JP2003138583A - Underground column structure of structure and construction method for underground column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground column structure of a structure and a construction method for an underground column capable of greatly reducing complicated work when compared with a conventional method to provide excellent construction property and improving cross sectional performance and connection rigidity and horizontal resistance for a foundation of a pile head part. SOLUTION: The underground column 20 of the structure is constituted by a concrete filled steel pipe column (CFT) or a reinforced concrete filled steel pipe column (RCFT) joined integrally with an upper end part of a steel pipe pile 21.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a structure of an underground pillar in a structure having an underground portion and a method of constructing the underground pillar.

[0002]

2. Description of the Related Art Up to now, a reverse construction method has been known as a method for constructing an underground portion of a large structure in particularly soft ground. As shown in FIG. 4, this reverse driving method first drives the outer peripheral mountain retaining wall 1 into the ground, drives the casing to excavate the inside, and then casts concrete into the casing to cast in place. Along with the construction of the pile 2, the cast-in-place pile 2 is erected with a steel-made structural pillar 4 serving as the core material of the RC pillar 3 in the underground portion of the building, and then on the first floor above the structural pillar 4. After constructing the floor beam 5 etc. in advance, the underground part is sequentially excavated by using this as a support work, and the underground part is constructed using diagonal beams and horizontal cross beams, etc. Specifically, the foundation floor level (B2FL in the figure) is excavated, and the basement structure of the lowest underground layer including the footing 6 and the underground beam 7 is constructed around the above-mentioned structure column 4.

[0003]

By the way, in such a conventional method of constructing an underground portion, a high precision is required when the structural column 4 is built and fixed to the cast-in-place pile 2. However, there is a drawback in that the work requires a lot of work, such as filling the gravel around the true structural column 4 or removing the earth and sand entering the true structural column 4 at the time of excavation. In addition, since the connection rigidity between the cast-in-place pile 2 and the structural column 4 and horizontal resistance are insufficient, the footing 6
Had to be built, and there was a problem that complicated work would occur in the basic part.

Further, in order to construct the RC column 3 in the underground portion, it is necessary to temporarily install a separate formwork around the structural true column 4 and pour concrete, and as a result, anchor bolts to the structural true column 4 are formed. However, there is a problem in that construction of the RC column 3 also requires a lot of work because work such as embedding of the mold and temporary construction of the form takes place. As described above, in any of the conventional methods of constructing the underground portion, the construction of the foundation portion or the RC column 3 which is a joint portion between the pile head and the RC column 3 is complicated, and a great deal of trouble is required for these. As a result, there is a problem that the construction cost rises and the construction period becomes long.

The present invention can significantly reduce complicated work as compared with the prior art and is excellent in workability, and can improve the cross-sectional performance, the connection rigidity of the pile head to the foundation and the horizontal resistance. It is an object of the present invention to provide an underground pillar structure of a structure that becomes a structure and a method of constructing the underground pillar.

[0006]

According to a first aspect of the present invention, there is provided an underground column structure for a structure, wherein the underground column of the structure is integrally joined to an upper end portion of a steel pipe pile. (Hereinafter, referred to as CFT) or reinforced concrete-filled steel tubular columns (hereinafter, referred to as RCFT). Here, in the invention according to claim 2, the CFT or RCFT is formed to have the same outer diameter dimension as the steel pipe pile, and at least the CF is used.
The steel pipe portion of the T or RCFT is characterized in that it is built at the same time when the steel pipe pile is driven.

Further, in the method for constructing an underground pillar according to the present invention as defined in claim 3, the lower end of the steel pipe is joined and integrated with the upper end of the steel pipe pile, and then the steel pipe pile is driven at the same time. The above steel pipe is built, and concrete is filled and solidified in the steel pipe to form an underground pillar of the structure C
It is characterized by being FT or RCFT.

In this case, according to the invention of claim 4, a rotary press-fitting type steel pipe pile having the same diameter as the steel pipe is used as the steel pipe pile, and the steel pipe pile and the steel pipe are driven by a reverse driving method. Later, while constructing the skeleton of the underground portion, concrete is filled and solidified in the steel pipe to obtain the CFT or RCFT.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an underground column structure for a structure according to the present invention and an underground column construction method for constructing the same will be described below with reference to the drawings. As shown in FIG. 1, in the underground pillar structure of this structure, the underground pillar of the structure is constituted by RCFT 20. And this RCFT20 is the upper end part 21a of the steel pipe pile 21.
Is integrally joined by welding means such as semi-automatic welding having a joint metal fitting. Here, the steel pipe pile 21 is a rotary press-fitting type steel pipe pile having an outer diameter of 700φ to 1200φ, and a blade 21b for generating a propulsive force in a penetration direction at the time of rotary press-fitting is integrally formed at a lower end portion thereof. Has been formed.

The RCFT 20 is formed to have the same outer diameter as the steel pipe pile 21, and is built at the same time when the steel pipe pile 21 is placed. Depending on the conditions such as the depth of the underground part, the soil quality of the ground, and the acting axial force, RCF
CFT may be used instead of T20.

By the way, the CFT is a steel pipe filled with concrete, and the RCFT 20 is a steel pipe filled with reinforced concrete. These CF
T or RCFT20 is a member excellent in proof strength and deformability because the filled concrete or reinforced concrete prevents local buckling of the steel pipe and the steel pipe has a confined effect of restraining the concrete or reinforced concrete. is there. And RCFT
20, steel beams 22, 2 installed on each basement floor
A diaphragm 24 is joined to a portion that is continuous with the upper and lower flanges 3 so that the outer peripheral portion projects outward of the steel pipe.

Next, a method of constructing the underground pillar and the skeleton of the underground portion having the above-mentioned structure by the reverse construction method will be described with reference to FIGS. First, the lower end portion of the steel pipe that later constitutes the RCFT 20 is integrally joined to the upper end portion 21a of the steel pipe pile 21 by welding means such as semi-automatic welding having a joint metal fitting. Then, the steel pipe pile 21 to which the above-mentioned steel pipe is connected is driven by rotary press fitting.

Next, the diaphragm 24 is joined to the upper part of the steel pipe which becomes the true pillar, and the beam 22 on the first floor and the floor 3 are joined.
After constructing 0 etc. in advance, the underground part is primarily excavated by using this as a support work, the diaphragm 24 of the middle floor is sequentially joined, and the beam 23 and floor 31 of B1FL are constructed, and then secondary excavation is performed. Finally excavate to B2FL flooring level. By the way, in the present embodiment, B
Although shown in the case of a structure having 2FL as the bottom, the same can be applied to the case of a structure having an underground portion of B3FL or more.

At this time, an example of a method of constructing the beam 23 and the floor 31 in the BlFL will be described. First, as shown in FIG.
After arranging, the steel frame beam 23 in which the concrete 35 is cast is hung down in the part continuous with the panel zone, and is placed between the RCFTs 20. Next, the concrete 35 at the end is placed and positioned on the diaphragm 24 protruding from the outer periphery of the RCFT 20, and further, the panel zone reinforcement 36 and the slab reinforcement 37 are arranged, and the deck plate 38 is laid. Further, in parallel with this, a predetermined reinforcing bar arrangement such as inserting a reinforcing bar basket into the steel pipe is performed.

Next, concrete is press-fitted into the steel pipe from the lower part or filled with a tremie pipe from the upper part to solidify the RCFT20 as a pillar of the underground part of the structure, and In addition, as shown in FIG. 3, the concrete of the panel zone 39 and the floor slab 31 is poured and solidified, whereby the B1
Build the beam 23 and floor 31 in the FL. Incidentally, various forms can be adopted as another method of constructing the beam 23 and the floor 31. For example, the beam 23 may be a steel beam and may be joined to the outer periphery of the RCFT 20 using the diaphragm 24, or a flat slab may be used as the floor 31.

On the other hand, after finally excavating to the flooring level of B2FL, root cutting is performed and concrete is placed, whereby the underground beam 43 between the pressure plate 42 and the RCFT 20 of the pile head and the floor slab of the B2FL. Build 44.
In addition, reference numerals 40 and 41 in the figure respectively indicate a ceiling and an equipment duct to be installed later.

As described above, according to the underground pillar structure of the structure having the above structure and the method for constructing the underground pillar, since the steel pipe pile 21 is of the rotary press-fit type, the steel pipe pile is highly accurate. 21 can be placed, and the steel pipe portion of RCFT 20 which is a true pillar is also a steel pipe pile 21.
Since it is built at the same time when placing, the work for building the steel columns with fixed columns and fixing it to the pile head is no longer necessary, and finally with the same high precision as the steel pipe pile 21. The RCFT 20 can be built.

In addition, since the RCFT 20 has a higher sectional performance efficiency than the conventional RC column steel frame, it can exhibit excellent performance as a structural column in the upside down construction method. Moreover, since the steel pipe pile 21 and the RCFT 20 are integrally joined, the connection rigidity and horizontal resistance of the pile head to the foundation can be improved, and it is usually constructed to connect the foundation and the pile. Since no footing is required, the work around the pile head can be simplified.

Furthermore, since the RCFT 20 can be used as it is as a main pillar without requiring a refractory coating, the RCFT 20 has RC around the structure-column steel frame like a conventional RC pillar.
The work such as post-filling of the portion is not necessary, so that the complicated work such as embedding the steel column anchor bolt can be significantly reduced. As a result, throughout the construction of the foundation part and the underground column, it is possible to significantly reduce the complicated work compared to the conventional one, so that it is excellent in workability, and the cross-sectional performance and the connection rigidity and horizontal resistance of the pile head to the foundation are improved. It will be possible to improve.

[0020]

As described above, claim 1 or 2
According to the underground column structure of the structure according to claim 1 and the method for constructing an underground column according to claim 3 or 4, C is provided at the upper end of the steel pipe pile.
Since the steel pipe parts constituting the FT or RCFT are integrally joined, and at least the above steel pipes are built at the same time when the steel pipe pile is driven, the work for building and fixing the true-column steel frame as in the past Is unnecessary, and the CFT or RCFT can be finally installed with high accuracy.

Further, since the steel pipe pile and the CFT or RCFT are integrally joined, the connection rigidity and horizontal resistance of the pile head to the foundation can be improved, and the foundation and the pile are usually connected. Since the footing that is built for this purpose is not required, the work around the pile head can be simplified, and since CFT or RCFT does not require a fireproof coating, it can be constructed like a conventional RC column. The work of post-filling the RC portion around the pillar steel frame is not necessary, and thus the complicated work can be significantly reduced.

From the above, according to the underground pillar structure of a structure and the method for constructing an underground pillar according to the present invention, since the complicated work can be greatly reduced, the workability is excellent, and the sectional performance and The connection rigidity and horizontal resistance of the pile head to the foundation can be improved.

In this case, in particular, according to the invention of claim 4, since the rotary press-fitting type is used as the steel pipe pile, the steel pipe pile and the CFT can be driven with higher accuracy.
Alternatively, RCFT can be built. In addition, since the CFT or RCFT has higher cross-sectional performance efficiency than the conventional RC column steel frame, it can exhibit suitable performance as a structural column, and thus the invention according to claim 4. When it is applied to the upside down construction method as described above, a remarkable effect is obtained.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of an underground pillar structure of a structure according to the present invention.

FIG. 2 is a front view showing a joint structure between an RCFT and a steel frame beam.

FIG. 3 is a front view showing a state in which the panel zone and the floor slab of FIG. 2 are cast.

FIG. 4 is a front view showing a conventional reverse striking method.

[Explanation of symbols]

20 RCFT 21 steel pipe pile 21a Upper end 21b feather

Claims (4)

[Claims] 1. An underground pillar structure for a structure, characterized in that the underground pillar of the structure is constituted by a concrete-filled steel tube pillar or a reinforced concrete-filled steel tube pillar integrally joined to an upper end portion of a steel tube pile. 2. The concrete-filled steel pipe column or the reinforced concrete-filled steel pipe column is formed to have the same outer diameter dimension as the steel pipe pile, and at least the steel pipe portion of the concrete-filled steel pipe column or the reinforced concrete-filled steel pipe column is the steel pipe. The underground pillar structure for a structure according to claim 1, wherein the piles are built at the same time when the piles are laid. 3. The lower end of the steel pipe is joined to the upper end of the steel pipe pile.
A concrete-filled steel pipe column or a reinforced concrete-filled steel pipe column that becomes an underground column of a structure by integrating the steel pipe piles at the same time when the steel pipe piles are integrated and then building the steel pipe at the same time and further filling and solidifying concrete in the steel pipe A method of constructing an underground pillar, characterized by: 4. A rotary press-fitting steel pipe pile having the same diameter as the steel pipe is used as the steel pipe pile, and after the steel pipe pile and the steel pipe are driven by a reverse construction method, a skeleton of an underground portion is constructed, and The concrete is filled and solidified in the steel pipe to obtain the concrete-filled steel pipe column or the reinforced concrete-filled steel pipe column.
Construction method of the underground pillar described in.