JP5659275B2 - Column and pile connection structure - Google Patents

Description

  The present invention relates to a column-to-pile joint structure in which a column made of precast concrete (hereinafter referred to as PCa) is joined to a pile having a larger section, and in particular, a built-up column and a cast-in-place concrete pile in a reverse casting method. It is suitable for joining.

  Conventionally, as a construction method of a multi-story building with an underground floor, a construction method that constructs an underground frame from the foundation to the upper floor after excavation of all underground floors, and a main construction floor beam as a timber support work The reverse striking method that repeats excavation and construction of underground structures from the upper floor to the lower floor while being used is widely used. In the reverse casting method, the steel column and the pile are joined by inserting a steel steel column into the foundation pile before the cast concrete is hardened. And when the building is reinforced concrete (hereinafter referred to as RC), RC columns are constructed by building reinforcing bars and formwork around the structure pillars, and the structure pillars were treated as temporary structures. .

  In such RC buildings, steel materials are installed at the lower end in order to reduce the generation of useless materials by installing the structural pillar as a temporary material, and to simplify the work and shorten the construction period. For example, Patent Documents 1 and 2 propose a construction method for an underground structure using a PCa pillar. Among them, in the invention described in Patent Document 1, the steel material at the lower end is embedded in the pile concrete to ensure adhesion, and further, the reinforcing bar extended from the lower end of the PCa main body portion of the PCa column and the upper end of the cast-in-place pile is extended. The PCa pillar and the pile are joined by winding the reinforced bar with foundation concrete. On the other hand, in the invention described in Patent Document 2, in addition to the above-described joint structure, a large number of stud dowels are provided on the outer peripheral surface of the steel material at the lower end to enhance the adhesion between the steel material and the pile.

JP-A-7-82892 Japanese Patent No. 3625892

  However, when the strength of the PCa column is increased with the increase in the number of buildings, if the high-strength PCa column and the low-strength cast-in-place pile are directly joined, the conventional PCa column-pile joint structure has the PCa column. High-strength concrete is required for the foundation concrete due to the bearing pressure (tip axial force / cross-sectional area) on the lower surface of the steel. Therefore, for example, it is necessary to reduce the strength of the PCa column in the underground portion and increase the cross-sectional area of the PCa column, or to increase the strength of the foundation concrete so as to be compatible with the strength of the PCa column. However, when the cross-sectional area of the PCa column is increased, not only the material is increased, but also the lifting equipment for building the PCa column is enlarged and the construction cost is increased. On the other hand, when the strength of the foundation concrete is increased, the entire foundation is actually constructed with high-strength concrete that is necessary only at the joining portion, leading to an increase in material costs.

  The present invention has been made in view of such a background. When joining a high-strength PCa column applied to a high-rise building to a pile, the column and the pile can reduce useless material costs and suppress construction costs. It aims at providing the junction structure with.

In order to solve the above-described problems, the present invention provides a column-to-pile joint structure in which a PCa column is joined to a pile having a larger cross section than the PCa column, and a steel column member (steel formed in a closed section) Axial force transmission composed of a cylindrical member 41) and a PCa concrete portion ( 42) filled in the steel column member ( 41) and having a smaller cross section than a pile (cast-in-place pile 3) parts and (60) PCa columns having in the vicinity of the upper surface of the pile (3) (P Ca columns 5 2), which is formed just above the pile (3) will involve axial force transmitting portion (60) basic The axial force transmission part (60) includes concrete (15), and is disposed inside a reinforcing bar (reinforcing bar 19) that protrudes upward from the upper surface of the pile (3), and is larger than the PCa column directly above it. is formed in cross-section, steel post member (4 1) has an outer projection projecting from the outer surface (outer And having an inner projection projecting from the annular collision Article 4 3) and an inner surface (inner annular collision Article 4 4).

According to this invention, the axial force of the PCa column member is transmitted from the PCa concrete portion of the axial force transmission portion to the steel column member via the inner protrusion, and is transmitted from the steel column member to the foundation concrete via the outer protrusion. To do. Therefore, the axial force of the PCa column member is not only transmitted as a supporting pressure directly applied to the foundation member (foundation concrete and pile) from the downward surface of the PCa column member, but also spreads from the outer surface of the axial force transmission portion through the foundation concrete. Transmit to a wider area on the top of the pile. Therefore, the support pressure by the downward surface of the PCa column member is reduced, and even when a high-strength PCa column is used as the building becomes taller, that is, with increasing weight, the PCa column does not increase the strength of the foundation concrete. Can be directly joined to the pile, and the material cost of the foundation can be reduced. Moreover, since there is no need to increase the PCa Columns of the cross section of the underground part, it is not necessary to use a large lifting equipment can allow that you reduce the construction cost.

Further, according to this invention, it is possible to reduce the bearing capacity force generated largely to foundation concrete and piles the area of the lower surface of PCa Columns, axial force axial force in the direction pulling exerted on PCa column, such as during an earthquake In order to transmit to the pile via the foundation concrete or foundation concrete by the stepped surface corresponding to the upward surface of the transmission part, that is, the area that is larger than the PCa pillar in the axial force transmission part, the joint of the PCa pillar and the pile Seismic capacity can be increased.

Moreover, according to one aspect of the present invention, in the joint structure between the column and the pile, the steel column member (41) strikes at the same time as the portion directly above the axial force transmission portion (60) in the PCa column member (52). It is characterized by being made integral with the PCa concrete part (42) by the provided concrete .

According to one aspect of the present invention, in the joint structure between the pillar and the pile, the foundation concrete (15) includes a pressure plate (16) constructed on the upper surface of the pile (3), and the pressure plate (16). A footing concrete (17) constructed on the upper surface, and the axial force transmission part (60) is made of the foundation concrete (17) constructed by the footing concrete (17) placed on the upper surface of the pressure plate (16). 15) .

According to one aspect of the present invention, in the joint structure between the column and the pile, a reinforcing bar is inserted into the pressure plate (16), and a reinforcing bar connecting means is inserted into the PCa column member (52). The PCa column member (52) is joined to the pressure plate (16) by the means and the incision bar .

  As described above, according to the present invention, when a high-strength PCa column applied to a high-rise building is joined to a pile, a joint structure between the column and the pile that can reduce useless material cost and suppress construction cost is provided. can do.

Side view of the main part of the building according to the first embodiment II-II sectional view in FIG. III-III sectional view in FIG. IV-IV sectional view in Fig. 1 VV sectional view in FIG. Explanatory drawing of the construction procedure of the building concerning a 1st embodiment Action explanatory drawing by the junction structure of a pillar and a beam concerning a 1st embodiment Side view of main part of building according to second embodiment IX-IX sectional view in FIG. Explanatory drawing of the action by the joint structure of pillar and beam according to the second embodiment Side view of the main part of a building according to a modification of the second embodiment XII-XII sectional view in FIG. Action explanatory drawing by the junction structure of the pillar and beam concerning the modification of 2nd Embodiment Side view of main part of building according to third embodiment XV-XV sectional view in FIG. Explanatory drawing of the construction procedure of the building concerning a 3rd embodiment Explanatory drawing of the action by the joint structure of pillar and beam according to the third embodiment Explanatory drawing by the junction structure of a pillar and a beam concerning a 4th embodiment

  Hereinafter, each embodiment of the junction structure of a pillar and a pile concerning the present invention is described, referring to drawings.

<< First Embodiment >>
First, a first embodiment of the present invention will be described with reference to FIGS. Drawing 1 is a principal part side view of the building concerning an embodiment, and has broken and shown the lower half part. In each figure, in order to avoid the figure becoming complicated, some reinforcing bars and hatching are omitted. As shown in FIG. 1, the pillar-to-pile joint structure according to the first embodiment joins the PCa true pillar 2 to the cast-in-place pile 3 having a larger cross section than the PCa true pillar 2. The building 1 of the present embodiment is a multi-layered building having 2 floors below ground and 30 floors above ground, and most of the housing including the underground part is composed of PCa members (PCa pillars 20 and PCa beams 24a and 28).

  The PCa true pillar 2 is composed of an upper true pillar member 4 that forms the pillar of the first basement and a lower true pillar member 5 that forms the pillar of the second basement. As shown in FIG. 2, the upright column member 4 is an RC PCa column having a rectangular cross section and having a column main reinforcement 6 disposed in the vicinity of the outer edge. A joint portion 2a to be joined is provided. On the other hand, the lower construction column member 5 extends over the entire length along its axis, and is made of an SRC structure having a steel column 7 projecting downward from the lower end of a steel reinforced concrete (hereinafter referred to as SRC) portion 5a. PCa pillar. As shown in FIG. 5, the steel column 7 has a cross-sectional shape in which an H-shaped structure is crossed in a cross shape, and has a cross-sectional performance that can withstand the entire long-term load of the building 1. A top plate 8 is attached to the upper end of the steel column 7 (indicated by an imaginary line in FIG. 3). The outer surface of the SRC portion 5a and the outer surface of the lower portion of the steel portion 5b protruding downward are provided on the outer surface. A static gibber 9 is projected. The lower portion of the steel frame portion 5 b where the stat gibel 9 is projected protrudes into the cast-in-place pile 3.

  As shown in FIG. 3, the SRC portion 5a of the lower construction column member 5 has the same rectangular cross section as the upper construction column member 4, and the column main reinforcement 6 is disposed in the vicinity of the outer edge, and the axial center. A steel column 7 is arranged. In addition, an axial force transmission portion 10 disposed at a predetermined interval near the upper surface of the cast-in-place pile 3 is provided at the lower end of the SRC portion 5 a of the lower structure pillar member 5. As shown in FIG. 4 as well, the axial force transmission portion 10 has substantially the same cross-sectional shape as the other portions of the SRC portion 5a and has substantially the same cross-sectional area. That is, it has a rectangular cross section with a smaller cross-sectional area than the cast-in-place pile 3. The axial force transmission part 10 is disposed at the edge, and is formed of a steel square column member 11 having a closed cross section formed by four planar steel plates that are vertically erected so as to have a rectangular cross section, and a steel square column member 11 includes a PCa concrete portion 12 formed of concrete placed inside the steel column 7 in a state where the steel column 7 is disposed at the center.

  As shown in the enlarged view of FIG. 1, an outer annular ridge 13 formed in an annular shape so as to protrude outward and extend substantially horizontally is formed at an appropriate position on the outer surface of the steel square column member 11. ing. In the present embodiment, three outer annular ridges 13 are formed at the upper end, the center, and the lower end of the steel square column member 11. Further, on the inner side surface of the steel quadrangular column member 11, an inner annular ridge 14 formed in an annular shape so as to protrude inward and extend substantially horizontally is formed at an appropriate position. In the present embodiment, three inner annular ridges 14 are formed in the upper half central portion of the steel square column member 11, in the vicinity of the lower end of the steel square column member 11, and in the middle position thereof. The width and height of the outer annular ridge 13 are larger than those of the inner annular ridge 14, and both the annular protrusions 13 and 14 are joined to the steel square column member 11 by welding all around. Has been.

  The upper main column member 4 and the lower main column member 5 are connected to each other by a well-known reinforcing bar joint means 18 such as a mortar filling joint, and the grout is filled between both members. As a result, they are joined together to form a single PCa structure pillar 2 as a PCa pillar member. In addition, a foundation concrete 15 is formed on the joint portion between the PCa structural pillar 2 and the cast-in-place pile 3, that is, on the upper surface of the cast-in-place pile 3, so as to entrain the axial force transmitting portion 10. Here, the pressure plate 16 constructed on the upper surface of the cast-in-place pile 3 and the footing concrete 17 constructed on the upper surface of the pressure plate 16 are collectively referred to as foundation concrete 15. In addition, a base beam 22 that supports the second basement slab 21 is joined to a portion of the lower structure column member 5 where the foundation concrete 15 is constructed, and a joint portion provided at the lower end of the upper structure column member 4. 2a is joined with a basement first floor beam 24 that supports a basement first floor slab 23, and a first floor slab 26 is formed at the lower end of an RC pillar 25 constructed of cast-in-place concrete above the upper column member 4. The supporting first floor beam 27 is joined.

  Next, the construction procedure of the building 1 having such a joint structure will be described with reference to FIG. First, as shown to (A), the pile hole 29 according to the cross section and the depth of the cast-in-place pile 3 is drilled in the ground G using the excavator which is not shown in figure. Next, as shown in (B), after inserting the reinforcing bar 19 into the pile hole 29 and placing the concrete in the pile hole 29, the PCa frame column 2 is inserted into the pile hole while the concrete is uncured. The cast-in-place pile 3 is constructed by curing the concrete in a state where the PCa frame pillar 2 is fixed at a predetermined height position where the lower portion of the steel column 7 is embedded in the concrete. In addition, the PCa structural pillar 2 is made into a single piece by previously joining the upper structural pillar member 4 and the lower structural pillar member 5 on the ground. Alternatively, the cast-in-place pile 3 may be constructed by placing concrete in the pile hole 29 in a state where the PCa frame column 2 is first built in the pile hole 29 and fixed at a predetermined position.

  Subsequently, as shown in (C), the ground G is excavated to a predetermined depth by the primary root cutting operation, and the first floor column 25, the first floor beam 27, and the first floor slab 26 are constructed. Thereafter, as shown in (D), the ground G is excavated to a predetermined depth by secondary root cutting work, and the underground first floor beam 24 and the underground first floor slab 23 are constructed. In parallel with this, we will also build a ground structure. Note that a PCa beam 24a is used for the first-floor beam 24 in the basement, and is joined to the lower end of the upright columnar member 4 through the concrete of the joint portion 24b which is hit in the field. In addition, a PCa column 20 having a predetermined length and a PCa beam 28 having a predetermined length are used for the frame of the ground portion. The PCa beam 28 is directly joined to the PCa column 20 by the same known joining method as described above, that is, the joining of the reinforcing bars by the known reinforcing bar joint means 18 and the grouting into the gap between the members.

  Further, as shown in (E), the ground G is further excavated by the tertiary root cutting operation to expose the pile head of the cast-in-place pile 3, and the pile head processing for hanging the pile head over a predetermined length is performed. Moreover, while constructing | assembling the pressure-resistant plate 16 on the upper surface of the cast-in-place pile 3 from which the extra part was removed, the foundation beam 22 is built and the adjacent cast-in-place pile 3 is connected. By adopting the PCa members (PCa column 20 and PCa beam 28), the building construction speed of the ground part is fast, and at this time, even if the building of the building up to the 30th floor is completed, the steel column 7 is attached to the entire building 1. Since it has a cross-sectional performance that can withstand a long-term load, the steel column 7 can be used as a permanent installation. Further, a large supporting pressure is generated at the lower end portion of the upper structure column member 4 due to the upper surface of the steel column 7, but the tensile force by the underground first floor beam 24 joined in the vicinity of the lower end portion of the upper structure column member 4. Acts, so that part will not be destroyed.

  Thereafter, as shown in (F), a footing concrete 17 having the same size as the cast-in-place pile 3 or slightly larger than the cast-in-place pile 3 is constructed on the upper surface of the pressure-resistant plate 16, and the axial force transmission unit 10 is constructed with the foundation concrete 15. In addition, the second-floor slab 21 is constructed, and the joining of the PCa structural pillar 2 and the cast-in-place pile 3 is completed.

  According to such a joint structure between the PCa frame true pillar 2 and the cast-in-place pile 3, the axial force F of the PCa frame true pillar 2 is transmitted through the inner annular ridge 14 as shown in FIG. It transmits from the PCa concrete part 12 of the part 10 to the steel square column member 11, and transmits from the steel square column member 11 to the foundation concrete 15 via the outer annular ridge 13. Therefore, the axial force F of the PCa frame column 2 is not limited to the support force F1 by the steel column 7 or the support force F2 by the downward surface of the SRC part 5a of the PCa frame column 2, but also through the foundation concrete 15 3 is also supported by the supporting force F3 by the outer surface of the axial force transmitting portion 10 supported by the entire upper surface of 3. Therefore, even if the support pressure by the downward surface of the SRC portion 5a of the PCa structural column 2 is reduced and the strength of the PCa structural column 2 is increased as the building 1 becomes taller, that is, the weight increases, The PCa structural pillar 2 can be directly joined to the cast-in-place pile 3 without increasing the concrete strength of the concrete 15 and the cast-in-place pile 3, and the material cost of the foundation concrete 15 and the cast-in-place pile 3 can be reduced. Moreover, since it is not necessary to enlarge the cross section of the PCa frame true pillar 2, the PCa frame true pillar 2 can be built in the pile hole 29 without using a large lifting equipment, and the construction cost can be reduced. . Alternatively, since the PCa frame pillar 2 can be lengthened, it is possible to construct a deeper underground structure even by the reverse driving method.

  The plurality of outer annular ridges 13 and inner annular ridges 14 are formed in an annular shape extending substantially horizontally and function as shear connectors, so that the basic concrete 15 and the PCa concrete portion 12 are directly joined with a shear key. Compared with the case where the engagement area to the outer annular ridge 13 of the foundation concrete 15 and the engagement area to the inner annular ridge 14 of the PCa concrete portion 12 are increased, the shear fracture of the engagement portion is suppressed, A larger support force F3 is exhibited by the outer surface of the axial force transmission unit 10. Therefore, the concrete strength of the foundation concrete 15 and the cast-in-place pile 3 can be made lower than the concrete strength corresponding to the supporting force F2 by the downward surface of the SRC portion 5a. In other words, the building 1 can be made higher than the case where concrete having the same strength is used for the foundation concrete 15 and the cast-in-place pile 3.

  In addition, the PCa frame column 2 including the steel column 7 projecting downward is partially inserted into the cast-in-place pile 3 in a state where the concrete is uncured, and the steel column 7 and the cast-in-place pile 3 are Axial force is transmitted by the attachment (supporting force F1 is exhibited), so that the axial force (supporting force F2) transmitted from the lower surface of the SRC portion 5a is reduced and the supporting pressure is reduced. The strength can be further reduced. Alternatively, the building 1 can be made higher as described above.

  Furthermore, because the steel column 7 extends over the entire length of the lower column member 5, the adhesion force of the steel column 7 to the concrete of the SRC portion 5a is increased, and the supporting force by the upper end surface of the steel column 7 is reduced. It is possible to suppress the destruction of the portion directly above the steel column 7 in the PCa structural column 2, that is, the lower end portion of the upper structural column member 4, and the joint portion 2 a is disposed at the lower end of the upper structural column member 4. As a result, the tensile force caused by the first-floor first-floor beam 24 acts on the portion that is easily broken by the support pressure, so that the upper surface of the steel column 7 can be prevented from being damaged by the support pressure.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the member and site | part same as 1st Embodiment, and the description which overlaps with 1st Embodiment is abbreviate | omitted. The same applies to the following embodiments.

  The difference from the first embodiment of the column-pile joint structure according to this embodiment is the steel column 37 and the axial force transmission unit 40, which will be mainly described. As shown in FIG. 8, in this embodiment, the steel column 37 is arranged only in the lower half of the lower true column member 35. That is, the lower true column member 35 includes an RC portion 35a in which the column main reinforcement 6 is disposed in the vicinity of the outer edge, and a steel frame portion 35b that is joined to the lower surface of the RC portion 35a and protrudes downward. And the RC part 35a of the lower construction pillar member 35 exhibits the same cross-sectional shape as the upper construction pillar member 4 shown in FIG.

  On the other hand, the axial force transmission part 40 which has a larger cross-sectional area than 1st Embodiment is formed in the lower end of RC part 35a of the lower structure pillar member 35. As shown in FIG. The axial force transmission part 40 arrange | positions the steel cylindrical member 41 further formed in the cylinder shape around the axial force transmission part 10 similar to 1st Embodiment so that FIG. PCa concrete is filled between the square pillar member 11 and the steel cylindrical member 41. In other words, the steel column member 41 is formed of a curved steel plate that is disposed on the outer edge of the axial force transmission unit 40 and is erected vertically so as to have a circular closed cross section. The steel column member 41 has a smaller diameter than the cast-in-place pile 3 so that it can be built into the pile hole 29. And the concrete arrange | positioned inside the steel cylindrical member 41, the steel square column member 11, etc. comprise the PCa concrete part 42. FIG.

  As shown in the enlarged view of FIG. 8, on the outer surface of the steel cylindrical member 41, an outer annular protrusion 43 formed in an annular shape so as to protrude outward and extend substantially horizontally is formed in a proper position. Yes. Further, on the inner side surface of the steel cylindrical member 41, an inner annular protrusion 44 formed in an annular shape so as to protrude inward and extend substantially horizontally is formed in a proper position. Also in this embodiment, the width and height of the outer annular ridge 43 are made larger than those of the inner annular ridge 44, and the outer annular ridge 43 is formed at the upper end, the center and the lower end of the steel cylindrical member 41. Three inner annular ridges 44 are formed at the upper half central portion of the steel square column member 11, near the lower end of the steel square column member 11, and at an intermediate position therebetween.

  On the other hand, an outer annular ridge 13 and an inner annular ridge 14 are also formed on the steel square column member 11 arranged along the edge of the lower true column member 35. 14 has the same width and height as the inner annular ridge 44, and is arranged in three rows at the same height position as the inner annular ridge 44.

  Since the construction procedure of the building 1 is the same as that of the first embodiment, the description thereof is omitted. The axial force transmission unit 40 having a large cross section is integrally formed with the lower main column member 35 in advance by factory manufacture, and the upper main column member 34 and the lower main column member 35 are joined in advance on the ground. It is inserted into the pile hole 29 in a state where it is a single PCa construction true pillar 32.

  According to the joint structure of the PCa true column 32 and the cast-in-place pile 3 configured as described above, the following operational effects are exhibited in addition to the operational effects of the first embodiment. That is, as shown in FIG. 10, the axial force transmission portion 40 is formed in a portion directly above, that is, with a larger cross section than the other part of the PCa true column 32, and thus the area of the downward surface of the PCa true column 32. Can be increased to increase the supporting force F2 by the downward surface, and the bearing pressure generated in the foundation concrete 15 and the cast-in-place pile 3 can be reduced. Further, the axial force in the pulling direction applied to the PCa structural column 32 during an earthquake or the like corresponds to the upward surface of the axial force transmission unit 40, that is, the area of the axial force transmission unit 40 having a larger cross section than the PCa structural column 32. Since the stepped surface 40a transmits the foundation concrete 15 or the foundation concrete 15 to the cast-in-place pile 3, the seismic resistance of the joint portion between the PCa structural column 32 and the cast-in-place pile 3 can be increased.

  Further, since a large supporting pressure is generated in the portion directly above the steel column 37 in the PCa frame true column 32, the portion is easy to break, but the upper end of the steel column 37 is positioned at the lower end of the axial force transmission unit 40. This easily breakable portion is the axial force transmission unit 40. The axial force transmission unit 40 is wound around the foundation concrete 15 and the steel column member 41 is disposed on the outer edge so as to surround the PCa concrete unit 42. It is possible to prevent the damage due to the support pressure on the upper surface. Further, the axial force transmitting portion 40 is provided with the steel square column member 11 not only on the outer edge steel column member 41 but also on the inside along the outer surface of the PCa column true column 32. The axial force F of the true pillar 32 is reliably transmitted to the entire area of the lower surface of the axial force transmission unit 40. Further, since the steel column 37 does not enter the RC portion 35a of the lower true column member 35, the axial force that transmits the steel column 37 is concentrated on the upper surface (top plate 8) of the steel column 37. 11 is formed in a closed cross section, it also functions to increase the proof strength against the support pressure of the steel column 37 and prevent the axial force transmission unit 40 from being broken.

<< Modification of Second Embodiment >>
Next, a modification of the second embodiment of the present invention will be described with reference to FIGS.

  The difference between the column and pile connection structure according to this modification example and the second embodiment is the configuration of the axial force transmission unit 40. As shown in FIGS. 11 and 12, the axial force transmission portion 40 ′ of the present modification has an outer surface shape similar to that of the second embodiment, and is along the outer surface of the RC portion 35 a of the lower structure pillar member 35. Instead of the steel square column member 11, a steel small-diameter columnar member 11 ′ formed smaller than the outer surface of the RC portion 35a of the lower true column member 35 is provided therein. The steel small-diameter columnar member 11 ′ has a size that can be arranged inside the column main reinforcement 6 arranged inside the lower true column member 35, and is almost the same size as the upper surface (top plate 8) of the steel column 37. Formed. In addition, the point by which the steel cylindrical member 41 is arrange | positioned at the outer edge of axial force transmission part 40 'is the same as that of 2nd Embodiment, and the PC concrete and steel small diameter arrange | positioned inside the steel cylindrical member 41 are included. The cylindrical member 11 ′ constitutes the PCa concrete portion 42 ′. As shown in the enlarged view of FIG. 11, the steel small-diameter columnar member 11 ′ disposed inside the lower true column member 35 is also provided with the outer annular ridge 13 ′ and the inner annular ridge, as in the second embodiment. Article 14 'is formed

  The construction procedure of the building 1 is the same as in the first and second embodiments. The concrete inside and outside the steel small-diameter columnar member 11 ′ is placed at the same time as the lower true column member 35 is manufactured at the factory.

  According to the joining structure of the PCa structural pillar 32 and the cast-in-place pile 3 configured as described above, the same effects as those of the second embodiment are exhibited. That is, as shown in FIG. 13, the axial force transmission portion 40 ′ is formed in a larger cross section than the upper part thereof, so that the supporting force F <b> 2 due to the downward surface of the PCa frame column 32 is increased, and the foundation concrete 15 and the place The supporting pressure generated in the pile 3 is reduced. Further, since the axial force transmission portion 40 ′ is provided with the upward step surface 40 a ′, the earthquake resistance of the joint portion between the PCa structural pillar 32 and the cast-in-place pile 3 is increased. Further, the steel columnar member 41 is disposed so as to surround the PCa concrete portion 42 ′, and the axial force transmission portion 40 ′ is caught in the foundation concrete 15, thereby preventing breakage due to the support pressure on the upper surface of the steel column 37. .

  Further, in the axial force transmission portion 40 ′, not only the outer steel column member 41 but also the inside of the PCa structural column 32, the steel small-diameter column member 11 ′ having the same size as the upper surface of the steel column 37 is provided. Therefore, the damage caused by the support pressure on the upper surface of the steel column 37 is effectively prevented, and the axial force F of the PCa construction true column 32 is reliably transmitted to the entire area of the lower surface of the axial force transmitting portion 40. Is done.

«Third embodiment»
Next, a third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the building 1 is constructed not by the reverse driving method using the structural pillar but by the forward driving method. In addition, although this embodiment demonstrates as the building 1 of the underground 2 floor 30 floors similarly to the said embodiment, the multilayer building which does not have an underground part may be sufficient.

  As shown in FIG. 14, the column / pile joint structure according to the present embodiment joins the PCa column member 52 to the cast-in-place pile 3 having a larger cross section than the PCa column member 52. In the building 1 of this embodiment, PCa members are used for all columns and beams. The pressure plate 16 is constructed on the upper surface of the cast-in-place pile 3, and the PCa column member 52 is placed on the upper surface of the pressure plate 16. Above the PCa column member 52, the second basement column 55 and the first basement column 54 are sequentially joined. Above the first basement column 54, the PCa column 20 on the ground floor is joined sequentially. These underground second-floor pillar 55, underground first-floor pillar 54, and PCa pillar 20 have a rectangular cross-sectional shape in which the column main reinforcement 6 is disposed in the vicinity of the outer edge, similarly to the upper true pillar member 4 shown in FIG.

  Similarly, the PCa column member 52 is an RC PCa column having the same cross-sectional shape as the upper true column member 4 shown in FIG. 2, and the axial force transmission portion 60 whose cross section is shown in FIG. I have. In addition, the axial force transmission part 60 of this embodiment is the 2nd shown in FIG. 9 except the point by which the steel column 37 is not joined to the lower surface, and the point which does not have the steel square pillar member 11 (axial force transmission part 10). The axial force transmission unit 40 of the embodiment has the same configuration and the same shape. That is, the axial force transmission part 60 arrange | positions the steel cylindrical member 41 formed in the cylinder shape around the PCa pillar member 52, and filled PCa concrete between the PCa pillar member 52 and the steel cylindrical member 41. The PC concrete which comprises a structure and is arrange | positioned inside the steel cylindrical member 41 comprises the PCa concrete part 42. FIG. The steel column member 41 and the PCa column member 52 are integrally formed by simultaneously placing concrete. And the outer side annular protrusion 43 arrange | positioned in the up-down direction at 3 rows is formed in the outer side surface of the steel cylindrical member 41, and the inner side arrange | positioned in the up-down direction at the inner side surface of the steel column member 41 An annular ridge 44 is appropriately formed. The PCa column member 52 is joined to the cast-in-place pile 3 by constructing the footing concrete 17 with the axial force transmission portion 60 in contact with the upper surface of the pressure plate 16 and winding it with the foundation concrete 15.

  Next, the construction procedure of the building 1 of this embodiment will be described with reference to FIG. First, as shown to (A), after drilling the pile hole 29 according to the cross section and depth of the cast-in-place pile 3 in the ground G using the excavator which is not illustrated, the reinforcing bar 19 is put in the pile hole 29. While inserting, the cast-in-place pile 3 is constructed by placing concrete in the pile hole 29. Next, as shown in (B), the ground G is excavated to a depth at which the pile head of the cast-in-place pile 3 is exposed by root cutting using a soil retaining member (not shown), and the pile head of the surplus portion is piled up. The pressure plate 16 is constructed on the upper surface of the cast-in-place pile 3 from which the PC is removed, and the PCa column member 52 is placed on the upper surface. In addition, the PCa column member 52 inserts a reinforcing bar joining means if necessary, and joins it to the reinforcing bar inserted into the pressure plate 16 and the cast-in-place pile 3. Thereafter, as shown in (C), the foundation beam 22 is constructed and the adjacent cast-in-place piles 3 are connected to each other, and the upper surface of the pressure plate 16 has a size equivalent to the cast-in-place pile 3 or the cast-in-place pile 3. In addition, a slightly larger footing concrete 17 is constructed and the axial force transmission part 60 is wound up with the basic concrete 15, and the second-floor slab 21 is constructed, and the joining of the PCa column member 52 and the cast-in-place pile 3 is completed.

  Subsequently, as shown in (D), the second basement column 55 is joined to the upper surface of the PCa pillar member 52, and the first basement column 54 is joined to the upper surface, and provided at the lower end of the first basement column 54. The basement first-floor beam 24 is joined to the formed joint, and the basement first-floor slab 23 is constructed. Furthermore, as shown in (E), the first floor column 20 is joined to the upper surface of the first basement column 54, the first floor beam 27 is joined to the lower end of the first floor column 20, and the first floor slab 26 is constructed. Build a ground floor enclosure.

  According to such a joint structure of the PCa column member 52 and the cast-in-place pile 3, as shown in FIG. 17, the axial force of the PCa column member 52 is the same as described in the first embodiment and the second embodiment. F is transmitted to the steel cylindrical member 41 via the inner annular ridge 44 and from the steel cylindrical member 41 to the foundation concrete 15 via the outer annular ridge 13. Therefore, the axial force F of the PCa column member 52 is transmitted not only as the supporting force F2 due to the downward surface of the axial force transmitting portion 60 but also through the foundation concrete 15, and is supported by the entire upper surface of the cast-in-place pile 3. Also, the supporting force F3 by the outer surface of the axial force transmitting portion 60 is transmitted to the foundation concrete 15 and the cast-in-place pile 3. Therefore, the supporting pressure generated in the foundation concrete 15 and the cast-in-place pile 3 directly below the PCa column member 52 can be reduced. Moreover, it is the same as that of 2nd Embodiment that the earthquake strength of the junction part of the PCa pillar member 52 and the cast-in-place pile 3 increases with the upward level | step difference surface 60a of the axial force transmission part 60. FIG.

  As described above, even when the joining structure according to the present invention is applied not only to the reverse driving method but also to the forward driving method, the PCa column member 52 having a relatively high strength and a small cross section has a relatively low strength and a large cross section. It becomes possible to join directly to the foundation concrete 15 and the cast-in-place pile 3. That is, the concrete strength of the foundation concrete 15 and the cast-in-place pile 3 is increased to an extent suitable for the strength of the PCa column member 52, or the concrete strength of the PCa column 20 on the ground is changed to the first basement column 54 and the second basement column 55. There is no need to reduce the concrete strength step by step to make a large section.

<< Fourth Embodiment >>
Finally, a fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, a building 1 is constructed by a striking method using a PCa column member 72 having an axial force transmission portion 80 having an outer shape similar to that of the axial force transmission portion 10 of the first embodiment at the lower end. . The axial force transmission unit 80 has the same configuration and the same shape as the axial force transmission unit 10 of the first embodiment except that the steel column 7 is not provided at the center thereof. Since the configuration of other members and the construction method of the building 1 are the same as those in the third embodiment, description thereof is omitted. Also by the joining structure of the PCa pillar member 72 and the cast-in-place pile 3 having such a configuration, the same effect as described in the first embodiment and the third embodiment can be obtained.

  This is the end of the description of specific embodiments, but the present invention is not limited to these embodiments. For example, in the second embodiment and the third embodiment, the upward stepped surfaces 40a and 60a are formed in a horizontal plane. However, in order to transmit the axial force F reliably by the axial force transmitting portions 40 and 60, the PCa structure The portions directly above the axial force transmission portions 40, 60 of the true column 32 and the PCa column member 52 may be tapered so as to expand in a divergent shape, and the upward stepped surfaces 40a, 60a may be formed in a trapezoidal conical shape. In addition, the specific shape, arrangement, quantity, and the like of each member and part are not limited to those shown in the above embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

2,32 PCa structural column (PCa column member)
52,72 PCa column member 2a Joint part 3 Cast-in-place pile (pile)
7, 37 Steel column 10, 40, 40 ', 60, 80 Axial force transmission part 11 Steel square column member (steel column member)
11 'Steel small diameter cylindrical member 41 Steel cylindrical member (steel column member)
12, 42 PCa concrete part 13, 43 Outer annular protrusion (outer protrusion)
14,44 Inner ring ridge (inner projection)
15 foundation concrete 16 pressure plate 17 footing concrete 24 underground 1st floor beam (beam)

Claims (4)

It is a joining structure of a pillar and a pile that joins a PCa pillar to a pile having a larger cross section than the PCa pillar,
A steel column member formed in a closed cross-section and a PCa concrete portion filled in the steel column member , and having an axial force transmission portion formed in a smaller cross-section than the pile at the lower end; and and PCa columns having above the upper surface of the pile the axial force transmitting portion,
A foundation concrete formed immediately above the pile so as to involve the axial force transmission part;
The axial force transmission portion is disposed inside the reinforcing bar protruding upward from the upper surface of the pile, and is formed in a larger cross section than the PCa column immediately above the reinforcing bar.
The steel column member has an outer protrusion protruding from an outer surface and an inner protrusion protruding from an inner surface, and the column / pile joint structure.   2. The steel column member according to claim 1, wherein the steel column member is integrated with the PCa concrete portion by concrete placed simultaneously with a portion immediately above the axial force transmission portion of the PCa column member. Joint structure of pillar and pile. The foundation concrete has a pressure plate constructed on the top surface of the pile, and a footing concrete constructed on the top surface of the pressure plate,
The said axial force transmission part is wound in the said foundation concrete by the said footing concrete constructed in the state mounted in the upper surface of the said pressure-resistant plate, The Claim 1 or Claim 2 characterized by the above-mentioned. Joint structure of pillar and pile. A reinforcing bar is inserted into the pressure-resistant plate, a reinforcing bar joining means is inserted into the PCa column member, and the PCa column member is joined to the pressure-resistant plate by the reinforcing bar joining means and the reinforcing bar. The joint structure of a pillar and a pile according to claim 3.

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