Building

Abstract

To provide a building that can adequately resist loads acting on support members during an earthquake and that can have a simple configuration for a mat foundation including an underground beam.SOLUTION: A building 1 having a plurality of floors comprises: a first support member 21 and a second support member 41 that support a second floor portion 30; and a mat foundation 10 that supports the first support member 21 and the second support member 41 from below. The mat foundation 10 comprises a first underground beam 50 extending in a first direction in the horizontal direction, and a second underground beam 60 extending in a second direction that intersects both the first direction and the vertical direction. The second underground beam 60 has a reinforcing portion 61 which is adjacent to the first underground beam 50 in the second direction and on which the first support member 21 and the second support member 41 are placed, and a beam portion 62 which is adjacent to the reinforcing portion 61 at an opposite side to the first underground beam 50 in the second direction relative to the reinforcing portion 61. In the vertical direction, a thickness of the reinforcing portion 61 is larger than a thickness of the beam portion 62.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to buildings, in particular buildings having multiple floors. [Background technology]

[0002] A conventional building is known to have a foundation that includes an underground beam (see, for example, Patent Document 1). The underground beam described in Patent Document 1 includes a plurality of main reinforcements extending along the extension direction of the underground beam and a rectangular frame reinforcement (stirrup) surrounding the outside of the plurality of main reinforcements. The rectangular frame reinforcement is provided at a plurality of locations at intervals in the extension direction of the underground beam. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-275910 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a building with a foundation including an underground beam, it is desirable to make the underground beam have a simple structure in order to improve the workability of the foundation. In the underground beam described in Patent Document 1, it is considered that the underground beam can be simplified in structure by reducing the number of square frame reinforcements (also called "closed stirrups"). However, in Patent Document 1, if the number of square frame reinforcement bars contained in the underground beams is reduced, there is a risk that the building will not be able to adequately resist the load acting on the support members placed on the underground beams during an earthquake.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned problems, and its object is to provide a building that can adequately resist the loads acting on the support members during an earthquake and that can have a simple structure for the slab foundation including underground beams. [Means for solving the problem]

[0006] The above-mentioned objectives are achieved by a building of the present invention, which is a multi-story building comprising support members supporting the second floor and above, and a slab foundation supporting the support members from below, the slab foundation comprising a first underground beam extending along a first direction in the horizontal direction, and a second underground beam extending along a second direction intersecting both the first direction and the vertical direction, the second underground beam having a reinforcing section adjacent to the first underground beam in the second direction and on which the support member is placed, and a beam section adjacent to the reinforcing section on the opposite side of the first underground beam in the second direction relative to the reinforcing section, and in the vertical direction, the thickness of the reinforcing section is thicker than the thickness of the beam section.

[0007] In the building of the present invention, the second underground beam is provided with a reinforcing section that is thicker in the vertical direction than the beam section in the lower region of the support member where a large bending moment acts during an earthquake. The vertically thick reinforcing section has greater rigidity and strength than the beam section, and can therefore adequately resist the load acting on the support member during an earthquake. On the other hand, in the second underground beam, the bending moment acting on the beam portion during an earthquake is smaller than that on the reinforcement portion, so the cross-sectional area of ​​the beam portion can be made smaller, and as a result, the slab foundation including the underground beam can be constructed simply. As a result, the building of the present invention can adequately resist the load acting on the support members during an earthquake, and the slab foundation including the underground beams can be simply constructed.

[0008] Furthermore, the upper surfaces of the reinforcing portion and the beam portion may be at the same level in the vertical direction, and the reinforcing portion may protrude downward below the beam portion. With the above configuration, the rigidity and strength of the reinforcing part is ensured by protruding the reinforcing part downwardly beyond the beam part, while the upper surface of the second underground beam is made flat, making it possible to make the slab foundation including the underground beam have a simpler configuration.

[0009] The slab portion may also be included which constitutes the portion of the raft foundation other than the first and second underground beams, and the upper surfaces of the first and second underground beams and the slab portion may be at the same level in the vertical direction. With the above configuration, the upper surfaces of each part of the slab foundation can be made flat, making the slab foundation of a simpler configuration.

[0010] The slab foundation may further include a slab portion provided around the first underground beam or the second underground beam, and the outer edge of the slab portion may be located outside the support member in the second direction. With the above-described configuration, the periphery of the support member is reinforced by the slab portion, so that the support member can more appropriately resist loads acting on the support member during an earthquake.

[0011] The building may further include a bearing wall of the first floor including a support member, and the reinforcing portion may have a greater width in the second direction than the bearing wall of the first floor. With the above configuration, it is possible to adequately resist the load acting on the load-bearing walls on the first floor during an earthquake.

[0012] The building may further include a first floor load-bearing wall including a support member, and the first floor load-bearing wall may be located in a position that does not overlap with a load-bearing wall provided on another floor in the first direction and the second direction. With the above configuration, the force trying to pull the support member out of the second underground beam is reduced compared to when the load-bearing wall on the first floor and the load-bearing wall on another floor are in the same position (overlapping position) in both the first and second directions, so that the support member can appropriately resist the load acting on it during an earthquake.

[0013] In addition, the second underground beam includes a first main bar extending in the second direction, a second main bar arranged below the first main bar and extending in the second direction, and a reinforcing bar arranged between the first and second main bars and extending in the first direction, and the second underground beam may have a greater number of reinforcing bars arranged vertically between the first and second main bars in the reinforcement portion than in the beam portion. With the above configuration, the reinforcement section has a greater number of steel bars arranged vertically between the first main bar and the second main bar than the beam section, so that the rigidity and strength of the reinforcement section are greater and the support member can more appropriately resist the load acting on it during an earthquake.

[0014] In addition, the second underground beam may include a first main reinforcement extending in the second direction and a second main reinforcement arranged below the first main reinforcement and extending in the second direction, and the reinforcing portion may have a reinforcing bar that binds the first main reinforcement and the second main reinforcement together. With the above configuration, by binding the first main reinforcement and the second main reinforcement, the rigidity and strength of the reinforcing portion are increased, and the support member can more appropriately resist loads during an earthquake acting thereon.

[0015] There may also be a pilotis on the first floor. With the above configuration, the effects of the present invention can be further enhanced. Effect of the Invention

[0016] According to the present invention, it is possible to provide a building that can adequately resist the load acting on the support members during an earthquake and that can have a simple structure for the slab foundation including underground beams. [Brief description of the drawings]

[0017] [Figure 1] 1 is a front view showing an outline of a building according to one embodiment of the present invention. [Diagram 2] 1 is a perspective view showing an outline of a building according to one embodiment of the present invention. [Diagram 3] 1 is a foundation plan for the first floor of a building according to one embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing the section AA of FIG. [Diagram 5] FIG. 2 is a schematic reinforcement diagram of a slab foundation included in a building according to one embodiment of the present invention. [Figure 6] FIG. 2 is a diagram showing the distribution of bending moments acting on a slab foundation included in a building according to one embodiment of the present invention. [Figure 7] FIG. 5 is a cross-sectional view corresponding to FIG. 4 of a mat foundation according to a comparative example. [Figure 8] FIG. 8 is a cross-sectional view showing the cross section BB of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention (hereinafter, the present embodiment) will be described in detail below with reference to the preferred embodiment shown in the accompanying drawings. In addition, the drawings show each component somewhat simplified and schematic in order to make the explanation easier to understand, and the size (dimensions) of each component and the intervals between components shown in the drawings are different from the actual ones. In addition, unless otherwise specified, the material and shape of each member used to implement the present invention can be arbitrarily set depending on the application of the present invention and the state of the art at the time of implementing the present invention. Furthermore, the present invention includes its equivalents.

[0019] In this specification, one horizontal direction is defined as a first direction, and a second direction intersecting (orthogonal to) both the first direction and the vertical direction is defined as a second direction. For example, the first direction corresponds to the girder direction, and the second direction corresponds to the span direction. In this specification, "orthogonal" and "vertical" include the range of error permitted in the technical field to which the present invention pertains. For example, "orthogonal" and "vertical" mean within a range of less than ±10° from strict orthogonal or vertical, and the error from strict orthogonal or vertical is preferably 5° or less, and more preferably 3° or less.

[0020] <<Overview of the building according to this embodiment>> A building according to this embodiment (hereinafter, building 1) will be described with reference to FIGS. The building 1 includes buildings for various purposes, such as houses, offices, stores, facilities such as hospitals or schools, and buildings within factories. The building 1 is, for example, a multi-story building (a two-story building in this embodiment) as shown in FIG. The multiple columns (first support members 21 and bearing walls 40) included in the first floor portion 20 rise up from the slab foundation 10. The upper surface of the slab foundation 10 is a horizontal, flat surface, in other words, a surface without steps. This allows people, cars, etc. to move smoothly between the pilotis 22 and the external space. In the example shown in Figure 1, all of the spaces between adjacent columns (first support member 21 and load-bearing wall 40) are openings, but for example, an exterior wall (load-bearing wall, etc.) may be placed in at least one of the openings between adjacent columns, and the opening may be blocked.

[0021] As shown in FIG. 1, the building 1 has a slab foundation 10, a first floor portion 20 located on the slab foundation 10, and a second floor portion 30 located on the first floor portion 20. The slab foundation 10 supports the first floor portion 20 from below, and the upper surface 10a of the slab foundation 10 is a horizontal, flat surface as described above. As shown in Figures 1 and 2, the first floor portion 20 has multiple columns, including a first support member 21 (corresponding to a support member) that supports the second floor portion 30 and a load-bearing wall 40 including a second support member 41 (corresponding to a support member) that supports the second floor portion 30, and further has a pilotis 22, which is a space surrounded by these columns (the first support member 21 and the second support member 41). 2, the second floor portion 30 has a floor wall, a side wall (exterior wall), and a ceiling wall, and separates an indoor space surrounded by the floor wall, the side wall, and the ceiling wall from an external space. The second floor portion 30 has, for example, a rectangular parallelepiped shape with a first horizontal direction as a longitudinal direction, and has second floor load-bearing walls 31 along each of the long and short sides at each of the four corners when viewed from above in the vertical direction.

[0022] <Details of the first floor structure> As shown in Fig. 1, two of the multiple columns (first support members 21 and bearing walls 40) included in the first floor section 20 are disposed at a distance from each other so as to face each other in the second direction, constituting a pair of columns. Each of the pair of columns is disposed at each of both ends of the second floor section 30 in the second direction. In this embodiment, the first floor section 20 has a plurality of pairs of columns, and the plurality of pairs of columns are arranged at intervals along the first direction. In this embodiment, as shown in FIG. 1, the first floor portion 20 has multiple (8) columns, including multiple (4) first support members 21 and multiple (4) load-bearing walls 40, and four sets of columns, each consisting of a pair of first support members 21 facing each other in the second direction and a pair of load-bearing walls 40 facing each other in the second direction, are arranged at intervals along the first direction. More specifically, as shown in FIG. 2, of the four sets of columns, a pair of columns located at both ends in the first direction is composed of a pair of first support members 21, and of the four sets of columns, a pair of columns located other than both ends in the first direction (at the center) is composed of a pair of load-bearing walls 40.

[0023] It should be noted that the above configuration is merely an example, and the number of columns, the number of bearing walls 40 among the columns, and the positions of the bearing walls 40 are not limited to the above configuration. For example, the first floor portion 20 may have only the bearing walls 40 without having the first support members 21. More specifically, instead of the multiple (four) first support members 21 shown in FIG. 1, multiple (four) bearing walls 40 may be arranged, that is, all of the multiple columns included in the first floor portion 20 may be the bearing walls 40.

[0024] The multiple (four) first support members 21 are provided below each of the four corners of the second floor portion 30, that is, below the bearing walls 31 of the second floor shown in FIG. On the other hand, the multiple (four) load-bearing walls 40 are arranged so as not to be below the load-bearing walls 31 on the second floor; in other words, in the first and second directions, they are positioned so as not to overlap with the load-bearing walls 31 arranged on another floor.

[0025] The first support member 21 supports the second floor and above (the second floor portion 10 in this embodiment), and is made of, for example, steel, more specifically, shaped steel (H-shaped steel, channel steel, etc.) or steel pipes, etc. The first support member 21 is fixed to the mat foundation 10 by anchor bolts (not shown).

[0026] As shown in Figure 2, the load-bearing wall 40 is composed of a pair (two) of adjacent second support members 41 arranged at a distance in the second direction, and a connecting member 42 connecting the pair of second support members 41. The load-bearing wall 40 may have a configuration similar to that of a known load-bearing wall, for example, a ladder-type load-bearing wall having excellent energy absorption properties during earthquakes, as disclosed in JP 2014-47469 A or JP 2019-157518 A, etc. The interval between the pair of second support members 41 in the second direction is preferably, for example, 0.25 modules or 0.5 modules, and one module is, for example, 910 mm.

[0027] The bearing wall 40 is fixed to the raft foundation 10 by anchor bolts 17 (see FIG. 4). More specifically, an anchor bolt 17 is disposed for each of a pair of second support members 41, and each of the pair of second support members 41 is fixed to the raft foundation 10 by the corresponding anchor bolt 17.

[0028] <Details of the raft foundation structure> As shown in Fig. 2, the raft foundation 10 supports the first support member 21 and the second support member 41 of the first floor portion 20 from below. Note that in Fig. 2, the slab portion 70 of the raft foundation 10 is not shown. More specifically, as shown in Figure 3, the slab foundation 10 comprises a pair (two) first ground beams 50 extending along a first direction, a plurality (four) second ground beams 60 extending along a second direction, and a slab portion 70 which constitutes the part of the slab foundation 10 other than the first ground beams 50 and the second ground beams 60. The first underground beam 50, the second underground beam 60, and the slab portion 70 are integrally constructed from concrete containing reinforcing bars therein. In this embodiment, the slab foundation 10 has a rectangular shape in plan view, for example, as shown in FIG.

[0029] A pair of first underground beams 50 are arranged at a distance from each other in the second direction and are located at both ends of the slab foundation 10 in the second direction, more specifically, in an area inner than the outer edge of the slab foundation 10 in the second direction. A plurality (four) of second ground beams 60 are disposed between a pair of first ground beams 50 in the second direction, and are arranged at intervals along the first direction. More specifically, two of the multiple second ground beams 60 are located at both ends in the first direction of the slab foundation 10, more specifically, in an area inside the outer edge of the slab foundation 10 in the first direction, and together with a pair of first ground beams 50, form a rectangular frame along the outer edge of the slab foundation 10. The remaining second ground beams 60 of the multiple (four) second ground beams 60 are located within that rectangular frame.

[0030] As shown in Figure 3, the second underground beam 60 has a reinforcing portion 61 adjacent to the first underground beam 50 in the second direction, and a beam portion 62 adjacent to the reinforcing portion 61 on the opposite side of the first underground beam 50 in the second direction relative to the reinforcing portion 61. More specifically, the reinforcing parts 61 are located at both ends of the second underground beam 60 in the second direction, and the beam part 62 is located between those reinforcing parts 61. In other words, the second underground beam 60 is composed of the beam part 62 and a pair of reinforcing parts 61 located on both sides of the beam part 62 in the second direction. In FIG. 3, for ease of explanation, the reinforcing portion 61 and the beam portion 62 are illustrated as separate parts surrounded by a two-dot chain line, but in reality, the reinforcing portion 61 and the beam portion 62 are continuously integrated.

[0031] On each of the reinforcing portions 61, as shown in FIG. 3, the first support member 21 or the bearing wall 40 is placed. More specifically, as shown in Figure 3, the first support member 21 is placed on the first underground beam 50 and a reinforcement portion 61 adjacent to the first underground beam 50, and is fixed to at least the reinforcement portion 61 by an anchor bolt not shown. It should be noted that the first support member 21 may be placed only on the reinforcing portion 61 without being placed across the first underground beam 50 and the reinforcing portion 61.

[0032] As shown in FIG. 3, the load-bearing wall 40 is placed on the first underground beam 50 and a reinforcing portion 61 adjacent to the first underground beam 50, and is fixed to the reinforcing portion 61 by anchor bolts 17 (see FIG. 4). More specifically, as shown in FIG. 4, at least one of the second support members 41, more specifically, at least the inner second support member 41 in the second direction of the pair of second support members 41, is placed on the reinforcing portion 61, and the second support member 41 is fixed to the reinforcing portion 61 by an anchor bolt 17. In the example shown in Figure 4, the outer second support member 41 in the second direction of the pair of second support members 41 is fixed to the first underground beam 50, but this is not limited to this, and both of the pair of second support members 41 may be placed on the reinforcing portion 61 and fixed to the reinforcing portion 61.

[0033] The slab portion 70 constitutes the portion of the slab foundation 10 other than the first ground beam 50 and the second ground beam 60, and is provided around the first ground beam 50 or the second ground beam 60. As shown in Fig. 3, for example, the slab portion 70 has a plurality (three) of rectangular inner slabs 71 and a rectangular frame-shaped outer slab 72. Multiple (three) inner slabs 71 are provided inside a rectangular frame consisting of first ground beams 50 and second ground beams 60 arranged along the outer edge of the foundation 10, and are each located between adjacent second ground beams 60 in the first direction. The outer slab 72 is located outside the rectangular frame in the horizontal direction (first direction and second direction) and is provided so as to surround the rectangular frame. In other words, the outer slab 72 forms a rectangular frame larger than the rectangular frame formed by the first underground beams 50 and the second underground beams 60. In FIG. 3, the areas corresponding to the inner slab 71 and the outer slab 72 are marked with a dot pattern.

[0034] As shown in FIG. 4, the outer edge of the slab portion 70 in the second direction is located outside the bearing wall 40 in the second direction, and more specifically, the outer edge of the outer slab 72 in the second direction is located outside the second support member 41 located outside in the second direction among a pair of second support members 41 included in the bearing wall 40. In the second direction, the distance D (see FIG. 4) from the outer edge of the outer slab 72 to the second support member 41 located outside in the second direction is preferably 100 mm to 500 mm, more preferably 200 mm to 400 mm that can ensure the embedment depth of the anchor bolt 17 or more, and even more preferably 300 mm to 400 mm that can ensure the height of the first underground beam 50 or the second underground beam 60 (specifically, the reinforcing portion 61). The embedment depth of the anchor bolt 17 corresponds to the vertical length of the portion of the anchor bolt 17 embedded in the first underground beam 50 or the reinforcing portion 61. Furthermore, the height of the first underground beam 50 or the second underground beam 60 corresponds to the thickness of the first underground beam 50 or the second underground beam 60 in the vertical direction. Note that the number and external shapes of the inner slabs 71 and outer slabs 72 shown above are merely examples and are not limited to these, and may vary depending on the placement positions and numbers of the first underground beams 50 and second underground beams 60 in the slab foundation 10.

[0035] (Regarding reinforcement in slab foundations) Next, the positions of the reinforcing bars extending inside the slab 10 (reinforcing bars inside the slab 10) will be described with reference to Figs. As shown in Figure 5, the slab foundation 10 is composed of a reinforcing bar section 11 consisting of multiple reinforcing bars extending in a first direction, a reinforcing bar section 12 consisting of multiple reinforcing bars extending in a second direction, and a concrete section (not shown) arranged around the reinforcing bar sections 11 and 12.

[0036] In Figure 5, the main reinforcements 13, 15 described later are shown with thick solid lines, and the slab reinforcements 14, 16 described later are shown with thin dashed lines, but this is for ease of explanation, and in reality, the main reinforcements 13, 15 and the slab reinforcements 14, 16 may be of the same material or the same diameter, or they may be different. For example, the main reinforcements 13, 15 and the slab reinforcements 14, 16 may each be made of steel bars of the same material but different diameters. In addition, Figure 5 only shows the slab reinforcements 14, 16 around the main reinforcements 13, 15, but in reality, there are slab reinforcements 14, 16 that are not shown, and it is assumed that the slab reinforcements 14, 16 are arranged throughout the entire slab foundation 10. In addition, in FIG. 4, for ease of explanation, the main reinforcements 13 are indicated by filled circles, and the slab reinforcements 14 are indicated by open circles.

[0037] More specifically, the reinforcing bar portion 11 is composed of a plurality of main reinforcements 13 and a plurality of slab reinforcements 14 extending in the first direction, as shown in Fig. 5. The main reinforcements 13 and the slab reinforcements 14 are arranged at predetermined intervals along the second direction, for example, at a pitch of 200 mm.

[0038] More specifically, as shown in FIG. 5, the main reinforcement 13 is disposed in an area corresponding to the first underground beam 50, and extends from one end to the other end of the raft foundation 10 in the first direction. The slab reinforcement 14 is arranged in an area where the main reinforcement 13 is not arranged, and extends from one end to the other end in the first direction.

[0039] As shown in Fig. 4, multiple main reinforcements 13 (black circles in Fig. 4) are arranged in the vertical direction (two in Fig. 4). The main reinforcements 13 are configured as so-called double reinforcement, consisting of upper main reinforcements 13 (upper end reinforcements) and lower main reinforcements 13 (lower end reinforcements). The main reinforcements 13 form a double reinforcement arrangement from one end to the other end of the slab foundation 10 in the first direction. As for the slab reinforcement 14 (white circles in Fig. 4), as shown in Fig. 4, the slab reinforcement 14 passing through the reinforcing portion 61 constitutes double reinforcement from one end to the other end of the slab foundation 10 in the first direction. On the other hand, the slab reinforcement 14 passing through the area other than the reinforcing portion 61, i.e., the slab reinforcement 14 passing through the beam portion 62 and the outer slab 72 constitutes so-called single reinforcement, consisting only of the upper slab reinforcement 14 (upper end reinforcement), from one end to the other end of the slab foundation 10 in the first direction.

[0040] As shown in Fig. 5, the reinforcing bar portion 12 is composed of a plurality of main reinforcements 15 and a plurality of slab reinforcements 16 extending in the second direction. The main reinforcements 15 and the slab reinforcements 16 are arranged at predetermined intervals along the first direction, for example, at a pitch of 200 mm. More specifically, as shown in FIG. 5, the main reinforcement 15 is disposed in an area corresponding to the second underground beam 60, and extends from one end to the other end of the raft foundation 10 in the second direction. The slab reinforcement 16 is arranged in an area where the main reinforcement 15 is not arranged, and extends from one end of the slab foundation 10 to the other end in the second direction.

[0041] As shown in Fig. 4, the number of main reinforcements 15 in the vertical direction varies depending on the position in the second direction. More specifically, at both ends of the slab foundation 10 in the second direction, the main reinforcements 15 form double reinforcement, but at other ends (the center), the main reinforcements 15 form single reinforcement. More specifically, of the two main reinforcements 15 aligned vertically, the upper main reinforcement 15 extends from one end to the other end of the slab foundation 10 in the second direction, while the lower main reinforcement 15 extends in the second direction only to both ends of the slab foundation 10. Therefore, at both ends of the slab foundation 10 in the second direction, the main reinforcements 15 form double reinforcement, but at other ends (the center), the main reinforcements 15 form single reinforcement. In this embodiment, as shown in Figure 4, in the area of ​​the beam portion 62 adjacent to the reinforcing portion 61, the reinforcing portion 61, the first underground beam 50, and the outer slab 72, the main reinforcement 15 forms double reinforcement, and in the area of ​​the beam portion 62 not adjacent to the reinforcing portion 61, the main reinforcement 15 forms single reinforcement. In this embodiment, as shown in FIG. 4, the main reinforcements 13 and slab reinforcements 14 extending in the first direction are located between the upper and lower main reinforcements 15 in the second direction.

[0042] In the following explanation, as shown in Figure 4, the part of the upper main reinforcement 15 that is included in the second underground beam 60 will be referred to as the first main reinforcement 63, the part of the lower main reinforcement 15 that is included in the second underground beam 60 will be referred to as the second main reinforcement 64, and the part of the slab reinforcement 14 extending in the first direction that is included in the second underground beam 60 will be referred to as steel bar 65 (white circle in Figure 4). That is, the second underground beam 60 includes a first main reinforcement 63 extending in the second direction, a second main reinforcement 64 arranged below the first main reinforcement 63 and extending in the second direction, and a steel bar 65 arranged between the first main reinforcement 63 and the second main reinforcement 64 and extending in the first direction.

[0043] As with the main reinforcement 15, the slab reinforcement 16 forms double reinforcement at both ends of the slab foundation 10 in the second direction, but other than at both ends (the center), the slab reinforcement 16 forms single reinforcement. For this reason, while Fig. 4 shows the cross-sectional shape of the slab foundation 10 cut at a position corresponding to the main reinforcement 15, the cross-sectional shape of the slab foundation 10 will be the same even if the cutting position is moved in the first direction and the slab foundation 10 is cut at a position corresponding to the slab reinforcement 16. In other words, the cross-sectional shape of the slab foundation 10 perpendicular to the first direction is the same from one end of the slab foundation 10 to the other end in the first direction.

[0044] In the above description, the cross-sectional shape of the slab foundation 10 perpendicular to the first direction (see FIG. 4) is the same from one end of the slab foundation 10 to the other end in the first direction, but this is not limited to this. In other words, when the slab foundation 10 is cut at a position corresponding to the slab reinforcement 16, the cross-sectional shape may be different from that in FIG. 4, for example, the cross-sectional shape may be one in which there are no parts protruding below the first underground beam 50 and the reinforcing part 61.

[0045] (About the structure of the slab foundation around the load-bearing wall on the first floor) Next, the configuration of the slab foundation 10 around the load-bearing wall 40 on the first floor will be described in more detail with reference to FIG. As shown in FIG. 4, the foundation 10 has, in order from the inside to the outside in the second direction, a beam portion 62, a reinforcing portion 61, a first underground beam 50, and an outer slab 72.

[0046] The main reinforcement bars 15 extending in the second direction pass through the interior of each of the beam section 62, the reinforcing section 61, the first underground beam 50, and the outer slab 72, and the vertical spacing between the upper and lower main reinforcement bars 15 is widest in the lower region of the load-bearing wall 40, i.e., the first underground beam 50 and the end of the reinforcing section 61 facing the first underground beam 50.

[0047] The upper main reinforcement 15 is located vertically above the lower main reinforcement 15, and extends horizontally in a straight line through the beam portion 62, the reinforcing portion 61, the first underground beam 50, and the outer slab 72, in that order, from the inside to the outside in the second direction. It should be noted that the portion of the upper main reinforcement 15 that is included in the second underground beam 60 corresponds to the first main reinforcement 63, as described above.

[0048] On the other hand, the lower main reinforcement 15 extends from the inside to the outside in the second direction while having multiple bent portions, and protrudes most downward in the lower region of the bearing wall 40. More specifically, as shown in Figure 4, the lower main reinforcement 15 has, from the inside to the outside in the second direction, a first horizontal portion located in the beam portion 62, a first inclined portion located in the reinforcing portion 61, a second horizontal portion located across the reinforcing portion 61 and the first underground beam 50, a second inclined portion located across the first underground beam 50 and the outer slab 72, and a third horizontal portion located on the outer slab 72.

[0049] The first horizontal portion extends horizontally from the end region of the beam portion 62 in the second direction toward the outside in the second direction. The first inclined portion extends from the outer end of the first horizontal portion in the second direction toward the outside in the second direction, and inclines downward as it progresses in the second direction. The second horizontal portion extends horizontally from the outer end of the first inclined portion in the second direction toward the outside in the second direction. The second inclined portion extends from the outer end of the second horizontal portion in the second direction toward the outside in the second direction, and inclines upward as it progresses in the second direction. The third horizontal portion extends horizontally from the outer end of the second inclined portion in the second direction toward the outside in the second direction. In addition, of the lower main reinforcement 15, the first horizontal portion, the first inclined portion, and the portion of the second horizontal portion on the reinforcing portion 61 side correspond to the second main reinforcement 64.

[0050] To further explain the relationship between the first main reinforcement 63 and the second main reinforcement 64, as shown in Figure 4, the spacing between the first main reinforcement 63 and the second main reinforcement 64 is wider in the vertical direction in the reinforcing portion 61 than in the beam portion 62. More specifically, the reinforcing portion 61 has a first region 67 located below the bearing wall 40, and a second region 68 located inside in the second direction (toward the beam portion 62) with respect to the first region 67. In the vertical direction, the spacing between the first main reinforcement 63 and the second main reinforcement 64 is constant in the first region 67 from one end to the other end of the first region 67 in the second direction, and in the second region 68, the spacing is narrower than that in the first region 67 and narrows toward the inside in the second direction (toward the beam portion 62). In the beam portion 62, the spacing between the first main reinforcements 63 and the second main reinforcements 64 in the vertical direction is constant from one end to the other end of the beam portion 62 in the second direction.

[0051] Next, regarding the main reinforcements 13 and slab reinforcements 14 extending in the first direction, as shown in FIG. 4, the main reinforcements 13 (shown by black circles in FIG. 4) are arranged between the upper main reinforcements 15 and the lower main reinforcements 15, and multiple main reinforcements (two in this embodiment) are arranged in the vertical direction. Of the slab reinforcement 14 (shown by a white circle in FIG. 4), the portion included in the second underground beam 60, that is, the reinforcing bar 65, is disposed between the first main reinforcement 63 and the second main reinforcement 64. More specifically, in the second underground beam 60, the reinforcing portion 61 has a greater number of reinforcing bars 65 arranged vertically between the first main reinforcement 63 and the second main reinforcement 64 than the beam portion 62. In this embodiment, the reinforcing portion 61 has a plurality (two) reinforcing bars 65 arranged vertically, while the beam portion 62 has a single reinforcing bar 65 arranged vertically. Of the slab reinforcement 14, one slab reinforcement 14 passing through the outer slab 72 is arranged in the vertical direction, as shown in Figure 4, and is arranged adjacent to the upper main reinforcement 15 at a position below the upper main reinforcement 15.

[0052] In the slab foundation 10, concrete portions (not shown) are provided around the upper and lower main reinforcements 15 so as to conform to the respective shapes of the upper and lower main reinforcements 15. That is, in the slab foundation 10, the cross-sectional shape perpendicular to the first direction is shaped according to the shapes of the upper and lower main reinforcements 15 as shown in FIG.

[0053] More specifically, the thickness of the first underground beam 50 in the vertical direction is thicker than the thickness of the outer slab 72, as shown in FIG. 4, and is preferably 300 mm to 400 mm. In addition, the width of the first underground beam 50 in the second direction is, for example, 400 mm.

[0054] As shown in FIG. 4, in the second underground beam 60, the thickness of the reinforcing portion 61 is greater than the thickness of the beam portion 62 in the vertical direction, and the reinforcing portion 61 forms a so-called haunch portion.

[0055] More specifically, in the reinforcing portion 61, the thickness of the first region 67 in the vertical direction is thicker than the thickness of the second region 68, is constant from one end to the other end of the first region 67 in the second direction, and is the thickest in the reinforcing portion 61. In this embodiment, the thickness of the first region 67 of the reinforcing portion 61 in the vertical direction is preferably, for example, 300 to 400 mm. The thickness of the second region 68 becomes thinner in the vertical direction toward the inside in the second direction (toward the beam portion 62). The thickness of the beam portion 62 in the vertical direction is thinner than that of the second region 68, and is constant from one end to the other end of the beam portion 62 in the second direction.

[0056] As shown in FIG. 4, the upper surfaces 61a, 62a of the reinforcing portion 61 and the beam portion 62 are at the same level in the vertical direction and form a flat upper surface 60a of the second underground beam 60. The upper surface 60a of the second underground beam 60 is at the same vertical level as the upper surface 50a of the first underground beam 50 and the upper surface 70a of the slab portion 70, as shown in Figure 4, and these upper surfaces 50a, 60a, 70a form the flat upper surface 10a of the slab foundation 10 (see Figure 1).

[0057] The reinforcing portion 61 protrudes downward further than the beam portion 62, and protrudes downward in the vertical direction to the same level as the first underground beam 50. Additionally, the lower surfaces of the beam portions 62 and the outer slabs 72 are at the same level in the vertical direction.

[0058] In the second direction, the reinforcing portion 61 has a width greater than that of the first floor load-bearing wall 40; more specifically, in the second direction, the combined width of the first region 67 and the second region 68 of the reinforcing portion 61 is greater than the width of the first floor load-bearing wall 40. In addition, in the second direction, it is preferable that the width of the first region 67 is longer than the width of the load-bearing wall 40 of the first floor, and it is even more preferable that the widths of each of the first region 67 and the second region 68 of the reinforcing portion 61 are longer than the width of the load-bearing wall 40. The width of the reinforcing portion 61 in the second direction is preferably, for example, 500 mm or more.

[0059] In addition, in the first direction, the reinforcing portion 61 is longer than the bearing wall 40 of the first floor.

[0060] The reinforcing portion 61 may have a reinforcing bar 66 that binds the first main bars 63 and the second main bars 64 together, as shown in FIG. Further, although not shown in FIG. 4, the reinforcing portion 61 may have a reinforcing bar (cap tie) (not shown) that binds the first main bars 63 adjacent to each other in the first direction. The reinforcing bars 66 and the cap ties are formed, for example, by bending both ends of a reinforcing bar. The reinforcing bars 66 and the cap ties may be of the same material or have the same diameter as the slab bars 14, 16, or may be of different materials. In addition to the above-mentioned reinforcing bars 66, the slab foundation 10 may have reinforcing bars (not shown) that tie together the upper main reinforcements 13 (upper end reinforcements) and the lower main reinforcements 13 (lower end reinforcements) that extend in the first direction. In addition to the above-mentioned cap ties, the slab foundation 10 may have cap ties (not shown) that tie together the upper first main reinforcements 63 that are adjacent to each other in the second direction.

[0061] <About the construction procedure for raft foundations> An example of a construction procedure for the mat foundation 10 of this embodiment will be described with reference to FIG. First, a hole is dug in the planned location of the slab foundation 10 according to the shape of the slab foundation 10, crushed stone is poured into the hole, and the bottom of the hole is compacted. Next, the bottom of the hole is covered with a moisture-proof sheet, and concrete is poured from above the moisture-proof sheet into the planned location of the anchor bolt 17, and an anchor frame (not shown) supporting the anchor bolt 17 is fixed to the poured concrete. After that, the process moves to the reinforcement process.

[0062] The reinforcement process involves first placing the lower main reinforcements 15 and slab reinforcements 16 of the main reinforcements 15 and slab reinforcements 16 extending in the second direction, and then placing the lower main reinforcements 13 and slab reinforcements 14 of the main reinforcements 13 and slab reinforcements 14 extending in the first direction. Next, of the main reinforcements 13 and slab reinforcements 14 extending in the first direction, the upper main reinforcements 13 and slab reinforcements 14 are placed, and then, of the main reinforcements 15 and slab reinforcements 16 extending in the second direction, the upper main reinforcements 15 and slab reinforcements 16 are placed. Then, by placing the reinforcing bars 66 and cap ties (not shown), a series of reinforcement arrangement processes is completed. Next, the formwork is assembled, concrete is poured into the formwork, and the formwork is dismantled, completing the series of construction steps for the raft foundation 10.

[0063] <<About the action and effect of the building according to this embodiment>> FIG. 6 shows a bending moment diagram acting on the raft foundation 10 in this embodiment. More specifically, Figure 6 shows the distribution of bending moments acting on the slab foundation 10 when a horizontal load in the second direction, more specifically, a horizontal load from the right side to the left side of Figure 6, acts on the load-bearing walls 40 located at each of both ends of the slab foundation 10 in the second direction.

[0064] In this embodiment, as shown in Figure 6, the bending moment acting on the slab foundation 10 is greatest in the lower region (corresponding to the first region 67) of the inner second support member 41 in the second direction of the pair of second support members 41, and decreases from the lower region toward the inside in the second direction. Note that, while Fig. 6 shows an example in which a horizontal load acts from the right side to the left side in Fig. 6, the same applies when a horizontal load acts from the left side to the right side in Fig. 6. In other words, the direction of the bending moment acting on the slab 10 is simply reversed, and the bending moment acting on the slab 10 becomes largest in the lower region of the inner second support member 41 in the second direction of the pair of second support members 41.

[0065] 6 is an example in which a horizontal load acts in the second direction on the bearing walls 40 arranged at both ends of the slab foundation 10 in the second direction, but the same applies to a case in which a horizontal load acts in the second direction on the first support members 21 arranged at both ends of the slab foundation 10 in the second direction. That is, the bending moment acting on the slab foundation 10 is greatest in the lower region of the first support members 21, and decreases from that lower position toward the inside in the second direction.

[0066] In the building 1 of this embodiment, the second underground beam 60 is provided with a reinforcing portion 61 that is thicker in the vertical direction than the beam portion 62 in the lower region of the first support member 21 and the second support member 41 where a large bending moment acts during an earthquake. The vertically thick reinforcing portion 61 has a greater rigidity and strength than the beam portion 62, and can therefore adequately resist the load acting on the first support member 21 and the second support member 41 during an earthquake.

[0067] More specifically, the first region 67 of the reinforcing portion 61 is subjected to the largest bending moment and is therefore the thickest in the vertical direction, while the second region 68 has a vertical thickness that varies in accordance with the change (decrease) in the bending moment as it moves inward in the second direction (toward the beam portion 62). In this way, by configuring the mat foundation 10 in accordance with the magnitude of the bending moment acting on the mat foundation 10, the first support member 21 and the second support member 41 can appropriately resist the load acting on them during an earthquake.

[0068] Moreover, in the building 1 of this embodiment, the slab foundation 10 can be simply configured. A more detailed explanation will be given using a comparative example shown in FIGS. As shown in Figure 7, the foundation 110 of the comparative example has a first underground beam 150 extending along a first direction, a second underground beam 160 extending along a second direction, and a rising portion 119 rising from the first underground beam 150 and the second underground beam 160. The thickness of the second underground beam 160 in the vertical direction is constant from one end to the other end in the second direction. The second underground beam 160 has a plurality of main reinforcements 115 extending in the second direction therein, and the plurality of main reinforcements 115 are arranged vertically one above the other. Both the upper main reinforcements 115 and the lower main reinforcements 115 extend from one end to the other end of the second underground beam 160 in the second direction. Closed square frame-shaped reinforcing bars 118 (also called closed stirrups) are provided around the upper and lower main bars 115 so as to surround the multiple main bars 115, and the reinforcing bars 118 are provided at intervals at a predetermined pitch in the second direction. A bearing wall 40 is placed on the rising portion 119.

[0069] In contrast, in the building 1 of this embodiment, by appropriately grasping the bending moment acting on the slab foundation 10 during an earthquake, a simpler slab foundation 10 is realized compared to the foundation 110 of the comparative example. More specifically, in the slab foundation 10 of this embodiment, the beam portion 62 does not require as much strength as the reinforcing portion 61, so it is possible to reduce the number of main reinforcements 15 arranged in the vertical direction. This allows the cross-sectional area of ​​the beam portion 62 to be reduced, resulting in a simpler structure than the foundation 110 of the comparative example. Furthermore, in the slab foundation 10, since the beam portion 62 does not require as much strength as the reinforcing portion 61, reinforcing bars equivalent to the reinforcing bars 118 of the foundation 110 are not provided in the beam portion 62, thereby achieving a simpler configuration than the foundation 110 of the comparative example. Furthermore, in the slab foundation 10, there is no portion equivalent to the rising portion 119 of the foundation 110, and the thickness of the reinforcing portion 61 in the vertical direction is made thicker than the thickness of the beam portion 62, thereby achieving a simpler configuration than the foundation 110 of the comparative example.

[0070] As described above, the building 1 of this embodiment can appropriately resist earthquake loads acting on the first support member 21 and the second support member 41, and the slab foundation 10 including the first underground beam 50 and the second underground beam 60 can be simply configured.

[0071] In this embodiment, the upper surfaces 61a, 62a of the reinforcing portion 61 and the beam portion 62 are at the same level in the vertical direction as shown in Fig. 4. The reinforcing portion 61 protrudes downward further than the beam portion 62. With the above-mentioned configuration, the rigidity and strength of the reinforcing portion 61 is ensured by protruding the reinforcing portion 61 downwardly beyond the beam portion 62, while the upper surface 60a of the second underground beam 60 is made flat, making it possible to make the slab foundation 10 including the first underground beam 50 and the second underground beam 60 have a simpler configuration.

[0072] In addition, in this embodiment, as shown in Figure 3, the slab portion 70 constitutes the part of the slab foundation 10 other than the first underground beam 50 and the second underground beam 60, and the upper surfaces 50a, 60a, 70a of the first underground beam 50, the second underground beam 60, and the slab portion 70 are at the same level in the vertical direction, as shown in Figure 4. With the above-mentioned configuration, the upper surface 10a (see FIG. 1) of the raft foundation 10 can be made flat, so that the raft foundation 10 can have a simpler configuration.

[0073] Furthermore, when the cross-sectional shape perpendicular to the first direction of the slab foundation 10 is the same from one end of the slab foundation 10 in the first direction to the other end, force is transmitted in the first direction from the second underground beam 60 to the slab portion 70. This makes it possible to increase the effective width in the first direction of the force resisting a force (pulling force) that tries to pull the second support member 41 out of the second underground beam 60 during an earthquake. 7, in the comparative example, the second support member 41 rises from the rising portion 119, so the effective width in the first direction is limited to the width of the rising portion 119. On the other hand, if the cross-sectional shape perpendicular to the first direction of the slab foundation 10 is the same from one end of the slab foundation 10 to the other end in the first direction, the effective width in the first direction can be made large. This allows the offsetting load due to the weight of the slab section 70 to be large as a force against the pull-out force, and allows the force due to the slab reinforcement 16 of the slab section 70 to contribute in addition to the force due to the main reinforcement 15 of the second underground beam 60. Furthermore, by increasing the above-mentioned effective width, the reinforcement structure of the reinforcement portion 61 can be further simplified; for example, the vertical thickness of the reinforcement portion 61 can be reduced, and the diameters of the first main reinforcement 63 and the second main reinforcement 64 included in the reinforcement portion 61 can be reduced.

[0074] In this embodiment, the outer edge of the slab portion 70, more specifically, the outer edge of the outer slab 72, is located outside the first support member 21 and the second support member 41 in the second direction, as shown in FIG. With the above-mentioned configuration, the slab portion 70 reinforces the areas around the first support member 21 and the second support member 41, so that the first support member 21 and the second support member 41 can more appropriately resist loads acting on them during an earthquake.

[0075] In this embodiment, as shown in Fig. 2, the building 1 includes a first floor bearing wall 40 including a second support member 41. As shown in Fig. 4, the reinforcing portion 61 has a larger width in the second direction than the first floor bearing wall 40. The above-described configuration allows the first-floor bearing wall 40 to adequately resist an earthquake load acting on the wall, more specifically, a horizontal load in the second direction.

[0076] In this embodiment, as shown in FIG. 2, the bearing wall 40 on the first floor is located so as not to overlap with the bearing wall 31 provided on the second floor (another floor) in the first and second directions. With the above configuration, the force trying to pull the second support member 41 out of the second underground beam 60 (more specifically, the reinforcement portion 61) is reduced compared to when the first floor load-bearing wall 40 and the second floor load-bearing wall 31 are in the same position (overlapping position) in both the first and second directions.

[0077] More specifically, when the load-bearing walls 40 and 31 are in the same position in both the first and second directions, the structure is equivalent to having a vertically long load-bearing wall that rises from the upper surface 10a of the foundation 10 to the ceiling wall of the second floor, and during an earthquake, such a long load-bearing wall is subjected to a load equal to the sum of the loads on both the load-bearing wall 40 of the first floor and the load-bearing wall 31 of the second floor, with the result that a larger bending moment is applied to the first region 67 located below the load-bearing wall 40 of the first floor. In contrast, in the building 1 of this embodiment, the first floor load-bearing wall 40 and the second floor load-bearing wall 31 are located in positions that do not overlap in the first and second directions, so that the first region 67 only receives a bending moment based on the load acting on the first floor load-bearing wall 40, and is therefore able to adequately resist loads during an earthquake. Furthermore, since the bending moment acting on the first region 67 located below the first floor load-bearing wall 40 is further reduced compared to when the first floor load-bearing wall 40 and the second floor load-bearing wall 31 are in the same position in both the first and second directions, the reinforcing structure of the reinforcing portion 61 can be further simplified, and as a result, the slab foundation 10 can be configured more simply.

[0078] The second underground beam 60 includes a first main reinforcement 63 extending in the second direction, a second main reinforcement 64 disposed below the first main reinforcement 63 and extending in the second direction, and a reinforcing bar 65 disposed between the first main reinforcement 63 and the second main reinforcement 64 and extending in the first direction. In the second underground beam 60, the reinforcing portion 61 has a larger number of reinforcing bars 65 lined up vertically between the first main reinforcement 63 and the second main reinforcement 64 than the beam portion 62. With the above-mentioned configuration, the reinforcement portion 61 has a greater number of steel bars 65 arranged vertically between the first main reinforcement 63 and the second main reinforcement 64 than the beam portion 62, so that the rigidity and strength of the reinforcement portion 61 are increased and the reinforcement portion 61 can more appropriately resist the load acting on the first support member 21 and the second support member 41 during an earthquake.

[0079] Further, the reinforcing portion 61 has a reinforcing bar 66 that binds the first main bar 63 and the second main bar 64 together. With the above configuration, by binding the first main reinforcement 63 and the second main reinforcement 64 together, the reinforcement 66 functions as a shear reinforcement, increasing the rigidity and strength of the reinforcement portion 61 against shear forces, and enabling it to more appropriately resist earthquake loads acting on the first support member 21 and the second support member 41.

[0080] Although one embodiment of the building of the present invention has been described above, the above embodiment is merely an example for facilitating understanding of the present invention and does not limit the present invention. In other words, the present invention can be modified and improved without departing from the spirit of the present invention. In addition, the present invention naturally includes its equivalents. [Explanation of symbols]

[0081] 1. Building 10. Foundation 10a,50a,60a,61a,62a,70a Top surface 11,12 Reinforced concrete 13,15,115 Main reinforcement 14,15 Slab reinforcement 17 Anchor bolt 20 1st floor part 21 First support member 22 Pilotis 30 2nd floor part 31,40 Load-bearing wall 41 Second support member 42 Connecting member 50,150 1st underground beam 60,160 2nd underground beam 61,118 Reinforcement 62 Beam section 63 1st main reinforcement 64 2nd main reinforcement 65 Reinforcement Bar 66 Reinforcement 67 First area 68 Second area 70 Slab section 71 Inner Slab 72 Outer Slab 110 Basics 119 Rising part D Distance

Claims

1. A multi-storey building, Support members supporting the second floor and above; A mat foundation supporting the support member from below, The slab foundation is A first underground beam extending along a first direction in the horizontal direction; A second underground beam extending along a second direction intersecting both the first direction and the vertical direction, The second underground beam has a reinforcing portion adjacent to the first underground beam in the second direction and on which the support member is placed, and a beam portion adjacent to the reinforcing portion on the opposite side of the first underground beam in the second direction with respect to the reinforcing portion, A building, wherein the thickness of the reinforcing portion is greater than the thickness of the beam portion in the vertical direction.

2. The upper surfaces of the reinforcing portion and the beam portion are at the same level in the vertical direction, The building according to claim 1 , wherein the reinforcing portion protrudes downward beyond the beam portion.

3. The slab portion of the mat foundation other than the first underground beam and the second underground beam is further provided. The building according to claim 1 , wherein the top surfaces of the first ground beam, the second ground beam, and the slab portion are at the same level in the vertical direction.

4. The mat foundation further includes a slab portion provided around the first underground beam or the second underground beam, The building according to claim 1 , wherein an outer edge of the slab portion is located outside the support member in the second direction.

5. A first floor load-bearing wall including the support member is further provided, The building according to claim 1 , wherein the reinforcing portion has a width greater than that of the load-bearing wall of the first floor in the second direction.

6. A first floor load-bearing wall including the support member is further provided, The building according to claim 1 , wherein the load-bearing wall of the first floor is located so as not to overlap with a load-bearing wall of another floor in the first direction and the second direction.

7. The second underground beam includes a first main reinforcement extending in the second direction, a second main reinforcement disposed below the first main reinforcement and extending in the second direction, and a reinforcing bar disposed between the first main reinforcement and the second main reinforcement and extending in the first direction, The building according to claim 1 , wherein the number of the steel bars arranged vertically between the first main bar and the second main bar is greater in the reinforcing portion of the second underground beam than in the beam portion.

8. The second underground beam includes a first main reinforcement extending in the second direction and a second main reinforcement disposed below the first main reinforcement and extending in the second direction, The building according to claim 1 , wherein the reinforcing portion has a reinforcing bar that connects the first main bar and the second main bar.

9. The building according to any one of claims 1 to 8, having a pilotis on the first floor.

Images