JP6674288B2 - Reinforcement structure of beam-column joint - Google Patents

Description

  The present invention relates to a reinforcing structure of a beam-column joint in a building, more specifically, a connection between a column made of a steel pipe having a rectangular cross section (square steel pipe) and a beam made of a steel frame having an H-shaped cross section. The present invention relates to a reinforcement structure for a through-diaphragm type beam-column joint, which is one of the parts.

  The through-diaphragm column-beam joint includes a square joint steel pipe having an upper end face and a lower end face, and an upper diaphragm and a lower diaphragm joined to upper and lower end faces of the joint steel pipe, respectively. The upper and lower diaphragms are respectively connected to the upper and lower two rectangular steel pipes which form the pillars of the building together with the joint steel pipes, and the joint steel pipe and the upper and lower diaphragms have beams on the web and the upper and lower diaphragms, respectively. Joined at both flanges.

  In this through-diaphragm beam-column joint, when seismic force acts on the building and a bending moment is generated in the beam, the beam is transmitted to the joint steel pipe via the upper and lower diaphragms of the beam-column joint. In some cases, the axial force of the beam caused by the bending moment may cause local deformation in the joint steel pipe. Since local deformation of the joint steel pipe causes a reduction in the strength of the web of the beam joined to the joint steel pipe, a beam having a relatively large cross section is used to compensate for the decrease in the strength. However, there is a problem that the use of the beam having a large cross section causes an increase in the weight of the building and an increase in the construction cost.

  Heretofore, it has been proposed to reinforce the joint steel pipe in order to solve this problem and enable the use of a beam having a relatively small cross section. For reinforcement, a plurality of steel plate members are horizontally arranged at an interval from each other inside the joint steel pipe and welded to the inner wall surface of the joint steel pipe at the periphery of these plate members (see Patent Document 1 described later). Alternatively, it is performed by arranging a plurality of steel plate members vertically in a cross shape and welding the side edges of these plate members to the inner wall surface of the joint steel pipe (see Patent Document 2 described later).

  By the way, since the floor slab exists on the upper flange of the beam of the building, the floor slab bears a part of the axial force of the beam. For this reason, the magnitude of the axial force of the beam differs between the upper flange and the lower flange of the beam, and is greater at the lower flange. Considering this, it is conceivable that the horizontal plate member to be welded to the joint steel pipe is arranged more near the lower diaphragm of the beam-column joint. However, there is a concern that welding of these horizontal plate members to the joint steel pipe will cause a decrease in the quality of the joint steel pipe and a concomitant decrease in the performance of the joint steel pipe. On the other hand, the vertical plate member does not function sufficiently to interrupt the transmission of deformation of the joint steel pipe between the upper and lower flanges of the beam.

JP-A-2005-52247 JP-A-7-310369

  An object of the present invention is to provide a reinforcing structure that can more appropriately reinforce a steel pipe at a beam-column joint in view of the conventional technology.

  The present invention provides a steel frame having an H-shaped cross-sectional shape, comprising a square joint steel pipe having an upper end face and a lower end face, and an upper diaphragm and a lower diaphragm respectively joined to the joint steel pipe at upper and lower end faces thereof. A beam consisting of a web and upper and lower flanges, which are respectively connected to the joint steel pipe and the upper and lower diaphragms, at the lower half of the joint steel pipe. A reinforcing member disposed in the section. The one reinforcing member includes a steel flat plate portion parallel to a lower end surface of the joint steel pipe, and a steel standing plate portion extending vertically from the flat plate portion toward the lower end surface of the joint steel pipe, The flat plate portion and the upright plate portion are joined to the inner wall surface of the joint steel pipe by welding at the peripheral edge and the side edge, respectively.

  According to the present invention, the one reinforcing member disposed in the lower half of the joint steel pipe has a size caused by a bending moment generated in the beam when the building is subjected to seismic force and the beam is subjected to bending force. Of the different axial forces, the lower end of the joint steel pipe and the vicinity of the lower end of the joint steel pipe which receive transmission of a relatively large axial force particularly along the lower flange of the beam exert a reinforcing effect, and local deformation of the joint steel pipe is reduced. Contribute to suppression. Here, the reinforcement is mainly carried out by a flat plate portion constituting the one reinforcing member and parallel to a lower end surface of the joint steel pipe. On the other hand, the upright portion plays a role of reinforcing the lower end of the joint portion steel pipe and its vicinity and transmits the axial force applied to these portions to the flat plate portion, and The flat part is reinforced and its local deformation is suppressed. From this, it is possible to avoid the arrangement and welding of a plurality of other plate members similar to the flat plate portion at the lower end and in the vicinity of the lower end of the joint steel pipe and welding thereof, and the deterioration in the quality of the joint steel pipe and the deterioration in performance associated therewith. The appropriate reinforcement obtained can be realized. The one reinforcing member preferably has a maximum value of a tensile strain or a compressive strain generated in a cross section of the web of the beam when the beam is subjected to a bending force. It is arranged between the height position of the boundary and the height position where the tensile strain or the compressive strain is half of the maximum value.

The reinforcement structure further includes, in addition to the one reinforcement member, another reinforcement member disposed in an upper half portion of the joint steel pipe . The other reinforcing member includes a steel flat plate parallel to an upper end surface of the joint steel pipe, and a steel standing plate vertically extending from the flat plate toward the upper end surface of the joint steel pipe, The flat plate portion and the upright plate portion are joined to the inner wall surface of the joint steel pipe by welding at the peripheral edge and the side edge, respectively.

  The other reinforcing member performs the same reinforcing function as the one reinforcing member in the upper half part of the joint steel pipe opposite to the one reinforcing member in the lower half part of the joint steel pipe. That is, the other reinforcing member receives the relatively small axial force transmitted along the upper flange of the beam among the axial forces having different magnitudes caused by the bending moment generated in the beam during the earthquake. Exerts a reinforcing effect on the upper end of the steel pipe and its vicinity, and contributes to the suppression of local deformation of the joint steel pipe. Here, the reinforcement is mainly performed by a flat plate portion constituting the another reinforcing member and parallel to the upper end surface of the joint steel pipe. On the other hand, the upright portion serves to reinforce the upper end of the joint portion steel pipe and its vicinity and also serves to transmit the axial force applied to these portions to the flat portion, and The flat part is reinforced and its local deformation is suppressed. From this, it is possible to avoid the disposition and welding of a plurality of other plate members similar to the flat plate portion at the upper end and in the vicinity of the upper end of the joint steel pipe and the vicinity thereof, and the deterioration of the quality of the joint steel pipe and the decrease in performance associated therewith. The appropriate reinforcement obtained can be realized. The other reinforcing member preferably has a boundary between a web and an upper flange of the beam, where a value of a compressive strain or a tensile strain generated in a cross section of the web of the beam when the beam is subjected to bending force is maximized. And a height position at which the compressive strain or the tensile strain is half of the maximum value.

  The upright portion of the one reinforcing structure and the upright portion of the other reinforcing structure are respectively a single plate member, or one plate member and two plates that are respectively orthogonally connected to the plate member. And a member.

It is a perspective view of the column-and-beam joint part of a through diaphragm type provided with a reinforcement structure. It is the longitudinal cross-sectional view obtained along one cut surface of a beam-column joint part. However, for the purpose of clarifying the drawing, hatching is not applied to the upper and lower flanges and the cross section of the web. FIG. 4 is a longitudinal sectional view taken along another cut surface of the column-beam joint, which is perpendicular to the one cut surface. As in FIG. 2, hatching is omitted in the cross section of the upper and lower flanges and the web for the purpose of clarifying the drawing of the beam. 4 is a cross-sectional view of the beam-column joint taken along line 4-4 in FIG. 2; However, beams are shown by imaginary lines in order to clarify the drawing.

  Referring to FIG. 1, a reinforcement structure applied to a through-diaphragm beam-to-column joint 10 in a building is indicated by reference numeral 12 as a whole.

  The beam-to-column joint 10 extending in the vertical direction is a square joint steel pipe 14 having a square cross section and having an upper end surface 14a and a lower end surface 14b (see FIG. 2). The upper and lower diaphragms 16 and 18 are joined to the steel pipe at the upper end surface 14a and the lower end surface 14b, respectively.

  In the column-beam joint 10, together with the joint steel pipe 14, upper and lower steel pipes 20, 22 constituting the columns of the building are disposed on the upper and lower diaphragms 16, 18, respectively, and are joined thereto by welding. ing. In addition, four beams 24 constituting the building are joined to the beam-column joint 10 by welding. Each beam 24 is made of steel having an H-shaped cross section, and has upper and lower flanges 24a and 24b and a web 24c connected to these flanges. Each beam 24 is joined to each side surface of the joint steel pipe 14 by welding at its web 24c, and is joined to each peripheral side surface of both upper and lower diaphragms 16 and 18 at both upper and lower flanges 24a and 24b by welding. I have. The number of beams 24 to be joined to the beam-to-column joint 10 may be any of 1 to 3 instead of the illustrated example in which the number of the beams 24 is four.

  The reinforcing structure 12 applied to the beam-column joint 10 includes one reinforcing member 26. Preferably, in addition to one reinforcement member 26, another reinforcement member 28 is included.

  As shown in FIG. 2, one reinforcing member 26 includes a lower half portion 14L of the joint steel pipe 14 (a cross section S at an intermediate position between upper and lower end faces 14a and 14b of the joint steel pipe 14 and a lower end face of the joint steel pipe 14). 14b). The other reinforcing member 28 is disposed in the upper half portion 14U (a portion between the cross section S of the joint steel pipe 14 and the upper end surface 14a of the joint steel pipe 14).

  As shown in FIGS. 1 to 3, one reinforcing member 26 includes a steel plate portion 26 a and a steel standing plate portion 26 b joined to the plate portion and perpendicular to the plate portion 26 a. The other reinforcing member 28 is a steel flat plate portion 28a similar to the flat plate portion 26a of the one reinforcing member 26, and is connected to the flat plate portion 28a and is perpendicular to the flat plate portion 28a. (See FIGS. 1 to 4).

  The flat plate portions 26a and 28a of the reinforcing members 26 and 28 have a square planar shape that is substantially the same as the cross-sectional shape of the joint steel pipe 14. On the other hand, each of the upright portions 26b and 28b preferably has an elongated rectangular shape as a whole, and the other two sides of the two sides of the square, which is the planar shape of each of the flat portions 26a and 28a, are connected to each other. It extends parallel to the sides. Each of the upright plates 26b and 28b has a shape other than the rectangular shape, instead of the illustrated example, and can be arranged at an arbitrary position on each of the flat plates 26a and 28a. The length of each of the upright portions 26b and 28b can be set arbitrarily, and is preferably equal to the length of one side of the square, which is the planar shape of each of the flat portions 26a and 28b. The height (width) of the upright portion 26b is within the range of the distance between the flat portion 26a and the lower diaphragm 18, and the height (width) of the upright portion 28b is the flat portion. The distance can be arbitrarily determined within the range of the size of the interval between 28a and the upper diaphragm 16. The reinforcing members 26, 28 have a higher reinforcing ability as the height dimension of each of the standing plate portions 26b, 28b is larger. When the upper and lower scallops 30 and 32 are formed on the web 24c of the beam 24 as in the example shown in the figure, as shown in FIG. The upper edge 28b2 of the standing plate portion 28b of the other reinforcing member 28 is defined so as to be located in the formation area of the scallop 32 and the formation area of the scallop 30 in the height direction which is the axial direction of the joint steel pipe 14, respectively. Is desirable. The thickness of each of the flat plate portions 26a and 28a and each of the upright plate portions 26b and 28b can be set to be substantially the same as the thickness of the joint steel pipe 14, for example.

  As shown in FIGS. 1 and 2, the flat plate portion 26 a of the one reinforcing member 26 is arranged parallel to the lower end surface 14 b of the joint steel pipe 14 and has a peripheral edge 26 a 1, more specifically, over the entire peripheral edge 26 a 1. It is joined to the inner wall surface 14c of the joint portion steel pipe 14 by welding. In addition, the standing plate portion 26b is welded to the inner wall surface 14c of the joint steel pipe 14 by welding on the two side edges 26b1, more specifically, over all of the side edges 26b1, and to the lower end surface 14b of the joint steel pipe 14. It is growing towards. On the other hand, the flat plate portion 28a of the other reinforcing member 28 is arranged in parallel with the upper end surface 14a of the joint steel pipe 14 and, more specifically, at the peripheral edge 28a1, more specifically, over the entire peripheral edge 28a1, the inner wall surface 14c of the joint steel pipe 14 Are joined by welding. In addition, the upright portion 28b is welded to the inner wall surface 14c of the joint portion steel pipe 14 by welding at the two side edges 28b1, more specifically, over the entire side edge 28b1, and to the upper end surface 14a of the joint portion steel tube 14. It is growing towards.

  Each of the upright plate portions 26b and 28b is made of a single plate member, and instead of the illustrated example in which the whole has a-(minus) plane shape, the one plate member and both side surfaces of the plate member are respectively provided. It is composed of two plate members 34 (shown by imaginary lines in FIG. 1) that are arranged in a row at right angles, and can have a + (plus) plane shape as a whole. The two plate members 34 are joined by welding to the inner wall surface 14c of the joint steel pipe 14 at the side edges located at these free ends. By doing so, the reinforcing ability of each of the reinforcing members 26 and 28 can be further enhanced.

  When the building is subjected to the seismic force, which causes a bending force to act on the beam 24 to generate a bending moment, the joint steel pipe 14 of the beam-column joint 10 is moved from the beam 24 to an axis caused by the bending moment. Receive directional force. The one reinforcing member 26 and the other reinforcing member 28 attached to the joint steel pipe 14 serve to suppress local deformation of the joint steel pipe 14 due to the axial force transmitted from the beam 24, respectively. . By suppressing the local deformation of the joint steel pipe 14, it is possible to minimize the reduction in the strength of the web 24c of the beam 24, that is, the reduction in the ability to bear the bending moment. As a result, it is not necessary to adopt a beam 24 having a large cross section in anticipation of a reduction in the proof strength of the web 24c, thereby adopting a beam 24 having a smaller cross section and thus a lighter weight, and thus reducing the weight and building cost of the building. Reduction and enable. Also, the corresponding stress load on the web 24c reduces the stress load on both flanges 24a, 24b, thereby leading to fracture of the welded end of the beam 24 or buckling of the web 24c and the flanges 24a, 24b of the beam 24. The deformation performance of the beam 24 is improved.

  The transmission of the axial force to the joint steel pipe 14 is mainly performed through the upper and lower flanges 24 a and 24 b of the beam 24 and the upper and lower diaphragms 16 and 18. Since the floor slab FS (FIG. 2) constituting the building exists on the upper flange 24a of the beam 24, a part of the axial force transmitted along the upper flange 24a is borne by the floor slab FS. You. For this reason, the magnitude of the axial force transmitted along the upper flange 24a is smaller than the magnitude of the axial force transmitted along the lower flange 24b.

  Under the circumstances described above, the lower flange 24b of the beam 24 is joined, and thus the lower half of the joint steel pipe 14 that may receive a relatively large axial force and cause a relatively large local deformation. One reinforcing member 26 is disposed in the lower half 14L of the joint steel pipe 14 to reinforce the 14L. The one reinforcing member 26 can be arranged at an arbitrary height position in the lower half portion 14L of the joint steel pipe 14, but the arrangement position is preferably determined in consideration of the following.

  The bending force of the beam 24, that is, the bending force (positive bending force) in which a tensile stress is generated in the lower flange 24b of the beam 24 or the bending force (negative bending force) in which a compressive stress is generated in the lower flange 24b of the beam 24 ), The cross section of the web 24c of the beam 24 (the cross section assuming the plane is maintained) is distorted.

  Due to the distribution of the strain generated in the cross section of the web 24c of the beam 24 in the positive bending, the boundary between the web 24c and the lower flange 24b is determined from the height position of the boundary 24c1 (see FIG. 2) between the web 24c and the upper flange 24a. It changes linearly from compressive strain to tensile strain up to the height position of 24c2. At this time, the compressive strain is maximized at the height of the boundary 24c1 between the web 24c and the upper flange 24a, and the tensile strain is maximized at the height of the boundary 24c2 between the web 24c and the lower flange 24b.

  Also, in the negative bending, the strain generated in the cross section of the web 24c of the beam 24 is distributed due to the distribution of the boundary 24c2 between the web 24c and the lower flange 24b from the height position of the boundary 24c1 between the web 24c and the upper flange 24a. It changes linearly from tensile strain to compressive strain up to the height position. At this time, the tensile strain becomes maximum at the height of the boundary 24c1 between the web 24c and the upper flange 24a, and the compressive strain becomes maximum at the height of the boundary 24c2 between the web 24c and the lower flange 24b.

  As described above, the magnitude of the axial force on the upper flange 24a is smaller than the magnitude of the axial force on the lower flange 24b. From this, the absolute value of the compressive strain is smaller than the absolute value of the tensile strain in the positive bending, and the absolute value of the tensile strain is smaller than the absolute value of the compressive strain in the negative bending.

  In consideration of the above, one reinforcing member 26 disposed in the lower half portion 14L of the joint steel pipe 14 has a tensile strain at the time of the positive bending or a tensile strain at the time of the negative bending in order to exhibit its reinforcing effect. It is desirable to be located at a location where the compression strain is relatively large. For this reason, one reinforcing member 26 (more specifically, the flat plate portion 26a) has a height of the boundary 24c2 between the web 24c of the beam 24 and the lower flange 24b at which the value of the tensile strain or the value of the compressive strain is maximized. And a height position (a position above the boundary 24c2 in the figure) at which the tensile strain and the compressive strain have half the maximum value.

  For the same reason as described above, the other reinforcing member 28 disposed in the upper half portion 14U of the joint steel pipe 14 also has a compressive strain at the time of the positive bending or the negative bending at the time of exhibiting the reinforcing effect. It is desirable that the tensile strain at the time is in a relatively large place. For this reason, the other reinforcing member 28 (more specifically, the flat plate portion 28a) has a height of the boundary 24c1 between the web 24c of the beam 24 and the upper flange 24a at which the value of the compressive strain or the value of the tensile strain is maximized. And a height position (a position below the boundary 24c1 in the figure) at which the tensile strain or the compressive strain is half of the maximum value.

  When the axial force is transmitted to the lower half portion 14L of the joint steel pipe 14 through the lower flange 24b of the beam 24, the flat plate portion 26a of the one reinforcing member 26 mainly exerts a reinforcing action on the lower half portion 14L to lower the lower half portion 14L. Suppress the occurrence of local deformation on the half. At this time, the upright plate portion 26b of the one reinforcing member 26 performs a reinforcing function of the lower end of the joint steel pipe 14 and its vicinity, and also applies the axial force applied to the lower end of the joint steel pipe 14 and its vicinity to the flat plate part. 26a, and reinforces the flat portion to suppress local deformation thereof.

  Similarly, when the axial force is transmitted to the upper half portion 14U of the joint steel pipe 14 through the upper flange 24a of the beam 24, the flat plate portion 28a of the other reinforcing member 28 similarly acts to reinforce the upper half portion 14U. To suppress the occurrence of local deformation in the upper half. At this time, the upright portion 28b of the other reinforcing member 28 performs a reinforcing function of the upper end of the joint steel pipe 14 and its vicinity, and also applies the axial force applied to the upper end of the joint steel pipe 14 and its vicinity to the flat plate portion. 28a, and reinforces the flat portion to suppress local deformation.

  Due to the above-mentioned operation of each of the upright portion 26b of the one reinforcing member 26 and the upright portion 28b of the other reinforcing member 28, a plurality of plates similar to the flat portion at the lower end of the joint steel pipe 14 and in the vicinity thereof. The disposition of the members is unnecessary, and the disposition of the plurality of plate members similar to the flat plate portion at the upper end of the joint portion steel pipe 14 and the vicinity thereof can be dispensed with, thereby disposing the plurality of plate members. In this case, it is possible to avoid welding of the plate member to the joint steel pipe 14 and the accompanying deterioration in quality of the joint steel pipe 14 and deterioration in the performance of the joint steel pipe.

DESCRIPTION OF SYMBOLS 10 Column-beam joint part 12 Reinforcement structure 14 Joint steel pipes 14a, 14b Upper and lower end faces 14U, 14L of joint steel pipe Upper half and lower half 16, 18 of joint steel pipe Upper diaphragm and lower diaphragm 20, 22 Column Steel pipe 24 Beams 24a, 24b, 24c Upper flange, lower flange and web 26 Reinforcement members 26a, 26b One flat member and upright plate portion 28 One reinforcement member 28a, 28b Other reinforcement members 28a, 28b Flat part and standing part FS Floor slab

Claims (4)

Comprising a junction steel tube rectangular having upper and lower end surfaces, and a diaphragm and a lower diaphragm after being joined respectively at its upper and lower end surfaces the bonding portion steel pipe, made of steel having a cross-sectional shape of the H-shaped beam Is a reinforcing structure of a beam-column joint of a building that is joined to the joint steel pipe and the upper and lower diaphragms at the web and upper and lower flanges, respectively.
Including one reinforcing member disposed in the lower half of the joint steel pipe, and another reinforcing member disposed in the upper half of the joint steel pipe ,
The one reinforcing member includes a steel flat plate portion parallel to a lower end surface of the joint steel pipe, and a steel standing plate portion extending vertically from the flat plate portion toward the lower end surface of the joint steel pipe , The flat plate portion and the upright plate portion of the one reinforcing member are joined by welding to the inner wall surface of the joining portion steel pipe at its peripheral edge and its side edge, respectively .
The other reinforcing member includes a steel flat plate parallel to an upper end surface of the joint steel pipe, and a steel standing plate vertically extending from the flat plate toward the upper end surface of the joint steel pipe, A reinforcing structure for a beam-column joint of a building , wherein a flat plate portion and an upright plate portion of another reinforcing member are joined by welding to an inner wall surface of the joining steel pipe at a peripheral edge and a side edge thereof, respectively .   The one reinforcing member is a web of the beam, wherein a value of a tensile strain or a compressive strain generated in a cross section of the web of the beam in a lower half portion of the joint steel pipe when the beam is subjected to a bending force is maximized. The reinforcing structure for a beam-column joint according to claim 1, wherein the height is between a height position of a boundary between the lower flange and the lower flange, and a height position at which the tensile strain or the compressive strain is a half of the maximum value. . The other reinforcing member is a web of the beam, wherein a value of a compressive strain or a tensile strain generated in a cross section of the web of the beam in an upper half portion of the joint steel pipe when the beam is subjected to a bending force is maximized. is between the height position of the boundary between the upper flange, the compressive strain or tensile strain and half the value become the height position of the maximum value, the reinforcing structure of the beam-column joint according to claim 1 . The reinforcing structure for a beam-column joint according to claim 1 , wherein the upright plate portion includes one plate member, or one plate member and two plate members each of which is orthogonal to the plate member. .

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