Method for manufacturing column-beam joint structure and the column-beam joint structure

Abstract

Provided is a column-beam joint structure 1, wherein a plurality of thick-walled portions 3, notches 7, and narrow-width portions 9a on a central side of a flange plate 5 are formed integrally, cutting (dividing) is effected at a cut line 8, and the thick-walled portion 3 is welded and joined to a column 2a.

Claims

1. A method for manufacturing a flange plate for a column-beam joint structure comprising: providing a steel plate for a beam, the steel plate having a longitudinal axis, the steel plate having a length measured in a length direction along the longitudinal axis, a thickness measured in a thickness direction transverse to the length direction, and a width measured in a width direction that is transverse to the thickness direction and the length direction; forming in the steel plate a first wall portion that has a first thickness measured in the thickness direction and a pair of second wall portions, each spaced along the length direction relative to the first wall portion, each said second wall portion having a second thickness, the first thickness being relatively greater than each said second thickness, each second wall portion being formed to have the relatively smaller second thickness by rolling the steel plate in the length direction using one or more rollers that rotate about a horizontal roller axis, but excluding rolling of the first wall portion, the first wall portion being centrally located along the steel plate between the pair of second wall portions; forming a pair of notches in said relatively smaller second thickness of each of said pair of second wall portions apart from the relatively thicker first wall portion by rolling using one or more rollers that rotate about a vertical roller axis; and forming each said second wall portion to have a portion extending adjacent to each said pair of notches towards a free end of each of said second wall portions, each free end of said second wall portions having a second width in the width direction that is less than a first width in the width direction of the first wall portion, by rolling using the one or more rollers that rotate about the vertical roller axis.

2. The method for manufacturing a flange plate according to claim 1, wherein each said rolling is performed repeatedly to sequentially form the first wall portion with the relatively greater first thickness, each said pair of notches, and each said second wall portion with the relatively smaller second width.

3. The method for manufacturing a flange plate according to claim 1, wherein the pair of notches in each pair of second wall portions comprises two notches formed in the relatively smaller second width of a respective one of said pair of second wall portions apart from the relatively greater first thickness of the first wall portion by cutting, and, the relatively smaller second width of each said second wall portion is formed by cutting.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an explanatory plan view of a preferred embodiment of a flange plate for a beam in a column-beam joint structure of the invention (First Embodiment);

(2) FIG. 2 is a partial explanatory view of FIG. 1 (First Embodiment);

(3) FIG. 3 is an explanatory view illustrating an embodiment of upper and lower flange plates in the invention (First Embodiment);

(4) FIG. 4 is an explanatory view of a beam illustrating an embodiment of the column-beam joint structure of the invention (First Embodiment);

(5) FIG. 5 is an explanatory plan view of the beam illustrating an embodiment of the column-beam joint structure of the invention (First Embodiment);

(6) FIG. 6 is a vertical cross-sectional view of the beam illustrating another embodiment of the column-beam joint structure of the invention (First Embodiment);

(7) FIG. 7 is an explanatory view illustrating an initial shape in a first step in the process of manufacturing the flange plate for a beam in accordance with the invention (First Embodiment);

(8) FIG. 8 is an explanatory view illustrating a thick-walled portion and thin-walled portions in a second step in the process of manufacturing the flange plate in accordance with the invention (First Embodiment);

(9) FIG. 9 is an explanatory view illustrating a state in which notches have been formed in a third step in the process of manufacturing the flange plate in accordance with the invention (First Embodiment);

(10) FIG. 10 is a view illustrating a rolling machine for rolling the flange plate in accordance with the invention (First Embodiment);

(11) FIG. 11 is a view illustrating a rolling machine for rolling an H-shaped steel for a beam in accordance with the invention (Second Embodiment);

(12) FIG. 12 is an explanatory view illustrating an initial shape in a first step in the process of manufacturing an H-shaped steel in accordance with the invention (Second Embodiment);

(13) FIG. 13 is an explanatory view illustrating thick-walled portions and thin-walled portions in a second step in the process of manufacturing an H-shaped steel beam structure in accordance with the invention (Second Embodiment);

(14) FIG. 14 is an explanatory view illustrating a state in which notches have been formed in a third step in the process of manufacturing an H-shaped steel beam structure in accordance with the invention (Second Embodiment); and

(15) FIG. 15 is an explanatory cross-sectional plan view of an example of a conventional column-beam joint structure.

MODE FOR CARRYING OUT THE INVENTION

(16) Next, a more detailed description will be given of the mode for carrying out the invention on the basis of preferred embodiments illustrated in the drawings. It should be noted that the present invention is not limited to these embodiments.

First Embodiment

(17) In FIGS. 1 to 6, a column-beam joint structure 1 includes a column 2a and a beam 2 joined to the column 2a. One end 51 of a flange plate 5 has a substantially horizontal surface and is joined to a column surface of the column 2a by welding at a column-beam joint part 2b. A thick-walled portion (bulged portion) 3 is present at this welded portion. A web plate 4 of the beam 2 is joined to the column 2a by welding. The beam 2 is a built-up H-shaped beam assembled by welding. The other end 52 of the flange plate 5 is butt-welded to a flange plate 5a at a central portion in a material axial direction A (longitudinal direction of the beam 2) of the beam 2 by a weld zone 6. The flange plate 5 and the flange plate 5a at the central portion are joined to the web plate 4 by welding 6a to form the built-up H-shaped beam. Preferably, the flange plate 5, the flange plate 5a at the central portion, and the web plate 4 are joined in the form of the beam 2 by welding at a factory and is joined to the column 2a at the time of steel frame erection.

(18) In the column-beam joint structure 1, although the web plate 4 of the beam 2 is welded and joined to the column 2a, the web plate 4 of the beam 2 may alternatively be joined to the column 2a through a gusset plate and bolts (not shown).

(19) When an external force generated in the beam 2 is applied to the column-beam joint structure 1 at the time of an earthquake, bending stress occurring in the beam 2 is large at the column-beam joint part 2b and becomes gradually smaller with an increasing distance from the column-beam joint part 2b. Larger bending stress is applied to the column-beam joint part 2b than at a position distant from the column-beam joint part 2b. However, with the column-beam joint structure 1, since the one end 51 of the flange plate 5 is reinforced at the column-beam joint part 2b by the thick-walled portion (bulged portion) 3 which is formed to be wider than the width of the other end 52 of the flange plate 5 in a widthwise direction of the beam 2 and to be thicker than the thickness of the other end 52 of the flange plate 5 in a vertical direction V, and a notch 7 is formed in the flange plate 5 at a position apart from the column 2a, even if a large external force which is of such a measure that a ductile fracture or a brittle failure can occur is applied to the column-beam joint part 2b, plastic deformation is made to occur at the notch 7 so as to form a yield hinge before a ductile fracture or a brittle failure occurs at the column-beam joint part 2b.

(20) Since the flange plate 5 is formed from a steel plate by roll forming in a state in which the notches 7 are provided thereon, it is unnecessary to provide reinforcing plates or the like on the flange plate 5 by welding or the like. In addition, reduction of the amount of steel can be achieved by using a steel plate of a high strength material as the flange plate 5 corresponding to the beam end portion where the stress is large and by using a steel plate of an ordinary material as the flange plate 5a corresponding to the central portion of the beam 2a where the stress is small. Furthermore, the degree of freedom in design is enlarged since it is possible to freely change the amount of notch on the flange plate 5 constituting the notch 7, the enlarged width of the flange plate 5 at the column-beam joint part 2b, and the thickness of the flange plate 5.

(21) The followings are formed in a steel plate 10 for the column-beam joint structure: the thick-walled portion (bulged portion) 3 provided in the central portion in the material axis direction A; a pair of thin-walled portions 9 respectively provided on both sides in the material axis direction A of the thick-walled portion 3; the two pairs of notches 7 each pair of which are provided on the respective thin-walled portion 9; and a narrow-width portion 9a provided on each thin-walled portion 9 and formed to be narrow in a widthwise direction B of the beam 2, and the pair of flange plates 5 and 5a are formed integrally. A plurality of pairs of flange plates 5 and 5a are formed integrally and are cut off at a cut line 8, to thereby form the flange plate 5 shown in FIG. 2. FIG. 3 is an explanatory view of a pair of flange plates 5. The flange plate 5 is formed such that the outer cross-sectional size of the H-shaped steel becomes identical, and the thick-walled portion (bulged portion) 3 is formed in such a manner as to project from one surface of the flange plate 5 so as to jut out (bulge) toward the web plate 4 side.

(22) As shown in FIGS. 7 to 10, the steel plate 10 (elongated body) is sequentially formed by a flat steel rolling machine 20. FIG. 7 shows the steel plate 10 in the state before processing. FIG. 8 shows the steel plate 10 in a state in which the thick-walled portion (bulged portion) 3 and the thin-walled portions 9 at portions excluding the thick-walled portion 3 have been formed. FIG. 9 shows the steel plate in a state in which the notches 7 are further formed by vertical rolls 21. After this, the narrow-width portions 9a of the flange plate 5 are formed, and the state shown in FIG. 1 is obtained. It should be noted that the notches 7 and the narrow-width portions 9a may be formed simultaneously by making the vertical rolls 21 horizontally movable.

(23) The thick-walled portions 3, the notches 7, and the narrow-width portions 9a of the thin-walled portions 9 may be formed gradually by repeatedly performing rolling by the vertical rolls 21. Alternatively, however, the notches 7 and the narrow-width portions 9a of the thin-walled portions 9 may be formed by cutting, grinding, shaving, gas cutting processing, and the like.

Second Embodiment

(24) FIGS. 11 to 14 show a method of manufacturing a rolling formed H-shaped steel 31 for the column-beam joint structure. The thick-plate H-shaped steel 31 constituted by flange plate portions 31a and a web plate portion 31b is manufactured by an H-shaped steel rolling machine 30 after undergoing a process similar to that shown in FIGS. 7 to 10. The thick-plate H-shaped steel 31 shown in FIG. 12 is rolled into flange thick-walled portions (flange bulged portions) 33 and flange thin-walled portions 39, as shown in FIG. 13. Subsequently, notches 37 and narrow-width portions 39a are formed in the same way as the first embodiment. The beam 2 is manufactured by continuously processing a plurality of parts and is cut at cut lines 38.

(25) In the H-shaped steel 31 shown in FIG. 14, the flange thick-walled portions 33, the notches 37, and the narrow-width portions 39a of the flange thin-walled portions 39 may be formed gradually by repeatedly performing rolling. Alternatively, however, the notches 37 and the narrow-width portions 39a of the flange thin-walled portions 39 may be formed by cutting, grinding, shaving, gas cutting processing, and the like.

(26) According to the present invention, the column-beam joint parts 2b can be more uniformly and efficiently in the same way as the first embodiment. In addition, since the flange thick-walled portion (flange bulged portion) 33 is present at one end portion of the flange plate portion 31a, it is possible to obtain high weld joint strength without enlarging the width of the flange plate portion 31a.

(27) The flange plates 5 and 5a and the H-shaped steel 31 in accordance with the present invention may be formed not only by roll forming but by forging. In a case where forming is to be performed by using the flange plates 5 and 5a and the flange plate portions 31a whose outer surfaces are constant, the flange plates 5 and 5a and the flange plate portions 31a are appropriately formed by being pressurized from one side thereof.

DESCRIPTION OF REFERENCE NUMERALS

(28) 1: column-beam joint structure 2: beam 2a: column 2b: column-beam joint part 3: thick-walled portion (bulged portion) 4: web plate 5: flange plate 7: notch 9: thin-walled portion 9a: narrow-width portion 10: steel plate 20: flat steel rolling machine 21: vertical roll 22: horizontal roll 30: H-shaped steel rolling machine 31: H-shaped steel 31a: flange plate portion 31b: web plate portion