JP2014040733A - Building structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable relaxation of an increase in cross section of one column section.SOLUTION: A building structure includes a rigid-framed structure section 4 in which a beam 3 is rigidly joined throughout a pair of column sections P. A long-term axial force acting on one P1 of the pair of column sections P is set smaller than a long-term axial force acting on the other column section P2. The beam 3 is configured in such a manner that rigidity of the side of an end joined to the one column section P1 is lower than that of the side of an end joined to the other column section P2.

Description

  The present invention relates to a building structure provided with a rigid frame structure in which beams are rigidly joined across a pair of pillars.

Conventionally, as this type of building structure, a structure in which a plurality of ramen structure parts are continuous is generally used, and each column part is configured so that a load corresponding to the dominant area of the floor acts. Is known (for example, see Patent Document 1).
In such a building structure, the pillars arranged on the outer periphery of the building have a smaller floor control area compared to the pillars arranged on the center side of the building. It has become.
Further, each column portion is connected by a rigidly connected beam, and in particular, the lowermost portions of the columns are rigidly connected by a foundation beam.

JP 2006-161436 A (FIGS. 4 and 6)

Here, a ramen structure part including a pillar part (referred to as one pillar part for convenience) and a pillar part adjacent to the center of the building (referred to as the other pillar part for convenience) will be described as an example. To do.
If the column spacing is constant, the long-term axial force of the column corresponding to the floor control area is smaller in the one column with a small floor control area than in the other column with a large floor control area. The same relationship applies to the load transmitted to the foundation.
Therefore, the amount of settlement of the foundation is larger in the amount of settlement below the other column than the amount of settlement below one of the columns.
However, as shown in FIG. 2 (b), one pillar part P1 and the other pillar part P2 are rigidly joined by the beam 3 (in particular, the foundation beam 3A in the lowermost layer). Acts as a bending moment for the beam 3. In particular, a large bending moment acts on the foundation beam 3A.
As a result, since the bending moments act on both column portions P1 and P2 rigidly joined to the foundation beam 3A, one column portion is used to enhance the bending strength of one column portion P1. It is necessary to increase the cross section of P1. In particular, with respect to the one column portion having a small long-term axial force setting, the degree of increase in the cross-sectional area associated with the strengthening of the bending strength increases.
That is, particularly in the one column part, there is a problem that space restriction becomes large due to the large cross section, which may hinder the construction plan and increase the cost.

  Accordingly, an object of the present invention is to provide a building structure that can solve the above-described problems and reduce the large cross-section of one pillar.

  A first characteristic configuration of the present invention is a building structure including a ramen structure portion in which beams are rigidly connected over a pair of column portions, and the long-term structure that acts on one column portion of the pair of column portions. The axial force is set to be smaller than the long-term axial force acting on the other column portion, and the beam has a joint end portion side with the one column portion and a joint end portion with the other column portion. It is in the place where the rigidity is lower than the side.

According to the first characteristic configuration of the present invention, the beam is configured such that the joint end side with the one column part is lower in rigidity than the joint end side with the other column part. Therefore, the bending moment generated in the beam due to the difference in the amount of settlement between the two column portions is absorbed by the low-rigidity portion and hardly transmitted to one column portion.
As a result, the bending strength of one pillar part can be set low, and the enlargement of one pillar part can be eased.
Therefore, by reducing the cross section of one of the pillars, space constraints can be reduced, a highly flexible building plan can be performed, and costs can be reduced.
In addition, with regard to the increase in the burden on the other column due to the smaller cross-section of one column part, for example, by implementing a corresponding process such as increasing the cross-section of the other column or forming a seismic wall adjacent to it, Easy to deal with. In general, building cores and walls are often provided around the other pillar, which has a large long-term axial force. Easy to adopt.
Moreover, the beam rigidly joined over a pair of pillar parts is not limited to the foundation beam, and a beam in a higher hierarchy can also be a target.

  According to a second characteristic configuration of the present invention, the beam is formed such that a cross-sectional area on the joint end side with the one column portion is smaller than a cross-sectional area on the joint end side with the other column portion. The rigidity on the side of the joint end with the one column is low.

According to the second characteristic configuration of the present invention, the correlation between the cross-sectional area of the beam and the rigidity can be used, and the rigidity reduction can be designed quantitatively.
In particular, if the cross-sectional area is adjusted by changing the beam formation, the rigidity of the beam can be controlled more easily.

  According to a third characteristic configuration of the present invention, the ramen structure portion is a reinforced concrete structure, and the beam has a concrete strength on the joint end side with the one column portion and a joint end with the other column portion. It is in a place where the concrete strength on the part side is different.

According to the third characteristic configuration of the present invention, it is possible to control the beam stiffness over a wider range by increasing or decreasing the concrete strength in combination with the beam stiffness control by adjusting the cross-sectional area.
For example, if the beam cross-sectional area required to reduce the beam stiffness on one end to the target value is too small to secure the required amount of reinforcing bars, reduce the concrete strength used at the beam end. By combining the effect of lowering the rigidity due to this, it is possible to control the total beam rigidity at one end side to be the target value while suppressing the amount of reduction in the beam cross-sectional area to the extent that the required amount of reinforcing bars can be secured.
As another example, the concrete strength at one end of the beam is set higher than the concrete strength at the other end, and the beam cross-sectional area at one end is set smaller, so that the total strength at one end is reduced. It is also possible to control so that the beam rigidity becomes a target value.

  According to a fourth characteristic configuration of the present invention, the beam is a foundation beam.

  According to the fourth characteristic configuration of the present invention, the bending moment of the beam caused by the ground subsidence of the foundation appears most prominently in the foundation beam (compared to beams in other layers). It can be demonstrated most efficiently.

Sectional view showing the ramen structure Bending moment diagram of ramen structure Front view showing a building of another embodiment Sectional drawing which shows the ramen structure part of the building of another embodiment

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the parts indicated by the same reference numerals as those in the conventional example indicate the same or corresponding parts.

  FIG. 1 is a cross-sectional view showing the main parts of a base part B0 and a first floor part B1 of a building B adopting the building structure of the present invention. In addition, the display of the hierarchy above the second floor is omitted.

In this embodiment, a reinforced concrete building B will be described as an example. The building B is provided with a number of footing foundations 1 on which pillars 2 are erected. It is. The axial force from the pillar 2 acts on the footing foundation 1, and the footing foundation 1 and the pillar 2 that are continuously provided above and below are collectively referred to as a pillar portion P.
Since the footing foundation 1 is placed on the ground G, the load of the pillar portion P is supported by the ground G.

FIG. 1 shows an installation situation of a pillar part P1 located on the outer peripheral part of the building and a pillar part P2 adjacent to the inside of the building.
For the sake of convenience, in the following description, the “column part located on the outer periphery of the building” with the symbol P1 is referred to as one column part P1, and the “column part adjacent to the inside of the building” with the symbol P2. Is referred to as the other pillar portion P2.
The long-term axial force acting on the pillar portion P is set so that one pillar portion P1 is smaller than the other pillar portion P2 due to the relationship of the dominant area of the floor.
Therefore, the pillar 2a of one pillar part P1 is designed to have a lower axial strength than the pillar 2b of the other pillar part P2.

The beam 3 is rigidly joined to each adjacent column P, and the column structure P and the beam 3 constitute a frame structure portion 4.
The beam 3 shown in FIG. 1 is a foundation beam 3A.

The base beam 3A is formed with a beam smaller than the other part including the joint end part side with the other pillar part P2 on the joint end part side with the other pillar part P1. In other words, the foundation beam 3A is formed such that the cross-sectional area on the side of the joint end with the one pillar part P1 is smaller than the cross-sectional area of the other part including the joint end part side with the other pillar part P2.
Moreover, the concrete which comprises 3 A of foundation beams is used for the fixed intensity over the beam full length.
Therefore, the “part 3a with small beam formation” on the side of the joint end with one pillar P1 has lower rigidity than the “other part 3b” including the side with the joint end with the other pillar P2. Designed.

As long-term axial force acts on each pillar part P1, P2, ground subsidence occurs due to the load transmitted from each footing foundation 1 to the ground. Since the amount of settlement is estimated according to the long-term axial force acting on each column P1, P2, the other column P2 appears larger than the other column P1.
As a result, a bending moment acts on the foundation beam 3A rigidly joined to each of the pillar portions P1 and P2, as shown in FIG. Furthermore, the bending moment of the foundation beam 3A is also transmitted to the rigidly joined column portions P1 and P2.

If the building structure of the present embodiment is adopted, the bending moment of the foundation beam 3A is less with respect to the other column part P2 because the rigidity at the small beam portion 3a is lower than the other portion 3b. While being transmitted as it is, it is reduced and transmitted to one of the pillar portions P1.
This effect is as shown in the bending moment diagram of FIG. Incidentally, the bending moment diagram of FIG. 2 (b) shows a case where the rigidity of the foundation beam 3A is made constant over the entire length as a comparative example with the present embodiment.
In this way, by providing the small beam portion 3a on the joint end side with the one pillar portion P1, the bending moment generated in the foundation beam 3A is hardly transmitted to the one pillar portion P1, and the one pillar portion P1 is hardly transmitted. There is no need to make the section P1 larger than necessary.

  Incidentally, the horizontal distance of the small beam portion 3a is arbitrarily set within the range from the beam end to the beam center. In the present embodiment, a length range of ¼ of the beam length from the beam end is set as the small beam portion 3a.

[Another embodiment]
Other embodiments will be described below.

<1> The building structure is not limited to the reinforced concrete structure described in the previous embodiment, and may be any structure that can adopt a ramen structure such as a steel structure or a steel reinforced concrete structure.
<2> The method of reducing the rigidity of the beam end portion is not limited to the method of reducing the beam formation described in the previous embodiment as compared to other portions. For example, in addition to the beam formation, the beam width dimension can be increased. A method of reducing the cross-sectional area of the beam may be included.
It is also possible to adopt a method of reducing the member strength at the beam end portion from that of the other portions.
Further, a method of reducing the rigidity of the beam end portion by combining the beam cross-sectional area and the member strength may be used. In this case, it is not limited to making both the beam cross-sectional area and the member strength smaller than the other part, and there is also a method of making either one smaller than the other part while making the other larger than the other part. Is possible.
<3> One pillar part P1 and the other pillar part P2 are composed of the "pillar part located on the outer periphery of the building" and the "pillar part adjacent to the inside of the building" described in the previous embodiment. For example, any of the pillars P1 and P2 may be arranged on the inner side of the pillars located on the outer periphery of the building. In short, if there is a relationship in which the long-term axial force acting on one pillar portion P1 of the pair of pillar portions P is set smaller than the long-term axial force acting on the other adjacent pillar portion P2, it is applicable. .
As a specific example, as shown in FIG. 3, when the high layer portion H is erected in a partial range of the low layer portion L, the column portion at the boundary between the low layer portion L and the high layer portion H is Since the axial force is large, it corresponds to “the other column portion P2”, and the column portion of the lower layer portion L adjacent to it corresponds to “one column portion P1”.
<4> The beam 3 having one end formed with low rigidity is not limited to the foundation beam 3A described in the previous embodiment. For example, the beam 3 is arranged above the foundation beam 3A. May be there.
<5> The small beam portion 3a is not limited to the same beam cross-sectional shape over its entire length, and as shown in FIG. 4, the beam end portion extends from the boundary of the other portion 3b. In this case, the beam formation may be gradually reduced.

  In addition, as mentioned above, although the code | symbol was written in order to make contrast with drawing convenient, this invention is not limited to the structure of an accompanying drawing by this entry. In addition, it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention.

3 beam 3A foundation beam 4 frame structure part P pillar part P1 one pillar part P2 other pillar part

Claims (4)

A building structure having a ramen structure part in which beams are rigidly connected over a pair of pillar parts,
The long-term axial force acting on one of the pair of pillars is set to be smaller than the long-term axial force acting on the other pillar, and the beam is in contact with the one pillar. The building structure which is comprised so that rigidity may become lower than the joining edge part side with said other pillar part on the joining edge part side.   The beam is formed such that a cross-sectional area on the side of the joining end with the one pillar is smaller than a cross-sectional area on the side of the joining end with the other pillar, thereby joining the end with the one pillar. The building structure according to claim 1, wherein the structure is configured such that the rigidity on the side is low.   The ramen structure is made of reinforced concrete, and the beam has different concrete strength on the joint end side with the one column portion and concrete strength on the joint end side with the other column portion. The building structure according to claim 2.   The building structure according to claim 1, wherein the beam is a foundation beam.

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