JP7051597B2 - Truss beam - Google Patents

Description

The present disclosure relates to truss beams having a high deformation capacity during an earthquake.

The truss beam is composed of individual lumbers and slanted lumbers, and is a member that resists the axial force generated in each member in the elastic region. Generally, the chords are straight or curved, and the slanted lumber is straight. There are many.

The deformation ability of the steel frame member is mainly evaluated by the structural characteristic coefficient (hereinafter referred to as "Ds value") determined by the width-thickness ratio of the individual material. The Ds value is applied to a single filling material member such as H-shaped steel. The larger the deformation performance, the smaller the Ds value, and the smaller the seismic force for design. However, it cannot be applied to the width-thickness ratio of the individual material of the truss beam, and there is no member type of the truss beam itself. It is customary. Therefore, when installing truss beams, it is necessary to design with a large seismic force (large Ds value) as a "building" with poor deformation performance, including not only truss beams but also other columns and beams. It was an uneconomical design.

In Non-Patent Document 1, in a flat truss member incorporated in a rigid frame frame, a buckling restraining member or a member having stable history characteristics is replaced with a buckling restraining member, so that the entire truss frame has a stable history. It is stated that it is possible to design to give characteristics, and it will be possible to handle the frame in the same way as the filling material (H-shaped steel, etc.) without considering the influence of buckling of individual materials.

The lower chord material may have a joint portion for joining the steel material such as H-shaped steel protruding from the pillar and the steel material such as H-shaped steel constituting the main body of the lower chord material to each other. Patent Document 1 describes a vibration damping structure using this joint. This vibration damping structure has a friction damper, and the friction damper is interposed between a pair of auxiliary plates that sandwich the steel material protruding from the pillar and the main body of the lower chord material, and a pair of auxiliary plates and the steel material protruding from the pillar. It has a friction plate and a sliding plate, and the steel material, the auxiliary plate, the friction plate and the sliding plate protruding from the pillar are fastened so as to be in pressure contact with each other. When relative slip occurs between the friction plate and the sliding plate, energy during an earthquake is absorbed and buckling is suppressed.

Japanese Unexamined Patent Publication No. 2006-183324

Architectural Institute of Japan, "Guidelines for Buckling Design of Steel Structures", Architectural Institute of Japan, November 2009

However, the vibration damping structure having the friction damper described in Patent Document 1 has a complicated structure and is difficult to handle at the construction site.

In view of such problems, it is an object of the present invention to provide a truss beam having a buckling prevention structure that can be easily attached to a joint portion and capable of handling a frame in the same manner as a filling material. ..

The truss beam according to at least some embodiments of the present invention has an upper chord member (2), a lower chord member (3) and a plurality of diagonal members (4), and is supported by a pair of structural members (5, 5). The truss beam (1, 1, 23) was formed, and the lower chord member was a second lower chord member (7) and one end thereof was joined to one end portion of the first lower chord member. It has a lower chord member (8), and the joint portion (9,22,24,31,41,51,81) between the first lower chord member and the second lower chord member has a flat plate shape, and one of the main members is formed. A steel surrender joint plate (10, 33,43,53) and plate-shaped restraining members (12,34,44,54) arranged at an angle with respect to the yielding joint plate in order to suppress buckling of the yielding joint plate. It is characterized by having. Here, "to make an angle" with respect to the yield joint plate means that the main surface of the yield joint plate and the main surface of the restraint plate are not parallel to each other.

According to this configuration, since the yield joint plate functions as a buckling prevention member, that is, a member in which buckling is prevented and plastic deformation is possible, the frame can be handled in the same manner as the filling material. Further, since the buckling prevention member has a simple structure of a yield joint plate, its installation is relatively easy.

The truss beam according to at least some embodiments of the present invention is characterized in that, in the above configuration, the restraining member (12, 62) is insulated from the yielding joint plate (10).

According to this configuration, the restraint plate prevents buckling of the yield joint plate, but the influence on the plastic deformation of the yield joint plate can be reduced.

In the truss beam according to at least some embodiments of the present invention, in the above configuration, the first lower chord member and the second lower chord member are each made of H-shaped steel, and the yield joint plate is the first lower chord member. The first restraining member (7a, 7a), which is in contact with the material and the web (7b, 8b) of the second lower chord material, has both ends fixed to a pair of flanges (7a, 7a) of the first lower chord material. It is characterized by having 12a) and a second restraining member (12b) whose both ends are fixed to a pair of flanges (8a, 8a) of the second lower chord member.

According to this configuration, buckling of the yield joint plate can be prevented with a simple configuration.

In the truss beam according to at least some embodiments of the present invention, in the above configuration, the extension direction of the restraint member (34, 44, 54) is the extension of the yield joint plate (33, 43, 53). Consistent with the direction, the restraining member is characterized by being coupled to the yielding joint plate. For example, the yield joint plate and the restraint plate are the flange (33) and the web (34) of the CT section steel (32), and one flange (43) and the web (44) of the H section steel (42), respectively. Alternatively, it can be configured by a web (53) and a flange (54) of channel steel (52).

According to this configuration, since the yield joint plate and the restraint plate are composed of an integral member, mounting is easy.

In any of the above configurations, the truss beam according to at least some embodiments of the present invention has a third lower chord member (82) in which the lower chord member is arranged between the first lower chord member and the second lower chord member. ), And the intermediate portion of the yielding joint plate is in contact with the third lower chord member.

According to this configuration, the lower chord material can be separated at a plurality of places in one joint.

According to the present invention, it is possible to provide a truss beam having a buckling prevention structure that can be easily attached to a joint portion and capable of handling a frame like a filling material.

Front view of the truss beam according to the first embodiment II-II sectional view in FIG. Front view of the truss beam according to the second embodiment Front view of the truss beam according to the third embodiment The figure which shows the 1st modification of the lower chord material joint part (A: front view, B: BB sectional view in FIG. 4A) Sectional drawing which shows the 2nd deformation example of the lower chord material joint part Sectional drawing which shows the 3rd deformation example of the lower chord material joint part The figure which shows the 4th modification of the lower chord material joint part (A: perspective view which omitted the 2nd lower chord material, B: perspective view) Front view showing the fifth deformation example of the lower chord material joint

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show the truss beam 1 according to the first embodiment. The truss beam 1 has an upper chord member 2, a lower chord member 3, and a plurality of diagonal members 4, and both ends thereof are supported by a pair of columns 5 and 5. The truss beam 1 may have a bundle member (not shown). Since the truss beam 1 has a substantially mirror image symmetrical shape, one of both ends in the extending direction will be described as an example, but the other end also has the same configuration.

The upper chord member 2 and the lower chord member 3 are arranged substantially parallel to each other along the horizontal direction. The upper chord member 2 and the lower chord member 3 of the first embodiment are linear members, but may be curved members. Both ends of the upper chord member 2 and the lower chord member 3 are rigidly joined or pin-joined to the corresponding column 5, respectively.

As the plurality of diagonal members 4 are arranged from one end side to the other end side in the extending direction of the truss beam 1, those directed diagonally downward and those directed diagonally upward are alternately arranged. When indicating a plurality of diagonal members 4 arranged at specific positions, the first diagonal member 4a, the second diagonal member 4b, and the third diagonal member 4a, the second diagonal member 4b, and the third diagonal member 4a are arranged in this order from the one arranged on the side of the pillar 5 toward the center. It is described as diagonal material 4c, and when it indicates an unspecified item or the whole, it is simply described as diagonal material 4. Each diagonal member 4 is made of a long steel member such as an H-section steel or a pair of channel steels arranged in parallel with each other. The angles of the diagonal members 4 with respect to the upper chord member 2 and the lower chord member 3 are substantially equal to each other. The upper end of the first diagonal member 4a is rigidly joined or pin-joined to the upper chord member 2 and the column 5 via the gusset plate 6. In two diagonal members 4 and 4 whose upper end sides are adjacent to each other, such as the second diagonal member 4b and the third diagonal member 4c, the upper end sides thereof are rigidly or pin-bonded to each other via a common gusset plate 6. At the same time, it is rigidly or pin-bonded to the upper chord member 2. Further, in two diagonal members 4 and 4 whose lower end sides are adjacent to each other such as the first diagonal member 4a and the second diagonal member 4b, these lower end sides are rigidly joined or pinned to each other via a common gusset plate 6. It is joined and rigidly joined or pin-joined to the lower chord member 3. The upper chord member 2, the lower chord member 3 and the diagonal member 4 are fastened to the gusset plate 6 with bolts, nuts (not shown) or the like.

The lower chord member 3 is a second lower chord member whose end is joined to the first lower chord member 7 protruding from the pillar 5 and the protruding end portion of the first lower chord member 7 to form an intermediate portion in the extending direction of the lower chord member 3. It has a material 8 and. Although H-shaped steel is used for the first lower chord material 7 and the second lower chord material 8, long steel materials such as other shaped steels and steel pipes may be used. In the H-shaped steel constituting the first lower chord member 7, a pair of flanges 7a and 7a face each other in the vertical direction, and the web 7b is arranged along the vertical plane. Similarly, in the H-section steel constituting the second lower chord member 8, a pair of flanges 8a and 8a face each other in the vertical direction, and the web 8b is arranged along the vertical plane. Since the lower chord member joint portion 9 of the first lower chord member 7 and the second lower chord member 8 functions as a buckling restraining member, it should be provided in a portion where buckling is likely to occur, that is, near the end portion of the lower chord member in the extending direction. Is preferable, and in the first embodiment, it is located below the first diagonal member 4a.

The lower chord member joint portion 9 is arranged so as to straddle between the first lower chord member 7 and the second lower chord member 8, and a pair of steel having both ends fixed to the first lower chord member 7 and the second lower chord member 8, respectively. It has the surrender joint plates 10 and 10. The pair of yield joint plates 10 and 10 each have a rectangular flat plate shape, and the lower chord member 3 has one main surface in contact with the web 7b of the first lower chord member 7 and the web 8b of the second lower chord member, respectively. It extends in the extension direction. The pair of yield joint plates 10 and 10 abut on the web 7b of the first lower chord member 7 and the web 8b of the second lower chord member 8 from opposite sides to each other. Both ends of the pair of yield joint plates 10 and 10 in the extending direction are fixed to the web 7b of the first lower chord member 7 and the web 8b of the second lower chord member 8 by fasteners 11 such as bolts and nuts. The intermediate portion of the pair of yield joint plates 10 and 10 in the extending direction is in contact with the web 7b of the first lower chord member 7 and the web 8b of the second lower chord member 8, but is not fixed. The shape of the pair of yield joint plates 10 and 10 may be such that the intermediate portion is constricted with respect to both ends fastened by the fastener 11 and the width in the vertical direction is narrowed (see FIG. 4). ..

Further, the lower chord member joint portion 9 has a restraining member 12 arranged at an angle with the yield joint plate 10 in order to suppress buckling of the yield joint plate 10. It is preferable that the restraining member 12 has a flat plate shape and its main surface is arranged so as to be orthogonal to the extending direction of the yield joint plate 10. A plurality of restraining members 12 are arranged on both sides of the webs 7b and 8b at predetermined intervals in the extending direction of the yield joint plate 10. The restraining member 12 has a plurality of first restraining members 12a attached to the first lower chord member 7 and a plurality of second restraining members 12b attached to the second lower chord member 8. The upper end and the lower end of the first restraining member 12a are fixed to the facing surfaces of the pair of flanges 7a and 7a of the first lower chord member 7 by welding or fastening with bolts and nuts, respectively. One side edge of the first restraining member 12a is insulated from the yielding joint plate 10 by being in contact with or separated from the surrender joint plate 10 without being fixed. The other side edge of the first restraining member 12a is preferably aligned with the outer edge of the pair of flanges 7a, 7a of the first lower chord member 7 in the vertical direction, or is located inward of the outer edge. Similarly, the upper end and the lower end of the second restraining member 12b are fixed to the facing surfaces of the pair of flanges 8a and 8a of the second lower chord member 8 by welding or fastening with bolts and nuts, respectively. One side edge of the second restraining member 12b is insulated from the yielding joint plate 10 by being in contact with or separated from the surrender joint plate 10 without being fixed. The other side edge of the second restraining member 12b is preferably aligned vertically with the outer edge of the pair of flanges 8a, 8a of the second lower chord member 8 or located inward thereof. Therefore, the yielding joint plate 10 is inserted into the gap between the webs 7b and 8b and the restraining member 12. The restraining member 12 may be fixed to a portion of the webs 7b and 8b where the yielding joint plate 10 does not abut by welding or fastening with bolts and nuts.

The upper chord member 2 is a second upper chord that is joined to a first upper chord member 13 projecting from a pillar 5 and an end portion thereof to a protruding end portion of the first upper chord member 13 to form an intermediate portion in the extending direction of the upper chord member 2. It has a material 14. Although H-shaped steel is used for the first upper chord member 13 and the second upper chord member 14, long steel materials such as other shaped steels and steel pipes may be used. The upper chord member joint portion 15 between the first upper chord member 13 and the second upper chord member 14 is located above the first diagonal member 4a. In the upper chord member joint portion 15, both ends of the joint plate 16 arranged so as to straddle the first upper chord member 13 and the second upper chord member 14 are fixed to the first upper chord member 13 and the second upper chord member 14 with fasteners 11. Consists of. The length of the yield joint plate 10 in the extending direction is longer than the length of the joint plate 16 in the extending direction, which is not expected to be plastically deformed, so as to have a sufficient plastic region length.

When a compressive force acts on the yield joint plate 10 during an earthquake, the buckling of the yield joint plate 10 is significantly reduced by the restraint of the restraint member 12, and the energy of the earthquake is absorbed by the plastic deformation of the yield joint plate 10. In this way, the lower chord material joint 9 functions as a buckling restraining member, so that it is possible to design the truss frame as a whole to give stable history characteristics, and it is possible to design the truss frame without considering the influence of individual buckling. Similarly, it becomes possible to handle the frame of the truss beam 1. Further, since the buckling can be restrained by the simple configuration of the yielding joint plate 10 and the restraining member 12, it is easy to attach the buckling. Further, since the restraint member 12 is insulated from the yield joint plate 10, the restraint member 12 prevents the buckling of the yield joint plate 10, but the influence on the plastic deformation of the yield joint plate 10 is small, and an earthquake occurs. The plastic deformation of the lower chord member 3 at time can be surely caused by the yield joint plate 10 instead of the main body portion composed of the first lower chord member 7 and the second lower chord member 8.

3 and 4 show the truss beam 21 according to the second embodiment and the truss beam 26 according to the third embodiment, respectively. In the description, the configurations common to the first embodiment are omitted from the description and the same reference numerals are given, and in the configurations which are partially different but have many common points, only the different portions are described and the same reference numerals are given.

In the truss beam 21 according to the second embodiment, the lower chord lumber joint 22 is located below the first lumber 4a and the second lumber 4b, which is common with the first embodiment, but the first lumber 4a and the truss beam 21 It differs from the first embodiment in that the second diagonal member 4b is joined to the first lower chord member 7.

In the truss beam 23 according to the third embodiment, the lower chord member joint portion 24 is located below the second diagonal member 4b and the third diagonal member 4c, and is from the joint portion between the lower end of the diagonal member 4 and the lower chord member 3. It differs from the first and second embodiments in that it is arranged in a staggered manner. Further, the first lower chord member 7 is joined to the second lower chord member 8 at one end side, but the other end side is not the pillar 5, but the joint plate 16 is attached to the protruding end of the lower chord member 25 protruding from the pillar 5. It is joined through. As shown in the truss beams 1, 1, 2 and 23 according to the first to third embodiments, the position where the lower chord member 3 is separated into the first lower chord member 7 and the second lower chord member 8 can be arbitrarily set. ..

Further, the yielding joint plate 10 in the third embodiment has a shape in which the intermediate portion is constricted as compared with both end portions fastened to the lower chord member 3 when viewed from the front. The yielding joint plate 10 may be rectangular in front view as in the first and second embodiments.

5 to 7 show first to third modifications of the first to third embodiments, respectively.

In the first modification shown in FIG. 5, in the lower chord member joint portion 31, a pair of CT shaped steels 32 are attached to the webs 7b, 8b of the first and second lower chord members 7, 8 from opposite sides to each other. .. The CT section steel 32 has a flat plate-shaped flange 33 and a web 34 whose side edges are fixed to the center in the width direction of the flange 33 and extend in the same direction as the flange 33, and is T-shaped in cross-sectional view. Make. The main surface of the flange 33 of each CT shaped steel 32 on the side where the web 34 is not connected abuts on the webs 7b and 8b of the first and second lower chord members 7, 8 and the flange 33 of the CT shaped steel 32 extends. Both ends in the existing direction are fastened to the webs 7b and 8b of the first and second lower chord members 7, 8 by fasteners 11, respectively. The flange 33 of the CT shaped steel 32 functions as a yield joint plate, and the web 34 of the CT shaped steel 32 functions as a restraining member. Since the flange 33, which is a yield joint plate, and the web 34, which is a restraining member, are made of an integral member, mounting is easy.

In the second modification shown in FIG. 6, in the lower chord member joint 41, a pair of H-shaped steels 42 are attached to the webs 7b, 8b of the first and second lower chord members 7, 8 from opposite sides to each other. .. The main surface of one flange 43 of each H-shaped steel 42 on the side where the web 44 is not connected abuts on the webs 7b and 8b of the first and second lower chord members 7, 8 and the extending direction of the flange 43. Both ends are fastened to the webs 7b and 8b of the first and second lower chord members 7, 8 by fasteners 11, respectively. One flange 43 of the H-shaped steel 42 serves as a yield joint plate, and the web 44 of the H-shaped steel 42 functions as a restraining member. Since one of the flanges 43, which is the yield joint plate, and the web 44, which is the restraining member, are made of an integral member, it is easy to install.

In the third modification shown in FIG. 7, in the lower chord member joint 51, a pair of channel steels 52 are attached to the webs 7b, 8b of the first and second lower chord members 7, 8 from opposite sides to each other. .. The channel steel 52 has a flat plate-shaped web 53 and a pair of flanges 54, 54 extending from both side edges of the web 53 to the same side so as to be orthogonal to the web 53. The main surface of each channel steel 52 on the web 53 opposite to the extending side of the pair of flanges 54, 54 abuts on the webs 7b, 8b of the first and second lower chord members 7, 8 and the web. Both ends of the 53 in the extending direction are fastened to the webs 7b and 8b of the first and second lower chord members 7 and 8 by fasteners 11, respectively. The web 53 of the channel steel 52 functions as a yield joint plate, and the pair of flanges 54, 54 of the channel steel 52 functions as a restraining member. Since the pair of flanges 54, which are the web 53 restraint members, which are the yield joint plates, are made of an integral member, they are easy to install.

FIG. 8 shows a fourth modification of the first to third embodiments.

In the lower chord member joint portion 61 according to the fourth modification, one end of the yield joint plate 10 is fixed in the vicinity of the end portion of the first lower chord member 7 on the second lower chord member 8 side, and all the restraining members 62. Is fixed to the second lower chord member 8. Even if one end of the yield joint plate 10 is fixed in the vicinity of the end of the second lower chord member 8 on the first lower chord member 7 side and all the restraining members 62 are fixed to the first lower chord member 7. good.

In the lower chord material joint portion 61 according to the fourth modification, each restraining member 62 is made of a CT-shaped steel web having a T shape in a cross-sectional view, and the lower chord material joint portion 61 has a plurality of pairs of restraining members 62. Have. The CT section steel having the flange and the web which is the restraining member 62 is arranged so that each surface is parallel in the vertical direction and the flange abuts on the web 8b of the lower chord member 3 made of the H section steel. The pair of CT-shaped steel flanges are fixed to the portion of the web 8b of the lower chord member 3 where the yield joint plate 10 is not in contact with fasteners such as bolts and nuts. The flange of the CT shaped steel may be fixed to the flange 8a instead of the fastener by other means such as welding, or may be fixed to the flange 8a instead of the web 8b or together with the web 8b. Further, the web (restraint member 62) of the CT shaped steel may be fixed to the lower chord member 3 in place of the flange of the CT shaped steel or together with the flange.

FIG. 9 shows a fifth modification of the first to third embodiments. The lower chord member joint portion 81 according to the fifth modification is between the first lower chord member 7 to which one end side of the yield joint plate 10 is fixed and the second lower chord member 8 to which the other end side of the yield joint plate 10 is fixed. The third lower chord member 82 is arranged, and the restraining member 12 is fixed to the third lower chord member. A part of the restraining member 12 may be provided on the first lower chord member 7 and / or the second lower chord member 8. In this way, the yield joint plate 10 may be arranged so as to straddle the portions of the lower chord member 3 that are divided at two or more points. Further, horizontal ribs 83 for reinforcement are provided at both ends of the yield joint plate 10 as needed.

Although the description of the specific embodiment is completed above, the present invention can be widely modified without being limited to the above embodiment. The truss beam may be supported by a structural member of the building other than the pillar, for example, a beam or the like. The H-section steels used for the lower and upper chords may be arranged with a weak shaft, i.e., with a pair of flanges extending vertically and the web extending horizontally. The configurations of each embodiment and each modification may be combined as long as they do not contradict each other.

1,1,23: Truss beam 2: Upper chord material 3: Lower chord material 4: Diagonal material 5: Pillar (structural member)
7: 1st lower chord material 7a: Flange 7b: Web 8: 2nd lower chord material 8a: Flange 8b: Web 9, 22, 31, 41, 51, 61, 81: Lower chord material joint (joint)
10: Yield joint plate 12, 62: Restraint member 32: CT section steel 33: Flange (yield joint plate)
34: Web (restraint member)
42: H-section steel 43: One flange (yield joint plate)
44: Web (restraint member)
52: Channel steel 53: Web (yield joint plate)
54: Flange (restraint member)

Claims (2)

A truss beam having an upper chord lumber, a lower chord lumber and a plurality of diagonal lumbers and supported by a pair of structural members.
The lower chord material has a first lower chord material and a second lower chord material.
The joint between the first lower chord material and the second lower chord material is
It has a flat plate shape, and one main surface extends in the extending direction of the lower chord material so as to abut against the first lower chord material and the second lower chord material, and both ends thereof are the first lower chord material and the first lower chord material, respectively. 2 Steel yield joint plate fixed to the lower chord material,
It has a plate-shaped restraining member arranged at an angle with respect to the yielding joint plate in order to suppress buckling of the yielding joint plate.
The restraint member is insulated from the yield joint plate and is insulated from the yield joint plate.
The first lower chord material and the second lower chord material are each made of H-shaped steel.
The yielding joint plate abuts on the web of the first lower chord material and the second lower chord material, and is brought into contact with the web.
The restraining member includes a first restraining member whose both ends are fixed to a pair of flanges of the first lower chord member, and a second restraining member whose both ends are fixed to a pair of flanges of the second lower chord member. A truss beam characterized by having . The lower chord material further includes a third lower chord material arranged between the first lower chord material and the second lower chord material.
The truss beam according to claim 1 , wherein the intermediate portion of the yielding joint plate is in contact with the third lower chord member.

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