JP7744280B2 - Buildings and their construction methods - Google Patents

Description

The present invention relates to buildings, particularly to steel-framed reinforced concrete buildings that include some reinforced concrete construction, and to methods for constructing such buildings.

Steel-reinforced concrete (SRC) buildings have the advantage of being able to reduce the number of columns and create spacious interior spaces, making them suitable for large commercial facilities. In SRC buildings, the ends of the built-in steel frames of the beams (girders) that span between the columns are usually rigidly connected to the built-in steel frames of the columns.

Patent Document 1 describes the framework of an SRC building constructed of steel (S) construction, in which the built-in steel frames of some beams are pin-joined to the built-in reinforcing bars of the columns.

JP 2006-37530 A

However, to achieve a rigid connection, it is usually necessary to sandwich a diaphragm between the column's built-in steel frame and secure it by welding, and then weld the flange part of the beam's built-in steel frame to the side of the diaphragm, which is a time-consuming process. Also, if the beams to be joined to the column are different sizes, individual diaphragms must be installed, but this is not desirable as it would increase the beam size to accommodate larger beams. While it is possible to increase the size of the beam's built-in steel frame to reduce the amount of work required, this is not desirable as it would increase the size of the joint between the column and beam.

In light of the above, the present invention aims to provide a building and a construction method that eliminates the need for excessively large beams and simplifies construction work.

The building of the present invention is a steel-framed reinforced concrete building that includes some reinforced concrete construction, and is characterized in that, in at least some of the beams among a plurality of beams erected between adjacent columns, the built-in steel frame of the beams is fixed at its ends with bolts to gusset plates fixed to the built-in steel frame of the columns, and is embedded in the beams with concrete.

In the building of this invention, the built-in steel frames of some beams are fixed with bolts to gusset plates fixed to the built-in steel frames of the columns, and are then embedded in concrete in this state, making it possible to construct steel-reinforced concrete (SRC) beams with simple construction work. Note that the flanges of the built-in steel frames of the beams that are fixed to the built-in steel frames of the columns via gusset plates are not rigidly connected to the columns.

In addition, the built-in steel frame of the beam, which is fixed to the built-in steel frame of the column via a gusset plate, does not bear the bending stress from the column, which broadens the size options and makes it possible to reduce the size of the joint between the column and beam.

In this way, in the building of the present invention, the built-in steel frame of the beam, which is fixed to the built-in steel frame of the column via the gusset plate, can be considered not to exist in the structural calculations of the building.

Furthermore, in the building of the present invention, it is preferable that the built-in steel frame of the beam, which is fixed to the built-in steel frame of the column via the gusset plate, has a bending strength sufficient to support the built-in steel frame of the column before the concrete hardens.

In this case, it is possible to stabilize the temporary structure, which consists of steel frames built into the columns and beams, before the concrete hardens.

Furthermore, it is preferable that the beam containing the built-in steel frame, which is fixed to the built-in steel frame of the column via the gusset plate, has a shorter beam span than the other beams.

In this case, the bending moment acting on the beam containing the built-in steel frame, which is fixed to the built-in steel frame of the column via a gusset plate and whose flange portion is not rigidly joined but is pin-jointed, is reduced, making it possible to reduce the cross-sectional area of the beam.

The building construction method of the present invention is characterized in that at least some of the beams among multiple beams installed between adjacent columns are formed by embedding the steel frame built into the beam in concrete with bolts fastened at the ends to gusset plates fixed to the steel frame built into the columns.

The building construction method of the present invention makes it possible to obtain the same effects as the building of the present invention described above.

1 is a schematic front view illustrating the arrangement of columns and beams of a building according to an embodiment of the present invention. 1 is a schematic diagram illustrating the arrangement of columns and beams on each floor of a building according to an embodiment of the present invention. Schematic XY plane cross-sectional view showing the joint between a column and a beam with built-in steel frame pin-jointed. Schematic XZ plane cross-sectional view showing the joint between a column and a beam with built-in steel frame pin-jointed.

A building 100 according to an embodiment of the present invention will be described with reference to the drawings. Note that Figures 1 to 4 are diagrams for explaining this embodiment in a schematic manner, and the dimensions have been exaggerated.

The building 100 is a steel-reinforced concrete (SRC) structure that includes some reinforced concrete (RC) construction, and all of the columns 10 and the beams (girders) 20 connecting the columns 10 are constructed with built-in steel frames embedded in concrete together with rebar. Here, the building 100 is multi-story and square-shaped in plan view with a central space, but is not limited to this, and the number of floors and exterior shape are not specified.

Columns 10 consist of corner columns located at the four corners of building 100, perimeter columns located between the corner columns and forming the perimeter of building 100, and interior columns located between the perimeter columns and within building 100.

The beams 20 consist of an outer beam that spans between two adjacent columns 10, i.e., between a corner column and the adjacent outer column, an inner beam that spans between the outer column and the adjacent inner column, and an inner beam that spans between the inner column and the adjacent inner column.

In some beams 21 of the beams 20 (beams other than the thinly painted beams 22 in Figures 1 and 2), the steel frames built into these beams 21 are rigidly connected to the steel frames built into the columns 11. Columns 11 to which such beams 21 are connected in two directions (X-axis and Y-axis directions) have a roughly cross-shaped steel frame made of I-shaped steel beams (or H-shaped steel beams) that intersect at right angles. Although not shown, columns to which beams are connected in only one direction (X-axis or Y-axis direction) have a steel frame made of I-shaped steel beams (or H-shaped steel beams) with the longitudinal direction being the direction in which the beams are connected.

The columns 11 are then welded to diaphragms (not shown) so that they are sandwiched midway between the built-in steel frames in the vertical direction (Z-axis direction), and the flanges of the built-in steel frames of the beams 21, which are formed integrally with the diaphragms, are fixed by welding. This results in a rigid connection between the built-in steel frames of the columns 11 and the beams 21. After this rigid connection, reinforcing bars are placed and concrete is poured into the installed formwork, constructing the columns 11 and beams 21 as an integrated SRC structure. This construction can be performed using the same construction methods as conventional, and a detailed explanation will be omitted.

On the other hand, in beams 22 (thinly painted beams in Figures 1 and 2) other than beam 21 among beams 20, the built-in steel frame of beam 22 is connected to the built-in steel frame of column 12 by pin joints. Such beams 22 have a shorter beam span compared to the other beams 21. In other words, when using pin joints, columns 12 are positioned so that the beam span is shortened.

The beam 22, which is pin-jointed to the column 12 in this way, becomes an SRC structure rigidly joined to the column 12 by embedding its built-in steel frame in concrete. However, when performing structural calculations, the built-in steel frame is considered not to exist.

Below, with reference to Figures 3 and 4, an example of the structure of such a joint between a column 12 and a beam 22 will be explained.

Here, we will explain the case where the built-in steel frame 31 of column 12a is rigidly connected to the built-in steel frame 41 of beam 21a on the negative side of the Y axis, and the built-in steel frame 31 of column 12a is pin-connected to the built-in steel frame 42 of beam 22a in both the positive and negative directions of the X axis.

The built-in steel frame 31 of the column 12a is an I-shaped or H-shaped steel beam extending vertically (in the Z-axis direction), with its web extending in the Y-axis direction. On the other hand, the built-in steel frame 31 of the beam 21a is an I-shaped or H-shaped steel beam extending in the Y-axis direction, with its web extending in the Z-axis direction.

Flat steel diaphragms 51 are fixed by welding to two locations spaced apart in the Z-axis direction on the built-in steel frame 31 of column 12a. The side end faces of the built-in steel frame 41 of beam 21a are also fixed by welding to the negative Y-axis side faces of these diaphragms 51. This results in a rigid connection between the built-in steel frame 31 of column 12a and the built-in steel frame 41 of beam 21a.

Meanwhile, one end of a flat steel gusset plate 61 is welded to the positive and negative X-axis sides of the web of the built-in steel frame 31 of column 12a. The other end of this gusset plate 61 has multiple through holes (not shown). Multiple through holes (not shown) are also formed in the web at the end of the built-in steel frame 42 of beam 22a facing column 12a. Bolts (not shown) are inserted through the through holes in the gusset plate 61 and the built-in steel frame 42, respectively, and nuts (not shown) are screwed in to secure the two together, forming a pin-joint between the built-in steel frame 31 of column 12a and the built-in steel frame 42 of beam 22a.

The column 12a is provided with multiple column main reinforcements 71 extending in the Z-axis direction to surround the built-in steel frame 31 of the column 12a, and multiple shear reinforcement bars (stirrups) 72 spaced apart in the Z-axis direction to surround these column main reinforcements 71. The beam 21a is provided with multiple beam main reinforcements 73 extending in the X-axis direction to the column 12a to surround the built-in steel frame 41 of the beam 21a, and multiple shear reinforcement bars 74 spaced apart in the Y-axis direction to surround these beam main reinforcements 73. The two beams 22a extending in the Y-axis direction are provided with multiple beam main reinforcements 75 extending continuously in the Y-axis direction through the two beams 22a via the column 12a to surround the built-in steel frame 42 of the beam 22a, and multiple shear reinforcement bars 76 spaced apart in the X-axis direction to surround these beam main reinforcements 75.

In this way, a formwork (not shown) is installed with the built-in steel frames 31, 41, 42 and reinforcing bars 71-76 in place, and concrete is poured into this formwork to form the SRC columns 12a and beams 22a integrally.

In this way, when rigidly connecting the built-in steel frame of a beam, a diaphragm can be installed midway through the built-in steel frame of the column, and the flange of the built-in steel frame of the beam can be welded to this diaphragm. On the other hand, when connecting the built-in steel frame of a beam with a pin, a gusset plate can be installed on the built-in steel frame of the column.

The following describes a method for constructing a building according to an embodiment of the present invention. This construction method involves constructing an SRC structure with integrated columns and beams on each floor. The following description applies regardless of whether any floor is constructed with an SRC structure with integrated columns and beams.

First, the built-in steel frame of the column is erected. Next, the built-in steel frame of the beam is pre-assembled to the built-in steel frame of the column. At this time, the built-in steel frame 31 of the column 12a and the built-in steel frame 41 of the beam 21a are rigidly joined by welding via a diaphragm 51, and the built-in steel frame 31 of the column 12a and the built-in steel frame 42 of the beam 22a are pin-joined with bolts via a gusset plate 71. The bolts are then fully tightened.

Next, reinforcing bars such as column main reinforcement 71, beam main reinforcement 73, 75, and shear reinforcement 72, 74, 76 are placed.

Then, although not shown, formwork is installed to form the columns 12a and beams 21a and 22a.

Concrete is then poured into this formwork, constructing an SRC structure in which the column 12a and beams 21a and 22a are integrated. As a result, the built-in steel frame 42 of the pin-jointed beam 22a is embedded within the beam 22a.

As described above, according to an embodiment of the present invention, the built-in steel frame 42 of the beam 22a can be pin-joined using bolts to the gusset plate 61 fixed by welding to the built-in steel frame 31 of the column 12a.Since this built-in steel frame 42 is embedded in concrete, it is possible to construct an SRC beam 22a with simple construction work.

To rigidly connect the built-in steel frame of the column and the built-in steel frame of the beam, the built-in steel frame of the column must be cut in two places to match the height of the built-in steel frame of the beam, a diaphragm must be welded between the cut sections, and the flange part of the built-in steel frame of the beam must then be welded to the side of the diaphragm, which is a time-consuming process. If the built-in steel frame of the beam is at a different height, an additional diaphragm must be added, which is even more time-consuming.

Furthermore, since the built-in steel frame 42 of the pin-jointed beam 22a is not taken into account in structural calculations, smaller steel frames can be used, making it possible to miniaturize the joint between the column 12a and the beam 22a. However, a frame including a pin-jointed beam 22a will be structurally reinforced concrete. Furthermore, since the bending strength of the built-in steel frame 42 of the pin-jointed beam 22a is not taken into account, it is necessary to consider the size and number of the main beam reinforcement bars 75 to be placed in order to ensure the bending strength of the beam 22a.

In addition, the built-in steel frame 42 of the pin-jointed beam 22a functions as a structural member during temporary construction, stabilizing the temporary frame. The built-in steel frame 42 of the pin-jointed beam 22a acts as a structural member, just like other rebar that acts during temporary construction, and its size must be selected so that it can withstand the weight of rebar and formwork, and so that the structural member does not collapse or tilt due to the impact of pouring concrete.

Furthermore, the built-in steel frame 31 of the column 12a only needs to have a strong axis in the direction where the built-in steel frame 41 of the beam 21a is rigidly joined; the direction where the built-in steel frame 42 of the beam 22a is pin-joined does not need to be a strong axis, and an I-shaped steel frame (or H-shaped steel frame) can be used. This eliminates the need for a cross-shaped steel frame with strong axes in two directions, making it possible to simplify and lighten the structure.

Note that the present invention is not limited to the above-described embodiments and can be modified as appropriate.

10...Column, 11...Column with built-in steel frame not pinned, 12, 12a...Column with built-in steel frame pinned, 20...Beam, 21, 21a...Beam with built-in steel frame not pinned, 22, 22a...Beam with built-in steel frame pinned, 31...Built-in steel frame of column 12a, 41...Built-in steel frame of beam 21a, 42...Built-in steel frame of beam 22a, 51...Diameter beam, 61...Gassette plate, 71...Column main reinforcement, 72, 74, 76...Shear reinforcement, 73, 75...Beam main reinforcement, 100...Building.

Claims (3)

In a steel-framed reinforced concrete building that includes a portion of reinforced concrete, a joint structure is provided for joining the built-in steel frame of a beam made of I-shaped steel or H-shaped steel embedded in concrete to the built-in steel frame of a column made of I-shaped steel or H-shaped steel embedded in concrete,
A flat steel gusset plate is welded to the side of the web of the built-in steel frame of the column with one end abutting against it, and a plurality of through holes are formed in the end area on the other end side of the gusset plate,
A plurality of through holes are formed in the end region of the column side of the web of the built-in steel frame of the beam,
A joint structure between the built-in steel frame of a beam and the built-in steel frame of a column, characterized in that a through hole formed in the end region on the other edge side of the gusset plate and a through hole formed in the end region on the column side of the web of the built-in steel frame of the beam are aligned, and these built-in steel frames are pin-joined by inserting a bolt and screwing a nut to secure them . The joint structure between the built-in steel frame of a beam and the built-in steel frame of a column as described in claim 1, characterized in that the built-in steel frame of the beam erected between the built-in steel frames of two adjacent columns has a bending strength capable of supporting the built-in steel frame of the column before the concrete hardens, since both end portions are each pin-jointed via the gusset plate . 3. A joint structure between a built-in steel frame of a beam and a built-in steel frame of a column according to claim 2, characterized in that the built-in steel frame of the column is a member that does not bear load in structural calculations of the building.