JP4966825B2 - Joint structure of precast concrete columns - Google Patents

Description

  The present invention relates to a joining structure for joining a precast concrete column with ultra-high strength to a column support structure having a strength lower than that of the precast concrete column.

  Conventionally, the joint portion of a precast concrete column is generally filled with a grout material having a strength stronger than that of the precast concrete column itself. However, recent advances in concrete technology have realized precast concrete columns with ultra-high-strength concrete, which is stronger than grout materials with high fluidity.

  Due to the advancement of such technology, there is a case where a reinforced concrete building is currently constructed in a joining form as shown in FIG. As shown in FIG. 8, when a grout material 102 having a lower strength than these members is filled between columns 100 and beams 101, which are ultra-high strength precast members having the same strength, the shape as shown in FIG. It has been proposed to evaluate the strength of the joint with the concrete specimen 103 (see Patent Document 1). The concrete specimen 103 is formed by filling a grout material 103b having a lower strength than these members between ultra-high strength precast members 103a and 103a having the same strength.

By the way, there exist some which are shown in patent document 2 as a joining structure of the precast concrete pillar of plain concrete which is not ultra-high strength. In this joining structure, a recess is provided in the lower end surface of the vertical member (precast concrete column), and a recess portion in which the lower end portion of the vertical member can be fitted is provided in the upper end surface of the horizontal member (column support structure). A vertical member is erected so that the lower end portion is fitted into the portion, and a grout material is injected and filled into the recessed portion and the recessed portion.
JP 2007-46416 A Japanese Patent Laid-Open No. 5-230877

  Since the joint structure as shown in FIG. 8 is common on the upper floors of buildings using ultra-high-strength precast concrete columns, the evaluation method of Patent Document 1 can be applied. However, as shown in FIG. 10, when there is a column support structure such as a floor slab 104 having a cross section significantly larger than that of the column 100 in the column base portion of the first floor, the column support structure. It is not necessary to design the (floor slab 104) with the same strength as the pillar 100, and the strength can be lowered. With such a joint structure, the evaluation method of Patent Document 1 cannot be applied, and at present, the strength of the joint cannot be evaluated with a simple calculation.

  Moreover, since the joint structure of Patent Document 2 is a joint structure of precast concrete columns of ordinary concrete, and not a joint structure of precast concrete columns of ultra-high strength concrete, the strength of the grout material as a filler is a vertical member. It is higher than the strength of the (precast concrete column) and the horizontal member (column support structure). Therefore, the grout material cannot be regarded as a part of the column, and the strength of the joint cannot be evaluated by simple calculation.

  Therefore, the present invention has been devised to solve the above-described problems, and an object thereof is to provide a precast concrete column joint structure capable of evaluating the strength of the joint by simple calculation.

  In order to solve the above-mentioned problem, the invention according to claim 1 is formed on an upper surface of the column support structure in a joining structure in which a precast concrete column is joined to a column support structure having a strength lower than that of the precast concrete column. A filler having a strength greater than that of the column support structure and less than that of the precast concrete column, between the bottom surface of the recessed portion and the precast concrete column disposed above the recess by a predetermined interval. It is the joint structure of the precast concrete pillar characterized by having filled and formed the junction part.

Here, the precast concrete column is an ultra-high-strength precast concrete column made of ultra-high-strength concrete having a concrete design standard strength of 150 N / mm ² or more, and the column support structure has higher strength than ordinary concrete. Suppose you are. The column support structure refers to a structure that supports columns such as beams, floor slabs, and foundations arranged at the lower part of the column.

  According to such a configuration, the filler is filled inside the column support structure and has a strength that is greater than the strength of the column support structure and less than the strength of the precast concrete column. It can be considered part of the column support structure, not part. Therefore, the strength of the joint can be evaluated by a general simple calculation.

  The invention according to claim 2 is the precast concrete column according to claim 1, wherein a bottom surface of the precast concrete column is inserted into the recess and located below the upper end surface of the column support structure. This is a joining structure.

  According to such a configuration, since the filler is in contact with not only the bottom surface of the precast concrete column but also the side surface, the joint strength in the shear direction between the precast concrete column and the column support structure can be further increased.

  According to the present invention, it is possible to evaluate the strength of the joint portion between the precast concrete column and the column support structure with a simple calculation.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a first embodiment of a precast concrete column joining structure according to the present invention. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a sectional view showing a construction procedure of the first embodiment of the precast concrete column joint structure according to the present invention.

  As shown in FIG. 1, the precast concrete column joining structure according to the first embodiment is a structure in which the precast concrete column 10 is joined to a column support structure 30 having a strength lower than that of the precast concrete column 10. Precast concrete having a strength higher than that of the column support structure 30 between the bottom surface 31a of the recess 31 formed on the upper surface of the column support structure 30 and the precast concrete column 10 disposed above the recess 31 with a predetermined interval. The bonding portion is formed by filling a filler 50 having a strength less than that of the pillar 10.

In the present embodiment, the precast concrete column 10 is an ultrahigh strength precast concrete column formed of ultrahigh strength concrete having a concrete design standard strength of, for example, 150 N / mm ² . The column support structure 30 is made of high-strength concrete having a higher strength (for example, 100 N / mm ² ) than ordinary concrete. The column support structure 30 is configured by a structure that supports columns such as beams, floor slabs, and foundations arranged at the lower part of the column.

  As shown in FIGS. 1 and 2, the precast concrete column 10 has a square cross section, and in the vicinity of the four corners of the lower end portion thereof, the lower end portion of the main reinforcement 11 inside the precast concrete column 10 and the column support structure 30. The coupler 12 into which the upper end portion of the anchor bar 32 extending upward from the upper and lower sides is inserted from above and below is incorporated. The main reinforcement 11 and the anchor reinforcement 32 are different diameter reinforcing bars. The coupler 12 is a member constituting a mechanical joint of a reinforcing bar by inserting a reinforcing bar into the inside and filling the filler, and an unevenness (not shown) corresponding to the unevenness of the different diameter reinforcing bar is formed inside. ing. In this embodiment, the coupler 12 has a cylindrical shape and is arranged in the vertical direction. The coupler has the largest diameter in the longitudinal direction (height direction) and gradually contracts from the large diameter portion toward the upper and lower ends. The shape is a diameter. The lower end portion of the coupler 12 is opened at the lower end portion of the precast concrete column 10 and serves as an insertion opening for the anchor bar 32. A communication hole 13 connected to the side surface of the precast concrete column 10 is formed on the side surface of the coupler 12. The communication holes 13 are formed to supply the filler 50 into the coupler 12, and some of the communication holes 13 inject the filler 50 into the lower part of the precast concrete column 10 via the coupler 12. The communication hole 13 and the internal space of the coupler 12 constitute a filler injection flow path 14. The communication holes 13 are formed at two locations with a predetermined interval in the vertical direction.

  The recess 31 formed on the upper surface of the column support structure 30 has a cross-sectional shape that is a square larger than the cross-section of the precast concrete column 10 and preferably has a predetermined depth required to join the precast concrete column 10, preferably Has a depth of 10 mm or more. The outer peripheral surface of the recessed part 31 is formed in the position extended from the outer peripheral surface of the precast concrete pillar 10 to the outer side of the length equivalent to a depth dimension. In addition, the spacer 20 is disposed substantially at the center of the bottom surface 31 a of the recess 31.

  The spacer 20 is for arranging the precast concrete pillars 10 on the bottom surface 31 a of the recess 31 with a predetermined interval. The spacer 20 is formed of a material such as hard resin or concrete, and is configured to withstand the load of the precast concrete column 10 placed on the upper part during construction. The spacer 20 has a height dimension equivalent to the depth dimension of the recess 31, and the lower end portion of the precast concrete column 10 is arranged at a height equivalent to the upper surface of the column support structure 30. Yes. The spacer 20 is formed in a truncated cone shape whose upper side has a small diameter, and the angle of the protruding corner portion of the upper end peripheral edge portion becomes an obtuse angle.

The filler 50 is composed of grout mortar. This grout mortar can exhibit strength (for example, 130 N / mm ² ) that is higher than the strength of the column support structure 30 and less than the strength of the precast concrete column 10, and can flow through the filler injection flow channel 14. What is provided with is used.

  Next, the construction procedure of the precast concrete column joining structure having the above-described configuration will be described with reference to FIG.

  First, as shown in FIG. 3 (a), after reinforcing bars are placed in a mold (not shown), high-strength concrete is placed in the mold, and a column support structure having a recess 31 on the upper surface. 30 is formed. Here, the anchor bars 32 are arranged so as to protrude upward from the bottom surfaces 31 a at the four corners of the recess 31.

  Next, as shown in FIG. 3 (b), after the spacer 20 is installed in the substantially central portion of the recess 31 of the column support structure 30, the precast concrete previously formed with ultrahigh strength concrete at a factory or the like. The pillar 10 is built from above the recess 31 and placed on the spacer 20. At this time, the upper part of the anchor bar 32 is inserted into the coupler 12 from the bottom of the precast concrete column 10. At this time, the installation height of the precast concrete pillar 10 can be easily guided by providing the spacer 20.

  Then, adjustment of erection accuracy, such as angle correction of the precast concrete pillar 10, is performed. At this time, since the spacer 20 is formed in the shape of a truncated cone, the angle of the protruding corner of the peripheral edge at the upper end is obtuse, so that the precast concrete column 10 can be easily tilted and the angle can be easily corrected. In addition, breakage of the protruding corner portion of the spacer 20 hardly occurs.

  After completion of the adjustment of the precast concrete column 10 erection accuracy, as shown in FIG. 3C, a plate-like filler overflow prevention plate 21 that covers the periphery of the recess 31 around the precast concrete column 10. Is installed. Thereafter, the filler 50 is injected from one portion of the lower communication hole 13 that opens to the side surface of the precast concrete column 10, passes through the filler injection channel 14, and fills the recess 31. At this time, since the filler 50 has appropriate fluidity, it can smoothly pass through the filler injection channel 14. After the recess 31 is filled with the filler 50, the filler 50 is supplied until the inside of the filler injection channel 14 is filled. At this time, since the filler overflow prevention plate 21 is provided, the filler 50 does not overflow the surface of the column support structure 30. Further, since the filler 50 overflows from the through holes 13 other than the through hole 13 used for the injection of the filler 50, it can be confirmed that the filler 50 is filled up to the height of the through hole 13. Thereafter, when the filler 50 is hardened by curing for a predetermined time, the filler overflow prevention plate 21 is removed, and the construction of the joining structure is completed.

  According to the joint structure of the precast concrete columns 10 constructed as described above, the filler 50 having a strength higher than the strength of the column support structure 30 and less than the strength of the precast concrete column 10 is used. By filling the recess 31 formed in the plane of 30, the filler 50 can be regarded as a part of the column support structure 30, not a part of the precast concrete pillar 10. Therefore, in such a joint structure, the structural calculation can be performed on the assumption that the precast concrete column 10 is simply joined to the column support structure 30. Therefore, the strength of the joint can be evaluated by a general and simple known calculation.

  Further, by providing the spacer 20 on the bottom surface 31a of the recess 31, the position in the height direction of the precast concrete column 10 can be easily determined. Furthermore, since the spacer 20 has a truncated cone shape, the installation angle of the precast concrete column 10 can be easily adjusted, and the precast concrete column 10 can be easily tilted on the spacer 20 so that the installation angle can be adjusted more easily. become.

  FIG. 4 is a cross-sectional view showing a second embodiment of the precast concrete column joining structure according to the present invention.

  In the joint structure of the precast concrete columns according to the first embodiment, the filler 50 is filled in the whole of the recess 31 and the filler injection flow path 14, whereas the joint of the precast concrete columns according to the second embodiment. As shown in FIG. 4, the structure is characterized in that a joint filler 51 is filled in the filler injection flow path 14 of the precast concrete column 10. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given and description thereof is omitted.

  The joint filler 51 is filled in the filler injection channel 14 after filling the recess 31 with the filler 50 via the filler injection channel 14. The joint filler 51 is made of, for example, an inflatable filler. When the joint filler 51 is cured in the coupler 12, the expansion force is increased on the entire surface of the main reinforcement 11, the anchor reinforcement 32, and the coupler 12. The joint portion can be brought into a completely rigid joint state. Thereby, the fixing strength of the joint structure can be further increased.

  FIG. 5 is a cross-sectional view showing a third embodiment of the precast concrete column joining structure according to the present invention.

  As shown in FIG. 5, the precast concrete column joint structure according to the third embodiment has a recess 33 deeper than the recess 31 of the first embodiment on the upper surface of the column support structure 30. The bottom surface 10a of 10 is inserted in the recessed part 33, and is located below the upper end surface 30a of the column support structure 30.

  A coupler 12 and a communication hole 13 similar to those of the first embodiment are provided inside the precast concrete column 10, and an enlarged cylindrical portion 15 having a diameter larger than that of the lower end portion of the coupler 12 is provided below the coupler 12. Are connected continuously. The enlarged diameter cylindrical portion 15 is formed with the same height as the portion inserted into the recess 33. That is, in this embodiment, the filler injection flow path 14 is defined by the communication hole 13, the coupler 12, and the sleeve 16.

  The precast concrete column 10 has a length equivalent to the height of the spacer 20 inserted in the recess 33. That is, the height of the sleeve 16 is equal to the height of the spacer 20. On the other hand, the depth dimension of the recess 33 is equal to the combined length of the sleeve 16 and the spacer 20. In addition, the filler 50 is filled in the recess 33 up to the height of the upper end surface 30 a of the column support structure 30. As a result, the bottom of the precast concrete column 10 is accommodated in the filler 50 by the height of the sleeve 16, and the outer surface 10 b of the precast concrete column 10 is in close contact with the filler 50.

  According to the connection structure of the precast concrete columns configured as described above, the following operational effects can be obtained in addition to the operational effects similar to those of the first embodiment.

  According to the present embodiment, since the filler 50 contacts not only the bottom surface 10a of the precast concrete column 10 but also the outer surface 10b, the precast concrete column 10 is supported by the filler 50 from the left and right front-rear directions in FIG. As a result, the joining strength in the shear direction between the precast concrete column 10 and the column support structure 30 can be further increased.

  FIG. 6 is a sectional view showing a fourth embodiment of the precast concrete column joint structure according to the present invention. FIG. 7: is sectional drawing which showed the construction procedure of 4th embodiment of the joining structure of the precast concrete pillar based on this invention.

  In the joint structure of the precast concrete columns according to the third embodiment, the filling material 50 is filled in the whole of the recess 33 and the filler injection flow path 14, whereas the joint of the precast concrete columns according to the fourth embodiment. As shown in FIG. 6, the structure is characterized in that the joint filler 51 is filled in the coupler 12 and the communication hole 13 of the filler injection flow path 14 of the precast concrete column 10. Since other configurations are the same as those of the third embodiment shown in FIG. 5, the same reference numerals are given and description thereof is omitted.

  The joint filler 51 fills the inside of the coupler 12 and the communication hole 13 of the filler injection channel 14 after filling the concave portion 33 and the enlarged diameter cylindrical portion 15 with the filler 50 via the filler injection channel 14. Is done. The joint filler 51 is made of an expansive filler as in the second embodiment. When the joint filler 51 is cured in the coupler 12, the expansion force is increased to the main reinforcement 11 and the anchor reinforcement. 32 and the coupler 12 can be evenly applied to the entire surface, and the joint portion can be brought into a completely rigid joint state. Thereby, the fixing strength of the joint structure can be further increased. The filler 50 is filled up to the height of the upper end face 30 a of the column support structure 30 and is filled in the recessed portion 33 and the enlarged diameter cylindrical portion 15 of the precast concrete column 10.

  Next, the construction procedure of the precast concrete column joining structure having the above configuration will be described with reference to FIG.

  First, as shown in FIG. 7 (a), after reinforcing bars are placed in a mold (not shown), high-strength concrete is placed in the mold, and a column support structure having a recess 33 on the upper surface. 30 is formed. Here, the anchor bars 32 are arranged so as to protrude upward from the bottom surfaces 33 a of the four corners of the recess 33.

  Next, as shown in FIG. 7 (b), after the spacer 20 is installed in the substantially central portion of the concave portion 33 of the column support structure 30, precast concrete previously formed with ultrahigh strength concrete at a factory or the like. The pillar 10 is built from above the recess 33 and placed on the spacer 20. At this time, the upper portion of the anchor bar 32 is inserted into the coupler 12 from the bottom surface 10 a of the precast concrete column 10 through the enlarged diameter cylindrical portion 15. At this time, the installation height of the precast concrete pillar 10 can be easily guided by providing the spacer 20.

  Then, adjustment of erection accuracy, such as angle correction of the precast concrete pillar 10, is performed. At this time, since the spacer 20 is formed in the shape of a truncated cone, the angle of the protruding corner of the peripheral edge at the upper end is obtuse, and the precast concrete column 10 can be easily tilted and the angle can be easily corrected. In addition, breakage of the protruding corner portion of the spacer 20 hardly occurs.

  After the adjustment of the accuracy of erection of the precast concrete column 10 is completed, as shown in FIG. 7C, a plate-like filler overflow prevention plate 21 that covers the periphery of the recess 31 around the precast concrete column 10. Is installed. Thereafter, the filler 50 is injected from one portion of the lower communication hole 13 that opens to the side surface of the precast concrete column 10, passes through the coupler 12 and the sleeve 16, and fills the recess 33. At this time, since the filler 50 has appropriate fluidity, it can smoothly pass through the filler injection channel 14. When the concave portion 33 and the enlarged diameter cylindrical portion 15 are filled with the filler 50, the supply of the filler 50 is stopped. At this time, since the filler overflow prevention plate 21 is provided, the filler 50 does not overflow the surface of the column support structure 30. In addition, what is necessary is just to detect that the recessed part 33 and the enlarged diameter cylindrical part 15 are satisfy | filled by managing the supply amount of the filler 50. FIG. Thereafter, the joint filler 51 is sequentially injected from the communication holes 13 formed on the lower side of each coupler 12 and supplied into each coupler 12 to be filled. At this time, since the injected filler 50 overflows from the upper through holes 13 of each coupler 12, it can be confirmed that the filler 50 has been filled to that height. Thereafter, when the filler 50 is hardened by curing for a predetermined time, the filler overflow prevention plate 21 is removed, and the construction of the joining structure is completed.

  According to the connection structure of the precast concrete columns configured as described above, the joint filler 51 is cured in the coupler 12 in addition to the same effects as the third embodiment, so that the joint portion is completely rigid. It can be in a joined state. As a result, it is possible to obtain an effect that the fixing strength of the joint structure can be further increased.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said embodiment, In the range which does not deviate from the meaning of this invention, a design change is possible suitably. For example, the shapes of the precast concrete column 10 and the recesses 31 and 33 are not limited to a square cross section, and may be other shapes such as a circular cross section and a polygonal cross section.

It is sectional drawing which showed 1st embodiment of the joining structure of the precast concrete pillar which concerns on this invention. It is the sectional view on the AA line of FIG. (A) thru | or (c) is sectional drawing which showed sequentially the construction procedure of 1st embodiment of the joining structure of the precast concrete pillar which concerns on this invention. It is sectional drawing which showed 2nd embodiment of the joining structure of the precast concrete pillar which concerns on this invention. It is sectional drawing which showed 3rd embodiment of the joining structure of the precast concrete pillar which concerns on this invention. It is sectional drawing which showed 4th embodiment of the joining structure of the precast concrete pillar which concerns on this invention. (A) thru | or (d) is sectional drawing which showed sequentially the construction procedure of 4th embodiment of the joining structure of the precast concrete pillar concerning this invention. It is the side view which showed the joining structure of the conventional precast concrete pillar and beam material. It is the perspective view which showed the concrete test body for evaluating the intensity | strength of a junction part. It is the side view which showed the joining structure of the conventional precast concrete pillar and floor slab.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Precast concrete pillar 10a Bottom face 30 Column support structure 31 Recessed part 31a Bottom face 33 Recessed part 33a Bottom face 50 Filler

Claims (2)

In a joint structure for joining a precast concrete column to a column support structure having a strength lower than that of the precast concrete column,
Between the bottom surface of the recess formed on the top surface of the column support structure and the precast concrete column disposed above the recess with a predetermined interval, the precast concrete column has a strength higher than that of the column support structure. A joint structure for precast concrete columns, characterized in that a joint portion is formed by filling a filler having a strength less than the above strength. The joint structure of precast concrete columns according to claim 1, wherein a bottom surface of the precast concrete column is inserted into the recess and positioned below the upper end surface of the column support structure.

Images