Composite column

Abstract

To provide a composite column with high strength and high toughness.SOLUTION: A composite column 1 comprises a rectangular steel tube 10, a coating member 30 covering an outer peripheral side of the rectangular steel tube 10, and a wooden member 20 covering an outer peripheral side of the coating member 30. A clearance C extending along an axial direction is provided between the coating member 30 and the wooden member 20, and adhesive agents P to fill the clearance C are provided at prescribed positions of the clearance C. According to this invention, due to the provision of the clearance C between the rectangular steel tube 10 and the wooden member 20 in the composite column 1, and the provision of the adhesive agents P to the prescribed positions of this clearance C, a deformation state of the rectangular steel tube 10 is directly transferred to the wooden member 20, and thus integrity between the rectangular steel tube 10 and the wooden member 20 is improved and compressive strength of the composite column 1 is increased. Therefore, the composite column 1 with high strength and high toughness can be realized.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a composite column comprising a square steel pipe and a wooden member. [Background technology]

[0002] 2. Description of the Related Art Composite columns made by combining steel pipes and wooden members have been known in the past (see Patent Documents 1 and 2). Patent Document 1 shows an unbonded composite axial force member that includes a metal member and a piece of wood arranged in an unbonded state around the metal member. In this unbonded composite axial force member, both ends of the metal member protruding from the ends of the wood are used as inputs for the axial force. Patent Document 2 shows a composite column of steel pipes and wood materials, which comprises a square steel pipe subjected to axial compression and a wood material surrounding the pipe. Between the square steel pipe and the wood material, a damage suppression means is provided to reduce damage to the wood material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-27783 A [Patent Document 2] Patent No. 70333871 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a composite column with high strength and high toughness. [Means for solving the problem]

[0005] The inventors have developed a composite column comprising a square steel pipe and a wooden member by providing a predetermined gap along the axial direction between the square steel pipe and the wooden member and providing a gap filling means at a predetermined location of this predetermined gap, thereby directly transmitting the deformation state of the square steel pipe to the wooden member, allowing the wooden member to function efficiently as a stiffening material for the square steel pipe, and realizing a composite column with excellent strength and toughness. A composite column of the first invention (for example, composite column 1 described below) is a composite column comprising a square steel pipe (for example, square steel pipe 10 described below) and a wooden member (for example, wooden member 20 described below), characterized in that it comprises the square steel pipe and the wooden member covering the outer side surface of the square steel pipe, a predetermined gap (for example, clearance C described below) extending along the axial direction is provided between the square steel pipe and the wooden member, and gap filling means (for example, adhesive P described below) for filling the predetermined gap is provided at a predetermined location of the predetermined gap.

[0006] According to this invention, in a composite column comprising a square steel pipe and a wooden member, a predetermined gap is provided between the square steel pipe and the wooden member, and gap filling means is provided at a predetermined location of this gap, so that the deformation of the square steel pipe is directly transmitted to the wooden member, improving the unity between the square steel pipe and the wooden member and increasing the compressive strength of the composite column. Thus, a composite column with high strength and high toughness can be realized.

[0007] The composite column of the second invention is characterized in that a covering member (e.g., covering member 30 described below) is interposed between the square steel pipe and the wooden member, and the specified gap is provided between the square steel pipe and the covering member, or between the covering member and the wooden member.

[0008] According to this invention, when a predetermined gap is provided between the covering member and the wooden member, when an axial force acts on the square steel pipe, the square steel pipe and the covering member bend, and the outer peripheral side of the covering member abuts against the inner peripheral side of the wooden member. Then, the wooden member restrains the deformation of the square steel pipe, and the wooden member functions as a stiffener against the axial force acting on the square steel pipe. Thus, a composite column with high strength and high toughness can be realized. On the other hand, if a certain gap is provided between the square steel pipe and the covering member, when an axial force acts on the square steel pipe, the square steel pipe bends and the outer peripheral side of the square steel pipe abuts against the inner peripheral side of the covering member. Then, the covering member and the wooden member restrain the deformation of the square steel pipe, and the wooden member functions as a stiffener against the axial force acting on the square steel pipe. This makes it possible to realize a composite column with high strength and high toughness.

[0009] The composite column of the third invention is characterized in that the gap filling means is formed from any of adhesive, metal joints, calcium silicate boards, wood wool cement boards, hard wood chip cement boards, fiber reinforced cement boards, pulp cement boards, and gypsum boards.

[0010] According to this invention, the gap filling means is formed of any one of adhesives, metal joints, calcium silicate boards, wood wool cement boards, hard wood chip cement boards, fiber reinforced cement boards, pulp cement boards, and gypsum boards. Therefore, the gap filling means reliably fills the specified gaps, improving the unity between the square steel pipes and the wooden members and increasing the compressive strength of the composite column. In addition, if calcium silicate boards are used as a gap filling means, the fire resistance of the composite column can be improved.

[0011] The composite column of the fourth invention is characterized in that reinforcing metal fittings (e.g., screws 23 described below) are driven into the portion of the wooden member located on the end side of the square steel pipe from the outer surface of the wooden member toward the inside of the wooden member.

[0012] According to this invention, reinforcing metal fittings are driven from the outer surface of the wooden member toward the inside of the wooden member at the portion located on the end side of the square steel pipe, thereby improving the rigidity and bending deformation performance of the wooden member, and improving the strength and toughness of the composite column. Effect of the Invention

[0013] According to the present invention, a composite column with high strength and high toughness can be provided. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a longitudinal cross-sectional view of a composite pillar according to one embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of the composite column shown in FIG. 1 along line AA. [Diagram 3] FIG. 2 is a cross-sectional view of the composite pillar of FIG. 1 . [Figure 4] FIG. 13 is a diagram showing the behavior of a composite column when a vertical load acts on a square steel pipe. [Diagram 5] 1 is a flowchart showing a manufacturing procedure for a composite pillar. [Figure 6] This is an explanatory diagram of the manufacturing procedure for a composite column (Part 1: attaching a square steel pipe to a channel member). [Figure 7] This is an explanatory diagram of the manufacturing process for a composite column (part 2, attaching the fourth laminated board to the channel member). [Figure 8] FIG. 2 is a diagram showing the configuration of a test specimen used in a load test. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. 13 is a diagram showing characteristic values ​​of the steel material forming the test specimen square steel pipe. [Figure 12] FIG. 13 is a diagram showing characteristic values ​​of wood materials forming the wood members of the test specimens. [Figure 13] FIG. 13 is a cross-sectional view and an elevation view of a screw-reinforced test specimen. [Figure 14] This is an elevational view of a screw (Panellead S) used for screw reinforcement. [Figure 15] FIG. 13 is a diagram showing the relationship between screw reinforcement and splitting strength. [Figure 16] FIG. 13 is a diagram showing the test results (load-vertical displacement relationship) of the loading test. [Figure 17] FIG. 13 is a diagram showing the test results (load-horizontal displacement relationship) of the loading test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention is a composite column comprising a square steel pipe and a wooden member. In the composite column, a predetermined gap is provided between the square steel pipe and the wooden member along the axial direction, and a gap filling means is provided at a predetermined location of the predetermined gap. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a longitudinal sectional view of a composite column 1 according to one embodiment of the present invention. Fig. 2 is a sectional view of the composite column 1 of Fig. 1 taken along line AA. Fig. 3 is a sectional view of the composite column 1 of Fig. 1 taken along line BB. The composite column 1 is a column combining a square steel pipe 10 and a wooden member 20. The composite column 1 comprises a square steel pipe 10 that supports a vertical load, a covering member 30 that covers the outer circumferential side of the square steel pipe 10, and a rectangular frame-shaped wooden member 20 that covers the outer circumferential side of the covering member 30. In other words, the covering member 30 is interposed between the square steel pipe 10 and the wooden member 20. The square steel pipe 10 has four side surfaces 10A to 10D. The covering member 30 is made up of four calcium silicate plates 30A to 30D, and is provided on each of the four side surfaces 10A to 10D of the square steel pipe 10.

[0016] The wooden member 20 is constructed by joining four laminated lumber panels 20A-20D together in a square-shaped cross section, and the laminated panels 20A-20D are provided on each of the four side surfaces 10A-10D of the square steel pipe 10 and on the outside of the covering member 30. As shown in Fig. 3, screws 23 serving as reinforcing metal fittings are driven from the outer surface of the wooden member 20 toward the inside of the wooden member 20 in the portion of the wooden member 20 located on the end side of the square steel pipe 10. Between the covering member 30 and the wooden member 20, a clearance C is provided as a predetermined gap extending along the axial direction, and an adhesive P is applied to a predetermined location of this clearance C as a gap filling means for filling the clearance C. Specifically, the adhesive P is applied between each of the calcium silicate boards 30A-30D and each of the laminated boards 20A-20D.

[0017] FIG. 4 is a diagram showing the behavior of the composite column when a vertical load acts on the square steel pipe 10. When the clearance is small, as shown in Figure 4(a), when the square steel pipe 10 bends due to a vertical load, the square steel pipe (covering member) abuts against the wooden member 20 while the bending deformation of the square steel pipe is still small, and the bending deformation of the square steel pipe is restrained by this wooden member, so that the square steel pipe and the wooden member form a composite structure integrated together to resist the vertical load. In contrast, when the clearance is large, as shown in Figure 4(b), even if the square steel pipe bends due to a vertical load, if the bending deformation of the square steel pipe does not become large, the square steel pipe (covering member) will abut against the wooden member and the bending deformation of the square steel pipe will not be restrained, causing the square steel pipe to buckle early.

[0018] FIG. 5 is a flowchart showing the manufacturing procedure of the composite column 1. In step S1, as shown in FIG. 6, the square steel pipe 10 is laid on its side, and calcium silicate plates 30A to 30D are attached to the square steel pipe 10, so that the covering member 30 is integrated with the square steel pipe 10. In step S2, as shown in FIG. 6, three of the four laminated boards 20A to 20D constituting the wooden member 20, 20A to 20C, are joined together to form a channel member 21 having an open upper portion and a U-shaped cross section. In step S3, as shown in Fig. 6, adhesive P is applied to the inner wall surface of each of the assembled plates 20A-20C of the channel-shaped member 21. At this time, a washer 22 is placed on the inner bottom surface of the channel-shaped member 21. In this state, the square steel pipe 10 with the covering member 30 integrated therewith is lifted up and lowered from above the channel-shaped member 21 to be accommodated inside the channel-shaped member 21. In step S4, as shown in FIG. 7, adhesive P is applied to the upper surface of the covering member 30 housed inside the groove-shaped member 21, and adhesive (not shown) is also applied to the upper end surfaces of the laminated boards 20A and 20C of the groove-shaped member 21, and in this state, a fourth laminated board 20D is placed on top and attached.

[0019] [Load test] Three specimens of the above composite columns were fabricated and subjected to load tests. Specifically, knife edges were placed on both ends of the specimens to support them with pins, and the specimens were subjected to monotonous compressive load until they were destroyed. Fig. 8 is a diagram showing the configuration of the test specimen used in the load test. Fig. 9 is an elevation view of the test specimen. Fig. 10 is a cross-sectional view of the test specimen. Fig. 11 is a diagram showing characteristic values ​​of the steel material forming the square steel pipe of the test specimen. Fig. 12 is a diagram showing characteristic values ​​of the wood material forming the wooden member of the test specimen. Specimen No. 4 (Comparative Example 1) is a type in which neither adhesive nor screws are provided. Specimen No. 4' (Comparative Example 2) is a type in which only screws are provided. Specimen No. 4" (Example) is a type in which both adhesive and screws are provided. Specifically, the following settings were made for each test specimen. The square steel pipe was STKR400, □-75×75×4.5. The calcium silicate board was 20 mm thick. The laminated board that made up the wooden member was E95-F270 (equivalent) Japanese cypress.

[0020] When compressive axial force is applied to steel pipes in load tests, at the end of the bending deformation, the wooden members crack at their ends, and at that point the member reaches its strength. Therefore, screws were placed in the areas of the wooden member ends where cracks are expected to occur, improving the cracking strength and increasing the member strength. The length of the screws was selected so that the screws placed on both sides of the wood would overlap in the center, and three screws were placed for each expected crack surface, taking structural performance values ​​into consideration.

[0021] Figure 13 shows a cross-sectional view and an elevation of a test specimen reinforced with screws. Figure 14 shows an elevation of a screw (Panellead S) used for screw reinforcement. Specimen No. 4' and specimen No. 4" were reinforced with screws as shown in Figure 13. Figure 15 shows the relationship between screw reinforcement and splitting strength obtained from a durability experiment conducted separately. Figure 15 shows that by placing one screw per split surface at the end of the wooden member, the bending strength of the laminated timber can be expected to increase by 15.0 kN. Therefore, it was decided to place three Synegic long screws, "Panellead S" (Figure 14), per split surface. When considering the placement of the screws, it was noted that the screws should not be lined up in a straight line in the direction of the grain (to prevent splitting in the direction of the grain), that they should be located as close to the end (buttock surface) as possible (to prevent the progression of splitting), and that perpendicular screws should not interfere with each other.

[0022] In the test specimen, the clearance between the square steel pipe and the wooden member may affect the compressive strength. In other words, for the composite structure of the square steel pipe and the wooden member to be established and to exert the bending rigidity accumulation, the lateral deflection of the square steel pipe must be deformed more than the clearance between the two materials. When comparing the size of the clearance, if it is large, a larger deflection deformation is required for the composite structure to be established, and the ratio of the load increase to the deflection increase becomes smaller. If the compressive strength of the test specimen is determined by the splitting of the wooden member, the bending deformation that causes the splitting is reached early, so the compressive strength of the test specimen is expected to be low. On the other hand, if the clearance can be made smaller, it is assumed that the compressive strength of the member can be made larger. Therefore, the design clearance was set at 2.5 mm.

[0023] In addition, when fitting the square steel pipe into the channel member (wooden member), adhesive was applied to the position where the clearance between the two materials would exist, and the clearance between the two materials would be eliminated by hardening. Konishi's one-liquid urethane resin adhesive "KU928C-X" was adopted for the adhesive, taking into consideration its ease of acquisition, ease of application during specimen manufacturing, and the fact that it has the same hardness (Young's modulus) as the wooden members and calcium silicate boards after hardening. Although it is required that the bending deformation of the primary mode of the steel material is transmitted to the wooden members without being hindered by the clearance, it was decided that there was no need to fill the clearance with adhesive, so it was applied at intervals of approximately 300 mm. The amount of adhesive applied in one place was about 50 mm in diameter, and was piled up so that the thickness of the application was about 3 mm or more (set to be larger than the design clearance of 2.5 mm).

[0024] When fitting the square steel pipe with calcium silicate plates installed into the U-shaped channel member (step S3 above), adhesive is applied to the three inside surfaces of the laminated timber in advance, but a washer about 1.5 mm thick is placed on the bottom surface inside the channel member as a spacer. One washer is used for each adhesive location, and it is placed so that it partially overlaps the adhesive to prevent misalignment after the adhesive hardens. Washers are not placed on the two side surfaces.

[0025] When placing the fourth calcium silicate board on the top surface of the channel-shaped member (step S4), adhesive is applied to the top surface of the calcium silicate board in advance. The intervals and amount of adhesive applied are the same as those for the other three surfaces. No washers are placed.

[0026] Fig. 16 is a diagram showing the test results (load-vertical displacement relationship) of the load test, and Fig. 17 is a diagram showing the test results (load-horizontal displacement relationship) of the load test. The initial stiffness of each specimen matched the calculated axial stiffness, which was calculated by dividing the extension stiffness by the distance between supports. In addition, in specimen No. 4, the horizontal displacement (lateral deflection of the steel measured at the center of the member) increased from the early stage of loading, but in specimen No. 4'', it remained at approximately 0 mm until the load reached about 400 kN. After that, when the loading was continued, the slope of the load-horizontal displacement graph for specimen No. 4 recovered at a horizontal displacement of about 5 mm, suggesting that a composite structure of square steel pipes and wooden members had been formed. On the other hand, for specimen No. 4", a composite structure appears to have been formed from the early stages of loading, and no history similar to that of specimen No. 4 was observed.

[0027] With specimen No. 4", after reaching the maximum load of 468 kN, the square steel tube broke in a mode of breaking near the column head, and the load decreased. With specimen No. 4", no splitting occurred originating from the top or bottom ends of the wooden member. The maximum load of specimen No. 4 was 400 kN, which is 17.0% higher than the maximum load of specimen No. 4, demonstrating the effectiveness of the adhesive in eliminating clearance. Furthermore, in addition to "eliminating clearance with adhesive," specimen No. 4" also "reinforced the ends of the wooden components with screws." However, the horizontal displacement (lateral deflection) of the components was minute throughout the load, and almost no splitting stress due to bending deformation occurred at the ends of the wooden components. Therefore, it is believed that the same level of performance would be obtained even without "screw reinforcement."

[0028] According to this embodiment, the following effects are obtained. (1) In the composite column 1, a clearance C is provided between the square steel pipe 10 and the wooden member 20, and adhesive P is provided at a predetermined location of this clearance C, so that the deformation state of the square steel pipe 10 is directly transmitted to the wooden member 20, improving the unity between the square steel pipe 10 and the wooden member 20 and increasing the compressive strength of the composite column 1. Therefore, a composite column 1 with high strength and high toughness can be realized.

[0029] (2) Since the clearance C is filled with adhesive P, the integrity of the square steel pipe 10 and the wooden member 20 is improved, and the compressive strength of the composite column 1 is increased. (3) Reinforcing metal fittings are driven from the outer surface of the wooden member 20 toward the inside of the wooden member 20 at the portion located on the end side of the square steel pipe 10. This improves the rigidity and bending deformation performance of the wooden member 20, and improves the strength and toughness of the composite column 1.

[0030] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention. [Explanation of symbols]

[0031] P... Adhesive (gap filling means) C... Clearance (predetermined gap) 1... Composite column 10... Square steel pipe 10A... Side 10D... Side 20...Wood material 20A~20D...Laminated board 21... Channel-shaped member 22... Washer 23... Screw (reinforcement metal fitting) 30... Covering member 30A to 30D... Calcium silicate board

Claims

1. A composite column comprising a square steel pipe and a wooden member, The square steel pipe, The wooden member covers the outer peripheral side surface of the square steel pipe, A predetermined gap extending along the axial direction is provided between the square steel pipe and the wooden member, A composite pillar characterized in that a gap filling means for filling the specified gap is provided at a specified location of the specified gap.

2. A covering member is interposed between the square steel pipe and the wooden member, A composite column as described in claim 1, characterized in that the specified gap is provided between the square steel pipe and the covering member, or between the covering member and the wooden member.

3. A composite column as described in claim 1 or 2, characterized in that a reinforcing metal fitting is driven into the portion of the wooden member located on the end side of the square steel pipe from the outer surface of the wooden member toward the inside of the wooden member.

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