Reinforced h-shaped steel perforated beam

Abstract

To enable economical construction while securing proof stress by effectively reinforcing the periphery of a through hole by using a miniaturized reinforcing member.SOLUTION: A reinforced H-shaped steel perforated beam is an H-shaped steel beam comprising a pair of flanges and a web, wherein a through hole is formed in the web and a reinforcing member is attached to the web at a position adjacent to the through hole. The reinforcing member includes two members separated from each other, and the two members are respectively attached to both sides of the through hole in a region along a straight line that passes through the center of the through hole and is inclined at 45 degrees with respect to the material axis direction of the H-shaped steel beam.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a reinforced H-shaped steel perforated beam.

Background Art

[0002] Since H-shaped steel beams are arranged in the ceiling space of buildings, etc., they may interfere with equipment piping. In order to eliminate this interference, perforated beams with circular or rectangular through-holes provided in the web of the H-shaped steel are generally used. In consideration of the cross-sectional loss due to the through-hole and the reduction in load-bearing capacity due to the fillet deal effect, techniques for attaching a reinforcing member around the through-hole of the perforated beam have been proposed. For example, a method of joining a reinforcing ring to the inner edge of the through-hole as described in Patent Document 1 and a method of joining a reinforcing metal plate to the web around the through-hole as described in Patent Document 2 are known. On the other hand, research on non-reinforced perforated beams without reinforcing the periphery of the through-hole is also being advanced. For example, in Non-Patent Document 1, an evaluation formula for estimating the bending strength and shear strength of the periphery of the through-hole of a non-reinforced perforated beam has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The construction of the reinforcing member as described in the above Patent Document 1 and Patent Document 2 is a large member arranged over the entire circumference inside or outside the through-hole, and thus is not economical from the viewpoints of steel usage and workability. Although these problems can be avoided in a non-reinforced perforated beam, when the web thickness is thin, the web around the through-hole may buckle, and thus the actual load-bearing capacity may be lower than the load-bearing capacity calculated by the evaluation formula.

[0006] Therefore, an object of the present invention is to provide a reinforced H-shaped steel perforated beam that enables economical construction while ensuring the load-bearing capacity by effectively reinforcing the periphery of the through-hole using a miniaturized reinforcing member.

Means for Solving the Problems

[0007] In order to solve the above problems, the reinforced H-shaped steel perforated beam of the present invention has the following configuration. (1) In an H-shaped steel beam including a pair of flanges and a web, a through-hole is formed in the web, and a reinforcing member is attached to the web at a position adjacent to the through-hole. The reinforced H-shaped steel perforated beam is characterized in that the reinforcing member includes two members separated from each other, and the two members are attached to both sides of the through-hole in a region along a straight line inclined at 45 degrees with respect to the material axis direction of the H-shaped steel beam passing through the center of the through-hole. (2) Each of the two members is a steel plate having a planar shape in which one corner of a rectangle is cut out to match the through-hole, and the cut-out portion is arranged along the outer edge of the through-hole. The reinforced H-shaped steel perforated beam according to (1). (3) Each of the two members is a rectangular strip-shaped steel plate, and the long side intersects the straight line and one of the long sides is arranged adjacent to the outer edge of the through-hole. The reinforced H-shaped steel perforated beam according to (1). (4) Each of the two members is a channel steel including a first surface and a second surface. The first surface is attached to the web, the long side of the first surface intersects the straight line, and the second surface is arranged to rise from the long side of the first surface on the through-hole side. The reinforced H-shaped steel perforated beam according to claim 1. (5) The reinforcing member is arranged to be in contact with a parallel line of the straight line in contact with the outer edge of the through hole or to cross the parallel line, and is the reinforced H-shaped steel perforated beam according to any one of (1) to (4). (6) The reinforcing member is welded to the web, and is the reinforced H-shaped steel perforated beam according to any one of (1) to (4). (7) The reinforcing member is bolted to the web, and is the reinforced H-shaped steel perforated beam according to any one of (1) to (4). (8) High-strength bolts are used for the bolt connection, and it is the reinforced H-shaped steel perforated beam according to (7).

Advantages of the Invention

[0008] According to the above configuration, by attaching the reinforcing members separately on both sides of the through hole in the region along the straight line inclined at 45 degrees with respect to the material axis direction of the H-shaped steel beam, while miniaturizing the reinforcing members, the periphery of the through hole can be effectively reinforced, and economical construction can be achieved while ensuring the load-bearing capacity.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] In an H-shaped steel perforated beam with through holes formed in the web, when the web plate thickness is thin, the actual load-bearing capacity may be lower than the load-bearing capacity calculated by the evaluation formula. In such a case, the reinforcing member is considered to be particularly effective. Therefore, first, hereinafter, the behavior of the H-shaped steel perforated beam with respect to the load for each web width-thickness ratio (beam depth / web plate thickness) verified by analysis will be verified, and the tendency of the H-shaped steel perforated beam for which the reinforcing member is particularly effective will be determined.

[0012] Fig. 1 is a diagram showing a model of finite element numerical analysis. In an H-shaped steel beam with a length of 2400 mm, a beam height H = 600 mm, a flange width of 200 mm, and a flange plate thickness of 19 mm as shown in the figure, a perforated H-shaped steel beam with a through-hole having a diameter of 300 mm formed in the web at a position 1200 mm from the beam end to the center and a center height of 300 mm (i.e., the center in the length direction and the beam height direction), the web plate thickness t w Analyses were carried out for 8 cases with different w web plate thickness t w and web width-to-thickness ratio H / t

[0013]

Table 1

[0014] Figs. 2 and 3 are graphs showing the results of the analysis using the model of Fig. 1. Fig. 2 shows the relationship between the forced displacement δ [mm] applied to the beam end and the load P [kN] in the model No. 6 shown in Table 1. The graph of Fig. 2 also shows the yield strength and the full plastic strength of the perforated H-shaped steel beam calculated from the analysis results by the slope factor method. The yield strength is the load when the stiffness becomes 1 / 3 of the initial stiffness K ini , and the full plastic strength is the load when the stiffness becomes 1 / 6 of the initial stiffness K ini .

[0015] Fig. 3 shows the full plastic strength Pp calculated for each of the models No. 1 to No. 8 in the same manner as No. 6 shown in Fig. 2, and the web width-to-thickness ratio H / t of each model wIt shows the relationship with. Note that the full plastic resistance Pp is shown by normalizing with the calculated resistance Qp when the member cross-section is in the fully plastic state. According to the graph in Fig. 3, in the range where the web width-thickness ratio is generally 50 or more, the decrease in Pp / Qp associated with the increase in the web width-thickness ratio, that is, the relatively thinner web plate thickness, is significant. That is, the decrease in the member resistance of the perforated beam is more significant in the range where the web width-thickness ratio is generally 50 or more. Therefore, the reinforcing member according to the embodiment of the present invention as described below can be particularly effective in an H-shaped steel perforated beam with a web width-thickness ratio of 50 or more. Note that even in an H-shaped steel perforated beam with a web width-thickness ratio of less than 50, for example, when it is desired to more reliably maintain the resistance, the reinforcing member according to the embodiment of the present invention may be installed.

[0016] Fig. 4 is a photograph of an H-shaped steel perforated beam deformed by a vertical load. It can be seen that out-of-plane deformation due to web buckling occurs around the through-hole. More specifically, the out-of-plane deformation includes a valley-shaped deformation (when viewed from the front side of the photograph. The same applies hereinafter) along a straight line L inclined at 45 degrees with respect to the length direction of the beam passing near the through-hole, and a mountain-shaped deformation along an elliptical arc C in contact with the outer edge of the through-hole accompanying this deformation. Therefore, it is considered preferable to arrange the reinforcing member for preventing web buckling and maintaining the resistance of the H-shaped steel perforated beam so as to cover the above deformation range. Note that the inclination of the straight line L appears in the same direction as the inclination of a straight line or curve showing the bending moment distribution acting on the beam. For example, in Fig. 4, the bending moment distribution acting on the H-shaped steel perforated beam is shown by a straight line rising upward to the right from the left side to the right side of the photograph, and the straight line L also appears in the upward-right direction, the same as the bending moment distribution acting on the beam.

[0017] (First Embodiment) FIG. 5 is a view showing a reinforced H-shaped steel beam with holes according to the first embodiment of the present invention. FIG. 5 shows a view of a portion of an H-shaped steel beam 1 including a pair of flanges 11 and 12 and a web 13, as seen from the beam width direction, in which a through hole 2 is formed in the web 13, and a sectional view taken along line A-A thereof. In the present embodiment, a reinforcing member 31 is attached to the web 13 at a position adjacent to the through hole 2. The reinforcing member 31 includes two members separated from each other, and each of the two members is a flat steel plate including a cutout portion 311 cut out in a shape such that one corner of a rectangle having the length direction and the beam bending direction of the H-shaped steel beam 1 as sides is aligned with the through hole 2. The cutout portion 311 is arranged along the outer edge of the through hole 2. By attaching the two members of such a reinforcing member 31 on both sides of the through hole 2 in a region along the above-described straight line L, that is, a straight line inclined 45 degrees with respect to the material axis direction of the H-shaped steel beam 1 passing through the center of the through hole 2, buckling of the web 13 can be effectively suppressed.

[0018] More specifically, the reinforcing member 31 is arranged such that the corner 312 on the side opposite to the cutout portion 311 along the through hole 2 is located on the straight line L. At this time, by determining the long side length b and the short side length h of the reinforcing member 31 such that the diagonal angles 313 and 314 on both sides of the corner 312 contact or cross the parallel lines L1 and L2 of the straight line L that contact the outer edge of the through hole 2 (approximating the above-described elliptical arc C), buckling of the web 13 can be more effectively suppressed. The reinforcing member 31 may be attached only to one side of the web 13 as in the illustrated example, or may be attached to both sides of the web 13.

[0019] Note that the reinforcing member 31 is attached to the web 13 by, for example, fillet welding. However, it is not necessary for the entire circumference of the reinforcing member 31 to be welded to the web 13. For example, only two sides along the length direction of the H-shaped steel beam 1 or two sides along the beam deflection direction may be welded to the web 13. Further, together with these sides, the cutout portion 311 may be welded to the web 13 in a region along the through hole 2. The cutout portion 311 of the reinforcing member 31 may be aligned with the outer edge of the through hole 2, or may be slightly separated from the outer edge of the through hole 2, for example, to ensure a welding margin. In other examples, the reinforcing member 31 may be bolted to the web 13, and in this case, high-strength bolts may be used for the bolt connection.

[0020] The results of the analysis for verifying the effects of the first embodiment as described above will be further described. In the analysis, a reinforcing member was added to the same finite element numerical analysis model (diameter of the through hole φ = 300 mm, web plate thickness t w = 6 mm) as described above with reference to FIG. 1, and the same boundary conditions and material properties were applied. For the reinforcing member, based on the long side length b and short side length h (b = h = φ × √2 / 2 = 212 mm) when contacting the above-described parallel lines L1 and L2, three cases were set where the reinforcing member is smaller than the reference (b = h = 181 mm) and larger than the reference (b = h = 246 mm). Also, for the plate thickness t of the reinforcing member, three cases were set where the reinforcing member is thicker (t = 9 mm) and thinner (t = 3 mm) than the reference, with the case where it is equal to the web plate thickness (t = 6 mm) as the reference. The reinforcing member was assumed to be welded to the web over the entire circumference. The conditions regarding the reinforcing member in each case are shown in Table 2.

[0021]

Table 2

[0022] FIG. 6 is a graph showing the relationship between the long side length b and the short side length h of the reinforcing member and the full plastic strength Pp of the H-shaped steel perforated beam in the analysis for verifying the effects of the first embodiment, and FIG. 7 is a graph showing the relationship between the plate thickness t of the reinforcing member and the full plastic strength Pp of the H-shaped steel perforated beam. In each graph, the full plastic strength Pp is shown in a dimensionless manner by the calculated strength Qp when the member cross-section is in a fully plastic state. Also, in the graph of FIG. 6, the long side length b and the short side length h are shown as ratios with a reference value of φ×√2 / 2 taken as 1. From the graph of FIG. 6, it can be seen that when the long side length b and the short side length h of the reinforcing member are equal to or greater than the reference value of φ×√2 / 2, Pp / Qp exceeds 1, and the full plastic strength Pp of the H-shaped steel perforated beam exceeds the calculated strength Qp calculated by the conventional evaluation formula. Further, from the graph of FIG. 7, it can be seen that when the plate thickness t of the reinforcing member is equal to or greater than the web plate thickness, Pp / Qp exceeds 1, and the full plastic strength Pp of the H-shaped steel perforated beam exceeds the calculated strength Qp calculated by the conventional evaluation formula.

[0023] (Second Embodiment) FIG. 8 is a view showing a reinforced H-shaped steel perforated beam according to the second embodiment of the present invention. FIG. 8 shows a view of the portion where the through-hole 2 is formed in the web 13 of the H-shaped steel beam 1 including the flanges 11, 12 and the web 13 as seen from the beam width direction, and its cross-sectional view taken along line B-B. In the present embodiment, each of the two members constituting the reinforcing member 32 attached to the web 13 at a position adjacent to the through-hole 2 is a rectangular strip-shaped steel plate, and the long side 321 is arranged so as to intersect the above-described straight line L. Also, one long side 321 of the reinforcing member 32 is arranged so as to be adjacent to the outer edge of the through-hole 2. By attaching two rectangular strip-shaped members straddling the straight line L as the reinforcing member 32 to both sides of the through-hole 2, respectively, buckling of the web 13 can be effectively suppressed.

[0024] More specifically, regarding the reinforcing member 32, by determining the length b of the long side 321 such that the short side 322 contacts the parallel lines L1 and L2 of the straight line L that contacts the outer edge of the through hole 2, or exceeds these parallel lines L1 and L2, buckling of the web 13 can be more effectively suppressed. The reinforcing member 32 may be attached only to one side of the web 13 as in the illustrated example, or may be attached to both sides of the web 13.

[0025] Note that the reinforcing member 32 is attached to the web 13 using bolts 323 and nuts 324 as in the illustrated example, for example, but the number of bolts 323 and nuts 324 is not limited, and each member may be attached to the web 13 with more than two sets, three or more sets of bolts 323 and nuts 324 than the two sets shown in the figure. Also, high-strength bolts may be used for bolt joining. The long side 321 on the side of the through hole 2 in the reinforcing member 32 may contact the outer edge of the through hole 2, or may be slightly separated from the outer edge of the through hole 2 so as not to interfere with, for example, a pipe inserted through the through hole 2. In another example, the reinforcing member 32 may be fillet welded to the web 13, for example, over the entire circumference, along the long side 321, or along the short side 322.

[0026] The results of the analysis for verifying the effects of the second embodiment as described above will be further described. In the analysis, a reinforcing member was added to the same finite element numerical analysis model (through hole diameter φ = 300 mm, web plate thickness t w = 6 mm) described with reference to FIG. 1 above, and the same boundary conditions and material properties were applied. For the reinforcing member, three cases were set including two cases (b = 150 mm, 225 mm) where the reinforcing member is smaller than the reference, based on the long side length b (b = φ = 300 mm) when contacting the above-described parallel lines L1 and L2. Regarding the short side length h of the reinforcing member, it was set to 70 mm in all cases. Also, regarding the plate thickness t of the reinforcing member, three cases were set: a case where the reinforcing member is thicker (t = 9 mm) and a case where it is thinner (t = 3 mm) than the reference, with the case where it is equal to the web plate thickness (t = 6 mm) as the reference. The reinforcing member was assumed to be welded to the web over the entire circumference. The conditions regarding the reinforcing member in each case are shown in Table 3.

[0027]

Table 3

[0028] Figure 9 is a graph showing the relationship between the long side length b of the reinforcing member and the full plastic strength Pp of the H-shaped steel perforated beam in the analysis for verifying the effect of the second embodiment, and Figure 10 is a graph showing the relationship between the plate thickness t of the reinforcing member and the full plastic strength Pp of the H-shaped steel perforated beam. In each graph, the full plastic strength Pp is shown after being made dimensionless by the calculated strength Qp when the member cross-section is in a fully plastic state. Also, in the graph of Figure 9, the long side length b is shown as a ratio with the diameter φ of the through-hole being 1. From the graph of Figure 9, it can be seen that when the long side length b of the reinforcing member is equal to or greater than the diameter φ of the through-hole, Pp / Qp exceeds 1, and the full plastic strength Pp of the H-shaped steel perforated beam exceeds the calculated strength Qp calculated by the conventional evaluation formula. Also, from the graph of Figure 10, it can be seen that when the plate thickness t of the reinforcing member is equal to or greater than the web plate thickness, Pp / Qp exceeds 1, and the full plastic strength Pp of the H-shaped steel perforated beam exceeds the calculated strength Qp calculated by the conventional evaluation formula.

[0029] (Third Embodiment) Figure 11 is a view showing a reinforced H-shaped steel perforated beam according to the third embodiment of the present invention. Figure 11 shows a view of the portion where the through-hole 2 is formed in the web 13 of the H-shaped steel beam 1 including the flanges 11, 12 and the web 13 as seen from the beam width direction, and its C-C cross-sectional view. In the present embodiment, each of the two members constituting the reinforcing member 33 attached to the web 13 at a position adjacent to the through-hole 2 is an angle steel including a first surface and a second surface. The first surface is attached to the web 13 and is arranged such that the long side 331 intersects the above-described straight line L, and the second surface is arranged so as to rise from the long side 331 on the through-hole 2 side of the first surface. A rising portion 335 is formed by this second surface. By attaching two members straddling the straight line L to both sides of the through-hole 2 as the reinforcing member 33 and each member having a rising portion 335, the rigidity of the reinforcing member 33 is improved, and buckling of the web 13 can be more effectively suppressed.

[0030] More specifically, with respect to the reinforcing member 33, the length b of the long side 331 of the first surface is determined such that the short side 332 of the first surface of the angle steel contacts or crosses the parallel lines L1 and L2 of the straight line L that the short side contacts the outer edge of the through hole 2, whereby buckling of the web 13 can be more effectively suppressed. The reinforcing member 33 may be attached only to one side of the web 13 as in the illustrated example, or may be attached to both sides of the web 13.

[0031] Note that the reinforcing member 33 is attached to the web 13 using bolts 333 and nuts 334 as in the illustrated example, but the number of bolts 333 and nuts 334 is not limited, and each member may be attached to the web 13 with more than two sets, three or more sets of bolts 333 and nuts 334 than the two sets shown. Also, high-strength bolts may be used for bolt connection. The long side 331 on the side of the through hole 2 on the first surface of the reinforcing member 33 may contact the outer edge of the through hole 2, or may be slightly separated from the outer edge of the through hole 2 so as not to interfere with, for example, a pipe inserted into the through hole 2. In another example, the reinforcing member 33 may be fillet welded to the web 13 along the entire circumference, long side 331, or short side 332 of the first surface.

[0032] Regarding the results of the analysis for verifying the effects of the third embodiment as described above, further explanation will be given. In the analysis, the same finite element numerical analysis model as that described above with reference to FIG. 1 (diameter of the through hole φ = 300 mm, thickness of the web plate t wAfter adding a reinforcing member of angle steel with a height of 6 mm, the same boundary conditions and material properties were applied. For the reinforcing member, based on the long side length b = 300 mm and short side length h = 70 mm when contacting the above-mentioned parallel lines L1 and L2, five cases with rising heights r = 25 mm, 50 mm, 70 mm, 100 mm, and 125 mm were set. Also, for the plate thickness t of the reinforcing member, with the rising height r = 70 mm, three cases were set based on the case where it is equal to the web plate thickness (t = 6 mm), namely the case where the plate thickness of the reinforcing member is thicker than the reference (t = 9 mm) and the case where it is thinner than the reference (t = 3 mm). The reinforcing member was welded to the web around the entire circumference of the first surface of the angle steel. The conditions regarding the reinforcing member in each case are shown in Table 4.

[0033]

Table 4

[0034] Figure 12 is a graph showing the relationship between the rising height r of the reinforcing member and the full plastic strength Pp of the H-shaped steel perforated beam in the analysis for verifying the effect of the third embodiment, and Figure 13 is a graph showing the relationship between the plate thickness t of the reinforcing member and the full plastic strength Pp of the H-shaped steel perforated beam. In each graph, the full plastic strength Pp is shown after being made dimensionless by the calculated strength Qp when the member cross-section is in a fully plastic state. From the graph in Figure 12, it can be seen that regardless of the rising height r, Pp / Qp exceeds 1, and the full plastic strength Pp of the H-shaped steel perforated beam exceeds the calculated strength Qp calculated by the previous evaluation formula. Therefore, although the rising height r in the reinforcing member is not particularly limited, it is convenient to form the reinforcing member with equal-angle steel and make the rising height r the same as the short side length h. Also, from the graph in Figure 10, when the rising height r of the reinforcing member is about the same as the short side length h, it can be seen that even if the plate thickness t of the reinforcing member is smaller than the web plate thickness, Pp / Qp exceeds 1, and the full plastic strength Pp of the H-shaped steel perforated beam exceeds the calculated strength Qp calculated by the previous evaluation formula. As already mentioned, in the case of the angle steel reinforcing member, due to the presence of the rising part, the rigidity is improved, so sufficient reinforcement may be possible even with a thinner plate thickness.

[0035] (Required Plate Thickness of Reinforcement Member) Hereinafter, the required plate thickness t of the reinforcement member for effectively reinforcing the periphery of the through-hole will be further considered. Equations (1) and (2) are equations for calculating the required plate thickness t of the reinforcement member req from the required value D of the web width-to-thickness ratio (beam depth / web plate thickness) of the H-shaped steel perforated beam, the beam depth H, the web plate thickness t req , the plate thickness correction coefficient α for the reinforcement member req , and the overall correction coefficient β. As described above with reference to FIGS. 1 to 3, since the decrease in the member strength of the perforated beam is more significant in the range where the web width-to-thickness ratio is generally 50 or more, the required value D of the web width-to-thickness ratio w is arranged using 50, but the web width-to-thickness ratio D n is not limited to this range. req is not limited to this range. req is not limited to this range.

Number

[0036] In the above equation (1), the plate thickness correction coefficient α w is used to reflect the plate thickness of the reinforcement member joined only to a part of the web in the web plate thickness t n . The plate thickness correction coefficient α n is set based on the ratio of the plate thickness when the volume of the reinforcement member is evenly distributed in the region S on the flange side as shown in FIG. 14 (in the case of the first embodiment) and FIG. 15 (in the case of the second and third embodiments) to the web plate thickness.

[0037] The plate thickness correction coefficient α1 in the case of the first embodiment is obtained by the following equations (2) to (5). In these equations, A pl1 is the area of the reinforcement member, A w1 is the area of the region S for evenly distributing the reinforcement member, t f is the flange plate thickness of the H-shaped steel beam, b is the width of the reinforcement member, h is the height of the reinforcement member, φ is the diameter of the through-hole, and R is the opening ratio. The equation (5) for obtaining the opening ratio R is also used in the calculation of the plate thickness correction coefficient of other embodiments.

[0038]

Number

[0039] In the case of the second embodiment, the plate thickness correction coefficient α2 is obtained by the following formulas (6) to (8). In these formulas, A pl2 is the area of the reinforcing member, A w2 is the area of the region S for leveling the reinforcing member, b is the length of the long side of the reinforcing member, and h is the length of the short side of the reinforcing member.

[0040]

Equation

[0041] In the case of the third embodiment, the plate thickness correction coefficient α3 is obtained by the following formulas (9) to (11). In these formulas, A pl3 is the area of the reinforcing member (including the first and second surfaces of the channel steel), A w3 is the area of the region S for leveling the reinforcing member, b is the length of the long side of the first surface of the channel steel, and h is the length of the short side of the first surface of the channel steel.

[0042]

Equation

[0043] Also, in the above formula (1), the correction coefficient β is the overall correction coefficient, and it can be determined by comparing the value on the right side of formula (1) with the analysis result. Specifically, in the analysis for verifying the effects of the first and second embodiments described above, it was shown that when the plate thickness of the reinforcing member is 6 mm or more than the web plate thickness t w = 6 mm, the full plastic load-bearing capacity of the H-shaped steel perforated beam exceeds the calculated load-bearing capacity calculated by the previous evaluation formula. In these examples, when the web depth-to-thickness ratio D req = 50, the value on the right side of formula (1) with β = 1 is 9.2 mm. On the other hand, since the required plate thickness t req estimated from the analysis result is 6 mm or more, the result will be consistent if the correction coefficient β = 6 / 9.2 = 0.65. For each of the first to third embodiments described above, the required plate thickness t calculated using formula (1) from the dimensions of each partreq The minimum values are shown in Tables 5 to 7. The web width-to-thickness ratio D req is in the range of 60 to 120, and it can be seen that the required plate thickness t of the reinforcing member req is 2 mm to 7 mm.

[0044]

Table 5

[0045]

Table 6

[0046]

Table 7

Explanation of Symbols

[0047] 1…H-shaped steel beam, 11, 12…flanges, 13…web, 2…through hole, 31, 32, 33…reinforcing members, 311…cut-out part, 321, 331…long sides, 322, 332…short sides, 323, 333…bolts, 324, 334…nuts, 335…rising part.

Claims

1. In an H-shaped steel beam including a pair of flanges and a web, a reinforced H-shaped perforated steel beam in which a through-hole is formed in the web and a reinforcing member is attached to the web at a position adjacent to the through-hole, wherein the reinforcing member includes two members separated from each other, and the two members are attached to both sides of the through-hole in a region along a straight line that passes through the center of the through-hole and is inclined 45 degrees with respect to the material axis direction of the H-shaped steel beam. Reinforced H-shaped perforated steel beam.

2. Each of the two members is a steel plate having a planar shape in which one corner of a rectangle is cut out to match the through-hole, and the cut-out portion is arranged along the outer edge of the through-hole. The reinforced H-shaped perforated steel beam according to claim 1.

3. Each of the two members is a rectangular strip-shaped steel plate, and the long side intersects the straight line and one of the long sides is arranged adjacent to the outer edge of the through-hole. The reinforced H-shaped perforated steel beam according to claim 1.

4. Each of the two members is a channel steel including a first surface and a second surface, the first surface is attached to the web and the long side of the first surface intersects the straight line, and the second surface is arranged to rise from the long side of the first surface on the through-hole side. The reinforced H-shaped perforated steel beam according to claim 1.

5. The reinforcing member is arranged to be in contact with or cross over a parallel line of the straight line in contact with the outer edge of the through-hole. The reinforced H-shaped perforated steel beam according to any one of claims 1 to 4.

6. The reinforcing member is welded to the web. The reinforced H-shaped perforated steel beam according to any one of claims 1 to 4.

7. The reinforcing member is bolted to the web. The reinforced H-shaped perforated steel beam according to any one of claims 1 to 4.

8. High-strength bolts are used for the bolt connection. The reinforced H-shaped perforated steel beam according to claim 7.

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