JP3126093B2 - Beam-column joints of steel structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam-column joint of a steel structure, and more particularly to a ductile joint.
y) is high and is related to the beam-to-column-connection (also called beam-to-column-connection) in steel structures with excellent earthquake resistance.

[0002]

2. Description of the Related Art Steel structures are widely used even in high-rise buildings in the Republic of China (Taiwan, Japan, etc.), but because the steel structures themselves have the properties of prefabricated construction methods, they have It was necessary to assemble the beam-column joint at the site by welding or bolting. And
The strength and ductility of such beam-to-column joints have been one of the most important issues in steel structure research. According to past research in the Republic of China (Taiwan Province), We knew that the strength of the joints had reached a certain standard for the time being, but the ductility was greatly affected by the detailed structure and construction method, so it was brittle. Occasionally, I heard the phenomenon of brittle fracture.

[0003] First, the ductility of a beam-column joint will be described with reference to FIG. 5. The ductility of a beam-column joint is determined by the plastic rotational angle.
le) In the example of a cantilever (cantilever beam) shown in FIG. 5 which can be expressed by θ _P , the cantilever receives plastic acting at one end thereof due to the acting force of the load P.
Let δ be the total deflection of this free end, and let δ _{P be} the plastic deflection after subtracting the elastic deflection.
If the beam length is L, the plastic rotation angle can be defined as in the following formula 1 (in formula 1, θ _P = δ _P / L).
As can be seen from this definition, if the plastic rotation angle θ _P is large, the ductility of the beam-column joint is excellent.

Θ _P = Min [Abs (+ θ _P , −θ _P )] (Equation 1) However, in the past, it was repeated about the beam-to-column connection of a large steel structure of 37 high-rise buildings in the Republic of China (Taiwan Province). When a load was applied, the average value of the plastic rotation angle θ _P of the beam-column joint was only 0.92%, which was far from the general standard of at least 1.5% or more. In other words, in the Republic of China (Taiwan Province), although the actual strength of many high-rise steel structures has achieved design standards, the lack of ductility alone has become a universal phenomenon. It was the current situation.

According to the current state of the art, in the prior art, the column-beam joining method of the steel frame structure uses a box-column (also referred to as a box-shaped column) shown in FIG.
It was divided into a type in which a shaped beam (H-beam) was joined and a type in which an H-shaped beam was joined to an H-column shown in FIG. First, in the type shown in FIG. 6, an H-shaped beam 2 including a joint portion is
The joints were formed at portions 1 and 12, where 21 was a bolt and 22 was a welding line (also called a weld bead). In addition, the type shown in FIG.
The mold beam 2 was joined at the partition steel plates 11 'and 12'. In order to solve the problem that the ductility of the beam-column joint is insufficient, conventionally, it was usual to additionally weld the cover plate 23 to the joint.
Steel beams and flange plates used for high-rise buildings usually have a thickness of 40 to 50 mm or more, so if additional cover plates are welded, the amount of on-site welding will increase significantly. Not only that,
Because of the welding of thick steel plates, its quality control is difficult, and it is not satisfactory as a means to solve the problem of insufficient ductility in current steel high-rise buildings. However, it also increased the construction costs to some extent.

[0006]

The problems to be solved by the present invention are as follows: the ductility of the steel frame structure is poor in ductility due to insufficient ductility and lacks in earthquake resistance. However, construction costs increase.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a beam-to-column joint of a steel structure formed at one end of an H-shaped beam and used to join the H-shaped beam to a column. And simultaneously forming a pair of notches facing both sides of each flange plate along the longitudinal direction of the H-shaped beam in the H-shaped beam having a pair of flange plates at opposed portions of the web plate. The main feature is that it is. Improve the ductility of beam-to-column joints by simply adding small notches to the flange plate at the beam-to-column joints of steel structures, or without the need for additional on-site construction. Achieved its goal of improving its earthquake resistance.

[0008]

Next, the operation of the present invention will be described based on the technical concept of the present invention. FIG. 8 explains the technical idea of the present invention. In FIG. 8, reference numerals 31, 32, and 33 denote steel plates made of the same three materials. And the steel plate 31 as a standard tension sample. The intermediate portions of the steel plates 31, 32, and 33 after receiving the acting force reach the yield point at the same time, but when the steel plate 32 is loaded on both ends, the stress / strain concentrates on the portion where the cross-section becomes minimum. Therefore, brittle fracture occurs. The steel plate 33 is similar in shape to the steel plate 31, but has a longer yield area than the steel plate 31, and thus has an overall better energy dissipation capability than the steel plate 31.

Referring to FIGS. 9 to 12, a rigid frame (mome) is shown.
When an nt resisiting frame (Ramen = German: also called Rahmen) is vibrated by an earthquake, the moment is mainly determined by the upper and lower two flange plates 41 and 42 (due to the characteristics of the cantilever type H-shaped beam 4 itself). H is supported by forming a couple by the acting force of H (see FIG. 10).
As the moment gradually decreases along the longitudinal direction of the mold beam 4 (see FIG. 11), its flange plate 4
As shown in FIG. 13, the stresses on the steel plates 1 and 42 also gradually decrease, so that the steel plates 5 whose widths are widened can be replaced with steel plates 5 which receive an equal force at one end, as shown in FIG. The structure type of the steel plate 5 shown in FIG. 13 is equivalent to the steel plate 32 of FIG. 8, and a stress concentration phenomenon occurs. And the ductility was extremely low, and as a result, brittle fracture occurred.

Therefore, as can be seen from the above description, if the upper and lower two flange plates of the H-shaped beam are connected to the magnitude of the moment (or the required moment,
If notching is performed according to t), it is possible to realize a uniform yield of stress.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below with reference to the drawings. Referring to FIG. 1, a description will be given of a case in which a beam-column joint of a steel structure according to the present invention is joined to an H-shaped beam to a box column. 6 is a box column, 7 is an H-shaped beam, Reference numeral 8 denotes a joint, and the joint 8 is an H-beam 7
And welding means (91 represents a welding line)
And the bolt 94 to the box column 6. The joining portion 8 includes a pair of upper and lower flange plates 8.
1 and 82 and a web plate 83, and the flange plates 81 and 82 are formed above and below the web plate 83, respectively. Then, in order to realize a uniform yield of stress, a pair of corresponding notches 80, 80, 80, 80, 80, 80, 80, 8
0, but undesired effects of the welding operation (eg heat effect zone, residual stress,
In order to avoid welding defects, etc.,
Cuts the surface of the box column 6 from a position slightly away from the surface of the box column 6 and guarantees the formation of a plastic hinge, and avoids affecting the rigidity of the notch 80 due to excessive notches. The notch width is 90% to 95% of the required moment (that is, when the flange plates 81 and 82 have the flange width of the notch portion,
The notch is set so as to be 90% to 95% of the required moment, and the range of the notch 80 extends from the surface of the box column 6 along the longitudinal direction of the H-shaped beam 7 to the beam depth. 2 times or less (2 when beam back is D)
D or less) and polished so as to smooth the unevenness generated on the cutout surface.

FIG. 2 shows a case where a beam-column joint of a steel structure according to the present invention is joined with an H-shaped beam to an H-shaped column, and 6 'denotes an H-shaped column.
The other parts are completely the same as the box column and the H-beam joint shown in FIG. 1 and will not be described again. 3 and 4, the column-beam joint of the steel structure according to the present invention is different from the conventional one-point yielding (see FIG. 3) in the area type yielding (see FIG. 3) when the steel structure receives an acting force. 4
) To increase the ductility of dissipating energy. As a result of the measurement test, the average plastic rotation angle is five times that of the conventional structure, and the construction at the factory or site is easy. It was proved that the quality control became easy and that it was excellent in earthquake resistance.

Although the preferred embodiment according to the present invention has been disclosed above, it is not intended to limit the present invention, and those skilled in the art can modify or change the technical concept and technical scope of the present invention. Naturally, the scope of protection of the technical concept of the present invention is based on what is described in the claims.

[0014]

According to the present invention, the ductility of a beam-to-column joint in a steel structure can be improved to about 5 times on average by the above-described structure, and it can be provided with excellent seismic resistance. Because it is a simple construction content of forming
Quality control is easy, and a significant increase in construction cost can be effectively suppressed in any construction at a factory or a site.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a case where an H-shaped beam is joined to a box column in a beam-column joint of a steel structure according to the present invention.

FIG. 2 is a perspective view showing a case where an H-shaped beam is joined to an H-shaped column in a beam-column joint of a steel structure according to the present invention.

FIG. 3 is an explanatory diagram for explaining a one-point yielding caused by a cantilever at a beam-column joint according to the related art.

FIG. 4 is an explanatory view illustrating an area-type yielding generated by a cantilever at a beam-column joint according to the present invention.

FIG. 5 is an explanatory view showing a state where a load is applied to a cantilever in general.

FIG. 6 is a perspective view showing a state in which a beam-column joint of a steel structure employing conventional cover plate additional welding has an H-shaped beam joined to a box column.

FIG. 7 is a perspective view showing a state in which an H-beam is joined to an H-column at a column-beam joint of a steel structure employing conventional cover plate additional welding.

FIG. 8 is an explanatory diagram showing a yield area generated by a load for three steel plate samples.

FIG. 9 is an explanatory diagram showing a load state of a cantilever employing an H-shaped beam.

FIG. 10 is a cross-sectional view of the H-beam shown in FIG.

FIG. 11 is an explanatory diagram for explaining the moment of the H-shaped beam shown in FIG. 9;

FIG. 12 is an explanatory diagram illustrating vertical stress in the flange plate of the H-shaped beam shown in FIG.

13 is an explanatory view illustrating a steel plate structure having an equivalent structure to the flange plate of the H-shaped beam illustrated in FIG. 9;

[Explanation of symbols]

 6 Box column 6 'H-shaped column 7 H-shaped beam 8 Joint 80 Notch 81 Flange plate 82 Flange plate 83 Web plate 91 Welding line 94 Bolt 1 Box column 1' H-shaped column 2 H-shaped beam 11 Partition steel plate 12 Partition steel plate 11 'Partition steel plate 12' Partition steel plate 21 Bolt 22 Welding line 23 Cover plate 31 Steel plate 32 Steel plate 33 Steel plate 41 Flange plate 42 Flange plate 5 Steel plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E04B 1/24

Claims (2)

(57) [Claims] An H-shaped beam is formed at one end of the H-shaped beam and used to join the H-shaped beam to a column. The web plate has two ends. A pair of flange plates, each of the pair of flange plates having a pair of notches on opposite sides thereof, wherein the notches provide a uniform yield of stress for the H-beam.
As There is realized, be between flange width between notches of the pair are 95% to 90% of the moment required amount Hitoshi
A beam-column joint of a steel structure having a structure other than one. 2. The notch according to claim 1, wherein said notch is within a range of extending a beam back from said column surface to a double length on a flange plate along a longitudinal direction of said H-shaped beam. The beam-column joint of a steel structure according to claim 1.