WO2018143622A1

WO2018143622A1 - Steel frame structure having earthquake-resistant intermediate moment joint part

Info

Publication number: WO2018143622A1
Application number: PCT/KR2018/001220
Authority: WO
Inventors: 주영규; 도병호; 박만우
Original assignee: 동부제철 주식회사; 고려대학교 산학협력단
Priority date: 2017-01-31
Filing date: 2018-01-29
Publication date: 2018-08-09
Also published as: KR20180089145A

Abstract

Disclosed is a steel frame structure having an earthquake-resistant intermediate moment joint part, the structure comprising: columns for supporting a building; beams joined to the columns by joint parts in a direction traversing the columns; a first plastic hinge part at which the moment-of-inertia capacity of the beam is reduced in the direction of being apart from the joint part of the beam; and a second plastic hinge part at which the moment-of-inertia capacity of the beam is reduced in the direction of being apart from the first plastic hinge part at the joint part. Therefore, even if the intermediate moment structure is implemented, the depth of the beam can be further increased such that application to a building which requires a long span is enabled and the total amount of steel frames reduced.

Description

Steel structure with seismic middle moment connection

The present invention relates to a steel structure, and more particularly, to a steel structure having an intermediate moment joint with enhanced seismic performance.

Moment frame is widely used as lateral force resistance system of steel structure. These moment frames are to be ductile at the joints by bending yield of beams and shear yield of panel zones. Therefore, each element of well-formed moment frame joints must undergo many plastic deformations while exhibiting the required strength during an earthquake. In fact, through many experiments in the 1960s and 1970s, steel moment frames were considered to be the best lateral resistance system.

However, during the Northridge (1994) earthquake, unexpected brittle fracture occurred at the steel moment frame joint. In order to solve this problem, the SAC Project was conducted in the United States to identify various causes affecting the performance of steel moment frame joints, as well as new details such as reduced beam section (RBS) joints, haunt joints, and rib joints. It has been developed and subsequently reflected in various building structural standards (KBC, ANSI / AISC, FEMA).

Under current standards, moment frames that can be used for seismic design are classified into general moment frames, intermediate moment frames, and special moment frames. The choice of these frames is determined by the seismic risk and earthquake design category of the area where the building will be located. do.

When the column-beam connection is recognized as intermediate moment frame or special moment frame, the seismic response coefficient is applied at the time of design reflection, and as a result, the shear stress applied to the design is reduced, which reduces the overall volume of the building. There is this. In order to be recognized as an intermediate moment frame in the Korean Architectural Structural Standards (KBC 2016), the beam-column joints must be capable of exhibiting at least 0.02 rad of interlaminar displacement angle, and the beam dances greater than 750 mm when the joints specified in the standard are used. It is prescribed that we cannot do it. In addition, it is specified that the joining plate of the beam-column joint must be welded at the pole and the factory. This is to prevent the joint from breaking before the other part of the beam is plastically deformed by an appropriate amount.

However, when the dance of the beam is limited to less than 750mm, not only is it difficult to implement a long span structure, but also increases the thickness of the flange of the beam, there is a disadvantage that the total steel frame volume increases.

In addition, when welding the joining plate to the beam in the factory, there is a disadvantage that there is a difficulty in the process management, such as the logistics cost is rapidly increased when the transfer from the factory to the site is very difficult.

Embodiment of the present invention is devised to solve the above problems, by increasing the plastic rotation capacity of the joint portion, it is possible to reduce the load on the joint portion of the column and the beam, it is possible to further increase the dance of the beam In addition, it is possible to facilitate the coupling of the joint more, it is possible to reduce the amount of steel, and to provide a steel structure having a seismic middle moment joint easier to transfer.

Embodiment of the present invention, in order to solve the above problems, pillars for supporting the building; A beam joined by a joint to the column in a direction crossing the column; A first plastic hinge portion in which the cross-sectional moment performance of the beam is reduced in a direction away from the junction of the beam; And a second plastic hinge portion in which the cross-sectional moment performance of the beam is reduced in a direction spaced apart from the first plastic hinge portion at the joint portion.

Here, the cross-sectional moment performance of the second plastic hinge portion is preferably smaller than the first plastic hinge portion.

The cross-sectional moment performance of the second plastic hinge portion and the first plastic hinge portion is effectively formed so that plastic deformation occurs at the same time by the load applied to the steel structure.

Preferably, the width of the flange of the first plastic hinge portion is smaller than the flange width of the beam of the joint portion.

It is effective that the flange width of the first plastic hinge portion is reduced in a curved shape.

The flange width of the first plastic hinge portion may be implemented to be reduced to a straight shape.

Preferably, the flange width of the second plastic hinge portion is smaller than the flange width of the joint portion.

It is effective that the flange thickness of the second plastic hinge portion is thinner than the flange thickness of the first plastic hinge portion.

The flange of the second plastic hinge portion, which is thinner than the flange of the first plastic hinge portion, is joined to the side surface of the flange of the first plastic hinge portion.

Alternatively, a bottom flange may be integrally formed across the coupling part, the first plastic hinge part, and the second plastic hinge part, and an upper flange may be disposed over an upper surface of the coupling part and the first plastic hinge part of the bottom flange. May be combined.

Meanwhile, the strength of the flange of the second plastic hinge part is weaker than that of the flange of the first plastic hinge part, and the thickness may be the same.

According to the problem solving means of the present invention as described above it can be expected a variety of effects including the following matters. However, the present invention is not achieved by exerting all of the following effects.

The height of the dance of the beam can be further increased by configuring the first hinge portion and the second hinge portion that are plastically deformed near the beam and column junction. Therefore, not only can be applied to the building requiring a long span, there is an advantage that can reduce the total amount of steel.

In addition, there is an advantage that the stress applied to the joint is less, and the shape or condition of the joint can be made more free.

1 is a perspective view of a joint of a steel structure of a first embodiment of the present invention

2 is a plan view of FIG. 1

3 is a side view of FIG. 1

4 is a graph showing the required moment and the actual moment performance of the beam required along the longitudinal direction of the beam when a uniform load is applied to the beam of FIG.

FIG. 5 is a diagram conceptually illustrating deformation of a beam when an earthquake load is applied to FIG. 1; FIG.

FIG. 6 is a diagram illustrating a finite element analysis result in a state in which an earthquake is applied to a time point when destruction occurs in FIG. 1. FIG.

FIG. 7 is a graph measuring a time point at which fracture occurs by gradually and repeatedly applying an interlayer deformation load to the steel structure of FIG. 1.

Figure 8 is a perspective view of the joint portion of the steel structure of the second embodiment of the present invention

9 is a top view of FIG. 8

10 is a side view of FIG. 8

FIG. 11 is a graph measuring a time point at which fracture occurs by gradually and repeatedly applying an interlayer deformation load to the steel structure of FIG. 8.

12 is a perspective view of a joint of a steel structure of a third embodiment of the present invention

FIG. 13 is a plan view of FIG. 12.

14 is a side view of FIG. 12.

Figure 15 is a perspective view of the joint portion of the steel structure of the fourth embodiment of the present invention

FIG. 16 is a top view of FIG. 15

17 is a side view of FIG. 15

FIG. 18 is a graph measuring a time point at which fracture occurs by gradually and repeatedly applying an interlayer deformation load to the steel structure of FIG. 15.

19 is a perspective view of the steel structure joint portion of the fifth embodiment of the present invention

20 is a graph measuring a time point at which fracture occurs by gradually and repeatedly applying an interlayer deformation load to the steel structure of FIG. 19.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

1 is a perspective view of an intermediate moment joint of the steel structure of the first embodiment of the present invention, Figure 2 is a plan view of Figure 1, Figure 3 is a side view of FIG.

As shown in these drawings, the steel frame structure having the seismic middle moment joint of the first embodiment of the present invention includes a pillar 100 supporting a building and the pillar 100 in a direction crossing the pillar 100. And the first plastic hinge 410 in which the cross-sectional moment performance of the beam 300 is reduced in a direction spaced apart from the joint portion of the beam 300 by the joining part 200. And a second plastic hinge part 420 having a reduced cross-sectional moment performance of the beam 300 in a direction spaced apart from the first plastic hinge part 410 at the joint part 200.

Here, "cross-sectional moment performance" refers to the ability to withstand the moment load, depending on the material properties of the member and the shape of the cross section. In other words, the cross-sectional moment performance is affected by the cross-sectional secondary moment according to the cross-sectional shape and the material properties of the member.

The pillars 100 are installed to support the building on a foundation, and a plurality of pillars are installed at intervals as necessary. In general, the pillars 100 are welded in a direction transverse to both ends of the web 110 and the web 100. The 'H' type member with cross section is used. However, the shape of the pillar may be variously formed according to the needs of the building.

The beam 300 has a web 310 and a flange 320 welded in a direction transverse to both ends of the web 310, similarly to the pillar. However, the flange 320 of the beam 300 is changed in shape in the direction away from the junction 200. That is, the flange 320 has a thickness between the first flange 320a adjacent to the junction, the second flange 320b connecting the first flange 320a, and the width of the flange gradually decreases, and the thickness of the second flange 320b. Is a third flange 320c of the gradually thinning section, and a fourth flange 320d in contact with the third flange 320c and uniformly formed with the same thickness and width as the thinned thickness of the three flanges 320c. . That is, the flange 320 of the beam is formed so that the flange width is reduced in a curved shape in the second flange (320b) on the basis of the joint, the thickness of the flange is thin in the third flange (320c).

The junction 200 includes a joint plate 210 bolted to and welded to the web 310 of the beam, welded to the column flange 120, and a reinforcement plate 230 welded between the flange and the flange of the column. Doing.

FIG. 4 is a graph showing the required moment required for the beam along the longitudinal direction of the beam and the actual moment performance of the beam when a uniform load is applied to the beam of FIG. 1.

The required moment D shows the magnitude of the moment applied to the actual beam by the load, and the cross-sectional moment performance C shows the amount of moment that the beam can support according to the change in the cross section of the beam. The plastic hinge part is a site where plastic deformation occurs when an excessive load is applied, and occurs in the point where the required moment (D) graph and the cross-sectional moment performance (C) graph meet in FIG. 4.

As shown in FIG. 4, the first plastic hinge portion 410 is formed at one point of the second flange 320b having the reduced width of the flange, and the third flange 320c and the fourth flange 320d are formed. The second plastic hinge portion 420 is formed at the junction of the).

In this case, the cross-sectional moment performance of the second plastic hinge part 420 is smaller than that of the first plastic hinge part 410. More preferably, the cross-sectional moment performance of the second plastic hinge portion is smaller than the cross-sectional moment performance of the first plastic hinge portion with a difference in the degree of contact with the required moment D at the same time, so that plastic deformation may occur at the same time. It is possible to increase the plastic deformation amount.

The width of the flange 410 of the first plastic hinge portion is formed to be smaller than the flange width of the beam of the junction portion 200, the flange width of the first plastic hinge portion 410 is formed to be reduced in a curved shape. Since the width of the flange of the first plastic hinge portion 410, that is, the width of the flange of the second flange 320b is reduced to a curved shape, there is an advantage that the cross-sectional moment performance (c) can be prevented from changing rapidly.

The flange thickness of the second plastic hinge part 420 is formed to be thinner than the flange thickness of the first plastic hinge part 410, and the flange width of the second plastic hinge part 420 is the flange width of the joint part 200. It is formed smaller. That is, as shown in FIG. 2, by narrowing the flange width of the fourth flange 320d, it is possible to prevent the thickness of the fourth flange 320d necessary for plastic deformation from being sharply reduced. As a result, there is an advantage that the flange thickness appropriate to the load on the fourth flange (320d) can be secured.

The second plastic hinge part 420 may be implemented by abutting the flange of the second plastic hinge part thinner than the flange of the first plastic hinge part toward the side of the flange of the first plastic hinge part. That is, the first flange 320a and the second flange 320b in which the first plastic hinge part 410 is formed are formed in one thick plate, and the fourth flange 320d in which the second plastic hinge part 420 is formed. After forming into a thin plate, it can be formed by welding.

Alternatively, the bottom flange is integrally formed with the coupling part 200, the first plastic hinge part 410, and the second plastic hinge part 420, and the coupling part 200 and the bottom flange are integrally formed. An upper flange may be coupled to the upper surface of the first plastic hinge 420. That is, the flange may be formed by fixing the upper flange to overlap the upper surface of the bottom flange having a thickness corresponding to the second plastic hinge portion 420 so as to form a thickness of the first flange and the second flange. have.

FIG. 5 is a diagram conceptually illustrating deformation of a beam when an earthquake load is applied to FIG. 1.

By forming two or more plastic hinge parts as mentioned above, as shown in FIG. 5, an interlayer displacement angle can be exhibited even without many deformation | transformation in the junction part 200, and it can prevent that a junction part is destroyed. That is, the dance of the beam of the junction part 200 becomes high, and the deformation | transformation of a junction part can exhibit the at least enough interlayer displacement angle.

In addition, since many deformations must occur at the joint in the past, in order to prevent breakage at the joint in the process, the welding conditions of the joint and the voids that may affect the cross-sectional moment performance have been strictly regulated. However, in the embodiment of the present invention, since the amount of plastic deformation burdened by the joint is very small, there is an advantage that the fracture does not occur even if this strict standard is not applied.

FIG. 6 is a finite element analysis result of applying a seismic load to the time point of failure in FIG. 1.

As shown in FIG. 6, when an extreme earthquake load is applied, a point at which fracture or buckling occurs is a second hinge point, and it can be confirmed that low stress is generated at the junction.

Therefore, as in the prior art, the welding plate 210 may be welded in the field without welding the pole and the factory, and for this reason, there is an advantage that the cost required for the logistics of the pole may be greatly reduced.

At this time, the dance of the beam was measured in the state of 1200mm. As can be seen in Figure 7, the steel structure of the first embodiment of the present invention, even though the dance of the beam is 1200mm far exceeding 750mm, even if the interlaminar deformation amount is 2% or more, the fracture does not occur, 3% Generated, it can be confirmed that there is sufficient seismic capacity.

As described above, according to the first embodiment of the present invention, the height of the dance of the beam can be further increased by configuring the first hinge part and the second hinge part which are plastically deformed near the beam and column joint part. Therefore, not only can be applied to buildings requiring long span, but also has the advantage of reducing the total amount of steel.

A characteristic of the present invention is that the above-described first plastic hinge portion 410 and the second plastic hinge portion 420 are formed to be spaced apart from the beam 300. If necessary, three or more plastic hinge portions may be formed, which is naturally within the scope of the present invention.

8 is a perspective view of the joint of the steel structure of the second embodiment of the present invention, Figure 9 is a plan view of Figure 8, Figure 10 is a side view of FIG.

The steel structure of the second embodiment is different from the first embodiment in that the widths of the remaining flanges are the same except for the portion where the first plastic hinge portion 410 is formed, and the rest of the structure is the same.

That is, the beam 1300 includes a web 1310 and a flange 1320 welded in both directions across the web 1310. However, the flange 1320 of the beam 1300 is changed in shape in the direction away from the junction 200. That is, the flange 1320 has a thickness between the first flange 1320a adjacent to the junction, the second flange 1320b connecting the first flange 1320a, and the width of the flange gradually decreases, and the thickness of the second flange 1320b. The third flange 1320c of the section gradually thinning, and the fourth flange (1320d) in contact with the third flange 1320c and uniformly formed with the same thickness and width as the thinner thickness of the three flanges 1320c. . That is, the flange 1320 of the beam is formed so that the flange width is reduced in a curved shape in the second flange 1320b on the basis of the joint, and the thickness of the flange is thin in the third flange 1320c.

However, unlike the first embodiment, the flange widths of the surfaces of the second flange 1320b and the surface of the second flange 1320b that are joined to the third flange 1320c are the same, and the third flange 1320c and the fourth flange are the same. The flange width of 1320d is also formed in the same manner as the joint portion.

Since the rest of the configuration is the same as in the first embodiment, detailed description thereof will be omitted.

The steel frame structure of the second embodiment has an advantage that the quantity is increased compared to the first embodiment, but is much easier to manufacture.

At this time, the dance of the beam was measured in the state of 1200mm. As can be seen in Figure 11, the steel structure of the second embodiment of the present invention, even though the dance of the beam is 1200mm far exceeding 750mm, even if the interlaminar deformation amount is 2.5% or more, there is sufficient seismic capacity can confirm.

12 is a perspective view of a joint of a steel frame structure according to a third embodiment of the present invention, FIG. 13 is a plan view of FIG. 12, and FIG. 14 is a side view of FIG. 12.

Steel Structure of Third Embodiment In the second embodiment, the rest of the configuration is the same except that the flange width of the first plastic hinge portion 410 is reduced in a straight line shape.

That is, the beam 2300 includes a web 2310 and a flange 2320 welded in a direction crossing both ends of the web 2310. However, the flange 2320 of the beam 2300 is changed in shape in the direction spaced apart from the junction 200. That is, the flange 2320 is the first flange 2320a adjacent to the junction, the second flange (2320b) and the second flange (2320b) thickness is in contact with the first flange 2320a, the width of the flange is gradually smaller The third flange 2320c of the section gradually thinning, and the fourth flange 2320d, which is uniformly formed with the same thickness and width as the thinned thickness of the three flanges 2320c, in contact with the third flanges 2320c. . That is, the flange 2320 of the beam is formed so that the flange width is reduced in a straight line shape in the second flange (2320b) on the basis of the joint, the thickness of the flange is thinner in the third flange (2320c).

However, unlike the first embodiment, the flange widths of the surfaces of the second flange 2320b connected to the joint portion of the second flange 2320b and the surfaces of the second flange 2320b are the same, and the third flange 4320c and the fourth flange are the same. The flange width of 2320d is also formed in the same manner as the joint portion.

Since the rest of the configuration is the same as in the second embodiment, detailed description thereof will be omitted.

Compared to the first embodiment, the steel frame structure of the third embodiment is increased in quantity, but has an advantage of being much easier to manufacture. In particular, by forming the second flange 2320b in a straight line, there is an advantage that the manufacturing is easier than in the second embodiment.

15 is a perspective view of a joint of a steel frame structure according to a fourth embodiment of the present invention, FIG. 16 is a plan view of FIG. 15, and FIG. 17 is a side view of FIG. 15.

As shown in these figures, the steel frame structure of the fourth embodiment shows that four plastic hinge portions are formed. The steel frame structure of the fourth embodiment is implemented by the flange 3320 of the beam 3300 having two structures of the first embodiment successively formed. That is, the portion denoted by A in FIG. 15 is the same as the flange 320 of the beam of the first embodiment, and the portion denoted by B which is the same as the flange 320 of the beam of the first embodiment is subsequently connected.

As a result, the plastic hinge part includes a first plastic hinge part 410, a second plastic hinge part 420, a third plastic hinge part 430, and a fourth plastic hinge part 440.

FIG. 18 is a graph illustrating a time point at which fracture occurs by gradually and repeatedly applying an interlayer deformation load to the steel structure of FIG. 15.

At this time, the dance of the beam was measured in the state of 1200mm. As can be seen in Figure 18, the steel structure of the fourth embodiment of the present invention, even though the dance of the beam is 1200mm far exceeding 750mm, even if the interlaminar deformation amount is 3% or more, there is sufficient seismic capacity can confirm.

19 is a perspective view of the steel structure joint portion of the fifth embodiment of the present invention.

In the fifth embodiment of the present invention, the steel frame structure is characterized in that the strength of the flange of the second plastic hinge portion 420 is weaker than the strength of the flange of the first plastic hinge portion 410, the thickness is the same. That is, the material properties of the flange 4320a in which the first plastic hinge part 410 is reduced and the flange 4320b in which the second plastic hinge part 420 is formed are different, but the thickness thereof is the same. It is characterized by. By forming the flange 4320a in which the first plastic hinge part 410 is formed of a material having a stronger strength than the other parts, the cross-sectional moment performance is different, so that the second plastic hinge part 420 is formed.

FIG. 20 is a graph illustrating a time point at which fracture occurs by gradually and repeatedly applying an interlayer deformation load to the steel structure of FIG. 19.

At this time, the dance of the beam was measured in the state of 1200mm. As can be seen in Figure 20, the steel structure of the fifth embodiment of the present invention, even though the dance of the beam is 1200mm far exceeding 750mm, even if the interlaminar deformation amount is 2% or more, the fracture does not occur, 3% Generated, it can be confirmed that there is sufficient seismic capacity.

The fifth embodiment has the advantage that the upper surface is uniform throughout the entire section from the junction to the beam, the space utilization is much easier.

As described above, the feature of the present invention is characterized in forming two or more plastic hinges on the beam. Therefore, it is obvious that a configuration for forming various first plastic hinge portions may be adopted to form two or more plastic hinge portions.

Although the preferred embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited to these specific embodiments, and may be appropriately changed within the scope described in the claims.

Claims

Pillars supporting the building;

A beam joined by a joint to the column in a direction crossing the column;

A first plastic hinge portion in which the cross-sectional moment performance of the beam is reduced in a direction away from the junction of the beam; And

A second plastic hinge portion in which the cross-sectional moment performance of the beam is reduced in a direction away from the first plastic hinge portion at the joint portion;

Steel structure having a seismic middle moment junction comprising a.
The method of claim 1,

Sectional moment performance of the second plastic hinge portion is smaller than the first plastic hinge portion, characterized in that the steel structure having a seismic intermediate moment joint portion.
The method of claim 2,

The cross-sectional moment performance of the second plastic hinge portion and the first plastic hinge portion is a steel structure having a seismic intermediate moment joint portion characterized in that the plastic deformation is generated at the same time by the load applied to the steel structure.
The method according to any one of claims 1 to 3,

Steel frame structure having a seismic intermediate moment joint portion, characterized in that the width of the flange of the first plastic hinge portion is formed smaller than the flange width of the beam of the joint portion.
The method of claim 4, wherein

Steel frame structure having a seismic intermediate moment joint portion characterized in that the flange width of the first plastic hinge portion is reduced in a curved shape.
The method of claim 4, wherein

Steel frame structure having a seismic middle moment joint portion characterized in that the flange width of the first plastic hinge portion is reduced in a straight shape.
The method of claim 4, wherein

Steel frame structure having a seismic intermediate moment joint portion, characterized in that the flange width of the second plastic hinge portion is smaller than the flange width of the joint portion.
The method according to any one of claims 1 to 3,

Steel frame structure having a seismic intermediate moment joint portion characterized in that the flange thickness of the second plastic hinge portion is formed thinner than the flange thickness of the first plastic hinge portion.
The method of claim 8,

A steel structure having an earthquake-resistant intermediate moment joint, characterized in that the flange of the second plastic hinge portion, which is thinner than the flange of the first plastic hinge portion, is joined to the side of the flange of the first plastic hinge portion.
The method of claim 8,

The bottom flange is integrally formed with the coupling part, the first plastic hinge part and the second plastic hinge part,

Steel structure having an earthquake-resistant intermediate moment joint portion characterized in that the upper flange is coupled over the upper surface of the coupling portion and the first plastic hinge portion of the bottom flange.
The method according to any one of claims 1 to 3,

The strength of the flange of the second plastic hinge portion is less than the strength of the flange of the first plastic hinge portion, the steel structure having an earthquake-resistant intermediate moment junction, characterized in that the same.