Unbonded precast prestressed concrete structure and building equipped with the structure

Abstract

To prevent compression fracture of an unbonded PCaPC structure.SOLUTION: An unbonded PCaPC structure has a joint part that includes a first unbonded PCaPC column body that includes a first concrete member molded in a columnar shape and a tension material inserted into the first concrete member in an unbonded state and applied with tension, and a second unbonded PCaPC column body including a second concrete member molded in a columnar shape and a tension material inserted into the second concrete member in an unbonded state and applied with tension, and has the first unbonded PCaPC column body and the second unbonded PCaPC column body arranged vertically such that one end of the first unbonded PCaPC column body and one end of the second unbonded PCaPC column body face each other. In the joint part, end surfaces of one or both of the first concrete member and the second concrete member have peripheral edge parts shaped into curved surfaces.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to an unbonded precast prestressed concrete structure. An embodiment of the invention disclosed herein relates to an unbonded precast prestressed concrete column structure, an unbonded precast prestressed concrete column-beam joint structure. [Background technology]

[0002] Precast prestressed concrete (hereinafter, also referred to as "PCaPC") columns with tension applied in the vertical direction are known as columns used in high-rise buildings. PCaPC columns with tension applied have no residual deformation compared to normal precast concrete columns, and are therefore considered suitable for use in high-rise buildings. For example, a structure has been disclosed for a PCaPC column in which tension members are inserted into a plurality of tension member insertion holes formed in a concrete column body, the tension members are installed in a state of being tensioned, and the tension members are disposed in an unbonded state relative to the concrete column body (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-019664 A Summary of the Invention [Problem to be solved by the invention]

[0004] Compared to reinforced concrete structures, unbonded prestressed structures have open ends, which allows them to deform easily in the face of shaking and reduces damage. However, there is a problem in that damage is likely to occur at the ends of the legs and tops of the members when the covering concrete is compressed (hereinafter, this type of damage will be referred to as "crush" or "compression failure"). If compression failure occurs in unbonded PCaPC columns due to earthquakes, etc., it will cause a decrease in seismic resistance, so repairs to the compressed and failed parts will be necessary to maintain strength.

[0005] In view of such problems, an object of one embodiment of the present invention is to provide a structure capable of preventing compressive failure in an unbonded PCaPC structure. [Means for solving the problem]

[0006] An unbonded precast prestressed concrete structure according to one embodiment of the present invention includes a first unbonded precast prestressed concrete column including a first concrete member molded into a column shape and a tendon inserted into the first concrete member in an unbonded state and to which tension is applied, and a second unbonded precast prestressed concrete column including a second concrete member molded into a column shape and a tendon inserted into the second concrete member in an unbonded state and to which tension is applied. A joint is formed by arranging one end of the first unbonded precast prestressed concrete column and one end of the second unbonded precast prestressed concrete column in the vertical direction so as to face each other, and at the joint, the peripheral portion of one or both end faces of the first concrete member and the second concrete member are molded into a curved surface.

[0007] An unbonded precast prestressed concrete structure according to one embodiment of the present invention includes a first unbonded precast prestressed concrete column including a first concrete member molded into a column shape and a tendon inserted into the first concrete member in an unbonded state and to which tension is applied, a second unbonded precast prestressed concrete column including a second concrete member molded into a column shape and a tendon inserted into the second concrete member in an unbonded state and to which tension is applied, and a concrete member having a beam structure and including a beam-column joint. The first unbonded precast prestressed concrete column and the second unbonded precast prestressed concrete column are disposed above and below each other with a beam-column joint of the concrete members in between, and at the beam-column joint, the peripheral edge of one or both end faces of the first concrete member and the second concrete member are molded into a curved surface. Effect of the Invention

[0008] According to one embodiment of the present invention, by amplifying the displacement while avoiding compressive failure of the cover concrete at the end of an unbonded precast prestressed concrete column, it is possible to obtain an unbonded precast prestressed concrete structure that can absorb vibration energy by utilizing the displacement. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing the structure of a joint of an unbonded PCaPC column in one embodiment of the present invention. [Diagram 2] 1 is a schematic plan view showing the structure of a joint of an unbonded PCaPC column in one embodiment of the present invention. FIG. [Diagram 3] 1 is a schematic cross-sectional view showing the structure of a column-beam joint of an unbonded PCaPC column in one embodiment of the present invention. FIG. [Figure 4] 1 is a schematic plan view showing the structure of a column-beam joint of an unbonded PCaPC column in one embodiment of the present invention. FIG. [Diagram 5]This is a schematic cross-sectional view showing a structure in which a seismic control device is added to the joint of an unbonded PCaPC column in one embodiment of the present invention. [Figure 6] This is a schematic plan view showing a structure in which a seismic control device is added to the joint of an unbonded PCaPC column in one embodiment of the present invention. [Figure 7] This is a schematic cross-sectional diagram showing a structure in which a seismic control device is added to the column-beam joint of an unbonded PCaPC column in one embodiment of the present invention. [Figure 8] This is a schematic plan view showing a structure in which a seismic control device is added to the column-beam joint of an unbonded PCaPC column in one embodiment of the present invention. [Figure 9] This is a schematic plan view showing a structure in which a seismic control device is added to the column-beam joint of an unbonded PCaPC column in one embodiment of the present invention. [Figure 10] 1 is a schematic cross-sectional view showing the structure of a joint of an unbonded PCaPC column in one embodiment of the present invention. [Figure 11] 1 is a schematic plan view showing the structure of a joint of an unbonded PCaPC column in one embodiment of the present invention. FIG. [Figure 12] 1 is a diagram showing a schematic diagram of a concrete member and a formwork material manufactured by a precast concrete method in an unbonded PCaPC column according to one embodiment of the present invention. FIG. [Figure 13] 1 is a schematic cross-sectional view showing the structure of a column-beam joint of an unbonded PCaPC column in one embodiment of the present invention. FIG. [Figure 14] 1 is a schematic plan view showing the structure of a column-beam joint of an unbonded PCaPC column in one embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the contents of the embodiment of the present invention will be described with reference to the drawings. However, the present invention includes many different aspects, and is not to be interpreted as being limited to the contents of the embodiment exemplified below. In order to make the explanation clearer, the width, thickness, shape, etc. of each part may be shown diagrammatically compared to the actual aspect, but this is merely an example and does not limit the contents of the present invention. Furthermore, in this specification, when an element shown in a certain drawing and an element shown in another drawing are identical or correspond to each other, the same symbol (or a symbol with a, b, etc. added after the number shown as the symbol) may be added, and repeated explanations may be omitted as appropriate. Furthermore, the letters "first" and "second" added to each element are convenient marks used to distinguish each element, and have no further meaning unless otherwise explained.

[0011] [First embodiment] 1 shows a configuration of an unbonded PCaPC structure according to one embodiment of the present invention, in which the unbonded PCaPC structure has a columnar structure.

[0012] FIG. 1 shows a schematic cross-sectional structure of an unbonded PCaPC structure 100a according to this embodiment. The unbonded PCaPC structure 100a includes a first unbonded PCaPC pillar 102 and a second unbonded PCaPC pillar 112. The unbonded PCaPC structure 100a has a structure in which the first unbonded PCaPC pillar 102 and the second unbonded PCaPC pillar 112 are stacked in the vertical direction to form a single pillar. FIG. 1 shows a schematic cross-sectional structure of the unbonded PCaPC structure 100a, particularly the joint between the first unbonded PCaPC pillar 102 and the second unbonded PCaPC pillar 112. 2(A) shows a schematic planar structure of the first unbonded PCaPC pillar 102 (the structure when viewed from the A1 side in FIG. 1), and FIG. 2(B) shows a schematic planar structure of the second unbonded PCaPC pillar 112 (the structure when viewed from the B1 side in FIG. 1). In the following description, these drawings will be referred to as appropriate.

[0013] The first unbonded PCaPC column 102 includes a first concrete member (first precast concrete member) 104 molded into a column shape, and the second unbonded PCaPC column 112 includes a second concrete member (second precast concrete member) 114 molded into a column shape. The unbonded PCaPC structure 100a according to this embodiment has a structure in which one end of the first unbonded PCaPC column 102 and one end of the second unbonded PCaPC column 112 are overlapped and joined in the vertical direction so as to face each other.

[0014] The first concrete member 104 and the second concrete member 114 are molded to have a square cross section, and main reinforcement bars and hoop reinforcement bars (not shown) are embedded in them. The first concrete member 104 is provided with a first tendon insertion hole 105 passing through in the longitudinal direction, and the second concrete member 114 is provided with a second tendon insertion hole 115 passing through in the longitudinal direction. The first tendon insertion hole 105 is provided at a plurality of locations along the contour of the first concrete member 104 in a plan view. The first tendon insertion hole 105 is provided in an inner region of the first concrete member 104 so as to have a predetermined covering thickness from the surface. The second tendon insertion hole 115 is similarly provided in the second concrete member 114.

[0015] 2(A) and (B) show an example in which the first tendon insertion holes 105 and the second tendon insertion holes 115 are provided in a total of eight locations corresponding to the corners of the precast concrete member and the area between them, but there is no limit to the number of tendon through holes and they can be provided as appropriate. Furthermore, the cross-sectional shape of the first concrete member 104 and the second concrete member 114 is not limited to a square shape and may be an angular shape such as a rectangular shape or a hexagonal shape, or may be a circular shape or an elliptical shape.

[0016] In the first unbonded PCaPC column 102, the first tendon 106 is inserted through the first tendon insertion hole 105, and in the second unbonded PCaPC column 112, the second tendon 116 is inserted through the second tendon insertion hole 115. The first tendon 106 and the second tendon 116 have a structure in which, for example, a special grease is applied to the surface of a PC steel bar used as a core material, and the outer periphery is further covered with a plastic material such as polyethylene. The inner diameters of the first tendon insertion hole 105 and the second tendon insertion hole 115 are formed larger than the outer diameter of the tendon to be inserted. Therefore, a gap is formed between the inner wall of the first tendon insertion hole 105 and the first tendon 106, and a gap is formed between the inner wall of the second tendon insertion hole 115 and the second tendon 116. The first tendon 106 is not bonded to the concrete but is inserted through the first concrete member 104 in an unbonded state, and the second tendon 116 is similarly inserted through the second concrete member 114 in an unbonded state.

[0017] In the present invention, the unbonded state refers to a state in which the tendon is not joined to the concrete as described above, and is able to deform freely in its axial direction when the concrete column sways.

[0018] The unbonded PCaPC structure 100a in which the tendons are provided in an unbonded state is assembled, for example, as follows. The first concrete member 104 has a recess 130 at its upper end, and the first tendon insertion hole 105 is formed inside the recess 130. A plate 132 having a through hole through which the tendon can pass is arranged so as to overlap with the first tendon insertion hole 105. The first tendon 106 is provided with its upper portion protruding from the plate 132, and tension is applied to it by pulling it upwards with a jack or the like. The first tendon 106 is tightened by a nut 134 on the plate 132 with tension applied to it. Since the first tendon 106 is tightened by the nut 134, tension remains even when the jack or the like is removed.

[0019] Then, the upper end of the first tendon 106 is connected to the lower end of the second tendon 116 by a joint 136. Then, a cover material 138 that covers the first tendon 106 and the nut 134 is provided on the upper end of the first concrete member 104. In this state, the second concrete member 114 is lowered from above, and the upper end of the first concrete member 104 and the lower end of the second concrete member 114 are joined via grout 140. Then, the same operation is performed on the second concrete member 114 and the second tendon 116. In this manner, an unbonded PCaPC structure 100 in which the first unbonded PCaPC column 102 and the second unbonded PCaPC column 112 are joined is formed. The unbonded PCaPC structure 100a is in a state in which a compressive force is applied as a whole by the tendons (the first tendon 106 and the second tendon 116).

[0020] Such an unbonded PCaPC structure 100a has the advantage that it is stronger than normal reinforced concrete and is less likely to crack because compressive stress is applied to the first concrete member 104 and the second concrete member 114 by the tendons installed in an unbonded state. In addition, since the tendons (first tendons 106 and second tendons 116) that apply prestress have a restoring force, the unbonded PCaPC structure 100a has the advantage that it will return to its original state when an excessive load is temporarily applied to it and the load is removed.

[0021] In the event of lateral shaking during an earthquake, tensile stress acts on the foot of the column on the side where the lateral force acts and compressive stress acts on the opposite side, while compressive stress acts on the top of the column on the side where the lateral force acts and tensile stress acts on the opposite side. In this case, a concrete column with an unbonded column head and column base between the foundation slab and ceiling slab has the problem that the concrete cover at the end is prone to compressive failure when it is rotated and displaced by vibrations such as an earthquake. This type of compressive failure can also occur at the joints of columnar structures where concrete members are joined in an unbonded state, which is a problem.

[0022] In contrast, in the unbonded PCaPC structure 100a according to this embodiment, the peripheral portions 110 of the upper end of the first concrete member 104 and the lower end of the second concrete member 114 are formed in a curved shape. In other words, the peripheral portions 110 of the upper end of the first concrete member 104 and the lower end of the second concrete member 114 are not angular but have a curved shape. With such a shape of the end of the first concrete member 104 and the second concrete member 114, compressive stress is not concentrated at the end on the side that is compressed when the columnar body is rotated and displaced, so that compressive failure of the cover concrete can be prevented. In other words, the unbonded PCaPC structure 100a has a structure in which the first unbonded PCaPC column 102 and the second unbonded PCaPC column 112 have a curved shape at the end of the first concrete member 104 and the second concrete member 114, and thus easily absorbs energy that causes rotational displacement in the columnar body. The curved surface shapes formed on the ends of the first concrete member 104 and the second concrete member 114 are preferably provided around the entire periphery 110. Although not shown, it is also preferable that the lower end of the first concrete member 104 and the upper end of the second concrete member have similarly curved peripheral portions 110.

[0023] 1, 2(A) and 2(B) show an embodiment in which the peripheral portions 110 of both the upper end portion of the first concrete member 104 and the lower end portion of the second concrete member 114 have a curved shape, but the present invention is not limited to such an embodiment. For example, the same effect can be obtained even if only the peripheral portion 110 of one of the upper end portion of the first concrete member 104 and the lower end portion of the second concrete member 114 is provided with a curved shape.

[0024] The radius of curvature of the curved surface provided on the peripheral portion 110 at the ends of the first concrete member 104 and the second concrete member 114 may be equal to or less than the thickness of the covering concrete. In other words, it is preferable that the radius of curvature is smaller than the covering thickness of the concrete member on the tendon.

[0025] In this embodiment, the peripheral portions 110 at the ends of the first concrete member 104 and the second concrete member 114 have a curved shape, but in addition to such shapes, the peripheral portions 110 at the ends of the first concrete member 104 and the second concrete member 114 may have a shape that is chamfered at an angle of 30 degrees to 60 degrees, for example, an angle of 45 degrees. With such a chamfered shape, the same effect can be obtained.

[0026] As described above, the unbonded PCaPC structure according to this embodiment can prevent compressive failure of the cover concrete even when subjected to vibration energy due to an earthquake, etc. In other words, the unbonded PCaPC structure according to this embodiment resists minute vibrations with the rigidity of the building, and when subjected to large vibrations such as a major earthquake, amplifies the displacement while avoiding compressive failure of the cover concrete at the ends of the unbonded PCaPC column, and can absorb the vibration energy by utilizing the displacement.

[0027] [Second embodiment] This embodiment shows an example of an unbonded PCaPC structure having a beam-column joint structure. The following mainly describes the differences from the first embodiment.

[0028] Fig. 3 shows a schematic cross-sectional structure of an unbonded PCaPC structure 100b according to this embodiment. The unbonded PCaPC structure 100b includes a first unbonded PCaPC column 102 and a second unbonded PCaPC column 112 arranged on either side of a beam 122 formed of a concrete member 124. The first unbonded PCaPC column 102 is arranged below the beam 122 to form a column-beam joint, and the second unbonded PCaPC column 112 is arranged above the beam 122 to form a column-beam joint. Fig. 3 shows a schematic cross-sectional structure of a column-beam joint 120 of such an unbonded PCaPC structure 100b. 4(A) shows a schematic plan view of the beam-column joint 120 of the beam 122 (the structure when viewed from the A2 side shown in FIG. 3), and FIG. 4(B) shows a schematic plan view of the second unbonded PCaPC column 112 (the structure when viewed from the B1 side shown in FIG. 3). In the following description, these drawings will be referred to as appropriate.

[0029] The beam 122 is, for example, a precast concrete beam, and has a structure in which a third tendon insertion hole 125 is provided at the beam-column joint 120. The third tendon insertion hole 125 is provided at a position that matches the arrangement of the first tendon insertion hole 105 and the second tendon insertion hole 115. For example, as shown in FIG. 4(A), the third tendon insertion holes 125 are provided at eight locations corresponding to the arrangement of the second tendon insertion holes 115 provided in the second concrete member 114 (see FIG. 4(B)). In other words, as shown in FIG. 3, the third tendon insertion hole 125 is provided so as to communicate with the first tendon insertion hole 105 and the second tendon insertion hole 115.

[0030] A third tendon 126 is inserted into the third tendon insertion hole 125 and is connected to the first tendon 106 and the second tendon 116 by a joint 136. Although not shown, the first tendon 106 may be directly connected to the third tendon insertion hole 125 and connected to the second tendon 116 by the joint 136 at the second unbonded PCaPC column 112.

[0031] The joint between the first unbonded PCaPC column 102 and the beam 122 and the joint between the second unbonded PCaPC column 112 and the beam 122 are filled with grout 140. As in the first embodiment, the first unbonded PCaPC column 102 has a curved peripheral portion 110 at the upper end of the first concrete member 104, and the second unbonded PCaPC column 112 has a curved peripheral portion 110 at the lower end of the second concrete member 114. Since the ends of the first concrete member 104 and the second concrete member 114 have a curved shape with respect to the flat surface of the column-beam joint 120 formed on the lower and upper surfaces of the beam 122, even if the first unbonded PCaPC column 102 and the second unbonded PCaPC column 112 are rotated and displaced, compressive failure of the covering concrete can be prevented. Furthermore, the first unbonded PCaPC pillar 102 and the second unbonded PCaPC pillar 112 have a structure that is easily displaced by rotational displacement, and can absorb vibration energy by using the energy that utilizes that displacement.

[0032] As described above, the unbonded PCaPC structure 100b according to this embodiment has a column-beam joint, and the column-beam joint can prevent compressive failure of the cover concrete as in the first embodiment. In addition, the unbonded PCaPC structure 100b resists minute vibrations with the rigidity of the building, and when large vibrations such as a major earthquake occur, it amplifies the displacement while avoiding compressive failure of the cover concrete at the ends of the unbonded PCaPC columns, and can absorb vibration energy by utilizing the displacement.

[0033] [Third embodiment] This embodiment shows a configuration in which a vibration control device is added to the unbonded PCaPC structure shown in the first embodiment. In the following, the differences from the first embodiment will be mainly described.

[0034] Fig. 5 shows a schematic cross-sectional structure of an unbonded PCaPC structure 100c provided with a seismic control device 150. Fig. 6(A) shows a schematic planar structure of the first unbonded PCaPC column 102 (structure when viewed from the A3 side in Fig. 5), and Fig. 6(B) shows a schematic planar structure of the second unbonded PCaPC column 112 (structure when viewed from the B3 side in Fig. 5). In the following description, these drawings will be referred to as appropriate.

[0035] The vibration control device 150 is provided so as to bridge the first unbonded PCaPC column 102 and the second unbonded PCaPC column 112 across the joint. The vibration control device 150 can be attached to a columnar body, and there is no limitation on its structure as long as it can exert its effect. For example, the vibration control device 150 can be provided with a damper member between a pair of support members. In this case, one support member is fixed to the first unbonded PCaPC column 102, the other support member is fixed to the second unbonded PCaPC column, and the damper member is provided so as to cross the joint. For example, a steel damper, a friction damper, an oil damper, a viscous damper, a viscoelastic damper, etc. can be used as the vibration control device 150.

[0036] It is preferable that a plurality of vibration control devices 150 are provided along the outer circumference of the first unbonded PCaPC column 102 and the second unbonded PCaPC column 112. For example, as shown in Fig. 6 (A) and (B), the vibration control devices 150 may be provided at a total of eight locations to sandwich each corner of the first unbonded PCaPC column 102 and the second unbonded PCaPC column 112. In this way, by providing the vibration control devices 150 isotropically, it is possible to exert a vibration control function against stresses acting from various directions, regardless of the displacement of the column in a specific direction.

[0037] As explained in the first embodiment, the end of the first concrete member 104 has a curved peripheral portion 110, so that the first unbonded PCaPC column 102 is prone to rotational displacement when subjected to earthquake or other vibrations. The same is true for the second unbonded PCaPC column 112. In contrast, the unbonded PCaPC structure 100c according to this embodiment has a vibration control device 150 that acts to suppress rotational displacement during normal times (when stationary), improving stability. On the other hand, when subjected to earthquake or other vibrations, the vibration control device 150 absorbs vibration energy for a certain limit of vibration, and when vibrations exceed the limit of the vibration control device 150, the vibration energy is absorbed by utilizing the displacement of the column, improving the stability of the structure.

[0038] In this way, the unbonded PCaPC structure 100c of this embodiment has the same advantageous effects as the first embodiment, but with the addition of the vibration control device 150, it is possible to obtain a more stable columnar structure.

[0039] [Fourth embodiment] This embodiment shows a configuration in which a vibration control device is added to the unbonded PCaPC structure shown in the second embodiment. The following will mainly explain the differences from the second embodiment.

[0040] Fig. 7 shows a schematic cross-sectional structure of an unbonded PCaPC structure 100d equipped with a vibration control device. Fig. 8 shows a schematic planar structure of an unbonded PCaPC structure 100d equipped with a vibration control device (schematic structure when the cross section of the A4 part shown in Fig. 7 is viewed in plan). In the following description, these drawings will be referred to as appropriate.

[0041] The vibration control device 150 includes a first vibration control device 150a that is provided to bridge the first unbonded PCaPC column 102 and the beam 122 across the column-beam joint 120, and a second vibration control device 150b that is provided to bridge the second unbonded PCaPC column 112 and the beam 122 across the column-beam joint 120. The first vibration control device 150a and the second vibration control device 150b are the same as those shown in the third embodiment.

[0042] The first vibration control device 150a can be provided so as to bridge between the first unbonded PCaPC column 102 and the side portion of the beam 122, and between the first unbonded PCaPC column 102 and the upper surface portion of the beam 122. The second vibration control device 150b can be provided so as to bridge between the second unbonded PCaPC column 112 and the side portion of the beam 122, and between the second unbonded PCaPC column 112 and the upper surface portion of the beam 122. In this way, as shown in FIG. 8, multiple vibration control devices may be arranged to sandwich each corner of the first unbonded PCaPC column 102 and the second unbonded PCaPC column 112, and provided at a total of eight locations so as to bridge with the beam 122.

[0043] The mounting structure of the first vibration damping device 150a and the second vibration damping device 150b may be changed as appropriate. For example, the first vibration damping device 150a and the second vibration damping device 150b may be mounted so as to bridge the side of the column and the side of the beam. Also, the first vibration damping device 150a and the second vibration damping device 150b may be mounted so as to bridge the side of the column and the top surface of the beam.

[0044] Fig. 9 shows a schematic plan view of an unbonded PCaPC structure 100d in which the beam 122 is a cross beam. Fig. 9 shows the structure of the cross beam 123 and the second unbonded PCaPC column 112, and the second vibration control device 150b can be attached in the same manner as described above.

[0045] The column-beam joint structure as shown in FIG. 7 has a problem that the column is easily peeled off from the column-beam joint surface when the column is rotated. In contrast, in the unbonded PCaPC structure 100d according to this embodiment, the first vibration control device 150a and the second vibration control device 150b act to suppress the rotational displacement under normal conditions (when stationary), and the structural stability of the column-beam joint is enhanced. On the other hand, in the unbonded PCaPC structure 100d, when a vibration such as an earthquake acts, the first vibration control device 150a and the second vibration control device 150b absorb the vibration energy for a certain limit of the vibration, and when the vibration exceeds the limit of the first vibration control device 150a and the second vibration control device 150b, the displacement of the column is utilized to absorb the vibration energy, thereby enhancing the stability of the column-beam joint structure.

[0046] In this way, the unbonded PCaPC structure 100d of this embodiment has the same advantageous effects as the second embodiment, but also has a more stable column structure due to the addition of a vibration control device.

[0047] [Fifth embodiment] In this embodiment, the shapes of the ends of the unbonded PCaPC pillars arranged above and below are different from those of the unbonded PCaPC structure shown in the first embodiment. The following will mainly describe the parts that are different from the first embodiment.

[0048] Fig. 10 shows a schematic cross-sectional structure of an unbonded PCaPC structure 100e according to this embodiment. Fig. 11(A) shows a schematic planar structure of the first unbonded PCaPC pillar 102e (structure when viewed from the A5 side in Fig. 10), and Fig. 11(B) shows a schematic planar structure of the second unbonded PCaPC pillar 112e (structure when viewed from the B5 side in Fig. 10). In the following description, these drawings will be referred to as appropriate.

[0049] The first unbonded PCaPC column 102e includes a first concrete member 104e, and the second unbonded PCaPC column 112e includes a second concrete member 114e. The upper end of the first concrete member 104e and the lower end of the second concrete member 114e have a shape in which the peripheral portion 111 is formed in a tapered shape. In other words, the peripheral portion of the end face where the first concrete member 104e and the second concrete member 114e face each other has a tapered chamfered shape. That is, in the first embodiment, the peripheral portion of the concrete member at the joint between the first unbonded PCaPC column 102e and the second unbonded PCaPC column 112e is formed in a curved shape, but in this embodiment, it is formed in a tapered shape with a linear inclined surface.

[0050] 10, 11(A) and 11(B) show an example in which the cross-sectional shape of the first concrete member 104e and the second concrete member 114e is rectangular, but it is preferable that a tapered molding surface is formed on each face at the peripheral portion 111. Furthermore, if the cross-sectional shape of the first concrete member 104e and the second concrete member 114e is circular, it is preferable that the tapered molding surface at the peripheral portion 111 is formed around the entire circumference.

[0051] On the other hand, if the peripheral portion 111 of the end of the first concrete member 104e and the second concrete member 114e is formed in a tapered shape, the cross-sectional area of ​​the columnar body is reduced, and the axial force ratio increases, which may affect the earthquake resistance. In such a case, ultra-high strength concrete may be used for a part of the first concrete member 104a and the second concrete member 114a. Specifically, the first concrete member 104a may be formed from the upper end to a predetermined region, and the second concrete member 114e may be formed from the lower end to a predetermined region, using ultra-high strength concrete. In the first concrete member 104a and the second concrete member 114a, the length of the region formed with ultra-high strength concrete (length in the material axis direction) may be 100 mm to 500 mm, for example, about 200 mm.

[0052] 10 shows an example in which an ultra-high strength concrete region 103 is formed above a first concrete member 104e, and an ultra-high strength concrete region 113 is formed below a second concrete member 114e. In the first concrete member 104e and the second concrete member 114e, other regions may be formed of high strength concrete. Such a structure can be achieved by pouring concrete of different strengths in two stages during the manufacturing process of a concrete structure when pouring concrete using a precast concrete method.

[0053] In this way, by forming the joints of unbonded PCaPC columns out of high-strength concrete, it is possible to suppress the decrease in seismic resistance due to an increase in the axial force ratio, even if the peripheral part of the concrete at the joint is formed into a tapered shape.

[0054] The shapes of the first concrete member 104e and the second concrete member 114e shown in this embodiment can be formed by using formwork materials when pouring concrete by the precast concrete method. FIG. 12 shows a schematic diagram of the second concrete member 114e and formwork material 142 manufactured by the precast concrete method (the same applies to the first concrete member 104e). The formwork material 142 is placed in a formwork material (not shown) before pouring concrete. The formwork material 142 is arranged to correspond to each face of the second concrete member 114e. The cross-sectional shape of the formwork material 142 is a right-angled triangle, and it is arranged so that the sloped face contacts the poured concrete.

[0055] The material of the formwork material 142 may be appropriately selected, but it is preferable to use a foamable resin material such as polystyrene foam, a rubber material such as silicone rubber, a thermoplastic resin material (plastic), etc. By using such a material, the formwork material 142 can be easily molded.

[0056] The formwork material 142 may remain on the ends of the first concrete member 104e and the second concrete member 114e even after the concrete is poured. In other words, the formwork material 142 may be provided so as to abut against the tapered portions of the first concrete member 104e and the second concrete member 114e. The formwork material 142 remaining on the first concrete member 104e and the second concrete member 114e can also be used as a formwork material when filling the grout 140.

[0057] In addition, the formwork material 142 may remain in the unbonded PCaPC structure 100e as it is. By having the formwork material 142 at the joint between the first unbonded PCaPC column 102e and the second unbonded PCaPC column 112e, when a force acts in the horizontal direction due to an earthquake or the like, the formwork material 142 can absorb the energy by deformation and destruction, thereby reducing damage.

[0058] The unbonded PCaPC structure according to this embodiment, like that of the first embodiment, can prevent compressive failure of the cover concrete even when vibration energy due to an earthquake or the like acts on it. Furthermore, the unbonded PCaPC structure according to this embodiment can be easily constructed because the concrete members can be cast using formwork materials in the precast concrete construction method. Furthermore, the unbonded PCaPC structure according to this embodiment can increase earthquake resistance by absorbing part of the energy of rotational displacement with the formwork materials.

[0059] The joint structure shown in this embodiment can also be applied to the unbonded PCaPC structure shown in the third embodiment, and the effects obtained in this embodiment can be obtained in addition to the effects obtained in the third embodiment.

[0060] [Sixth embodiment] In this embodiment, the shapes of the ends of the unbonded PCaPC pillars arranged above and below are different from those of the unbonded PCaPC structure shown in the second embodiment. The following will mainly describe the parts that are different from the second embodiment.

[0061] FIG. 13 shows a schematic cross-sectional structure of an unbonded PCaPC structure 100f according to this embodiment. The unbonded PCaPC structure 100f includes a first unbonded PCaPC column 102f and a second unbonded PCaPC column 112f arranged on either side of a beam 122 formed of a concrete member 124. The first unbonded PCaPC column 102f is arranged on the lower side of the beam 122 to form a column-beam joint, and the second unbonded PCaPC column 112f is arranged on the upper side of the beam 122 to form a column-beam joint. FIG. 14(A) shows a schematic planar structure of the beam-beam joint 120 of the beam 122 (the structure when the A6 side shown in FIG. 13 is viewed in plan), and FIG. 14(B) shows a schematic planar structure of the second unbonded PCaPC column 112f (the structure when the B6 side shown in FIG. 13 is viewed in plan). In the following description, these drawings will be referred to as appropriate.

[0062] As in the fifth embodiment, the upper end of the first concrete member 104f of the first unbonded PCaPC column 102f and the lower end of the second concrete member 114f have a tapered peripheral portion 111. The peripheral portion 111 may also be provided with a formwork material 142.

[0063] The ends of the first concrete member 104f and the second concrete member 114f are tapered relative to the flat surfaces of the beam-column joint 120 formed on the lower and upper surfaces of the beam 122, so that compressive failure of the cover concrete can be prevented even if the first unbonded PCaPC column 102f and the second unbonded PCaPC column 112f undergo rotational displacement. In addition, by arranging formwork materials 142 at the ends of the first concrete member 104f and the second concrete member 114f, part of the energy of the rotational displacement can be absorbed.

[0064] As described above, the unbonded PCaPC structure according to this embodiment has a column-beam joint, and the column-beam joint can prevent compressive failure of the cover concrete even when vibration energy due to an earthquake or the like acts on the column-beam joint, as in the fifth embodiment. Furthermore, the unbonded PCaPC structure according to this embodiment can be easily constructed because the concrete members can be molded using formwork materials in the precast concrete construction method. In addition, the unbonded PCaPC structure according to this embodiment can increase earthquake resistance by absorbing part of the energy of rotational displacement with formwork materials.

[0065] The joint structure shown in this embodiment can also be applied to the unbonded PCaPC structure shown in the fourth embodiment, and the effects obtained in this embodiment can be obtained in addition to the effects obtained in the third embodiment. [Industrial Applicability]

[0066] The unbonded PCaPC structures according to the first to sixth embodiments can be used as columns or column-beam structures of high-rise buildings and the like. [Explanation of symbols]

[0067] 100 unbonded PCaPC structure, 102 first unbonded PCaPC column, 104 first concrete member, 105 first tendon insertion hole, 106 first tendon, 110 periphery, 111 periphery, 112 second unbonded PCaPC column, 113 ultra-high strength concrete region, 114 second concrete member, 115 second the tendon insertion hole, 116... second tendon, 120... column-beam joint, 122... beam, 123... cross beam, 124... concrete member, 125... third tendon insertion hole, 126... third tendon, 130... recess, 132... plate, 134... nut, 136... joint, 138... cover material, 140... grout, 142... formwork material, 150... seismic control device

Claims

1. A first unbonded precast prestressed concrete column including a first concrete member molded into a column shape and a tendon inserted in an unbonded state through the first concrete member and to which tension is applied; A second unbonded precast prestressed concrete column including a second concrete member molded into a column shape and a tendon inserted in an unbonded state through the second concrete member and to which tension is applied; Including, A joint is formed by one end of the first unbonded precast prestressed concrete column and one end of the second unbonded precast prestressed concrete column being arranged in an up-down direction so as to face each other, At the joint, one or both end surfaces of the first concrete member and the second concrete member are tapered, The end surface is in contact with a formwork material.

1. An unbonded precast prestressed concrete structure.

2. The present invention further includes a seismic control device arranged to bridge the first unbonded precast prestressed concrete column and the second unbonded precast prestressed concrete column across the joint.

2. The unbonded precast prestressed concrete structure of claim 1.

3. The vibration control device includes a type selected from a steel damper, a friction damper, an oil damper, a viscous damper, and a viscoelastic damper.

3. The unbonded precast prestressed concrete structure of claim 2.

4. The formwork material is in contact with the tapered region.

2. The unbonded precast prestressed concrete structure of claim 1.

5. A first unbonded precast prestressed concrete column including a first concrete member molded into a column shape and a tendon inserted in an unbonded state through the first concrete member and to which tension is applied; A second unbonded precast prestressed concrete column including a second concrete member molded into a column shape and a tendon inserted in an unbonded state through the second concrete member and to which tension is applied; A concrete member having a beam structure and including a beam-column joint; Including, The first unbonded precast prestressed concrete column and the second unbonded precast prestressed concrete column are arranged vertically with the column-beam joint of the concrete member in between, In the column-beam joint, the peripheral portion of one or both end surfaces of the first concrete member and the second concrete member is molded into a curved surface, The end surface is in contact with a formwork material.

1. An unbonded precast prestressed concrete structure.

6. a first seismic control device provided to bridge the first unbonded precast prestressed concrete column and the concrete member across the column-beam joint; and a second seismic control device provided to bridge the second unbonded precast prestressed concrete column and the concrete member across the column-beam joint.

6. An unbonded precast prestressed concrete structure as claimed in claim 5.

7. The radius of curvature of the curved surface is smaller than the thickness of concrete covering the tendon.

7. An unbonded precast prestressed concrete structure according to claim 5 or 6.

8. The first and second vibration damping devices include a type of damper selected from a steel damper, a friction damper, an oil damper, a viscous damper, and a viscoelastic damper.

7. An unbonded precast prestressed concrete structure as claimed in claim 6.

9. In the column-beam joint, the peripheral portion of one or both end faces of the first concrete member and the second concrete member is formed into a tapered shape instead of a curved surface.

9. An unbonded precast prestressed concrete structure according to any one of claims 5 to 8.

10. The formwork material is in contact with the tapered region.

10. The unbonded precast prestressed concrete structure of claim 9.

11. A building comprising an unbonded precast prestressed concrete structure according to any one of claims 1 to 10.

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