Square steel pipe column reinforcement structure

Abstract

To provide a square steel pipe column reinforcing structure capable of improving the performance of a square steel pipe column with simple structure and weight-suppressed structure.SOLUTION: In a square steel pipe column reinforcing structure 100, by appropriately selecting the size of a reinforcing material according to a square steel pipe column 1 to be reinforced, the local buckling of the square steel pipe column 1 is allowed, but the buckling deformation is moderately restrained so that the decrease in yield strength after the local buckling can be moderated, and the deformation performance can be improved. Further, by limiting the reinforcement to the end part of the square steel pipe column 1 where the local buckling may occur, a significant increase in the number of processes can be avoided. In addition, by attaching a reinforcing member 20 at a predetermined interval from the end surface of the square steel pipe column 1 in the longitudinal direction, it is possible to prevent an excessive increase in the yield strength of the square steel pipe column 1 which may affect the design of a peripheral member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a square steel pipe column reinforcement structure. [Background technology]

[0002] The seismic performance of a building is evaluated based on the strength and deformation capacity of its constituent members. When a square steel pipe column has a large width-to-thickness ratio (outer diameter / plate thickness), local buckling occurs at the end of the column when subjected to external force, resulting in a premature loss of strength and poor deformation capacity, which becomes a problem. In response to this, architectural design involves verifying safety by increasing the design external force according to the width-to-thickness ratio of the square steel pipe column. Meanwhile, in order to improve the seismic performance of square steel pipe columns, construction methods have been proposed to improve the strength or deformation capacity of the columns, and most of these methods are aimed at improving strength.

[0003] To improve the strength or deformation capacity of square steel pipe columns, reinforcement structures are sometimes used, such as placing reinforcing materials at the column ends. For example, methods such as rib plate reinforcement and cover plate reinforcement are sometimes used to improve the strength of square steel pipe columns. The latter method, for example, is summarized as a seismic retrofitting method for existing buildings in the "2018 Cold-Formed Square Steel Pipe Design and Construction Manual Supplement: STKR Column Reinforcement Design and Construction Manual" published by the Building Center of Japan.

[0004] Patent Document 1 describes a known reinforcement method for improving the deformation capacity of square steel pipe columns. Patent Document 1 describes a structure for improving the deformation capacity of square steel pipe columns, in which a reinforcing member is placed through a gap on at least one side of the outer or inner surface of the end of the square steel pipe column, so that when the square steel pipe column experiences local buckling deformation, the reinforcing member abuts against the end of the column, thereby restricting the local buckling deformation. Alternatively, as a repair method for restoring the strength of damaged square steel pipe columns, the Japan Building Disaster Prevention Association's "Damage Classification Criteria and Restoration Technical Guidelines for Earthquake-Damaged Buildings, etc. (2015)" describes a method for restoring the strength of square steel pipe columns damaged by earthquakes by welding cover plates to the outside of the columns where local buckling deformation has occurred, thereby restoring the strength to the same level as the original steel pipe. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-136929 Summary of the Invention [Problem to be solved by the invention]

[0006] Here, square steel pipe columns with a large width-thickness ratio suffer from the problem of poor deformation performance because they lose their strength quickly when subjected to external forces. Furthermore, many conventional reinforcement methods for square steel pipe columns are primarily aimed at improving strength, and excessive strength improvement can have a negative impact on the design of surrounding components. When reinforcing columns, the fit between the reinforcing material and the wall material can be problematic. Construction methods with complex structures can also result in a significant increase in labor hours.

[0007] The present invention has been made to solve these problems, and aims to provide a square steel pipe column reinforcing structure that is simple in structure and lightweight, and can improve the performance of square steel pipe columns. [Means for solving the problem]

[0008] The square steel pipe column reinforcement structure of the present invention comprises a square steel pipe column and a plate-shaped reinforcing member provided on at least one of the outer surface and inner surface of the side wall portion of the square steel pipe column at a position spaced apart from the longitudinal end face of the square steel pipe column, wherein the diameter of the square steel pipe column is D, the plate thickness of the square steel pipe column is t, and the reinforcing length from the end face to the end of the reinforcing member is h. r and the thickness of the reinforcement material is t r In this case, (h r / D ≧ 0.6) and the relationship of formula (1) hold.

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[0009] In this square steel pipe column structure, by selecting an appropriate reinforcement size according to the square steel pipe column to be reinforced, local buckling of the square steel pipe column is permitted, but the buckling deformation is moderately restrained, thereby easing the decrease in strength after local buckling and improving deformation performance. Also, by limiting reinforcement to the ends of the square steel pipe column where local buckling may occur, a significant increase in labor costs can be avoided. Furthermore, by attaching the reinforcement at a certain distance from the longitudinal end face of the square steel pipe column, excessive increases in the strength of the square steel pipe column that would affect the design of surrounding components can be prevented. Because the reinforcement has a plate-like structure, the amount of protrusion of the reinforcement from the surface of the square steel pipe column is small, thereby reducing the impact on the interface with the wall material. Also, (h r By satisfying the relationship (R / D ≧ 0.6), the required performance of a square steel pipe column can be ensured by ensuring a sufficient reinforcement length. In addition, since the relationship of formula (1) holds, excessive weight increases can be suppressed. As a result, the performance of a square steel pipe column can be improved with a simple structure that is also weight-reduced.

[0010] In a structure reinforced with square steel pipe columns, (h r / D ≧ 0.8) can be established. In this case, the performance required for square steel pipe columns can be further ensured.

[0011] In a structure reinforced by square steel pipe columns, (t r / t ≧ 0.26) can be established. In this case, the performance required for square steel pipe columns can be further ensured.

[0012] In a structure reinforced with square steel pipe columns, the relationship in formula (2) may be satisfied. In this case, excessive weight increase can be further suppressed.

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[0013] The square steel pipe column reinforcement structure comprises a square steel pipe column and a plate-shaped reinforcement member provided on at least one of the outer surface and inner surface of the side wall portion of the square steel pipe column at a position spaced apart from the end face in the longitudinal direction of the square steel pipe column, where the diameter of the square steel pipe column is D and the reinforcement length from the end face to the end of the reinforcement member is h r In this case, (h r / D ≧ 0.6) and the relationship (weight increase rate = (reinforcement weight) / (square steel pipe column weight) ≦ 0.08) hold.

[0014] In this type of square steel pipe column, by selecting an appropriate reinforcement size according to the square steel pipe column to be reinforced, local buckling of the square steel pipe column is permitted, but the buckling deformation is moderately restrained, thereby easing the decrease in strength after local buckling and improving deformation performance. Also, by limiting reinforcement to the ends of the square steel pipe column where local buckling may occur, a significant increase in labor costs can be avoided. Furthermore, by attaching the reinforcement at a certain distance from the longitudinal end face of the square steel pipe column, an excessive increase in strength of the square steel pipe column that would affect the design of surrounding components can be prevented. Because the reinforcement has a plate-like structure, the amount of protrusion of the reinforcement from the surface of the square steel pipe column is small, thereby reducing the impact on the interface with the wall material. Also, (h r By satisfying the relationship (weight increase rate = (reinforcement weight) / (square steel pipe column weight) ≦ 0.08), the required performance of a square steel pipe column can be ensured by ensuring sufficient reinforcement length. In addition, the relationship (weight increase rate = (reinforcement weight) / (square steel pipe column weight) ≦ 0.08) holds true, so excessive weight increase can be suppressed. As a result, the performance of a square steel pipe column can be improved with a simple structure that keeps weight down. [Effects of the Invention]

[0015] According to the present invention, the performance of a square steel pipe column can be improved with a simple structure and a reduced weight. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing a column-beam joint structure 50 employing a square steel pipe column reinforcing structure 100 according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing the entire square steel pipe column 1. [Figure 3] FIG. 1 is a diagram showing a square steel pipe column reinforcement structure. [Figure 4] FIG. [Figure 5] 1 is a table showing a list of test specifications and test results. [Figure 6] 10 is a graph showing test results. [Figure 7] FIG. 1 is a diagram illustrating an outline of an analytical model. [Figure 8] 10 is a graph showing the analysis results. [Figure 9] FIG. 10 is a diagram showing a modified form of the analysis result. [Figure 10] 10 is a graph showing the analysis results. [Figure 11] FIG. 10 is a diagram showing the effective range of reinforcement specifications for a square steel pipe column reinforced structure. [Figure 12] FIG. 10 is a diagram showing a reinforcing member of a square steel pipe column reinforcing structure according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[0018] Fig. 1 is a perspective view showing a column-beam connection structure 50 in which a square steel pipe column reinforced structure 100 according to an embodiment of the present invention is adopted. Fig. 2 is a view showing the entirety of a square steel pipe column 1. As shown in Figs. 1 and 2, the column-beam connection structure 50 comprises a square steel pipe column 1, a beam 2 joined to the square steel pipe column 1, and a joint core 3. Note that Figs. 1 and 2 merely show one example of an application of the square steel pipe column reinforced structure, and the application can be changed as appropriate.

[0019] The square steel pipe column 1 is made of a steel pipe with a rectangular cross section. The upper square steel pipe column 1 and the lower square steel pipe column 1 are connected to each other in the vertical direction via a connecting core 3. The square steel pipe column 1 has four side wall portions 10. The square steel pipe column 1 has a lower end face 1a and an upper end face 1b in the longitudinal direction (vertical direction).

[0020] The beams 2 on all four sides are connected to the square steel pipe columns 1 via connecting cores 3. The beams 2 have an H-shaped cross section and include upper and lower flanges 2a, 2b and a web portion 2c that connects the flanges 2a, 2b together.

[0021] The joint core 3 includes a steel pipe section 3a having a rectangular cross section, and diaphragms 3b, 3c formed on the upper and lower end faces of the steel pipe section 3a. The lower end face 1a of the upper square steel pipe column 1 is joined to the diaphragm 3b of the joint core 3. The upper end face 1b of the lower square steel pipe column 1 is connected to the diaphragm 3c of the joint core 3. In addition, the upper and lower flanges 2a, 2b of the beam 2 are also joined at the positions of the upper and lower diaphragms 3b, 3c.

[0022] The square steel pipe column reinforcement structure 100 includes the above-mentioned square steel pipe column 1 and a plurality of reinforcing members 20. The reinforcing members 20 are rectangular plate-like members provided on at least one of the outer and inner surfaces of the side wall portions 10 of the square steel pipe column 1 at positions spaced apart from the end faces 1a, 1b of the square steel pipe column 1. In this embodiment, the reinforcing members 20 are formed in a rectangular shape and fixed to the outer surfaces of the side wall portions 10. The reinforcing members 20 are provided near the lower end face 1a of the square steel pipe column 1 for all of the four side wall portions 10. The reinforcing members 20 are provided near the upper end face 1b of the square steel pipe column 1 for all of the four side wall portions 10. Therefore, a total of eight reinforcing members 20 are provided for one square steel pipe column 1.

[0023] Next, the dimensional relationship of the square steel pipe column reinforcement structure 100 will be explained with reference to Fig. 3. Note that Fig. 3 shows the configuration of the lower side of the square steel pipe column 1, but the upper side has a similar configuration. As shown in Fig. 3(a), the diameter of the square steel pipe column 1 is D. The plate thickness of the square steel pipe column 1 is t. As shown in Fig. 3(b), the reinforcement length from the lower end face 1a of the square steel pipe column 1 to the end 20a of the reinforcing member 20 on the side away from the end face 1a is h. r The gap between the lower end face 1a of the square steel pipe column 1 and the end 20b of the reinforcing member 20 close to the end face 1a is defined as S r The end portions 20a and 20b are parallel to the end face 1a of the square steel pipe column 1. The width of the reinforcing member 20 is b r The reinforcing member 20 is disposed at the center of the side wall portion 10 in the width direction. The opposite ends 20c and 20d of the reinforcing member 20 in the width direction are spaced inward from the opposite ends 10a and 10b of the side wall portion 10 in the width direction and are parallel to the opposite ends 10a and 10b. The plate thickness of the reinforcing member 20 is t r The length of the square steel pipe column 1 is L. Specifically, the "diameter D x thickness t of the square steel pipe column" may be in the range of "□200×6 to □550×19" for cold roll-formed square steel pipes, and "□350×12 to □1000×32" for cold press-formed square steel pipes. The range of the reinforcing material thickness is "0.26≦t r / t≦1.0". The range of reinforcement length is "0.6≦h r / D≦2.0". The width of the reinforcement material is "0 r / D≦0.8". The gap is "0≦S r / D≦0.27".

[0024] Next, the setting of the preferable dimensional relationship of each part of the square steel pipe column reinforced structure 100 will be explained. First, with reference to Figs. 4 to 6, the test on the strength of the square steel pipe column reinforced structure 100 will be explained. Specifically, in order to confirm the reinforcing effect of the square steel pipe column reinforced structure 100, the plate thickness t r , reinforcement length h r A full-scale three-point bending test (monotonic / cyclic loading) was conducted with the variable σ. The test specimen shown in Figure 4(a) was prepared. Figure 4(b) shows an enlarged view of the area marked "A" in the figure. Two test specimens were prepared, each with a square steel pipe column 1 and reinforcement members 20 attached to all four sides. The end of each square steel pipe column 1 on the side where the reinforcement member 20 was attached was supported by a support member 32. The opposite end of each square steel pipe column 1 was supported by a support member 31. A load was applied to the central support member 32, and measurements were taken to observe the local buckling behavior. An "unreinforced" test specimen without reinforcement members 20 was also prepared.

[0025] Tests were conducted under two conditions: monotonic loading (where loads are applied monotonically) and cyclic loading (where loads are applied repeatedly). Figure 5 shows the test specifications and results. Figure 6(a) shows the test results for the load-deformation relationship under monotonic loading. Figure 6(b) shows the test results for the load-deformation relationship under cyclic loading. It was confirmed that the maximum strength of the reinforced specimens was equivalent to that of the unreinforced specimens, and that the strength was equivalent to that of the original square steel pipe column. Furthermore, the "2.3 x 360" reinforcement had the highest reinforcement effect, with deformation capacity 1.36 times that of the unreinforced specimen under monotonic loading and 1.60 times that of the unreinforced specimen under cyclic loading. In this case, the two specimens with the longest reinforcement length of 360 mm were encircled, while the specimen with the shortest reinforcement length of 240 mm was unencircled. It was confirmed that the encircled type was more effective in improving deformation capacity. The "encircling" type refers to a deformation mode in which the local buckling deformation of the square steel pipe column is restrained by the reinforcement material while the deformation progresses (see, for example, Figure 9(a)). The "non-encircling" type refers to a deformation mode in which the reinforcement length h from the end face of the square steel pipe column connected to the diaphragm to the end of the reinforcement material is​r This deformation mode is one in which local buckling occurs starting from the unreinforced portion beyond the end face of the diaphragm, and deformation progresses (see, for example, Figure 9(b)). Note that the gap type, which will be described later, is a deformation mode in which local buckling occurs starting from the gap Sr between the end face of the square steel pipe column connected to the diaphragm and the end of the reinforcement material close to said end face, and deformation progresses (see, for example, Figure 9(c)).

[0026] Next, analytical tests will be explained with reference to Figs. 7 to 10. Here, in order to confirm the effect of the construction method on the required performance of the square steel pipe column 1, a model capable of precisely reproducing the full-scale test results was constructed (Fig. 7 and Figs. 8(b) and (c)), and a parametric study on the plate thickness and reinforcing length of the reinforcement material 20 was then carried out by FEM analysis. Fig. 7 is a diagram showing an outline of the analytical model. Figs. 8(b) and (c) are graphs showing the results of a comparison between the full-scale test and the analytical results under the condition of "reinforcement 2.3 x 360". Fig. 8(b) shows the results of monotonic loading, and Fig. 8(c) shows the results of cyclic loading.

[0027] The analytical conditions are explained below. The conditions for the square steel pipe column were set as follows: "Width-thickness ratio D / t = 33.3", "Steel pipe used: BCR295", and "Shear span ratio L / 2D = 5". Rectangular SS400 steel was used as the reinforcing material. In addition, "Non-dimensional plate thickness t r / t" parameter, 0.13, 0.26, 0.36, 0.50, 0.67 (e.g., 300 × 9 / t r If / t=0.5, t r = 4.5 mm) was set. r / D" parameter can be set to 0.4, 0.6, 0.8, 1.0, 1.2 (e.g., 300 × 9 / h) r When / D=0.6, h r The width b is set to 240 mm. r =0.5D", "Gap S r = 0.2D" was fixed. The material data was set based on the results of full-scale material tests. The repeated loading history consisted of one loop of ±1δp, followed by two loops of ±2δp and ±4δp (see Figure 8(a)).

[0028] Figure 9 shows the deformation behavior of the analysis results for local buckling behavior (the figures in parentheses are roughly divided into thickness and length of reinforcement material). Figure 10(a) is a graph showing the results of comparing the load-deformation relationship between a non-reinforced model and a reinforced model. Figure 10(b) shows the relationship between the thickness and length of reinforcement plate and deformation capacity (cumulative plastic deformation magnification) E η A This is a graph showing the relationship between the width and thickness (D / t=33.3). In Figure 10(b), regarding "*1", "Structural Rank I" indicates the required cumulative plastic deformation ratio of columns as stated in the "Kouzai Club; Square Steel Pipe Design Research Group Report 1993". Regarding "*2", an analytical model with width-thickness ratios that are the boundaries of each member rank was created, and the reference values ​​derived from FEM analysis are shown.

[0029] As shown in Figure 9, the following three types of local buckling behavior were observed depending on the combination of non-dimensional plate thickness and reinforcement length. When the reinforcement length was short, the non-entrapment type behavior was observed as shown in Figure 9(b). Furthermore, as shown in Figure 10(b), when the reinforcement length was relatively long, the entrapment type behavior was observed as shown in Figure 9(a) or the gap type behavior as shown in Figure 9(c). If the plate thickness of the reinforcement material is the same, the reinforcement effect (cumulative plastic deformation magnification E η A ) has the following relationship: (a) Entrapment type or (c) Gap type > (b) Non-entrapment type. It was confirmed that even if the reinforcement length is increased beyond the reinforcement length at which the transition from (b) Non-entrapment type to (a) Entrapment type or (c) Gap type is first made, the reinforcement effect almost reaches a plateau.

[0030] From the above-mentioned tests and analyses, as shown in Fig. 11(a), the "non-dimensional reinforcement length h r / D” and “Nondimensional plate thickness t r In Fig. 11(b), the width-thickness ratio D / t = 33.3, the shear span ratio L / 2D = 5, and the reinforcement width b r / D=0.5" "Gap S rThe mapping was performed with a representative value of " / D=0.2." This map was created based on the performance evaluation and weight gain evaluation based on the analysis results shown in Figure 10(b). The weight gain is defined as "weight of reinforcement material = (weight of reinforcement material) / (weight of square steel pipe column)." When multiple reinforcements are used, the weight gain is the total weight of the reinforcements. Specifically, the darkest grayscale region E2 is the region classified as having a performance evaluation of "Structural Rank I (local buckling) or higher" and a weight gain of 6% or less. The next darkest grayscale region E3 is the region classified as having a performance evaluation of "Structural Rank I (local buckling) or higher" and a weight gain of 8% or less. The next darkest grayscale region E4 is the region classified as having a performance evaluation of "FA⇔FB boundary (reference) or higher" and a weight gain of 8% or less. Regions without grayscale are regions that do not meet either of these conditions. It is preferable that the parameters of the square steel pipe column reinforced structure 100 be set to conditions within area E1, which includes areas E2, E3, and E4.

[0031] Based on the above-mentioned mapping, the effective range of the reinforcement specifications for the square steel pipe column reinforced structure 100 was set. From the results of the above-mentioned mapping, in order to fall into the region E1, the "non-dimensional reinforcement length h r / D" must be 0.6 or more. Therefore, the effective range is (h r / D ≧ 0.6) is established. In order to fall into area E1, the weight increase rate must be 8% or less. Therefore, the relationship "Weight increase rate = (reinforcement weight) / (square steel pipe column weight)...(*)" can be expressed using each parameter as shown in equation (3). Equation (3) can be expressed as "width-thickness ratio D / t = 33.3", "shear span ratio L / 2D = 5", "reinforcement width b r / D=0.5" "Gap S rBy rearranging using " / D=0.2" and setting the effective range to "weight increase rate of 8% or less," the relationship in equation (4) is obtained. Note that although the value of the cross-sectional area A of the square steel pipe varies depending on the size, the figures are roughly similar even if the sizes are different, so after substituting the specific values ​​of D, t, and A, the same equation, i.e., equation (4), is obtained. By further rearranging this, equation (1) is obtained. Therefore, it is preferable that equation (1) holds true as the reinforcement specification for the square steel pipe column reinforced structure 100.

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[0032] 11(a), the region E2 is the most preferable, the region E3 is the next most preferable, and the region E4 is the next most preferable as the reinforcement specification of the square steel pipe column reinforced structure 100. Therefore, to be in the range of the region E2 or the region E3, (h r / D ≧ 0.8) is preferably satisfied. In addition, the relationship (t r / t ≧ 0.26) is preferably established. In addition, it is preferable that the weight increase rate of formula (4) is set to 6% or less so as to fall within the range of region E2, so that the following formula (2) is established.

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[0033] The operation and effect of the square steel pipe column reinforced structure 100 according to this embodiment will be described.

[0034] The square steel pipe column reinforcement structure 100 comprises a square steel pipe column 1 and a plate-like reinforcing member 20 provided on at least one of the outer surface and the inner surface of the side wall portion 10 of the square steel pipe column 1 at a position spaced apart from end faces 1a and 1b in the longitudinal direction of the square steel pipe column 1, where the diameter of the square steel pipe column 1 is D, the plate thickness of the square steel pipe column 1 is t, and the reinforcing length from the end face to the end 20a of the reinforcing member 20 is h. r The thickness of the reinforcement material 20 is t r In this case, (h r / D ≧ 0.6) and the relationship of formula (1) hold.

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[0035] In this square steel pipe column reinforcement structure 100, by selecting an appropriate reinforcement size according to the square steel pipe column 1 to be reinforced, local buckling of the square steel pipe column 1 is permitted, but the buckling deformation is moderately restrained, thereby easing the decrease in strength after local buckling and improving deformation performance. Also, by limiting reinforcement to the end of the square steel pipe column 1 where local buckling may occur, a significant increase in labor hours can be avoided. Also, by attaching the reinforcement 20 at a certain distance from the longitudinal end face of the square steel pipe column 1, an excessive increase in strength of the square steel pipe column 1 that would affect the design of surrounding components can be prevented. Because the reinforcement 20 has a plate-like structure, the amount of protrusion of the reinforcement 20 from the surface of the square steel pipe column 1 is small, thereby reducing the impact on the joint with the wall material. Also, (h r By satisfying the relationship (R / D ≧ 0.6), the reinforcement length is ensured sufficiently, thereby ensuring the performance required of the square steel pipe column 1. In addition, since the relationship of formula (1) holds, excessive increases in weight can be suppressed. As described above, the performance of the square steel pipe column 1 can be improved with a simple structure that is also weight-reduced.

[0036] In the square steel pipe column reinforced structure 100, (h r / D ≧ 0.8) can be established. In this case, the performance required for the square steel pipe column 1 can be further ensured.

[0037] In the square steel pipe column reinforced structure 100, (t r / t ≧ 0.26) can be established. In this case, the performance required for the square steel pipe column 1 can be further ensured.

[0038] The relationship of formula (2) may be established in the square steel pipe column reinforced structure 100. In this case, excessive increases in weight can be further suppressed.

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[0039] The square steel pipe column reinforcement structure 100 comprises a square steel pipe column 1 and a plate-shaped reinforcing member 20 provided on at least one of the outer surface and the inner surface of the side wall portion 10 of the square steel pipe column 1 at a position spaced apart from the end face in the longitudinal direction of the square steel pipe column 1, where the diameter of the square steel pipe column 1 is D and the reinforcing length from the end face to the end 20a of the reinforcing member 20 is h r In this case, (h r / D ≧ 0.6) and the relationship (weight increase rate = (reinforcement weight) / (square steel pipe column weight) ≦ 0.08) hold.

[0040] (h r By satisfying the relationship (weight increase rate = (reinforcement weight) / (square steel pipe column weight) ≦ 0.08), the required performance of the square steel pipe column 1 can be ensured by ensuring a sufficient reinforcement length. In addition, since the relationship (weight increase rate = (reinforcement weight) / (square steel pipe column weight) ≦ 0.08) holds, excessive weight increase can be suppressed. As a result, the performance of the square steel pipe column can be improved with a simple structure that suppresses weight.

[0041] The present invention is not limited to the above-described embodiments. The dimensions described in the above-described embodiments are merely examples, and may be changed as appropriate without departing from the spirit of the present invention.

[0042] For example, the shape of the reinforcing material 20 is not limited to the above-described embodiment. For example, the shape shown in Fig. 12 may be adopted. In Fig. 12, the reinforcing material 20 provided on one side wall portion 10 is divided into two pieces. Note that the number of divisions and the division method are not particularly limited. [Explanation of symbols]

[0043] 1...square steel pipe column, 10...side wall portion, 20...reinforcement material, 100...square steel pipe column reinforcement structure.

Claims

1. Square steel pipe column, a plate-shaped reinforcing member provided on at least the outer surface of the outer surface and the inner surface of the side wall portion of the square steel pipe column at a position spaced from the end face in the longitudinal direction of the square steel pipe column, The diameter of the square steel pipe column is D, The plate thickness of the square steel pipe column is t, The reinforcement length from the end face to the end of the reinforcing material is h ｒ year, The thickness of the reinforcing material is t ｒ In this case, (h ｒ / D ≧ 0.6) and the relationship of formula (1) are satisfied, The square steel pipe has a yield point or a lower limit of the proof stress of 295 N / mm ２ The width-thickness ratio D / t is 33.3, and the shear span ratio L / 2D is 5; The reinforcing material is a rectangular SS400 steel material with a width of b ｒ is 0.5D, and the gap S from the end face of the square steel pipe column to the reinforcing material ｒ is 0.2D, A square steel pipe column reinforcement structure in which the reinforcing material is fixed at the center position in the width direction on each of the four outer surfaces of the square steel pipe. [Equation 1]

2. (h ｒ 2. The square steel pipe column reinforced structure according to claim 1, wherein the relationship: / D ≧ 0.8) is satisfied.

3. (t ｒ 3. The square steel pipe column reinforced structure according to claim 1 or 2, wherein the relationship: / t ≧ 0.26) is satisfied.

4. The square steel pipe column reinforcement structure according to any one of claims 1 to 3, wherein the relationship of formula (2) holds. [Equation 2]

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