JP2021042620A - Concrete building and its construction method - Google Patents

Abstract

To provide a concrete building including a PCa concrete wall which places concrete constructing a slab or a beam, and thereby discharges air in a shear cotter recessed in a bottom part of the PCa concrete wall without requiring a work other than the placing work, and joins the wall to the slab or the beam through the shear cotter.SOLUTION: Concrete buildings (1 and 51) have a slab (4) or a beam (3), and a wall (5) that has a first surface (12) and a second surface (13) parallel to a main surface and stands from the slab or the beam, in which the wall at least partially includes a PCa concrete wall (10), the PCa concrete wall has a plurality of shear cotters (14) recessed in a bottom part, each of the plurality of shear cotters is opened to only one of the first surface and the second surface, and the plurality of shear cotters are alternately arranged on the first surface side and the second surface side in a wall length direction, and the lower end of the PCa concrete wall is embedded in the slab or the beam.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a concrete building and its construction method, and more particularly to a concrete building having a slab or a beam and a wall rising from the slab or a beam and a construction method thereof.

A building having a seismic wall structure constructed by using a precast concrete wall is known (for example, Patent Document 1). This building is equipped with a column-beam frame made of concrete columns and beams, and a precast concrete seismic wall arranged in the column-beam frame. Recesses (shear cottas) are formed horizontally at equal intervals on the side surfaces of the columns and the upper and lower end surfaces of the beams. In addition, recesses are similarly formed on the side surfaces of the earthquake-resistant wall and the upper and lower end surfaces. The seismic wall is arranged with a gap between the column and the beam in the column-beam frame so that the concave portion faces the concave portion of the column and the beam, and the column is filled with a grout material (shear key). It is fixed to the beam frame. The recesses of the shear wall, the recesses of the columns and beams, and the grout material filled in these recesses function as shear connectors for transmitting shear force between the columns and beams and the shear walls.

Buildings of other structures constructed using precast concrete walls are also known (eg, Patent Document 2). This building has a column-beam frame of PCa concrete columns and PCa concrete beams and a plurality of PCa concrete wall panels joined in the plane thereof. The PCa concrete wall panel includes aggregated horizontal and aggregated vertical bars as aggregated reinforcing bars arranged around the PCa concrete wall panel. The aggregated horizontal bars are arranged substantially horizontally on the upper side and the lower side inside the PCa concrete wall panel, and project outward from the left and right end faces of the PCa concrete wall panel. The aggregated vertical bars are arranged substantially vertically on the left and right outside of the PCa concrete wall panel, and have an extension that can be fixed to the PCa concrete beam. From the PCa concrete column, the aggregated horizontal bars corresponding to the aggregated horizontal bars of the PCa concrete wall panel protrude. In the space surrounded by the PCa concrete columns, the PCa concrete wall panels, and the PCa concrete beams, cast-in-place concrete is cast after the intensive reinforcing bars are arranged. As a result, the columns and beams and the PCa concrete wall panel are joined. Further, the PCa concrete wall panel is installed directly on the PCa concrete beam. Alternatively, the PCa concrete wall panel is fixed to the PCa concrete beam by using a mortar or grout. In this case, the surface of the PCa concrete wall panel and the PCa concrete beam in contact with the mortar or grout is roughened.

JP-A-2017-206844 JP-A-2009-293347

When the earthquake-resistant wall structure described in Patent Document 1 is constructed of cast-in-place concrete, filling of the cotter with grout material is performed separately from placing concrete on the beam. Therefore, in order to fill the cotter, a work different from the concrete placing is required. In addition, when filling the cotter provided on the lower surface of the precast concrete wall with grout material, an air bleeding hose for entraining the air inside the cotter to the outside is attached to the precast concrete wall to ensure that the air is entrained. It is necessary to confirm. Therefore, the production of the precast concrete wall and the grout filling work in the cotter become complicated. Further, even if an air bleeding hose is used, it is difficult to confirm that there is no air pool in the entire area inside the cotter.

Patent Document 2 describes that the bottom of a PCa concrete wall panel is roughened and fixed to a mortar or grout. In this work, work other than concrete placing work such as mortar laying work and grout injection work is required.

In view of the above background, in the present invention, in a concrete building including a PCa concrete wall, by placing concrete for constructing a slab or a beam, the PCa concrete wall does not require any other work. The subject is to exhaust the air in the shear cotter recessed in the bottom and join the wall to the slab or the beam through the shear cotter.

In order to solve such a problem, an embodiment of the present invention has a slab (4) or a beam (3) and a first surface (12) and a second surface (13) parallel to the main surface. A concrete building (1, 51) having the slab or a wall (5) rising from the beam, wherein the wall includes at least a part of a PCa concrete wall (10) and the PCa concrete wall is at the bottom. It has a plurality of recessed shear cotters (14), each of the plurality of shear cotters is open to only one of the first surface and the second surface, and the plurality of shear cotters have a length of the wall. It is alternately arranged on the first surface side and the second surface side in the direction, and the lower end of the PCa concrete wall is embedded in the slab or the beam.

According to this configuration, since a plurality of sheacotters are open to only one of the first surface and the second surface of the wall, concrete for constructing a slab or a beam is placed so that the lower end of the PCa concrete wall is buried. Then, the air in the sheacotter is discharged to the outside from the open end face, and the sheacotter is filled with concrete. Therefore, by placing concrete, the air in the shear cotter recessed in the bottom of the PCa concrete wall is exhausted without any additional work, and the wall and the slab or beam are joined via the shear cotter. can do. Further, a plurality of sheacotters opened only on one of the first surface and the second surface of the wall are alternately arranged. As a result, in-plane direction (PCa concrete wall length direction) and between the wall and the slab or beam, as compared with the case where only the shear cotter opened toward the first surface of the wall is arranged. The shear force in the out-of-plane direction (the width direction of the PCa concrete wall) is transmitted almost evenly. Therefore, the shear force in the in-plane direction can be efficiently transmitted to the shear cotter.

In the above configuration, the upper surface of the shear cotter may have a slope that increases toward the first surface or the second surface on which the shear cotter is opened.

According to this configuration, when the shear cotter is filled with concrete, the concrete in the shear cotter rises along the slope of the upper surface of the shear cotter, so that the air in the shear cotter is taken to the outside by the concrete. Therefore, it is possible to make it difficult for an air pool to be generated in the shear cotter. Therefore, concrete and sheacotter can effectively transfer the shear forces between the slab and the wall against each other.

In the above configuration, the area of the shear cotter on the bottom surface of the PCa concrete wall is preferably 40 to 60% of the area of the bottom surface.

According to this configuration, the ratio of the area of the shear cotter and the area of the PCa concrete is approximately 1: 1 on the bottom surface of the PCa concrete wall. As a result, both the concrete in the shear cotter and the shear failure at the lower end of the PCa concrete wall are less likely to occur. Therefore, shear failure of the shear connector is less likely to occur.

In the above configuration, the shear cotter may have a tapered shape that extends toward the first surface or the second surface on which the shear cotter is opened.

According to this configuration, when the wall is viewed from the front, the inside of the sheacotta can be easily seen to the back. This makes it possible to visually confirm whether or not the inside of the shear cotter is filled with concrete. Further, since the open end face of the shear cotter is widened, the air in the shear cotter is easily taken. Therefore, it becomes easy to confirm that the air in the shear cotter has been released. Therefore, the workability of the work of joining the wall and the slab or the beam is improved.

In the above configuration, the PCa concrete wall may further have a connecting groove (20) connecting the two shear cotters adjacent to each other.

According to this configuration, when one of two adjacent shear cotters is filled with concrete, the air in the shear cotter is taken to the other shear cotter. As a result, air pools in the shear cotter are less likely to occur.

In order to solve such a problem, another embodiment of the present invention has a slab (4) or a beam (3) and a first surface (12) and a second surface (13) parallel to the main surface. A method of constructing a concrete building (1, 51) having a wall (5) rising from the slab or the beam, which is open to only one of the first surface and the second surface of the wall. A step of manufacturing a PCa concrete wall (10) having a plurality of shear cotters (14) alternately arranged on the first surface side and the second surface side in the length direction at the bottom, and constructing the slab or the beam. A step of arranging the reinforcing bars (17, 35, 36, 37) in the area to be laid (FIG. 8), and a step of building the PCa concrete wall at a predetermined position on the reinforcing bar (FIG. 9). It includes a step (FIG. 11) of placing concrete (15) in the area where the slab or beam is to be constructed so that the lower end of the PCa concrete wall is embedded in the slab or beam.

According to this configuration, since a plurality of shear cotters provided at the bottom of the PCa concrete wall are open to only one of the first surface and the second surface of the wall, the vibrator used when placing concrete is used in the shear cotter. The air pool can be discharged from the inside of the sheacotter. This fills the sheacotta with concrete by placing concrete in the area where the slab or beam will be constructed. Therefore, it is not necessary to bury the shear cotter recessed in the bottom of the PCa concrete wall with mortar, grout, or the like, or to attach an air bleeding hose. Therefore, by placing the concrete to build the slab or beam, the wall and the slab or beam can be joined via a shear cotter recessed in the bottom of the PCa concrete wall without the need for additional work. Can be done.

In the above configuration, the wall further comprises a cast-in-place portion (11) constructed of cast-in-place concrete, the method of which is around the PCa concrete wall after the step of building the PCa concrete wall (FIG. 9). To construct the cast-in-place portion after the step of arranging the wall reinforcements (33, 34) used for the cast-in-place portion (FIG. 10) and the step of placing concrete on the slab or the beam (FIG. 11). It is preferable to further include a step of assembling the wall formwork (40) (FIG. 12) and a step of placing concrete inside the wall formwork (FIG. 14).

According to this configuration, since the wall includes the PCa concrete wall and the cast-in-place portion, the cast-in-place portion can be added to the PCa concrete wall as needed to extend the wall. Thereby, a cast-in-place portion can be added between the PCa concrete walls to construct a long wall in the in-plane direction. Therefore, by using at least one PCa concrete wall for a wall that is long in the in-plane direction, part of the work of arranging the wall reinforcements for constructing the wall and the work of assembling the formwork are omitted, and the concrete construction The construction period for constructing the building can be shortened.

In the above configuration, the step of arranging the reinforcing bar (FIG. 8) may include arranging the half PCa plate (16) below the region where the slab or the beam is constructed.

According to this configuration, half PCa plates can be used as an alternative to at least some of the reinforcing bars and formwork for constructing slabs or beams. This makes it possible to simplify the work of arranging the reinforcing bars of the slab or the beam and the work of assembling the formwork of the slab or the beam. Therefore, the construction period for constructing a concrete building can be shortened.

As described above, according to the present invention, in a concrete building including a PCa concrete wall, a sheacotter recessed in the bottom of the PCa concrete wall by placing concrete without requiring another work. The air inside can be exhausted and the wall can be joined to the slab or beam via a sheacotter.

Cross-sectional view of the building in the direction between beams showing the intermediate floor of the building according to the first embodiment. Front sectional view of the joint between the PCa concrete wall and the beam Sectional view taken along line III-III of FIG. (A) Bottom view of the PCa concrete wall showing the arrangement and shape of the shear cotter according to the first embodiment, and (B) to (E) Bottom view of the PCa concrete wall showing the other arrangement and shape of the shear cotter. (A)-(E) Bottom view of a PCa concrete wall showing the arrangement and shape of the shear cotter connected by the connecting groove. Cross-sectional view of the building under construction in the direction between beams Sectional view taken along the line VII-VII of FIG. Explanatory drawing of the building construction procedure according to the first embodiment Explanatory drawing of the building construction procedure according to the first embodiment Explanatory drawing of the building construction procedure according to the first embodiment Explanatory drawing of the building construction procedure according to the first embodiment Explanatory drawing of the building construction procedure according to the first embodiment Explanatory drawing of the building construction procedure according to the first embodiment Explanatory drawing of the building construction procedure according to the first embodiment Cross-sectional view in the beam-to-beam direction in the building according to the second embodiment Cross-sectional view of the joint between the PCa concrete wall and the beam according to another embodiment Cross-sectional view of the joint between the PCa concrete wall and the slab according to another embodiment.

<< First Embodiment >>
Hereinafter, the building 1 according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the building 1 according to the present embodiment is a reinforced concrete plate-shaped multi-story building. The building 1 includes a pair of columns 2 arranged in the direction between the beams, a plurality of beams 3 provided on each floor so as to connect the pair of columns 2, and a plurality of columns provided on each floor so as to be supported by the beams 3. The slab 4 and a plurality of walls 5 forming a seismic wall constructed on the frame surface of each floor composed of a pair of columns 2 and a pair of upper and lower beams 3 are included. The beam 3 is formed as a wall beam at the upper end of the wall 5 to have the same thickness as the wall 5. The plurality of walls 5 are provided at the same position in a plan view, and form a multi-story shear wall. The slab 4 is joined to the upper end of the beam 3 on the corresponding floor, and the wall 5 on each floor is constructed on the beam 3 and rises from the slab 4. Building 1 further has beams and walls in the girder direction, but these are not shown.

The pillar 2 in this embodiment is constructed of cast-in-place concrete. The wall 5 includes at least a part of the PCa concrete wall 10 (hereinafter referred to as the PCa wall 10), and the portion other than the PCa wall 10 is constructed of cast-in-place concrete. Hereinafter, the portion of the wall 5 constructed by placing concrete on site is referred to as an on-site wall 11. In the present embodiment, the wall 5 is composed of five PCa walls 10 and six cast-in-place walls 11. The PCa walls 10 are arranged between a pair of pillars 2 at intervals with respect to the pillars 2 and at intervals with each other. The cast-in-place wall 11 is constructed between the pillar 2 and the PCa wall 10, or between a pair of PCa walls 10 adjacent to each other. The main surface of the wall 5 is along the paper surface of FIG. 1, and the wall 5 has a first surface 12 and a second surface 13 parallel to the main surface (see FIG. 3). Hereinafter, the left-right direction (in-plane direction) and the front-back direction (out-of-plane direction) will be defined and described with reference to the case where the first surface 12 of the wall 5 is viewed from the front.

As shown in FIGS. 2 and 3, the PCa wall 10 has a plurality of shear cotters 14 recessed in the bottom thereof. Each of the plurality of shear cotters 14 is open to one of the first surface 12 side and the second surface 13 side of the PCa wall 10 (see FIG. 4). The sheacotter 14 is filled with concrete 15 to be cast when the slab 4 is constructed. The upper surface of the shear cotter 14 has a slope that increases toward the surface on which the shear cotter 14 is opened. A plurality of shear cotters that are not open to either the first surface 12 or the second surface 13 are recessed in the center of the upper surface and the end surface of the PCa wall 10 in the thickness direction (not shown).

In this embodiment, the slab 4 has a half PCa plate 16 under it. On the PCa wall 10 and the half PCa plate 16, there are reinforcing bars 17 (see FIGS. 6 and 7) of the slab 4 and the beam 3 and a spacer 18 for placing the PCa wall 10 at a position avoiding the reinforcing bars 17. Have been placed. Before placing the concrete 15, the PCa wall 10 is built on the half PCa plate 16 via the spacer 18 so that the uppermost position of the shear cotter 14 is equal to or lower than the upper surface of the slab 4. In the present embodiment, the uppermost position of the shear cotter 14 is below the upper surface of the slab 4 and substantially the same as the upper surface of the slab 4. The lower end of the PCa wall 10 is buried in the slab 4 when the concrete 15 is poured. Therefore, when the concrete 15 is cast, the inside of the shear cotter 14 is filled with the concrete 15. The concrete 15 filled in the shear cotter 14 becomes a shear key, and the shear key and the concrete 15 at the lower end of the PCa wall 10 function as a shear connector that transmits a shear force to each other.

The spacer 18 may be a resin block or a metal block. Alternatively, the spacer 18 may be a concrete protrusion formed integrally with the PCa wall 10 and protruding from the PCa wall 10, or a bolt screwed into a nut embedded in the PCa wall 10. When the spacer 18 is a bolt, the horizontal accuracy of the PCa wall 10 can be adjusted by adjusting the screwing amount of the bolt.

As shown in FIG. 4A, the plurality of shear cotters 14 are arranged in the left-right direction at the bottom of the PCa wall 10, and are alternately arranged on the first surface 12 side and the second surface 13 side in the left-right direction. ing. The plurality of shear cotters 14 provided on the first surface 12 side are arranged at intervals in the left-right direction, and the shear cotter 14 on the second surface 13 side is arranged at the center in the left-right direction of the two shear cotters 14 adjacent to each other. ing. The planar shape of the shear cotter 14 on the bottom surface of the PCa wall 10 may be a tapered shape that extends toward a surface opened from the inside (the wall core side of the PCa wall 10). The planar shape of the shear cotter 14 according to the present embodiment is a trapezoid that expands toward an end face opened from the inside. The plurality of shear cotters 14 have the same shape and are formed so as to extend from the open end face to the wall core.

The shear cotter 14 may have another shape. For example, as shown in FIG. 4B, the area of one shear cotter 14 can be reduced and the number of shear cotters 14 can be increased. Further, as shown in FIG. 4C, the planar shape of the shear cotter 14 may be a substantially circular shape having a center provided on the wall core side from the open end face. Further, as shown in FIG. 4D, the planar shape of the shear cotter 14 may be a semicircular shape that opens toward the open end face. Further, as shown in FIG. 4E, the planar shape of the shear cotter 14 may be a substantially regular triangular shape in which one side is in contact with an open surface. The area of the shear cotter 14 is preferably 40 to 60% of the area on the bottom surface of the PCa wall 10.

As shown in FIG. 5, in another embodiment of the present invention, the PCa wall 10 further has a connecting groove 20 at the bottom thereof for connecting a plurality of shear cotters 14. The connecting groove 20 is provided so as to connect the points of the two shear cotters 14 adjacent to each other that are closest to each other. The depth of the connecting groove 20 is equal to the depth of the shear cotter 14 (the height of the shear cotter 14 when the first surface 12 of the wall 5 is viewed from the front) at the portion where the connecting groove 20 and the shear cotter 14 are connected to each other. .. Further, the connecting groove 20 may be further provided at a position for connecting the shear cotter 14 located on the end surface side of the wall 5 and the end surface of the wall 5. The connecting groove 20 is filled with the concrete 15 when the concrete 15 constituting each upper portion of the slab 4 and the beam 3 is cast.

FIG. 6 is a cross-sectional view of the building 1 in the middle of construction in the direction between the beams, and the construction of the lower floor and the middle floor is completed, and the upper floor is constructed. Further, in FIG. 6, the arrangement of the reinforcing bars of the walls 5, columns 2 and slabs 4 on the constructed lower floors and intermediate floors is transparently shown. As described above, the wall 5 includes the PCa wall 10 and the in-situ wall 11. The area where the cast-in-place wall 11 is constructed includes the upper surface of the lower slab 4, the lower surface of the area where the upper slab 4 is constructed, the side surface of the pillar 2, the end surface of the PCa wall 10 which opposes the side surface, or the adjacent 2 It is defined by each of the opposing end faces of the PCa walls 10. One end of the half PCa plate 16 is placed on the upper surface of the wall 5. The half PCa version 16 extends in the front-rear direction.

The PCa wall 10 has panel reinforcing bars (not shown) inside the wall 10 for preventing cracks and the like, which are arranged in a grid pattern in the vertical and horizontal directions. The pillar 2 has a large-diameter main bar 30 and a small-diameter hoop bar 31 surrounding the main bar 30 inside. The main bar 30 is connected to the main bar 30 extending from the lower floor by using a mechanical joint 32. Further, the upper end of the main bar 30 extends further upward from the area where the slab 4 on the upper floor is constructed over the length required for connecting the main bar 30 on the upper floor. The PCa wall 10 and the pillar 2 further have a plurality of aggregated horizontal bars 33 arranged substantially horizontally on the upper side and the lower side of the inside thereof. The aggregation horizontal bars 33 are arranged at predetermined intervals in the vertical direction. The integrated horizontal streaks 33 of the PCa wall 10 extend in the horizontal direction from the left and right end faces of the PCa wall 10. The integrated horizontal bars 33 of the PCa wall 10 are arranged in the area where the cast-in-place wall 11 is constructed, and extend to the vicinity of the pillar 2 adjacent to the PCa wall 10 or the PCa wall 10. The centralized horizontal streaks 33 of the pillar 2 are embedded in the pillar 2 over a predetermined length and extend horizontally toward the PCa wall 10. The integrated horizontal bars 33 of the columns 2 are arranged in the area where the cast-in-place wall 11 is constructed, and extend to the vicinity of the adjacent PCa wall 10. The length of the cast-in-place wall 11 in the left-right direction may be such that the integrated horizontal bars 33 extending from the PCa wall 10 and the pillar 2 or the PCa wall 10 facing each other can secure the joint length of the lap joint. ..

The cast-in-place wall 11 further has a plurality of integrated vertical bars 34 arranged substantially vertically, respectively. The aggregated vertical bars 34 are arranged at positions having predetermined intervals in the left-right direction and the front-back direction. When the in-situ striking wall 11 is also present on the upper floor, the integrated vertical bar 34 is constructed with the on-site striking wall 11 on the upper floor having a length required for the joint with the consolidating vertical bar 34 on the upper floor. Is extended to the area. In the present embodiment, the joint of the integrated vertical bar 34 is a lap joint. The joint of the integrated vertical bar 34 may be a mechanical joint, a welded joint, or a pressure welding joint.

The reinforcing bar 17 will be described with reference to FIG. 7. The reinforcing bar 17 includes the reinforcing bar of the half PCa version 16 and the reinforcing bar arranged at the site. The half PCa plate 16 has a reinforcing bar (not shown) that serves as a lower end bar of the slab 4 inside the PCa plate, and a truss bar 35 on the PCa plate. The reinforcing bar 17 is arranged by arranging the half PCa plate 16 at a predetermined position and additionally arranging the upper end reinforcing bar 36 and other necessary predetermined reinforcing bars. Beam position tensile bars 37 are arranged between the front and rear half PCa plates 16 and between the upper and lower walls 5. As a result, the concrete between the upper and lower walls 5 functions as the upper part of the beam 3.

Next, a method of constructing the building 1 will be described with reference to FIGS. 8 to 13. In the following, on the middle floor of the multi-story building 1, the PCa wall 10 on the lower floor is built, the main bar 30, the aggregate horizontal bar 33 and the aggregate vertical bar 34 on the lower floor are arranged, and the in-situ wall 11 on the lower floor is constructed. The procedure from the assembled state of the wall formwork 40 for construction and the pillar formwork 41 for constructing the pillar 2 to the construction of the slab 4 and the wall 5 on the target floor will be described.

In this method, first, the PCa wall 10 having the above-described configuration is manufactured as a factory secondary product. After that, the PCa wall 10 is transported to the construction site. Further, a half PCa plate 16 having the above-described configuration is manufactured as a factory secondary product. After that, the half PCa plate 16 is transported to the construction site.

Next, as shown in FIG. 8, the reinforcing bar 17 is arranged in the region where the slab 4 is constructed. The reinforcing bars 17 are arranged by arranging the half PCa plate 16 below the area where the slab 4 is constructed, and then additionally arranging other necessary predetermined reinforcing bars including the upper end reinforcing bars 36 and the beam reinforcing bars. A spacer 18 for placing the PCa wall 10 is arranged at a position avoiding the reinforcing bar 17 in the region where the slab 4 is constructed. The height of the spacer 18 is set to a height at which the lower end of the PCa wall 10 placed on the spacer 18 is buried in the area where the slab 4 is constructed. Alternatively, when a height-adjustable spacer 18 is used, the height of the spacer 18 is adjusted to the height described above. At the lower part of the area where the cast-in-place wall 11 is constructed, an integrated vertical bar 34 extending from the construction area of the cast-in-place wall 11 on the lower floor is arranged. Further, in the lower part of the area where the pillar 2 is constructed, a main bar 30 extending from the construction area of the pillar 2 on the lower floor is arranged. The half PCa plate 16 is used as a formwork for the concrete 15. Therefore, by arranging the half PCa plate 16, the formwork of the slab 4 is also arranged at the same time as the arrangement of the reinforcing bars 17. At this time, the formwork of the slab 4 is required, and the work of arranging an additional slab formwork (not shown) may be performed in a range where the half PCa plate 16 is not arranged.

Next, as shown in FIG. 9, the PCa wall 10 is arranged on the spacer 18. After that, the PCa wall 10 is fixed around the PCa wall 10 by using an appropriate fall prevention means so as not to fall. As a result, the PCa wall 10 is built in a predetermined position on the reinforcing bar 17 arranged. The integrated horizontal bars 33 extending from the left and right end faces of the PCa wall 10 are used as the horizontal bars of the in-situ wall 11. After the PCa wall 10 is built on the reinforcing bar 17, it is possible to arrange the reinforcing bar 17 on the next higher floor.

Next, as shown in FIG. 10, the reinforcing bars used for the column 2 and the in-situ wall 11 are arranged. The reinforcing bars of the columns 2 are arranged by connecting the main bars 30 of the target floor to the main bars 30 extending from the lower floor using a mechanical joint 32 and attaching the hoop bars 31 around the main bars 30. The upper end of the main bar 30 extends further upward from the area where the upper floor slab 4 is constructed over the length required to connect the upper floor main bar 30. Further, an integrated horizontal bar 33 is attached to the main bar 30 of the column 2. After that, the integrated vertical streaks 34 of the on-site striking wall 11 are arranged. The aggregated vertical bars 34 extend from the area on which the upper floor slab 4 is constructed over the length required to establish the aggregated vertical bars 34 on the upper floor.

Next, as shown in FIG. 11, concrete is placed inside the wall formwork 40 and the pillar formwork 41 on the lower floor and in the area where the slab 4 on the target floor is constructed. Then, after the concrete is cured for a predetermined period, the lower wall formwork 40 and the pillar formwork 41 are demolded. As a result, the on-site wall 11 on the lower floor, the pillar 2, and the slab 4 on the target floor are constructed. Since the lower end of the PCa wall 10 is arranged in the area where the slab 4 is constructed as described above, when the concrete 15 is placed in the area where the slab 4 is constructed, the lower end of the PCa wall 10 is buried in the slab 4. As a result, the inside of the plurality of shear cotters 14 recessed in the bottom of the PCa wall 10 is filled with the concrete 15. Further, when the concrete 15 is placed in the slab 4, vibration is applied to the inside of the shear cotter 14 by using a vibrator that vibrates the concrete 15. As a result, the air remaining in the shear cotter 14 can be discharged.

Next, as shown in FIG. 12, the wall formwork 40 for constructing the cast-in-place wall 11 is assembled. At this time, the pillar formwork 41 for constructing the pillar 2 is also assembled, and the wall formwork 40 and the pillar formwork 41 are integrally assembled. The wall formwork 40 is assembled from the upper surface of the slab 4 to the bottom surface of the area for constructing the slab 4 on the upper floor after the cast concrete 15 is hardened. Further, as the formwork for the slab 4 on the upper floor, the half PCa plate 16 on the upper floor is arranged on the PCa wall 10 and the wall formwork 40. After that, the upper floor reinforcing bar 17 is arranged by additionally arranging the upper end reinforcing bar 36 and other necessary predetermined reinforcing bars. At this time, the spacer 18 on the upper floor is also arranged. The half PCa plate 16 is not arranged in the front-rear direction of the pillar 2. Therefore, an additional formwork is required to construct the slab 4 extending in the front-rear direction of the pillar 2. As a work of arranging the additional slab 4 formwork, a wooden panel formwork is arranged in the front-rear direction of the pillar 2 so that the upper surface thereof and the lower surface of the half PCa plate 16 are continuous, and by support work (not shown). Be supported.

In the present embodiment, next, as shown in FIG. 13, the half PCa plate 16 is arranged on the wall formwork 40, and the PCa wall 10 on the upper floor is built on the half PCa plate 16. Next, the reinforcing bars used for the pillar 2 on the upper floor and the in-situ wall 11 are arranged. As a result, when concrete is placed inside the wall formwork 40 and the pillar formwork 41, the work of placing concrete in the area where the slab 4 on the upper floor is to be constructed can be performed at the same time.

Next, as shown in FIG. 14, concrete is placed inside the wall formwork 40 and the pillar formwork 41 on the target floor and in the area where the slab 4 on the upper floor is constructed. Then, after the concrete is cured for a predetermined period, the lower wall formwork 40 and the pillar formwork 41 are demolded. As a result, the on-site wall 11, the pillar 2, and the slab 4 on the upper floor are constructed on the target floor.

In another embodiment, the half PCa plate 16 on the upper floor is not arranged, and concrete is formed inside the wall formwork 40 and the pillar formwork 41 in a state where the PCa wall 10 on the upper floor is not built. After being placed, the concrete 15 on the upper floor is placed. In other words, the concrete of the cast-in-place wall 11 and the pillar 2 on the target floor and the concrete of the slab 4 on the upper floor are separated. At this time, the concrete in the pillar formwork 41 is cast to the same height as the upper surface of the wall formwork 40. As a result, the PCa wall 10 is connected to the adjacent pillars 2 and the PCa wall 10 by the cast-in-place wall 11, and the wall 5 is constructed between the pair of pillars 2. After that, the upper half PCa plate 16 is arranged on the upper surface of the wall 5, and the PCa wall 10 is built. As a result, the PCa wall 10 on the upper floor can be built into the wall 5 and the half PCa plate 16 arranged on the wall 5. Therefore, the fall prevention means of the PCa wall 10 can be simplified.

Next, the effect of the building 1 according to the present embodiment will be described. As shown in FIGS. 2, 3 and 6, the inside of the plurality of shear cotters 14 is filled with concrete 15. Further, the shear cotter 14 is open toward one surface of the PCa wall 10. As a result, the air in the shear cotter 14 can be discharged from the open portion of the shear cotter 14. Therefore, for example, by applying vibration inside the shear cotter 14 using a vibrator used when placing concrete 15, the air inside the shear cotter 14 can be discharged to the outside of the shear cotter 14. Therefore, by placing the concrete 15, the air in the shear cotter 14 recessed in the bottom of the PCa wall 10 is discharged without requiring another work, and the wall 5 and the beam 3 are discharged through the shear cotter 14. Can be joined with.

As shown in FIGS. 2, 4 and 5, the shear cotter 14 opened toward the first surface 12 of the wall 5 and the shear cotter 14 opened toward the second surface 13 of the wall 5 are alternately arranged. Has been done. As a result, the shearing force acting on the first surface 12 side and the shearing force acting on the second surface 13 side of the wall 5, that is, the shearing force in the in-plane direction becomes substantially equal. Further, the shearing force from the first surface 12 side to the second surface 13 side and the shearing force from the second surface 13 side to the first surface 12 side, that is, the shearing force in the out-of-plane direction are also substantially equal. For example, when only the shear cotter 14 opened toward the first surface 12 of the wall 5 is arranged, the shear force in the in-plane direction between the PCa wall 10 and the slab 4 or the beam 3 is the first of the wall 5. The transmission is biased toward the 12 side of one surface. Further, the shearing force from the first surface 12 side to the second surface 13 side is not transmitted from the wall 5 to the slab 4 and the beam 3, and the shearing force from the second surface 13 side to the first surface 12 side is transmitted to the slab. Since it is not transmitted from 4 or the beam 3 to the wall 5, the shear force in the out-of-plane direction is also transmitted unevenly. Therefore, as compared with this case, the shearing force generated between the PCa wall 10 and the slab 4 or the beam 3 can be efficiently transmitted to the shear cotter 14.

As shown in FIG. 3, the upper surface of the shear cotter 14 has a slope that increases toward the surface of the PCa wall 10 on the side where the shear cotter 14 is opened. As a result, when the surface of the concrete cast in the area where the slab 4 is constructed in the shear cotter 14 approaches the upper surface of the shear cotter 14, the concrete surface then rises along an outward gradient. Therefore, the air in the shear cotter 14 is pushed out by the concrete and taken by the concrete. Therefore, it is possible to make it difficult for an air pool to be generated in the shear cotter 14. Therefore, the concrete 15 and the shear cotter 14 can effectively transmit the shearing force between the slab 4 and the wall 5 with respect to each other.

As shown in FIG. 4, the area of the shear cotter 14 on the bottom surface of the PCa wall 10 is about 40 to 60% of the area of the bottom surface of the PCa wall 10. As a result, on the bottom surface of the PCa wall 10, a shear key having a size of about 40 to 60% of the area is constructed. Therefore, it is possible to construct a shear connector in which the ratio of the shear key to the concrete of the PCa wall 10 is approximately 1: 1. Therefore, shear failure of shear key and PCa concrete generated by the shearing force in the in-plane direction is less likely to occur. Therefore, it is possible to construct a shear connector that is not easily destroyed.

As shown in FIGS. 4A and 4B, the shear cotter 14 has a tapered shape that extends toward the surface on which it is opened. As a result, the shear cotter 14 can visually check the entire inside from the outside. Therefore, when the wall 5 is viewed from the front, the inside of the shear cotter 14 can be easily seen to the back. Further, between the time when the inside of the shear cotter 14 is filled with the concrete 15 and the time when the concrete 15 is hardened, vibration is generated in the shear cotter 14 by using an instrument such as a vibrator, and it is visually confirmed that no air bubbles are generated. Therefore, it is possible to visually confirm that there is no air pool in the shear cotter 14. In the present embodiment, since the upper surface of the shear cotter 14 is substantially the same as the upper surface of the slab 4, the inside of the shear cotter 14 can be visually confirmed until immediately before the completion of the placement of the concrete 15. Therefore, it is possible to visually confirm whether or not the inside of the shear cotter 14 is completely filled with the concrete 15. Further, since the shear cotter 14 spreads outward, it is difficult for the air discharge portion to be blocked when filling the inside of the shear cotter 14. Therefore, the air in the shear cotter 14 is easily taken in, and the air pool in the shear cotter 14 is less likely to be generated. Therefore, the workability of the work of joining the wall 5 and the beam 3 can be improved.

As shown in FIGS. 5 (B), (D) and (E), two shear cotters 14 adjacent to each other are connected by a connecting groove 20. As a result, for example, when concrete 15 is cast from the first surface 12 side, the air in the shear cotter 14 opened to the first surface 12 side is connected to the shear cotter 14 on the second surface 13 side connected by the connecting groove 20. Will be taken. As a result, air pools in the shear cotter 14 are less likely to occur. Further, as shown in FIGS. 5A and 5C, a connecting groove 20 for connecting the shear cotter 14 and the end surface of the PCa wall 10 is further provided. As a result, the number of places where air can be discharged in the shear cotter 14 is further increased, and it becomes more difficult for air pools to be generated in the shear cotter 14.

Next, the effect of the method for constructing the building 1 according to the present embodiment will be described. As shown in FIG. 11, the concrete 15 is filled inside the shear cotter 14 by placing the concrete 15. Further, the air pool in the shear cotter 14 can be discharged from the shear cotter 14 by the vibrator used when placing the concrete 15. Therefore, other work for filling the inside of the shear cotter 14, for example, burying the shear cotter 14 with mortar or grout, or attaching an air bleeding hose for discharging the air in the shear cotter 14 is unnecessary. It becomes. Therefore, by placing the concrete 15, the air in the shear cotter 14 recessed in the bottom of the PCa wall 10 is discharged without requiring another work, and the wall 5 and the beam 3 are discharged through the shear cotter 14. Can be joined with.

As shown in FIGS. 6, 10 and 12, the wall 5 includes the PCa wall 10 and the cast-in-place wall 11, and a pair of PCa walls 10 adjacent to each other are connected to each other via the cast-in-place wall 11. There is. As a result, the wall 5 can be further extended in the in-plane direction by adding a cast-in-place portion to the PCa wall 10 as needed. Therefore, a long wall 5 can be constructed in the in-plane direction. Further, the PCa wall 10 is connected to the pillar 2 and the slab 4 via the cast-in-place wall 11. Therefore, the wall 5 can be constructed inside the frame surface that is long in the in-plane direction. At the construction site, the work of arranging the reinforcing bars and the work of assembling the formwork are not performed on the portion of the wall 5 where the PCa wall 10 is arranged. As a result, less work is performed at the construction site than in the case of constructing a wall 5 that does not include the PCa wall 10 having the same area. Therefore, by using at least one PCa wall 10 for the frame surface long in the in-plane direction, a part of the work of arranging the reinforcing bars for constructing the wall 5 inside the frame surface and the work of assembling the formwork. Can be omitted, and the construction period for constructing the building 1 can be shortened.

As shown in FIG. 8, by arranging the half PCa plate 16, most of the reinforcing bars 17 are arranged, and most of the formwork of the slab 4 is assembled. This simplifies the work of arranging the reinforcing bars 17 and the work of assembling the formwork of the slab 4. Therefore, the construction period for constructing the concrete building 1 can be shortened.

<< Second Embodiment >>
Next, the building 51 according to the second embodiment is different from the first embodiment in that the pillar 52 in the building 51 is composed of the PCa concrete pillar 52 (hereinafter, PCa pillar 52), and the other configurations are different. The same is true. Therefore, the description of other configurations is omitted, and the same reference numerals are given.

FIG. 15 is a cross-sectional view in the beam-to-beam direction of the building 51 whose construction has been completed. Further, in FIG. 15, the arrangement of the reinforcing bars of the wall 5, the PCa column 52, and the slab 4 is transparently shown. As shown in FIG. 15, the PCa column 52 has a large-diameter main bar 30 inside, a thin hoop bar 31 surrounding the main bar 30, and an integrated horizontal bar arranged substantially horizontally on the upper side and the lower side. It is a factory secondary product having 33. A sleeve joint 53 (mechanical joint) that opens toward the bottom surface is provided at the lower end of the PCa column 52. The main bar 30 of the PCa column 52 is arranged in the PCa column 52 so that the lower end portion thereof extends into the sleeve joint 53 and the upper end portion thereof extends from the upper surface of the PCa column 52.

The PCa pillar 52 is placed on the intermediate floor by being placed on the PCa pillar 52 on the lower floor. At this time, the PCa pillar 52 on the intermediate floor is arranged so that the sleeve joint 53 of the PCa pillar 52 on the intermediate floor receives the main bar 30 extending to the upper surface of the PCa pillar 52 on the lower floor. The sleeve joint 53 has a grout injection port (not shown) leading from the surface of the PCa column 52 to the lower part of the sleeve joint 53, and an air vent port (not shown) leading from the upper part of the sleeve joint 53 to the surface of the PCa column 52. It is provided. The sleeve joint 53 is filled inside by injecting grout from the grout injection port, whereby the main bar 30 on the lower floor and the main bar 30 on the middle floor are connected.

Next, the effect of the building 51 according to the second embodiment will be described. Since the pillar 52 of the building 51 of the second embodiment is the PCa pillar 52, the PCa pillar 52 can be assembled before the cast-in-place wall 11 is constructed (before the work of FIG. 9 in the first embodiment). it can. As a result, when the PCa wall 10 is built, it is possible to provide a fall prevention means for the PCa wall 10 using the PCa pillar 52. Therefore, the fall prevention means can be further simplified. The work of assembling the PCa column 52 may be performed before or after the reinforcing bar 17 is arranged (the work of FIG. 8 in the first embodiment).

Although the description of the specific embodiment is completed above, the present invention can be widely modified without being limited to the above embodiment. In the above aspect, the buildings 1 and 51 are reinforced concrete plate-shaped multi-story buildings, but the present invention is not limited to this aspect. Buildings 1 and 51 may be a steel-framed reinforced concrete structure, or a composite structure or a mixed structure of a reinforced concrete structure and a steel frame. Further, the buildings 1 and 51 may be a flying geese type or a single-story building.

In the above aspect, the wall 5 connects a pair of columns 2 arranged in the beam-to-beam direction of the buildings 1 and 51, but the present invention is not limited to this aspect. The wall 5 may connect a pair of columns 2 arranged in the girder direction of the buildings 1 and 51. Further, although the wall 5 constitutes a multi-story earthquake-resistant wall, it may be a single-layer earthquake-resistant wall or a non-bearing wall.

In the above aspect, the beam 3 of the buildings 1 and 51 is a wall beam, but the present invention is not limited to this aspect. As shown in FIG. 16, the beam 3 may be a beam having a width wider than the wall thickness. Further, the beam 3 may be a half PCa beam including a half PCa beam portion integrally formed with the PCa wall 10 on the upper portion of the PCa wall 10 and a cast-in-place beam portion, and does not include the half PCa beam portion. It may be a cast-in-place beam constructed only by cast-in-place concrete.

In the above aspect, the PCa wall 10 is joined to the beam 3, but the present invention is not limited to this aspect. The PCa wall 10 may be joined to the slab 4 (in other words, the portion of the wall 5 where the PCa wall 10 and the beam 3 are joined at the height position of the slab 4) as shown in FIG. In this case, the beam 3 is integrally formed on the upper part of the PCa wall 10, and the slab 4 is constructed on the beam 3. The beam 3 may be formed separately from the PCa wall 10 and may be joined by an appropriate joining method.

The PCa wall 10 and the PCa pillar 52 may be prestressed. In this case, a sheath pipe is embedded in the PCa wall 10 and the PCa pillar 52, and a tense PC steel wire is arranged in the sheath pipe.

The concrete cast at the construction site may contain a defoaming material. In this case, air pools in the shear cotter 14 are less likely to occur.

1: Building 3: Beam 4: Slab 5: Wall 10: PCa concrete wall (PCa wall)
11: In-situ wall 12: 1st surface 13: 2nd surface 14: Sheacotter 15: Concrete 16: Half PCa version 17: Reinforcing bar 20: Connecting groove 33: Consolidating horizontal bar 34: Consolidating vertical bar 35: Truss bar 36: Top bar 37: Beam position tensile bar 40: Wall formwork 51: Building

Claims (8)

A concrete building having a slab or a beam and a wall having a first surface and a second surface parallel to the main surface and rising from the slab or the beam.
The wall comprises a PCa concrete wall at least in part, and the PCa concrete wall has a plurality of shear cotters recessed at the bottom.
Each of the plurality of shear cotters is open to only one of the first surface and the second surface, and the plurality of shear cotters are placed on the first surface side and the second surface side in the length direction of the wall. Alternately arranged,
A concrete building characterized in that the lower end of the PCa concrete wall is embedded in the slab or the beam. The concrete building according to claim 1, wherein the upper surface of the shear cotter has a slope that increases toward the first surface or the second surface to which the shear cotter is opened. The concrete building according to claim 1 or 2, wherein the area of the shear cotter on the bottom surface of the PCa concrete wall is 40 to 60% of the area of the bottom surface. The concrete structure according to any one of claims 1 to 3, wherein the shear cotter has a tapered shape extending toward the first surface or the second surface on which the shear cotter is opened. Building. The concrete building according to any one of claims 1 to 4, wherein the PCa concrete wall further has a connecting groove for connecting the two shear cotters adjacent to each other. A method for constructing a concrete building having a slab or a beam and a wall having a first surface and a second surface parallel to the main surface and rising from the slab or the beam.
A PCa concrete wall that is open to only one of the first surface and the second surface and has a plurality of shear cotters arranged alternately on the first surface side and the second surface side in the length direction of the wall at the bottom. And the steps to manufacture
The step of arranging the reinforcing bar in the area where the slab or the beam should be constructed, and
The step of building the PCa concrete wall at a predetermined position on the rebar arranged, and
A method for constructing a concrete building, which comprises a step of placing concrete in an area for constructing the slab or the beam so that the lower end of the PCa concrete wall is embedded in the slab or the beam. .. The wall further includes a cast-in-place portion constructed of cast-in-place concrete.
After the step of building the PCa concrete wall, a step of arranging the wall reinforcement used for the cast-in-place portion around the PCa concrete wall, and
After the step of placing concrete on the slab or the beam, the step of assembling the wall formwork for constructing the cast-in-place portion, and
The method for constructing a concrete building according to claim 6, further comprising a step of placing concrete inside the wall formwork. The construction of a concrete building according to claim 6 or 7, wherein the step of arranging the reinforcing bars includes arranging a half PCa plate under the region for constructing the slab or the beam. Method.

Images