JP6587111B2 - Braces and brace mounting structure - Google Patents

Description

  The present invention relates to a steel brace used to reinforce a steel structure and its installation form, and more specifically, a brace that is excellent in compressive load and that allows easy adjustment of the overall length of the brace and allows the introduction of tension. It relates to the mounting structure.

  Conventionally, types of braces used for reinforcing steel structures include tensile braces, compression braces, and buckling-restrained braces. The tensile brace is an effective use of the advantages of steel materials, and even a steel material with a small cross section has a large resistance, and is therefore often used in small and medium-sized steel structures. On the other hand, the performance of a compression brace is determined based on the buckling strength of the brace body (steel material), but the joining member joined to the end of the brace body and the gusset plate on the steel frame side are joined. The buckling strength varies depending on the conditions (pin bonding or fixed bonding).

  10 (a) and 10 (b) are examples of the compression brace pin joint type, and respectively show a front view and a plan view. In this case, a bifurcated joint member 11 called a clevis is coupled to both ends of the circular steel pipe 10 used as the brace body, and an insertion hole on the gusset plate 12 side and an insertion hole 11a on the joint member 11 side are provided. By inserting the pin bolt 13 and screwing the nut 14 in the matched state, the gusset plate 12 is rotatably joined. FIG. 11 is an example of a compression brace fixed joining method using a circular steel pipe 10 in the brace body, and a cross-shaped joining member 15 having a plurality of insertion holes 15a joined to both ends of the circular steel pipe 10 and a gusset. The plate 16 is rigidly joined with a plurality of high strength bolts. This type of compression brace is used for seismic reinforcement of large buildings and existing buildings.

  Furthermore, the buckling-restrained brace has the features of both a tensile brace and a compression brace. A steel pipe called a buckling-restraining steel pipe is used as a means to prevent buckling of the tensile brace material (brace core material). By covering the outer periphery of the brace, it is structured to prevent a decrease in brace strength due to buckling of the brace core material.

By the way, in the compression brace and buckling restrained brace having the above-described configuration that bears the compression force, the following problems exist in terms of workability, productivity, reinforcement performance, and the like.
(1) In steel frame construction work, the workability is not very good because the dimensional accuracy varies between the brace mounting positions.
(2) Since fixed joints using high-strength bolts as shown in FIG. 11 require a large number of bolt insertion holes, the joint members and gusset plates tend to have variations in the dimensions between the insertion holes, resulting in reduced workability. Connected.
(3) Since the braces cannot be manufactured unless the original dimensions at the brace mounting position are confirmed, productivity is poor.
(4) Since the steel material itself is deformed or bent before being processed into the brace, the bending is not eliminated even after being processed into the brace.
(5) After the brace is attached, bending occurs due to the weight of the brace itself, and the brace is bent and cannot be corrected.
(6) The structure is difficult to cope with the manufacturing error of the brace itself, the manufacturing error of the gusset plate, and the error generated by welding.
(7) A brace that receives a compressive force is likely to be subjected to compression bending fracture, local buckling fracture, neck breakage, etc. at the end of the brace, particularly at the lower end.

  Of the above-mentioned problems, with regard to (1) to (3) in particular, a buckling-restrained brace that enables the length adjustment of the entire brace has been proposed (Patent Document 1).

Japanese Patent No. 5506744 (see FIGS. 1-3, paragraph 0032, etc.)

  The conventional buckling-restrained brace is linear (coaxial) by screwing the male threaded portions of a rod-shaped steel material having a smaller cross-sectional area into the female threaded portion of a pair of brace cores that are rod-shaped or tubular. The length of the entire brace is adjusted by rotating a rod-shaped steel material located in the middle. However, the rod-shaped steel material that connects the pair of brace cores is hidden inside the buckling restraint tube when both ends of the brace are joined to the gusset plate. It is difficult to eliminate deflection and introduce tension. For this reason, the above-described conventional buckling restrained brace has a problem that it is not effective for the above problems (4) to (6).

  The present invention was created to solve the above-described problems of the prior art, and can easily adjust the length of the entire brace, and can introduce tension even after installation, and its mounting structure. The purpose is to provide.

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application is directed to a joining member and brace body at an end joined to a gusset plate attached to a rectangular frame surface of a steel frame having a steel column and a steel beam as a framework. In the brace provided with an expansion / contraction portion between the bolt body, the expansion / contraction portion is screwed on one end side with respect to a bolt body in which right and left screws are formed on both sides of the hook-shaped protrusion, and left and right male thread portions of the bolt body. The other end side is screwed into both ends of the bolt body with a pair of cylindrical female screw members each coupled to the brace body and the joining member, and a projection on the inner peripheral surface engaged with the flange-like protrusion of the bolt body. was across the pair of cylindrical female screw member and a cylindrical member made of a steel tube to be fitted, the tubular a pair of cylindrical female screw member to rotate inside the bolt body by a rotational operation of the cylindrical member While sliding inside the member It is characterized in that employing the technical means that is close to or away from.

According to such a configuration, the telescopic portion provided between the joining member located at the end and the brace body located in the middle is fitted to the outside so as to straddle the pair of opposed cylindrical female screw members. When the joined cylindrical member ( circular steel pipe ) is rotated in an appropriate direction, the bolt main body inserted in the cylindrical member engages with the projection on the inner surface of the cylindrical member, and the hook-like projection is engaged. Are rotated in the same direction. A pair of cylindrical female screw members that are screwed to both sides of the hook-shaped protrusion at the center of the bolt body in a state where the brace body or the joining member is coupled to the other end side due to the rotation of the bolt body include a cylindrical member ( While being slid and moved inside the circular steel pipe), it is displaced in the direction of approaching or separating along the axis of the bolt body. Since a part of the brace can be expanded and contracted by such a rotation operation and the entire length can be easily adjusted, workability at the construction site is good. Further, after joining the joining member at the end of the brace to the gusset plate and installing the brace at a predetermined position, the cylindrical member of the expansion / contraction part is rotated in an appropriate direction, thereby bringing the pair of cylindrical female screw members close to each other The tension can be reliably introduced into the brace body.

  As another configuration of the brace according to the present invention, the expansion and contraction portion in the above configuration is a form in which the hook-shaped protrusion is screwed to an intermediate portion of the bolt body (Claim 2), and the nut is a tubular member. It can be set as the form (Claim 3) clamped from the both sides of an axial direction by the lock nut of the magnitude | size which covers a protrusion part. In addition, the brace body in the above configuration is a compression brace made only of a circular steel pipe (Claim 4), and a bar steel provided with a plurality of spacer rings at predetermined intervals in the longitudinal direction leaves a gap around the spacer ring. It is also possible to adopt a form of a buckling restrained brace accommodated inside a circular steel pipe (claim 5). Furthermore, as the brace mounting structure according to any one of claims 1 to 5, both ends of the brace are provided on upper and lower gusset plates provided at diagonal positions on a rectangular frame surface of a steel frame having a steel column and a steel beam as a framework. It is good also as a form (Claim 6) by which the expansion-contraction part of a brace is arrange | positioned in the vicinity of a lower gusset plate when pin-joining.

In the brace and its mounting structure according to the present invention, the following effects can be obtained by adopting the above configuration.
(1) In the brace according to the present invention, since the stretchable portion provided between the joining member and the brace body uses a screwed structure of the bolt body and the cylindrical female screw member, the length of the entire brace is adjusted. Can be easily performed in a wide range, and furthermore, pinning is performed on the gusset plate, so that the workability is good.
(2) brace according to the present invention, the rotating operation of the cylindrical member is exposed to the outside in the expansion unit (Tubular), a pair of cylindrical female screw member disposed in a fitting state to the inner side Since it is displaced along the axial direction of the bolt body while sliding with respect to the cylindrical member, even if the brace is attached to the gusset plate, the cylindrical member can be rotated in an appropriate direction. It is possible to reliably introduce tension to the brace body.
(3) When the both ends of the brace are pin-joined to the upper and lower gusset plates on the diagonal position of the rectangular frame surface of the steel frame, the brace's expansion / contraction part is placed near the lower gusset plate If the structure, when used as a brace for receiving a compressive force, bending compressed by the lower end of the brace destruction and local buckling fracture, even when the neck breaking phenomenon or the like is concerned, Oite the stretchable portion, The cylindrical member (circular steel pipe) is fitted to the pair of cylindrical female screw members from the outside at both ends thereof, and the protrusion on the inner peripheral surface is engaged with the flange-shaped protrusion of the bolt body. Thus, it is possible to effectively avoid buckling of the bolt body and to prevent a decrease in yield strength due to bending fracture or buckling at the lower part of the brace.

(A)-(c) is the top view, front view, and partial sectional view which concern on 1st Embodiment of the brace of this invention, respectively. (A)-(c) is the fragmentary sectional view of the expansion-contraction part which is the principal part of this invention, respectively, a front view, and a right view. It is a perspective view of the cylindrical member used with the expansion-contraction part shown in FIG. 2A and 2B are partial cross-sectional views showing the range of expansion / contraction of the expansion / contraction part in FIG. 2, wherein FIG. It is the front view which showed the coupling | bonding method with a gusset plate in construction of the brace which concerns on 1st Embodiment of FIG. It is the front view which showed the method of introduce | transducing tension | tensile_strength in a brace main body as a next process of FIG. It is explanatory drawing which showed the ideal compression bending deformation | transformation state when a compressive force acts on a compression brace or a buckling restraint brace. It is explanatory drawing which showed the behavior when the upper applied point moved below by the compression force acting on the brace. (A)-(c) is the top view, front view, and partial sectional view which concern on 2nd Embodiment of the brace of this invention, respectively. (A) And (b) is the front view and top view which showed the prior art example of the compression brace used for pin joining. It is the front view which showed the prior art example of the compression brace used for fixed joining.

  Embodiments of a brace and its mounting structure according to the present invention will be described below with reference to the drawings. 1A to 1C are a plan view, a front view, and a partial sectional view according to a first embodiment of a brace according to the present invention. The brace 1 shown to Fig.1 (a)-(c) is a compression brace in which the brace main body 2 consists of a circular steel pipe. The joining member 3a coupled to one end of the brace body 2 is obtained by welding a set of two plate members 30 to the opposite end surface of the disc portion 21 welded to the end surface of the circular steel pipe 2. It is. The joining member 3a composed of a set of two plate members 30 is arranged in parallel with a gap between the opposing surfaces so that gusset plates having insertion holes can be inserted, and pin bolt insertion holes 31 are formed on the respective plate members 30 as shafts of each other. It is formed together. In addition, a similar joining member 3b is joined to the other end of the brace body 2 by welding via an expansion / contraction part 4 described later. In addition, the connection means of the expansion-contraction part 4 and the other edge part of the brace main body 2 (circular steel pipe) is also by welding similarly. These joint members 3a and 3b are bifurcated joint hardware generally called a clevis.

2A to 2C are a partial cross-sectional view, a front view, and a side view in which the stretchable portion 4 is enlarged. The expansion / contraction part 4 is comprised with the volt | bolt main body 5, a pair of cylindrical internal thread member 6a, 6b, a pair of lock nut 7a, 7b, and the cylindrical member 8 (circular steel pipe) . The bolt main body 5 has a left screw portion 52a and a left screw portion 52b formed on the left and right sides of the hexagonal hook-shaped protrusion 51 located at the center, respectively, and the right screw portion 52a and the left screw portion 52b. On the other hand, the pair of cylindrical female screw members 6a and 6b and the pair of lock nuts 7a and 7b are screwed together. A pair of cylindrical female screw member 6a, 6b is also referred to as circular nut or high nuts, both internal thread is provided over the entire length, intended to be formed across the cylinder, the cylindrical member 8 made of steel tube On the other hand, it is set to an outer diameter that can be fitted inside . As is clear from FIG. 2 (a) shown in the partial cross section, the hook-shaped protrusion 51 is a hexagon nut screwed into the bolt main body 5, and is smaller than the pair of lock nuts 7a and 7b arranged on both sides thereof. Dimensions are used.

As shown in a single state in FIG. 3, the cylindrical member 8 fitted over the pair of cylindrical female screw members 6a and 6b screwed to both ends of the bolt body 5 is hexagonal at the center of the cylinder. A protrusion 82 having a through-hole 81 having a shape is formed. Such a cylindrical member 8 can be manufactured, for example, by welding a disk-shaped protrusion 82 manufactured as a separate part to a predetermined position inside the circular steel pipe. As shown in FIG. 2A, the hook-like protrusion 51 of the bolt main body 5 is fitted into the through hole 81 of the protrusion 82, and a pair of lock nuts 7 a having a slightly larger dimension than the through hole 81. 7b is sandwiched with respect to the protrusion 82, and the hook-shaped protrusion 51 is sandwiched from both sides to fix the position. With such an internal structure, when the cylindrical member 8 is rotated, the bolt body 5 inside also rotates in the same direction, and a pair of cylindrical female screw members 6a and 6b having different screw portions in the rotational direction are in the rotational direction. Accordingly, it is displaced along the axis of the bolt body 5 while sliding and moving inside the cylindrical member 8 in a direction away from or close to the bolt body 5. FIG. 4 is a partial cross-sectional view showing a minimum length state (a) and a maximum length state (b) in the expansion / contraction range of the expansion / contraction part 4.

  FIG. 5 is a front view showing a bracing method according to the first embodiment of FIG. First, with respect to the upper gusset plate 92 welded to the diagonal position of the rectangular frame surface 9 of the steel frame composed of the steel column 90 and the steel beam 91, it is on one end side of the brace 1 of the first embodiment. The pin bolt 93 is inserted in a state where the insertion hole of the joining member 3a and the insertion hole of the gusset plate 92 are aligned, and the upper portion of the brace 1 is temporarily fixed by screwing the nut from the opposite side. In a state where the brace 1 is suspended by the pin bolt 93, the length of the brace 1 is adjusted by rotating the tubular member 8 (circular steel pipe) of the expansion / contraction part 4. When the pin bolt 93 is inserted at a position where the insertion hole of the joining member 3b on the other end side (lower side) of the brace 1 and the insertion hole 95 of the lower gusset plate 94 coincide with each other, and the nut from the opposite side is tightened The installation of the brace 1 is completed.

  Next, as shown in FIG. 6, when the cylindrical member 8 is rotated in a predetermined direction, the distance between the pair of cylindrical female screw members 6 a and 6 b is narrowed, and a desired tensile axial force is introduced into the brace body 2. Therefore, the bending etc. of the brace main body 2 can be eliminated. In the brace mounting structure of the present invention that is mounted in this manner, the upper and lower gusset plates 92 and 94 and the joining members 3a and 3b of the brace 1 are in a pin joint type, and therefore occur when the brace 1 bears compressive stress. The compression bending deformation can be limited to the deformation in the structural surface surrounded by the column beam, and damage to the outer wall or the like can be prevented. Further, when the tensile force is applied, unlike the fixing type using the high-strength bolt, the pins of the brace body 2 are linear, so that the joining members 3a and 3b are not easily subjected to stress concentration such as bending deformation by the tensile force. .

FIG. 7 is an explanatory view showing an ideal compression bending deformation state when a compression force is applied to the compression brace or the buckling restrained brace. FIG. 8 shows the behavior in which the applied point of the upper part of the brace moves downward when compressive force is applied to the brace in an actual building. In particular, in the lower part of the brace, excessive bending deformation occurs. A vertical compressive force is applied, and bending fracture and local buckling are likely to occur. Therefore, as in the construction example shown in FIGS. 5 and 6, when the stretchable portion 4 of the brace 1 mounted so as to be disposed in the lower gusset plate 94 side, the tubular member 8 (Tubular) whose ends The side portions are fitted to the pair of cylindrical female screw members 6a and 6b from the outside, and the hook-shaped protrusions 51 (hexagons) of the bolt body 5 with respect to the hexagonal through holes 81 provided on the inner peripheral surface. Nut) is in a state of being fitted, and the buckling restraining function of the bolt body 5 by the cylindrical member 8 is sufficiently exerted to prevent a decrease in yield strength due to bending failure or buckling at the lower part of the brace 1. .

  9A to 9C are a plan view, a front view, and a partial cross-sectional view according to a second embodiment of the brace according to the present invention. In addition, the same part as 1st Embodiment is shown with the same code | symbol, and the overlapping description is abbreviate | omitted. In the illustrated brace 1A, the brace body 2A is provided with a plurality of spacer rings 21 at predetermined intervals in the longitudinal direction on a steel bar 20 as a brace core material, and the bar steel 20 is left behind around the steel bar 20 by the spacer ring 21. The structure is housed inside the circular steel pipe 22. This brace 1A is divided into buckling-restrained braces. Male threaded portions 20a and 20b are formed at both ends of the steel bar 20, and are screwed into one of the cylindrical female threaded members 60a and 60b of the telescopic portion 4, respectively. In this case, since the cylindrical female screw members 60a and 60b located on the opposite side to the joining member 3 at the end part are screwed with both the male screw part of the bolt body 5 and the male screw parts 20a and 20b of the steel bar 20, It is formed longer than that of one embodiment. In this embodiment, since the elastic parts 4 are provided on both sides of the brace body 2A, the adjustment range of the overall length of the brace can be further expanded.

  As mentioned above, although the structure of this invention and its effect were demonstrated based on embodiment, this invention is not limited to the said embodiment. For example, it is possible to use a member other than clevis as the joining member, and one end of the brace is not an intersection of the steel column and the steel beam, but straddles the steel plate and the base plate joined to the lower end thereof. Of course, various modifications can be made within the technical idea of the present invention, such as joining to the provided gusset plate. In each of the above-described embodiments, the description has been made mainly for the compression brace and the buckling restrained brace that bear the compressive force, but it can be used as a tension brace.

  The brace and its mounting structure of the present invention can adjust the length of the brace and introduce tension by rotating the tubular member of the stretchable part provided between the joining member and the brace body. Further development of use as a brace for reinforcement is expected.

  DESCRIPTION OF SYMBOLS 1,1A: Brace, 2, 2A, 10: Brace main body, 3, 3a, 3b, 11, 15: Joining member, 4: Expansion part, 5: Bolt main body, 6a, 6b, 60a, 60b: Cylindrical female screw member 7a, 7b: lock nut, 8: cylindrical member, 9: rectangular frame surface, 11a, 15a, 31, 95: insertion hole, 12, 16, 92, 94: gusset plate, 20: brace core material, 21 : Spacer, 22: Circular steel pipe (buckling restraint pipe), 51: Hook-like projection, 81: Through hole, 82: Projection, 90: Column, 91: Beam, 93: Pin bolt

Claims (6)

A brace provided with an expansion / contraction part between a joining member at an end joined to a gusset plate attached to a rectangular frame surface of a steel frame having a steel column and a steel beam as a framework, and the brace body, the expansion / contraction part Is a bolt body in which both sides of the hook-shaped protrusion are formed as a right screw and a left screw, and screwed at one end to the left and right male thread portions of the bolt body, and the other end is joined to the brace body. A pair of cylindrical female screw members coupled to the member, and the pair of cylindrical female screw members screwed to both ends of the bolt main body in a state in which the protrusions on the inner peripheral surface are engaged with the flange-shaped protrusions of the bolt main body And a cylindrical member made of a circular steel pipe that is externally fitted across the tube, and by rotating the cylindrical member, the internal bolt body is rotated to slide the pair of cylindrical female screw members inside the cylindrical member. moved toward or away from while Brace which is a formed.
  The brace according to claim 1, wherein the hook-like protrusion of the expansion / contraction part is a nut screwed to an intermediate part of the bolt body.   The brace according to claim 2, wherein the nut of the expansion / contraction part is clamped from both sides in the axial direction by a lock nut having a size covering the protrusion of the cylindrical member.   The brace according to any one of claims 1 to 3, wherein the brace body is made of a circular steel pipe.   The brace body is composed of a steel bar in which a plurality of spacer rings are provided at predetermined intervals in the longitudinal direction, and a round steel pipe that accommodates the steel bar inside the spacer ring leaving a gap around the periphery. The brace according to any one of 1 to 3.   A brace mounting structure in which both ends of a brace according to claim 1 are pin-bonded to upper and lower gusset plates provided at diagonal positions on a rectangular frame surface of a steel frame having a steel column and a steel beam as a framework. The brace mounting structure is characterized in that the elastic part of the brace is disposed in the vicinity of the lower gusset plate.

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