JP7231523B2 - Concrete building and its construction method - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to concrete buildings and construction methods thereof, and more particularly to concrete buildings having slabs or beams and walls rising from the slabs or beams and construction methods thereof.

Buildings with earthquake-resistant structures constructed using precast concrete walls are known (for example, Patent Document 1). This building has a beam-column structure made of concrete columns and beams, and a precast concrete seismic wall placed in the beam-column structure. Concave portions (shea cotter) are formed horizontally at regular intervals on the side surfaces of the pillars and the upper and lower end surfaces of the beams. Similarly, recesses are formed on the side surfaces and upper and lower end surfaces of the earthquake-resistant wall. The seismic wall is placed in the column-beam frame with a gap from the columns and beams so that the recesses of the walls face the recesses of the columns and beams. It is fixed to the beam frame. The concave portion of the earthquake-resistant wall, the concave portion of the column beam, and the grout material filled in these concave portions function as shear connectors that transmit shear force between the column beam and the earthquake-resistant wall.

Other structural buildings constructed with precast concrete walls are also known (eg US Pat. The building has a post-beam frame of PCa concrete columns and PCa concrete beams and a plurality of PCa concrete wall panels joined in-plane. A PCa concrete wall panel is provided with intensive horizontal reinforcement and intensive vertical reinforcement as intensive reinforcing bars arranged around its perimeter. The intensive transverse bars are arranged substantially horizontally on the upper and lower sides inside the PCa concrete wall panel and protrude outward from the left and right end faces of the PCa concrete wall panel. Concentrated longitudinal bars are generally vertically positioned on the left and right exterior sides of the PCa concrete wall panel and have extensions that can be anchored to the PCa concrete beams. From the PCa concrete pillars project transverse bars corresponding to the transverse bars of the PCa concrete wall panels. In a space surrounded by PCa concrete columns, PCa concrete wall panels, and PCa concrete beams, cast-in-place concrete is placed after intensive reinforcing bars are arranged. This joins the column beam and the PCa concrete wall panel. PCa concrete wall panels are also installed directly on PCa concrete beams. Alternatively, the PCa concrete wall panels are affixed to the PCa concrete beams using mortar, grout, or the like. In this case, the surfaces of the PCa concrete wall panels and PCa concrete beams that come into contact with the laying mortar and grout become rough.

JP 2017-206844 JP 2009-293347

When constructing the seismic wall structure described in Patent Document 1 with cast-in-place concrete, the filling of the cotter with the grout material is carried out separately from the pouring of the concrete into the beams. Therefore, a separate work from pouring concrete is required to fill the cotter. Also, when filling the grout material into the cotter provided on the lower surface of the precast concrete wall, attach an air release hose to the precast concrete wall to draw the air inside the cotter to the outside, and check that the air is being drawn in. It is necessary to confirm. Therefore, the manufacturing of the precast concrete wall and the work of filling the grout into the cotter are complicated. Furthermore, even with an air bleeder hose, it is difficult to ensure that all areas within the cotter are free of air pockets.

Patent Literature 2 describes roughening the bottom of a PCa concrete wall panel so that it adheres to laying mortar, grout, or the like. In this work, other work such as mortar laying work and grout pouring work is required.

SUMMARY OF THE INVENTION In view of the above background, the present invention provides a concrete building that includes PCa concrete walls by pouring the concrete that builds the slabs or beams, without the need for a separate operation. An object of the present invention is to discharge the air in a shea cotter recessed in the bottom and join a wall and a slab or a beam through the shea cotter.

To solve such problems, an embodiment of the invention comprises a slab (4) or beam (3) and a first surface (12) and a second surface (13) parallel to the main surface. A concrete building (1, 51) comprising a wall (5) rising from said slab or said beam, said wall at least partially including a PCa concrete wall (10), said PCa concrete wall at the bottom a plurality of shea cotta (14) recessed therein, each of said plurality of shea cottas (14) being open to only one of said first surface and said second surface, and a plurality of said shea cottas extending the length of said wall; The PCa concrete walls are alternately arranged on the first surface side and the second surface side in the direction, and the lower ends of the PCa concrete walls are embedded in the slabs or the beams.

According to this configuration, since a plurality of shea cotta is open only on one of the first and second sides of the wall, concrete is poured to build a slab or beam so that the lower end of the PCa concrete wall is buried. Then, the air in the shea cotta is discharged to the outside from the open end face, and the shea cotta is filled with concrete. Therefore, by placing concrete, the air in the shea cotta recessed in the bottom of the PCa concrete wall is discharged without requiring a separate work, and the wall and the slab or beam are joined through the shea cotta. can do. In addition, a plurality of shea cottas that are open only on one of the first and second surfaces of the wall are alternately arranged. This allows the in-plane direction (longitudinal direction of the PCa concrete wall) and Shear forces in the out-of-plane direction (the width direction of the PCa concrete wall) are generally evenly transmitted. Therefore, the shear force in the in-plane direction can be efficiently transmitted to the shea cotta.

In the above configuration, the upper surface of the shea cotta preferably has a slope that increases toward the first surface or the second surface where the shea cotta is open.

According to this configuration, when the shea cotta is filled with concrete, the concrete in the shea cotta rises along the gradient of the upper surface of the shea cotta, so the air in the shea cotta is carried outside by the concrete. Therefore, it is possible to make it difficult for air pockets to occur in the shea cotta. Concrete and sheacotta therefore allow the effective transfer of shear forces between the slab and wall relative to each other.

In the above structure, the area of the shea cotta 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, on the bottom surface of the PCa concrete wall, the area ratio of the shea cotta and the PCa concrete is approximately 1:1. As a result, both the concrete in the shea cotta and the shear failure of the lower end of the PCa concrete wall are less likely to occur. Therefore, the shear failure of the shear connector is less likely to occur.

In the above configuration, the shea cotta preferably has a tapered shape that widens toward the first surface or the second surface where the shea cotta is open.

According to this configuration, when the wall is viewed from the front, the inside of the shea cotta can be easily seen to the depth. Thereby, it is possible to visually confirm whether or not the inside of the shea cotta is filled with concrete. In addition, since the open end face of the shea cotta is widened, the air in the shea cotta is easily entrained. Therefore, it becomes easier to confirm that the air in the shea cotta has been removed. Therefore, the workability of joining the wall and the slab or beam is improved.

In the above configuration, the PCa concrete wall may further have a connecting groove (20) connecting two adjacent shea cotta pieces.

According to this configuration, when one of the two shea cotta adjacent to each other is filled with concrete, the air in the shea cotta is entrained to the other shea cotta. This makes it even more difficult for air to be trapped inside the shea cotta.

In order to solve such problems, another embodiment of the present invention has a slab (4) or beam (3) and a first surface (12) and a second surface (13) parallel to the main surface. and a wall (5) rising from the slab or the beam, wherein only one of the first surface and the second surface is opened, and the wall manufacturing a PCa concrete wall (10) having a plurality of shea cotta (14) at the bottom, alternately arranged longitudinally on said first face side and said second face side; and constructing said slab or said beam. Placing rebar (17, 35, 36, 37) in the area to be rebar (Fig. 8) and erecting said PCa concrete wall in place on said rebar placed (Fig. 9); pouring concrete (15) in the area where the slab or beam will be built so that the lower edge of the PCa concrete wall is embedded in the slab or beam (Fig. 11).

According to this configuration, since the plurality of shea cotta provided at the bottom of the PCa concrete wall is open only to one of the first and second surfaces of the wall, the inside of the shea cotta is vibrated by a vibrator used when placing concrete. of air can be discharged from inside the shea cotta. The shea cotta is thereby filled with concrete by pouring concrete in the areas where the slabs or beams will be built. Therefore, other work such as burying the shea cotta recessed in the bottom of the PCa concrete wall with mortar or grout, or attaching an air release hose becomes unnecessary. Thus, by pouring the concrete that builds the slabs or beams, joining the walls and slabs or beams through the shea cotta recessed into the bottom of the PCa concrete wall without a separate operation. can be done.

In the above arrangement, further comprising a cast-in-place part (11) wherein said wall is constructed by cast-in-place concrete, the method comprising, after the step of erecting said PCa concrete wall (Fig. 9): for building the cast-in-place part after placing the wall reinforcement (33, 34) for the cast-in-place part (Fig. 10) and pouring the concrete in the slab or the beam (Fig. 11) 12) and pouring concrete into said wall form (FIG. 14).

With 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 to extend the wall as needed. This allows the addition of cast-in-place sections between the PCa concrete walls to build long walls in the in-plane direction. Therefore, by using at least one PCa concrete wall for the wall that is long in the in-plane direction, part of the work of arranging the wall reinforcement and assembling the formwork for building the wall can be omitted, and the concrete structure can be constructed. It is possible to shorten the construction period to construct a building.

In the above arrangement, the step of placing the rebar (Fig. 8) may include placing a half PCa slab (16) under the area where the slab or beam is to be built.

With this arrangement, the half PCa slabs can be used as replacements for at least some of the rebar and formwork for building the slabs or beams. This makes it possible to simplify the work of arranging reinforcing bars for slabs or beams and the work of assembling formwork for slabs or beams. Therefore, the construction period for constructing a concrete building can be shortened.

Thus, according to the present invention, in a concrete building including a PCa concrete wall, the shea cotta is recessed into the bottom of the PCa concrete wall by pouring concrete without requiring a separate operation. The air inside can be exhausted and the walls and slabs or beams can be joined via shea cotta.

Cross-sectional view of the building in the direction between beams, showing an intermediate floor in the building according to the first embodiment Front sectional view of the joint between the PCa concrete wall and the beam Cross-sectional view along line III-III in Fig. 2 (A) A bottom view of the PCa concrete wall showing the arrangement and shape of the shea cotta according to the first embodiment, and (B) to (E) Bottom views of the PCa concrete wall showing other arrangements and shapes of the shea cotta. (A)-(E) Bottom views of PCa concrete walls showing placement and shape of shea cotta connected by connecting grooves. Sectional view of the span direction of the building under construction Cross-sectional view along line VII-VII in Fig. 6 Explanatory drawing of building construction procedure according to the first embodiment Explanatory drawing of building construction procedure according to the first embodiment Explanatory drawing of building construction procedure according to the first embodiment Explanatory drawing of building construction procedure according to the first embodiment Explanatory drawing of building construction procedure according to the first embodiment Explanatory drawing of building construction procedure according to the first embodiment Explanatory drawing of building construction procedure according to the first embodiment Cross-sectional view in the direction between beams in the building according to the second embodiment Cross-sectional view of a joint between a PCa concrete wall and a beam according to another embodiment Sectional view of a joint between a PCa concrete wall and a slab according to another embodiment

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

As shown in FIG. 1, the building 1 according to the present embodiment is a plate-shaped multi-story building made of reinforced concrete. A building 1 includes a pair of pillars 2 arranged in a direction between beams, a plurality of beams 3 provided on each floor so as to connect the pair of pillars 2, and a plurality of beams 3 provided on each floor so as to be supported by the beams 3. and a plurality of walls 5 forming seismic walls constructed on the frame plane of each floor composed of a pair of pillars 2 and a pair of upper and lower beams 3. The beam 3 is formed at the upper end of the wall 5 with the same thickness as the wall 5 as a wall beam. A plurality of walls 5 are provided at the same position in a plan view, and constitute a multi-layer seismic wall. The slabs 4 are joined to the upper ends of the beams 3 of the corresponding floor and the walls 5 of each floor are built on the beams 3 and rise from the slabs 4 . The building 1 further has beams and walls in the girder direction, but illustration of these is omitted.

The column 2 in this embodiment is constructed with cast-in-place concrete. The wall 5 includes at least a portion of a PCa concrete wall 10 (hereinafter referred to as PCa wall 10), and the portions other than the PCa wall 10 are made of cast-in-place concrete. Hereinafter, a portion of the wall 5 that is constructed by placing concrete on site is referred to as a cast-in-place wall 11 . In this embodiment, the wall 5 is composed of five PCa walls 10 and six cast-in-place walls 11 . A PCa wall 10 is positioned between a pair of posts 2, spaced from the posts 2 and from each other. A cast-in-place wall 11 is constructed between a column 2 and a 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 plane of the paper 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-rear direction (out-of-plane direction) will be defined with reference to the first surface 12 of the wall 5 viewed from the front.

As shown in FIGS. 2 and 3, the PCa wall 10 has a plurality of shea cotta 14 recessed into its bottom. Each of the plurality of shea cottas 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 shea cotta 14 is filled with concrete 15 that is poured when constructing the slab 4 . The upper surface of the shea cotta 14 has a slope that increases toward the surface where the shea cotta 14 is opened. A plurality of shea 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 at its bottom. Above the PCa wall 10 and the half PCa plate 16 are reinforcing bars 17 (see FIGS. 6 and 7) of the slab 4 and the beams 3 and spacers 18 for placing the PCa walls 10 at positions avoiding the reinforcing bars 17. are placed. The PCa wall 10 is erected on the half PCa plate 16 via spacers 18 so that the uppermost position of the shea cotta 14 is below the upper surface of the slab 4 before concrete 15 is placed. In this embodiment, the uppermost position of the shea cotta 14 is below the upper surface of the slab 4 and substantially the same as the upper surface of the slab 4 . The PCa wall 10 has its lower end embedded in the slab 4 when the concrete 15 is placed. Therefore, when the concrete 15 is placed, the inside of the shea cotta 14 is filled with the concrete 15 . The concrete 15 filled in the shea cotter 14 serves as a shear key, and the sheer key and the concrete 15 at the lower end of the PCa wall 10 function as a shear connector that transmits shear force to each other.

The spacer 18 may be a block made of resin or a block made of metal. Alternatively, the spacer 18 may be a concrete projection 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 shea cottas 14 are arranged in the horizontal direction on the bottom of the PCa wall 10 and alternately arranged on the first surface 12 side and the second surface 13 side in the horizontal direction. ing. The plurality of shea cottas 14 provided on the first surface 12 side are arranged at intervals in the left-right direction, and the shea cotta 14 on the second surface 13 side is arranged in the center of the two adjacent shea cottas 14 in the left-right direction. ing. The planar shape of the shea cotta 14 at the bottom surface of the PCa wall 10 is preferably a tapered shape that widens from the inner side (wall core side of the PCa wall 10) toward the open surface. The planar shape of the shea cotta 14 according to this embodiment is a trapezoid that widens toward the end surface opened from the inside. A plurality of shea cotters 14 have the same shape and are formed so as to extend from the open end face to the wall core.

It should be noted that the shea cotta 14 may have other shapes. For example, as shown in FIG. 4B, the area of one shea cotta 14 can be reduced and the number of shea cotta 14 can be increased. Further, as shown in FIG. 4C, the planar shape of the shea cotter 14 may be a substantially circular shape with the center on the wall core side of the open end face. Further, as shown in FIG. 4D, the planar shape of the shea cotta 14 may be a semicircular shape that opens toward the open end surface. Further, as shown in FIG. 4E, the planar shape of the shea cotta 14 may be a substantially equilateral triangular shape with one side in contact with the open surface. The area of the shea cotta 14 is preferably 40-60% of the area at the bottom of the PCa wall 10 .

As shown in FIG. 5, in another embodiment of the present invention, the PCa wall 10 further has connecting grooves 20 connecting a plurality of shea cotta 14 at its bottom. The connecting groove 20 is provided so as to connect the closest points of the two shea cotta 14 adjacent to each other. The depth of the connecting groove 20 is equal to the depth of the shea cotta 14 (the height of the shea cotta 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 shea cotta 14 are connected to each other. . Further, the connecting groove 20 may be further provided at a position connecting the shea cotta 14 positioned on the end face side of the wall 5 and the end face of the wall 5 . The connection groove 20 is filled with the concrete 15 when the concrete 15 forming the upper portions of the slab 4 and the beam 3 is placed.

FIG. 6 is a cross-sectional view of the building 1 in the middle of construction in the direction of the span. Construction of the lower and intermediate floors has been completed, and the upper floor has been constructed. In addition, FIG. 6 transparently shows the arrangement of reinforcing bars of walls 5, columns 2 and slabs 4 in the constructed lower and intermediate floors. As noted above, walls 5 include PCa walls 10 and cast-in-place walls 11 . The area where the cast-in-place wall 11 is built is the top surface of the lower slab 4, the bottom surface of the area where the upper slab 4 is built, the side of the column 2 and the end surface of the opposing PCa wall 10, or the adjacent 2 and 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 plate 16 extends in the front-rear direction.

The PCa wall 10 has panel reinforcing bars (not shown) 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 reinforcement 30 inside and a small-diameter hoop reinforcement 31 surrounding the main reinforcement 30 . The main reinforcement 30 is connected to the main reinforcement 30 extending from the lower floor using a mechanical joint 32 . Also, the upper end of the main reinforcement 30 extends further upward from the area where the slab 4 of the upper floor is constructed over the length necessary to connect the main reinforcement 30 on the upper floor. The PCa wall 10 and the column 2 further have a plurality of intensive horizontal ribs 33 arranged substantially horizontally on their inner upper and lower sides, respectively. The intensive horizontal muscles 33 are arranged at predetermined intervals in the vertical direction. The intensive transverse ribs 33 of the PCa wall 10 extend horizontally from the left and right end faces of the PCa wall 10 . Aggregate transverse bars 33 of the PCa wall 10 are located in the area where the cast-in-place wall 11 is built and extend to the pillars 2 adjacent to the PCa wall 10 or to the vicinity of the PCa wall 10 . Aggregate transverse ribs 33 of the column 2 are embedded over a predetermined length inside the column 2 and extend horizontally toward the PCa wall 10 . Aggregate transverse bars 33 of the columns 2 are located in the areas where the cast-in-place walls 11 are built and extend to the vicinity of the adjacent PCa walls 10 . The length of the cast-in-place wall 11 in the left-right direction is sufficient as long as the aggregated horizontal reinforcements 33 extending from the PCa wall 10 and the column 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 intensive vertical bars 34 each arranged substantially vertically. The intensive vertical bars 34 are arranged at positions having predetermined intervals in the left-right direction and the front-rear direction. When the in-place concrete reinforcement 11 exists also on the upper floor, the in-place concrete reinforcement 34 on the upper floor is constructed with a length necessary for the joint with the in-place concrete reinforcement 34 of the concrete construction wall 11 on the upper floor. is extended to the area where In this embodiment, the joints of the intensive longitudinal bars 34 are lap joints. The joints of the intensive longitudinal reinforcements 34 may be mechanical joints, welded joints, or pressure joints.

The reinforcing bar 17 will be described with reference to FIG. The reinforcing bars 17 include the reinforcing bars of the half PCa version 16 and the reinforcing bars placed on site. The half PCa plate 16 has a reinforcing bar (not shown) serving as the bottom end reinforcement of the slab 4 inside the PCa plate, and a truss bar 35 on the PCa plate. The rebar 17 is placed by placing the half PCa plate 16 in place and additionally placing the top rebar 36 and any other required rebars in place. 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 beams 3.

Next, a method for constructing the building 1 will be described with reference to FIGS. 8 to 13. FIG. Below, in the middle floor of the multi-story building 1, the PCa wall 10 of the lower floor is erected, the main reinforcement 30 of the lower floor, the intensive horizontal reinforcement 33 and the intensive vertical reinforcement 34 are arranged, and the cast-in-place wall 11 of the lower floor is installed. A procedure from the state in which the wall formwork 40 for construction and the column formwork 41 for constructing the column 2 are assembled to the construction of the slab 4 and wall 5 of the target floor will be described.

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

Next, reinforcing bars 17 are placed in the area where the slab 4 is to be built, as shown in FIG. Reinforcing bars 17 are placed by placing the half PCa slabs 16 at the bottom of the area where the slab 4 is to be built, followed by the additional placement of the top bars 36 and any other required predetermined reinforcing bars, including beam bars. A spacer 18 is arranged for mounting the PCa wall 10 at a position avoiding the reinforcing bars 17 in the area where the slab 4 is built. The height of the spacer 18 is set so that the lower end of the PCa wall 10 placed on the spacer 18 is buried in the region where the slab 4 is constructed. Alternatively, if adjustable-height spacers 18 are used, the height of the spacers 18 is adjusted to the heights previously described. In the lower part of the area where the cast-in-place wall 11 is to be constructed, an intensive vertical reinforcement 34 extending from the construction area of the cast-in-place wall 11 on the lower floor is arranged. In addition, a main reinforcement 30 extending from the construction area of the column 2 on the lower floor is arranged in the lower part of the construction area of the pillar 2 . Half PCa plate 16 is used as a formwork for concrete 15 . Therefore, by arranging the half PCa plate 16, the formwork for the slab 4 is arranged at the same time as the reinforcing bars 17 are arranged. At this time, a formwork for the slab 4 is necessary, and an additional slab formwork (not shown) may be arranged in a range where the half PCa plate 16 is not arranged.

The PCa walls 10 are then placed on the spacers 18 as shown in FIG. The PCa wall 10 is then secured around its perimeter against tipping using suitable anti-tipping means. As a result, the PCa wall 10 is erected at a predetermined position on the rebars 17 arranged. Consolidated horizontal reinforcements 33 extending from the left and right end faces of the PCa wall 10 are used as horizontal reinforcements of the cast-in-place wall 11 . After the PCa wall 10 is erected on the rebar 17, it becomes possible to place the rebar 17 of the floor above.

Next, as shown in FIG. 10, the reinforcing bars used for the column 2 and the cast-in-place wall 11 are arranged. The reinforcing bars of the column 2 are arranged by connecting the main reinforcing bars 30 extending from the lower floor to the main reinforcing bars 30 of the target floor using mechanical joints 32 and attaching hoop reinforcing bars 31 around the main reinforcing bars 30 . The upper ends of the main bars 30 extend further up from the area where the upper story slabs 4 are built over the length required to connect the upper story main bars 30 . Furthermore, intensive horizontal reinforcements 33 are attached to the main reinforcements 30 of the columns 2 . After that, the central longitudinal reinforcement 34 of the cast-in-place wall 11 is placed. The central longitudinal bar 34 extends from the area of construction of the upper story slab 4 over the length required to anchor the upper story central bar 34 .

Next, as shown in FIG. 11, concrete is placed inside the wall formwork 40 and the column formwork 41 of the lower floor and in the area where the slab 4 of the target floor is to be constructed. Thereafter, after the concrete is cured for a predetermined period, the wall formwork 40 and the column formwork 41 of the lower floor are demoulded. As a result, the cast-in-place wall 11 of the lower floor, the column 2 and the slab 4 of the target floor are constructed. As described above, the lower end of the PCa wall 10 is located within the area where the slab 4 is to be constructed. As a result, the interiors of a plurality of shea cotta 14 recessed in the bottom portion of the PCa wall 10 are filled with concrete 15 . Further, when the concrete 15 is poured into the slab 4, the shea cotter 14 is vibrated by using a vibrator that vibrates the concrete 15. - 特許庁Thereby, the air remaining in the shea cotta 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 column formwork 41 for constructing the column 2 is also assembled, and the wall formwork 40 and the column formwork 41 are assembled integrally. The wall formwork 40 is assembled from the top surface of the slab 4 to the bottom surface of the area where the slab 4 of the upper floor will be built after the poured concrete 15 has hardened. Also, as a formwork for the slab 4 of the upper floor, the half PCa slab 16 of the upper floor is arranged on the PCa wall 10 and the wall formwork 40 . Thereafter, the upper floor rebar 17 is placed by additionally placing the top bar 36 and any other required rebar. At this time, the spacer 18 on the upper floor is also arranged. Note that 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 longitudinally of the column 2 . As a work to arrange the formwork for the additional slab 4, the wooden panel formwork is arranged in the front and back direction of the column 2 so that the upper surface and the lower surface of the half PCa plate 16 are continuous, and are supported by shoring (not shown). Supported.

In this embodiment, next, as shown in FIG. 13, the half PCa slab 16 is placed on the wall formwork 40, and the PCa wall 10 of the upper floor is erected thereon. Next, the reinforcing bars used for the pillars 2 and the cast-in-place walls 11 on the upper floor are arranged. As a result, when pouring concrete inside the wall formwork 40 and the column formwork 41, it is possible to simultaneously pour concrete in the area where the slab 4 of the upper floor is to be constructed.

Next, as shown in FIG. 14, concrete is placed inside the wall formwork 40 and the column formwork 41 of the target floor and in the area where the slab 4 of the upper floor will be constructed. Thereafter, after the concrete is cured for a predetermined period, the wall formwork 40 and the column formwork 41 of the lower floor are demoulded. As a result, the cast-in-place wall 11 of the target floor, the column 2 and the slab 4 of the upper floor are constructed.

In another embodiment, concrete is placed inside the wall formwork 40 and inside the column formwork 41 without the upper floor PCa slabs 16 being placed and the upper floor PCa walls 10 not being erected. After casting, the concrete 15 of the upper floor is cast. In other words, the concrete for the cast-in-place wall 11 and the column 2 on the target floor and the concrete for the slab 4 on the upper floor are separated. At this time, the concrete in the pillar formwork 41 is poured to the same height as the upper surface of the wall formwork 40 . This connects the PCa wall 10 to the adjacent pillar 2 and PCa wall 10 by the cast-in-place wall 11 and builds a wall 5 between a pair of pillars 2 . After that, the upper floor half PCa plate 16 is placed on the upper surface of the wall 5, and the PCa wall 10 is erected. This allows the PCa wall 10 of the upper floor to be erected against the wall 5 and the half PCa plate 16 placed thereon. Therefore, the overturn prevention means for the PCa wall 10 can be simplified.

Next, the effects of the building 1 according to this embodiment will be described. As shown in FIGS. 2, 3 and 6, the interiors of the plurality of shea cotta 14 are filled with concrete 15 . Also, the shea cotta 14 is opened toward one side of the PCa wall 10 . As a result, the air inside the shea cotta 14 can be discharged from the open portion of the shea cotta 14 . Therefore, the air in the shea cotter 14 can be discharged to the outside of the shea cotter 14 by vibrating the inside of the shea cotter 14 using a vibrator that is used when placing the concrete 15 , for example. Therefore, by placing the concrete 15, the air in the shea cotta 14 recessed in the bottom of the PCa wall 10 is discharged without requiring a separate work, and the wall 5 and the beam 3 are separated through the shea cotta 14. can be joined.

As shown in FIGS. 2, 4 and 5, the shea cotta 14 open toward the first surface 12 of the wall 5 and the shea cotta 14 open toward the second surface 13 of the wall 5 are alternately arranged. It is As a result, the shearing force acting on the first surface 12 side of the wall 5 and the shearing force acting on the second surface 13 side, that is, the shearing force in the in-plane direction, become substantially equal. In addition, the shear force directed from the first surface 12 side to the second surface 13 side and the shear force directed from the second surface 13 side to the first surface 12 side, that is, the shear force in the out-of-plane direction are substantially uniform. For example, when only the shea cotta 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 surface of the wall 5 . It is transmitted biased to the one surface 12 side. Further, the shearing force directed 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 beams 3, and the shearing force directed from the second surface 13 side to the first surface 12 side is transferred to the slab. Since the force is not transmitted from 4 or beam 3 to wall 5, the shear force in the out-of-plane direction is also transmitted unevenly. Therefore, the shear force generated between the PCa wall 10 and the slab 4 or beam 3 can be efficiently transmitted to the shea cotta 14 as compared with this case.

As shown in FIG. 3, the top surface of the shea cotter 14 has a slope that rises toward the surface of the PCa wall 10 on the side where the shea cotter 14 is open. As a result, when the surface of the concrete cast in the area where the slab 4 is to be constructed reaches the upper surface of the shea cotta 14, it then rises along the outward slope. Therefore, the air in the shea cotta 14 is pushed out by the concrete and entrained by the concrete. Therefore, it is possible to make it difficult for air pockets to occur in the shea cotta 14 . Therefore, the concrete 15 and the shea cotta 14 can effectively transmit the shear forces of the slab 4 and the wall 5 to each other.

As shown in FIG. 4, the area of the shea cotta 14 at the bottom of the PCa wall 10 is about 40-60% of the area of the bottom of the PCa wall 10 . This builds up a shear key at the bottom of the PCa wall 10 with a size of about 40-60% of its area. Therefore, a shear connector can be constructed in which the ratio of the shear key to the concrete of the PCa wall 10 is approximately 1:1. Therefore, shear failure of both shear key and PCa concrete caused by shear force in the in-plane direction is less likely to occur. Therefore, it is possible to construct a shear connector that is difficult to break.

As shown in FIGS. 4A and 4B, the shea cotta 14 has a tapered shape that widens toward the open surface. Thereby, the shea cotta 14 can be viewed from the outside to the entire inside. Therefore, when the wall 5 is viewed from the front, the inside of the shea cotta 14 can be easily seen to the depth. Also, during the period from when the concrete 15 is filled in the shea cotter 14 until the concrete 15 hardens, vibration is generated in the shea cotter 14 using a device 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 shea cotta 14 . In this embodiment, since the top surface of the shea cotter 14 is substantially the same as the top surface of the slab 4, the inside of the shea cotter 14 can be visually checked until immediately before the concrete 15 is placed. Therefore, it is possible to visually confirm whether or not the inside of the shea cotta 14 is completely filled with the concrete 15 . In addition, since the shea cotta 14 spreads outward, the air discharge portion is less likely to be blocked when the inside of the shea cotta 14 is filled. Therefore, the air inside the shea cotta 14 is more likely to be entrained, making it even more difficult for air to be trapped inside the shea cotta 14 . Therefore, the workability of joining the wall 5 and the beam 3 can be improved.

As shown in FIGS. 5(B), (D) and (E), two shea cottas 14 adjacent to each other are connected by a connecting groove 20 . As a result, for example, when concrete 15 is poured from the first surface 12 side, the air in the shea cotta 14 opened to the first surface 12 side flows to the shea cotta 14 on the second surface 13 side connected by the connecting groove 20. and will be accompanied. This makes it even more difficult for air to be trapped inside the shea cotta 14 . Further, as shown in FIGS. 5A and 5C, a connecting groove 20 connecting the shea cotta 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 from the shea cotter 14 is further increased, making it more difficult for air to be trapped inside the shea cotter 14 .

Next, the effects of the method for constructing the building 1 according to this embodiment will be described. As shown in FIG. 11 , concrete 15 is filled inside the shea cotta 14 by placing the concrete 15 . In addition, air trapped in the shea cotter 14 can be discharged from the shea cotter 14 by a vibrator used when placing the concrete 15 . Therefore, other work for filling the inside of the shea cotta 14, for example, work of burying the shea cotta 14 using mortar or grout, work of attaching an air release hose for discharging the air in the shea cotta 14, etc., is unnecessary. becomes. Therefore, by placing the concrete 15, the air in the shea cotta 14 recessed in the bottom of the PCa wall 10 is discharged without requiring a separate work, and the wall 5 and the beam 3 are separated through the shea cotta 14. can be joined.

As shown in FIGS. 6, 10 and 12, the wall 5 includes a PCa wall 10 and a cast-in-place wall 11, and a pair of adjacent PCa walls 10 are connected to each other via the cast-in-place wall 11. there is This allows cast-in-place portions to be added to the PCa wall 10 as needed to further extend the wall 5 in the in-plane direction. Therefore, a long wall 5 can be constructed in the in-plane direction. Furthermore, PCa wall 10 is connected to column 2 and slab 4 via cast-in-place wall 11 . Therefore, the wall 5 can be constructed inside the frame surface that is long in the in-plane direction. In the portion of the wall 5 where the PCa wall 10 is arranged, the work of placing reinforcing bars and the work of assembling the formwork are not performed at the construction site. This results in less work being done at the construction site compared to building a wall 5 that does not include a PCa wall 10 of the same area. Therefore, by using at least one PCa wall 10 for the frame surface that is long in the in-plane direction, 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 is omitted, and the construction period for constructing the building 1 can be shortened.

As shown in FIG. 8, most of the reinforcing bars 17 have been placed by placing the half PCa plate 16 and most of the formwork for the slab 4 has been assembled. This simplifies the work of arranging the reinforcing bars 17 and the work of assembling the formwork for 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 differs from the first embodiment in that the pillars 52 in the building 51 are PCa concrete pillars 52 (hereinafter referred to as PCa pillars 52). It is the same. Therefore, the description of other configurations is omitted, and the same reference numerals are assigned.

FIG. 15 is a cross-sectional view of the building 51 that has been completed in the span direction. In addition, FIG. 15 shows the arrangement of reinforcing bars of the wall 5, the PCa column 52 and the slab 4 in a transparent manner. As shown in FIG. 15, the PCa column 52 includes large-diameter main reinforcements 30, thin hoop reinforcements 31 surrounding the main reinforcements 30, and intensive horizontal reinforcements arranged substantially horizontally on the upper and lower sides. 33 is a factory secondary product. A sleeve joint 53 (mechanical joint) that opens toward the bottom is provided at the lower end of the PCa column 52 . The main reinforcement 30 of the PCa column 52 is arranged within the PCa column 52 such that its lower end extends into the sleeve joint 53 and its upper end extends from the upper surface of the PCa column 52 .

The PCa pillars 52 are placed on the PCa pillars 52 on the lower floor to be placed on the intermediate floor. At this time, the PCa column 52 of the intermediate floor is arranged so that the sleeve joint 53 of the PCa column 52 of the intermediate floor receives the main reinforcement 30 extending to the upper surface of the PCa column 52 of the lower floor. The sleeve joint 53 has a grout inlet (not shown) leading from the surface of the PCa pillar 52 to the lower part of the sleeve joint 53, and an air vent (not shown) leading from the upper part of the sleeve joint 53 to the surface of the PCa pillar 52. is provided. The interior of the sleeve joint 53 is filled by injecting grout from the grout injection port, thereby connecting the main reinforcement 30 of the lower floor and the main reinforcement 30 of the intermediate floor.

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

Although the specific embodiments have been described above, the present invention is not limited to the above embodiments and can be widely modified. In the above aspect, the buildings 1 and 51 are plate-shaped multi-layer buildings made of reinforced concrete, but are not limited to this aspect. The buildings 1 and 51 may be steel-framed reinforced concrete structures, composite structures of reinforced concrete structures and steel frames, or mixed structures. Also, the buildings 1 and 51 may be in the shape of a flying geese, or may be a single-story building.

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

In the above aspect, the beams 3 of the buildings 1 and 51 are wall beams, but are not limited to this aspect. The beam 3 may be a beam wider than the wall thickness as shown in FIG. Further, the beam 3 may be a half PCa beam including a half PCa beam part integrally formed with the PCa wall 10 on the upper part of the PCa wall 10 and a cast-in-place beam part, and does not include the half PCa beam part, It may be a cast-in-place beam that is constructed only from cast-in-place concrete.

In the above embodiment, the PCa walls 10 are joined to the beams 3, but are not limited to this embodiment. The PCa wall 10 may be joined to the slab 4 (in other words, the portion of the wall 5 that joins the PCa wall 10 and the beam 3 at the height of the slab 4) as shown in FIG. In this case, the beam 3 is integrally formed on top of the PCa wall 10, on which the slab 4 is built. The beam 3 may be formed separately from the PCa wall 10 and joined by an appropriate joining method.

The PCa walls 10 and PCa posts 52 may be prestressed. In this case, the PCa wall 10 and the PCa column 52 have a sheath tube embedded therein, and a tensioned PC steel wire is placed in the sheath tube.

The concrete placed at the construction site may contain an antifoaming agent. In this case, it becomes even more difficult for air to be trapped inside the shea cotta 14 .

1: Building 3: Beam 4: Slab 5: Wall 10: PCa concrete wall (PCa wall)
11 : Cast-in-place wall 12 : First surface 13 : Second surface 14 : Shea cotta 15 : Concrete 16 : Half PCa plate 17 : Reinforcement bar 20 : Connecting groove 33 : Consolidated horizontal bar 34 : Consolidated vertical bar 35 : Truss bar 36 : Upper end bar 37: Beam position tensile bar 40: Wall formwork 51: Building

Claims (8)

A concrete building having slabs or beams and walls having first and second surfaces parallel to the main surface and rising from the slabs or beams,
The wall includes at least a portion of a PCa concrete wall, and the PCa concrete wall has a plurality of shea cotta recessed at the bottom,
Each of the plurality of shea cotta is open to only one of the first surface and the second surface, and the plurality of shea cotta is arranged on the first surface side and the second surface side in the length direction of the wall. arranged alternately
A concrete building, wherein a lower end of said PCa concrete wall is embedded in said slab or said beam. 2. The concrete building according to claim 1, wherein the upper surface of the shea cotta has a slope that increases toward the first surface or the second surface on which the shea cotta is open. 3. The concrete building according to claim 1, wherein the area of said shea cotta on the bottom surface of said PCa concrete wall is 40 to 60% of the area of said bottom surface. The concrete structure according to any one of claims 1 to 3, wherein the shea cotta has a tapered shape that widens toward the first surface or the second surface where the shea cotta is open. building. The concrete building according to any one of claims 1 to 4, characterized in that said PCa concrete wall further has a connecting groove connecting two said shea cottas adjacent to each other. A method for constructing a concrete building having slabs or beams and walls having first and second surfaces parallel to the main surface and rising from the slabs or beams,
A PCa concrete wall that is open to only one of said first surface and said second surface and has a plurality of shea cotta at the bottom that are alternately arranged on said first surface side and said second surface side in the longitudinal direction of said wall. and
placing rebar in areas where the slabs or beams are to be built;
erecting the PCa concrete wall in place on the rebar arranged;
and placing concrete in an 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. . further comprising a cast-in-place portion in which the wall is constructed of cast-in-place concrete;
placing wall reinforcement for the cast-in-place portion around the perimeter of the PCa concrete wall after the step of erecting the PCa concrete wall;
assembling a wall form for building the cast-in-place part after pouring concrete into the slab or beam;
7. The method of constructing a concrete building according to claim 6, further comprising the step of placing concrete inside the wall formwork. 8. Constructing a concrete building according to claim 6 or claim 7, wherein the step of placing the rebar includes placing a half PCa slab at the bottom of the area where the slab or beam is to be built. Method.

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