structure, is constructed. Such a joining method may be applied to the precast construction of offshore piers and the construction of floor slabs on beams supported by piles.

When constructing a floor slab, using precast concrete members as floor materials can significantly reduce the number of work steps compared to forming members using cast-in-place concrete. However, it still requires a large number of man-hours to arrange a large number of rebars in the defined space between the opposite ends of the floor material with intervals in the width direction and the vertical direction. Therefore, there is room for improvement in constructing precast concrete structures more efficiently by reducing the complexity of bar arrangement work.

JP 2019-2251 A Japanese Patent Application Laid-Open No. 2019-132070 JP 2019-183425 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for constructing a precast concrete structure more efficiently by reducing the complexity of the work.

In order to achieve the above object, the method for constructing a precast concrete structure according to the present invention comprises placing one precast concrete member and the other precast concrete member facing each other with a gap therebetween, and placing the precast concrete member in the gap. A large number of reinforcing bars extending from each of the opposing ends toward the opposing ends of the opposite sides are laid out at intervals in the horizontal direction, and are spaced apart in the vertical direction. A precast concrete structure in which the precast concrete members are connected and integrated by placing concrete in the gaps and solidifying the concrete in which a large number of the reinforcing bars are embedded. In the construction method of , each of the opposing ends is formed in a step shape having an upper end face and a lower end face projecting in a direction toward the opposing end on the other side from the upper end face, A large number of rebar joints arranged at intervals in the lateral direction are provided on the lower end surface, and a large number of upper rebars arranged at intervals in the lateral direction are attached to each of the upper end surfaces of the mating side. The precast concrete members are protruded in the direction toward the opposing end portions, and the protruding ends are set to an allowable range in which they do not protrude beyond a predetermined length from the lower end surface on their own side, and the respective precast concrete members are joined to the opposing end portions. and then connecting a lower tie bar to each of said rebar connections to extend toward and from said opposite ends of the mating side. In the lower reinforcing bar arrangement work, the upper connecting reinforcing bars are arranged between the upper reinforcing bars extending from the respective upper end surfaces and facing each other. By doing so, it is characterized in that it is performed prior to the upper reinforcing bar arrangement work for connecting the upper reinforcing bars facing each other.

According to the invention, the mutually opposite ends of the respective precast concrete members are stepped with the upper end face and the lower end face. Further, the lower end surface has a large number of reinforcing bar connection portions arranged at intervals in the horizontal direction, and the upper end surface has a large number of upper reinforcing bars arranged at intervals in the horizontal direction. and the projecting end does not protrude from the lower end face on its own side by a predetermined length or more. Therefore, in the gap between the opposing ends, the lower connecting reinforcing bars extending from the opposing ends are arranged in an overlapping state using the respective reinforcing bar connection portions. By performing the work in advance, it is possible to avoid the upper reinforcing bar from becoming an obstacle to the lower reinforcing bar arrangement work. In addition, since the upper reinforcing bar arrangement work for connecting the opposing upper reinforcing bars with the upper connecting reinforcing bar is performed above the already arranged lower connecting reinforcing bar, the lower connecting reinforcing bar becomes an obstacle. You can avoid getting in the way. Therefore, it is advantageous to more efficiently build a precast concrete structure by reducing the complexity of reinforcing bar arrangement work when connecting precast concrete members to each other.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which notches one part of the pier superstructure to which the connection structure of the precast-concrete structure of this invention was applied, and illustrates it by planar view. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; FIG. 3 is an explanatory diagram illustrating an enlarged view of the vicinity of FIG. 2 in a plan view; FIG. 10 is an explanatory diagram illustrating a side view of the periphery of the opposing end of the floor slab unit arranged on the upper surface of the beam; FIG. 5 is a plan view of FIG. 4; It is explanatory drawing which illustrates the state by which the lower side connection reinforcement was arranged by the opposing edge part of FIG. 4 by the side view. FIG. 7 is a plan view of FIG. 6; FIG. 7 is an explanatory view showing, in a side view, a state in which studs protrude from the upper surface of the beam in FIG. 6 and width direction reinforcing bars are arranged in lower reinforcing bars. FIG. 9 is a plan view of FIG. 8; It is explanatory drawing which illustrates the state by which the upper side connecting reinforcing bar was arranged between the upper side reinforcing bars of FIG. 8 by the side view. FIG. 11 is a plan view of FIG. 10; FIG. 11 is an explanatory diagram illustrating, in a side view, a state in which width direction reinforcing bars are arranged on the upper reinforcing bar of FIG. 10 ; FIG. 13 is a plan view of FIG. 12; FIG. 13 is an explanatory view showing, in a side view, a state in which concrete is cast in the gaps between the opposing ends of the floor slab units of FIG. 12 ; FIG. 15 is a plan view of FIG. 14;

Hereinafter, a method for constructing a precast concrete structure and a connection structure thereof according to the present invention will be described based on embodiments shown in the drawings.

Although there are various precast concrete structures to which the present invention is applicable, in this embodiment, a floor slab 3 constituting a pier superstructure 1 as shown in FIGS. 1 to 3 will be described as an example. The floor slab 3 is constructed on beams 2 supported by piles 2a erected on the seabed ground at intervals. In this embodiment, the beams 2 are grid-like in plan view. In some cases, the precast concrete structure (floor slab 3) is constructed simultaneously with the beam 2 while being placed on the ground.

The floor slab 3 comprises a plurality of floor slab units 4 which are precast concrete members, a large number of reinforcing bars 9 and 10 arranged in the gaps between the opposing ends 5 of the respective floor slab units 4, and hammered into the gaps. and a cast-in-place concrete portion 14 in which a large number of reinforcing bars 9, 10 are embedded and solidified. Each opposing end 5 of the floor slab unit 4 rests on the upper surface of the beam 2 supported by the pile 2a. A cast-in-place concrete portion 14 is located above the beam 2 . In the drawing, the longitudinal direction of the floor slab unit 4 is indicated by an arrow L, and the direction perpendicular to the longitudinal direction L is indicated by an arrow W as a width direction. An arrow H indicates the height direction of the floor slab unit 4 .

A large number of lower reinforcing bars 9 extending in the longitudinal direction L are embedded in the floor slab unit 4 at intervals in the width direction W. As shown in FIG. In addition, a large number of upper reinforcing bars 10 extending in the longitudinal direction L are embedded at intervals in the width direction W above the arranged lower reinforcing bars 9 at intervals. Although not shown in FIGS. 1 to 3, a large number of widthwise reinforcing bars extending in the width direction W intersecting the lower reinforcing bars 9 and the upper reinforcing bars 10 are spaced apart in the longitudinal direction L. Buried. In the cast-in-place concrete portion 14, a lower connecting reinforcing bar 9a, an upper connecting reinforcing bar 10, an upper connecting reinforcing bar 11, and width direction reinforcing bars 12a, 12b are embedded. The lower connecting reinforcing bar 9 a is connected to the lower reinforcing bar 9 via a reinforcing bar connecting portion 8 . In addition, the connecting method of reinforcing bars in the cast-in-place concrete portion 14 in the width direction W is also the same. The upper reinforcing bars 10 facing each other in the longitudinal direction L are connected by upper connecting reinforcing bars 11 . The connection structure of the floor slab 3 will be described in detail together with an explanation of an example of the procedure for constructing this floor slab 3. FIG.

In order to construct the floor slab 3, first, using a crane or the like, the opposing ends 5 of the floor slab unit 4 are placed on the upper surfaces of the beams 2 as illustrated in FIGS. A floor slab unit 4 is arranged on the beam 2. - 特許庁As a result, the respective floor slab units 4 are arranged with the opposing ends 5 facing each other with a gap therebetween.

Each opposing end portion 5 of the floor slab unit 4 is formed in a stepped shape having an upper end face 7 and a lower end face 6 projecting in the longitudinal direction L from the upper end face 7 . That is, each lower end face 6 protrudes in the direction toward the opposing end 5 on the other side than the upper end face 7 on its own side. The protruding length of the lower end face 6 from the upper end face 7 varies depending on the diameter (thickness) of the reinforcing bars embedded in the floor slab unit 4, but is, for example, about 50 cm to 100 cm. The gap between the opposing lower end faces 6 is, for example, about 50 cm to 100 cm.

The lower end face 6 is provided with a large number of reinforcing bar connection portions 8 which are arranged in a line at intervals in the width direction W. As shown in FIG. Each reinforcing bar joint 8 is connected to a lower reinforcing bar 9 embedded in the floor slab unit 4 . For example, a known mechanical joint can be used for the reinforcing bar connection portion 8 .

A large number of upper reinforcing bars 10 arranged in a line at intervals in the width direction W protrude in the longitudinal direction L from the upper end face 7 . That is, the upper reinforcing bars 10 embedded in the floor slab unit 4 protrude from the upper end surface 7 and extend in the direction toward the opposite end 5 on the opposite side. The protruding ends of these upper reinforcing bars 10 are set within a range that does not protrude beyond a predetermined length (for example, about 10 cm) in the longitudinal direction L from the lower end face 6 on their side. In this embodiment, the upper reinforcing bar 10 does not extend to the position of the lower end face 6 on its own side, and the projecting end is set at a position slightly retreated from the lower end face 6 in the longitudinal direction L. The protruding end of the upper reinforcing bar 10 can be set at a position that protrudes in the longitudinal direction L from the lower end surface 6 on its own side. Therefore, it is preferable that the protruding end of the upper reinforcing bar 10 does not protrude from the lower end face 6 on its own side, and is set near the lower end face 6, for example.

In this embodiment, a width direction reinforcing bar 12b extending in the width direction W is arranged in advance as a reinforcing reinforcing bar in a portion protruding from the upper end surface 7 of the upper reinforcing bar 10 . The width direction reinforcing bars 12 b can also be arranged after the floor slab unit 4 is arranged on the beam 2 . If the width direction reinforcing bars 12b are arranged before the floor slab unit 4 is placed on the beam 2 as in this embodiment, it is advantageous to reduce the work on the beam 2. That is, the width direction reinforcing bars 12b are preferably laid out in advance in a factory or on-site work yard before arranging the floor slab units 4 with a gap between the opposing ends 5 thereof.

Next, prior to the upper side reinforcement work, the lower side reinforcement work is performed. 6 and 7, in the lower reinforcing bar arrangement work, the lower connecting reinforcing bars 9a are connected to the reinforcing bar connecting portions 8 of the respective floor slab units 4, and the other floor slab unit 4 faces the reinforcing bars. It extends towards the opposite end 5 . As a result, the lower connecting reinforcing bars 9a extending from the reinforcing bar connecting portions 8 of the lower end faces 6 of the respective floor slab units 4 are arranged so as to overlap each other in the longitudinal direction L. A mechanical fixture (for example, an end band that is a diameter expanding member) is attached to the tip of the lower connecting reinforcing bar 9a that is connected to and extends from the reinforcing bar connecting portion 8 . Each lower tie bar 9a is anchored in a cast-in-place concrete section 14. As shown in FIG.

In this embodiment, the facing reinforcing bar connection portions 8 of the floor slab units 4 are arranged to be offset (shifted) in the width direction W. As shown in FIG. Therefore, the bar arrangement work can be performed without interference between the lower connecting reinforcing bars 9a extending from the respective opposite ends 5 and overlapping each other in the longitudinal direction L, which facilitates the work. It is advantageous. The overlap length P between the lower connecting reinforcing bars 9a is, for example, 50% or more and 90% or less of the gap G between the opposing lower end faces 6. As shown in FIG.

Next, as exemplified in FIGS. 8 and 9, in order to ensure the integrity of the beam 2 and the cast-in-place concrete portion 14 on the upper surface of the beam 2, a metal projection such as a stud 13 is driven into the beam 2 as necessary. set up. The studs 13 can be protruded in advance before the lower connecting reinforcing bars 9a are arranged, but by using such a procedure, the studs 13 do not interfere with the already arranged lower connecting reinforcing bars 9a. , the stud 13 can be protruded at an appropriate position. Moreover, when the lower connecting reinforcing bars 9a are arranged, there are no metal protruding objects 13 such as studs 13 or stirrups protruding from the upper surfaces of the beams 2, so there are no obstacles to the movement of workers. Therefore, it is more advantageous to smoothly arrange the reinforcing bars of the lower connecting reinforcing bars 9a.

Further, as reinforcing reinforcing bars, width direction reinforcing bars 12a extending in the width direction W so as to intersect the arranged lower connecting reinforcing bars 9a are arranged at intervals in the longitudinal direction L. The projecting work of the stud 13 can also be performed after arranging the width direction reinforcing bars 12a. When the floor slab units 4 are arranged with a gap between the opposing ends 5 as in this embodiment, the installation surface (upper surface of the beam 2) corresponding to the gap is cast by post-construction. It is desirable that there be no metal projections 13 embedded in the concrete. The studs 13 are preferably protruded between the arrangement of the lower connecting reinforcing bars 9a and the arrangement of the later-described upper connecting reinforcing bars 11. As shown in FIG. Other reinforcing bars are arranged as necessary, and the lower side reinforcement work is completed. Since the lower reinforcing bar arrangement work can be performed in an open space where the upper reinforcing bar 10, the upper connecting reinforcing bar 11, etc. do not exist, the complexity of the work is greatly reduced.

10 and 11, upper connecting reinforcing bars 11 are arranged between the upper reinforcing bars 10 projecting from the upper end faces 7 of the floor slab units 4 and facing each other. . As a result, the upper reinforcing bars 10 protruding from the upper end surface 7 and facing each other are connected to each other via the upper connecting reinforcing bars 11 .

In this embodiment, the upper reinforcing bars 10 connected by the upper connecting reinforcing bars 11 are aligned in the width direction W and the vertical direction H of the floor slab unit 4 . Therefore, the upper connecting reinforcing bars 11 can be easily connected to the respective upper reinforcing bars 10, which is advantageous for smooth bar arrangement work.

Next, as illustrated in FIGS. 12 and 13, width direction reinforcing bars 12b extending in the width direction W so as to intersect the arranged upper connecting reinforcing bars 11 are spaced apart in the longitudinal direction L as reinforcing bars. Arrange the reinforcement. Other reinforcing bars are arranged as necessary, and the upper side reinforcement work is completed.

The lower reinforcement work is performed prior to the upper reinforcement work, but instead of starting the upper reinforcement work after all the lower reinforcement work is completed, may start part of the upper reinforcement work. For example, above the area where the lower tie bars 9a have already been extended, the upper reinforcement work can be started.

Next, concrete is placed in the gaps between the respective opposing ends 5, and as illustrated in FIGS. An upper reinforcing bar 10, an upper connecting reinforcing bar 11, width direction reinforcing bars 12a and 12b, and a stud 13 are embedded in a cast-in-place concrete portion 14.例文帳に追加Concrete to be placed may be of general specifications or may be of special toughened specifications.

By solidifying the cast-in-place concrete portion 14, the facing and adjacent floor slab units 4 are firmly connected and integrated via the cast-in-place concrete portion 14.例文帳に追加The cast-in-place concrete portion 14 is also firmly joined to the beam 2, and the floor slab 3 is constructed on the beam 2. - 特許庁

As described above, the opposing ends 5 of the respective floor slab units 4 are formed in a two-tiered step shape. Furthermore, the lower end face 6 has a large number of reinforcing bar connection portions 8 arranged in the width direction W, and the upper end face 7 has a large number of upper reinforcing bars 10 arranged in the width direction W protruding in the longitudinal direction L. , the protruding end is set to a range that does not protrude beyond a predetermined length from the lower end face 6 on the self side. Therefore, by performing the lower reinforcing work prior to the upper reinforcing work, the upper reinforcing bar 10 can be prevented from becoming an obstacle and interfering with the lower reinforcing work, and the lower reinforcing bar can be arranged smoothly. work can be done. Further, since the upper reinforcing bar arrangement work for connecting the upper reinforcing bars 10 with the upper connecting reinforcing bar 11 is performed above the already arranged lower connecting reinforcing bar 9a, the lower connecting reinforcing bar 9a does not become an obstacle and can be smoothly performed. It can be carried out.

The gap between the opposing ends 5 of the floor slab unit 4 is a limited narrow space, and moreover, arranging a large number of reinforcing bars is a very complicated work. However, according to the present invention, by devising the structure of the facing end portion 5 of the floor slab unit 4 and devising the procedure of the lower reinforcement work and the upper reinforcement work, the floor slab unit can be constructed as described above. The work involved in connecting the slabs 4 to each other is less complicated, and the floor slabs 3 can be constructed more efficiently.

In the embodiment described above, floor slab units 4 having the same shape are connected to each other, but in the present invention, one precast concrete member to be connected may have a different shape from the other precast concrete member. Moreover, the plan view shape of each precast concrete member to be connected is not limited to a rectangle, and various shapes such as a square, other polygons, a circle, and an ellipse can be adopted.

1 Pier superstructure 2 Beam 2a Pile (support)
3 Floor slab 4 Floor slab unit (precast concrete member)
5 Opposing end 6 Lower end face 7 Upper end face 8 Reinforcement joint 9 Lower reinforcing bar 9a Lower connecting reinforcing bar 10 Upper reinforcing bar 11 Upper connecting reinforcing bar 12a, 12b Width direction reinforcing bar (reinforcing bar)
13 stud (metal protrusion)
14 Cast-in-place concrete part

Claims (6)

One precast concrete member and the other precast concrete member are arranged to face each other with a gap, and in the gap, from each of the opposing ends of the precast concrete members, the opposite end of the opposing partner is placed in the gap. A large number of reinforcing bars extending toward the ground are laid out at intervals in the horizontal direction, and after being laid out at intervals in the vertical direction, concrete is poured into the gaps. In a method for constructing a precast concrete structure, the precast concrete members are connected and integrated by solidifying the concrete in which a large number of the reinforcing bars are embedded,
Each of the opposed end portions is formed in a step shape having an upper end surface and a lower end surface projecting from the upper end surface toward the opposed end surface on the other side. A large number of rebar connection portions arranged at intervals in the lateral direction are provided, and a large number of upper rebars arranged at intervals in the lateral direction are provided on the upper end face of each of the rebars, and directed toward the opposite end portion of the other side. set the projecting end to a permissible range in which it does not protrude beyond a predetermined length from the lower end face on its own side,
After placing each said precast concrete member with said gap between said opposite ends of each other, a lower tether rebar is connected to each said rebar connection and extended toward said opposite end of the other side. and the lower connecting reinforcing bars extending from the respective opposing ends are arranged so as to overlap each other, and the lower connecting reinforcing bars are extended from the respective upper end faces to face each other. Construction of a precast concrete structure, characterized in that upper reinforcing bars are arranged between the upper reinforcing bars to connect the opposing upper reinforcing bars to each other, prior to upper reinforcing bars. Method. 2. The method of constructing a precast concrete structure according to claim 1, wherein the respective precast concrete members are arranged above a support standing on the ground with the gap between the opposite ends of each of the precast concrete members. 3. The method of constructing a precast concrete structure according to claim 1, wherein the reinforcing bar joints of the respective precast concrete members are laterally offset from each other. The method of constructing a precast concrete structure according to any one of claims 1 to 3, wherein the opposing upper reinforcing bars of the respective precast concrete members are aligned in the horizontal direction and the vertical direction. When the respective precast concrete members are arranged with the gap between the opposing ends, the installation surface corresponding to the gap is in a state where there is no metal protrusion embedded in the concrete to be placed. The precast according to any one of claims 1 to 4, wherein the metal projection is provided on the installation surface after the lower connecting reinforcing bar is arranged and before the upper connecting reinforcing bar is arranged. A method of constructing a concrete structure. Reinforcing reinforcing bars extending across a number of said upper reinforcing bars of each of said precast concrete members are placed in advance before placing said respective precast concrete members with said gap between said opposite ends of each said precast concrete member. The method for constructing a precast concrete structure according to any one of claims 1 to 5, wherein reinforcing bars are arranged.

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