JP6731255B2 - Building structure - Google Patents

Description

The present invention relates to a building structure built on a narrow site, having a narrow frontage, a large depth, and a vertically elongated building shape.

In the Tokyo metropolitan area, in order to secure a large floor area, there is a building structure called a pencil building in which the ratio of the building height to the length of the building in the short side direction (hereinafter referred to as the tower ratio) is large. Many have been built.

In a building structure with a large tower ratio, when an earthquake load is applied, horizontal displacement is often large at the top of the building, and there is a risk of contact with adjacent buildings, and a large overturning moment is generated at the foot of the building. To do.
Therefore, for buildings with a tower ratio of more than 4, it is necessary to confirm the structural safety by taking measures to prevent the foundation from rising and preventing the building from falling based on the current Building Standards Law and technical standards. .. Conventionally, in a building having a tower ratio of more than 4, a pile foundation structure is adopted, or a damping building structure in which a damping member is arranged on the middle floor of the building is adopted. However, the pile foundation structure and the damping building structure often have restrictions on the building plan, and there is a problem that the construction cost increases.
Further, as related techniques, basic structure techniques shown in Patent Documents 1 to 3 are known.

Patent Document 1 discloses a shock absorbing mechanism for a building as shown in FIG. FIG. 8A is a plan view showing a part of the foundation, and FIG. 8B is a sectional view taken along line HH′ of FIG. 8A. In this building, the foundation 102 is directly supported by the wrapping concrete 101 on the support ground 104. Between these, the impact absorbing member 103 is installed by fixing one end 103a directly to the foundation 102 and the other end 103b to the lap concrete 101. A buckling prevention member 104 is installed so as to cover the shock absorbing member 103.
When a horizontal force is applied to the building due to an earthquake, the foundation 102 directly floats up from the lap concrete 101. The intermediate portion 103c of the shock absorbing member 103 is plastically deformed by the tensile force associated with this lifting, and is deformed by the compressive force at the time of restoration, so that the shock at the time of restoration is moderated.
In addition, the foundation structure of Patent Document 1 is provided with an impact mitigation mechanism that allows the intermediate portion 103c of the impact mitigation member 103 to be plastically deformed and the foundation 102 to be lifted directly from the laple concrete 101 when an earthquake load is applied. The point is a feature. However, in a building with a large tower ratio, it is not possible to resist the large overturning moment generated in the building legs. Further, as shown in FIG. 8A, the impact mitigation member 103 is directly installed on the entire outer peripheral portion of the foundation 102, which causes a problem that the construction cost increases.
Further, the shock absorbing member is embedded in wrinkle concrete (non-reinforced concrete), and reinforcing bars and the like are not arranged around the shock absorbing member. Therefore, the impact-dampening member embedded in the unreinforced concrete body cannot be said to have sufficient fixing performance, and there is a risk that the impact-dampening member will come out when the foundation is directly lifted.

Patent Document 2 discloses a rebuilding method for a new building as shown in FIG. In the rebuilding method, first, an existing underground structure is partially dismantled, and the underground outer wall 112 and the underground floor 113 which will be the filler filling portion 111 are left. Next, the filling material 114 is filled in the filling material filling section 111 to construct the foundation ground 115. After that, a step of constructing the foundation 117 of the new building 116, which at least partially protrudes outside the outer edge portion of the underground outer wall 112, is included on the foundation ground 115.
In the basic structure of Patent Document 2, the basic ground 115 and the basic part 117 of the new building 116 built on the basic ground 115 are not particularly joined, and there is a risk of falling in the new building 116 having a large tower ratio.

Patent Document 3 discloses a foundation structure 120 in which a ground improvement body 124 is installed below a direct foundation 123 as shown in FIG. 10. In the foundation structure 120 of Patent Document 3, the direct foundation 123 that supports the upper structure 121 is widened and installed, and the ground improvement body 124 of the cement mixing and stirring system is installed up to the support layer in the ground, and the direct foundation 123 and Bonded reinforcing bars 125 are arranged between the ground improvement bodies 124. However, the installation range of the ground improvement body 124 and the effective arrangement method of the joint reinforcing bars 125 are not disclosed and are unknown.

JP, 2008-133597, A JP, 2015-34436, A JP-A-2002-81081

Based on the above-mentioned problems, the present invention is high in a new building with a large tower ratio, not by a pile control structure or a damping building structure in which damping members are installed, but by a simple foundation structure type. An object is to provide a building structure in which structural safety is ensured.

The present invention adopts the following means in order to solve the above problems. That is, the building structure according to the present invention is a building structure in which a vertical reinforced concrete member is joined to the lower surface of the foundation slab of the new building in a new building having a tower ratio of more than 4, and a plane of the new building. A first pull-out resistance bar is arranged at a predetermined interval between both ends of the base slab and the vertical reinforced concrete member along the longitudinal direction in the visual sense.
Here, "tower ratio" means the ratio of the building height to the length in the lateral direction in plan view, and "tower ratio exceeds 4" means that the tower ratio is rounded off. It means that it is 4 or more.
According to this structure, the vertical reinforced concrete members are joined to both end portions of the lower surface of the foundation slab in the longitudinal direction of the building through the first pull-out resistance bar, so that when a seismic load is applied to the new building. When one end of the foundation slab tries to float up, the vertical reinforced concrete member joined to the foundation slab resists, and at the other end of the foundation slab, a pushing force is generated due to a couple action. Is offset by the bearing pressure resistance of the vertical reinforced concrete members, ensuring high structural safety. Therefore, it is possible to resist the overturning moment of the building leg portion when an earthquake occurs with a robust structure.
In addition, in a building structure with a large tower ratio, the overturning moment that occurs in the building legs in the building lateral direction is larger than the building longitudinal direction, so in the present invention, both ends of the foundation slab lower surface along the longitudinal direction of the new building are By joining the portion and the vertical reinforced concrete member by the first pull-out resistance bar, the vertical reinforced concrete member functions as a pull-out resistance pile force for preventing overturning. The foundation slab and the vertical reinforced concrete member are joined by the first pull-out resistance bar arranged in the vertical direction, and can be easily constructed with a simple structure. In addition, as shown in FIG. 5, both ends of the first pull-out resistance bar are respectively laid in the basic slab in which concrete axial reinforcements and reinforcing bars are reinforced and in the vertical reinforced concrete member. Even if one end of the foundation slab is about to float, the first pull-out resistance bar is embedded in the reinforced concrete, and the first pull-out resistance bar can be prevented from coming out.
In addition, the connection by the first pull-out resistance bar is limited to the joint positions that are rational for the pull-out resistance at both ends along the longitudinal direction of the new building, reducing the man-hours required to install the first pull-out resistance bar. However, the steel material cost and the construction cost can be reduced.

In one aspect of the present invention, the building structure is characterized in that a base floor of a new building or an existing building is joined to a lower surface of the vertical reinforced concrete member.
According to this structure, since the foundation bottom plate is joined to the vertical reinforced concrete member, the structural safety against lifting of the foundation is improved and the falling moment generated in the building leg is more effectively resisted. it can. In addition, the foundation floor that is joined to the vertical reinforced concrete member can be not only a new building but also an existing building. In the rebuilding work of the building, a part of the underground structure can be reused, so the construction period can be shortened and the construction cost can be reduced. ..

In one aspect of the present invention, in the building structure, the short side length of both ends of the foundation slab is 1/3 or less of a building width in a lateral direction of a new building, and the vertical reinforced concrete member has A second pull-out resistance bar is arranged between the both ends and the base plate at a predetermined interval.
According to such a configuration, the vertical reinforced concrete member and the base of the foundation are joined via the second pull-out resistance bar, so that when the pull-out force acts on one end of the base slab, Through the pull-out resistance bar of 2, both the vertical reinforced concrete member and the foundation floor can resist the pull-out force.
In addition, by limiting the length of the short side of the foundation slab along the longitudinal direction of the new building and both ends of the vertical reinforced concrete member to 1/3 or less of the width of the new building in the lateral direction, Since the second pull-out resistance bar is limited to a rational joining position that functions as a pull-out resistance force, the steel material cost and the construction cost of the pull-out resistance bar can be reduced.

In one aspect of the present invention, the building structure, on the lower surface of the vertical reinforced concrete member, an elastic body having a rigidity lower than that of concrete forming the vertical reinforced concrete member, or a gap space, the longitudinal direction of the new building. It is characterized by being provided at predetermined intervals along the.
According to such a configuration, the elastic body or the gap space is provided in the vertical reinforced concrete member in the shape of a mountain, so that the vertical reinforced concrete member is not locally damaged even if a vertical load is applied from above. It becomes possible to carry a vertical load. Therefore, the vertical load of the building structure can be smoothly transmitted to the ground while reducing the amount of concrete forming the vertical reinforced concrete member.

According to the present invention, in a new building having a tower ratio of more than 4, by providing a basic structure in which vertical members are joined to both ends along the longitudinal direction of the basic slab constituting the basic frame, high structural safety is achieved. It is possible to realize a building structure in which

It is a vertical sectional view of a building structure of the present invention. It is a horizontal cross-sectional view of the basic structure of the building structure of FIG. It is a horizontal sectional view of (a) AA', and a horizontal sectional view of (b) BB'. It is a schematic diagram about the resistance mechanism of the basic structure part of this invention. It is a vertical cross-sectional view of the partial foundation structure in the first embodiment. FIG. 6A is an enlarged view of a vertical cross-sectional view, and FIG. 6B is an explanatory view of the partial foundation structure in the first embodiment. It is a vertical sectional view of a partial foundation frame in a 2nd embodiment. It is a vertical cross section of a partial basic frame in a 1st modification. It is explanatory drawing of the conventional impact mitigation mechanism of a building. It is explanatory drawing of the rebuilding construction method of the conventional new building. It is explanatory drawing of the basic structure of the conventional building.

The present invention, in a new building having a tower ratio of more than 4, for the purpose of preventing falls, a foundation slab and a pull-out resistance foundation body in which a vertical reinforced concrete member is joined to the lower surface of the base slab via a pull-out resistance bar. It is a building structure provided.
In the embodiment, by joining the vertical reinforced concrete members to both ends of the lower surface of the foundation slab along the longitudinal direction of the new building, one end of the foundation slab is pulled out and resistance is applied to the other end of the foundation slab. Let The long side length of both ends of the bottom surface of the foundation slab to which the vertical reinforced concrete member is joined is the building length in the building longitudinal direction, and the short side length is 1/3 or less of the building width in the building lateral direction, The position was limited to a mechanically reasonable position to prevent the fall of the building when an earthquake occurs.
Specifically, the basic structure (first embodiment) in which both ends of the bottom surface of the foundation slab are joined to the vertical reinforced concrete member via the first pull-out resistance bar, the foundation slab, the vertically reinforced concrete member, and the foundation bottom plate, In the basic structure in which the first and second pull-out resistance bars are connected (second embodiment) and the basic structure in which the basic slab, the vertical reinforced concrete member, and the base are connected, a low-rigidity elastic body is formed on the lower surface of the vertical reinforced concrete member. , Or a basic structure in which a gap space is installed (first modified example). Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
First, the technical idea and main features of the building structure of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a vertical sectional view of a building structure 1. The building structure 1 is a superstructure 3 and a foundation of the superstructure 3, and is a new building foundation 6 provided with a foundation slab 40 on the bottom surface, and directly supported by a supporting ground G located below the new building foundation 6. The basic structure 2 is provided.
The superstructure 3 of the building structure 1 has a tower ratio, that is, the ratio of the building height to the length in the short side direction in plan view exceeds 4. Here, the tower ratio of "exceeds 4" means that the tower ratio is 4 or more by rounding. That is, the building structure 1 is higher in the building height direction Z than the building width in the lateral direction X shown in FIG. 1 and has an elongated shape called a pencil building.

The direct foundation structure 2 includes a foundation bottom plate 4 and a vertical reinforced concrete member 5. FIG. 2 shows an AA′ horizontal sectional view (FIG. 2A) and a BB′ horizontal sectional view (FIG. 2B) of the basic structure of the building structure in FIG. 1. The vertical reinforced concrete member 5 is joined to the lower surface of the foundation slab 40 of the new building foundation 6. At both ends of the foundation slab 40 along the longitudinal direction Y in the plan view of the new building, as shown in FIG. 2(a), between the both ends 41 of the foundation slab 40 and the vertical reinforced concrete member 5 in the vertical direction. The first pull-out resistance muscles 10 are arranged in parallel so as to extend to. The first pullout resistance muscles 10 are arranged with a predetermined interval. As shown in FIG. 2B, the vertical reinforced concrete member 5 has the same long side length and short side length as the foundation slab 40 and the foundation bottom plate 4. Specifically, in the first pull-out resistance bar 10, as shown in FIGS. 2 and 4, the deformed bars D16 are arranged in the lateral direction X at 300 mm intervals, and also in the longitudinal direction Y at 600 mm intervals. Has been done. Further, the first pull-out resistance bars 10 are densely arranged in the lateral direction X on both sides of the foundation beam 42 as shown in FIG. The first pull-out resistance bar 10 secures a fixed length of 40 d in the base slab 40, and is embedded and fixed in the vertical reinforced concrete member 5 by about 1500 mm.
FIG. 3 shows a schematic view of the resistance mechanism of the basic structure of the present invention.
The present invention ensures that the new building is supported by the ground by arranging the new building on the bottom of the necessary and sufficient excavation depth, and the vertical reinforced concrete member 5 and the base floor 4 are joined below the foundation slab 40. It has a basic structure. The structure of the present invention prevents the building from falling by increasing the pull-out resistance against the falling moment generated in the building leg portion when an earthquake occurs.
In the building structure 1 of the present invention, in a large earthquake, a pulling force is applied to one end of the foundation slab 40 to try to float up, but one end of the foundation slab 40 passes through the first pullout resistance bar 10. Thus, the foundation slab 40, the vertical reinforced concrete member 5, and the foundation bottom plate 4 are joined, and a bearing resistance force is generated as a reaction force against the pushing force from the upper part of the building. Therefore, in the present invention, the building structure 1 having high structural safety can be provided by forming the direct foundation structure in which the vertical reinforced concrete member 5 and the foundation bottom plate 4 are joined below the foundation slab 40. Moreover, the horizontal cross-sectional shape of the vertical reinforced concrete member 5 is the same as the horizontal cross-sectional shape of the foundation slab 40, so that the pushing force from above through the foundation slab 40 makes contact with the entire bottom surface of the foundation slab 40. 5 can bear the pressure.

FIG. 4 shows a vertical cross-sectional view of the foundation skeleton in the first embodiment.
The building structure 1 according to the first embodiment is a building structure that originally existed on the site where the building structure 1 was constructed, was dismantled and removed, and then rebuilt. Below the building structure 1, the foundation frame of the building structure (existing building) before reconstruction is left as the foundation bottom plate 4. The base floor 4 is supported by the support ground G.

As shown in FIG. 2(b) and FIG. 4, the base bottom plate 4 includes a bottom wall portion 4a and outer wall portions 4b, 4c, 4d, 4e. The bottom wall portion 4a has a substantially rectangular shape having a short edge extending in the lateral direction X and a long edge extending in the longitudinal direction Y orthogonal to the lateral direction X in the horizontal plane. .. The outer wall portions 4b and 4d vertically rise from the end sides of the bottom wall portion 4a extending in the lateral direction X. Further, the outer wall portions 4c and 4e vertically rise from the end sides of the bottom wall portion 4a extending in the longitudinal direction Y. Thereby, the base bottom plate 4 is formed in a box shape.

A vertical reinforced concrete member 5 is installed on the upper surface of the base bottom plate 4. The base floor 4 is joined to the lower surface of the vertical reinforced concrete member 5. As shown in FIG. 4, the outer peripheral surface of the vertical reinforced concrete member 5 is so constructed as to be flush with the inner side surface of the building of the Yamadome wall installed along the outer wall surface of the existing structure (for example, the base floor 4). Outer wall portions 4c and 4e of the bottom plate 4 are formed. Although not shown in FIG. 4, the outer peripheral surface of the vertical reinforced concrete member 5 is also formed so that the outer wall portions 4b and 4d are flush with the outer wall portion of the foundation bottom plate 4. Specifically, the vertical reinforced concrete member 5 and the outer peripheral surface of the foundation bottom plate 4 are formed so as to be flush with each other along the inside surface of the mountain retaining wall.

As shown in FIG. 4, cage-shaped reinforcing bars 7 are arranged in the vertical reinforced concrete member 5 in the vicinity of each of the outer wall portions 4c and 4e extending in the longitudinal direction Y. FIG. 5A shows an enlarged view of a portion viewed from the arrow D in FIG. The reinforcing bar 7 includes a plurality of lateral reinforcing bars 8 and a plurality of longitudinal reinforcing bars 9. FIG. 5B is an explanatory view of the bar arrangement of the short-side reinforcing bars 8 and the long-side reinforcing bars 9. In FIG. 5A, the outer wall surface of the existing structure (for example, the outer surface 4h of the base bottom plate 4) is the building interior side surface of the mountain retaining wall as described above.

Each transverse direction reinforcing bar 8 is provided with a first outer vertical portion 8a, an intermediate horizontal portion 8b, a second outer vertical portion 8c, a lower horizontal portion 8d, an inner vertical portion 8e, and an upper horizontal portion 8f. Is a rebar formed in an annular shape by connecting the end points of in order.
Specifically, the first outer vertical portion 8a extends vertically inside the outer surface 5b of the vertical reinforced concrete member 5. The middle horizontal portion 8b is bent from the lower end of the first outer vertical portion 8a toward the inside of the vertical reinforced concrete member 5, and extends horizontally above the upper surface 4g of the outer wall portion 4e of the base bottom plate 4. The second outer vertical portion 8c is bent downward from the inner end point of the intermediate horizontal portion 8b and extends vertically inside the inner side surface 4f of the outer wall portion 4e of the base bottom plate 4. The lower horizontal portion 8d is bent inward from the lower end of the second outer vertical portion 8c toward the inside of the vertical reinforced concrete member 5 and extends horizontally above the bottom surface 4i of the foundation bottom plate 4. The inner vertical portion 8e bends upward from the inner end point of the lower horizontal portion 8d at a predetermined position from the outer wall portion 4e, and extends vertically inside the vertical reinforced concrete member 5. The upper horizontal portion 8f is bent outward from the upper end of the inner vertical portion 8e, horizontally extends inside the upper surface 5a of the vertical reinforced concrete member 5, and then connected to the upper end of the first outer vertical portion 8a. ing.

The plurality of transverse reinforcing bars 8 configured as described above are arranged in the longitudinal direction Y at intervals in the vicinity of the outer wall portion 4e of the foundation bottom plate 4. Inside each of the first outer vertical portion 8a, the intermediate horizontal portion 8b, the second outer vertical portion 8c, the lower horizontal portion 8d, the inner vertical portion 8e, and the upper horizontal portion 8f of the transverse direction reinforcing bar 8. As shown in FIG. 5B, a plurality of longitudinal reinforcing bars 9 extending in the longitudinal direction Y are arranged.

As shown in FIG. 4, in the vicinity of the outer wall portion 4c on the side opposite to the outer wall portion 4e, a reinforcing bar 7 formed symmetrically to the shape described above with respect to the outer wall portion 4e is arranged in the same manner as the outer wall portion 4e. It is set up. With such a configuration, the vertical reinforced concrete member 5 includes two outer vertical reinforced concrete members 5h, which are located near the outer wall portions 4c and 4e extending in the longitudinal direction Y and in which the reinforcing bars 7 are embedded. An inner vertical concrete member 5g, which is sandwiched between two outer vertical reinforced concrete members 5h and has no reinforcing bars embedded therein, is provided. In each figure, the boundary between the outer vertical reinforced concrete member 5h and the inner vertical concrete member 5g is shown as a boundary line E. In this embodiment, the outer vertical reinforced concrete member 5h and the inner vertical concrete member 5g are integrally formed.

As shown in FIG. 4, a new building foundation 6 is installed above the vertical reinforced concrete member 5. The new building foundation 6 and the foundation slab 40 that serves as the bottom plate of the new building foundation 6 have a rectangular shape in plan view that is approximately the same size as the bottom wall portion 4 a of the foundation bottom plate 4. A vertical reinforced concrete member is joined to the lower surface of the foundation slab 40 of the new building foundation 6. Specifically, both ends 41 of the foundation slab 40 along the longitudinal direction Y in the plan view of the new building and the vertically reinforced concrete member 5 extending vertically below the new building foundation 6 extend between them. It is joined by the existing first pull-out resistance bar 10. The first pullout resistance bars 10 are installed at both ends 41 of the base slab 40 with a predetermined space.
The first pull-out resistance bars 10 are arranged between the boundary line E, that is, on the outer vertical reinforced concrete member 5h from a position above the upper surface 4g of the foundation bottom plate 4 and in the vicinity of the outer side surface 5b of the vertical reinforced concrete member 5. Several are installed. Each of the first pull-out resistance bars 10 is installed so as to extend in the vertical direction, the lower end 10a thereof is buried in the vertical reinforced concrete member 5, and the upper end 10b thereof is buried in the foundation slab 40 of the new building foundation 6. ..

By providing the above configuration, the vertical reinforced concrete member 5 is formed in a rectangular parallelepiped shape, and when the vertical reinforced concrete member 5 is divided by the boundary line E which is a vertical plane, the outer vertical reinforced concrete member 5h is also a rectangular parallelepiped. It is in a state. That is, the outer vertical reinforced concrete member 5h is provided in a rectangular parallelepiped shape along the outer peripheral portion of the base slab 40 extending in the longitudinal direction Y. The vertical reinforced concrete member 5 and the foundation slab 40 are joined by the first pull-out resistance bar 10 in the outer vertical reinforced concrete member 5h. Thereby, the new building foundation 6 is integrated with the rectangular parallelepiped outer vertical reinforced concrete member 5h along the outer peripheral portion extending in the longitudinal direction Y, and is supported thereby.

As shown in FIG. 1, a superstructure 3 is installed on a new building foundation 6. In the present embodiment, the width of the new building foundation 6 in the lateral direction X is slightly narrower than the width of the vertical reinforced concrete member 5 in order to avoid the existing mountain retaining piles near the site boundary line. The width of the superstructure 3 in the lateral direction X is the same as that of the new building foundation 6 in the vicinity of the ground GL, which is the lowermost end, but gradually increases as the height direction Z increases to a certain height Z1. The height is equal to or larger than the width of the vertically reinforced concrete member 5 at the height of Z1 or more. As a result, below the new building foundation 6, concrete is filled between both ends of the building structure 1 that are located on opposite sides in the lateral direction X, and the vertical reinforced concrete member 5 is formed. ing.

The building structure 1 as described above is constructed as follows. First, the existing building structure is dismantled, and the foundation base 4 is left and removed. Next, as shown in FIG. 4, the reinforcing bars 7 and the first pull-out resistance bars 10 are arranged on the foundation bottom plate 4, and the entire reinforcing bars 7 and the lower end 10a of the first pull-out resistance bars 10 are embedded. Then, concrete is placed above the foundation bottom plate 4 to form the vertical reinforced concrete member 5. Further, the new building foundation 6 is installed so that the upper end 10b of the first pullout resistance bar 10 is buried with the foundation slab 40, and the superstructure 3 is constructed on the new building foundation 6.

Next, operations and effects of the building structure 1 shown as the above embodiment will be described.

In the building structure 1 described above, the vertical reinforced concrete member 5 is joined to the both ends 41 of the lower surface of the foundation slab 40 in the building longitudinal direction Y through the first pull-out resistance bar 10, so that an earthquake occurs in the new building. When one end of the foundation slab 40 tries to float when a load is applied, the vertical reinforced concrete member 5 joined to the foundation slab 40 resists, and the other end of the foundation slab 40 is subjected to a couple action. Although a pushing force is generated, the pushing force is canceled by the bearing resistance of the vertical reinforced concrete member 5, so that high structural safety is ensured. Therefore, it is possible to resist the overturning moment of the building legs caused by an earthquake with a robust structure.
In addition, in the building structure 1 having a large tower shape ratio, since the overturning moment that occurs in the building leg portion in the building lateral direction X is larger than the building longitudinal direction Y, the lower surface of the foundation slab 40 along the longitudinal direction Y of the new building is By joining the both end portions 41 and the vertical reinforced concrete member 5 by the first pull-out resistance bar 10, the vertical reinforced concrete member 5 functions as a pull-out resistance pile force for preventing overturning. The foundation slab 40 and the vertical reinforced concrete member 5 are joined by the first pull-out resistance bar 10 arranged in the vertical direction, and can be easily constructed with a simple structure. Further, as shown in FIG. 5, both ends of the first pull-out resistance bar 10 are laid out in the basic slab 40 and the vertical reinforced concrete member 5 in which the axial direction reinforcing bar and the reinforcing bar are arranged in concrete, respectively. By doing so, even if one end of the base slab 40 tries to float up, the first pull-out resistance bar 10 is buried in the reinforced concrete, and the first pull-out resistance bar 10 can be prevented from coming out.
Further, the joining by the first pull-out resistance bar 10 is limited to both ends along the longitudinal direction Y of the new building, which are rational joining positions for pull-out resistance, and is required for the installation of the first pull-out resistance bar 10. The man-hours can be reduced and the steel material cost and construction cost can be reduced.

In addition, in the building structure 1 described above, since the base pedestal 4 is joined to the vertical reinforced concrete member 5, structural safety with respect to lifting of the foundation is enhanced, and with respect to the falling moment generated in the building legs, It can resist more effectively. Further, the foundation bottom plate 4 joined to the vertical reinforced concrete member 5 may be not only a new building but also an existing building. In the rebuilding work of the building, part of the underground structure can be reused, which shortens the construction period and reduces the construction cost. It can be reduced.

Further, the outer wall portions 4b, 4c, 4d, 4e of the foundation bottom plate 4 act as mountain retaining walls at the time of removing the building structure before rebuilding, so that the construction is easy. Thereby, the construction cost can be further reduced.

[Second Embodiment]
Next, with reference to FIG. 6, a second embodiment of the direct foundation structure 2 of the building structure 1 shown as the above embodiment will be described. FIG. 6 is an explanatory diagram of the direct substructure 20 according to the second embodiment. The direct foundation structure 20 according to the second embodiment is different from the direct foundation structure 2 of the building structure 1 described above in that it includes the outer vertical reinforced concrete members 5h that are both ends of the vertical reinforced concrete member 5 and the foundation of the building structure before rebuilding. It differs from the bottom plate 4 in that the second pull-out resistance streaks 21 extending between them are arranged at a predetermined interval so that they are joined to each other.

More specifically, a space is provided in the longitudinal direction Y so as to extend in the vertical direction between each of the bottom wall portion 4a and the outer wall portions 4c, 4e of the foundation bottom plate 4 and the outer vertical reinforced concrete member 5h. The second pull-out resistance bar 21 is installed. As shown in FIG. 2, in the second pull-out resistance bar, the deformed rebars D16 are arranged at 300 mm intervals in the lateral direction X and at 600 mm intervals in the longitudinal direction Y, as in the first pull-out resistance bar. ing.
In addition, in the short side length of the both end portions 41 along the longitudinal direction Y of the base slab 40, that is, the width a in the lateral direction X and the building width b in the lateral direction X of the new building shown in FIG. The width a is less than 1/3 of the building width b.

In the above building structure, when the vertical reinforced concrete member 5 and the foundation bottom plate 4 are joined via the second pull-out resistance bar 21, when a pulling force acts on one end of the base slab 40, Both the vertical reinforced concrete member 5 and the foundation floor 4 can resist the pull-out force via the first and second pull-out resistance bars 10 and 21.
In addition, the base side slab 40 along the longitudinal direction Y of the new building and the short side length a of both ends of the vertical reinforced concrete member 5 are symmetric with respect to the central position in the lateral direction X of the new building as shown in FIG. As a result, by limiting the width to 1/3 or less of the building width b in the lateral direction X of the new building, the first and second pull-out resistance bars 10 and 21 are limited to rational joint positions that function as pull-out resistance. Therefore, the steel material cost and the construction cost of the pullout resistance bars 10 and 21 can be reduced.

As with the first embodiment, the second embodiment can reduce the steel material cost and the construction cost by which it is possible to resist the falling moment of the building leg portion that occurs when an earthquake occurs with a robust structure. It goes without saying that the effects such as reduction can be obtained.

(First Modification of Embodiment)
Next, a first modification example of the direct foundation structure 2 of the building structure 1 shown as the first and second embodiments will be described with reference to FIG. 7. FIG. 7: is explanatory drawing of the direct foundation structure 30 in a 1st modification. The direct foundation structure 30 in the first modified example is different from the direct foundation structure 2 described above in that a recess is formed in the lower surface of the vertical reinforced concrete member 31.

More specifically, the vertical reinforced concrete member 31 in the direct foundation structure 30 includes a recess formed by the inner wall 31a on the lower surface of the inner vertical concrete member 31g.
The cross-sectional shape of the concave portion in the lateral direction X is formed in a mountain shape, more preferably, a catenary curve is formed. Further, the concave portions are provided at predetermined intervals along the longitudinal direction Y so as to have a mountain shape having the same cross-sectional shape at any position in the longitudinal direction Y orthogonal to the lateral direction X in the horizontal plane. Has been. The recesses are formed so that both lower ends 31b of the recesses, which are in contact with the bottom surface 4i of the base bottom plate 4, are located near the boundary line E. The recess is preferably filled with an elastic body 32 or the like having a rigidity lower than that of concrete forming the vertical reinforced concrete member 31, but may be a gap space 32 without being filled with anything. The low-rigidity elastic body may be a foam, embankment, concrete dismantling debris, or the like that can form a mountain shape.

According to such a configuration, since the elastic body or the gap space 32 is provided in the vertical reinforced concrete member 31 in a mountain shape, the vertical reinforced concrete member 31 is locally damaged even when a vertical load is applied from above. It is possible to carry a vertical load without doing so. Therefore, the vertical load of the building structure can be smoothly transmitted to the ground while reducing the amount of concrete forming the vertical reinforced concrete member 31.

As in the case of the first embodiment, the first modified example can resist the overturning moment of the building leg that occurs when an earthquake occurs with a robust structure. It goes without saying that the effects such as reduction can be obtained.

(Other modifications of the embodiment)
It should be noted that the building structure of the present invention is not limited to the above-described first and second embodiments and modified examples described with reference to the drawings, and other various modified examples are within the technical scope thereof. Conceivable.
For example, in the above-described embodiment and modified example, the building structure is a rebuilt building structure, and under the building structure, the foundation frame of the building structure before reconstruction is left as a foundation floor plate. However, the present invention is not limited to this, and the building structure may be a newly-built building structure, and the foundation bottom plate may be provided when a new building is constructed.

Further, in the above-described embodiment and modification, the outer vertical reinforced concrete member 5h and the inner vertical concrete member 5g are integrally formed, but joints may be provided between them to be formed separately.

Moreover, in the said embodiment and modification, although the outer peripheral surface of the new building foundation 6 was formed so that it might become flush with the outer peripheral surface of a vertical reinforced concrete member, as shown in FIGS. The width may be smaller than that of the new building foundation, and the new building foundation may be formed so as to cover the outer wall (rise) of the vertical reinforced concrete member.
Further, in the above-described embodiment, the vertical reinforced concrete member is approximately equal to the horizontal cross-sectional shape of the foundation slab, but the first pull-out resistance bar is arranged along the longitudinal direction of the building where the lifting force and pushing force are concentrated. It may be only the both end portions having a certain unit width. Further, the vertical reinforced concrete member may have only the both end portions and the central portion may be a reinforced concrete structure.

Other than this, the configurations described in the above-described embodiments and modifications can be selected or changed to other configurations without departing from the gist of the present invention.

1 Building structure 20 Direct foundation structure 2 Direct foundation structure 21 Second pull-out resistance bar 3 Upper structure 30 Direct foundation structure 4 Foundation floor 31 Vertical reinforced concrete member 5 Vertical reinforced concrete member 32 Elastic body or gap space 6 New building foundation 40 Basic slab 7 Reinforcing Bar 41 Both Ends of Foundation Slab 8 Short-side Reinforcing Bar X Short-side Direction 9 Longitudinal Reinforcing Bar Y Long-side 10 First pull-out resistance bar

Claims (4)

A building structure in which a vertical reinforced concrete member is joined to the lower surface of the foundation slab of the new building in a new building with a tower ratio exceeding 4,
The vertical reinforced concrete member is provided to extend downward in contact with the entire lower surface of the foundation slab,
And both end portions of the foundation slab of the person direction orthogonal to the longitudinal direction in the plan view of the new building, the between the vertical reinforced concrete member, the longitudinal direction the first pullout resistance muscles of the plurality at predetermined intervals A building structure characterized by being reinforced. A building structure in which a vertical reinforced concrete member is joined to the lower surface of the foundation slab of the new building in a new building with a tower ratio exceeding 4,
Between the both ends of the foundation slab and the vertical reinforced concrete member along the longitudinal direction in a plan view of the new building, the first pull-out resistance bar is arranged at a predetermined interval,
Wherein the lower surface of the vertical reinforced concrete members, new building or buildings structures wherein the existing building foundation bottom plate are joined. The short side length of both ends of the foundation slab is 1/3 or less of the width of the new building in the lateral direction,
The building structure according to claim 2, wherein second pull-out resistance bars are arranged at predetermined intervals between both ends of the vertical reinforced concrete member and the foundation bottom plate. On the lower surface of the vertical reinforced concrete member, an elastic body having a rigidity lower than that of concrete forming the vertical reinforced concrete member, or a gap space is provided along the longitudinal direction of the new building at predetermined intervals. The building structure according to any one of claims 1 to 3, which is characterized.

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