JP2015224517A - Joining structure of beam end part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joining structure of a beam end part capable of improving a fatigue resistant characteristic-deformation performance of a beam, while avoiding a preceding yield of a beam end joining part by low-cost construction, as a joining structure of the beam end part in a steel structure for constituting the beam of H-shaped steel.SOLUTION: As a joining structure of a beam end part in a steel structure constituted of a column (a steel frame column) 1 and a beam (such as H-shaped steel) 2, after a beam flange of the beam end part of a beam end joining part low in bearing force burden capacity, is expanded in a width or increased in a thickness by a reinforcement plate 6 (such as width expanding plates 6A and 6B or a thickness increased plate 6C) of one-sheet plate, a flange of the beam is reduced in a cross-section by hole boring processing within a range in the axial direction of a width expanded or thickness increased material in its beam end part, so that a beam cross-sectional position of applying the hole boring processing is precedently yielded to the predicted bending moment distribution.

Description

  The present invention relates to a joint structure of a beam end portion in a steel structure including a beam composed of a beam member (typically H-shaped steel) in which a plate element bears a tensile force generated by a bending moment.

  Conventionally, in a steel structure provided with a beam composed of a column (steel column) and a beam member (typical example is H-shaped steel) in which a plate element bears a tensile force generated by a bending moment, FIG. As shown in a plan view in FIG. 1 and an elevation view in FIG. 1 (b), when the ends of the beam 2 (beam flange 2a, beam web 2b) are welded to the column 1 (column skin plate 1a) at the construction site, The cross-sectional performance of the beam end joint 3 (particularly, the load bearing load ratio of the beam web 2b) is reduced due to restrictions on the construction conditions, and strain due to the moment generated in the beam 2 during an earthquake is likely to concentrate near the beam end joint 3. There were problems in terms of fatigue resistance and deformation ability as structural members. In FIG. 1, 4 is a diaphragm and 5 is a scallop.

  With respect to this problem, as shown in a plan view in FIG. 2 (a) and an elevation view in FIG. 2 (b), a rectangular reinforcing plate 76 is generally welded to the width front ends of the column skin plate 1a and the beam flange 2a. In the conventional method of reinforcing the beam end 31, although the prior yielding / breakage of the beam end joint 3 can be avoided, the stress is concentrated on the end 76 a opposite to the beam end joint 3 of the reinforcing plate 76. Since the stress concentration portion 76a overlaps with the weld bead, there is a limit to improvement in fatigue resistance and deformation performance.

  On the other hand, in order to solve the above-mentioned problems, Patent Documents 1 and 2 disclose a technique for improving fatigue resistance and deformation capacity by reinforcing a beam end with a reinforcing plate provided with a notch. Has been.

  That is, in Patent Document 1, as shown in a plan view in FIG. 12, a reinforcing plate 86 having a curved notch 89 is welded to the column skin plate 1a and the beam flange 2a width front end portion of the beam end portion 31. By providing a hole 87 in the beam flange 2a in the vicinity of the notch 89, the notch 89 yields in advance.

  In Patent Document 2, as shown in a plan view in FIG. 13, two types of reinforcing plates (reinforcing plate 96a and reinforcing plate 96b) are placed at a predetermined interval at the beam flange 2a width front end portion of the beam end portion 31. In addition to welding, by providing a notch 99 from the reinforcing plate 96a to the reinforcing plate 96b including the beam flange 2a portion between the reinforcing plate 96a and the reinforcing plate 96b, the notch 99 yields in advance. Yes.

However, the technique described in Patent Document 1 has the following problems.
-Since the notch 89 is formed in the reinforcing plate 86, a curved process is required, resulting in high cost.
In the case of the field welding type joining type, in order to avoid the prior yielding of the beam end joint 3, it is necessary to increase the width of the reinforcing plate 86 on the beam end joint 3 side and to perform a large width reduction process at the notch 89. There is.
-When the perforated part 87 is provided in the vicinity of the notch part 89, damage concentrates only on that part.

The technique described in Patent Document 2 also has the following problems.
-In order to form the notch part 99, the process which cuts the two types of reinforcement board 96a, 96b and the beam flange 2a between them is high-cost.
-Since the weld bead 100 is located in the vicinity of the preceding yield cross-section part (notch 99), stress concentration may occur in that part, and the fatigue characteristics may be deteriorated.
In order to avoid the above stress concentration, it is necessary to cut the weld bead 100 in the vicinity of the preceding yield cross section.

  On the other hand, in order to solve the above-described problem, in Patent Document 3, as shown in FIG. 14, the beam end portion is reinforced by a linear reinforcing plate 106 and a cross-section 108 having a hole portion 107 is used. A technique for improving fatigue resistance / deformability by pre-breaking is disclosed.

  On the other hand, in Patent Document 4, as shown in FIG. 15, the beam flange portion at the beam end is not reinforced by using a reinforcing plate, but one end of the widening plate 116 cut out from a single plate is used as the column 3. A technique of joining and joining the other end 116a to the beam general portion is also disclosed. In FIG. 15, reference numeral 118 denotes a preceding yield cross section.

  In addition, the following Non-Patent Documents 1 and 2 are cited in the [Example 1] section described later, and the following Non-Patent Document 3 is cited in the [Example 2] section. Keep it.

JP 2001-207533 A JP 2004-353419 A JP 2014-31703 A JP 11-158999 A

Guideline for preventing brittle fracture of steel beam end welds, the same commentary, September 2015 Through-Diamond Steel Tubular Columns-Strength and Deformation Performance of H-Shaped Beams, Architectural Institute of Japan, 389, July, S63 Steel Structure Design Standard-Allowable Stress Design Method-4th Edition, Architectural Institute of Japan, September 2005

  However, the technique described in Patent Document 3 has the following problems.

  That is, when the beam span becomes long, it is necessary to lengthen the reinforcing plate 106 in proportion to the beam span in order to avoid the occurrence of cracks at the end portion 106a of the reinforcing plate 106. As a result, the reinforcing plate 106 becomes elongated, and it is necessary to correct the “warp” at the time of cutting, and the weld length at the time of joining to the beam flange increases, which increases the number of processing steps.

  Further, the technique described in Patent Document 4 has the following problems.

  In other words, the design with the leading yield section 118 at the position where the beam flange starts to widen is the case with the highest fatigue resistance (deformation performance). However, since the entering corner yields, the entering corner is cut. Surface smoothness affects fatigue resistance. When the plate is thick, gas cutting is generally used, but the smoothness of the gas cut surface is low, and man-hours are required for processing to ensure smoothness.

  The present invention has been made in view of the circumstances as described above. As a joining structure of a beam end portion in a steel structure in which a beam is composed of H-shaped steel or the like, the beam end joining is performed by low-cost construction. An object of the present invention is to provide a beam end joint structure that can improve the fatigue resistance and deformation performance of a beam while avoiding the prior yielding of the beam.

  In order to solve the above problems, the present invention has the following features.

  [1] In a steel structure including a column and a beam in which a plate element bears a tensile force generated by a bending moment, the plate element at a beam end including a joint to the column of the beam is a general portion of the beam. Is widened in multiple stages from the joint to the column, and both sides have a straight line shape, and are subjected to drilling at multiple points in the material axis direction at the intermediate stage of the widening and predicted bending It is configured so that the beam cross-sectional position subjected to the drilling process yields in advance with respect to the moment distribution, and at least one part from the portion where the plate element starts to widen to the joint to the column is a single plate Beam end joint structure characterized by being cut out from

  [2] In a steel structure including a column and a beam in which the plate element bears a tensile force generated by a bending moment, the plate element at the beam end including the joint to the column of the beam is a general portion of the beam Widened in one step or multiple steps from the joint to the pillar, and both sides have a straight line shape, and drilling is performed at multiple points in the material axis direction at the widening part, and is predicted For the bending moment distribution, the cross-sectional position of the beam subjected to the drilling process is configured to yield in advance, and at least one portion from the portion where the plate element starts to widen to the joint to the column A beam end joint structure characterized by being cut out from a plate.

  [3] In a steel structure including a column and a beam in which the plate element bears a tensile force generated by a bending moment, the plate element at the beam end including the joint to the column of the beam is a general portion of the beam. Thickening is performed toward the joint from the pillar to the pillar, and the thickened portion is subjected to drilling at a plurality of locations in the material axis direction, and the drilling is applied to the predicted bending moment distribution. The cross-sectional position of the beam is configured to yield in advance, and at least from the portion where the thickening of the plate element starts to the junction to the column is cut out from a single plate. Beam end joint structure.

  [4] The plate element having the widened portion or the thickened portion and the plate element of the general portion of the beam are joined, and the vicinity of the joint portion to the column on both sides of the plate element having the widened portion or the thickened portion and the beam The beam end portion according to any one of the above [1] to [3], which has semicircular notches formed by drilling at a total of four locations in the vicinity of the joint portion of the general portion to the plate element Bonding structure.

  According to the present invention, as a joint structure of a beam end in a steel structure in which the beam is composed of H-shaped steel or the like, the beam endurance is prevented while avoiding the prior yielding of the beam end joint by low-cost construction. Fatigue characteristics and deformation performance can be improved.

It is a figure which shows the joining structure of the beam end part which is the conventional unreinforced. It is a figure which shows the joining structure of the beam end part reinforced by the prior art. It is a figure which shows the joining structure of the beam end part in Embodiment 1 of this invention. It is a figure which shows the junction structure of the beam end part in Embodiment 2 of this invention. It is a figure which shows the other example of the junction structure of the beam end part in Embodiment 2 of this invention. It is a figure which shows the joining structure of the beam end part in Embodiment 3 of this invention. It is a figure which shows the junction structure of the beam end part in Embodiment 4 of this invention. It is a figure which shows the boarding example of the widening material in Embodiment 5 of this invention. It is a figure which shows the boarding example of the widening material in Embodiment 5 of this invention. In Example 1, it is a figure which shows the deformation | transformation capability of Examples 1-3 of this invention. In Example 1, it is a figure which shows the deformation capability of the prior art examples 1 and 2. FIG. It is a figure which shows the junction structure of the beam end part in patent document 1. FIG. It is a figure which shows the junction structure of the beam end part in patent document 2. FIG. It is a figure which shows the junction structure of the beam end part in patent document 3. FIG. It is a figure which shows the junction structure of the beam end part in patent document 4. FIG.

  In the embodiment of the present invention, the beam end portion of the beam end joint portion having a low proof stress bearing capacity is used as the joint structure of the beam end portion in the steel structure composed of the column (steel column) and the beam (H-shaped steel or the like). The beam flange is widened or thickened with a single plate reinforcing plate (widening plate or thickening plate), and the beam flange is placed within the widened or thickened axial range at the end of the beam. By reducing the cross-section by drilling, the beam cross-sectional position where the drilling is performed yields the expected bending moment distribution in advance, thereby reducing the beam resistance in low-cost construction. The fatigue characteristics and deformation performance are improved. In addition, a beam end joint part refers to the surface where the beam end part and the column were joined.

  Embodiments (Embodiments 1 to 5) of the present invention will be described below with reference to the drawings.

[Embodiment 1]
FIGS. 3A and 3B are diagrams showing a joint structure of beam ends in the first embodiment of the present invention. FIG. 3A is a plan view, and FIG.

  As shown in FIG. 3, in the first embodiment, as the joint structure of the beam end portion 31 in the steel structure composed of the column (steel column) 1 and the beam (H-shaped steel) 2, the load bearing capacity is low. The beam flange of the beam end portion 31 having the beam end joint portion 3 is constituted by the reinforcing plate 6 (widening plate 6A), one end of the widening plate 6A is welded to the column 1 (column skin plate 1a), and the other end is beamed. It welds to the beam flange 2a of 2 general parts (part provided with the normal beam flange).

  Here, the widening plate 6 </ b> A widens in two steps from the general portion of the beam 2 to the joint portion of the column 2, and both sides thereof are configured by straight lines. That is, the widening plate 6A has a side parallel to the beam axis direction of the beam 2 and has a narrow width opposite to the column 1 (the same width as the beam flange width of the general portion of the beam 2), and the column 1 side. The width is a three-stage width of a wide portion and an intermediate width portion (intermediate width portion) 6d, and the portion where the width changes is composed of sides forming 45 degrees from the material axis direction of the beam 2. Yes.

  Then, within the range of the intermediate width portion 6d which is a portion after being widened by one step (that is, within the range of the intermediate step of widening), a plurality (in this case, two locations) in the width direction and a plurality in the material axis direction Holes 7 are provided at locations (here, 4 locations).

  As a result, after the yield of the beam cross-sectional position 8 where the drilling portion 7 closest to the column 1 exists in the material axis direction with respect to the predicted bending moment distribution, the beam 1 sequentially starts from the column 1 in the material axis direction. The cross-sectional position of the beam where the perforated portion 7 in the direction of moving away exists yields.

  The widening plate 6A is a single plate at least from the portion where the widening starts (here, the corner 6c on the side close to the general portion of the beam 2) to the joint 1 (beam end joint 3) to the column 1. It is made of a single plate that is cut out from and not joined by welding or the like.

  Note that the side of the intermediate width portion 6d is not parallel to the material axis of the beam 2, and the bending strength after considering the deficiency of the perforated portion 7 is inclined so as to be proportional to the moment distribution in the material axis direction of the beam 2. Thereby, each cross section of the perforated part 7 can yield at the same time, and the deformation performance can be further improved.

  Further, the beam end joint portion 3 of the beam end portion 31 widened by the widening plate 6A can maintain a macroscopic elastic state until at least one of the beam cross-sectional positions where the perforated portion 7 exists reaches the total plastic moment. It is preferable to have proof stress.

  Further, it is desirable that the portion corresponding to the length of the scallop 5 of the beam 2 has a cross-sectional performance such that the cross-section does not yield even after the yield strength is increased by strain hardening of the preceding yield cross-section portion 8. This is because when the yield strength ratio between the scallop 5 portion and the preceding yield cross section 8 is small, the strain at the bottom of the scallop 5 increases after the yield strength is increased by strain hardening, and there is a risk of rupture starting from the crack at the bottom of the scallop 5. Because.

  In addition, as for the length of the widening plate 6A, the cross section of the end 6a far from the column 1 of the widening plate 6A may have a length that does not yield even after the yield strength increase due to strain hardening of the preceding yield cross-section portion 8. desirable. This is to prevent cracks from occurring at the welded portion where the widening plate 6A and the beam flange 2a are joined after the yield strength is increased by strain hardening.

  In addition, the diameter of the perforated portion 7 is appropriately designed, and the total plastic moment of the widened portion excluding the vicinity of the scallop 5 portion is set to the collapse mode of the structure (usually in a state where plastic hinges are generated at both ends of the beam 2). By making it proportional to the moment gradient at, it is possible to make the progress of plasticization of the preceding yield cross-section part 8 uniform and to further improve the fatigue resistance / deformability.

  Further, the ratio of the width of the preceding yield cross section 8 to the beam flange thickness in the widening plate 6A is preferably set to a value that does not cause buckling at an early stage, but is necessary to prevent a sudden decrease in the proof stress due to the beam flange fracture. In addition to ensuring the performance, a value that makes the fracture mode of the beam 2 after widening the local buckling of the widening plate 6A can be adopted.

  Further, an R portion may be provided at the corner 6c where the width of the widening plate 6A is changed in order to avoid stress concentration.

  Thus, in the first embodiment, the following effects can be obtained.

  (A) By widening the beam end portion 31 with the widening plate 6A, it is easy to avoid prior yielding of the beam end joint portion 3 even in the on-site welding type.

  (B) By widening the beam end portion 31 with the widening plate 6A, the beam end joint portion due to a reduction in the yield strength of the beam end joint portion due to cross-sectional defects due to the scallop 5 or out-of-plane deformation of the column skin plate 1a at the beam web joint portion. Deformation concentration in the vicinity of 3 can be eliminated.

  (C) By providing the perforated portion 7 in the widened plate 6A at the beam end portion 31, it is possible to separate particularly the stress concentration location of the preceding yield cross section 8 from the weld line and the cut corner cut surface of the plate. Incidentally, in Patent Document 2, as shown in FIG. 13, the weld bead 100 is located in the vicinity of the preceding yield cross section (notch 99), so stress concentration occurs at that location, and fatigue characteristics may deteriorate. was there. Moreover, in the said patent document 4, there existed a possibility that a fatigue characteristic might fall, since the stress concentration location and the entering corner cut surface of a board were adjoining. From the viewpoint of fracture mechanics, the perforated portion 7 can be regarded as a kind of internal defect. Internal defects also have the advantage of less stress concentration than surface defects.

  (D) By providing the perforated portions 7 at a plurality of locations in the material axis direction on the widening plate 6A of the beam end portion 31, the yield range of the beam 2 can be expanded.

  (E) The processing cost can be reduced by using the widening plate 6A made of straight sides and using the cross-section reducing method by drilling that allows drilling.

  (F) Since the widening plate 6A is composed of a single plate from at least the portion where the widening starts to the joint portion to the column 1, it is necessary to correct the warp when the reinforcing plate is cut out as in Patent Document 3. It is possible to avoid such a problem that the welding length of the reinforcing plate to the beam flange becomes long and the number of processing steps increases.

  (G) According to the above (a) to (f), it is possible to realize a column beam joint having excellent fatigue resistance and deformation ability by low-cost construction.

  (H) Furthermore, since the drilling is performed after reinforcing the original beam cross section, it is possible to maintain a cross-sectional performance equal to or higher than that of the original beam cross section, and there is also an effect that there is no design disadvantage.

  (I) Further, the length of the portion (non-widened portion) having the same width as the beam flange 2a of the widening plate 6A is equal to the length of the portion widened in two steps, and the amount of widening in the first step and the second step is equal. When the angle of the step angle portion (inclined portion) 6b with the beam widening is made equal to the beam material axis, it is possible to form the sides of the two widening plates 6A by one cut, and the processing man-hour is reduced. This has the effect of improving the yield of the plate.

  In the first embodiment, the widening plate 6A is widened in two stages from the general portion of the beam 2 to the joint portion of the beam 2, but the widening plate 6A is expanded from the general portion of the beam 2 to the column 2. You may make it widen in multiple steps | paragraphs of 3 steps or more toward the junction part.

[Embodiment 2]
FIGS. 4A and 4B are diagrams showing a joining structure of beam end portions according to the second embodiment of the present invention. FIG. 4A is a plan view and FIG. FIG. 4C is a view for explaining the arrangement pattern of the perforated portions.

  The beam end joint structure in Embodiment 2 of the present invention is basically the same as the beam end joint structure in Embodiment 1 of the present invention shown in FIG. The shape of 6 and the arrangement pattern of the perforated portions 7 are different.

  That is, as shown in FIG. 4, in this second embodiment, the load bearing capacity is a joint structure of a beam end 31 in a steel structure composed of a column (steel column) 1 and a beam (H-shaped steel) 2. The beam flange of the beam end portion 31 having the low beam end joint portion 3 is composed of a reinforcing plate 6 (widening plate 6B), and one end of the widening plate 6B is welded to the column 1 (column skin plate 1a) and the other end Is welded to the beam flange 2a of the general part of the beam 2.

  Here, the widening plate 6B is widened in one step from the general portion of the beam 2 to the joint portion with the column 1, and both sides thereof are configured by straight lines. That is, the widening plate 6 </ b> B has a shape that increases in width at a predetermined rate as it approaches the pillar 1.

  And the punching part 7 is provided by drilling in the range of the step angle part (inclined part) 6b of the widening plate 6B (that is, in the range of the part that is being widened). The arrangement of the perforated part 7 is by adjusting the arrangement angle of the staggered hole (the hole shifted in the material axis direction when viewed in the width direction) at the point where the cross-sectional yield strength in the widened plate 6B varies depending on the position due to widening, It is possible to design the effective cross section to be proportional to the bending moment distribution generated in the beam or to be equal to the beam flange 2a.

  For example, as shown in FIG. 4C, within the range of the step corner 6b of the widening plate 6B in the material axis direction, a plurality of locations in the material axis direction (here, (a) shown in FIG. In (b) and (c), the effective section examination lines are located at three locations (in this case, a plurality of effective section examination lines (a), (b), and (c) shown in FIG. 4) perforations 7 are provided on the top.

  As a result, the beam cross-sectional positions 8 at a plurality of locations (here, 3 locations) where the perforated portions 7 are present in the width direction simultaneously yield to the predicted bending moment distribution.

  Thus, also in the second embodiment, the effects (a) to (h) can be obtained as in the first embodiment.

  In addition, in the second embodiment, FIG. 5 (a) is an elevation view, FIG. 4 (b) is a plan view, and FIG. 5 (c) is an effective section examination line (a), (b), (c). As shown in (d), as the widening plate 6 (6B ′), both side surfaces can be configured by one straight line. In this case, the widening plate 6B ′ is cut out as compared with the first embodiment. It is even easier.

  In the second embodiment, the widening plate 6B is widened in one step from the general portion of the beam 2 to the joint portion to the column 2, but the widening plate 6B is expanded from the general portion of the beam 2 to the column 2. You may make it expand in multiple steps of two steps or more toward the junction part.

[Embodiment 3]
6A and 6B are diagrams showing a joint structure of beam ends in Embodiment 3 of the present invention. FIG. 6A is a plan view and FIG. 6B is an elevation view.

  The beam end joint structure in Embodiment 3 of the present invention is basically the same as the beam end joint structure in Embodiment 1 of the present invention shown in FIG. The difference is that the thickened plate 6C is used instead of 6A.

  That is, as shown in FIG. 6, in this third embodiment, the load bearing capacity as a joint structure of the beam end portion 31 in the steel structure composed of the column (steel column) 1 and the beam (H-shaped steel) 2. The beam flange of the beam end portion 31 having the low beam end joint portion 3 is constituted by the thickened plate 6C, one end of the thickened plate 6C is welded to the column 1 (column skin plate 1a), and the other end is welded to the beam 2 It is welded to the beam flange 2a of the general part.

  Here, the thickening plate 6 </ b> C is thickened from the general part of the beam 2 toward the joint part to the column 2. That is, in FIG. 6, the thickening plate 6 </ b> C is increased by one step from the thickness of the general beam flange 2 a, but the thickening plate 6 </ b> C can be gradually increased as it approaches the column 1. good.

  In the thickening plate 6C, a plurality of (in this case, two) perforations 7 in the width direction and a plurality of (in this case, four) in the material axis direction are provided.

  As a result, the beam cross-sectional position 8 where the perforated portion 7 exists in the width direction yields ahead of the predicted bending moment distribution.

  Thus, also in the third embodiment, the effects (a) to (h) can be obtained as in the first embodiment.

  In addition, in the third embodiment, both side surfaces of the thickening plate 6C are each formed by one straight line, and the thickening plate 6C can be cut out more easily than in the first embodiment.

[Embodiment 4]
FIG. 7 is a view showing a joint structure of beam ends in Embodiment 4 of the present invention. FIG. 7 (a) is based on Embodiment 1 of the present invention, and FIG. 7 (b) is an embodiment of the present invention. FIG. 7 (c) is based on Embodiment 3 of the present invention.

  In addition to the forms of the first, second, and third embodiments, the joint structure of the beam ends in the fourth embodiment of the present invention is on both sides of the reinforcing plate 6 (the widening plate 6A, the widening plate 6B, and the thickening plate 6C). Semicircular cutouts 7a are provided in a total of four locations near the joint to the column 1 (column skin plate 1a) and near the joint to the beam flange 2a of the general portion of the beam 2.

  The reinforcing plate 6 (the widening plate 6As, the widening plate 6Bs, and the thickening plate 6Cs) provided with such a notch 7a is joined to the column skin plate 1a and the reinforcing plate 6 by the notch 7a. It is possible to suppress the occurrence of cracks from the plate edge of the joint portion with the beam flange 2a, while ensuring the fatigue resistance performance of the beam end portion 31, while widening the joint position to the column skin plate 1a, and the reinforcing plate The length of 6 can be reduced.

  Although not shown in FIG. 7, a semicircular cutout 7a can be similarly applied to the widened plate 6B ′, which is another example of Embodiment 2 of the present invention (widened plate 6B ′s). ).

[Embodiment 5]
As Embodiment 5 of the present invention, a drawing of the widening plate shown in Embodiments 1 and 4 of the present invention will be shown.

  FIG. 8 (a) shows the widening plate 6A in the first embodiment of the present invention, FIGS. 8 (b), 9 (c) and 9 (d) show the widening plates 6As and 6Bs in the fourth embodiment of the present invention, respectively. , 6B's.

  In any planing, since it can be arranged without a gap between the adjacent widening plates, it is possible to reduce the man-hour for cutting. Also, the yield of the plate is improved.

  Further, in FIGS. 8 (b), 9 (c), and 9 (d), in order to form the semicircular cutout 7a, a drilling process is performed before cutting the plate, so that the processing efficiency is improved. Can be improved.

  Although not shown in FIGS. 8 and 9, the widening plate 6 </ b> B according to the second embodiment of the present invention can be cut in the same manner as the widening plate 6 </ b> Bs shown in FIG.

As Example 1 of the present invention, a square steel pipe column having a column diameter of 400 mm and a plate thickness of 16 mm, a length of 500 mm, a width of 200 mm, a beam web thickness of 12 mm, a flange thickness of 19 mm, a scallop length of 35 mm, a yield stress of 412.5 N / mm ² , Examination was performed in the case of joining a beam (H-shaped steel) having a tensile strength of 550 N / mm ² .

  The beam web is a high-strength bolt friction joint, and has a strength section F10T, size M20, twelve in two rows, and a pitch of 55 mm.

  As for the moment distribution of the beam, assuming a case where the distance between the column cores is 6000 mm and antisymmetric bending, a triangular distribution in which the moment of 3000 mm from the column core is 0 is considered.

  And as conventional example 1, the unreinforced beam end joint structure shown in FIG. 1, as conventional example 2, the beam end joint structure reinforced according to the prior art shown in FIG. As shown in FIG. 3, the beam end joint structure in the first embodiment of the present invention, as the present invention example 2, the beam end joint structure in the second embodiment of the present invention shown in FIG. 4, the present invention example 3 As shown in FIG. 6, the beam end joint structure in the third embodiment of the present invention is considered.

  In Example 1 of the present invention, the width of the first and second steps of the widening plate 6A is 75 mm, the width of the position attached to the column is 350 mm, and the width of the intermediate portion is 275 mm. The length of the widening plate 6A is 600 mm. The hole diameter is 37.5 mm, and the hole position closest to the column is at a distance of 200 mm from the column surface.

  In Example 2 of the present invention, the widening width of the widening plate 6B is 150 mm, and the width of the position attached to the column is 350 mm. The length of the widening plate 6B is 700 mm, the length of the inclined portion is 500 mm, and there are 100 mm long parallel portions at both ends. The hole diameter is 30 mm, and the hole position closest to the column is at a distance of 200 mm from the column surface.

  In Example 3 of the present invention, the thickness of the thickening plate 6C is 28 mm. The hole diameter is 32 mm, and the hole position closest to the column is at a distance of 200 mm from the column surface. The length of the thickening plate 6C is 600 mm.

  In addition, the effective cross-sectional height and burden load of the beam web were examined using the method described in Non-Patent Document 1 and Non-Patent Document 2. However, for the high-strength bolt joint, the outer three parts transmit the stress in the beam material axial direction due to the moment, and the other bolts bear the beam shear load. The load of the beam web was set to the smaller value of the proof stress due to the effective web height and the proof strength of the bolt joint.

  Table 1, FIG. 10, and FIG. 11 show the examination results of Invention Examples 1, 2, and 3 and Conventional Examples 1 and 2.

  In Table 1, the beam yield moment of the beam end (column-beam joint surface position, beam end joint), preceding yield site, strengthened plate end site (position on the opposite side of the column), beam shear force at that time, and ultimate strength The beam shear force at the time of (the total plastic moment calculated by the yield strength of the beam flange at the preceding yield site and the beam web (effective section)) is compared.

  FIG. 10 shows the longitudinal distribution of the total plastic moment of the beam and the bending moment distribution at the ultimate strength. FIG. 10 (a) shows Example 1 of the present invention, and FIG. 10 (b) shows Example 2 of the present invention. FIG. 10 (c) shows Example 3 of the present invention, FIG. 11 (d) shows Conventional Example 1, and FIG.

  Incidentally, since the portion where the total plastic moment is lower than the bending moment at the ultimate yield strength is mainly plasticized, the longer the corresponding portion is, the larger the deformability is. On the other hand, since the beam end and the reinforcing plate end overlap with the weld bead, it is better not to yield as much as possible.

  First, in Conventional Example 1 shown in FIG. 11 (d), since the bending strength of the beam end is lower than the total plastic moment when the entire cross section of the beam is effective, strain concentrates in the vicinity of the beam end.

  Further, in the conventional example 2 shown in FIG. 11 (e), the moment that acts on the beam end at the maximum yield strength of the preceding yield site is designed to be equal to or less than the bending strength of the beam end. It is the end on the opposite side of the column and coincides with the end of the weld bead, so stress concentration tends to occur.

  On the other hand, in Examples 1, 2, and 3 of the present invention shown in FIGS. 10 (a), (b), and (c), the moment acting on the beam end at the maximum yield strength of the preceding yield region is less than the bending strength of the beam end. The preceding yield site and the weld bead are separated. However, although the end of the reinforcing plate on the opposite side of the column yields at the maximum yield strength of the preceding yield region, the degree of plasticization is small.

  As Example 2 of the present invention, for the joint structure of the beam end portion in Embodiment 2 of the present invention shown in FIG. 5, the effective cross section of the portion where the perforated portions are arranged in a staggered manner on the widening plate was calculated.

  The beam width of the general portion of the beam is 300 mm, the widening width at the position where the beam is attached to the column is 525 mm, and the length of the inclined portion is 1000 mm. The arrangement of the perforated portions is as shown in FIG.

  And the effective cross section (effective width) in the cross section (break line) of (a), (b), (c), (d) shown in FIG. The effective diameter of the holes arranged in a staggered manner (the effective diameter coefficient in Table 2) was calculated using the effective hole diameter evaluation formula described in Chapter 13 (pp. 101) of Non-Patent Document 3.

  Table 2 shows the calculation results. In any cross section, the effective width is 300 mm.

1 Column 1a Column skin plate 2 Beam 2a Beam flange 2b Beam web 3 Beam end joint 4 Diaphragm 5 Scallop 6 Reinforcement plate (widening plate, thickening plate)
6A Widening plate 6As Widening plate 6B Widening plate 6Bs Widening plate 6B 'Widening plate 6B's Widening plate 6C Thickening plate 6Cs Thickening plate 6a End of the widening plate on the opposite side 6b Widening plate step angle (inclined portion)
6c Corner of the widening plate 6d Intermediate width portion of the widening plate 7 Perforated portion 7a Semi-circular cutout 8 Preceding yield cross section 31 Beam end portion 76 Reinforcement plate 76a End of reinforcement plate opposite to beam end joint Part 86 Reinforcing plate 87 Perforated part 89 Curved notch 96a, 96b Reinforcing plate 99 Curved notch 106 Reinforcing plate 106a End of reinforcing plate opposite to column 116 Widening plate 116a Widening plate from opposite side of widening plate Edge 118 Preceding yield section

Claims (4)

  In a steel structure consisting of a column and a beam in which the plate element bears the tensile force generated by the bending moment, the plate element at the beam end including the joint to the column of the beam extends from the general part of the beam to the column. Widening in multiple steps toward the joint, and both sides have a straight line shape, and drilling is performed at multiple locations in the axial direction of the material in the middle of the widening, resulting in an expected bending moment distribution. On the other hand, the cross-sectional position of the beam subjected to the drilling process is configured to yield in advance, and at least the part of the plate element starting from the widening to the joint to the column is cut out from a single plate The joint structure of the beam end part characterized by being made.   In a steel structure consisting of a column and a beam in which the plate element bears the tensile force generated by the bending moment, the plate element at the beam end including the joint to the column of the beam extends from the general part of the beam to the column. The bending moment is widened in one step or multiple steps toward the joint, and both sides have a straight line shape, and are drilled at multiple points in the material axis direction at the widening point. It is configured so that the beam cross-sectional position subjected to the drilling process yields in advance with respect to the distribution, and at least from the part where the plate element starts to widen to the joint to the column from one plate Beam end joint structure characterized by being cut out.   In a steel structure consisting of a column and a beam in which the plate element bears the tensile force generated by the bending moment, the plate element at the beam end including the joint to the column of the beam extends from the general part of the beam to the column. The thickness of the beam is increased toward the joint, and the thickened portion is subjected to drilling at a plurality of locations in the axial direction of the material, and the drilled beam is subjected to the predicted bending moment distribution. The beam end portion is configured such that the cross-sectional position yields in advance, and at least the portion where the thickness of the plate element starts to be joined to the connection portion to the column is cut out from a single plate. Bonding structure.   The plate element having the widened portion or the thickened portion and the plate element of the general portion of the beam are joined, and the vicinity of the joint to the column on both sides of the plate element having the widened portion or the thickened portion and the general portion of the beam The joint structure of the beam end according to any one of claims 1 to 3, which has semicircular notches formed by drilling at a total of four locations in the vicinity of the joint to the plate element.

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