Cross Brace Mechanism for Two Joined Flat Steel Plates

Abstract

To minimize a visual field inhibition rate on a structure plane in aseismic reinforcement, and reduce the size and the weight of a component member so as to enable man-power construction in a building at a site where a heavy machine cannot be introduced.SOLUTION: Four flat steels 1 are arranged in a plane where the flat steels mutually approach, and end plates 2 having the same thicknesses as those of the flat steels 1 and having gradually increasing wide widths are integrated with both ends of the flat steels 1 by butt-welding 3. First flat steel 1a crosses second flat steel 1b in an X shape without contact, and third flat steel 1c and fourth flat steel 1d cross each other similar to the first flat steel 1a and the second flat steel 1b. Two gusset plates 4A and 4B have thicknesses equal to or less than those of the flat steels, and are welded to corners in a diagonal direction of a structure plane, the first flat steel 1a and the third flat steel 1c sandwich the gusset plates 4A and 4B, are rigidly fixed and integrated between both of the end plates 2 by a high strength bolt 6, to be formed into a first brace body 5A, and a second brace body 5B formed similarly to the first brace body 5A and the first brace body 5A form a cross brace body 10.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cross brace mechanism for double - combined flat steel plates. More specifically, it relates to a cross - type brace mechanism using flat steel for reinforcing a structural surface composed of columns and beams, and provides a brace reinforcement structure that can widen the view from a window provided in the structural surface.

Background Art

[0002] When seismic - reinforcing existing RC or SRC buildings, a structural surface R (for example, a ramen structure as shown in FIG. 10) composed of columns P and beams Q is reinforced by cross - braces 1 E1, 1 E2 . For this purpose, X - shaped braces disclosed in Patent Document 1 or V - shaped or K - shaped braces disclosed in Patent Document 2 are adopted. The pros and cons of these braces are also described in Non - Patent Document 1.

[0003] In summary, as brace materials, angle steel, flat steel, and H - shaped steel are used. FIGS. 10 and 11 show generally used braces. The X - shaped braces in FIGS. 10(a) and (b) resist only tensile stress, and the V - shaped brace in FIG. 11 is a type that resists both tensile and compressive forces.

[0004] The back - to - back angle - steel brace in FIG. 10(a) is the most common, but a large - area gusset plate 4E that greatly blocks the view is indispensable at the central intersection. In order to have a cross - sectional area that can exhibit the required tensile strength with a flat - steel brace, it is necessary to increase the width as shown in FIG. 10(b).

[0005] The H - shaped steel V - shaped brace is mainly used in large buildings and the like. When a horizontal force due to an earthquake acts, tensile stress is generated in one brace and compressive stress is generated in the other. Therefore, it is important that the member does not buckle. This is because if buckling occurs, a large unbalanced force is generated at the brace intersection, and the brace no longer functions. In order to make buckling less likely to occur, it is necessary to reduce the slenderness ratio. Therefore, the sectional radius of gyration needs to be increased, and in particular, a sufficiently large cross - sectional area in the direction perpendicular to the paper surface is required.

[0006] As a brace member of the steel frame structure as described above, generally, angle steel, flat steel, or H-shaped steel is used. However, with these, the area occupied in the cross-section of the brace is extremely large, and it tends to block the view from the window and gives a sense of oppression (see Fig. 3(b), Fig. 10, and Fig. 11). This is also significantly affected by the large high-strength bolt joints in the middle part of the brace and the large cross-sectional shapes of the reinforcing steel columns and reinforcing steel beams. Therefore, it is difficult to adopt in a cross-section where it is necessary to secure a wide view. In particular, when seismic reinforcement of an existing building is carried out, since the degree of design freedom is low, the tendency of narrowing of the view becomes remarkable. Especially in elementary and junior high school buildings, etc., for the sake of safety, a reinforcement design that inevitably narrows the view is forced.

[0007] However, in an office building, etc., a change that presents a significant reduction in the view and a remarkable sense of change in the appearance will lower the value of the building and is hardly allowed. Also, in a building facing a trunk road or a river, in many cases, an external scaffold cannot be installed, and there are also circumstances where heavy machinery cannot be used, so manual construction is inevitable. Therefore, it is important to enable reinforcement work from inside the building. Along with ensuring the view, miniaturization and weight reduction of the members for carrying in to the corresponding room are highly desired.

Prior Art Documents

Non-Patent Documents

[0008]

Non-Patent Document 1

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] The present invention has been made in view of the above circumstances, and its object is to minimize the visual obstruction rate in the floor plan during seismic reinforcement, while maintaining sufficient strength of the structural members and structurally sufficient joint strength, and to enable manual construction in buildings located in locations where heavy machinery cannot be introduced, by providing an intersecting brace mechanism for double-plate flat steel plates that can reduce the size and weight of the structural members.

Means for Solving the Problems

[0011] The present invention is applied to an intersecting brace mechanism using flat steel for reinforcing a floor plan R composed of columns P and beams Q. The features are as follows: referring to FIG. 1, four flat steels 1a, 1b, 1c, 1d having the same length and the same thickness are arranged in a vertical plane close to each other. End plates 2 with the same thickness and gradually increasing width as the flat steel, having narrow ends equal to the width of the flat steel, are integrated with both ends of the flat steel 1 by butt welding 3. The first flat steel 1a intersects without coming into X-shaped contact with the second flat steel 1b, and the third flat steel 1c arranged in the same posture as the first flat steel 1a intersects without coming into X-shaped contact with the fourth flat steel 1d arranged in the same posture as the second flat steel 1b. Two gusset plates 4A, 4B have a thickness less than that of the flat steel and are welded to the corners in the diagonal direction of the floor plan. The first flat steel 1a and the third flat steel 1c sandwich the first gusset plate 4A and the second gusset plate 4B and are rigidly fixed and integrated by high-strength bolts 6 between both end plates 2a1, 2c1, 2a2, 2c2 (see FIG. 2(a)), thus forming a first brace body 5A made of double flat steel. The other gusset plates 4C, 4D also have a thickness less than that of the flat steel and are welded to the corners in the other diagonal direction of the floor plan. The second flat steel 1b and the fourth flat steel 1d sandwich the third gusset plate 4C and the fourth gusset plate 4D and are rigidly fixed and integrated by high-strength bolts 6 between both end plates 2b1, 2d1, 2b2, 2d2, thus forming a second brace body 5B made of double flat steel. And the first brace body 5A and the second brace body 5B, both braces bodyA gusset plate is not provided at the intersection, and an intersection brace body 10 composed of two combined flat steel plates is formed. Further, as shown in FIG. 4, the gusset plate 4 is accompanied by a shim plate 7 for each of the facing end plates 2, and is integrated with not only the end plate 2 but also the shim plate 7 by high-strength bolts 6 so that the facing interval of the flat steel 1 of the brace body 5 can be made larger than the thickness of the gusset plate 4.

[0012] As shown in FIG. 6, the structural surface may be a lattice frame R1 composed of an H-shaped steel reinforcing column P1 and an H-shaped steel reinforcing beam Q1 integrated with the outer surfaces of an existing column P of RC or SRC construction E and an existing beam Q E .

[0013] As shown in FIG. 7, the structural surface is a lattice frame R2 composed of a channel-shaped steel reinforcing column P2 and a channel-shaped steel reinforcing beam Q2 integrated with the inside of an existing column P of RC or SRC construction E and an existing beam Q E , and it is preferable to arrange it in the surrounding space of the existing column P E · existing beam Q E .

[0014] Referring to FIGS. 8 and 9, the structural surface is a lattice frame R composed of a newly installed column P made of steel pipe such as H-shaped steel, square steel pipe, or round steel pipe N , and an H-shaped steel newly installed beam Q N , and the intersection brace body 10 is integrated with the inside of the newly installed column P N and the newly installed beam Q N , that is, it can be arranged in the surrounding space of the newly installed column P N · newly installed beam Q N . N

[0016] As shown in FIG. 5, a foamed plastic board 8 is adhered to the intersection part of the first brace body 5A and the second brace body 5B with a structural double-sided tape.

Effect of the Invention

[0017] The double - layer flat steel with half the width of a standard single - layer flat steel naturally generates a tensile strength equivalent to that of a single - layer flat steel brace. According to the present invention, while maintaining the required tensile strength as a brace, the visibility in the configuration where the cross - brace body 10 is applied is wider than that in the configuration where a single - layer flat steel brace is applied, and the sense of compression is eliminated (see Fig. 3(a)). In addition, the gusset plate is thinned to less than the distance between the facing surfaces of flat steel by twice the thickness of the shim plate. When the gusset plate is welded to the columns and beams of the structural surface, it can be easily welded without being accompanied by the difficulty of welding due to the thickness of the gusset plate.

[0018] The configuration consisting of H - shaped steel reinforcement columns and H - shaped steel reinforcement beams is a lattice frame, and since this is integrated on the outside of the existing columns and existing beams, the double - layer flat steel cross - brace mechanism reinforces the existing building from the outside. Therefore, the existing building can be reinforced while leaving the residents and office workers.

[0019] The configuration consisting of channel - shaped steel reinforcement columns and channel - shaped steel reinforcement beams is a lattice frame, and the construction of the cross - brace body can be carried out only from inside the existing building, eliminating the need for scaffolding, so construction can be carried out even on buildings facing roads or rivers.

[0020] The quality and quantity of steel used for the newly installed columns and newly installed beams are saved in the same way as mechanical processing and construction work, and a significant reduction in the cost of new construction is achieved.

[0022] The foamed plastic board does not make a rattling sound on the flat steel even if the flat steel vibrates inside the cross - brace body.

Brief Explanation of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0024] Hereinafter, the intersecting brace mechanism of two combined flat steel plates according to the present invention will be described in detail based on the drawings showing its embodiments. First, as shown in FIG. 1, a structure R composed of columns P and beams Q is reinforced by an intersecting brace mechanism using flat steel 1. This structure R is for reinforcement in an existing building that may be of RC construction or SRC construction, but can also be applied to the structure of a newly constructed building (see FIG. 9) described later.

[0025] The flat steel consists of four thin steel plates 1a, 1b, 1c, and 1d that are of the same length and thickness and are arranged in vertical planes close to each other. Each flat steel 1 is accompanied by end plates 2 with the same thickness but gradually increasing width, which are shown independently of the members in Fig. 2(a). It has narrow end portions equal to the width of the flat steel and is integrated at both ends of the flat steel 1 by butt welding 3 as shown in Fig. 2(b). The purpose of this end plate 2 is to ensure a large effective cross-sectional area for the arrangement of multiple rows of high-strength bolts 6, which will be described later, by gradually increasing the plate width.

[0026] As shown in Fig. 1, the first flat steel 1a and the second flat steel 1b intersect without contacting in an X shape, and the third flat steel 1c arranged in the same posture as the first flat steel 1a intersects the fourth flat steel 1d arranged in the same posture as the second flat steel 1b without contacting in an X shape.

[0027] The two gusset plates 4A and 4B have a thickness less than that of the flat steel and are welded at the corners in the diagonal direction of the structural plane R as shown by N P , N Q (see Fig. 2(b)). The first flat steel 1a and the third flat steel 1c sandwich the first gusset plate 4A and the second gusset plate 4B and are rigidly fixed and integrated by high-strength bolts 6 between both end plates 2a1, 2c1, 2a2, and 2c2 (also see Fig. 4 shown enlarged), thereby forming the first brace body 5A made of double flat steel.

[0028] The other gusset plates 4C and 4D also have a thickness less than that of the flat steel and are welded at the corners in the other diagonal direction of the structural plane. The second flat steel 1b and the fourth flat steel 1d sandwich the third gusset plate 4C and the fourth gusset plate 4D and are rigidly fixed and integrated by high-strength bolts 6 between both end plates 2b1, 2d1, 2b2, and 2d2, thereby forming the second brace body 5B made of double flat steel.

[0029] This first brace body 5A and the second brace body 5B, these two braces bodyA gusset plate is not provided at the intersection, that is, the intersection gusset plate 4E in Fig. 3(b) is not provided, and an intersection brace body 10 (see Fig. 1) composed of two joined flat steel plates is formed. The intersection is installed with a slight gap without being joined to each other. As a result, the complex interaction of tension and compression can be eliminated, and the entire brace length can be made the buckling length, so that those with a large slenderness ratio can be adopted.

[0030] Since the intersections are not joined, the slenderness ratio of the brace can be extremely large, such as 300 to 400 or more, and the buckling strength associated with compression becomes negligibly small. Therefore, the brace can be designed simply with only tensile stress. Incidentally, when the slenderness ratio is 350, the allowable compressive strength is extremely small, less than 5% of the allowable tensile strength.

[0031] Two flat steels stacked with half the width of a standard single flat steel naturally generate the same tensile strength as that of a single flat steel brace. Therefore, while maintaining the tensile strength required for the brace, the visibility in the configuration where the intersection brace body 10 is applied is wider than that in the configuration where a single flat steel brace is applied (see Fig. 3(b)), and there is no sense of oppression (see Fig. 3(a)). The end plate 2 with a gradually increasing width from the flat steel 1 enables the use of high-strength bolts, and the attachment to and the transfer of force to the gusset plate 4 become easy. That is, it results in maintaining sufficient strength of the component members and sufficient joining strength structurally. In addition, the component members can be downsized and lightened, and manual construction in buildings where heavy machinery cannot be introduced is realized. In any case, for the flat steel, one with a large plate thickness and a small width is selected to minimize the obstruction of visibility.

[0032] For example, high-tensile steel with a tensile strength of 490 MPa or more, such as 25×50 mm or 28×75 mm, is significantly different from ordinary flat steel braces that increase the width to reduce the thickness. The high-strength bolt friction joint of the brace and gusset plate per sheet is the opposite of the conventional method. By using one-sided friction joint, two braces can be joined. When viewed from the side of the high-strength bolts and gusset plates, it becomes two-sided friction, and the joining efficiency is the same as the conventional method. In the case of flat steel braces for transmitting large stresses, since the cross-section becomes large, two-sided friction joint using a splice plate is common. However, in the present invention, by dividing the brace into two, the required bearing friction force per side can be reduced.

[0033] Incidentally, as shown in FIG. 4, the gusset plate 4 is accompanied by a shim plate 7 for each facing end plate 2, and is integrated with not only the end plate 2 but also the shim plate 7 by high-strength bolts 6 so that the facing interval of the flat steel 1 of the brace body 5 can be made larger than the thickness of the gusset plate 4.

[0034] By doing so, the gusset plate 4 can be thinned to less than the facing interval of the flat steel 1 by twice the thickness of the shim plate 7. When the gusset plate is welded to the column P or beam Q having the structural surface R, it can be easily welded without the difficulty of welding caused by the thickness of the gusset plate 4.

[0035] Referring to FIG. 5(a), a foamed plastic board 8 is adhered to the intersection part of the first brace body 5A and the second brace body 5B by a structural double-sided tape 9.

[0036] This is because even if the flat steel vibrates in the cross brace body 10, the foamed plastic board 8 can be prevented from making a rattling sound on the flat steel 1. Note that the flat steel to which the foamed plastic board 8 is adhered may be either of FIGS. 5(b) and 5(c).

[0037] The above has described the basic aspects of the cross brace mechanism of the double-plate flat steel plate. The following shows a specific example for a building. Referring to Fig. 6, the structural plan can be a lattice frame R1 composed of an H-shaped steel reinforced column P1 and an H-shaped steel reinforced beam Q1 integrated on the outer surfaces of an existing column P E and an existing beam Q E . Incidentally, the reinforced column P1 of the lattice frame R1 is joined to the existing column P E through an indirect joint M1. The reinforced beam Q1 is welded to the reinforced column P1, and the lattice frame R1 is integrated into the existing structural plan composed of the existing column P E and the existing beam Q E . The indirect joint M1 is formed by covering the area where after-construction anchors, headed studs, and spiral bars are arranged with a formwork (not shown), and filling it with premix high-fluidity non-shrinking mortar, shrinkage-reducing filling mortar, and high-fluidity concrete.

[0038] Since the lattice frame R1 is integrated on the outside of the existing column P E and the existing beam Q E , the double-plate flat steel cross brace mechanism 10 reinforces the existing building from the outside. Therefore, the existing building can be reinforced while leaving the residents and office workers. Of course, as a result, the narrowing of the visual obstruction part described above, and sufficient bearing capacity of the structural members and structurally sufficient joint strength are maintained by the end plate 2. In addition, it goes without saying that the effects of miniaturization and weight reduction of the structural members are also exerted.

[0039] Fig. 7 shows an example of the case of a lattice frame R2 composed of a channel steel reinforced column P2 and a channel steel reinforced beam Q2 integrated inside an existing column P E and an existing beam Q E whose structural plan is of RC or SRC construction. That is, the lattice frame R2 is arranged in the surrounding space of the existing column P E ·existing beam Q E . Incidentally, M2 is an indirect joint. For the purpose of transporting the column P2 and beam Q2 of the lattice frame R2 in small parts, L-shaped parts R 2CR (refer to the shaded part in the figure) with metal-touch flange fastening are introduced at the corners of the lattice frame R2. As a result, the column P2 and beam Q2 have straight parts P2ST , Q 2ST is shortened as described above.

[0040] When the structural surface is the lattice frame R2 composed of the channel steel reinforced column P2 and the channel steel reinforced beam Q2, the construction of the cross brace body 10 can be carried out only from inside the existing building, and since scaffolding is not required, construction can be carried out even on buildings facing roads or rivers. Since the parts are miniaturized and lightened by the subdivision of the constituent members, the gusset plate welded L-shaped part R 2CR including can be carried in by the existing building elevator. In addition, it is often possible to use the pavement for a short time at night, and still the straight part P of the column P2 which is longer than other members 2ST and the straight part Q of the beam Q2 2ST and the flat steel 1 with the end plate 2 welded can be carried in through the window by a small crane.

[0041] As shown in Fig. 8, it is an example with the lattice frame R N , composed of the newly installed column P made of H-shaped steel N , and the newly installed beam Q made of H-shaped steel N as the structural surface. In many cases, braces are attached to the weak axis of the newly installed column P made of H-shaped steel N . The cross brace body 10 is integrated inside the newly installed column P N , and the newly installed beam Q N , that is, it is arranged in the surrounding space of the newly installed column P N , · newly installed beam Q N . The quality and quantity of the steel used for the newly installed column P N and the newly installed beam Q N are saved in the same way as machining and construction work, and a great reduction in the new construction cost is achieved.

[0042] Fig. 9(a) is an example also applied to a newly constructed building, where braces are attached to the strong axis of the H-shaped steel of the newly installed column P N . Only a horizontal sectional view is shown. Fig. 9(b) is also an example applied to a newly constructed building, where the newly installed column P N is made of steel pipes such as square steel pipes and round steel pipes. In this case also, only a horizontal sectional view is shown.

Explanation of Signs

[0043] 1: Flat steel, 1a: First flat steel, 1b: Second flat steel, 1c: Third flat steel, 1d: Fourth flat steel, 2, 2a1, 2a2, 2b1, 2b2, 2c1, 2c2, 2d1, 2d2: End plates, 3: Butt welding, 4: Gusset plate, 4A: First gusset plate, 4B: Second gusset plate, 4C: Third gusset plate, 4D: Fourth gusset plate, 5: Brace body, 5A: First brace body, 5B: Second brace body, 6: High-strength bolt, 7, 7 D1 , 7 D2 : Shim plate, 8, 8a1, 8c1, 8d1: Foamed plastic board, 9, 9a1, 9c1, 9d1: Structural double-sided tape, 10: Cross brace body, P: Column, P E : Existing column, P1: H-shaped steel reinforced column, P2: Channel steel reinforced column, P 2ST : Straight part, P N : Newly installed column made of H-shaped steel or steel pipe, Q: Beam, Q E : Existing beam, Q1: H-shaped steel reinforced beam, Q2: Channel steel reinforced beam, Q 2ST : Straight part, Q N : Newly installed H-shaped steel beam, M1: Indirect joint, M2: Indirect joint, R: Structural surface, R1: Lattice frame, R2: Lattice frame, R 2CR : L-shaped member, R N : Lattice frame.

Claims

1. In a cross bracing mechanism using flat steel for reinforcing a structure composed of columns and beams, four flat steels having the same length and the same thickness are arranged in a vertical plane approaching each other, end plates with the same thickness and gradually increasing width as the flat steel are integrated with both ends of the flat steel by butt welding with small-width ends equal to the width of the flat steel, the first flat steel intersects without contacting the second flat steel in an X shape, and the third flat steel arranged in the same posture as the first flat steel intersects without contacting the fourth flat steel arranged in the same posture as the second flat steel in an X shape, two gusset plates have a thickness less than that of the flat steel and are welded to the corners in the diagonal direction of the structure. The first flat steel and the third flat steel sandwich the first gusset plate and the second gusset plate and are rigidly fixed and integrated by high-strength bolts between both end plates, thereby forming a first brace body made of double flat steel steel, the other gusset plates also have a thickness less than that of the flat steel and are welded to the corners in the other diagonal direction of the structure. The second flat steel and the fourth flat steel sandwich the third gusset plate and the fourth gusset plate and are rigidly fixed and integrated by high-strength bolts between both end plates, thereby forming a second brace body made of double flat steel steel, the first brace body and the second brace body form an intersecting brace body composed of two-layer flat steel plates without providing a gusset plate at the intersection of the two brace bodies, the gusset plate is accompanied by a shim plate for each pair of facing end plates, and is integrated with not only the end plates but also the shim plate by the high-strength bolts, so that the facing interval of the flat steel of the brace body can be made larger than the thickness of the gusset plate. The intersecting brace mechanism of two-layer flat steel plates is characterized by this.

2. The structure is a lattice frame composed of H-shaped steel reinforcing columns and H-shaped steel reinforcing beams integrated with the outer surfaces of existing columns and existing beams of RC construction or SRC construction. The intersecting brace mechanism of two-layer flat steel plates according to Claim 1 is characterized by this.

3. The brace surface is a lattice frame composed of a channel steel reinforced column and a channel steel reinforced beam integrated inside the existing RC or SRC columns and existing beams, and is arranged in the surrounding space of the existing columns and existing beams. The intersecting brace mechanism of the double-layer flat steel plate according to claim 1, characterized in that.

4. The brace surface is a lattice frame composed of a newly installed steel column made of H-shaped steel or steel pipe such as square steel pipe or round steel pipe and a newly installed H-shaped steel beam. The intersecting brace body is integrated inside the newly installed column and the newly installed beam, that is, arranged in the surrounding space of the newly installed column and the newly installed beam. The intersecting brace mechanism of the double-layer flat steel plate according to claim 1, characterized in that.

5. At the intersecting part of the first brace body and the second brace body, a foamed plastic board is adhered by a structural double-sided tape. The intersecting brace mechanism of the double-layer flat steel plate according to claim 1, characterized in that.

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