The present invention relates to a junction structure between structures and a beam junction method, and in particular, to a junction structure between structures and a beam junction method by bolt junction, which have a high strength, use less welding, and can improve workability at a high altitude.
Conventionally, beams have been joined together with a bolt via a plate (Refer to, for example, Patent document 1).
The H-steel beams can be joined together with the bolt via the plate. However, the H-steel beams have a larger height than rectangular beams having a rectangular cross section, resulting in weaker bending strength.
However, for the rectangular beams having a rectangular cross section, friction joining using the bolt is difficult, therefore, welding was required. However, welding takes time and effort and further, accompanies work at a high altitude, which is dangerous.
In consideration of the above-mentioned problems, the present invention provides a junction structure between structures and a beam junction method, having a high strength, enabling friction joining using a bolt, using less welding, and improving workability at a high altitude.
In a junction structure between structures according to the present invention, by providing an inclined portion of a first beam inclined at A degrees (A<90), an inclined portion of a second beam inclined at B degrees (180 degrees−A degrees), an inclined portion of the first′ beam inclined at A degrees (A<90), and an inclined portion of the second beam inclined at B degrees (180 degrees−A degrees), three surfaces other than an upper surface of the first beam can be joined to respective three surfaces other than an upper surface of the second beam by being sandwiched between plates from inner and outer sides and joined together with bolts and nuts in this state, and the upper surfaces can be joined to each other by welding. As a result, the junction structure that has a high strength, uses less welding as compared to the junction structure between structures having four welded surfaces, and improves workability at a high altitude, can be realized.
In the junction structure between structures according to the present invention, by providing the inclined portion of the first beam inclined at A degrees (A<90) and the inclined portion of the second beam inclined at B degrees (180 degrees−A degrees), three surfaces other than an upper surface of the first beam can be joined to respective three surfaces other than an upper surface of the second beam by being sandwiched between plates from inner and outer sides and joined together with bolts and nuts, and the upper surfaces can be joined by welding. Thus, the junction structure between structures that has a high strength, uses less welding as compared to the junction structure between structures having four welded surfaces, and improves workability at a high altitude can be realized.
According to a beam junction method of the present invention, by providing the inclined portion of the first beam inclined at A degrees (A<90) and the inclined portion of the second beam inclined at B degrees (180 degrees−A degrees), three surfaces other than an upper surface of the first beam can be joined to respective three surfaces other than an upper surface of the second beam by being sandwiched by a first inner front plate, a first outer front plate, a first inner back plate, a first outer back plate, a first inner bottom plate, and a first outer bottom plate from inner and outer sides and joined together with bolts and nuts, and the upper surfaces can be joined by welding. Thus, the junction structure between structures that has a high strength, uses less welding as compared to the junction structure between structures having four welded surfaces, and improves workability at a high altitude can be realized.
A junction structure between structures and a beam junction method in accordance with an embodiment of the present invention will be described with reference to
A junction structure C between structures shown in
The beam 3 has a first beam 31, a second beam 32, and a first′ beam 33 from the first column 1 toward the first′ column 2.
The first column 1 and the first beam 31, and the first′ column 2 and the first′ beam 33 are previously connected to each other by welding or the like, on the ground, not at a high altitude.
As shown in
That is, as shown in
The above-mentioned angle A is smaller than 90 degrees, and practically, in the range of about 30 degrees to about 60 degrees, more desirably, 45 degrees.
As shown in
That is, the second beam 32 has a second front portion 32A, a second upper portion 32B, a second back portion 32C, and a second bottom portion 32D when viewed from the front. On an end surface of the second beam 32 toward the first column when viewed from the above, the upper portion 32B of the second beam 32 protrudes from the bottom portion 32D of the second beam 32 toward the first column 1. The front portion 32A of the second beam 32 and the back portion 32C of the second beam 32 on the side of the first column 1 forms a second inclined surface Y inclined at the same angle B (180 degrees−A degrees) so as to incline toward the first column 1 in the horizontal direction. On an end surface of the second beam 32 toward the first′ column 2, when viewed from the above, the upper portion 32B of the second beam 32 protrudes from the bottom portion 32D of the second beam 32 toward the first′ column 2, and the front portion 32A of the second beam 32 and the back portion 32C of the second beam 32 on the side of the first′ column 2 form a second′ inclined surface Y′ inclined at the same angle B so as to incline toward the first′ column 2 in the horizontal direction.
The first′ beam 33 has a substantially trapezoidal shape having its lower base that is longer than its upper base when viewed from the front. An angle that an inclined portion of the first′ beam 33 on the side of the first′ column 2 forms the lower base is 90 degrees, and an angle that an inclined portion X′ of the first′ beam 33 on the side of the first column 1 forms with the lower base is A degrees.
That is, the first′ beam 33 has a front portion 33A of the first′ beam 33, an upper portion 33B of the first′ beam 33, a back portion 33C of the first′ beam 33, and a bottom portion 33D of the first′ beam 33 when viewed from the front. On an end surface of the first′ beam 33 on the opposite side of the first′ column 2, when viewed from the above, the bottom portion 33D of the first′ beam 33 protrudes from the upper portion 33B of the first′ beam 33 toward the first column 1. The front portion 33A of the first′ beam 33 and the back portion 33C of the first′ beam 33 form a first′ inclined surface X′ inclined at the same angle A so as to decline toward the first column 1 in the horizontal direction.
As shown in
As shown in
Three surfaces other than an upper surface of the first beam 31 are joined to respective three surfaces other than an upper surface of the second beam 32 by being sandwiched between plates (P1 to P6) from inner and outer side and joined together with bolts (B1 to B8) and nuts (N1 to N8), which will be described later in detail and the upper surfaces are joined to each other by welding contact portions of the upper portion 31B of the first beam 31 and the upper portion 32B of the second beam 32 together. Three surfaces other than an upper surface of the first′ beam 33 are joined to respective three surfaces other than an upper surface of the second beam 32 by being sandwiched between plates (P1′ to P6′) from inner and outer side and joined together with nuts (N1′ to N8′), which will be described later in detail, and the upper surfaces are joined to each other by welding contact portions of the upper portion 33B of the first′ beam 33 and the upper portion 32B of the second beam 32.
That is, the front portion 31A of the first beam 31 and the front portion 32A of the second beam 32 are joined to each other by being sandwiched between a first inner front plate P1 that is located on the inner side of the beam 3 (31, 32) and extends over the front portion 31A of the first beam 31 and the front portion 32A of the second beam 32 and a first outer front plate P2 that is located on the outer side of the beam 3 (31, 32) and extends over the front portion 31A of the first beam 31 and the front portion 32A of the second beam 32, and joined with the bolts (B1 to B2) and the nuts (N1 to N2).
The back portion 31C of the first beam 31 and the back portion 32C of the second beam 32 are joined to each other by being sandwiched between a first inner back plate P3 that is located on the inner side of the beam 3 (31, 32) and extends over the back portion 31C of the first beam 31 and the back portion 32C of the second beam 32 and a first outer back plate P4 that is located on the outer side of the beam 3 (31, 32) and extends over the back portion 31C of the first beam 31 and the back portion 32C of the second beam 32, and joined with the bolts (B3 to B4) and the nuts (N3 to N4).
The bottom portion 31D of the first beam 31 and the bottom portion 32D of the second beam 32 are joined to each other by being sandwiched between a first inner bottom plate P5 that is located on the inner side of the beam 3 (31, 32) and extends over the bottom portion 31D of the first beam 31 and the bottom portion 32D of the second beam 32 and a first outer bottom plate P6 that is located on the outer side of the beam 3 (31, 32) and extends over the bottom portion 31D of the first beam 31 and the bottom portion 32D of the second beam 32, and joined with the bolts (B5 to B8) and the nuts (N5 to N8).
Contact portions (X2, Y2) of the first upper portion 31B and the second upper portion 32B are joined to each other by welding. P is a plate provided on the inner side so as to extend over joined portions of the first upper portion 31B and the second upper portion 32B (
The front portion 33A of the first′ beam 33 and the front portion 32A of the second beam 32 are joined to each other by being sandwiched between a first′ inner front plate P1′ that is located on the inner side of the beam 3 (32, 33) and extends over the front portion 33A of the first′ beam 33 and the front portion 32A of the second beam 32 and a first′ outer front plate P2′ that is located on the outer side of the beam 3 (32, 33) and extends over the front portion 33A of the first′ beam 33 and the front portion 32A of the second beam 32, and joined with the bolts (B1′ to B2′) and the nuts (N1′ to N2′).
The back portion 33C of the first′ beam 33 and the back portion 32C of the second beam 32 are joined to each other by being sandwiched between a first′ inner back plate P3′ that is located on the inner side of the beam 3 (32, 33) and extends over the back portion 33C of the first′ beam 33 and the back portion 32C of the second beam 32 and a first′ outer back plate P4′ that is located on the outer side of the beam 3 (32, 33) and extends over the back portion 33C of the first′ beam 33 and the back portion 32C of the second beam 32, and joined with the bolts (B3′ to B4′) and the nuts (N3′ to N4′).
The bottom portion 33D of the first′ beam 33 and the bottom portion 32D of the second beam 32 are joined to each other by being sandwiched between a first′ inner bottom plate P5′ that is located on the inner side of the beam 3 (32, 33) and extends over the bottom portion 33D of the first′ beam 33 and the bottom portion 32D of the second beam 32 and a first′ outer bottom plate P6′ that is located on the outer side of the beam 3 (32, 33) and extends over the bottom portion 33D of the first′ beam 33 and the bottom portion 32D of the second beam 32, and joined with the bolts (B5′ to B8′) and the nuts (N5′ to N8′).
Accordingly, in the above-mentioned junction structure C between structures, by providing the inclined portion X of the first beam 31 inclined at A degrees (A<90), the inclined portion Y of the second beam 32 inclined at B degrees (180 degrees−A degrees), the inclined portion X′ of the first′ beam 33 inclined at A degrees (A<90), and the inclined portion Y′ of the second beam 32 inclined at B degrees (180 degrees−A degrees). The three surfaces other than the upper surface of the first beam 31 and the three surfaces other than the upper surface of the second beam 32 are sandwiched between the plates (P1 to P6) from the inner and outer sides, and joined together with the bolts (B1 to B8) and the nuts (N1 to N8) in this state, respectively, and the upper surfaces can be joined to each other by welding. Thus, the junction structure between structures that has a high strength, uses less welding as compared to the junction structure between structures having four welded surfaces, and improves workability at a high altitude can be realized.
Next, a junction method of the beam 3 formed by connecting the rectangular first beam 31 having a rectangular cross section to the rectangular second beam 32 having a rectangular cross section will be described below with reference to
When viewed from the front, a portion of the first beam 31 to be connected to the second beam 32 is the first inclined surface X formed from the bottom portion 31D of the first beam 31 toward the upper portion 31B at A degrees (A<90), and a portion of the second beam 32 to be connected to the first beam 31 is the second inclined surface Y formed from the bottom portion 32D of the second beam 32 toward the upper portion 32B at B degrees (180 degrees−A degrees).
The connection portions of the front portion 31A of the first beam 31 and the front portion 32A of the second beam 32 are sandwiched between the first inner front plate P1 on the inner side and the first outer front plate P2 on the outer side. The connection portions of the back portion 31C of the first beam 31 and the back portion 32C of the second beam 32 are sandwiched between the first inner back plate P3 on the inner side and the first outer back plate P4 on the outer side. The connection portions of the bottom portion 31D of the first beam 31 and the bottom portion 32D of the second beam 32 are sandwiched between the first inner bottom plate P5 on the inner side and the first outer bottom plate P6 on the outer side.
As shown in
The front portion 31A of the first beam 31 has a temporary tightening front hole o corresponding to the first outer temporary tightening front hole a and the first inner temporary tightening front hole c, and the front portion 32A of the second beam 32 has a first front hole e corresponding to the first inner front threaded hole d and the first outer front hole b.
Accordingly, to couple the front portion 31A of the first beam 31 to the front portion 32A of the second beam 32, the first inner front plate P1 and the first outer front plate P2 are temporarily tightened to the inner side and the outer side of the front portion 31A of the first beam 31, respectively, through the first outer temporary tightening front hole a, the temporary tightening front hole o, and the first inner temporary tightening front hole c with the bolt B (first bolt B1) and the nut N (first nut N1) (Refer to
As shown in
The back portion 32C of the second beam 32 has a first back hole j corresponding to the first outer back hole g and the first inner back threaded hole i.
Accordingly, to couple the back portion 31C of the first beam 31 to the back portion 32C of the second beam 32, the first inner back plate P3 and the first outer back plate P4 are temporarily tightened to the inner and outer sides of the back portion 31C of the first beam 31 through the first outer temporary tightening back hole f, the temporary tightening back hole z, and the first inner temporary tightening back hole h with the bolt B (third bolt B3) and the nut N (third nut N3), the bolt B (fourth bolt B4) is screwed into the first inner back threaded hole i, vertically arranged and temporarily tightened such that an end opposite to its head is externally located [This state is referred to as “first back state” (Refer to
As shown in
The first inner bottom plate P5 sequentially has a first inner temporary tightening bottom hole s, a first inner bottom threaded hole t in which is female screw is cut, and a second inner bottom threaded hole u in which is female screw is cut toward the outer side, the first inner bottom threaded hole t corresponds to the second outer bottom hole r, and the second inner bottom threaded hole u corresponds to the first outer bottom hole n.
The bottom portion 31D of the first beam 31 sequentially has a first beam inner bottom hole v and a first beam outer bottom hole w toward the outer side, the first beam inner bottom hole v corresponds to the first outer temporary tightening bottom hole m, and the first beam outer bottom hole w corresponds to the first outer bottom hole n and the second inner bottom threaded hole u.
The bottom portion 32D of the second beam 32 sequentially has a second beam inner bottom hole x and a second beam outer bottom hole y toward the outer side, the second beam inner bottom hole x corresponds to the first inner temporary tightening bottom hole s, and the second beam outer bottom hole y corresponds to the first inner bottom threaded hole t and the second outer bottom hole r.
Accordingly, to couple the bottom portion 31D of the first beam 31 to the bottom portion 32D of the second beam 32, the first outer bottom plate P6 is temporarily tightened to the outer side of the bottom portion 31D of the first beam 31 through the first beam inner bottom hole v, and the first outer temporary tightening bottom hole m with the bolt B (eighth bolt B8) and the nut N (eighth nut N8) [This state is referred to as “first bottom state” (Refer to
The first inner bottom plate P5 is temporarily tightened to the inner side of the bottom portion 32D of the second beam 32 through the first inner temporary tightening bottom hole s and the second beam inner bottom hole x with the bolt B (fifth bolt B5) and the nut N (fifth nut N5), the bolts B (sixth bolt B6, seventh bolt B7) are screwed into the first inner bottom threaded hole t and the second inner bottom threaded hole u, respectively, vertically arranged and temporarily tightened such that end opposite to their heads are externally located [This state is referred to as “second bottom state” (Refer to
After tightening (final tightening) of the bolts B (first bolt B1 to eighth bolt B8) with the nuts N (first nut N1 to eighth nut N8), by joining contact portions of the upper portion 31B of the first beam 31 and the upper portion 32B of the second beam 32 to each other by welding, the first beam 31 can be joined to the second beam 32.
Accordingly, according to the above-mentioned beam junction method, the inclined portion X of the first beam 31 inclined at A degrees (A<90) and the inclined portion Y of the second beam 32 inclined at B degrees (180 degrees−A degrees) are provided, and the inclined portion X of the first beam 31 inclined at A degrees (A<90) contacts with the inclined portion Y of the second beam 32 inclined at B degrees (180 degrees−A degrees). Three surfaces other than an upper surface are sandwiched by the first inner front plate P1, the first outer front plate P2, the first inner back plate P3, the first outer back plate P4, the first inner bottom plate P5, and the first outer bottom plate P6 from the inner and outer sides with the first bolt B1 to eighth bolt B8 and the first nut N1 to eighth nut N8, and the upper surfaces are joined to each other by welding. Thus, the junction structure between structures that has a high strength, uses less welding as compared to the junction structure between structures having four welded surfaces, and improves workability at a high altitude can be realized.
Next, a junction method of the beam 3 formed by connecting the rectangular second beam 32 having a rectangular cross section to the rectangular third beam 33 having a rectangular cross section will be described below with reference to
When viewed from the front, a portion of the second beam 32 to be connected to the third beam 33 is the second inclined surface Y′ formed from the bottom portion 32D of the second beam 32 toward the upper portion 32B at B degrees (180 degrees−A degrees). When viewed from the front, a portion of the third beam 33 connecting to the second beam 32 is the first inclined surface X′ formed from the bottom portion 33D of the third beam 33 toward the upper portion 33B at A degrees (A<90).
The connection portions of the front portion 32A of the second beam 32 and the front portion 33A of the third beam 33 are sandwiched between the first′ inner front plate P1′ on the inner side and the first′ outer front plate P2′ on the outer side. The connection portions of the back portion 32C of the second beam 32 and the back portion 33C of the third beam 33 are sandwiched between the first′ inner back plate P3′ on the inner side and the first′ outer back plate P4′ on the outer side. The connection portions of the bottom portion 32D of the second beam 32 and the bottom portion 33D of the third beam 33 are sandwiched between the first′ inner bottom plate P5′ on the inner side and the first′ outer bottom plate P6′ on the outer side.
As shown in
The front portion 32A of the second beam 32 has a first′ front hole e′ corresponding to the first′ outer front hole b′ and the first′ inner front threaded hole d′. The front portion 33A of the third beam 33 has a temporary tightening front hole o′, and the temporary tightening front hole o′ corresponds to the first′ inner temporary tightening front hole c′ and the first′ outer temporary tightening front hole a′.
Accordingly, to couple the front portion 32A of the second beam 32 to the front portion 33A of the third beam 33, the first′ inner front plate P1′ and the first′ outer front plate P2′ are temporarily tightened to the inner and outer sides of the front portion 33A of the third beam 33 through the first′ outer temporary tightening front hole a′, the temporary tightening front hole o′, and the first′ inner temporary tightening front hole c′ with the bolt B (first′ bolt B1′) and the nut N (first′ nut N1′). The bolt B (second′ bolt B2′) is screwed into the first′ inner front threaded hole d′, vertically arranged and temporarily tightened such that an end opposite to its head is externally located [This state is referred to as “first′ front state” (Refer to
As shown in
The back portion 33C of the third beam 33 has a temporary tightening back hole z′, and the temporary tightening back hole z′ corresponds to the first′ outer temporary tightening back hole f′ and the first′ inner temporary tightening back hole h′.
The back portion 32C of the second beam 32 has a first′ back hole j′, and the first′ back hole j′ corresponds to the first′ inner back threaded hole i′ and the first′ outer back hole g′.
Accordingly, to couple the back portion 32C of the second beam 32 to the back portion 33C of the third beam 33, the first′ inner back plate P3′ and the first′ outer back plate P4′ are temporarily tightened to the inner and outer sides of the back portion 33C of the third beam 33 through the first′ outer temporary tightening back hole f′, the temporary tightening back hole z′, and the first′ inner temporary tightening back hole h′ with the bolt B (third′ bolt B3′) and the nut N (third′ nut N3′). The bolt B (fourth′ bolt B4′) is screwed into the first′ inner back threaded hole i′, vertically arranged and temporarily tightened such that an end opposite to its head is externally located [This state is referred to as “first′ back state” (Refer to
As shown in
The first′ inner bottom plate P5′ sequentially has a first′ inner temporary tightening bottom hole s′, a first′ inner bottom threaded hole t′ in which is female screw is cut. A second′ inner bottom threaded hole u′ in which is female screw is cut toward the outer side, the first′ inner bottom threaded hole t′ corresponds to the second outer bottom hole r′, and the second′ inner bottom threaded hole u′ corresponds to the first outer bottom hole n′.
The bottom portion 33D of the third beam 33 sequentially has a first′ beam inner bottom hole v′ and a first′ beam outer bottom hole w′ toward the outer side, the first′ beam inner bottom hole v′ corresponds to the first′ outer temporary tightening bottom hole m′, and the first′ beam outer bottom hole w′ corresponds to the first outer bottom hole n′.
The bottom portion 32D of the second beam 32 sequentially has a second′ beam inner bottom hole x′ and a second′ beam outer bottom hole y′ toward the outer side, the second′ beam inner bottom hole x′ corresponds to the first inner temporary tightening bottom hole s′, and the second′ beam outer bottom hole y′ corresponds to the first′ inner bottom threaded hole t′.
Accordingly, to couple the bottom portion 32D of the second beam 32 to the bottom portion 33D of the third beam 33, the first′ outer bottom plate P6′ is temporarily tightened to the outer side of the bottom portion 33D of the first′ beam 33 through the first′ beam inner bottom hole v′ and the first′ outer temporary tightening bottom hole m′ with the bolt B (eighth′ bolt B8′) and the nut N (eighth′ nut N8′) [This state is referred to as “first′ bottom state” (Refer to
The first′ inner bottom plate P5′ is temporarily tightened to the inner side of the bottom portion 32D of the second beam 32 through the first′ inner temporary tightening bottom hole s′ and the second′ beam inner bottom hole x′ with the bolt B (fifth′ bolt B5′) and the nut N (fifth′ nut N5′). The bolts B (sixth′ bolt B6′, seventh′ bolt B7′) are screwed into the first′ inner bottom threaded hole t′ and the second′ inner bottom threaded hole u′, respectively, vertically arranged and temporarily tightened such that ends opposite to their heads are externally located [This state is referred to as “second′ bottom state” (Refer to
After tightening (final tightening) of the above-mentioned bolts B (first′ bolt B1′ to eighth′ bolt B8′) with the nut N [first′ nut N1′ to eighth′ nut N8′), the contact portions of the upper portion 32B of the second beam 32 and the upper portion 33B of the third beam 33 are joined together by welding, thereby joining the second beam 32 to the third beam 33. P′ is a plate provided on the inner side so as to extend over the upper portion 32B of the second beam 32 and the upper portion 33B of the third beam 33 (
In the above-mentioned embodiment, the first inner front plate P1 and the first outer front plate P2 are attached to the front portion 31A of the first beam 31, and the first inner back plate P3 and the first outer back plate P4 are attached to the back portion 31C of the first beam 31 to couple the first beam 31 to the second beam 32. However, the present invention is not limited to this, and the first inner front plate P1 and the first outer front plate P2 may be attached to the front portion 32A of the second beam 32, and the first inner back plate P3 and the first outer back plate P4 may be attached to the back portion 32C of the second beam 32 (Refer to
Since the first inner front plate P1 and the first outer front plate P2 are attached to the second beam 32, not to the first beam 31, the first front hole e provided in the front portion 32A of the second beam 32 is replaced with the temporary tightening front hole in this embodiment, and the temporary tightening front hole o provided in the front portion 31A of the first beam 31 is replaced with the first front hole e in this embodiment.
Since the first inner back plate P3 and the first outer back plate P3 are attached to the second beam 32, not to the first beam 31, the first back hole j provided in the back portion 32C of the second beam 32 is replaced with the temporary tightening back hole z in this embodiment, and the temporary tightening back hole z provided in the back portion 31C of the first beam 31 is replaced with the first back hole j in this embodiment.
That is, as shown in
As shown in
As shown in
To couple the back portion 31C of the first beam 31 to the back portion 32C of the second beam 32, the first inner back plate P3 and the first outer back plate P4 are temporarily tightened to the inner and outer sides of the back portion 32C of the second beam 32 through the first inner back threaded hole i, the first outer temporary tightening back hole f, the temporary tightening back hole z, and the first inner temporary tightening back hole h with the bolt B (third bolt B3) and the nut N (third nut N3). The bolt B (fourth bolt B4) is screwed into the first inner front threaded hole d, vertically arranged and temporarily tightened such that an end opposite to its head is externally located [This state is referred to as “first′ back state” (Refer to
Since coupling of the bottom portion 31D of the first beam 31 to the bottom portion 32D of the second beam 32 in this embodiment (
In the above-mentioned embodiment, the first′ inner front plate P1′ and the first′ outer front plate P2′ are attached to the front portion 33A of the first′ beam 33, and the first′ inner back plate P3′ and the first′ outer back plate P4′ are attached to the back portion 33C of the first′ beam 33, thereby joining the first′ beam 33 to the second beam 32. However, the present invention is not limited to this, and the first′ inner front plate P1′ and the first′ outer front plate P2′ may be attached to the front portion 32A of the second beam 32, and the first′ inner back plate P3′ and the first′ outer back plate P4′ may be attached to the back portion 32C of the second beam 32 (Refer to
Since the first′ inner front plate P1′ and the first′ outer front plate P2′ are attached to the second beam 32, not to the first′ beam 33, the first′ front hole e′ provided in the front portion 32A of the second beam 32 is replaced with the temporary tightening front hole o′ in this embodiment, and the temporary tightening front hole o′ provided in the front portion 33A of the first′ beam 33 is replaced with the first′ front hole e′ in this embodiment.
Since the first′ inner back plate P3′ and the first′ outer back plate P4′ are attached to the second beam 32, not to the first′ beam 33, the first′ back hole j′ provided in the back portion 32C of the second beam 32 is replaced with the temporary tightening back hole z′ in this embodiment, and the temporary tightening back hole z′ provided in the back portion 33C of the first′ beam 33 is replaced with the first′ back hole j′ in this embodiment.
That is, as shown in
As shown in
As shown in
To couple the back portion 33C of the first′ beam 33 to the back portion 32C of the second beam 32, the first′ inner back plate P3′ and first′ outer back plate P4′ are temporarily tightened to the inner and outer sides of the back portion 32C of the second beam 32 through the first′ outer temporary tightening back hole f′, the temporary tightening back hole z′, the first′ inner temporary tightening back hole h′ and the first′ inner back threaded hole i′ with the bolt B (third bolt B3′) and the nut N (third nut N3′). The bolt B (fourth bolt B4′) is screwed into the first inner front threaded hole d, vertically arranged and temporarily tightened such that an end opposite to its head is externally located [This state is referred to as “first′ back state” (Refer to
Since coupling of the bottom portion 33D of the first′ beam 33 to the bottom portion 32D of the second beam 32 in this embodiment (