Building structure

Abstract

To reasonably include multistory shear walls and boundary beams, to secure a large open space on lower floors of a building and to secure a space where privacy is protected on upper floors of the building, thereby preventing the collapse of a building due to the occurrence of a large earthquake and a long-term load after the large earthquake, while improving workability, etc.SOLUTION: Provided is a building structure including left and right multistory shear walls 6 and a plurality of boundary beams 5 connecting the left and right multistory shear walls 6 for each floor. The left and right multistory shear walls 6 are joined at their distant side ends to the upper floor side of left and right outer pillars 1 extending from the lower floor to the upper floor, and joined at their adjacent side ends to left and right inner pillars 2 in which a pillar portion of the lower floor is omitted, so that they are provided over a plurality of floors on the upper floor side without including the lower floors with missing pillars. The boundary beam 5 is configured as a bending yield first type in which bending yield precedes shear failure. An axial reinforcing bar 12 extending in a material axial direction of the boundary beam 5 is provided at the upper and lower intermediate portion of the boundary beam 5 provided on the lower side of the multistory shear wall 6.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a building structure including left and right continuous multi-story seismic walls extending over a plurality of upper floors and a plurality of boundary beams connecting the left and right continuous multi-story seismic walls for each floor.

Background Art

[0002] As the background art of the present invention, for example, there is a structure including a large number of outer peripheral columns (corresponding to continuous multi-story seismic walls) arranged along the outer contour of a building and a plurality of outer peripheral beams installed between the outer peripheral columns on each floor. The outer peripheral columns are constituted by wall columns, and among the plurality of outer peripheral beams, each outer peripheral beam other than the top outer peripheral beam installed between the top outer peripheral columns is a flat beam, and a boundary beam damper is incorporated only in the top outer peripheral beam. In this way, the sway of the building during an earthquake is lengthened and reduced by the action of the flat beams on each floor, and then absorbed by a small number of boundary beam dampers incorporated in the top outer peripheral beam (see, for example, Patent Document 1).

[0003] In addition, there is a structure including left and right seismic walls continuous from the lowest floor to the uppermost floor and a plurality of RC beam dampers joining between the left and right seismic walls for each floor. Each RC beam damper includes low yield point steel bars as its main reinforcement (steel bars), and PC steel bars for prestress introduction are inserted near the center of the beam cross section in the RC beam damper. By utilizing such an RC beam damper as a boundary beam, the seismic force is reduced and the damage after an earthquake is alleviated (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a building such as a composite building where the lower floor is used for a store or the like and the upper floor side is used for an apartment building or the like, by reducing the number of columns on the lower floor, a large space suitable for a store or the like is secured on the lower floor, and a space suitable for an apartment building or the like is secured on the upper floor side. This is generally done.

[0006] As described above, in a building such as a composite building where spaces with different appropriateness are secured between the lower floor and the upper floor side, in order to improve seismic resistance, it is conceivable to provide a plurality of continuous seismic walls spanning multiple floors and a plurality of boundary beams connecting between adjacent continuous seismic walls for each floor. In this case, as the continuous seismic wall, for example, when a large number of outer peripheral columns described in Patent Document 1 or the left and right seismic walls described in Patent Document 2 are adopted, most or all of the large number of outer peripheral columns span from the lowest floor to the highest floor, and the left and right seismic walls also span from the lowest floor to the highest floor. Therefore, on the upper floor side, the presence of the continuous seismic wall makes it easier to secure a space with privacy suitable for an apartment building or the like. On the other hand, on the lower floor, the presence of the continuous seismic wall makes it difficult to secure a highly public and open large space suitable for a store or the like.

[0007] Therefore, it is conceivable to provide a continuous seismic wall that spans multiple floors without including the lower floor. In this case, when the outer peripheral beams described in Patent Document 1 are adopted as the plurality of boundary beams, since the boundary beams other than the boundary beam at the top are flat beams that are easily bent and yield, if these flat beams are bent and yield due to the occurrence of a large earthquake, due to the fact that the lower floor is in a state of column loss due to the reduction of the number of columns, the long-term load by the continuous seismic wall acts as a tensile force on each flat beam. Since this tensile force cannot be borne by the flat beam after bending and yielding, the risk of the building collapsing due to the long-term load by the continuous seismic wall after a large earthquake increases.

[0008] In addition, when adopting the RC beam dampers described in Patent Document 2 mentioned above as a plurality of boundary beams, since the RC beam dampers are reinforced by the introduction of axial force by prestress, it is possible to bear the long-term load by the continuous-story seismic wall after a major earthquake. However, since all boundary beams are made of RC beam dampers with prestress introduced, there is room for improvement in terms of improving constructability and reducing costs.

[0009] In view of this actual situation, the main problem of the present invention is to reasonably provide a continuous-story seismic wall and boundary beams, so as to ensure an open large space suitable for stores and the like in the lower floors of the building, and on the upper floor side of the building, while ensuring a space with privacy suitable for apartment houses and the like, while improving constructability and the like, prevent the building from collapsing due to the occurrence of a major earthquake or the long-term load after the occurrence of a major earthquake.

Means for Solving the Problems

[0010] The first characteristic configuration of the present invention is a building structure including left and right continuous-story seismic walls spanning multiple floors on the upper floor side and a plurality of boundary beams connecting the left and right continuous-story seismic walls for each floor, The left and right continuous-story seismic walls are joined to the upper floor side of the left and right outer columns extending from the lower floor to the upper floor at their separated ends, and their adjacent ends are joined to the left and right inner columns with the column parts of the lower floor omitted, so as to be provided over multiple floors on the upper floor side in a state not including the lower floor with column removal, The boundary beam is configured as a bending yield precedence type in which the bending yield of the main reinforcement precedes shear failure, At the upper and lower intermediate parts of the boundary beam provided on the lower side of the continuous-story seismic wall, axial reinforcement bars extending in the material axis direction of the boundary beam are provided.

[0011] According to this configuration, in the lower floor of the building, there are no left and right continuous-story seismic walls, and there are no left and right inner columns to which the adjacent side ends of the left and right continuous-story seismic walls are joined. Thus, it is possible to secure a highly public and open large space suitable for stores and the like. Also, on the upper floor side of the building, the presence of the left and right continuous-story seismic walls connected by boundary beams makes it possible to secure a space with privacy suitable for apartment houses and the like in the installation area of the continuous-story seismic walls separated by the boundary beams.

[0012] And while securing spaces with different appropriateness for the lower floor and the upper floor side in this way, when a major earthquake occurs, the main bars of each boundary beam bend and yield, so that the deformation performance (plastic deformation capacity) of the building can be ensured, and the seismic performance of the building can be improved.

[0013] Moreover, since there are no left and right continuous-story seismic walls and left and right inner columns in the lower floor, after the main bars of each boundary beam bend and yield due to the occurrence of a major earthquake, the long-term load by the continuous-story seismic walls acts as a tensile force on the lower boundary beams and as a compressive force on the upper boundary beams. At this time, the tensile force is borne by the longitudinal bars provided in the lower boundary beams, and the compressive force is borne by the concrete of the upper boundary beams. Therefore, while limiting the boundary beams provided with longitudinal bars to the minimum necessary on the lower side to improve constructability, etc., the long-term load by the continuous-story seismic walls after the occurrence of a major earthquake can be held by each boundary beam after bending and yielding.

[0014] As a result, by reasonably providing the continuous-story seismic walls and the boundary beams, while securing an open large space suitable for stores and the like in the lower floor of the building and a space with privacy suitable for apartment houses and the like on the upper floor side of the building, it is possible to prevent the building from collapsing due to the occurrence of a major earthquake or the long-term load by the continuous-story seismic walls after the occurrence of a major earthquake while improving constructability.

[0015] The second characteristic configuration of the present invention lies in that the longitudinal bars are provided so as to extend through the left and right large beams to which the left and right continuous-story seismic walls are joined and reach the left and right outer columns.

[0016] According to this configuration, since the axial reinforcement extends across the left and right outer columns, the ends of the boundary beams can be fixed to the left and right outer columns, thereby more reliably transmitting the tensile force acting on the lower boundary beam after the boundary beam bends and yields to the left and right outer columns. Also, since the fixing length of the axial reinforcement with respect to large beams and the like becomes longer, the load-bearing capacity of the axial reinforcement against the tensile force after each boundary beam bends and yields can be improved.

[0017] As a result, it is possible to more reliably prevent the building from collapsing due to the long-term load by the continuous-story seismic wall after a major earthquake occurs.

[0018] The third characteristic configuration of the present invention lies in the fact that the continuous-story seismic wall is provided on the front of the building.

[0019] According to this configuration, while preventing the building from collapsing due to the occurrence of a major earthquake or the long-term load by the continuous-story seismic wall after a major earthquake occurs, it is possible to obtain a highly designed facade without seismic slits.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

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Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0021] Hereinafter, as an example of an embodiment for carrying out the present invention, an embodiment in which the building structure according to the present invention is applied to a composite building, which is an example of a building, will be described with reference to the drawings. Furthermore, the building structure according to the present invention may be, for example, an office building, a commercial building, a hospital, a hotel, or an apartment building, etc., other than a composite building.

[0022] As shown in FIGS. 1 to 4, the composite building B exemplified in this embodiment is made of reinforced concrete and is constructed so that its front faces the road. In this composite building B, as columns, there are provided left and right outer columns 1 built from the first floor to the top floor at the left and right ends of the composite building B, and left and right inner columns 2 built from the fourth floor to the top floor at the left and right middle parts of the composite building B, etc. On the second and third floors of the composite building B, there are provided large beams 3 spanning the left and right outer columns 1, etc. On each floor above the fourth floor, there are provided left and right large beams 4 spanning the adjacent outer columns 1 and inner columns 2, and large beams 5 spanning between the adjacent inner columns 2, etc. Each of the large beams 4 and the large beams 5 is formed as a flat beam whose beam depth is smaller than the beam width.

[0023] As shown in FIGS. 1 to 2, by providing the aforementioned inner columns 2, the composite building B is in a column-free state with the number of columns reduced on each of the first to third floors which are the lower floors. As a result, on each of the lower floors, a large space LS suitable for a store, a lobby, etc. is secured, and on each of the upper floors on the upper floor side above the fourth floor, a space S suitable for an apartment building, a dormitory, etc. is secured. Furthermore, the number of lower floors where the large space LS is secured and the number of upper floors on the upper floor side where the space S is secured are not limited to the above numbers, and various changes can be made according to the type and scale of the building, etc.

[0024] In the composite building B exemplified in this embodiment, the large spaces LS1 and LS2 on the first and second floors are used for rooms for stores with a high degree of publicness, a lobby, etc., and the large space LS3 on the third floor is used for a meeting place where privacy needs to be ensured, etc. Also, on each of the upper floors on the upper floor side, the column interval in the left-right direction is set so that a wide living space Sa is secured between the adjacent outer columns 1 and inner columns 2, and a corridor space Sb is secured between the adjacent inner columns 2.

[0025] As shown in FIGS. 1 to 6, left and right continuous multi-story seismic walls 6 are provided on the front of the composite building B. As shown in FIG. 3, the left and right continuous multi-story seismic walls 6 have their separated side ends 6a joined to the upper floor sides of the left and right outer columns 1 extending from the first floor to the top floor, and their adjacent side ends 6b joined to the left and right inner columns 2 with the column parts of the lower floors (from the first floor to the third floor) omitted. Thus, they are provided to span multiple floors from the fourth floor to the top floor in a state that does not include the lower floors with missing columns.

[0026] Specifically, as shown in FIGS. 1, 3, and 5, the left and right continuous multi-story seismic walls 6 are arranged such that a plurality of seismic walls 6A joined to the outer columns 1, inner columns 2, and upper and lower large beams 4 that surround them are arranged in two left and right rows and connected from the fourth floor to the top floor. Thus, they are provided to span multiple floors from the fourth floor to the top floor in a state that does not include the lower floors with missing columns. And by forming the left and right continuous multi-story seismic walls 6 in this way, the large beams 5 spanning between the adjacent inner columns 2 on each floor above the fourth floor function as a plurality of boundary beams connecting the left and right continuous multi-story seismic walls 6 for each floor.

[0027] As shown in FIGS. 1 to 3 and 5 to 6, on the upper floor sides of the outer columns 1 to which the seismic walls 6A are joined, extending from the fourth floor to the top floor, seismic wall joining parts 1A that project forward (road side) more than the lower floor sides below the fourth floor are added. On the large beams 4 on the upper floor sides (above the fourth floor) to which the seismic walls 6A are joined, seismic wall joining parts 4A that project forward (road side) more than the large beams 3 on the lower floor sides (below the third floor) to which the seismic walls 6A are not joined are added.

[0028] As shown in FIGS. 1 to 3, at the seismic wall joint portion 1A of each outer column 1, a sleeve wall 8 is integrally formed that projects laterally outward from the seismic wall joint portion 1A and functions as a blind to block the line of sight from the road side to the verandas 7 provided on the left and right side surfaces on the upper floor side in the composite building B. As shown in FIGS. 1 to 2 and FIGS. 4 to 5, at the seismic wall joint portion 4A of each major beam 4 on the fourth floor and the left and right sleeve walls 7, a hanging wall 9 is integrally formed that functions as a blind to block the line of sight from the road side to the assembly hall on the third floor or the like. As shown in FIGS. 1 to 2, a gap G for lighting is secured between the hanging wall 9 and each major beam 3 on the third floor. As shown in FIGS. 4 to 5, the hanging wall 9 is separated from each outer column 1 in order to avoid the third floor portion of each outer column 1 becoming a short column. As shown in FIG. 1, a plurality of reinforcing bars 10 for preventing cracking are provided at the lower end portion of the hanging wall 9.

[0029] As shown in FIG. 6, a plurality of main reinforcing bars 11 extending in the material axis direction of the boundary beam are provided at both the upper and lower end portions of each boundary beam (major beam between inner columns 2) 5. Each boundary beam 5 is formed into a flat beam having a flat beam cross-section excluding the seismic wall joint portion 4A from the adjacent flat major beam 4, and by being formed into such a flat beam, it is configured as a bending yield precedence type in which the bending yield of each main reinforcing bar 11 precedes shear failure. In addition, as each boundary beam 5, instead of being formed into a flat beam, for example, it may be configured as a bending yield precedence type by limiting the number or diameter of the main reinforcing bars 11 to a minimum.

[0030] As shown in FIGS. 1 to 2 and FIGS. 5 to 6, among each boundary beam 5, a plurality of axial reinforcing bars 12 extending in the material axis direction of the boundary beam are provided in two upper and lower stages at the upper and lower intermediate portions of the boundary beam 5 provided at the fourth floor portion and the fifth floor portion, which are the lower side portions of each continuous layer seismic wall 6. Each axial reinforcing bar 12 is provided so as to pass through the left and right major beams 4 to which the left and right continuous layer seismic walls 6 are joined and extend to the left and right outer columns 1.

[0031] With the above configuration, in each floor from the 1st floor to the 3rd floor, which are the lower floors of the composite building B exemplified in this embodiment, there are no left and right continuous seismic walls 6, and there are no left and right inner columns 2 to which the adjacent side ends 6b of the left and right continuous seismic walls 6 are joined. As a result, a highly public and open large space LS suitable for stores, lobbies, etc. can be secured. Also, on each floor on the upper floor side of the 4th floor and above, the left and right continuous seismic walls 6 connected by the boundary beams 5 exist, so that a space S with privacy suitable for apartment houses, dormitories, etc. can be secured in the installation area of the continuous seismic walls 6 separated by the boundary beams 5.

[0032] And while securing spaces LS and S with different appropriateness for the lower floors and the upper floor side in this way, when a major earthquake occurs, the main reinforcement bars 11 of each boundary beam 5 bend and yield, ensuring the deformation performance (plastic deformation capacity) of the composite building B and improving the seismic performance of the composite building B.

[0033] Moreover, since there are no left and right continuous seismic walls 6 and left and right inner columns 2 on the lower floors, after the main reinforcement bars 11 of each boundary beam 5 bend and yield due to the occurrence of a major earthquake, the long-term load by the left and right continuous seismic walls 6 acts as a tensile force on the lower boundary beams 5 and as a compressive force on the upper boundary beams 5. At this time, the tensile force is borne by the longitudinal reinforcement bars 12 provided in the lower boundary beams 5, and the compressive force is borne by the concrete of the upper boundary beams 5. Therefore, while limiting the boundary beams 5 provided with the longitudinal reinforcement bars 12 to the minimum necessary on the lower side (the 4th floor part and the 5th floor part) to improve constructability, etc., the long-term load by the left and right continuous seismic walls 6 after the occurrence of a major earthquake can be held by each boundary beam 6 after bending and yielding.

[0034] As a result, by reasonably providing the continuous seismic walls 6 and the boundary beams 5, an open large space LS suitable for stores, lobbies, etc. is secured on the lower floor of the composite building B, and a space S with privacy suitable for apartment houses, dormitories, etc. is secured on the upper floor side of the composite building B. While improving constructability, etc., it is possible to prevent the composite building B from collapsing due to the occurrence of a major earthquake or the long-term load by the left and right continuous seismic walls 6 after the occurrence of a major earthquake.

[0035] Furthermore, by having the longitudinal reinforcing bars 12 provided in each boundary beam 5 on the lower side extend across the left and right outer columns 1, the ends of each boundary beam 5 can be fixed to the left and right outer columns 1. As a result, for example, compared to the case where the longitudinal reinforcing bars 12 are joined to the main reinforcing bars (not shown) of the large beam 4 adjacent to the boundary beam 5 on the lower side by a lap joint, after the boundary beam 5 bends and yields, the tensile force acting on the boundary beam 5 on the lower side can be more reliably transmitted to the left and right outer columns 1. Also, by increasing the fixing length of the longitudinal reinforcing bars 12 with respect to the large beam 4 adjacent to the boundary beam 5 on the lower side, etc., the load-bearing capacity of the longitudinal reinforcing bars 12 against the tensile force after each boundary beam 5 bends and yields can be improved.

[0036] As a result, it is possible to more reliably prevent the composite building B from collapsing due to the long-term load by the left and right continuous-story seismic walls 6 after a major earthquake occurs.

[0037] And by providing the left and right continuous-story seismic walls 6 on the front of the composite building B, while preventing the composite building B from collapsing due to the long-term load by the left and right continuous-story seismic walls 6 after a major earthquake occurs, a facade with high design quality without seismic slits can be obtained.

[0038] Moreover, since the left and right continuous-story seismic walls 6 are integrally formed with the left and right sleeve walls 8 and the drop walls 9 that block the line of sight from the road side to the left and right verandas 7 and the third-floor assembly hall, etc., a facade with even higher design quality can be obtained.

[0039] Note that the number of stages of the boundary beam 5 provided with the longitudinal reinforcing bars 12, and the number of longitudinal reinforcing bars 12 and the number of stages in each boundary beam 5, etc., can be variously changed according to the tensile force by the left and right continuous-story seismic walls 6 acting on the boundary beam 5 on the lower side after the boundary beam 5 bends and yields.

[0040] 〔Alternative Embodiment〕 An alternative embodiment of the present invention will be described. Note that the configurations of the respective alternative embodiments described below are not limited to being applied independently, and can also be applied in combination with the configurations of the above-described embodiment and other alternative embodiments.

[0041] (1) In the above embodiment, as the composite building (structure) B, an example was given of one having a set of continuous-story seismic wall structures composed of left and right continuous-story seismic walls 6 and a plurality of boundary beams 5 connecting them on each floor. However, the present invention is not limited to this. For example, two or more sets of continuous-story seismic wall structures may be provided side by side on the left and right. In this case, for example, it is conceivable to join the continuous-story seismic walls 6 of the continuous-story seismic wall structures located on the left and right to the outer columns 1 provided between adjacent continuous-story seismic wall structures.

[0042] (2) In the above embodiment, as the left and right continuous-story seismic walls 6, an example was given of those in which the left and right sleeve walls 8 and the hanging walls 9 are integrally formed. However, the present invention is not limited to this. For example, either one of the left and right sleeve walls 8 and the hanging walls 9 may be integrally formed, or the left and right sleeve walls 8 and the hanging walls 9 may not be integrally formed.

[0043] (3) In the above embodiment, as the axial reinforcement 12 of the boundary beam 5, an example was given of one that extends from the left and right large beams 4 to which the left and right continuous-story seismic walls 6 are joined to the left and right outer columns 1. However, the present invention is not limited to this. For example, it may be joined to the main reinforcement (not shown) of the large beam 4 adjacent to the boundary beam 5 by a lap joint.

Explanation of Reference Numerals

[0044] 1 Outer column 2 Inner column 3 Large beam 5 Boundary beam 6 Continuous-story seismic wall 6a Isolated-side end 6b Adjacent-side end 11 Main reinforcement 12 Axial reinforcement B Building

Claims

1. A building structure comprising left and right continuous multi-story seismic walls spanning multiple floors on the upper floor side, and a plurality of boundary beams connecting the left and right continuous multi-story seismic walls for each floor, wherein the left and right continuous multi-story seismic walls have their separated side ends joined to the upper floor sides of the left and right outer columns extending from the lower floor to the upper floor, and their adjacent side ends joined to the left and right inner columns with the column portions of the lower floor omitted, so as to span multiple floors on the upper floor side in a state not including the lower floor with column removal, the boundary beams are configured as a flexural yielding precedence type in which the flexural yielding of the main reinforcement precedes shear failure, and a building structure in which axial reinforcement bars extending in the material axis direction of the boundary beam are provided at the upper and lower middle portions of the boundary beam provided on the lower side of the continuous multi-story seismic wall.

2. The building structure according to claim 1, wherein the axial reinforcement bars are provided so as to extend through the left and right large beams to which the left and right continuous multi-story seismic walls are joined and over the left and right outer columns.

3. The building structure according to claim 1 or 2, wherein the continuous multi-story seismic wall is provided on the front of the building.

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