JPH063048B2 - Method of constructing filled steel tube concrete structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for constructing (manufacturing) a filled-type steel pipe concrete structure used as a pillar or an underground pile of a large building.

Conventional technology Concrete is filled in the hollow part of a steel pipe to bear a long-term axial force (vertical load) on the concrete and the filled concrete is constrained by the steel pipe, and bending force (horizontal force) and axial force at the time of earthquake are applied to the steel pipe. Filled steel tube concrete structures as composite structures to be loaded belong to various publicly known (see, for example, those described in JP-A-62-153438, JP-A-62-160337, JP-A-62-160338). ).

A large steel tube concrete structure is characterized by its extremely high bending deformation capacity, and in particular, its toughness when subjected to alternating positive and negative repeated bending. And this characteristic is remarkable in the filling type. It is thought that this is due to the synergistic effect that the local buckling of the steel pipe is constrained by the concrete as a result of filling the inside of the closed cross section of the steel pipe with the concrete, and the concrete is constrained by the steel pipe.

Conventionally, the basic method of constructing a filled-type steel pipe concrete structure has, of course, been to place the filled concrete by using a steel pipe as a mold substitute. However, according to this method, when the axial compressive strain of concrete increases due to creep or shrinkage after placing concrete, the steel pipe will bear the axial force that the concrete should originally bear. In this way, when a bending force acts on this structure in a state where the steel pipe bears the axial force, the yield strength naturally lowers as compared with the case where the steel pipe does not bear the axial force. On the contrary, since the filling concrete in the steel pipe does not bear the axial force that the steel pipe bears,
It is uneconomical because it does not fully exert its ability to work poorly and is resistant to compression.

Therefore, the improved construction method, as illustrated in FIG. 6, separates the upper and lower steel pipes 1 from each other to provide a gap 3, and the gap 3 completely absorbs axial compressive strain and the like of the filled concrete 4, Therefore, the filled concrete 4 is allowed to bear all the axial forces, and the steel pipes 1 and 2 simply restrain the filled concrete 4 to bear only the bending force.

Alternatively, as in the invention described in Japanese Patent Laid-Open No. 62-160336, a method of cutting a predetermined location of one steel pipe into a ring shape and making it into a gap for absorbing axial compressive strain of the filled concrete, or a vertical method A method of forming a gap by interposing a spacer between the steel pipes is also known.

Problems to be Solved by the Invention (I) According to the construction method in which the upper and lower steel pipes 1 and 2 are separated to form the gap 3 as illustrated in FIG. 6, an axial force is applied to the steel pipes 1 and 2. On the other hand, when the horizontal bending force such as the seismic force acts on the frame and the tensile force acts on the steel pipe concrete structure, the steel pipes 1 and 2 are completely useless and the filled concrete 4 bears the tensile force. It will be unreasonable to be forced. In addition, there is a big problem that the separation point 3 of the steel pipe becomes a break point in the transmission of the bending stress from the steel pipes 1 and 2 to the filled concrete 4.

(II) In this respect, in the case of the invention described in Japanese Patent Laid-Open No. 62-160336, the steel pipes separated into the upper and lower parts are finally joined by welding after the filled concrete is in a state of bearing the axial force. However, since they are joined by a bolted structure of a flange joint, some improvement is seen in the sense that the treatment of tensile force and the like is perfect.

However, regarding welding and joining the upper and lower steel pipes, because the filling concrete is clogged inside the steel pipes, if welding is performed without any measures, the welding heat will seriously damage and deteriorate the filling concrete, and later. There is a problem of leaving a weak point of resistance in the use of.

On the other hand, in the connection by the flange joint, the flange largely protrudes on the outer peripheral surface of the steel pipe concrete structure, which is a hindrance, and there is a problem that the aesthetic appearance is greatly impaired.

Means for Solving Problems As a means for solving the problems of the above-mentioned conventional techniques, a method for constructing a filled steel pipe concrete structure according to the present invention is carried out in a suitable manner as shown in FIGS. 1 to 5 of the drawings. As shown in the example, in a method of constructing a filled-type steel pipe concrete structure by filling concrete in the hollow portion of two or more steel pipes connected in series, a) two steel pipes 1 and 2 are formed by a form material 5 Through which the axial compressive strain or the like that occurs in the filled concrete 4 later is allowed, and a gap S having a size suitable for welding is opened to make a series of butt connections, and a void is formed in the inner periphery of the form material 5. Installing the material 6, and b) filling concrete 4 into the hollow portions of the steel pipes 1 and 2,
The step of removing the form material 5 and the void material 6 after the filled concrete 4 has hardened, and c) the butt joints of the steel pipes 1 and 2 are joined by welding after the construction of the upper layer is completed, and the inside thereof The step of filling the void material traces 7 with the grout 8 was performed.

In addition, as one embodiment, the form material 5 is a pair of split mold members 50 and 51 detachably fixed to the ends of the upper and lower steel pipes 1 and 2 with bolts 52 and the pair of split mold members 5.
Wedge 53 inserted inwardly between the facing surfaces of 0 and 51
And a wedge retainer 54 that holds the wedge 53 inward from the outside and is detachably fixed to the upper and lower split mold members 50 and 51 with bolts 55.

By interposing the form material 5, the upper and lower two steel pipes 1,
2 can be butt-connected in series with a gap s of suitable size.

Since the filling material 4 is hardened and axial compression strain or the like is generated in the concrete 4, the form material 5 is removed and the two steel pipes 1 and 2 are separated, so that the axial force is not transmitted to the steel pipes 1 and 2, and the compression is performed. The concrete 4, which is very strong, resists axial force.

When the steel pipes 1 and 2 are finally welded, the welding heat is directly applied to the concrete 4 due to the cavity 7 left after the void material 6 is removed.
Prevents damage and deterioration.

The steel pipes 1 and 2 that do not bear the axial force exhibit sufficiently large bending resistance and bending toughness against bending. Moreover, the steel pipes 1 and 2 that do not bear the axial force restrain the filled concrete 4 with a large force, and the filled concrete 4 is correspondingly restrained.
The compression yield strength and compression toughness of are improved.

Of course, the steel pipes 1 and 2 integrally joined by welding can sufficiently resist the tensile force caused by the horizontal force such as an earthquake, and the bending stress from the steel pipes 1 and 2 to the filled concrete 4 can be increased. It does not create any breaks in communication.

EXAMPLE Next, an example of the present invention shown in FIG.

First, FIG. 1 shows that two upper and lower steel pipes 1 and 2 to be connected in series are butt-connected via a form material 5, and a void material 6 is lined inside the form material 5 to form a steel pipe. It shows a stage where concrete 4 is placed in the hollow portions 1 and 2.

As shown in FIG. 2, the structural details of the mold material 5 include a pair of vertically symmetrical split mold members 50 and 51 that are detachably fixed to the ends of the upper and lower steel pipes 1 and 2 with bolts 52. It is a major member. A wedge 53 is inserted inwardly between the facing surfaces of the pair of split mold members 50, 51, so that the size of the gap s (see FIG. 3) between the upper and lower steel pipes 1 and 2 is the driving amount of the wedge 53. It can be fine-tuned by. Also,
The wedge 53 is also configured to facilitate the subsequent disassembly and removal of the formwork material 5. That is, when removing the form material 5, first, the wedge 53 is pulled out. Then, the steel pipe 1 for the upper and lower split mold members 50, 51
Since the restraint force due to its own weight can be released and the assembling configuration of the formwork material 5 is varied, the dismantling work such as loosening the bolt 52 can be easily performed thereafter.

The wedge 53 inserted between the facing surfaces of the pair of split mold members 50, 51 is constrained inward by a wedge retainer 54 abutting the outer end of the wedge 53 to prevent accidental accidental disengagement. There is. The wedge retainer 54 is composed of the upper and lower split mold members 50.
It is detachably fixed to bolts 51 and 51 with bolts 55. A soft seal material 56 is sandwiched between the opposing surfaces of the pair of split mold members 50 and 51 and inside the wedge 53. In this embodiment, the mold material 5 is configured to form a gap s between the upper and lower steel pipes 1 and 2 at about 50 mm.

The void material 6 is made of, for example, foamed polystyrene or rubber, and is installed on the inner peripheral portions of the upper and lower steel pipes 1 and 2 and the mold material 5 by an adhesive method or the like. The thickness of the void material 6 is 20 to 30 mm, and the height in the vertical direction is about 200 mm.

Next, FIG. 3 shows that after the poured filled concrete 4 has hardened, the form material 5 is removed to separate the upper and lower steel pipes 1 and 2 by the gap s, and the void material 6 is also removed to leave the trace. The stage which produced the cavity 7 is shown. At this stage, the upper structure of the building is built. Due to the erection of the upper layer, a long-term axial compressive force is applied to this steel pipe concrete structure, but as described above, the axial force is not transmitted to the steel pipes 1 and 2 separated by the gap s. Filled concrete 4 bears the long-term axial force. The strain due to the creep of the filled concrete 4 due to the axial force and the axial compressive strain are completely absorbed by the gap s.

FIG. 4 shows a stage in which the abutting portions of the two upper and lower steel pipes 1 and 2 are welded to each other after the erection of the upper layer is completed, in other words, after the creep and the axial compressive strain are completely generated. . In the figure, 9 is a welding point.

At the time of this welding, the cooling materials 10 and 10 are attached to the outer circumferences of the upper and lower steel pipes 1 and 2 and above and below the welding spot 9. Then, the heat transmitted to the inside of the welding heat is protected by the cavity 7 after the void material 6 is removed, and the steel pipes 1, 2
The heat transmitted in the vertical direction through the heat is blocked at the position of the coolant 10. Therefore, it is possible to prevent the filled concrete 4 from being damaged by the damage of the welding heat and the strength performance being deteriorated.

FIG. 5 shows the cavity 7 after the void material 6 is removed after the welding.
The figure shows a stage where the filling of the steel grout 8 is completed and the filling type steel tube concrete structure is completed.

The filling type steel pipe concrete structure constructed in this way is
Since the filled concrete 4 that resists the long-term axial force bears and resists all, and the bending force bears and resists the steel pipes 1 and 2 that resists bending, constructing a composite structure with ideal stress sharing become. In particular, since the steel pipes 1 and 2 do not bear any axial force for a long period of time, they exhibit greater bending resistance and bending toughness against bending. Moreover, since the steel pipes 1 and 2 are finally integrally joined by welding, they sufficiently resist the bending force and the tensile force at the time of earthquake.
And, since the steel pipes 1 and 2 which do not bear the axial force for a long period of time can naturally restrain the filled concrete 4 with a larger force, the compressive strength and the compression toughness of the filled concrete 4 are improved accordingly, and eventually the filled concrete is filled. The strength and deformation capacity of the structure, the seismic resistance, etc. are greatly increased.

Advantageous Effects of the Present Invention As described above in detail in connection with the embodiments, according to the method for constructing a filled type steel pipe concrete structure according to the present invention, the steel pipe 1, without damaging the filled concrete 4,
A filled steel tube concrete structure in which two parts are welded to each other is obtained. According to this structure, the filled concrete 4 bears all long-term axial force, and the steel pipes 1 and 2 bear only bending force and axial force during an earthquake. As a result, it is possible to significantly increase the yield strength and deformation capacity of the steel pipe concrete structure, and enhance the safety of the pillar or underground pile of the building.

Moreover, the steel pipes 1 and 2 are integrally welded together to form a structure that sufficiently resists tensile force, and at the same time, no obstacles are projected on the outer surface of the steel pipe, resulting in a beautiful design. You can build things that do not spoil. Further, it is possible to construct a steel pipe concrete structure that is not damaged or damaged by heat during welding.

[Brief description of drawings]

FIG. 1 is a sectional view showing a state of a first stage of the construction method of the present invention, FIG. 2 is an enlarged detailed view of a II portion in FIG. 1, and FIG.
FIG. 5 is a second, third, and third construction method of the present invention following FIG.
FIG. 6 is a sectional view showing a state of four stages, and FIG. 6 is a sectional view showing a conventional method.

Claims (2)

[Claims] 1. A method for constructing a filled-type steel pipe concrete structure by filling concrete into the hollow portions of two or more steel pipes connected in series, wherein a) two steel pipes (1) and (2) are formwork. Through the material (5), axial compressive strain or the like that occurs in the filled concrete later is allowed, and a gap (s) of an appropriate size is formed in the welded joint to make a butt connection in series, and this form material ( 5) a step of installing a void material (6) on the inner periphery of b), b) concrete (4) in the hollow portion of the steel pipe (1) (2)
And removing the form material (5) and the void material 6 after the filled concrete (4) has hardened, and c) after the upper layer has been erected, the steel pipe (1) (2) Weld the butt joints and leave traces of void material inside (7)
And a step of filling with grout (8), and a method for constructing a filled-type steel tube concrete structure. 2. A formwork material (5) is composed of upper and lower steel pipes (1) (2).
Of the pair of split mold members (50) and (51) detachably fixed to the ends of the pair with bolts (52), and the pair of split mold members (5).
0) A wedge (53) inserted inwardly between the facing surfaces of (51) and the wedge (53) is restrained inward from the outside, and is divided into upper and lower split mold members (50) (51). Wedge retainer (54) detachably fixed with bolts (55)
The method for constructing a filled-type steel pipe concrete structure according to claim 1, characterized in that