JP2009007818A - Joint structure of column and pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure of a column and a pile dispensing with an underground beam and a footing by joining the column directly to a pile head, and suppressing a cost increase due to diameter enlargement of the pile and column to attain further cost reduction by preventing the transmission of seismic force to the pile to which the column is directly joined. <P>SOLUTION: In a building A wherein a floor on a first floor is formed of earthen floor concrete 9, the column 2 and the pile head are directly joined to each other, and a slit S isolating from the earthen floor concrete 9 is formed around a column base part 2a. In the case of the pile with a small diameter approximately equal to or less than a column diameter, a tie steel pipe 11 with a diameter larger than the pile diameter is installed around the pile head, and the pile head and the column base part are embedded in concrete 12 placed in the tie steel pipe to directly join both of them. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a column-to-pile joint structure in which a column beam and a foundation footing are omitted by directly joining a column to a pile head.

  By joining a pillar directly to a pile head, the joint structure of the pillar and a pile which abbreviate | omitted the underground beam and the foundation footing is already known by patent documents 1-4. According to these prior arts, when compared with a general pile foundation building in which underground beams and foundation footings are built on the pile heads and superstructure is built on these underground beams and foundation footings, By omitting the basic footing, it is possible to shorten the construction period and reduce the cost.

  However, in each of the above conventional examples, the column base portion of the column directly joined to the pile head is embedded in the first floor concrete and is integrated with the first floor (earth concrete). Therefore, the seismic force acting on the building is transmitted to the column base through the soil concrete, and is transmitted from the column base to the pile. In order to bear this seismic force, the pile diameter and the column diameter are changed. It was necessary to make it thicker.

JP 2000-291146 A JP 2004-162374 A JP 2001-329620 A JP 2007-63854 A

  The present invention has been made in view of the above-mentioned problems. The purpose of the present invention is to directly connect the column to the pile head, thereby omitting the underground beam and the foundation footing and directly connecting the column. An object of the present invention is to provide a column-to-pile joint structure that prevents the seismic force from being transmitted to the joined piles, suppresses an increase in cost due to the diameter increase of the piles and columns, and enables further cost reduction.

  The technical means taken by the present invention in order to achieve the above object are as follows. That is, the structure of the column-pile joint according to the first aspect of the present invention is a building in which the first floor is made of soil concrete, and the pillar and the pile head are joined directly, and the soil concrete is placed around the column base. It is characterized by forming slits for cutting edges.

  The invention according to claim 2 is the column-pile joint structure according to claim 1, wherein a connecting steel pipe having a diameter larger than the pile diameter is installed around the pile head, and the connecting steel pipe is disposed inside the connecting steel pipe. It is characterized in that the pile head and column base are embedded in the cast concrete.

  Invention of Claim 3 is the joining structure of the pillar and pile of Claim 1 or 2, Comprising: The said pillar is a middle pillar of the building which installed the earthquake-resistant element in the outer peripheral part, It is characterized by the above-mentioned.

  Invention of Claim 4 is the joining structure of the pillar and pile of Claim 1 or 2, Comprising: The said pillar is a pillar of the outer peripheral side of the building which installed the earthquake-resistant element in the center part, It is characterized by the above-mentioned. Yes.

According to the first aspect of the present invention, not only the underground beam and the foundation footing are omitted by joining the column directly to the pile head, but also the column base portion of the column joined directly to the pile head is Since the slit which cuts off the soil concrete on the floor is formed, the pile does not bear the seismic force, the increase in the cost due to the diameter increase of the pile or the pillar can be suppressed, and the cost can be further reduced. In addition, the seismic force can be efficiently borne by concentrating the seismic elements on the frame arranged at a position different from the directly joined pillars and piles. It can be planned.

  According to invention of Claim 2, the eccentric bending moment by the construction error of a pile can be processed with the earth pressure resistance of a ground through a connecting steel pipe. That is, when the pile diameter is considerably larger than the column diameter, the column base can be swallowed into the pile even if there is some error in the pile construction position, so the eccentric bending moment due to the pile construction error is Although it does not matter so much, if the pile foundation is a ready-made concrete pile, or if the pile diameter is small even if it is a steel pipe pile or cast-in-place concrete pile, the pile diameter is approximately the same as the column diameter, or the column diameter In such a case, if there is a displacement between the column and the pile due to the construction error of the pile, a bending moment due to the eccentricity of the column and the pile is generated at the pile head. However, according to the invention described in claim 2, a connecting steel pipe having a diameter larger than the pile diameter is installed around the pile head, and the pile head and the column base are embedded in the concrete cast inside the connecting steel pipe. Therefore, even if the underground beam and foundation footing effective for the treatment of the eccentric bending moment are omitted, the bending moment due to the eccentricity of the column and pile is connected and resisted by the earth pressure acting on the side of the steel pipe. And deformation of piles and pillars will be prevented.

  According to the invention described in claim 3, for the purpose of the building, since there are few openings such as windows on the outer periphery of the building, it is possible to install braces and earthquake-resistant walls as earthquake-resistant elements, but the interior increases the degree of freedom of space use. It is suitable for buildings such as commercial facilities and distribution warehouses where seismic walls cannot be installed for the purpose, and the construction period and cost of these buildings can be shortened.

  According to the invention described in claim 4, for example, it is suitable for a building having a center core for installing a roadway, a staircase, an elevator, etc. in the center of the building, such as a parking lot building or an office building. It is possible to shorten the construction period and cost of the building.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an example of a column-pile joint structure according to the present invention. Reference numeral 1 denotes a cast-in-place concrete pile which is an example of a pile, and 2 is a column (a column made of precast concrete, but may be a steel column using a steel pipe or a shape steel), and the column 2 and the pile head 1a. The ground beam and the foundation footing are omitted by directly joining.

  Specifically, after the cast-in-place concrete pile 1 is constructed, the low-quality pile head concrete mixed with slime is scraped off to expose the anchoring rebar 3 above the reinforcing bar rod. Thereafter, the steel pipe 4 is driven around the pile head 1a. After completing the construction of the pillar 2, the concrete 6 is embedded in the steel pipe 4 so that the fixing rebar 5 provided on the lower surface of the column base 2 a and the fixing rebar 3 of the pile head 1 a are embedded. Has been laid. 7 is a temporary piece for securing the position of the column base 2a, and is fixed to the upper end of the steel pipe 4 by means such as welding. 8 is backfill soil, and 9 is soil concrete on the first floor.

A slit S is formed around the column base 2a to cut off the soil concrete 9. The slit S may be an annular cavity. However, in the illustrated embodiment, the slit S functions as a weir plate (end face formwork) when the soil concrete 9 is placed around the column base 2a. And in the state where a soft or fragile embedded member (for example, a member such as a foamed polystyrene molded product or a polystyrene foamed product) a that is easily deformed or broken by a seismic force is placed, the soil concrete 9 is placed, The slit S is formed by the embedded member a. 9a is a floor finish having a strength that does not prevent deformation or destruction of the embedded member a due to seismic force. For example, a plastic tile, a waterproof coating, or the like is used.

  Although not shown, instead of the cast-in-place concrete pile 1, a ready-made concrete pile having a diameter larger than the column diameter may be placed. Further, instead of the cast-in-place concrete pile 1, a steel pipe pile may be placed and the column 2 may be directly joined to the pile head 1a. In this case, a circular partition plate for receiving the cast-in-place concrete is fixed inside the pile head 1a of the steel pipe pile by means of welding or the like, and after the construction of the pillar 2 is completed, the pile head 1a of the steel pipe pile is completed. By placing the concrete 6 in a state in which the fixing reinforcing bars 5 provided on the lower surface of the column base 2a are buried, the column 2 is directly joined to the pile head 1a.

  According to the above configuration, by directly joining the column 2 to the pile head 1a, not only the underground beam and the foundation footing are omitted, but also around the column base 2a of the column 2 joined directly to the pile head 1a. Since the slit S that cuts off the soil concrete 9 on the first floor is formed, even if an earthquake force acts on the building, it will not be transmitted from the soil concrete 9 to the column base 2a, and the pile will produce an earthquake force. Therefore, the pile and the pillar 2 can be set to have a cross-sectional area sufficient to bear a vertical load.

  Therefore, in addition to shortening the construction period and cost by omitting underground beams and foundation footings, it is possible to further reduce costs by suppressing an increase in cost due to thickening of piles and columns. In addition, the seismic force can be efficiently borne by concentrating the seismic elements on the frame arranged at a position different from the directly joined pillars and piles. It can be planned.

  FIG. 3 shows another embodiment of the present invention. This embodiment is a pile having a small pile diameter that is substantially the same as the column diameter or less than the column diameter (in the illustrated example, a ready-made concrete pile, but may be a steel pipe pile or a cast-in-place concrete pile. ) By installing a connecting steel pipe 11 having a diameter larger than the pile diameter around 10 pile heads 10a, and placing the pile head 10a and the column base 2a in the concrete 12 placed inside the connecting steel pipe 11, It is characterized in that the pillar 2 and the pile head 1a are directly joined. Reference numeral 30 denotes a fixing reinforcing bar planted on the annular end plate at the upper end of the pile 10.

  According to the above configuration, even if the position of the pillar and the pile is displaced due to the construction error of the pile, the eccentric bending moment due to the construction error of the pile is caused to be generated by the soil of the ground via the connecting steel pipe 11. It can be processed with a pressure resistance. Since other configurations and operations are the same as those of the embodiment of FIGS. 1 and 2, the same components are denoted by the same reference numerals, and description thereof is omitted.

  4 and 5 are schematic cross-sectional plan views of a building to which the column-pile joint structure according to the present invention described with reference to FIGS. 1 to 3 is applied. Is characterized in that the pillar 2 directly joined to the pile head is the middle pillar of the building in which the seismic elements are installed on the outer periphery. In the building shown in FIG. 5, the pillar 2 joined directly to the pile head is earthquake resistant. It is a pillar on the outer peripheral side of the building where the element is installed in the center. In the figure, S is a slit that cuts off the soil concrete 9. Reference numeral 20 denotes a pillar that bears the seismic force, and a foundation footing 13 is constructed under the pillars and is connected by an underground beam 14.

  The building shown in Fig. 4 can be installed with braces and earthquake-resistant walls as earthquake-resistant elements because there are few openings such as windows on the outer periphery of the building due to the use of the building. The building shown in FIG. 5 has a center core that installs roads, stairs, elevators, etc. in the center of the building, such as a parking lot building or an office building. It is a building.

It is a vertical side view which shows one Embodiment of this invention. It is a cross-sectional top view of the principal part. It is a vertical side view which shows other embodiment. It is a typical cross-sectional top view of the building to which the junction structure of the pillar and pile concerning this invention was applied. It is a typical cross-sectional top view of the building to which the junction structure of the pillar and pile concerning this invention was applied.

Explanation of symbols

1 pile (cast-in-place concrete pile)
DESCRIPTION OF SYMBOLS 1a Pile head 2 Column 2a Column base 3 Reinforcing bar 4 Steel pipe 5 Reinforcing bar 6 Concrete 7 Temporary piece 8 Backfill soil 9 Dough concrete 10 Pile 10a Pile head 11 Joint steel pipe S Slit a Embedded member

Claims (4)

  In a building with ground floor concrete on the first floor, a pillar and pile joint structure characterized in that a pillar and a pile head are directly joined, and a slit is formed around the column base to cut out the soil concrete.   The pillar-to-pile joint structure according to claim 1, wherein a connecting steel pipe having a diameter larger than the pile diameter is installed around the pile head, and the pile head and the pillar are placed in the concrete cast in the connecting steel pipe. A pillar-pile joint structure characterized by embedded legs.   The pillar-pile joint structure according to claim 1 or 2, wherein the pillar is a middle pillar of a building in which a seismic element is installed on the outer periphery.   The column-pile joint structure according to claim 1 or 2, wherein the column is a column on the outer peripheral side of a building in which a seismic element is installed in the center.

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