JP7093714B2 - Pit structure and how to build it - Google Patents

Description

The present invention relates to a pit structure, and more particularly to a pit structure in which a pit space is formed between a concrete foundation slab and a concrete floor slab on the lowest floor.

In Patent Document 1, in a pit structure in which a pit space is formed between a concrete foundation slab and a concrete floor slab on the lowest floor, the concrete foundation slab is configured as a pressure-resistant plate and is made of reinforced concrete on the pressure-resistant plate. A pit structure is disclosed in which a large number of bundle columns are supported and a concrete floor slab is supported on the numerous bundle columns.

Japanese Unexamined Patent Publication No. 2017-115499

In the pit structure of Patent Document 1, since the concrete floor slab is supported by "points" by bundle columns, the rigidity of the concrete floor slab must be increased, and the concrete floor slab has a large cross section, which is irrational. Pit structure.
In addition, since it is difficult to install steel formwork (deck plates, etc.) that does not require support on the bundle columns, many support works are installed on the pit space side when placing concrete in the concrete floor slab. It is necessary to improve the workability.

In such a pit structure, a pit structure in which a steel beam is erected between the upper part of the foundation column (the part that supports the column) and the concrete floor slab is supported on the steel beam without constructing a bundle column. Is also possible. In this way, the concrete floor slab on the lowest floor can be efficiently supported by "lines" with steel beams, so there is no need to increase the rigidity of the concrete floor slab, and the concrete floor slab is irrational. It is possible to avoid a large cross section.

However, when the distance between the upper part of the column under the foundation (column span) is relatively large, the support interval of the steel beam is inevitably large, and a large steel beam with a large beam length must be adopted. Adopting a large steel beam with a large beam will increase the cost as the amount of steel increases, and also to secure the effective pit height between the upper surface of the concrete foundation slab and the lower surface of the steel beam in the pit space. Since it is necessary to increase the height of the entire pit structure and the amount of excavation of the ground will also increase, the pit structure will also be irrational.

The present invention has been made in view of the above-mentioned circumstances, and the main problem thereof is a rational pit structure capable of avoiding a large cross section of a concrete floor slab and a large size of a steel beam and a method for constructing the pit structure. It is in the point of providing.

The first characteristic configuration of the present invention is a pit structure in which a pit space is formed between a concrete foundation slab and a concrete floor slab on the lowest floor.
The concrete foundation slab is configured as a pressure resistant plate.
Bundle columns are constructed on the pressure plate in a dispersed state,
A steel beam is erected while being supported on the bundle column,
The concrete floor slab is supported on the steel beam ,
To erection the steel beam while being supported on the bundle column,
A vertical steel plate joint plate portion is fixed on the flat upper surface of the bundle column so as to project upward along the direction in which the steel beam extends.
The steel beam is formed with a joint formed by cutting out the lower flange so that the joint plate portion and the lower flange of the steel beam do not interfere with each other.
The point where the joint plate portion and the web of the joint portion of the steel frame beam are overlapped, and the joint plate portion in the overlapped state and the web of the joint portion of the steel frame beam are joined by bolts and nuts. It is in.

According to this configuration, first of all, the concrete floor slab on the lowest floor can be efficiently supported by "lines" with steel beams, so there is no need to increase the rigidity of the concrete floor slab, and it is irrational concrete floor. It is possible to avoid a large cross section of the slab.
Nevertheless, since the steel beam is erected on the pressure plate in a state of being supported by the bundle columns constructed in a dispersed state, it is possible to shorten the support span (interval between support points) of the steel beam. It is also possible to avoid irrational enlargement of steel beams.
Therefore, it is possible to obtain a rational pit structure that can avoid a large cross section of the concrete floor slab and a large size of the steel beam.

In the second characteristic configuration of the present invention, the steel frame beam is divided into a plurality of divided steel frame beams with a portion supported on the bundle column as a boundary .
The joint is formed at each of the opposing ends of the adjacent split steel beams.
The joints of the opposing ends of the adjacent split steel beams are joined to the joint plate by bolts and nuts .

According to this configuration, it is possible to support the steel beam by the concrete bundle column, and it is possible to shorten the length of the steel beam to improve the handleability of the steel beam, and it is possible to efficiently improve the workability of the pit structure. ..

The third feature configuration of the present invention is the method for constructing the pit structure according to the first or second feature configuration.
The first step of constructing the pressure plate and the bundle pillar, and
In the second step, the steel beams are arranged side by side at intervals along the beam width direction while being supported on the bundle columns constructed in the first step.
The third step of constructing the concrete floor slab on the steel beam beam juxtaposed in the second step is provided.
In the third step, a steel formwork is erected between the steel beam adjacent to each other in the beam width direction, and concrete is placed on the steel formwork in a state where the steel formwork is not supported by the support work. It is at the point of placing.

According to this configuration, a steel formwork is erected between the steel beams supported by the bundle columns, and concrete is placed on the steel formwork without the steel formwork being supported by the support work. Since the concrete floor slab can be constructed, it is not necessary to separately install a support work in the pit space, and the pit structure can be efficiently constructed.

Side sectional view of the pit structure Explanatory drawing schematically showing the arrangement state of bundle columns and steel beams in the pit structure Side sectional view of the main part of the pit structure Side sectional view schematically showing how to construct a pit structure Side sectional view of a main part showing another embodiment of the pit structure

An embodiment of the pit structure of the present invention and a method for constructing the pit structure will be described with reference to the drawings.
As shown in FIG. 1, in this pit structure, a pit space S is formed between the concrete foundation slab 1 and the concrete floor slab 2 on the lowest floor. The pit space S is a space used for, for example, an installation space for equipment members such as equipment piping and equipment wiring, and has a minimum height at which workers can work for replacement or change of equipment members. It is configured as a space to have.

The concrete foundation slab 1 is configured as a pressure-resistant plate 1A made of reinforced concrete, and the amount of reinforcing bars, the amount of concrete (slab thickness), and the like are set so as to have rigidity capable of receiving the weight of the building. In the present embodiment, for example, a pile 3 such as a support pile is embedded below the pressure plate 1A, and the weight of the building received by the pressure plate 1A is transmitted to the support ground or the like via the pile 3.

As shown in FIGS. 1 and 2, on the outer peripheral side of the building of the pressure plate 1A, a foundation standing upper portion 4 for supporting the outer peripheral pillars of the building and the like is constructed. The upper part 4 of the foundation is made of reinforced concrete and is constructed so as to stand up from the upper surface of the pressure plate 1A. The foundation rising portion 4 is structurally connected to the pressure plate 1A by reinforcing bars and concrete, and is configured as a structure integrated with the pressure plate 1A. The foundation rising portion 4 is constructed, for example, in a continuous state along the outer peripheral portion of the building. Although not shown, the foundation standing upper part 4 can be appropriately constructed on the center side of the pressure plate 1A in order to support the internal pillars of the building.

On the center side of the pressure-resistant plate 1A, bundle columns (concrete bundle columns) 5 such as square columns made of concrete are constructed in a dispersed state. The bundle column 5 is made of reinforced concrete and is constructed so as to stand up from the upper surface of the pressure plate 1A. The bundle column 5 is structurally connected to the pressure plate 1A by reinforcing bars and concrete, and is configured as a structure integrated with the pressure plate 1A.

As shown in FIG. 2, the bundle columns 5 are arranged at the first pitch with a first interval P1 in the X direction (left-right direction in FIG. 2), and are arranged in the Y direction orthogonal to the X direction (FIG. 2). It is arranged at the second pitch with a second interval P2 in the vertical direction in the middle).
The first interval P1 in the X direction (left-right direction in FIG. 2) can be set in consideration of, for example, the beam beam of the steel frame beam 6 described later required for erection of the interval. Further, the second interval P2 in the Y direction (vertical direction in FIG. 2) can be set in consideration of, for example, the specifications of the concrete floor slab 2 and the construction method (construction method) described later.
In this embodiment, as shown in FIG. 1, the pile 3 is arranged in a portion between the adjacent bundle pillars 5 or a portion directly below the bundle pillar 5.

Then, the steel frame beam 6 is erected in a state of being supported on the bundle column 5, and the concrete floor slab 2 is supported on the steel frame beam 6. The concrete floor slab 2 is made of a reinforced concrete structure, and the amount of reinforcing bars, the amount of concrete (slab thickness), and the like are set so as to have rigidity capable of receiving a fixed load and a loaded load.

The steel beam 6 is made of, for example, an H-shaped steel (an example of a shaped steel) having flanges 6b and 6c provided above and below the web 6a in a vertical posture. The steel beam 6 has a posture extending along the X direction (horizontal direction in FIG. 2, beam length direction), and has a second interval P2 in the Y direction (vertical direction in FIG. 2, beam width direction). They are arranged side by side at two pitches. The steel beam 6 is erected over the foundation rising portion 4 and the plurality of bundle columns 5.

The steel frame beam 6 is divided into a plurality of parts in the X direction (left-right direction in FIG. 2) with a substantially central position of a portion supported on the bundle column 5 as a boundary. That is, the steel frame beam 6 is composed of a plurality of divided steel frame beams 6A divided in the X direction. Then, on the outer peripheral side of the building, the ends of the divided steel beam 6A are joined to the foundation rising portion 4 and supported by the foundation standing upper portion 4, and the opposing ends of the adjacent split steel frame beams 6A on the building center side are bundle columns. It is joined on the 5 and supported by the bundle pillar 5.

For example, on the outer peripheral side of the building, as shown in FIG. 1, a first joint plate made of a vertical steel plate protruding inward on the upper part of the flat inner side surface (the surface on the center side of the building) of the foundation rising portion 4. The portion 7 is fixed by fixing means (not shown) such as anchor bolts and nuts. The first joint plate portion 7 and the web 6a at the end of the split steel beam 6A are overlapped with each other, and the first joint plate portion 7 in the overlapped state and the web 6a at the end of the split steel beam 6A are bolted. By joining by a joining means such as a nut, the end portion of the split steel frame beam 6A and the foundation rising portion 4 are joined.
The joint form between the end of the split steel beam 6A and the foundation rising portion 4 on the outer peripheral side of the building is merely an example, and is not limited to the above configuration.

For example, on the center side of the building, as shown in FIGS. 1 and 3, the steel beam 6 projects upward along the X direction (left-right direction in FIG. 2) extending upward on the flat upper surface of the bundle column 5. The second joint plate portion 9 made of a steel plate in the posture is fixed. Of the adjacent split steel beam 6A, the end of the split steel beam 6A on one side (left side in the figure) is joined to one side (left side in the figure) of the second joint plate portion 9, and the other side (left side in the figure). The end of the divided steel beam 6A (on the right side in the figure) is joined to the other side (right side in the figure) of the second joint plate portion 9.

As shown in FIG. 3, the lower flange 6b so that the second joint plate portion 9 and the lower flange 6b of the split steel beam 6A do not interfere with each of the opposing ends of the adjacent split steel beam 6A. An end joint portion 6d formed by notching is formed. Then, the second joint plate portion 9 and the web 6a of the end joint portion 6d of the split steel beam 6A are overlapped, and the second joint plate portion 9 in the overlapped state and the end joint portion of the split steel beam 6A are overlapped. By joining the web 6a of 6d by a joining means 10 such as a bolt or a nut, the opposing ends of the adjacent split steel beams 6A are joined on the bundle column.

In the illustrated example, the opposing ends of the adjacent split steel beam 6A are separated from each other by the tip surfaces of the respective end joints 6d, and the lower surface of each end joint 6d is a bundle column. It is joined in a state of being in contact with the upper surface of 5. It should be noted that the opposing ends of the adjacent split steel beam 6A are joined in a state where the tip surfaces of the respective end joints 6d are in contact with each other, or the lower surface of each end joint 6d is a bundle column. It may be joined in a state of being separated upward from the upper surface of the above.
By the way, on the center side of the building, the joint form of the adjacent split steel beam 6A facing each other and the support form of the adjacent split steel beam 6A by the bundle columns 5 of the facing ends are just examples. , Not limited to the above configuration.

In the pit structure configured in this way, the concrete floor slab 2 on the lowest floor can be efficiently supported by the steel beam 6, so that the rigidity of the concrete floor slab 2 does not need to be increased more than necessary. , It is possible to avoid an irrational large cross section of the concrete floor slab 2.
Further, since the steel frame beam 6 is erected on the pressure plate 1A in a state of being supported by the bundle columns 5 constructed in a dispersed state, the support span (interval between the support points) of the steel frame beam 6 should be shortened. This makes it possible to avoid an irrational increase in the size of the steel beam 6.
Further, since the steel frame beam 6 is divided into a plurality of divided steel frame beams 6A with a portion supported on the bundle column 5 as a boundary, the steel frame beam 6 can be supported by the bundle column 5 while being supported by the steel frame beam 6. 6 can be shortened to improve the handleability of the steel frame beam 6.

Next, a method of constructing the pit structure configured in this way will be described.
As shown in FIG. 4, the method of constructing this pit structure includes the first step of constructing the pressure plate 1A, the bundle column 5 and the like (see FIG. 4A), and installing the steel beam 6 on the bundle column 5. The second step (see FIG. 4 (b)) and the third step of constructing the concrete floor slab 2 on the steel beam 6 (see FIGS. 4 (b) and 4 (c)) are provided. Hereinafter, each step will be described.

First, as a pre-process of the first step, excavation work for excavating the ground up to the installation surface (excavation bottom surface) of the pressure plate 1A, pile driving work for burying the pile 3 in the excavation bottom surface, and the like are performed.
After that, as the first step, reinforcement arrangement work for arranging reinforcement, formwork installation work for installing the formwork, for the planned construction points of the pressure plate 1A, the bundle pillar 5, and the foundation rising part 4 (see FIG. 1). Concrete placing work to place concrete in the formwork and formwork removal work to remove the formwork after waiting for the placed concrete to harden are performed, and as shown in FIG. 4A, the pressure-resistant plate 1A, formwork 5, and foundation stand 4 (see FIG. 1) are constructed.

After the execution of the first step, as the second step, as shown in FIG. 4 (b), the steel beam 6 is supported on the bundle column 5 and the foundation rising portion 4 (see FIG. 1) in a beam width. Steel beam installation work will be carried out in parallel with a second interval P2 (see FIG. 2) along the direction.

In the present embodiment, since the steel frame beam 6 is composed of a plurality of divided steel frame beams 6A divided into a plurality of pieces in the beam length direction, the end portion of the divided steel frame beam 6A is used as the foundation rising portion 4 on the outer peripheral side of the building. Joining work to join and support the foundation standing upper part 4 and joining work to join the facing ends of the adjacent split steel beam 6A on the bundle pillar 5 and support it to the bundle pillar 5 on the center side of the building. This is done, and a plurality of steel beam 6s arranged in the beam width direction are installed.

After the execution of the second step, as the third step, as shown in FIG. 4 (b), a deck plate 11 (an example of a steel formwork) made of a corrugated steel plate or the like between adjacent steel beam 6s in the beam width direction. Carry out construction work to install a waste formwork. As shown by the virtual line in FIG. 2, the deck plate 11 places each of the ends of the deck plate 11 in the Y direction on each of the upper surfaces of the steel frame beams 6 adjacent to each other in the beam width direction (Y direction). It can be installed in the state.

Then, a reinforcing bar 12 (see FIG. 4 (c)) such as a slab bar is arranged on the deck plate 11, and as shown in FIG. 4 (c), the deck plate 11 is pipe-supported or the like. Concrete placing work is performed in which concrete C is placed on the deck plate 11 without being supported from below. Then, the construction of the pit structure is completed after waiting for the concrete C placed on the deck plate 11 to harden.

[Another Embodiment]
Other embodiments of the present invention will be described. It should be noted that the configurations of the respective embodiments described below are not limited to being applied independently, but can also be applied in combination with the configurations of other embodiments.

(1) In the above-described embodiment, the case where the bundle column 5 is a concrete bundle column made of concrete is shown as an example, but the bundle column 5 is a steel frame column (steel frame) made of a steel frame such as a square steel pipe or a shaped steel. It may be made of a material other than concrete, such as a pillar).
When the bundle column 5 is a steel bundle column, an anchor bolt in which the leg portion of the bundle column 5 is embedded in the concrete foundation slab 1 or the base plate formed in the leg portion of the bundle column 5 is embedded in the concrete foundation slab 1 is used. By tightening with a nut, the bundle column 5 can be constructed (fixed) on the concrete foundation slab 1.

(2) In the above-described embodiment, the case where the steel frame beam 6 is divided into a plurality of parts with a portion supported on the bundle column 5 as a boundary in the beam length direction is shown as an example, but the bundle column 5 is shown. It does not have to be divided into a plurality of parts with a portion supported on the top as a boundary. In that case, as shown in FIG. 5, the intermediate portion of the steel frame beam 6 can be supported on the bundle column 5.

For example, in the example shown in FIG. 5, the lower flange 6b is cut at the middle portion of the steel beam 6 in the beam length direction so that the second joint plate portion 9 and the lower flange 6b of the steel beam 6 do not interfere with each other. An intermediate connecting portion 6e formed by lacking is formed. Then, the beam length of the steel beam 6 is formed by joining the second joint plate portion 9 and the web 6a of the intermediate connecting portion 6e of the steel beam 6 by a joining means 10 such as bolts and nuts in a state of being overlapped with each other. An intermediate portion in the direction is joined to the bundle column 5 and supported by the bundle column 5.

In the example shown in FIG. 5, the intermediate portion of the steel frame beam 6 in the beam length direction is supported by the bundle column 5 with its lower surface in contact with the upper surface of the bundle column 5. The intermediate portion of the steel frame beam 6 in the beam length direction may be supported by the bundle column 5 with its lower surface separated upward from the upper surface of the bundle column 5.
Incidentally, the support form by the bundle column 5 in the intermediate portion of the steel frame beam 6 is only an example, and is not limited to the above-mentioned configuration. For example, the intermediate portion of the steel beam 6 is simply placed on the upper surface of the bundle column 5, and in addition, the anchor bolts embedded in the upper surface of the bundle column 5 and the lower flange of the steel beam 6 are anchor bolts and nuts. It may be joined at.

1 Concrete foundation slab 1A Pressure-resistant plate 2 Concrete floor slab 5 Bundle pillar 6 Steel beam S Pit space

Claims (3)

It is a pit structure in which a pit space is formed between the concrete foundation slab and the concrete floor slab on the lowest floor.
The concrete foundation slab is configured as a pressure resistant plate.
Bundle columns are constructed on the pressure plate in a dispersed state,
A steel beam is erected while being supported on the bundle column,
The concrete floor slab is supported on the steel beam ,
To erection the steel beam while being supported on the bundle column,
A vertical steel plate joint plate portion is fixed on the flat upper surface of the bundle column so as to project upward along the direction in which the steel beam extends.
The steel beam is formed with a joint formed by cutting out the lower flange so that the joint plate portion and the lower flange of the steel beam do not interfere with each other.
A pit in which the joint plate portion and the web of the joint portion of the steel frame beam are overlapped, and the joint plate portion in the overlapped state and the web of the joint portion of the steel frame beam are joined by bolts and nuts. structure. The steel beam is divided into a plurality of divided steel beams with a portion supported on the bundle column as a boundary .
The joint is formed at each of the opposing ends of the adjacent split steel beams.
The pit structure according to claim 1, wherein the joint portions of the opposing ends of the adjacent divided steel beam are joined to the joint plate portion by the bolts and nuts . The method for constructing a pit structure according to claim 1 or 2.
The first step of constructing the pressure plate and the bundle pillar, and
In the second step, the steel beams are arranged side by side at intervals along the beam width direction while being supported on the bundle columns constructed in the first step.
The third step of constructing the concrete floor slab on the steel beam beam juxtaposed in the second step is provided.
In the third step, a steel formwork is erected between the steel beam adjacent to each other in the beam width direction, and concrete is placed on the steel formwork in a state where the steel formwork is not supported by the support work. How to build a pit structure to be placed.

Images