JP3729890B2 - Single-sided precast concrete underground beam and its components - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a single-sided precast concrete underground beam in a building such as a store, an office, or a warehouse, and a half precast concrete plate that is a constituent member thereof.
[0002]
[Background Art and Problems to be Solved by the Invention]
The concrete underground beam of the conventional construction method is a construction method in which the formwork is assembled at the site and the concrete is placed, so multiple work types such as earthwork, rebar work, formwork are necessary, and loss time between processes is likely to occur, Construction takes time. In addition, it is difficult to ensure the quality of reinforced concrete and the accuracy tends to deteriorate.
[0003]
For this reason, for example, precast concrete underground beams as shown in FIGS. 8A to 8D have been developed and put into practical use. The precast concrete underground beam 40 in FIG. 8A is made of precast concrete for the entire beam. 8B is a hollow three-sided precast concrete underground beam 41 having an open top, and FIG. 8C is a hollow four-sided precast concrete underground beam having no openings on four sides. 42. In the hollow three-side wall type of FIG. 8B, concrete is placed in the hollow portion on the site using both side walls as a mold. The beam 43 in FIG. 8D has a base portion made of a precast concrete plate 43b, and the beam upper portion 43a is driven on site.
[0004]
However, since all of the precast concrete underground beams 40 to 42 in FIGS. 8A to 8C are heavy, a heavy lifting equipment is required for installation on the site, and the lifting machine is used when the site is small. In some cases, the installation location of the equipment cannot be obtained. Further, when joining the main bars 44 of the continuous underground beam to each other, even if it is desired to employ an inexpensive pressure welding joint, the shortening of the main bars 44 due to the pressure welding cannot be allowed, and pressure welding cannot be employed. Therefore, an expensive mechanical joint or a lap joint with a large amount of reinforcing bars must be used, which increases costs. Since the underground beam in FIG. 8D is precast only for the base portion, the same troubles and problems as in the conventional method occur in forming the beam upper portion 43a.
[0005]
The purpose of this invention is that the precast part is relatively light in weight and can be installed with a small lifting machine, and the amount of work for formwork and rebar work is small. It is possible to provide a single-sided precast concrete underground beam that can shorten the construction period on site and can also press the main bar.
[0006]
[Means for Solving the Problems]
The single-sided precast concrete underground beam according to the present invention is provided with a half precast concrete plate constituting one side portion in which the beam is divided along the longitudinal direction, and the reinforcing bars embedded in the remaining portion of the beam are provided with the half precast concrete plate. The remaining part of the beam is cast in place.
On the side opposite to the half precast concrete plate of cast-in-place concrete, a buried mesh form may be used.
Top of Precast concrete panel is a rising wall projecting than the crest of the poured concrete.
Also, provided by arranging a plurality of half-precast concrete panel in a longitudinal direction, but it may also be joined to each other press fittings main reinforcement protruding from the end face of the adjacent Precast concrete panel.
[0007]
[Action]
According to the underground beam of this configuration, the half precast concrete slab can be used as a single-sided formwork, and the concrete can be placed on the spot by simply assembling the other formwork. In addition, since the reinforcing bars for the on-site cast concrete portion are provided in advance in the half precast concrete plate, the work of arranging the bars at the site is not necessary. In this way, the formwork and rebar work on site are reduced, so that it can be manufactured and constructed on site, and the number of work days on site can be shortened. Also, the amount of formwork used is reduced. In addition, accuracy is improved by precasting, and half precast concrete slabs are used, so it is comparatively light and can be constructed with a small lifting machine, and the main bars can be welded together at the joint between beams. .
When a buried mesh formwork is provided on the side opposite to the half precast concrete slab, it is easy to install a separator of the formwork and the work of the formwork is further reduced. Also, concrete curing can be done quickly. When mesh formwork is used, the surface of the concrete becomes uneven and looks bad, but one side of the underground beam is composed of a half-precast concrete slab that gives a clean surface even if left exposed, so this half-precast By using the concrete plate on the exposed surface such as the outdoor side surface, it is possible to improve the workability by using the mesh formwork while ensuring good appearance.
The upper part of the half precast concrete plate is a rising wall that protrudes beyond the top edge of the cast-in-place concrete , so there is no need to place a separate rising wall, and the rising wall is made of a beautiful half precast concrete plate with a precise surface. Can be configured. Since the portion to be the rising wall and the lower portion of the half precast concrete plate may have the same thickness, the half precast concrete plate can be easily manufactured even if the rising wall is provided integrally.
When a plurality of half precast concrete plates are arranged in the longitudinal direction and the main bars protruding from the end faces of the adjacent half precast concrete plates are pressed against each other, the reinforced joint can be made inexpensive. In this case, since the half precast concrete plate is relatively light, it can be moved by the contraction length of the main bar necessary for the pressure welding, and the pressure welding can be realized. In the case of pressure welding of the main bars of the precast concrete plate, it is necessary to simultaneously press all the main bars driven by concrete in order to allow the movement of the precast concrete plate to allow the main bars to contract during the pressure welding. Then, since the split half precast concrete slab is used, only two upper and lower main bars are included, and therefore, the main bar can be pressed simultaneously.
[0008]
Since the half precast concrete plate of the present invention has the reinforcing bars embedded in the remaining part of the beam pre-assembled and protruded, it can save the labor in the construction of the remaining part of the beam in the field and facilitate the construction. . Since only the reinforcing bars protrude, there is little problem of weight increase.
[0009]
【Example】
An embodiment of the present invention will be described with reference to FIGS. This single-sided precast concrete underground beam (hereinafter abbreviated as single-sided PC beam) 1 has a half-precast concrete plate 2 at one side where the beam is split along the longitudinal direction and is embedded in the remaining part of the beam. Reinforcing bars protrude from the half precast concrete 2 and the remaining part of the beam is the cast-in-place concrete 3.
[0010]
The half precast concrete plate 2 is manufactured, for example, as shown in FIG. That is, upper, lower, left and right mold frames 4A and 4B are assembled on a surface plate (not shown), and reinforcing bars are arranged inside thereof. In this case, among the reinforcing bars embedded in the entire beam, the reinforcing bars embedded in the half precast concrete plate 2 are located within the height surrounded by the molds 4A and 4B, and are embedded in the remaining part of the beam. The bars are arranged so that the portions protrude upward from the molds 4A and 4B. Thereafter, the concrete 5 is placed inside the molds 4A and 4B, and the concrete surface is pressed flat with a wooden trowel or the like.
[0011]
In the half precast concrete plate 2 formed in this way, among the main bars driven into the entire beam, some upper reinforcing bars 6A, some lower reinforcing bars 7A, and one side 8a of the stirrup 8 are provided. Then, the horizontal stripe 9 and one end of the width stop stripe 10 are driven. Further, the remaining portion 8 b of the stirrup 8, the width stop bars 10, and the like are protruded from the half precast concrete plate 2 as reinforcing bar portions to be driven into the remaining portion of the beam. The remaining upper end stripes 6B and 6C, the remaining lower end stripes 7B and 7C, and the remaining lateral stripes 9 are assembled to the remaining portion 8b of the stirrup 8 and the width stop stripes 10 and the like. Here, the upper part of the half precast concrete plate 2 is formed to be a rising wall that protrudes from the top edge of the cast-in-place concrete 3. When the half precast concrete plate 2 is manufactured, a plurality of nuts 11 for screwing a separator 13 to be described later are embedded on the side surface facing the cast-in-place concrete 3 as shown in FIG. The hanging hook 12 is planted as in 1 (B).
[0012]
1A and 1B show a cross-sectional view and a perspective view when the single-sided PC beam 1 is installed on the site. A crushed stone 15 is laid on the bottom surface of the underground beam pit 14 excavated in the ground G at the site, and a discarded concrete 16 is placed. A plurality of rollers 17 are arranged on a half PC plate installation portion on the discarded concrete 16. The half precast concrete slab 2 is placed on the roller 17 in accordance with the ground ink 18 that has been inked on the discarded concrete 16 in advance. At this time, the half precast concrete plate 2 is held in a vertical posture by the beam support jig 19. The beam support jig 19 includes a mounting bracket 20 that holds the upper end of the half precast concrete plate 2, and connecting bars 23 </ b> A and 23 </ b> B that connect the mounting bracket 20 to a pile 21 via a turnbuckle 22. The pile 21 is driven into the ground G in the vicinity of the pit 14. In this manner, the main bars 6A and 7A protruding from the end face of the half precast concrete plate 2 are joined to the main bars 6A and 7A of the adjacent half precast concrete plate 2 by the pressure welding joint 34 in a state in which the half precast concrete plate 2 is prevented from falling. . In addition, when the joining by the pressure welding joint 34 is unnecessary, the said roller 17 is unnecessary.
[0013]
Next, the installation of the half precast concrete plate 2 is adjusted with the turnbuckle 22 of the beam supporting jig 19 and the height of the half precast concrete plate 2 is adjusted with the jack bolt 24 attached to the lower part of the half precast concrete plate 2. Do. Thereafter, the roller 17 is removed from under the half precast concrete plate 2 and a mold 25 corresponding to the height of the ground G is provided on the side surface opposite to the half precast concrete plate 2. As the mold 25, a metal mold, a resin mold, a wooden mold, or the like can be used, but here a mesh mold is used.
The mesh formwork 25 is installed by using a separator 13 that is screwed and connected to the nut 11 embedded in the half precast concrete plate 2. The mesh mold 25 is obtained by lath processing (processing into an expanded metal shape) of a thin plate such as a steel plate, and a commercially available product can be used. By means of a foam tie 26 connected to the tip of the separator 13, vertical and horizontal holding bars 27 </ b> A and 27 </ b> B made of pipes or the like are pressed against the outer surface of the mesh mold 25 to support the mesh mold 25. Thereafter, concrete is placed in a space between the half precast concrete plate 2 and the mesh formwork 25. The mesh mold 25 and the separator 13 are buried in the cast-in-place concrete 3 and only the holding bars 27A and 27B are removed in the mold disassembly work. As described above, when the mesh mold 25 is used as a mold on one side for placing the cast-in-place concrete 3, surplus water after the concrete is poured is drained in a short period of time, and better concrete comes out.
[0014]
FIGS. 3A and 3B are a plan view and a side view showing an example of a joint structure between the single-sided PC beam 1 and the cast-in-place column base. The column base 30 has a base portion 31a of the footing 31 placed in advance, and the half precast concrete plate 2 is horizontally mounted on the base portion 31a. Among the main bars 6A to 6C and 7A to 7C of the single-sided PC beams facing each other across the column mold 32 serving as a column forming space, the upper bar 6A and the lower bar 7A of the half precast concrete plate 2 are connected by a pressure joint 34. Join. Further, the opposing main bars 6B, 6C, 7B, and 7C of the beam portion that becomes the cast-in-place concrete 3 can be formed by lap joints. At the time of joining the pressure welding joint 34, it is necessary to push and move the half precast concrete plate 2 to the pressure welding side as indicated by an arrow P in FIG. Since the beam 1 is relatively light, the pressure welding operation can be easily performed. Moreover, since the main muscles 6A and 7A to be pressure-contacted are only two in the upper and lower directions, the pressure-contact can be performed simultaneously.
After the bar arrangement is completed in this way, concrete is placed on the remaining portion of the column mold 32 and the single-sided PC beam 1 that will become the cast-in-place concrete 3.
[0015]
In place of the press-fit joint 34 or the lap joint, anchor portions 6a are provided in the column mold 32 on the main reinforcing bars 6A to 6C and 7A to 7C as in the example of FIG. 4 to fix the column base 30 in the concrete. You may make it ensure length.
[0016]
FIG. 5 is a side view showing an example of a joining structure when a plurality of the single-sided PC beams 1 are arranged in the longitudinal direction and joined together. In this case as well, in the same manner as in FIG. 3, the upper and lower main bars 6A and 7A protruding from the end of the half precast concrete plate 2 are joined together by the pressure-welding joints 34, and the upper and lower parts of the beam portion to be the in-situ concrete 3 The main bars 6B, 6C, 7B, and 7C are joined by a lap joint or the like.
[0017]
FIG. 6 is a cross-sectional view of an example in which the soil concrete 35 is placed on the spot cast concrete 3 of the single-sided PC beam 1. In this example, when the reinforcing bar 36 embedded in the interstitial concrete 35 is arranged, the end falling portion 36a of the reinforcing bar is inserted into the placement space of the in-situ concrete 3 of the single-sided PC beam 1, and then the in-situ concrete 3 The portion of the concrete and the portion of the soil concrete 35 are placed simultaneously. In addition, this concrete placement is performed after the pit 14 (FIG. 1) is backfilled and the embedding of Ga between the soil is performed.
[0018]
FIG. 7 is a cross-sectional view showing an example in which a floor slab 37 is mounted on the upper end of the single-sided PC beam 1. In this example, after placing the cast-in-place concrete 3 of the single-sided PC beam 1, a crushed stone 38 is laid on the ground G over the upper surface of the cast-in-place concrete 3, and a floor slab 37 is formed on the crushed stone 38. The upper part of the single-sided PC beam 1 that protrudes from the top edge of the cast-in-place concrete 3 of the half precast concrete plate 2 is a rising wall around the building.
[0019]
【The invention's effect】
The single-sided precast concrete underground beam of the present invention is provided with a half precast concrete plate that constitutes one side part with the beam split, and this half precast concrete plate is assumed that a reinforcing bar embedded in the remaining part of the beam protrudes, Since the remaining portion is made of cast-in-place concrete, the half-precast concrete plate can be used as a single-sided formwork, and further, the reinforcement of the cast-in-place concrete portion is provided in advance. Therefore, the amount of formwork used is small, and it can be constructed with high accuracy and in a short construction day without requiring a professional job. Further, since the weight of the precast plate is relatively light, it is possible to work with a small lifting machine, and it is possible to press the main bars at the joint of beams.
In addition, since the upper part of the half precast concrete plate is a rising wall that protrudes from the top of the cast-in-place concrete, there is no need to place a separate rising wall, and it is possible to start with a beautiful half precast concrete plate with a precise surface. A wall can be constructed.
In the case of the underground beam of the invention of claim 2, since the mesh formwork buried on the side opposite to the half precast concrete plate of the cast-in-place concrete is used, the formwork is further simplified and the formwork is dismantled. Since it does not take time, the construction period can be greatly shortened.
For underground beam of the invention of claim 3, since joining the main reinforcement of the half precast concrete panel with pressure, that Do allow rebar bonding low cost.
[Brief description of the drawings]
FIG. 1A is a longitudinal sectional view showing a single-sided precast concrete underground beam according to an embodiment of the present invention, and FIG. 1B is a perspective view showing a joint structure of the underground beam.
FIG. 2 is a perspective view showing a process for producing a half precast concrete plate of the underground beam.
FIGS. 3A and 3B are a plan view and a side view showing an example of a joint structure between the underground beam and the column base. FIG.
FIGS. 4A and 4B are a plan view and a side view showing another example of the joint structure between the underground beam and the column base. FIG.
FIG. 5 is a side view showing an example of a joining structure for joining the underground beams in the longitudinal direction and joining them.
FIG. 6 is a longitudinal sectional view showing a structure in which soil concrete is provided up to the upper end of the underground beam.
FIG. 7 is a longitudinal sectional view showing a structure in which a floor slab is mounted on the upper end of the underground beam.
8A to 8D are cross-sectional views showing respective conventional examples.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Single-sided precast concrete underground beam, 2 ... Half precast concrete slab, 3 ... Cast-in-place concrete, 6A-6C ... Top bar, 7A-7C ... Bottom bar, 25 ... Mesh formwork

Claims (3)

A half precast concrete plate that constitutes one side of the beam that is split along the longitudinal direction is provided, and this half precast concrete plate has a reinforcing bar embedded in the remaining part of the beam, and the remaining part of the beam Single-sided precast concrete underground beam that is cast concrete and the upper part of the half precast concrete slab becomes a rising wall that protrudes from the top of the cast-in-place concrete.   The single-sided precast concrete underground beam according to claim 1, wherein a buried mesh form is provided on a side surface opposite to the half precast concrete plate of the cast-in-place concrete.   The single-sided precast concrete underground beam according to claim 1 or 2, wherein a plurality of half precast concrete plates are provided side by side in the longitudinal direction, and main bars protruding from end faces of adjacent half precast concrete plates are pressed against each other.

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