JP7554681B2 - Earthquake-resistant walls - Google Patents

Description

The present invention relates to a seismic wall installed within the structural plane of a steel-framed column-beam structure.

Conventionally, wooden walls have been attached to steel frame members via mounting hardware (see Patent Documents 1 and 2).
In Patent Document 1, diagonal members are provided at the four corners of a wooden wall, and these diagonal members are installed diagonally between steel columns and steel beams.
In Patent Document 2, load transfer parts are provided at the four corners of the wooden wall panel, and these load transfer parts are fixed onto flanges of the steel beams.
Incidentally, the Building Standards Act stipulates that large buildings must have a fire-resistant structure in which the main structural parts, such as steel beams and steel columns, do not deform or become damaged for a certain period of time in the event of a fire. However, in the structures shown in Patent Documents 1 and 2, when a wooden wall burns in a fire, the combustion heat is transferred to the steel beams and steel columns through the mounting hardware, so there is a risk that the required fire resistance cannot be ensured.

JP 2019-218694 A JP 2020-16022 A

The present invention aims to provide a seismic wall that is installed within the structural plane of a steel-framed column-beam structure and can prevent the fire resistance of the column-beam structure from decreasing in the event of a fire.

The inventors developed the present invention based on the idea that by providing a heat absorbing section on the outer surface of the connecting metal fittings that join the wooden wall section to the column-beam structure, a part of the combustion heat generated in the wooden wall section during a fire can be absorbed by the heat absorbing section, thereby realizing a wooden earthquake-resistant wall with excellent fire resistance compared to the column-beam structure.
The earthquake-resistant wall of the first invention (for example, wooden earthquake-resistant walls 1, 1A-1G described below) is an earthquake-resistant wall provided within the structural plane of a steel-frame column-beam structure (for example, column-beam structure 2 described below), and is characterized in that it comprises a wooden wall section (for example, wooden wall section 10 described below) made of wooden boards provided within the column-beam structure, connecting metal members (for example, connecting metal members 20, 20A-20G described below) that connect the wooden wall section to the column-beam structure, and a heat absorption section (for example, mortar blocks 26, 26D described below) provided in contact with or near the connecting metal members.

According to this invention, a heat absorbing part with a large heat capacity is provided in contact with the metal joint that connects the wooden wall section and the column-beam structure. Therefore, when the wooden wall section burns due to a fire, the combustion heat is transferred to the steel-framed column-beam structure via the metal joint, and at this time, a part of the heat generated by the fire and the combustion heat of the wooden wall section is absorbed by the heat absorbing part. Therefore, by providing the heat absorbing part in contact with or near the metal joint, the amount of heat transferred to the steel-framed column-beam structure can be reduced, and the temperature rise of the column-beam structure can be suppressed. Therefore, the deterioration of the fire resistance of the steel-framed column-beam structure can be suppressed.
The heat absorbing portion is provided, for example, on the outer surface of the metal joint or on the inner surface of the metal joint.

The earthquake-resistant wall of the second invention is characterized by further comprising a closing section (e.g., closing section 30 described below) between the wooden wall section and the column-beam structure, which is closed with a cement-based material.

According to this invention, the gap between the wooden wall section and the column-beam structure is sealed with a cement-based material to form a blocking section. This blocking section acts as a joining material between the wooden wall section and the column-beam structure, enhancing the unity between the wooden wall section and the column-beam structure. In addition, since the blocking section functions as a fire-resistant coating material, when the wooden wall section burns, the combustion heat is absorbed by the blocking section in addition to the heat-absorbing material, reducing the amount of heat transferred to the steel-framed column-beam structure, and significantly suppressing the deterioration of the fire resistance of the steel-framed column-beam structure.

The third invention of the earthquake-resistant wall is characterized in that the heat absorption parts are provided on at least one of the four corners of the wooden wall section, at predetermined intervals along the surface of the wooden wall section, and on the web side of the steel beam that abuts against the metal joint.

According to this invention, the heat absorbing parts are arranged in parts of the wooden wall, i.e., at the four corners of the wooden wall or along the surface of the wooden wall, by placing metal joints at predetermined intervals. This reduces the number of attachment points for the heat absorbing parts, and makes it relatively easy to join the wooden wall to the column-beam structure.
In addition, by providing the heat absorbing part on the side of the web of the steel beam that contacts the metal joint, the amount of heat transferred to the steel-framed column-beam structure can be reduced, and the temperature rise of the column-beam structure can be suppressed. This heat absorbing part also functions as a stiffening material for the web of the steel beam.

The present invention provides a seismic wall that is installed within the structural plane of a steel-framed column-beam structure and can prevent the fire resistance of the column-beam structure from decreasing in the event of a fire.

1 is a front view of a wooden earthquake-resistant wall according to a first embodiment of the present invention; This is an enlarged view of the area surrounded by dashed line A of the wooden earthquake-resistant wall. This is an enlarged side view of a portion of a metal joint in a wooden earthquake-resistant wall. 4 is a BB cross-sectional view and a CC cross-sectional view of the metal joint of FIG. 3. 1 is a diagram for explaining the behavior of a wooden earthquake-resistant wall of the present invention when a horizontal force is applied thereto. FIG. FIG. 2 is a diagram for explaining how combustion heat is transmitted when the wooden earthquake-resistant wall of the present invention burns. FIG. 1 is a perspective view of an analytical model of a portion of a wooden earthquake-resistant wall used in a heat conduction analysis. FIG. 13 is a diagram showing the temperature change of a metal joint obtained by heat conduction analysis. FIG. 6 is a front view of the upper part of a wooden earthquake-resistant wall according to a second embodiment of the present invention. FIG. 10 is a cross-sectional view of the wooden earthquake-resistant wall shown in FIG. 9 along the line D-D. FIG. 11 is a perspective view of a metal joint for a wooden earthquake-resistant wall according to a third embodiment of the present invention. FIG. 11 is a perspective view of a metal joint for a wooden earthquake-resistant wall according to a fourth embodiment of the present invention. 13 is a side view and an E-E cross-sectional view of a metal joint for a wooden earthquake-resistant wall according to a fifth embodiment of the present invention. FIG. 13 is a diagram for explaining how combustion heat is transmitted when the wooden earthquake-resistant wall according to the fourth embodiment burns. FIG. FIG. 2 is a front view of an upper portion of a wooden earthquake-resistant wall according to a first modified example of the present invention. 13 is a perspective view of a metal joint according to a second modified example of the present invention. FIG. 13 is an oblique view of a metal joint according to a third modified example of the present invention. FIG.

The present invention relates to a wooden earthquake-resistant wall installed within the structural plane of a steel-framed column-beam structure. In this wooden earthquake-resistant wall, the wooden wall section and the column-beam structure are joined by joint metal fittings equipped with heat absorbing parts, and a sealing part is provided between the wooden wall section and the column-beam structure, which is sealed with a cement-based material.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same components are denoted by the same reference numerals, and the description thereof will be omitted or simplified.
First Embodiment
FIG. 1 is a front view of a wooden earthquake-resistant wall 1 according to a first embodiment of the present invention.
The wooden earthquake-resistant wall 1 is installed within the structural plane of a column-beam structure 2 made of steel-reinforced concrete.
The column-beam structure 2 comprises a pair of steel reinforced concrete columns 3, a pair of upper and lower steel beams 4 erected between the pair of steel reinforced concrete columns 3, and a floor slab 5 provided on top of the steel beams 4.
The wooden earthquake-resistant wall 1 comprises a rectangular wooden wall section 10 made of wooden boards provided in the horizontal center of the column-beam structure 2, joint metal fittings 20 provided at the four protruding corners of the wooden wall section 10 and joined to the steel beams 4 of the column-beam structure 2, and a closing section 30 in which the gap between the wooden wall section 10 and the steel beams 4 of the column-beam structure 2 is closed with a cement-based material. In other words, the wooden wall section 10 is joined to the column-beam structure 2 via the joint metal fittings 20 and the closing section 30.
The wooden boards constituting the wooden wall section 10 are, for example, CLT or plywood. CLT (Cross Laminated Timber) is made by laminating and gluing planks (laminae) cut from wood so that the grain direction is perpendicular to the board. Plywood is made by laminating and gluing veneers cut from wood so that the grain direction is perpendicular to the board.
The joints between the wooden earthquake-resistant walls 1 and the steel beams 4 and the steel beams 4 are covered with calcium silicate boards 6.

FIG. 2 is an enlarged view of the portion of the wooden earthquake-resistant wall 1 in FIG.
The metal joint 20 comprises a frame joint 21 which is joined to the column-beam structure 2 , and a wall joint 22 which extends vertically from the frame joint 21 and is joined to the side end face of the wooden wall section 10 .
Fig. 3 is a partially enlarged side view of the joint metal 20, Fig. 4(a) is a cross-sectional view taken along line B-B of the joint metal 20 in Fig. 3, and Fig. 4(b) is a cross-sectional view taken along line C-C of the joint metal 20 in Fig. 3. Note that in Fig. 3, the calcium silicate board 6 is omitted for ease of understanding.

The frame joint 21 is a plate-like member provided along the flange of the steel beam 4 of the column-beam frame 2 , and is joined to the flange of the steel beam 4 with a plurality of bolts 24 .
The wall joint 22 is a plate extending along the side end surface 11 of the protruding corner of the wooden wall section 10, and is joined to this side end surface 11 with a plurality of screws 25. These screws 25 are provided in multiple rows at predetermined intervals in the vertical direction.

A mortar block 26 having a large heat capacity is provided on the outer surface of the metal joint 20, i.e., at the inside corner between the frame joint 21 and the wall joint 22, as a heat absorbing portion.
In addition, the portion of the wall joint 22 of the metal joint 20 on the steel beam 4 side and the frame joint 21 are covered with a calcium silicate board 6 which functions as a fire-resistant covering material.

As shown in FIG. 3, the blocking section 30 is made by placing mesh reinforcement 32 on studs 31 welded to the steel beams 4 of the column-beam structure 2 and filling them with grout. The sides of the blocking section 30 are covered with calcium silicate boards 6.

The above wooden earthquake-resistant wall 1 operates as follows when a horizontal force acts on the column-beam structure 2. That is, since the gaps between the upper and lower end faces of the wooden wall section 10 and the steel beams 4 are closed with the blocking sections 30, a pressing force is transmitted from the steel beams 4 of the column-beam structure 2 to the wooden wall section 10 via the blocking sections 30, as shown in Fig. 5(a). The blocking sections 30 also function as a fire-resistant coating for the steel beams 4. Furthermore, as shown in Fig. 5(b), the connecting metal members 20 ensure that this horizontal force is transmitted to the protruding corners of the wooden wall section 10.
In addition, in the event of a fire, when the wooden wall section 10 burns, the heat generated by the fire and the heat of combustion of the wooden wall section 10 are transmitted to the steel beams 4 via the connecting metal fittings 20. At this time, as shown in Figure 6, part of this heat is absorbed by the mortar blocks 26 provided on the surface of the connecting metal fittings 20, reducing the amount of heat transmitted to the steel beams 4 and suppressing the rise in temperature.

[Verification of fire resistance of metal joints]
The effect of suppressing temperature rise by the heat absorbing part of the metal joint was verified below for the wooden earthquake-resistant wall of the present invention. Specifically, analysis models of the comparative example and the example were generated in a virtual three-dimensional space, and a heat conduction analysis was performed using the finite element method. Here, the comparative example had a structure in which mortar was not provided on the metal joint, and the example had a structure in which mortar was provided on the metal joint.

Fig. 7(a) is a perspective view of the analytical model as viewed from one end side, Fig. 7(b) is a perspective view of the analytical model as viewed from the other end side, and Fig. 7(c) is a perspective view of the analytical model with the calcium silicate plate removed.
As shown in FIG. 7, the analytical model this time was the portion of the wooden shear wall surrounded by the dashed line A in FIG. 1 (i.e., 1/4 of the wooden shear wall and the steel beam) and was divided in two by the central axis of the steel beam. Furthermore, the analytical model was set as follows. The steel beam was BH-400×200×12×22. The floor slab was an ALC plate with a thickness of 100 mm. The closing part was mortar with a thickness of 70 mm. The joint metal, the closing part, and the part of the side of the steel beam that is connected to the joint metal and the closing part were covered with a calcium silicate plate with a thickness of 60 mm, and the remaining part, that is, the part of the steel beam that is not connected to the joint metal and the closing part, was covered with a calcium silicate plate with a thickness of 25 mm. In other words, the side of the steel beam where the wooden shear wall is installed was covered with a calcium silicate plate with a thickness of 60 mm, and the steel beam where the wooden shear wall is not installed was covered with a calcium silicate plate with a thickness of 25 mm. However, the thermal insulation boundary surface of the steel beam end was covered with a 35 mm thick calcium silicate board. The cavity inside the steel beam was assumed to be thermally radiated only, ignoring thermal convection. Also, the wooden walls were not modeled, assuming that they would be destroyed by fire.

The analysis models of the above comparative examples and examples were heated for 2.4 hours using the standard heating temperature curve (ISO 834 curve), and the steel temperature was output. Here, the steel temperature refers to the temperature at the joint between the frame joint and the wall joint of the joint metal. Figure 8 shows the results of the heat conduction analysis (change in steel temperature over time). Figure 8 shows that providing mortar to the joint metal 20 can suppress the rise in steel temperature. Specifically, after 2 hours of heating, the temperature is approximately 460°C without mortar, but approximately 410°C with mortar, indicating that the steel temperature has been reduced by 11%.

According to this embodiment, the following effects are obtained.
(1) The mortar block 26, which is a heat absorbing part with a large heat capacity, is provided on the outer surface of the joint metal 20 that joins the wooden wall section 10 and the steel beam 4. Therefore, when the wooden wall section 10 burns due to a fire, the heat generated by the fire and the heat of combustion of the wooden wall section 10 are transferred to the steel beam 4 via the joint metal 20. At this time, a part of the heat generated by the fire and the heat of combustion of the wooden wall section 10 is absorbed by the mortar block 26, reducing the amount of heat transferred to the steel beam 4 and suppressing the rise in temperature. This makes it possible to suppress a decrease in the fire resistance of the steel-frame column-beam structure 2.

(2) The gap between the wooden wall section 10 and the steel beams 4 of the column-beam structure 2 is sealed with a cement-based material to form the blocking section 30, which acts as a joining material between the wooden wall section 10 and the steel beams 4, enhancing the unity between the wooden wall section 10 and the steel beams 4. In addition, since the blocking section 30 functions as a fire-resistant coating material, when the wooden wall section 10 burns, the combustion heat is absorbed not only by the mortar block 26 but also by the blocking section 30, reducing the amount of heat transferred to the steel beams 4, and thus significantly preventing a decrease in the fire resistance of the steel-based column-beam structure 2.

(3) Instead of placing joint metals and heat absorbing parts along the entire length of the surface of the wooden wall section 10, the joint metals 20 and mortar blocks 26 are placed only at the four corners of the wooden wall section 10. This reduces the number of attachment points for the joint metals 20, making it relatively easy to join the wooden wall section 10 and the column-beam structure 2.

Second Embodiment
Fig. 9 is a front view of the upper part of a wooden shear wall 1A according to a second embodiment of the present invention, and Fig. 10 is a cross-sectional view taken along the line DD of the wooden shear wall 1A in Fig. 9.
In this embodiment, the structure of the metal joints 20A is different from that of the first embodiment. That is, the metal joints 20A are provided at predetermined intervals along the surface of the wooden wall section 10. Specifically, three metal joints 20A are provided on each of the front side and the back side of the wooden wall section 10.
The metal joint 20A has a generally L-shaped cross section and includes a frame joint 21 that is joined to the column-beam frame 2, and a wall joint 22 that extends vertically from the frame joint 21 and is joined to the side end face of the wooden wall section 10. A mortar block 26, which is a heat absorbing part with a large heat capacity, is provided at the inside corner between the frame joint 21 and the wall joint 22. The metal joint 20A is covered with a calcium silicate board 6 that functions as a fire-resistant covering material.
According to this embodiment, there are advantages similar to those of (1) to (3) above.

Third Embodiment
FIG. 11 is a perspective view of a metal joint 20B of a wooden earthquake-resistant wall 1B according to the third embodiment of the present invention.
This embodiment differs from the first embodiment in that a rib 40 is provided at the inside corner between the frame joint 21 and the wall joint 22 of the metal joint 20B. The rib 40 is embedded in the mortar block 26.
According to this embodiment, there are advantages similar to those of (1) to (3) above.

Fourth Embodiment
FIG. 12 is a perspective view of a metal joint 20C of a wooden earthquake-resistant wall 1C according to the fourth embodiment of the present invention.
This embodiment differs from the first embodiment in that a stud bolt 41 is provided on the outer surface of the frame joint 21 of the joint metal member 20B. The stud bolt 41 is embedded in the mortar block 26.
According to this embodiment, there are advantages similar to those of (1) to (3) above.

Fifth Embodiment
Fig. 13(a) is a side view of a metal joint 20 of a wooden earthquake-resistant wall 1D according to a fifth embodiment of the present invention. Fig. 13(b) is a cross-sectional view of the wooden earthquake-resistant wall 1D of Fig. 13(a) taken along the line E-E.
This embodiment differs from the first embodiment in that the mortar block 26D is not in contact with the joint metal 20, but is provided in contact with the side of the lower flange 7 and web 8 on the joint metal 20 side of the steel beam 4.
That is, the mortar block 26D is provided between the vertical reinforcing ribs on the side of the web 8 of the steel beam 4, up to a height position midway between the lower flange 7 and the upper flange of the steel beam 4 that contacts the structural joint 21.
In this wooden earthquake-resistant wall 1D, when the wooden wall section 10 burns in the event of a fire, the heat generated by the fire and the heat of combustion of the wooden wall section 10 are transmitted to the steel beams 4 via the connecting metal fittings 20. At this time, as shown in Figure 14, part of this heat is absorbed by the mortar blocks 26D, reducing the amount of heat transmitted to the steel beams 4 and suppressing the rise in temperature.

In this embodiment, the mortar blocks 26D are provided up to a height position midway between the bottom flange 7 and the top flange of the steel beam 4, but this is not limiting, and they may be provided up to the height position of the top flange of the steel beam 4, that is, over the entire height between the bottom flange 7 and the top flange. In this way, the stiffening effect on the web of the steel beam 4 can be improved compared to when the mortar blocks 26D are provided up to a height position midway between the bottom flange 7 and the top flange of the steel beam 4.
According to this embodiment, in addition to the above-mentioned advantages (1) to (3), the following advantages are obtained.
(4) By providing the mortar block 26D in contact with the bottom flange 7 and the side surface of the web 8 of the steel beam 4, the amount of heat transferred to the steel beam 4 can be reduced, and the rise in temperature of the steel beam 4 can be suppressed. In addition, the mortar block 26D also functions as a stiffening material for the web 8 of the steel beam 4.

The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention.
In the second embodiment described above, the metal joints 20A are provided at a predetermined interval along the surface of the wooden wall section 10, but this is not limiting, and as shown in Fig. 15, metal joints 20E may be provided along the entire length of the front and back sides of the wooden wall section 10. These metal joints 20E are covered with calcium silicate boards 6 that function as fire-resistant covering materials. This also provides the same effects as (1) and (2) described above.
In addition, in each of the above-mentioned embodiments, the heat absorbing parts are provided on the outer surfaces of the joint metals 20, 20A, and 20B, but this is not limiting and they may be provided on the inner surfaces of the joint metals. Even when the heat absorbing parts are provided on the inner surfaces of the joint metals in this way, the heat absorbing parts can absorb part of the heat caused by a fire and the heat of combustion of the wooden wall section 10, thereby suppressing a decrease in the fire resistance of the column-beam structure 2.
In addition, in each of the above-described embodiments, the heat absorbing portion is formed of mortar, but the present invention is not limited to this, and the heat absorbing portion may be formed of concrete, plaster, or a heat absorbing ceramic material having excellent heat absorption properties.

In addition, in each of the fourth embodiments described above, a stud bolt 41 is provided on the outer surface of the frame joint 21 of the joint metal fitting 20B, but this is not limited to the above. Instead of the stud bolt 41, a headed stud 42 may be provided as shown in FIG. 16, or a stud bolt 43 and a nut 44 may be provided as shown in FIG. 17.

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G...Wood shear wall (shear wall)
2... Column-beam structure 3... Steel reinforced concrete column 4... Steel beam 5... Floor slab 6... Calcium silicate board 7... Bottom flange 8... Web 10... Wooden wall portion 11... Side end surface 20, 20A, 20B, 20C, 20E, 20F, 20G... metal joint 21... structural joint 22... wall joint 24... bolt 25... screw 26, 26D... mortar block (heat absorbing part)
30: Closure portion 31: Stud 32: Mesh reinforcement 40: Rib 41: Stud bolt 42: Headed stud 43: Stud bolt 44: Nut

Claims (2)

A seismic wall provided within the structural surface of a column-beam frame including a steel beam,
A wooden wall portion made of a wooden board provided in the column-beam frame;
A joint metal fitting that joins the wooden wall portion and the steel beam at a corner portion of the wooden wall portion;
A heat absorbing portion provided within the structural surface of the column-beam structure ;
A closing portion formed by closing a gap between the wooden wall portion and the steel beam with a cement-based material;
A fire-resistant covering material covering the steel beam ,
The joint metal includes a frame joint portion joined to the steel beam, and a wall joint portion extending from the frame joint portion and joined to a side end surface of the wooden wall portion,
The heat absorbing portion is in contact with the frame joint portion and the wall joint portion of the metal joint at the side of the wooden wall portion,
A seismic wall characterized in that the fire-resistant covering material covers, in addition to the steel beams, the structural joints of the metal joints, the heat absorption parts, and the closing parts . A seismic wall provided within the structural surface of a column-beam frame including a steel beam,
A wooden wall portion made of a wooden board provided in the column-beam frame;
A joint metal fitting that joins the wooden wall portion and the steel beam at a corner portion of the wooden wall portion;
A heat absorbing portion provided within the structural surface of the column-beam structure ;
A closing portion formed by closing a gap between the wooden wall portion and the steel beam with a cement-based material;
A fire-resistant covering material covering the steel beam ,
The joint metal includes a frame joint portion joined to the steel beam, and a wall joint portion extending from the frame joint portion and joined to a side end surface of the wooden wall portion,
The heat absorption portion is provided on the opposite side of the frame joint across a flange that contacts the frame joint of the steel beam,
A seismic wall characterized in that the fire-resistant covering material covers, in addition to the steel beams, the structural joints of the metal joints, the heat absorption parts, and the closing parts .

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