JP7794535B2 - Steel beam joining method - Google Patents

Description

The present invention relates to a method for joining steel beams.

The steel frame structure that makes up a steel-framed (S (Steel) construction) building is formed by bridging main girders (G (Girder) beams) across brackets formed from H-shaped steel beams that extend from columns and other structures, with sub-girders (B (Beam)) spanning between opposing main girders as needed. In more detail, other structural components of the steel frame include cantilever beams (CG (Cantilever Girder) beams, CB (Cantilever Beam) beams) that form the cantilever structure of the building, and underground beams (FG (Footing Girder) beams) that form the foundation.

For example, in construction where a steel beam, also made of H-shaped steel, is hung over a bracket made of H-shaped steel projecting from a steel column, the end of the steel beam, which is lifted and transported by a crane or similar device, is positioned to the side of the bracket and the two are joined. It is common for temporary shoring to be installed to temporarily support the steel beam. The steel beam temporarily supported on the temporary shoring and the bracket are then bolted together with high-strength bolts (high-tension bolts) via splice plates, after which the temporary shoring is dismantled and removed. Installing and dismantling this temporary shoring takes time and effort, and this issue becomes even more pronounced as the size of the building increases and the number of steel beams being erected increases.

For these reasons, when joining steel beams made of H-shaped steel to other H-shaped steel components (such as brackets extending from steel columns or separate steel beams) during the construction of steel frames, a joining structure and joining method for steel beams that eliminates the need for temporary support structures is desirable.

Patent Document 1 proposes a steel beam joint structure in which the ends of steel beams, each consisting of a web and a flange, are joined together. Specifically, the structure comprises a plate-shaped joint member fixed to the area where the end of the upper flange on the joined side of each steel beam and the upper part of the continuous web have been removed, with its upper surface continuing onto the upper surface of the upper flange. Splice plates are attached to both sides of the web on the underside of each joint member, spanning both joint members, and multiple bolts and nuts fasten the splice plates to each joint member. The joint members are made of plate material thicker than the upper flange. On both sides of the web on the upper part of this joint member, recesses are provided that are deeper than the height of the bolt heads and wider than the diameter of the heads, and multiple insertion holes are drilled downward from the bottom of these recesses for inserting the bolt shanks. The splice plate has through holes that correspond to the insertion holes, and the through holes in the joint members are aligned with the through holes in the splice plate, and a bolt is inserted from the through-hole side, with its head fitting into the recess and its tip extending below the splice plate, and then tightened with a nut.

Japanese Patent Application Publication No. 6-173340

The steel beam joint structure described in Patent Document 1 allows the flanges of the H-shaped steel beams that form the top surface of the girder to be joined together without welding, making it possible to flatten the top surfaces of the interconnected flanges. However, even when constructing this joint structure, the installation of the temporary support structure described above is still required.

The present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for joining steel beams that eliminates the need for temporary support when joining two steel beams made of H-shaped steel during the construction of a steel frame structure.

In order to achieve the above object, one aspect of the steel beam joint structure according to the present invention is as follows:
A joint structure of two steel beams formed by H-shaped steel having a web, an upper flange, and a lower flange,
The ends of the webs of the two steel beams are provided with first and second step portions that engage with each other, and the second step portion is placed on top of the first step portion and engages with the first step portion;
The web, the upper flange, and the lower flange of each of the steel beams are connected by bolts via a splice plate.

In this aspect, the two steel beams to be joined together have first and second stages that engage with each other. By placing the second stage on top of the first stage and engaging them during erection, the other steel beam with the second stage can be erected without the need for temporary shoring, eliminating the need for temporary shoring.

Here, in steel beams with a first step, the end of the upper flange is set back further inward (away from the end) than the end of the lower flange to match the first step, and in steel beams with a second step, the end of the lower flange is set back further inward than the end of the upper flange to match the second step.

In addition, the two steel beams that are joined to each other may be in a form in which the steel beam with the first stage is a bracket that forms the column-beam joint, and the steel beam with the second stage is a beam that is joined to the bracket, or in a form in which a long steel beam is formed from multiple divided steel beams and the beams are two beams that are joined to each other.

The first and second sections are engaged with each other, allowing the engaging sections to bear part of the shear force. In conventional structures, the bolts connecting the webs of the two H-shaped steel beams via a splice plate bear the entire shear force. However, in this configuration, the engaging sections of the webs bear part of the shear force, making it possible to reduce the number of bolts connecting the webs.

In another aspect of the joint structure of the steel beam according to the present invention,
The steel beam having the first step portion is a bracket extending from a steel column,
The steel beam having the second step portion is characterized in that it is a beam installed between two steel beams that are erected at an interval.

In this embodiment, the second section of the beam rests on the first section of the bracket extending from the steel column, engaging the two, making it possible to erect a steel beam on the steel column without the need for temporary support. Here, when joining a bracket to a beam, for example, if one steel beam is erected on each bracket extending from two steel columns spaced apart by a centerline distance, the steel beam has second sections at both ends, and by erecting both second sections on the first sections of the corresponding brackets, an erection position can be formed in which the beam is supported by two brackets. A steel beam joining structure is then formed on each end of the beam.

In another aspect of the joint structure of the steel beam according to the present invention,
The bolted joint is characterized by using high-strength bolts.

In this embodiment, the steel beams are joined together using high-strength bolts via splice plates, creating a joint structure with high joint strength.

In addition, one aspect of the joining method for steel beams according to the present invention is to
A method for joining two steel beams formed by H-shaped steel beams having a web, an upper flange, and a lower flange, comprising:
The ends of the webs of the two steel beams are provided with first and second step portions that engage with each other,
placing the second step portion of one of the steel beams on the first step portion of the other steel beam and engaging them together;
The webs, the upper flanges, and the lower flanges of both steel beams are connected by bolts via splice plates.

In this aspect, the two steel beams to be joined together have first and second stages that engage with each other. By placing the second stage on top of the first stage and engaging them during erection, the other steel beam with the second stage can be erected without the need for temporary shoring, eliminating the need for temporary shoring.

In another aspect of the joining method for steel beams according to the present invention,
The steel beam having the first step portion is a bracket extending from a steel column,
The steel beam having the second step portion is a beam installed between two steel beams that are erected at an interval,
The splice plate is temporarily joined to the upper flange of the end of the beam in advance,
When the second step portion is placed on the first step portion and the two are engaged with each other, the splice plate is engaged with the upper flange of the bracket.

In this embodiment, by temporarily joining a splice plate to the upper flange of the end of a beam that has a second step, when the beam is erected on the bracket, the second step is placed on top of the first step and the two are engaged. Furthermore, when the beam is in this engaged position, the splice plate that is temporarily joined to the beam is locked onto the upper flange of the bracket, allowing for an even more stable erection position of the beam on the bracket without the need for temporary support.

In another aspect of the joining method for steel beams according to the present invention,
The splice plate is temporarily joined to the upper flange by bolting using ordinary bolts;
The main joining of the web, the upper flange, and the lower flange to the splice plate is performed by bolting using high-strength bolts.

According to this aspect, the splice plate is temporarily joined to the top flange of the beam using standard bolts. This allows for quick removal of the splice plate when erecting the beam on the bracket, for example, if the splice plate interferes with other components. Furthermore, the final joining of the top flange, bottom flange, and web to the splice plate is performed using high-strength bolts, creating a steel beam joint structure with high joint strength.

As can be understood from the above explanation, according to the method for joining steel beams of the present invention, temporary support work can be eliminated when joining two steel beams made of H-shaped steel during the construction of a steel frame structure.

1 is a process diagram illustrating an example of a method for joining steel beams according to the first embodiment. FIG. 1 , and is a process diagram illustrating an example of a method for joining steel beams according to the first embodiment. 2 , this is a process diagram illustrating an example of a method for joining steel beams according to the first embodiment, and further illustrates an example of a joining structure of steel beams according to the embodiment. FIG. 10 is a process diagram illustrating an example of a method for joining steel beams according to the second embodiment. 4A to 4C are process diagrams illustrating an example of a method for joining steel beams according to the second embodiment.

Below, examples of steel beam joining methods and steel beam joining structures according to each embodiment will be described with reference to the accompanying drawings. Note that in this specification and drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description.

[Method for joining steel beams according to the first embodiment and joining structure of steel beams according to the embodiment]
First, a method for joining steel beams according to a first embodiment and an example of a joining structure for steel beams according to the embodiment will be described with reference to Figures 1 to 3. Figures 1 to 3 are process diagrams illustrating an example of a joining method for steel beams according to the first embodiment, and Figure 3 is a diagram further illustrating an example of a joining structure for steel beams according to the embodiment.

The two steel beams joined using the joining method in the illustrated example are the bracket 10 and beam 20 that make up the beam-column joint 70, but the joining method according to the embodiment may also be applied to other situations, such as joining split beams when a long beam is made up of multiple split beams.

As shown in Figure 1, a bracket 10 (an example of a steel beam) is welded to the side of a steel column 30 formed from a square steel pipe, forming a beam-column joint 70.

The bracket 10 is formed from an H-shaped steel beam with a web 11, an upper flange 12, and a lower flange 13, each with multiple bolt holes 11a, 12a, and 13a drilled in the wide sides. The upper flange 12 and the lower flange 13 are joined to the side of the steel column 30 by, for example, butt welding, and the web 11 is joined by, for example, fillet welding.

On the other hand, the other steel beam joined to the bracket 10 is a beam 20 (an example of a steel beam) that is erected on each bracket 10 extending from two steel columns 30 that are erected with a center-to-center distance between them, as shown in Figure 2.

The beam 20 is formed from an H-shaped steel beam with the same dimensions and specifications as the bracket 10, and multiple bolt holes 21a, 22a, and 23a are drilled in the wide surfaces of the web 21, upper flange 22, and lower flange 23.

Returning to Figure 1, a first step 15 is provided at the end of the web 11 of the bracket 10. To match the first step 15, the end of the upper flange 12 is set back further inward on the bracket 10 (towards the steel column 30) than the end of the lower flange 13.

On the other hand, a second step 25 is provided at the end of the web 21 of the beam 20, which is placed on the first step 15 in the X direction when the beam 20 is erected on the bracket 10. To match the second step 25, the end of the lower flange 23 is set back further inward on the beam 20 (opposite the steel column 30) than the end of the upper flange 22.

As shown in Figure 2, a beam 20 is suspended by a crane (not shown) and dropped from above onto each bracket 10 extending from two steel columns 30 spaced apart along the centerline. This causes the second step portions 25 at both ends of the beam 20 to rest on the first step portion 15 of each bracket 10, and the first step portions 15 and second step portions 25 engage to form engagement portions 80, stably supporting the beam 20 against the left and right brackets 10.

Next, as shown in Figure 3, splice plates 40A are placed on the left and right sides of the webs 11, 21 of both the bracket 10 and the beam 20 (Figure 3 shows only one splice plate 40A), and the two are finally joined using high-strength bolts 51 and nuts 52.

Furthermore, a splice plate 40B is placed above both upper flanges 12, 22 and joined together with high-strength bolts 51 and nuts 52, and a splice plate 40C is placed below both lower flanges 13, 23 and joined together with high-strength bolts 51 and nuts 52, thereby forming a joint structure 100 between the bracket 10 and the beam 20 at the column-beam joint 70 of the two steel columns 30.

According to the illustrated method of joining steel beams, the two steel beams 10, 20 to be joined have a first step 15 and a second step 25 that engage with each other. During erection, the second step 25 is placed on top of the first step 15 and the two are engaged, allowing the steel beam 20 with the second step 25 to be erected on the steel beam 10 without the need for temporary shoring, thus eliminating the need for temporary shoring.

Furthermore, because the first step 15 and the second step 25 are engaged with each other, the engaging portion 80 can bear a portion of the acting shear force. For example, in a conventional structure that does not have an engaging portion, the bolts that connect the webs of the two H-shaped steel beams to each other via a splice plate bear the entire shear force. However, in the illustrated joining structure 100, the engaging portion 80 of the webs 11, 21 bears a portion of the shear force, making it possible to reduce the number of bolts 51 connecting the webs 11, 21.

[Method for joining steel beams according to the second embodiment]
Next, an example of a method for joining steel beams according to the second embodiment will be described with reference to Fig. 4, Fig. 5, and Fig. 3. Here, Fig. 4 and Fig. 5 are process diagrams illustrating an example of a method for joining steel beams according to the second embodiment, respectively.

The beam 20 shown in Figure 4 has a splice plate 40B temporarily joined to the upper surface of the end of the upper flange 22.

Here, temporary joining refers to joining the splice plate 40B using ordinary bolts 61 and nuts 62 in an easily removable manner, as opposed to a permanent joining using high-strength bolts 51. From the perspective of easily removable, temporary joining may also include spot welding and the like.

As shown in Figure 5, when the beam 20 is dropped from above onto each of the brackets 10 extending from two steel columns 30, the second step portions 25 at both ends of the beam 20 rest against the first step portion 15 of each bracket 10, and the first step portions 15 and second step portions 25 engage to form engagement portions 80. In addition, a portion of the splice plate 40B extending from the upper flange 22 of the beam 20 is engaged with the upper flange 12 of the bracket 10.

In this way, the engagement portion 80 formed by the first step 15 and second step 25 of the webs 11, 21 of both the bracket 10 and the beam 20, and the splice plate 40B temporarily joined to the beam 20, locks onto the bracket 10, allowing the beam 20 to be erected more stably on both brackets 10 without the need for temporary support.

Here, if the splice plate 40B protruding laterally interferes with other components (not shown) when the beam 20 is lowered, the splice plate 40, which is temporarily joined with ordinary bolts 61, can be quickly removed, eliminating the risk of delays in erection work.

After the beam 20 is stably installed on the left and right brackets 10 as shown in Figure 5, the ordinary bolts 61 are removed, and other splice plates 40A, 40C are installed as shown in Figure 3. The splice plates 40A, 40B, 40C are then fully joined using high-strength bolts 51 and nuts 52 via each splice plate. This forms a joint structure 100 between the brackets 10 and the beam 20 at the beam-column joint 70 of the two steel columns 30.

Other embodiments may be possible in which other components are combined with the configurations described in the above embodiments, and the present invention is in no way limited to the configurations shown here. In this regard, changes can be made without departing from the spirit of the present invention, and can be determined appropriately depending on the application form.

10: Steel beam (bracket)
11: Web 11a: Bolt hole 12: Upper flange 12a: Bolt hole 13: Lower flange 13a: Bolt hole 15: First stage 20: Steel beam (beam)
21: Web 21a: Bolt hole 22: Upper flange 22a: Bolt hole 23: Lower flange 23a: Bolt hole 25: Second step 30: Steel column 40A, 40B: 40C: Splice plate 51: High-strength bolt 52: Nut 61: Ordinary bolt 62: Nut 70: Column-beam joint 80: Engagement portion 100: Joint structure of steel beam (joint structure)

Claims (1)

A method for joining steel beams, comprising the steps of: joining a first steel beam and a second steel beam, both of which are formed by H-shaped steel beams each having a web, an upper flange, and a lower flange; joining the first steel beam to a column in advance; and joining the second steel beam to the first steel beam,
the first steel beam is a bracket extending from a steel column;
The second steel beam is a beam installed between the two steel columns that are erected at an interval,
the first steel beam and the second steel beam have end portions of the webs each having a first step portion and a second step portion that engage with each other;
The first step and the second step are formed by straight lines parallel to the longitudinal direction of the H-shaped steel,
A splice plate is temporarily joined to the upper flange of the end of the beam using ordinary bolts in advance,
The beam is lowered, and the second step portion is placed on the first step portion to engage them together. At this time, the upper flange and the lower flange of the first steel beam are engaged with the upper flange and the lower flange of the second steel beam at their flat surfaces, respectively , and the splice plate is engaged with the upper flange of the first steel beam.
The webs, the upper flanges, and the lower flanges of the first steel beam and the second steel beam are each permanently joined by bolt connections using high-strength bolts via a plurality of splice plates , and when this permanent joining is performed, the ordinary bolts are removed from the temporarily joined locations, and the permanent joining is performed by bolt connections using the high-strength bolts.
A method for joining steel beams, characterized in that the ordinary bolt is a means for removing one of the temporarily joined splice plates from the beam and continuing erection construction if the splice plate interferes with another member when the beam is being lowered, thereby preventing construction delays .