JP2015068005A - Welding joining continuous beam structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of not securing bearing force of a fill beam cross section in a beam end part, since a welding quantity is much and a beam web is pin joining, in welding joining to a girder of a bam proposed so far, while causing large deformation, when the moment applied to the beam cannot burden the bending moment of the beam end part in the pin joining of the beam end part of a conventional system, in a steel frame structure.SOLUTION: Such the various problems can reduce a beam side, by attaining manufacturing efficiency of continuous beam joining, by installing a vertical gusset (a stiffener) having a side surface shape of an inverse L shape between its girder upper-lower flanges and in a web by welding in a girder position for installing an H-shaped steel beam on an H-shaped girder, installing a C-shaped horizontal stiffener in the vertical gusset and a girder web by welding in a beam lower flange position by sandwiching the vertical gusset, welding-joining a C-shaped horizontal stiffener end part and a beam end part lower flange, and welding-joining a girder upper flange and a beam end part upper flange.

Description

The present invention mainly relates to a technique for reducing the size (dimension) of a small beam by effectively joining the large beam and the small beam in a steel building structure composed of columns, large beams, and small beams. is there. Here, a large beam is a beam that is connected to a column with a steel structure and bears earthquake, wind, floor load, etc., and a small beam is not directly connected to a column but is connected to a large beam and mainly supports the floor load. This is a beam. Rigid joining refers to joining in which the angle formed by the connections at the joining points of the material axes of the joined members does not change even after the framework is deformed by receiving an external force.

Usually, a small beam is attached to a large beam that is attached to a column of a steel structure and is rigidly connected to the column by a pin connection in a direction perpendicular to the large beam. A small beam is often used as a lateral stiffener for a large beam while supporting a floor load. This small beam is installed when the span between the large beams is large. Normally, this small beam is pre-welded to the flange and web of the large beam by welding the gusset plate, and the small beam web is bolted to this gusset plate. Yes. In this case, it is structurally a pin joint. Here, the span refers to the distance between the centers of the beams or columns.

On the other hand, several methods for attaching a small beam to a large beam have been proposed. For example, Japanese Patent Application No. 2007-22631 has a method of placing the upper flange of the small beam on the upper flange of the large beam and joining them together by fillet welding. Japanese Patent Application No. 2001-84227 has a steel beam structure in which a joint between a large beam and a small beam is rigidly connected with a high-strength bolt. In addition, a structure for joining a large beam and a small beam has been proposed, but the level (height) of the upper flange of the large beam and the small beam is almost the same.

Japanese Patent Application No. 2007-22631 Japanese Patent Application 2001-84227

As shown in FIG. 1, the side of the large beam and the end of the small beam are pin-joined, and a bending moment cannot be transmitted between the large beam and the small beam, so the bending moment is at the center in the longitudinal direction of the small beam. Concentrates and the amount of vertical deformation of the beam increases. Therefore, under a constant floor load, the pin-joint beam must use a beam member larger than the rigid-joint beam that bears the bending moment at the end. When pin joining is performed between the large beam and the small beam, the gusset plate is welded to the large beam flange and the web and used, so that the bolt member and the gusset member are increased by the gusset member and its bolt joint. Therefore, the work for attaching the gusset member and the work for joining the bolts increase. On the other hand, as shown in FIGS. 2 and 3, when the gusset plate is welded to the girder flange and the web, the gusset member and its bolt joint increase the number of bolt members and gusset members. Further, the welding amount of the large beam flange and the small beam flange is large. Moreover, the amount of on-site welding is large. Further, since the length of the small beam is determined for each interval of the large beam, the mounting material and the work amount are increased. Furthermore, as shown in FIGS. 2 and 3, even if the beam flanges of the beam are welded, the web is still pin-bonded. The bending modulus applied to the end of the beam is affected by the section modulus Z and the sectional secondary. The moment I cannot be used for the entire cross section of the beam, and it is difficult to ensure sufficient rigidity. Further, since the horizontal stiffener passes through the gusset 3, there is a problem that it takes time and labor to mount the members.

In order to reduce the deformation, weight, mounting material, number of parts, and welding amount of the beam, it is necessary to implement the following structural improvements.
1 It shall be rigidly connected to the large beam to the flange at the end of the small beam.
2 The web between the small beams is rigidly joined by welding or the like. Alternatively, the cross-section coefficient of the entire cross-section of the small beam is secured by increasing the strength of the small beam flange.
3 Reduce the amount of welding on site.
4 Reduce the vertical gusset member attached to the girder, and combine the two members divided vertically by a horizontal stiffener into one member.
5 Reduce the horizontal stiffener member.

Claim 1 will be described. In the present invention, a rigid joint structure of a steel structure large beam and a small beam is composed of the following components. First, as shown in FIG. 4, a vertical gusset (stiffener) 3 having an inverted L-shaped side surface is disposed between the upper and lower flanges 5 of the large beam at the position of the large beam where the H-shaped steel small beam 2 is attached to the H-shaped large steel beam 1. It is attached to the web 6M by welding. The thickness of this vertical gusset (stiffener) is usually greater than or equal to the beam thickness. This welding is usually performed by fillet welding, but when the plate thickness is large, groove processing is performed at the end of the vertical gusset (stiffener) 3 to reduce the welding amount. The vertical gusset 3 is usually equal to or greater than the thickness of the web 6 of the beam 2. It is a feature of the present invention that the vertical gusset (stiffener) 3 is finished with a single steel plate without dividing the upper and lower flanges 5 between the upper and lower flanges 5 above and below the horizontal stiffener 7.

Secondly, as shown in FIG. 6, a C-shaped horizontal stiffener 7 shown in FIG. 10 is welded to the vertical gusset and the large beam web with the vertical gusset 3 sandwiched between the vertical gussets at the flange position of the lower beam. Install. The length of the C-shaped horizontal stiffener 7 is about ½ of the flange width excluding the web 9 of the large beam flange 5, and the width of the C-shaped horizontal stiffener 7 is 0 to less than the width of the small beam flange attached thereto. Increase by about 50 mm. Further, the plate thickness of the C-shaped horizontal stiffener 7 is desirably one size up (3 mm) or more of the small beam flange.

Third, the end of the C-shaped horizontal stiffener 7 and the lower end 2 of the small beam 2 are welded together and the upper flange 5 of the large beam 1 and the upper flange 5 of the end of the small beam 2 are welded. Features. In this way, it is not necessary to divide the vertical stiffener or the horizontal stiffener, and the number of members is reduced, thereby reducing the number of manufacturing steps and costs.

According to a second aspect of the present invention, the planar shape of the C-shaped horizontal stiffener in the invention according to the first aspect has a quadrilateral or trapezoid outer diameter contour, and as shown in FIG. 10, this C-shaped horizontal stiffener 7 is a plan view, and a cut is provided in the center by laser cutting or the like. The cut width is about 0.5 to 3 mm larger than the plate thickness of the vertical gusset, and the cut depth is about the vertical gusset plate width. Process it. Usually, the vertical gusset plate width is set to be about 10 mm smaller than the beam flange width. FIG. 10A shows a quadrilateral planar shape of a C-shaped horizontal stiffener, and the C-shaped horizontal stiffener 7 of FIG. 10B has a planar shape that is trapezoidal and has a tapered side surface. The amount of material used can be reduced, and the amount of welding with the large beam web can be reduced. Further, the C-shaped horizontal stiffener 7 in FIG. 10 (C) is wider than the portion where the small beam flange is attached and wider than the same (A) and (B) in the direction of the small beam by 5 to 30 mm. In this part, the effect of the welding end tab can be demonstrated.

According to a third aspect of the present invention, in the invention according to the first or second aspect, as shown in FIG. 5, a bolt hole 4 is provided on the end of the inverted L-shaped vertical gusset 3 on the beam center line of the beam, and The three end portions and the small beam web 6 are bolted 4M and welded. This bolt connection is for building temporary bolts for attaching the small beam 2 to the large beam 1. This bolt connection is not sufficient to handle the shearing force due to the floor weight of the beam 2.
Therefore, when the assembly of the small beam is finished with this temporary bolt, the end of the inverted L-shaped vertical gusset 3 and the small beam web 6 are usually fillet welded. This fillet welding is performed on the gusset 3 plate side end portion and the small beam web 6 end portion side. This fillet welding bears the shear force of the floor load. In addition, the bolt hole 4 is provided on the end of the vertical gusset 3 on the beam center line (neutral line) so as not to cause a cross-sectional defect with respect to the bending moment caused by the floor load over the beam. .

The invention according to claim 4 provides the invention according to claims 1 to 3, wherein three or more bolt holes are provided in each of a tip of a vertical gusset (stiffener) having an inverted L-shaped side surface and a small beam web contacting the tip, A method of rigidly joining a large beam and a small beam by bolting the vertical gusset and the small beam web and rigidly joining the large beam and the small beam. It is a way to reduce. As shown in FIG. 6, this is an example in which four bolts are vertically arranged on the tip of a vertical gusset (stiffener) and a small beam web in contact with the tip. FIG. 6 shows a system in which a cut tee hunch is provided between the lower beam flange and the lower beam flange when the horizontal stiffening of the beam 5 is insufficient due to the beam. FIG. 7 shows a system in which a cut tee hunch is provided between the fillet portion under the large beam and the flange under the small beam when the lateral stiffening of the large beam 5 is insufficient due to the small beam alone. This method is simpler and easier than attaching the cut tee flange to the girder web.

According to a fourth aspect of the present invention, in the invention according to any one of the first to fourth aspects, as shown in FIG. 11, the dimensional position of 1/20 to 1/5 of the span between the large beam 1 and the small beam 2 from the welded joint of the large beam 1 This is a rigid joint structure of a large beam and a small beam, in which a bolt joint 4M is provided on the small beam. It is important to select the position of the bolt joint between the small beams so that the moment becomes zero due to the moment distribution of the small beam between the large beams. Since there is no moment at this position, there is an advantage that only the shear force of the floor load needs to be considered. Therefore, it is sufficient to bolt only the small beam web. In fact, if it is expected that the zero moment position will move during use of the building, it is desirable to also bolt the beam flange using a splice. In Claims 1 to 3, such a rigid connection between the small beams is mainly made by field welding at a construction site unless claim 4 is used. By using the bolted joint between the beam according to claim 4, it becomes possible to perform the rigid joint between the beam and the beam at the construction site, and the work and cost such as temporary construction and curing in the field welding are minimized. It becomes.

Claim 5 is a fishbone system, and in the invention according to claims 1 to 4, the small beam having a dimension position of 1/20 and 1/5 of the span between the large beam and the welded joint of the small beam to the large beam. It is a rigid joint structure of a large beam and a small beam that is provided with bolt joints. The end of the small beam on the large beam side is attached to the large beam at the factory, and the small beam on the large beam side and the central side beam are usually Bolts are joined on site. This bolt joint is a pin joint.

The effects of the present invention are described in the above description, but the main points are listed as follows.
The weight of the small beam can be reduced (10-30%) compared to the case of using a 1-pin large beam / small beam joint. Since the small beam can be regarded as a rigid joint on the left and right sides of the large beam, greater strength and rigidity can be obtained compared to the conventional pin joint, and the weight of the small beam can be reduced (10 to 30%).
2 Compared to the case of using a pin-jointed large beam / small beam joint, when compared with a small beam of the same beam, the maximum deformation (deflection) of the small beam is reduced to 1/5 and the maximum stress level is 2 Reduce to / 3. Since the small beam can be regarded as a rigid joint on the left and right of the large beam, the maximum deformation amount (deflection) of the small beam is reduced to 1/5 and the maximum stress degree is reduced to 2/3 as compared with the conventional pin connection.
The gussets and bolts for attaching the small beam to the large beam are significantly reduced compared to the case of using the 3 pin-bonded large beam / small beam joint. In the conventional method, a gusset with a bolt hole is attached to a large beam and is bolted to the small beam.
4. Even in comparison between conventional rigid joints, the number of members of the vertical gusset and horizontal stiffener is halved. The steel material cost can be saved accordingly.
5 Compared to conventional rigid joints, the number of bolts used on the small beam web can be reduced to about 1/4, and the bolt hole processing and bolt material cost can be reduced. So the strength is high.
7 The fishbone method can be built at the site by bolted connection even with a continuous beam structure, so it is possible to achieve a shortening of the construction period and beam reduction at the same time.

Conventional pin connection diagram of large beam and small beam Conventional butt-welded connection diagram of large beam and small beam Conventional fillet welded connection of large and small beams (Japanese Patent Application No. 2007-22631) Rigid connection diagram according to the present invention of large and small beams Explanatory drawing in which the minimum bolt hole is provided on the center of the beam and the gusset tip and the beam are welded together Example of joining a gusset tip and a small beam web with a single or multiple rows of bolt holes This is an example in which the gusset tip and the small beam web are joined by making a bolt hole in a vertical row or a plurality of rows, and the op beam flange and the small beam flange are attached with a tapered cut tee haunch. Illustration of strengthening lateral stiffening of lower half of large beam by expanding gusset lower part in continuous beam structure Installation diagram of horizontal stiffener The top view of a C-shaped horizontal stiffener, and the top view of a welding joint with the under-beam flange of a C-shaped horizontal stiffener. (A) A rectangular C-shaped horizontal stiffener, (B) a tapered C-shaped horizontal stiffener, and (C) a plan view of a welded joint of the C-shaped horizontal stiffener with the under-beam flange. Example of continuous beam structure diagram according to the present invention

Example 1
Implementation will be described with reference to FIG.
In factory production, a vertical stiffener integrated to the web is inserted into the space surrounded by the upper and lower flanges 5 and the web 6 of the large beam 1 and fillet welded thereto. Next, the cut portion of the vertical gusset 3 is inserted into the vertical gusset, and the C-shaped horizontal stiffener 7 is attached to the vertical gusset and the large beam web by welding at the lower flange position of the small beam. Two bolt holes are usually drilled in advance on the neutral axis of the beam at the tip of the vertical gusset.
At the construction site, a small beam is placed between adjacent large beams, and bolts are passed through the bolt holes that were previously opened on the neutral shaft of the small beam web and the bolt holes of the vertical gusset, and the small beams are temporarily assembled and stored. If it is good, the large beam flange and the small beam upper flange, the horizontal stiffener and the small beam lower flange are assembled and welded, and after confirming the accuracy of the steel frame, this part of the main welding is carried out. After that, fillet welding between the vertical gusset and the small beam web is performed.

Compared to the conventional pin-jointed beam method, the present invention has fewer members and welding amount, is easy to construct, and has the effect of the present invention. It can be done easily. For these reasons, the industrial applicability is high.

1 Large beam to be joined to column 2 Small beam to be joined to big beam 3 Vertical gusset plate 4 High strength bolt 4M Bolt joint (pin joint)
5 Flange 6 Web 6B Large beam web 7 Horizontal stiffener
7M Horizontal stiffener cut-out 8 Butt welding between flanges 9 Welding between gusset plate and girder 10 Rigid joint 10A Welding between horizontal stiffener (beam) and beam flange 11 Fillet welding 11B Butt welding or full penetration welding 12 Cut tee Haunch Flange 13 Cut Tee Hunch Web 14 Cut Tee Hunch Flange and Small Beam Flange Weld 15 Cut Tee Hunch Flange and Large Beam Flange Weld 16 Cut Tee Hunch Flange and Large Beam Fillet 19 Column 20 Concrete Stop 25 Assembly Weld 26 Back Welding 40 Cover plate 41 Cover plate beam side welding 42 Stiffener 43 Steel batting plate welded portion 44 Beam flange / diaphragm welded portion 45 Diaphragm 50 Bolt joint 53 Head stud 57 Floor slab 59 Earthquake Horizontal force by the floor slabs resulting from the

Claims (5)

In a steel structure, vertical gussets (stiffeners) having inverted L-shaped side surfaces are attached by welding joints between the upper and lower flanges of the large beam and the large beam web at the position of the large beam where the H-shaped steel beam is attached to the large steel beam. Then, a C-shaped horizontal stiffener is attached to the vertical gusset and the large beam web by welding joint at the position of the lower beam lower flange across the vertical gusset, and the C-shaped horizontal stiffener end and the lower beam end lower flange are connected to each other. A method for rigidly joining a large beam and a small beam, comprising welding and joining the upper beam upper flange and the small beam end upper flange. 2. The method according to claim 1, wherein the planar shape of the C-shaped horizontal stiffener is a quadrilateral or trapezoid outer diameter contour. The invention according to claim 1 or 2, wherein a bolt hole is provided on the neutral beam shaft at the end of a vertical gusset (stiffener) having an inverted L-shaped side surface, and a bolt hole is provided on the neutral beam shaft at the beam end portion web. A rigid connection structure of a large beam and a small beam, wherein the vertical gusset and the small beam web are bolted and further welded to each other. Method In the invention according to claims 1 to 3, three or more bolt holes are respectively provided in the tip of a vertical gusset (stiffener) having an inverted L-shaped side surface and a small beam web contacting the tip, and the vertical gusset and the A method for rigidly joining a large beam and a small beam, wherein the large beam and the small beam are rigidly joined by bolting the small beam web. The invention according to claim 1 to 4, characterized in that a bolt joint is provided on the small beam having a size position of 1/20 and 1/5 of the span between the large beam and the welded joint between the large beam and the small beam. Rigid connection structure of beam and beam