JP2012057431A - Structure for connecting pile and steel column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for connecting a pile and a steel column which enables a pile diameter to be decided regardless of a fixing state of a base section of a steel column, can suppress an increase in a construction cost and can absorb a construction error in a horizontal position of a pile head.SOLUTION: A structure for connecting a pile and a steel column is configured so that a pile 1 has edge plate members 11 positioned close to an upper end thereof to fix reinforcement, and a steel column 2 has a constant cross section portion 21 having almost a constant section size, a small cross section portion 22 positioned at a lower end of the steel column 2 with the section size smaller than the constant cross section portion 21, and a connection plate 23 connected to the lower end of the constant cross section portion 21 as well as an upper end of the small cross section portion 22. The steel column 2 is arranged so that a lower surface 22b of the small cross section portion 22 is positioned directly above the pile 1. A reinforcement cage 41 is assembled around the small cross section portion 22 of the steel column 2 with lower ends of vertically extended main reinforcement 42 fixed to the edge plate members 11 of the pile 1. A reinforced concrete structure 4 is constructed by placing concrete 44 in a manner that encases the main reinforcement 42 up to a lower surface 23b of the connection plate 23.

Description

  The present invention relates to a joint structure between a pile and a steel column, and more particularly to a joint structure suitable for directly joining a pile and a steel column without providing a foundation beam or a footing.

  Conventionally, pile foundations in steel buildings have been constructed with multiple piles in the ground so that the pile heads are located at a position below the slab surface of the lowest floor, and footing is performed so that the pile heads of each pile are involved. In general, the footings are connected and integrated with underground beams, and then the pillars of the building are joined to the footings. However, in recent years, a structure in which a pile and a column are directly joined without providing a footing and an underground beam has begun to be adopted. According to this structure, it is possible to greatly shorten the construction period and reduce the cost.

  As such a direct connection structure between a pile and a column, a base plate is provided at the bottom of the column, and a bending stress is transmitted by embedding it in the inside of the pile head with a lower leg portion below the base plate, An invention was proposed in which axial force is transmitted from the base plate to the pile head by supporting the base plate on the anchor bolt protruding from the top surface of the pile head and filling mortar between the pile head and the base plate. (See Patent Document 1).

  In addition, if the steel column legs are inserted into the pile head, the pile diameter may become larger than necessary. As a joint structure to improve this, the top end plate of the PHC pile is the same as the PHC pile. There has also been proposed an invention in which a steel pipe having a diameter is joined and concrete is filled in the steel pipe in a state where the legs of the steel column are inserted into the steel pipe (see Patent Document 2).

  In addition, in order to be able to determine the pile diameter regardless of the fit of the steel column base, a pile head joint plate with a shape corresponding to the base plate of the steel column is installed on the pile head, and the base plate is used as the pile head joint plate. The steel columns are directly and coaxially joined to the piles by fixing them with bolts and nuts that can be adjusted in height, with the gaps facing each other, and the reinforcing bars are placed around the joints. An invention has been proposed in which a reinforced concrete structure is constructed after the reinforcement (see Patent Document 3).

Japanese Patent No. 3671342 Japanese Patent No. 3800535 JP 2002-188154 A

  However, in the joint structure of Patent Document 3, in order to construct a reinforced concrete structure by arranging reinforcing bars so as to surround the joint part, it must be excavated considerably deeper than the joint part, and ground excavation for joining work The amount increases. In addition, deeper excavation may require temporary equipment such as a mountain stop depending on the ground conditions. Therefore, an increase in excavation-related costs is inevitable. Moreover, when a construction error occurs in the horizontal position of the pile head, there is a possibility that the steel column cannot be joined to the pile.

  The present invention has been made in view of such a background, and it is possible to determine a pile diameter regardless of the column fit, to suppress an increase in construction cost, and to cope with a construction error at a pile head position. An object of the present invention is to provide a joint structure between a steel column and a steel column.

  In order to solve the above-mentioned problems, the present invention provides a structure in which a pile (1) and a steel column (2) are joined, and the pile has a metal portion (end plate member 11) used for fixing a reinforcing bar in the vicinity of the upper end. The steel column has a constant cross-sectional portion (21) having a substantially constant cross-sectional dimension, a small cross-sectional portion (22) disposed at the lower end and having a cross-sectional dimension smaller than the constant cross-sectional portion, and a lower end of the constant cross-sectional portion And a joining plate (23) to which the upper end of the small cross section is joined, and the steel column is arranged so that the lower surface (22b) of the small cross section is located immediately above the pile, Around the small cross section, the lower end of the pile is fixed to the metal part of the pile and the main bar (42) extending in the vertical direction is provided. The concrete (44) around which the main bar is wound is connected to the lower surface (23b) of the joining plate (23). Reinforced concrete structure (4) is constructed to reach Configured to.

  When constructing a concrete structure that surrounds the legs of a steel column, the cross-sectional dimension of the reinforced concrete structure is larger than the cross-sectional dimension of the column, and when the lower end of the reinforcing bar is fixed to the pile, the cross-sectional dimension of the pile also increases. According to the present invention, since the leg portion (small cross-section portion) of the steel column has a smaller cross-sectional dimension than the other portion (constant cross-section portion), the reinforced concrete is used regardless of the dimensions of the steel column (constant cross-section portion). The cross-sectional dimension of the structure can be reduced. Therefore, even if the form which fixes the lower end of a reinforcing bar to a pile is adopted, the section size of a pile can be made small regardless of the size of a steel column. On the other hand, if the cross-sectional dimension of the pile is small, the horizontal construction error of the pile that is allowed to place the steel column directly above the pile is small, but the steel column has a small cross section, so the horizontal direction of the pile Even if the construction error increases, the pile and the steel column can be joined via the reinforced concrete structure with the lower surface of the steel column placed directly above the pile. In addition, in the reinforced concrete structure as the root winding concrete, since the lower end of the main reinforcement is fixed to the metal part of the pile, the height of the concrete to be placed around the pile head (down dimension from the pile head surface) is reduced. be able to. Therefore, the amount of ground excavation around the pile head can be reduced.

  Moreover, according to one side of this invention, the temporary support member (3) for supporting a steel column at the time of construction is arrange | positioned between the pile head surface (1a) of a pile, and the small cross-section part of a steel column. It can be set as the structure made.

  According to this configuration, since the steel column can be supported by the temporary support member, the work of building the steel column is easy. Even if a vertical construction error occurs at the pile head position, the steel column can be easily arranged at an appropriate height by adjusting the length of the temporary support member.

  Further, according to one aspect of the present invention, the steel column can further include a protruding portion (stud 24) protruding in a substantially horizontal direction from the side surface (22s) of the small cross-sectional portion.

  According to this structure, the fixing part with respect to the reinforced concrete structure of a steel column can be heightened because a protrusion part engages with concrete.

  Further, according to one aspect of the present invention, the metal portion (11) has a cylindrical portion (11b) that constitutes a part of the outer peripheral surface (1s) of the pile, and the main reinforcement is on the outer surface of the cylindrical portion. It is fixed by welding, and the reinforced concrete structure can be configured to have a larger cross-sectional shape than the pile.

  According to this configuration, for example, when a foundation beam connected to a reinforced concrete structure is constructed, it is considered that the reinforcement of the foundation beam interferes with the main bar extending in the vertical direction. Is fixed to the cylindrical member by welding, so that the interference with the reinforcing bars of the foundation beam can be avoided to some extent by shifting the welding position.

  Moreover, according to one aspect of the present invention, the metal portion (11) has an annular flat plate portion (11a) that constitutes a pile head surface (1a) of a pile and has an internal thread hole (12), The male screw portion (42a) that is screwed into the female screw hole of the flat plate portion is provided at the lower end, and the nut (45) screwed to the male screw portion is fixed by the tightening force with respect to the end plate member. it can.

  According to this configuration, since the main reinforcement can be fixed to the end plate member without performing welding, it is not necessary to consider the construction conditions such as the weather, and the construction can be facilitated. In addition, by mechanically fixing the female screw hole of the flat plate portion and the male screw portion of the main bar, both can be securely fixed.

  As described above, according to the present invention, it is possible to determine the pile diameter regardless of how the pillars are accommodated, to suppress an increase in the construction cost, and to connect the pile and the steel column that can cope with the construction error at the pile head position. Structure can be provided.

It is sectional drawing of the junction structure of the pile and steel column which concern on 1st Embodiment. FIG. 2 is a cross-sectional view showing a part through II-II line in FIG. 1. It is sectional drawing which follows the III-III line | wire in FIG. It is sectional drawing of the joining structure of the pile and steel column which concern on 2nd Embodiment. FIG. 5 is a cross-sectional view showing a part through the line VV in FIG. 4.

  Hereinafter, an embodiment of a joint structure between a pile 1 and a steel column 2 according to the present invention will be described with reference to the drawings.

<< First Embodiment >>
First, the joint structure between the pile 1 and the steel column 2 according to the first embodiment will be described with reference to FIGS. In addition, in FIG. 2, the concrete 44 of the upper part of the pile 1 is shown through, and the said part is shown without giving hatching. The same applies to FIG. 5 relating to the second embodiment.

  As shown in FIG. 1, the connection structure of the pile 1 and the steel column 2 which concerns on this invention is made to support the one steel column 2 on the one pile 1, Here, a reinforced concrete structure The joint portion constituted by the body 4 is set at a position lower than the floor surface 5 on the lowest floor (here, the first floor).

  The pile 1 is a PHC pile (pre-tension type high-strength prestressed concrete pile), and includes metallic end plate members 11 arranged at the upper and lower ends in order to maintain the tension applied to a PC cable (not shown) at the time of manufacture. ing. The end plate member 11 is connected to a ring-shaped flat plate portion 11a that defines an upper surface of the pile 1 (hereinafter referred to as a pile head surface 1a) and an outer peripheral edge of the ring-shaped flat plate portion 11a. It is comprised from the cylindrical part 11b which defines the upper part.

  The steel column 2 has a constant cross-sectional portion 21 having a constant cross-sectional dimension, a small cross-sectional portion 22 disposed at the lower end and having a smaller cross-sectional dimension than the constant cross-sectional portion 21, and a lower end of the constant cross-sectional portion 21 by welding in a factory. And a joining plate 23 to which the upper end of the small cross-section portion 22 is joined, and the lower surface 22b of the small cross-section portion 22 is disposed so as to be located immediately above the pile head surface 1a.

  As shown in FIG. 2, the constant cross-section portion 21 is a hollow quadrangular column having a substantially square cross section, and the joining plate 23 is a flat plate having a substantially square shape having a plane dimension larger than that of the constant cross section portion 21. It is. On the other hand, as shown in FIG. 3, the small cross section 22 is a column made of H-section steel, and a plurality of studs 24 projecting in a substantially horizontal direction are planted on the outer surface 22 s at the intermediate position in the height direction. ing.

  Returning to FIG. 1, a temporary support member 3 is disposed between the pile 1 and the steel column 2. The temporary support member 3 has a lower end in contact with the pile head surface 1 a of the pile 1 and an upper end in contact with the lower surface 2 b of the steel column 2. The temporary support member 3 has a smaller outer dimension than the pile 1 in plan view, and can be used to support the steel column 2 when the steel column 2 is built as will be described later. The temporary support member 3 is joined to a column portion 31 made of H-shaped steel having a cross-sectional dimension comparable to that of the small cross-sectional portion 22 of the steel column 2 and the upper end of the column portion 31, and A top plate 32 formed in a substantially square shape having a plane dimension larger than the cross-sectional dimension, and a base plate 33 joined to the lower end of the column portion 31 and formed in a substantially circular shape having a plane dimension slightly smaller than the cross-sectional dimension of the pile 1. It consists of.

  A reinforced concrete structure 4 for joining the steel column 2 and the pile 1 is constructed around the small cross section 22 of the steel column 2 and the temporary support member 3. The reinforced concrete structure 4 has a lower end fixed to the upper end plate member 11 of the pile 1 and extends in the vertical direction, and surrounds the main bars 42 with a plurality of main bars 42 arranged at predetermined intervals in the horizontal direction. It has a reinforcing bar 41 composed of a plurality of hoop bars 43 arranged horizontally at predetermined intervals in the direction, and the concrete 44 having a circular cross section around which the reinforcing bar 41 is wound is higher than the lower surface 23b of the joining plate 23 of the steel column 2. It is constructed so as to support the lower surface 23b of the bonding plate 23 up to the height (here, the upper surface height). Therefore, the reinforced concrete structure 4 is formed in a larger cross-sectional dimension than the pile 1. In the present embodiment, the main reinforcement 42 is fixed to the cylindrical portion 11b of the end plate member 11 by field welding.

  According to the joint structure between the pile 1 and the steel column 2 configured as described above, the axial force of the steel column 2 is transmitted from the joint plate 23 and the small cross section 22 through the reinforced concrete structure 4 and the temporary support member 3 to the pile 1. The pile 1 and the steel column 2 are integrated by the reinforced concrete structure 4. In addition, since the small cross-sectional portion 22 of the steel column 2 has a smaller cross-sectional dimension than the constant cross-sectional portion 21, the reinforced concrete structure 4 of the steel column 2 is independent of the cross-sectional dimension of the steel column 2 (the cross-sectional dimension of the constant cross-sectional portion 21). The cross-sectional dimension can be reduced. Therefore, even if the form in which the lower end of the main bar 42 is fixed to the pile 1 is adopted, the cross-sectional dimension of the pile 1 can be reduced regardless of the cross-sectional dimension of the steel column 2.

  On the other hand, when the cross-sectional dimension of the pile 1 becomes small, the horizontal construction error of the pile 1 allowed to arrange the steel column 2 directly above the pile 1 becomes small, but the steel column 2 has the small cross-section part 22. Therefore, even if the construction error in the horizontal direction of the pile 1 becomes large, the pile 1 and the steel column 2 are joined via the reinforced concrete structure 4 with the lower surface 22b of the small cross section 22 arranged immediately above the pile 1. It becomes possible. In addition, since the top plate 32 of the temporary support member 3 has a plane dimension larger than the cross-sectional dimension of the small cross-sectional portion 22 of the steel column 2, even if a horizontal construction error occurs in the pile head position, By arranging the steel column 2 at a position offset from the axis of the support member 3, horizontal construction errors can be absorbed. In addition, when a vertical construction error has occurred at the pile head position, an optimum height dimension is selected from a plurality of temporary support members 3 having different height dimensions prepared in advance, The vertical construction error of the pile 1 can be absorbed by adjusting the height dimension so as to absorb the construction error in the vertical direction after the pile 1 is installed and processing the temporary support member 3.

  Moreover, since the lower end of the main reinforcement 42 is fixed to the end-plate member 11 of the pile 1, the reinforced concrete structure 4 as a root winding concrete is the height of the concrete 44 cast around the pile head (from the pile head surface 1a). ) Can be reduced. Therefore, the amount of excavation of the ground G around the pile head is reduced. If the reinforced concrete structure 4 is constructed so that the upper surface is located above the slab on the lowest floor, the excavation amount of the ground G can be further reduced.

  On the other hand, the stud 24 projecting in a substantially horizontal direction is planted on the outer surface 22s of the small cross section 22 of the steel column 2 so that the stud 24 and the concrete 44 are engaged with the reinforced concrete structure 4 of the steel column 2. The fixing force is increased, and the small cross section 22 can be shortened.

  Furthermore, since the temporary support member 3 is disposed between the pile head surface 1a of the pile 1 and the small cross section 22 of the steel column 2, the steel column 2 can be supported by the temporary support member 3. The building work of the steel column 2 is easy. Even if a vertical construction error occurs at the pile head position, the steel column 2 can be easily arranged at an appropriate height by adjusting the length of the temporary support member 3.

  Further, for example, when the foundation beam is constructed so as to be connected to the reinforced concrete structure 4, it is considered that the reinforcement of the foundation beam interferes with the main reinforcement 42, but the end plate member 11 has the cylindrical portion 11b, Since the main bars 42 are fixed to the cylindrical portion 11b by welding, it is possible to avoid interference with the reinforcing bars of the foundation beam to some extent by shifting the welding position.

<< Second Embodiment >>
Next, the joining structure and joining method of the pile 1 and the steel column 2 which concern on 2nd Embodiment with reference to FIG. 4, FIG. 5 are demonstrated. In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment, and the description which overlaps with 1st Embodiment is abbreviate | omitted.

  As shown in FIGS. 4 and 5, this embodiment is different from the first embodiment in that the lower end of the main bar 42 is fixed to the ring-shaped flat plate portion 11 a of the end plate member 11 of the pile 1. More specifically, in the ring-shaped flat plate portion 11a of the end plate member 11, a plurality of female screw holes 12 are formed at predetermined intervals so as to form a circle along the outer peripheral edge of the pile 1. On the other hand, a male screw portion 42a that is screwed into the female screw hole 12 is formed at the lower end portion of the main bar 42, and a nut 45 is screwed onto the male screw portion 42a. Then, by tightening the nut 45 toward the ring-shaped flat plate portion 11a in a state where the male screw portion 42a of the main bar 42 is screwed into the female screw hole 12 of the ring-shaped flat plate portion 11a, the tightening force of the nut 45 on the end plate member 11 is tightened. Thus, the main bar 42 is fixed to the pile 1.

  According to the joining structure of the pile 1 and the steel column 2 configured as described above, the main reinforcement 42 can be fixed to the end plate member 11 without performing welding, so it is not necessary to consider the construction conditions such as the weather. Is easy. Moreover, since it is mechanical fixing, the main reinforcement 42 is reliably fixed to the end plate member 11. Moreover, since the diameter of the reinforcing bar 41 is smaller than that of the first embodiment, the cross-sectional dimension of the reinforced concrete structure 4 can be reduced, and the material cost and the excavation amount of the ground G can be reduced.

  Thus, according to the joint structure between the pile 1 and the steel column 2 according to the first and second embodiments, the pile diameter can be determined regardless of the accommodation of the steel column 2, and the increase in construction cost can be suppressed. Furthermore, the construction error of the pile head position can be absorbed and the steel column 2 can be arranged at an appropriate position.

  This is the end of the description of specific embodiments, but the present invention is not limited to these embodiments. For example, in the above embodiment, the temporary support member 3 is disposed on the pile head surface 1a in order to support the steel column 2 at the time of erection, but the temporary support member 3 may not be disposed. In this case, the concrete 44 may be placed in a state where the steel column 2 is placed and temporarily fixed at an appropriate position using a gantry or the like regardless of the vertical construction error of the pile head position. Moreover, in the said embodiment, although the stud 24 is provided in the outer surface 22s of the small cross-section part 22 of the steel column 2, it is a rib so that it may protrude substantially horizontally from the inner surface of the small cross-section part 22 instead of the stud 24. Or an end plate may be provided at the lower end of the small cross section 22. Or it is also possible to make it the form which does not provide such a protrusion part. Moreover, in the said embodiment, although the foundation beam is not provided, it is also possible to provide a foundation beam and it is also possible to provide a footing around a junction part. In addition to these changes, the specific shape and arrangement of each member are not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Pile 1a Pile head surface 1s Outer peripheral surface 2 Steel column 3 Temporary support member 4 Reinforced concrete structure 11 End plate member (metal part)
11a Ring-shaped flat plate portion 11b Cylindrical portion 12 Female screw hole 21 Constant cross section 22 Small cross section 22b Lower surface 22s Side surface 23 Joining plate 23b Lower surface 24 Stud (projection)
42 Main reinforcement 42a Male thread 44 Concrete 45 Nut G Ground

Claims (5)

It is a joint structure between a pile and a steel column,
The pile has a metal part used for fixing the reinforcing bars in the vicinity of the upper end,
The steel column is joined to a constant cross-sectional portion having a substantially constant cross-sectional dimension, a small cross-sectional portion disposed at the lower end, having a cross-sectional dimension smaller than the constant cross-sectional portion, and a lower end of the constant cross-sectional portion and Having a joining plate to which the upper end of the small cross-section part is joined,
The steel column is arranged so that the lower surface of the small cross-sectional portion is located immediately above the pile,
Around the small cross section of the steel column, the lower end is fixed to the metal portion of the pile and has a main bar extending in the vertical direction, and the concrete in which the main bar is wound is hit so as to reach the lower surface of the joining plate. A joint structure between a pile and a steel column, characterized by the construction of a reinforced concrete structure.   The temporary support member for supporting the said steel column at the time of construction is arrange | positioned between the pile head surface of the said pile, and the small cross-section part of the said steel column, It is characterized by the above-mentioned. Joint structure of pile and steel column.   The said steel column further has the protrusion part which protrudes in a substantially horizontal direction from the side surface of the said small cross-section part, The joining structure of the pile and steel column of Claim 1 or Claim 2 characterized by the above-mentioned. The metal part has a cylindrical part constituting a part of the outer peripheral surface of the pile,
The main reinforcement is fixed to the outer surface of the cylindrical portion by welding,
The said reinforced concrete structure has a larger cross-sectional shape than the said pile, The joining structure of the pile and steel column as described in any one of Claims 1-3 characterized by the above-mentioned. The metal portion has an annular flat plate portion that forms a pile head surface of the pile and has a female screw hole,
The main bar has a male screw portion screwed into a female screw hole of the flat plate portion at a lower end, and is fixed by a tightening force of a nut screwed to the male screw portion to the flat plate portion. The joint structure of the pile and steel column as described in any one of Claims 1-3.

Images