KR20090042121A - Concrete-filled steel pipe columns and manufacturing method thereof - Google Patents

Abstract

According to the present invention, since a steel plate serving as a building pillar and concrete formwork is bent into a "c" shape or a semicircle and then welded to two sides with each other, only two sides are welded, so that four steel plates are welded. Therefore, the amount of welding is reduced by half and the bending deformation due to welding is reduced, and the filling amount of concrete is increased as much as possible while reducing the thickness of the steel plate, supporting only the thickness of the steel plate, and the concrete plays only an auxiliary role. The present invention relates to a concrete-filled steel pipe column capable of increasing the spread of the CFT method, which is excellent in economy and construction, since it can reduce the use of expensive steel sheets while maximizing the compressive force of the concrete away from the conventional CFT method.

To this end, the present invention by bending the steel plate by half of the steel pipe pillar to form a steel pipe pillar by welding the bent both ends facing the two bent iron plate, the bent both ends and the bent center to be at least three stories high by floor A beam connecting diaphragm having a cross-shaped vertical wall having a plurality of guslet outlets for connecting the beams in all directions and integrally formed with a plurality of gussets connected to the beams through the gusset outlets is interposed between the bent iron plates. There is a feature that is welded in the built-in state.

Description

Concrete Filled Steel Tube and it's manufacturing method

The present invention by bending the iron plate acting as a building pillar in the "c" or semi-circular shape and then two to each other to produce a steel pipe column of rectangular or circular cross-section, the amount of welding is reduced by half than when welding four iron plates butt By reducing the thickness of steel sheet and increasing the amount of internal filling concrete as much as possible, it is economical to reduce the use of expensive steel sheet while maximizing the excellent compressive force of concrete, maximizing the concrete's excellent compressive force away from the conventional CFT method, which supports only the thickness of steel sheet and only serves as a secondary role. In view of the present invention, the present invention relates to a concrete-filled steel pipe column capable of increasing the spread of the CFT method and a method of manufacturing the same.

Concrete Filled Steel Tube (CFT) is a concrete filled steel tube column that is filled with concrete. It has excellent seismic performance and rigidity, and it has the advantages of reducing fireproof coating and excellent fire resistance. (Steel Frame), RC, and SRC, the fourth structure has recently been in the spotlight, and the building structure by this method is adopted in Japan, China, and Korea.

Since the filling of concrete is important, high flowable concrete is used, and the concrete needs to be filled without voids in the column. The basement is usually cast from the top with hoppers and concrete buckets, and the ground-floor column is casted back from the bottom of the column with pump pipes or from the top with a tram tube.

In the conventional CFT structure, four steel plates forming one side of a column are welded to each other to produce a steel pipe column having a rectangular cross section. In the process of welding four steel plates, the diaphragm for beam connection of the building was built to reinforce the connection between beams and columns.

However, since four places have to be welded to form a column, a large amount of welding results in heat deformation of the column.

In the CFT structure, the beams and columns transfer all the loads at the joints, so the CFT steel pipes can be locally broken by the force acting on the beams, or the joints can be broken prematurely by the stress concentration that causes local deformation of the steel pipes. For this reason, it is essential to make proper reinforcement to ensure that the joints of the columns and beams have sufficient rigidity and strength. The joint reinforcement of concrete filled steel pipe columns and beams can be divided into shear reinforcement and moment reinforcement.

Conventionally, a steel plate addition reinforcement method for increasing the thickness by applying an iron plate on the outer surface of a column for shear reinforcement and a stud bolt joint reinforcement method for joining a stud bolt to the inner surface of a concrete filled steel pipe column have been adopted. However, the method of reinforcing steel plate is less economical due to the demand of steel plate with considerable thickness, and the method of reinforcing the stud bolt joint reinforces the shear force of the beam to the inside of the concrete filled steel pipe because the reinforcement range of the stud bolt is limited to the inner side of the steel pipe. There was no problem.

In addition, the diaphragm method of inserting a beam connecting diaphragm to the joint part by moment reinforcement has been adopted. Conventional diaphragm method can be divided into the inner diaphragm method, the outer diaphragm method and the through-type diaphragm method according to the insertion position of the diaphragm. However, because the diaphragm must be installed in the middle of the pillar, there is a problem in that the middle portion needs to be partially cut.

Korean Registered Patent No. 660524 is shear reinforced with a vertical internal reinforcing plate that joins double-sided stud bolts into a column, and adopts a cross-shaped plate as an internal diaphragm to provide a concrete filled steel pipe column that can transfer stress without changing the shape of the joint. Reinforcing structures of beam joints have been disclosed.

However, since the diaphragm and the internal reinforcing plate should be installed in the middle of the column, one side of the column had to be welded to the three sides of the column in the open state, and there was a need to weld the diaphragm and the internal reinforcing plate. In addition, there is a problem in the material deformation and bending stress response of the iron plate by the welding heat by lateral welding the column to the axis. In addition, when the four poles are welded to each other by joining four iron plates to each other when manufacturing the column, there is a problem that the welding amount is increased, so that the contraction deformation of the column is caused, and the steel plate is thick, thereby reducing the economic efficiency.

Japanese Patent Laid-Open No. 1-290844 discloses a column-beam connection structure in which a cross-shaped diaphragm having concrete filling holes and holes for reinforcing steel bars is directly connected to upper and lower gussets of steel golbo beams. In the above, a structure in which a diaphragm in which a sleeve is inserted is welded to a steel pipe has been disclosed. In Japanese Patent Laid-Open No. 62-072841, a sleeve is embedded in an inner center of a steel pipe at a site where a column and a beam are joined, and a stiffener is inserted between the steel pipe and the sleeve. The structure has been disclosed, and Japanese Patent Laid-Open No. 6-294159 discloses a structure in which a tubular member is embedded in the inside of a steel pipe column surface or a concrete filled steel pipe column surface welded and bonded to a bogie sheet. 288001 discloses a structure in which vertical ribs and diaphragms are welded to the inside of concrete-filled steel pipe columns welded with bogie sheets. 5-346039 discloses a column-beam connection structure in which a vertical stiffener is attached to an inner surface of a steel pipe at a concrete-filled steel pipe column-SRC beam connection, and Japanese Patent Laid-Open No. 5-156710 discloses a square or circular steel pipe column-beam. A joint structure in which a vertical stiffener is attached to the inside of a joint has been disclosed. In Japanese Patent Laid-Open No. 6-306942, an outer diaphragm is welded between a bogie sheet and a steel pipe column, and reinforced with a vertical stiffener on the inner surface of the steel pipe at the site. One structure has been disclosed.

However, these are also methods of shear reinforcement or diaphragm welding with one side of the column open, thus making it inferior in fabrication and producing four columns by welding the steel plates separately, which increases the welding points, which causes shrinkage deformation of the steel plate. There was a downside.

The present invention has been developed in view of the conventional problems, the object of the present invention is to form a square or circular bending of the iron plate that acts as a building pillar and concrete form the "c" shape or semi-circle, and then weld the two sides to each other, square or round Since it is made of steel pipe columns of cross section, the welding amount is reduced by half and the bending deformation due to welding is reduced, compared to when manufacturing four rectangular steel pipe columns by welding four flat steel plates, and the filling amount of concrete is maximized while reducing the thickness of the steel plate. By increasing the thickness of steel plates and reducing the use of expensive steel sheets while maximizing the compressive force of concrete, it is possible to increase the spread of CFT methods with excellent economic feasibility. To provide concrete filled steel pipe columns.

Another object of the present invention is to produce a steel pipe pillar with a diaphragm having cross-vertical vertical walls intersected between the bent steel plates, but at the ends of these vertical walls, a gusset and a reinforcing piece projecting out of the steel pipe pillar. By forming and welding with the outer circumferential surface of the bent steel sheet, the diaphragm does not need to be welded inside the column, making it simple to fabricate, shear reinforced in the gusset connected to the beam, and moment reinforcement in the reinforcing piece contacting the upper flange of the beam. In particular, when concrete is poured into the steel pipe column, the vertical walls of the diaphragm are buried in the concrete, so when the vertical wall connected to the beam through one reinforcement receives the tensile moment due to deflection of the beam, the other vertical walls perpendicular to the concrete are Buried support ensures more moment reinforcement for improved reliability To provide concrete filled steel pipe columns.

Still another object of the present invention is to provide a concrete-filled steel pipe column which can increase the packing density of concrete without applying voids by applying vibration to reinforcing bars inserted into the column while pouring high-strength concrete from the top of the column.

Steel pipe pillars of an embodiment of the present invention by bending the iron plate in the "c" shape to form a bent iron plate formed with vertical bending surfaces on both sides of the horizontal plane and then weld the bending surfaces facing each other with two bent steel plates to form a steel pipe column of rectangular cross section As a result, the amount of welding is reduced by half compared to when the four steel plates are squared and the four welds are reduced, so that the bending deformation due to the heat of the welding is reduced, and at least three layers of heights are formed at opposite ends and horizontal surfaces of the bent plate. The beam connecting diaphragm having a cross-shaped vertical wall having a plurality of giant sheet outlets through which the beams can be connected in four directions is formed, and a plurality of giant sheets connected to the beams and four directions are integrally formed through the giant sheet outlets. Since welding is embedded between the steel plates, deflection in the vertical wall connected with the beam when the deflection occurs Soon as the other, so that the vertical wall perpendicular to the vertical wall support in the filled concrete on a steel pipe at the same time the moment of deflection is characterized in that the dual inhibition.

And the present invention can be used to cut the iron plate by using a large press or to produce the iron plate in the steel mill to produce a steel sheet corresponding to the half of the steel pipe column to cut as necessary length.

According to the present invention, a plurality of stud bolts are bent at a predetermined interval on the inner wall surface of the bent steel plate by welding a plurality of spacing bars on the bent surfaces facing each other after bending the steel plate in a "c" or semi-circular shape. By attaching the welding, the binding force with the internal filling concrete was enhanced, and when the two bent steel plates were welded to each other, the steel pipe columns of square or circular cross section were completed, so that the welding amount was reduced to half of the conventional steel pipe columns. Reduced shrinkage reduces productivity of straightening and improves productivity.

Before welding two bent steel plates, beam connecting diaphragm was made in the form of cross-shaped vertical wall and embedded at least three places, so that beams supporting the three-storey building floor slab can be connected. Because of the direct welding in the middle of the layer, the coupling of the beam connecting diaphragm and the pillar is more robust, preventing the beam shear and deflection moment.

In particular, since the beam connecting diaphragm has a cross-shaped vertical wall inside the steel pipe column, when these vertical walls are embedded in concrete, the other vertical wall perpendicular to this when the moment acts as the deflection of the beam on one vertical wall acts on the concrete. Moment of deflection can be suppressed, and high-strength concrete is poured from the top of the column, but when vibration is generated by reinforcing bars embedded into the column, the concrete is filled without voids, thereby increasing the density and improving the strength of the column.

1 is an exploded perspective view of a steel pipe pillar of one embodiment of the present invention, Figure 2 is a perspective view of a beam connection diaphragm for a steel pipe pillar of one embodiment of the present invention, Figure 3 is a front view of a steel pipe pillar of one embodiment of the present invention. The steel plate was bent in the shape of "c" corresponding to half of the square steel pipe to form a bending plate 11 having bending surfaces 13 which are both ends bent at both ends of the horizontal surface 12 which is the bending center. In order to maintain the flatness of (13), a plurality of spacing bar 20 is welded at equal intervals between the opposing surfaces. In addition, the bending iron plate 11 is welded to the plurality of stud bolts 60 to increase the binding force between the iron plate and the concrete when the concrete is filled in the steel pipe column.

The KS D 3864 cold-formed square steel pipe manufacturing method established in 1999 allows cold press forming up to 1000mm × 1000mm × 44mm for the steel sheet size, so that the required sheet thickness up to 44mm can be used according to the building height.

Since the bent steel plate 11 is made of a pair of steel pipe pillars 10 in a pair of two, forming a gusset outlet 14 for beam connecting only one of the bent surfaces 13 facing each other. The beam-shaped beam is connected to the gusset 32 to be described later.

The gusset outlet 14 is a place where the beam connecting gusset 32 of the beam connecting diaphragm 30 is inserted and welded, and at least three gusset outlets 14 are formed to form a single column 3 It is configured to form the height of the layer, and the gutter sheet outlet 14 to be inserted and welded to the horizontal surface 12 is formed. In addition, both ends of each gusset outlet 14 are also formed with a reinforcing piece outlet 15 to which the reinforcing piece 33 for welding the upper flange of the beam is fitted.

When the two bent steel plates 11 are opposed to each other to weld opposite ends of the bent surfaces 13, a steel pipe column 10 having a rectangular cross section is formed. When welding the bent surface 13 of the steel pipe column 10, the back bar 51 is welded to the inside to form a weld 50 to the outside of the iron plate.

In addition, the horizontal maintenance bar 21 passes through the horizontal maintenance bar 21 on each of the bent steel plates 11, and then the horizontal maintenance bar outlet 16 for welding the outer circumferential surface of the bending iron plate 11 and the horizontal maintenance bar 21. ). The horizontal retaining bars 21 are intended to prevent the horizontal surfaces 12 facing each other from expanding and deforming due to the placing pressure of the concrete filled in the pillars and to increase the binding force of the concrete, thereby increasing the load bearing capacity and ductility, and maintaining these horizontal levels. The bars 21 are fitted to the horizontal surfaces 12 alternately with each other in a direction orthogonal to the spacing bar 20, and both ends are welded to the horizontal surfaces 12 through the reinforcing rings 22.

The beam connecting diaphragm 30 is sandwiched between the bent iron plates 11 before welding them together. The beam connecting diaphragm 30 is in the form of an iron plate having a vertical wall 31 intersected in a cross shape, and is inserted into the giant seat outlet 14 of the bent iron plate 11 and protrudes outward from the pillar 32. Is provided at the ends of the vertical walls 31. These gussets 32 are connected to the I beam-shaped building beams, and a plurality of bolt holes are formed.

At the ends of the vertical walls 31 are provided with reinforcing pieces 33 orthogonal to the upper and lower sides of the gussets 32 to be welded to the upper flange or upper and lower flanges of the building beam. The plurality of stud bolts 60 are welded to the surface of the vertical walls 31 to increase the binding force with the concrete, thereby effectively using the compressive force of the concrete.

The vertical walls 31 are a portion that receives the shear force due to deflection when the building beam and the gusset 32 are connected, and the reinforcing pieces 33 are portions that receive a moment due to tension. Since the beam connecting diaphragm 30 of one embodiment of the present invention is provided with a cross-shaped vertical wall 31, when the vertical walls 31 are embedded in concrete, the binding force with the concrete is increased through the stud bolt 60, so that the shear force and Since the resistance to the moment is increased, in particular, the other vertical wall perpendicular to the vertical wall 31, which is subjected to the force, is supported by the concrete, thereby increasing the shear resistance and the moment resistance due to the deflection of the beam.

Steel pipe pillar 10 is welded to the reinforcing diaphragm 40 having a concrete inlet 41 in the upper, lower ends. The reinforcing diaphragm 40 is for reinforcing for contributing to the joining precision of the opposing surfaces when welding the column and the pillar, the reinforcing diaphragm 40 has a plurality of reinforcing bars 42 entering the inside of the steel pipe column 10 It is provided. These reinforcing bar 42 is a part that generates vibration when the concrete is put into the concrete uniformly spreads inside the steel pipe column 10 serves to prevent the generation of voids. The shock absorbing material 43 is embedded between the reinforcing bar 42 and the reinforcing diaphragm 40 so that the vibration applied to the reinforcing bar 42 is not transmitted to the steel pipe column 10. In addition, the reinforcing bar 42 is formed to be longer than the steel pipe column 10 to enter the other pillars when welding the pillars and pillars so that the reinforcing bars and reinforcing bars reinforce the connection welds of the pillars and pillars.

The pillar of one embodiment of the present invention manufactured as described above is connected to at least three beams 70 to one steel pipe column 10 to form a three-story building. The beam 70 is fastened with a bolt to the seat 32 formed on the beam connection diaphragm 30 of the steel pipe pillar 10 to form a steel frame.

As shown in FIG. 7, one side of the beam 70 is bolted to the gusset 32 of the beam connecting diaphragm 30 formed on the steel pipe column 10, and sheared and reinforced, and the upper flange of the beam 70 is a gusset. (32) the steel pipe column 10 and the beam 70 is connected by welding the reinforcement piece 33 of the upper part by reinforcing the moment, and when the steel frame of the building is completed, the concrete inlet 41 of the upper part of the steel pipe column 10 is completed. Inject high strength concrete (80). At this time, by tapping the upper end of the reinforcing bar 42 with a vibration generator so that the concrete spreads well, when the vibration is transmitted to the reinforcing bar 42, the injected concrete spreads well without sticking to one side. When the concrete 80 is filled in the inside of the steel pipe column 10 should be separated from the column and the column welded by about 1000mm or more so as not to be affected by the welding heat with the other steel pipe column (10). And when the concrete is injected into the demi-tube method, the camera is installed at the end of the concrete injection hose and installed while checking the filling state of the concrete.

9 to 10 is a cross-sectional view showing a connection state of the pillar and the beam of another embodiment of the present invention, the beam connecting diaphragm 30 is made of vertical walls of the well sperm form and the geo seats 32 are also Two formed on each side. In this way, not only the beam of the I beam in cross section, but also the TSC beam 70a having a U cross section can be connected. And the bottom surface of the gusset 32 forms a reinforcing rib 71 to prevent sagging of the TSC beam 70a.

11 to 12 is a front view and a plan view of a steel pipe column according to another embodiment of the present invention, having the same configuration as the embodiment of the present invention. Only a plurality of steel pipe pillars (10-1 to 10-7) is connected to each other to reduce the cross-sectional area from the lowest column (10-1) to the uppermost column (10-7) so that the tapered inclination By reducing the use of iron plate.

Since the load from the column decreases toward the upper part of the building, the amount of iron used is reduced by making different cross-sectional areas of the lowermost column and the lowermost column.

13 to 14 is a perspective view and a cross-sectional view of a steel pipe pillar of another embodiment of the present invention, by bending the iron plate to produce a bent iron plate (11a) having three sides of the square pillar and the other side of the flat iron plate (not bent) Except for using 12a) it has the same configuration as the embodiment of the present invention.

The bent plate 11a is formed with a gutter sheet outlet 14 and a reinforcing piece outlet 15 in the horizontal surface 12 and the bent surfaces 13, and the gutter sheet outlet 14 is also formed in the flat plate 12a. The reinforcing piece outlet 15 is formed. A plurality of gap maintaining bars 20 are installed between the bending surfaces 13 of the bent steel plate 11a to maintain the flatness of the welded part, and then the beam connecting diaphragm 30 is embedded in the bent steel plate 11a. The flat iron plate 12a is welded to produce a steel pipe column 10a. Then, the reinforcing diaphragm 40 having the reinforcing bars 42 is welded to both ends of the steel pipe pillar 10a to increase vertical accuracy when the pillar and the pillar are connected.

Since the beam connecting diaphragm 30 has a cross-shaped vertical wall 31, the beam connecting diaphragm 30 may not enter between them unless the thick bent surfaces 13 are opened. In this case, the vertical walls are bisected into a "b" shape and welded inside the bent plate 11a to make a cross-shaped vertical wall, or the vertical walls are separated and welded with a separate clamp that cross-connects them in the center to form a cross. After welding the corresponding sides of the flat iron plate (12a) and the bent iron plate (11a) it can be produced a steel pipe column with a diaphragm embedded.

15 to 16 is a perspective view and a flat shaving of a steel pipe pillar of another embodiment of the present invention, except that the steel pipe pillar (10b) is made in a circular cross section has the same configuration as the embodiment of the present invention.

The iron plate is bent in a semi-circular shape to produce a semi-circular bending iron plate 11b, and to form a gutter seat outlet 14 and a reinforcing piece outlet 15 for fastening the beam connecting diaphragm 30 at the center and the end of the bent surface. In addition, a plurality of gap retaining bars 20 are welded to the bent surface ends of the semi-circular bent iron plate 11b to maintain flatness of the portion to be welded. Thereafter, the two semi-circular bending iron plates 11b are welded to each other but welded with a beam connection diaphragm 30 embedded therein to produce a steel pipe column 10b, and reinforcing diaphragms 40 having reinforcing bars 42 at both ends thereof. Weld a steel pipe column with a circular cross section.

Steel pipe column according to another embodiment of the present invention has a circular cross section, so the indoor occupancy is lower than that of the square column, which is advantageous in terms of space utilization and is structurally stable.

1 is an exploded perspective view of a steel pipe pillar of one embodiment of the present invention

Figure 2 is a perspective view of the beam connecting diaphragm for steel pipe pillars of one embodiment of the present invention

3 is a front view of the steel pipe pillar of one embodiment of the present invention

4 is a cross-sectional view taken along the line A-A of FIG.

5 is a cross-sectional view taken along the line B-B of FIG.

Figure 6 is a front view showing a connection state of the steel pipe column and beam of an embodiment of the present invention

7 is a cross-sectional view of the concrete poured inside the steel pipe pillar of an embodiment of the present invention

8 is a block diagram showing a steel pipe pillar manufacturing process of an embodiment of the present invention

9 is a front view showing a connection state of the steel pipe column and beam of another embodiment of the present invention

10 is a cross-sectional view taken along the line C-C of FIG.

11 to 12 is a front view and a plan view of a steel pipe pillar of another embodiment of the present invention

13 to 14 is a perspective view and a cross-sectional view of a steel pipe pillar of another embodiment of the present invention

15 to 16 is a perspective view and a cross-sectional view of a steel pipe pillar of another embodiment of the present invention

<Code Description of Main Parts of Drawing>

10: steel pipe pillar 11: bending sheet iron

12: horizontal plane 13: bending surface

14: gutter seat outlet 15: reinforcement piece outlet

20: spacing bar 21: horizontal bar

30: beam connection diaphragm 31: vertical wall

32: gusset 40: reinforcing diaphragm

41: concrete inlet 42: rebar

50: weld 60: stud bolt

Claims (9)

Bending the steel plate by half of the steel pipe column, and then welding the bent ends of the two opposite steel plates to form a steel pipe column, The bent both ends and the bent center is formed with a plurality of gersheet outlets that can connect the beams in each direction to be at least three stories high, And a beam connecting diaphragm having a cross-shaped vertical wall integrally formed with a plurality of giant seats connected to the beams through the giant seat outlets and welded in a state embedded between the bent steel plates. The method of claim 1, Bending both ends of the bent iron sheet is formed with a plurality of gap maintaining bar to prevent expansion deformation during the filling of concrete while increasing the flatness and welding precision therebetween, Concrete-filled steel pipe column, characterized in that the two bent steel plate is welded on the inner wall surface of the bent iron plate is formed with a plurality of stud bolts to increase the binding force with the concrete. The method of claim 2, Vertical walls of the beam connecting diaphragm are formed with reinforcing pieces welded to the upper and lower flange portions of the beams to the upper and lower sides of the corresponding seat sheets. Concrete filled steel pipe column, characterized in that the reinforcing piece outlet port is formed in the gusset outlets of the steel pipe pillar to guide the reinforcement piece is inserted to protrude out of the column. The method of claim 2, In the center of the bent iron plate constituting the steel pipe column is formed a horizontal retaining bar outlet through the gap retaining bars and penetrating them, Concrete-filled steel pipe pillars are inserted into the horizontal holding bar outlet and welded to the outer circumferential surface of the center of the bending iron plate and provided with a horizontal holding bar to prevent the expansion of the center of the bending iron plate when the concrete is filled. The method of claim 2, Reinforcing diaphragm having a concrete inlet is provided in the upper, lower ends of the steel pipe pillars concrete filled steel pipe pillars, characterized in that to increase the vertical accuracy when connecting a plurality of steel pipe pillars. The method of claim 5, wherein The reinforcing diaphragm of the upper side is provided with a plurality of reinforcing bars embedded in the concrete is introduced into the steel pipe pillar, A concrete filled steel pipe pillar, characterized in that the buffer is provided between the reinforcing bar and the reinforcing diaphragm to prevent the shaking of the steel pipe column when the reinforcement is hit by a vibration generator to prevent the tendency and aggregation of concrete. The method of claim 2, The steel pipe pillar has a cross section of one of the square or round, the bent steel sheet is a concrete filled steel pipe pillar, characterized in that bent by a press. The method of claim 2, The steel pipe pillars are inclined in a tapered shape when joined to each other, so that the cross-sectional area is reduced from the lowest pillar to the upper pillar. Preparing a bent iron plate by bending an iron plate to correspond to half of a steel pipe column; Forming a gutter sheet outlet for connecting beams to each floor such that the beams are at least three stories high at the bent ends and the bent center of the bent steel sheet; Preparing a beam connecting diaphragm having a cross-shaped vertical wall integrally formed with a gusset connected to the beam by being inserted into the guslet outlet; Butt welded both ends of the bent iron plate and the bent both ends of the built-in beam connection diaphragm between the concrete filling steel pipe pillar characterized in that the steel sheet protruding its gusset through the gut sheet outlet Manufacturing method.

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