JP2005076330A - Connection structure of pile and post - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the connection structure of a pile and a post reducing a bending moment in the connecting section of the pile and the post while easily arranging bars accurately without a congestion in the connection structure of the reinforced concrete-constructed pile and post. <P>SOLUTION: In the reinforced concrete-constructed pile 1 and the post 2, upper and lower sections are connected by steel pipes 3 buried and fixed in the concrete of the pile 1 and the post 2 while the end sections of footing beams 8 are connected at the central sections of the steel pipes 3. The connecting section of the pile 1 and the post 2 is constituted so that the upper end of the bar 1a for the pile 1 and the lower end of the bar 2a for the post 2 are separated without a connection, and the connecting section of the pile 1 and the post 2 is formed on a connecting section 9 connected by a short-pipe section at the central section of the steel pipe 3. The connecting section of the pile 1 and the post 2 is further constituted so that the bending moment on the pile-head section side in the case of the occurrence of an earthquake is reduced by the ductility of the short-pipe section of the steel pipe 3 while the bar arrangement works of the pile 1 and the post 2 are conducted easily and accurately. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a connection structure between a reinforced concrete pile and a column in a concrete structure.

  A pile as a foundation in a concrete structure normally supports the load of the concrete structure acting in the vertical direction, but when an earthquake occurs, a horizontal force acts on the pile in addition to the vertical force. As a result, a large bending moment is generated at the joint between the pile and the column standing on the pile. For this reason, a footing is conventionally provided on the pile head, and the cast-in-place reinforced concrete pile and the foundation beam are connected via this footing, and the bottom end of the column is connected to the footing while penetrating the foundation beam. Although it has a load bearing structure, in such a connection structure between a pile and a column, the joint between the pile and the column becomes stiff and the bending moment cannot be reduced. There is a problem that the line work becomes complicated.

  On the other hand, in order to reduce the bending moment generated at the joint between the pile and the column in the concrete structure, the connection structure is made a flexible structure close to pin coupling. That is, with the bottom surface of the structure (foundation beam) spaced apart upward from the upper end surface of the cast-in-place concrete pile, the lower part of the column steel frame in the steel reinforced concrete column of this structure is buried in the pile head concrete. By using a structure in which the upper end surface of the head and the lower surface of the structure are connected by the column steel, the bending moment is reduced at the short length of the column steel existing in the gap between the pile head and the structure. (For example, refer to Patent Document 1).

JP 2000-144904 A (pages 3 to 5, FIG. 1).

  However, according to the connection structure between the pile and the column, the lower part of the column steel frame is buried in the concrete of the pile head, so that the column is always applied only to a concrete structure having a smaller diameter or thinner than the pile. In addition, the reinforcement of the column surrounding the column steel is also embedded in the concrete of the pile head together with the column steel, so the presence of this reinforcement increases the rigidity of the joint between the pile and the column. There is a problem that it still becomes high and the effect of reducing the bending moment is small.

  In addition, it is difficult to place the bar at the joint between the lower part of the column reinforcement and the reinforcement at the head of the pile. Especially when the pile is cylindrical and the column is prismatic, the pile reinforcement is arranged in a circular shape. At the joint between the reinforcing bar and the column reinforcement arranged in a rectangular shape, the foundation beam reinforcement is crossed and the reinforcement is very congested. There is a problem that it is difficult to arrange the bars accurately, and further, the placement work of the concrete after the bar arrangement is difficult.

  The present invention has been made in view of the above problems, and the object of the present invention is to reliably support the column of the concrete structure by the pile and then to determine the bending moment of the connecting portion between the pile and the column. Even if the pile and the column are approximately the same diameter or the same thickness as much as possible, and even if the pile is a columnar shape and the column is a prismatic shape, the bar arrangement work can be performed efficiently and accurately. It is in providing the connection structure of a pile and a pillar.

  In order to achieve the above object, the connection structure of a pile and a column according to the present invention includes a reinforced concrete pile and a reinforced concrete column having a certain length that is narrower than these piles and columns. A pile-column connection structure that is integrally connected by a steel pipe of the above-mentioned steel pipe with a central portion in the length direction of the steel pipe arranged at the connection portion between the upper end surface of the pile and the lower end surface of the column. The upper part and the lower part of the reinforced concrete column are fixed in an embedded state in the concrete at the center of the cross section of the upper end of the reinforced concrete column and the center of the cross section of the lower end of the pile, respectively, and surround the steel pipe. The lower end of the column reinforcing bar and the upper end of the pile reinforcing bar are separated from each other without being connected.

  In the connection structure between a pile and a column according to claim 1, the invention according to claim 2 is characterized in that a lower beam reinforcement projecting piece is attached to the side surface of the central part in the length direction of the steel pipe and the central part. The upper beam reinforcement projecting piece is attached to the upper side surface, and the upper projecting piece is provided with a hole through which the lower end of the reinforcing bar of the column surrounding the upper part of the steel pipe is inserted, The lower end of the above-mentioned reinforcing bar hanging down from the lower end of the column through this hole is received by the upper surface of the lower projecting piece, and the lower surface of the lower projecting piece is connected to the upper end surface of the reinforcing bar of the pile. It has a structure that is separated without any.

  The invention according to claim 3 is characterized in that the reinforcing bar insertion hole provided in the upper protruding piece is formed in a cutout hole opened on the protruding end face side of the protruding piece.

  Further, in the invention according to claim 4, when the horizontal length due to an earthquake or the like is applied, the insertion length to the columns and piles in the upper and lower portions of the steel pipe is equalized and the arrangement length is equalized. It is formed in the length which can resist the pulling-out force from a pile.

  The invention according to claim 5 is characterized in that the pile is cylindrical and the column is prismatic.

  According to the invention which concerns on Claim 1, the upper end part of a reinforced concrete structure pile and the lower end part of the reinforced concrete structure column supported by this pile are the upper part of a steel pipe smaller in diameter or thinner than these piles and a pillar. Since the lower part of the column is fixed in the embedded state in the concrete and the lower part is fixed in the embedded state of the pile head in the embedded state, the column is firmly fixed on the pile via this steel pipe. It is possible to construct a connection structure between a pile and a column that is connected to and supported by the pipe, and the lower end of the column reinforcing bar surrounding the steel pipe is separated from the upper end of the pile reinforcing bar. There is only a central part of the steel pipe protruding from the upper end surface of the pile head at the connection between the pile and the column, and there is a reinforcing bar connecting the pile head and the lower end of the column around it. Since this connection structure does not exist, this connection part Becomes soft structure having a toughness can be reduced reinforcement amount it is possible to reduce the bending moment acting on the connecting portion when the earthquake occurred, perform well working reinforcement and the like efficiency.

  According to the invention according to claim 2, in the connection structure between the pile and the column, the lower beam reinforcement mounting protrusion is provided on the side surface of the central portion of the steel pipe in which the lower end portion of the column and the beam are integrated. Since the upper beam reinforcement projecting piece is attached to the side surface above the center part with the piece attached, when constructing a reinforced concrete beam with these upper and lower projecting pieces, the reinforcement work is not performed. The bar can be easily arranged at an accurate position, and the upper projecting piece is provided with a hole through which the lower end of the reinforcing bar of the column surrounding the upper part of the steel pipe is inserted and from the lower end of the column Since the lower end of the above-mentioned reinforcing bar hanging down through this hole is received on the lower projecting piece, when constructing a reinforced concrete column, the main reinforcement is also arranged horizontally and vertically. Can be done efficiently in the exact position of the column, under the main bar The separation width between main reinforcement upper end of the pile can also be taken to ensure.

  In addition, as described above, since the lower end of the column reinforcement and the upper end of the pile reinforcement are separated from each other without being connected, the reinforcement of the column reinforcement and the reinforcement of the pile are arranged independently without being congested. In particular, even when the pile has a columnar shape and the column has a prismatic shape, a steel pipe having a quadrangular cross section is adopted as the steel pipe, and the pillar is formed on the projecting piece formed in the rectangular frame shape. By arranging the reinforcing bars in a rectangular basket shape, a prismatic column can be accurately and easily formed on the circular pile head.

  Furthermore, according to the invention which concerns on Claim 3, the hole for reinforcing bar insertion provided in the upper side protrusion piece provided in the periphery of the said steel pipe is formed in the notch hole opened to the protrusion end surface of the protrusion piece. Therefore, when arranging the lower end of the reinforcing bar of the column around the steel pipe, the reinforcing bar can be inserted into the notch hole from the protruding end face side of the upper projecting piece, making the bar arrangement work more smoothly and efficiently. It can be carried out.

  Moreover, according to the invention which concerns on Claim 4, horizontal force by earthquake etc. acted while the insertion length with respect to the pillar and pile in the upper and lower parts of a steel pipe was made equal, and the arrangement length to a pile was applied. As the length that can sometimes resist the pulling force from the pile, the amount of deformation of the steel pipe can be increased with respect to the horizontal force acting on the connection between the pile and the column when an earthquake occurs, further reducing the bending moment. The structure can be designed.

  Next, the best mode for carrying out the present invention will be described. Connection between a reinforced concrete pile 1 in a cast-in-place concrete structure such as a viaduct and a reinforced concrete pillar 2 erected on the pile 1 As shown in FIG. 1, these piles 1 and columns 2 have a structure in which the piles 1 and the columns 2 are integrally connected by a steel pipe 3 having a certain length, and a beam 8 is provided at the lower end of the columns 2. It is a structure that is connected together.

  Although the said pile 1 and the pillar 2 may be a column shape or a prism shape, in the embodiment of the present invention, the pile 1 has a column shape as shown in FIG. The thickness is formed in a prismatic shape substantially equal to the diameter of the pile 1. The steel pipe 3 is a rectangular tube having a rectangular cross section which is thinner than the diameter of the pile 1 and the thickness of the column 2, that is, a smaller cross section than the cross section of the pile 1 and the column 2. The bottom 3b is inserted into the concrete at the center of the cross section at the center of the cross section and fixed in the embedded state, and the lower part 3b is inserted into the concrete at the center of the cross section at the top of the pile head and fixed in the embedded state. The length of the upper part 3a of the steel pipe 3 inserted into the pile 2 is equal to the length of the lower part 3b of the steel pipe 3 inserted into the pile 1, and the pile is applied to the horizontal force acting on the steel pipe 3 during an earthquake. The insertion length can exhibit a sufficient pulling resistance from 1.

  Further, in this steel pipe 3, the upper and lower ends of the steel pipe 3 embedded in the lower end portion of the column 2 are spaced at regular intervals in the vertical direction on the four sides (front and rear surfaces and both side surfaces) of the central portion 3c in the longitudinal direction. Thus, a pair of beam reinforcing projections 4 and 5 are provided around.

  These projecting pieces 4 and 5 are made of a flat rectangular steel plate material having a constant thickness projecting horizontally from the four-side outer peripheral surface of the steel pipe 3, and each upper projecting piece 4 has an upper projecting piece 4 as shown in FIG. , Holes 6 are provided at the same intervals as the reinforcing bars 2a, 2a, etc., through which the lower ends of the longitudinally long reinforcing bars 2a that are arranged in parallel in the circumferential direction (width direction) of the column 2 are arranged at regular intervals. At the same time, the lower ends of the reinforcing bars 2a passing through the holes 6 from the lower end of the column 2 and hanging downward are received in contact with the upper surface of the lower projecting piece 5. Yes.

  And the rectangular frame-shaped main reinforcement embed | buried under the four-way outer peripheral part of the concrete 2b of the pillar 2 of a rectangular cross section by these reinforcing bar rows of the front and rear sides and both sides which are arrange | positioned so that the outer peripheral surface of the steel pipe 3 may be surrounded It is composed. Further, the lower end of each reinforcing bar 2 a is formed in a fixing portion 2 c that is bent in a side U-shaped hook shape, and this fixing portion 2 c places each reinforcing bar 2 a in a corresponding hole 6 of the upper protruding piece 4. After being inserted, it is connected to the lower end of the reinforcing bar 2a by the joint member 7, and then the fixing portion 2c is received on the lower projecting piece 5. Note that the front and rear and upper and lower upper and lower protrusions 4 and 5 may be formed by a rectangular annular plate that is continuous in the circumferential direction of the steel pipe 3, and if formed in this way, the reinforcing bars 2a are also formed at the four corners. An insertion hole can be provided.

  Further, between the lower surface of the lower projecting piece 5 and the upper end surface of the pile 1, the reinforcing bar 1a on the pile 1, the reinforcing bar 2a on the column 2 side, and the beam reinforcing member 8a 'are not arranged. There is only a short length portion (hereinafter referred to as a short pipe portion 3d) of the lower end in the central portion of the steel pipe 3 embedded with concrete in which the upper end of 1 and the lower surface of the beam 8 (lower end of the column 2) are integrated. A connecting portion 9 between the pile 1 and the pillar 2 is provided. The short pipe portion 3d may be exposed without placing concrete around the short pipe portion 3d of the steel pipe 3 in the connection portion 9. Thus, the upper end portion of the reinforcing bar 1a of the pile 1 is embedded in the upper end portion of the concrete 1b of the pile 1, and the lower end of the reinforcing bar 2a of the column 2 is located above the upper end surface of the pile 1 via the connecting portion 9 above. The bar arrangements 1a and 2a are separated from each other without being connected to each other. Further, the upper and lower beam bars 8 a and 8 a ′ of the underground beam 8 are also integrally fixed to the upper and lower projecting pieces 4 and 5 of the steel pipe 3 by welding, and below the lower projecting piece 5. There are no beam bars.

  Therefore, the reinforcing bar 1a of the reinforced concrete pile 1 and the reinforcing bar 2a of the reinforced concrete column 2 are separated from each other vertically via the short pipe portion 3d (connecting portion 9) of the steel pipe 3, and cross or connect each other. In particular, the column-shaped pile 1 having the reinforcing bars 1a arranged in a circular shape and the reinforcing bars 2a arranged in a rectangular shape were difficult to connect because the bar arrangement was congested. Construction with the prism 2 having a prismatic shape can be greatly simplified and a concrete structure with high accuracy can be constructed.

  Further, the connecting portion 9 is provided between the lower surface of the underground beam 8 that integrally connects the lower ends of the columns 2 and the upper end surface of the pile 1, and the connecting portion 9 includes the pile 1. Because there is a short pipe part 3d of the steel pipe 3 connecting the steel beam 8 and the underground beam 8, when a horizontal force acts on the concrete structure at the time of the earthquake, the cross-sectional area is smaller than that of the pile 1 and the column 2 In this steel pipe 3, the pile head bending moment can be reduced by reducing the rigidity of the short pipe portion 3d on the pile head connecting the pile head and the underground beam 8. Moreover, since the reinforcing bar 1a of the pile 1 is not extended and settled to the underground beam 8, not only the pile head processing becomes easy, but also the reinforcing bar 1a of the pile 1 and the reinforcing bar 2a of the column 2 are separated. Since the bar arrangement is performed separately, the bar arrangement work of the joint portion of the pile 1, the column 2 and the underground beam 8 can be greatly improved as the amount of the bar arrangement is reduced.

  Next, the construction method of the said pile 1, the pillar 2, and the underground beam 8 is demonstrated easily. First, after excavating a circular hole (not shown) from the ground surface to a certain depth by the casing method, the reinforcing bar 11 that is the bar arrangement 1a of the pile 1 is built in this hole, and then concrete is put into the hole. The pile 1 is constructed by driving. The upper end surface of the pile 1 is located below the ground surface by a certain depth.

  Then, while the cast concrete is not hardened, a work table (not shown) is installed on the ground surface so as to straddle the open end of the cylindrical body, and the steel pipe 3 is appropriately suspended from the work table. A tool (not shown) is used to suspend the steel pipe 3 in the cylindrical body with the center of the steel pipe 3 aligned with the center line of the pile 1, and the lower part 3b of the steel pipe 3 is suspended in the center of the pile head. 3 is inserted and embedded so as to leave the length of the short pipe portion 3d from the lower projecting piece 5, and the lower portion 3b is fixed integrally with the concrete 1b by hardening the concrete as shown in FIG. The upper part 3a of the steel pipe 3 is erected vertically from the center of the upper end surface of the pile 1.

  Next, after removing the work table and the cylindrical body, a groove (not shown) for forming the underground beam 8 is excavated on the ground surface, and a plurality of beam bars 8a are formed at the bottom and the upper part in the groove. , 8a 'are horizontally arranged at small intervals in the groove width direction, and the end portions in the length direction are projected horizontally from the upper and lower ends in the central portion 3c in the length direction of the steel pipe 3. The end portions of the beam bars 8a and 8a 'are fixed to the upper and lower projecting pieces 4 and 5 by welding in a state of being juxtaposed in the circumferential direction on the upper and lower projecting pieces 4 and 5, respectively. The slot is excavated from the front and rear surfaces and both side surfaces of the steel pipe 3 in four directions around the steel pipe 3, but depending on the construction position of the column 2, the underground beam 8 is directed in three or two directions. In this case, as a matter of course, the upper and lower protrusions 4 and 5 do not exist on the front and rear surfaces or side surfaces of the steel pipe 3 facing the side where the underground beam 8 is not formed.

  In addition, the piles 1 are formed sequentially with the length interval of the above-mentioned slot holes, and therefore the upper and lower beam bars 8a, 8a 'are erected on the adjacent piles 1, 1 at both ends. The steel pipe 3 is arranged in a laid state between the upper projecting pieces 4 and 4 and the lower projecting pieces 5 and 5 facing each other. In addition, when the width | variety of the beam reinforcement row | line is wider than the horizontal width of the steel pipe 3, it fixed on the protrusion pieces 4 and 5 which adjoin the right angle with respect to the protrusion pieces 4 and 5 which receive the edge part of this beam reinforcement. The beam bars at the extreme ends of the beam bars may be placed on the beam bars in an orthogonal state. Further, hoop bars 8b are incorporated into the upper and lower beam bars 8a and 8a ′ at predetermined intervals in the length direction.

  On the other hand, a plurality of rebars 2a constituting the main reinforcement of the column 2 are lowered from the ground side so as to be along the front and rear and both side surfaces of the steel pipe 3, and the lower ends thereof are provided in the upper projecting piece 4. 6, a hook-shaped fixing portion 2 c is connected to the lower end of the fixing member 2 c by a joint member 7, and the fixing portion 2 c is brought into contact with and received by the upper surface of the lower protruding piece 5. In this way, by inserting the lower end of the reinforcing bar 2a into the plurality of holes 6 provided in the four projecting pieces 4 and 5 of the steel pipe 3 and receiving the lower end on the lower projecting piece 5, the lower side Reinforcing bars 2a arranged in parallel so as to cover the front and rear surfaces of the upper and central portions of the steel pipe 3 above the projecting piece 5 and both side surfaces are built upward, and around the steel pipe 3 A rectangular frame-shaped reinforcement is constructed so as to surround it. The reinforcing bars 2a arranged in a rectangular frame shape also incorporate hoop bars 2d at predetermined intervals in the length direction.

  Next, concrete is placed in a formwork framed in a state of surrounding the reinforcing bars 2a and the beam reinforcing bars 8a, 8a 'so that the reinforced concrete column 2 and the lower end of the column 2 are integrated. The reinforced concrete underground beam 8 is created. At this time, the lower surface of the underground beam 8 is positioned below the lower projecting piece 5 in the steel pipe 3, and the lower surface and the upper end surface of the pile 1 are integrally connected by concrete and the lower projecting piece. A connecting portion 9 is formed between the upper end of the reinforcing bar 1a on the pile 1 side and the upper end of the reinforcing bar 1a and the lower end of the reinforcing bar 2a on the column 2 side. The reinforcing bar 2a for constituting the pillar 2 is provided with a hook-shaped fixing portion 2c at the lower end thereof, so that the integration of the pillar 2 and the underground beam 8 is further strengthened by the fixing portion 2c. Is called.

  In the above embodiment, the upper projecting piece 4 in the central portion of the steel pipe 3 is provided with a circular hole vertically penetrating the projecting piece 4 as the insertion hole 6 for the reinforcing bar 2a. As shown in FIG. 4, a flat and narrow hole extending from the hole 6 to the projecting end surface of the projecting piece 4, that is, a notch hole 6 </ b> A opening in the projecting end surface of the projecting piece 4 may be used. According to such a notch hole 6A, the rebar 2a can be inserted through the notch hole 6A while being laterally moved from the projecting end face side of the projecting piece 4 through the opening without being inserted from above. The reinforcing work can be performed more smoothly, and the fixing portion 2c can be formed by bending the lower end portion of the reinforcing bar 2a into a U shape without requiring the joint member 7.

  Further, in place of such a cutout hole 6A, as shown in FIG. 5, the protruding piece 4 is formed in a shape divided into a plurality of parts in the circumferential direction, and between adjacent small protruding pieces 4a, 4a formed by this division. The rebar 2a may be arranged in the space 6B while being laterally moved from the outer side or by being inserted from the upper side. Moreover, as shown in FIG. 6, the upper and lower protrusions 4 and 5 are formed in the shape of a rectangular annular plate that is continuous in the circumferential direction, and the insertion holes 6 for the reinforcing bars 2a are inserted into the upper protrusion 4 at predetermined intervals in the circumferential direction. It may be a structure provided with.

It is a simplified front view which shows the connection structure of a pile, a pillar, and an underground beam. It is a perspective view which shows the bar arrangement state for creating a pile, a column, and an underground beam. It is a simplified front view which shows a construction state. It is a perspective view which shows another embodiment of the bar arrangement state of a column. It is a cross-sectional view which shows another embodiment. It is a perspective view at the time of forming an up-and-down protrusion piece in a rectangular annular shape.

Explanation of symbols

1 pile
1a Rebar
1b Concrete 2 pillars
2a rebar
2b Concrete 3 Steel pipe
3d Short pipe part 4, 5 Vertical protrusion 6 Rebar insertion hole 8 Underground beam 9 Connection part

Claims (5)

  A pile-column connection structure in which a reinforced concrete pile and a reinforced concrete column are connected together by a steel pipe of a certain length that is thinner than these piles and columns. With the center part in the length direction of the steel pipe arranged at the connecting part with the end face, the upper and lower parts of the steel pipe are respectively connected to the center of the cross section of the upper end of the reinforced concrete column and the center of the cross section of the lower end of the pile. And a pile characterized in that it is fixed in the concrete and embedded in the concrete, and the lower end of the reinforcing bar of the column surrounding the steel pipe and the upper end of the reinforcing bar of the pile are separated without being connected, and Column connection structure.   A lower beam reinforcement mounting protrusion is attached to the side surface of the central portion in the length direction of the steel pipe, and an upper beam reinforcement attachment protrusion is attached to the side surface above the center portion. Is provided with a hole through which the lower end of the reinforcing bar of the column surrounding the upper part of the steel pipe is inserted, and the lower end of the reinforcing bar hanging downward from the lower end of the column through this hole The connection between the pile and the column according to claim 1, wherein the connection is made to be received on one upper surface, and further, the lower surface of the lower projecting piece and the upper end surface of the reinforcing bar of the pile are separated without being connected. Construction.   The connection structure between a pile and a column according to claim 2, wherein the reinforcing bar insertion hole provided in the upper protrusion is a cutout hole opened on the protruding end face side of the protrusion.   The length of insertion and installation into the pillar and pile in the upper and lower parts of the steel pipe is equal, and the length of insertion into the pile is the length that can resist the pulling force from the pile when a horizontal force is applied due to an earthquake, etc. The pile-column connection structure according to claim 1, wherein the connection structure is a pile. The pile-column connection structure according to claim 1, wherein the pile has a cylindrical shape and the column has a prismatic shape.

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