JP6422795B2 - Composite beam, PCa composite beam member constituting the same, and composite ramen structure - Google Patents

Description

  The present invention relates to a composite beam made of different strength concrete in which the central part of the member in the cross section is made of high-strength concrete and the outer periphery of the member is made of relatively low-strength concrete, the PCa composite beam member for constructing this, and the different-strength concrete. Concerning composite ramen structure.

  In recent years, research and development on increasing the strength of concrete has been actively conducted, and concrete strength has been dramatically increased by reducing the water cement ratio with high-performance AE water reducing agents and reducing the water binder ratio by blending various admixtures. It has become. The strength of high-strength concrete (design standard strength) depends on the type of cement and admixture, but generally increases as the water binder ratio decreases. Such high strength of concrete makes it possible to increase the height of buildings and reduce the cross section of columns, and is now widely used in high-rise buildings.

  As an example of using high-strength concrete as a column, the outer part of the column is formed by a precast (hereinafter referred to as PCa) concrete member using ultra-high-strength concrete, and the inside of the outer shell is hollow or low-strength concrete. Is known (see Patent Documents 1 and 2).

  Although high-strength concrete is not used, as an example of using a PCa concrete member for a part of the beam, two PCa plates are placed opposite each other on both sides of the beam cross-section divided into three by the vertical dividing line. Once the two PCa concrete plates are arranged at the construction position of the beam, the cast-in-place concrete is filled between the two PCa concrete plates at the beam end, In the section, a composite underground beam having a hollow portion between two PCa concrete plates is known (see Patent Document 3).

  As another example of a beam using a PCa concrete member, a beam is formed so that a plurality of beam main bars arranged on the outer periphery of the cross section, a shear reinforcement bar surrounding the plurality of beam main bars, and a vertical penetration space are formed. A half precast beam is also known which includes a pair of PCa concrete plates that are disposed opposite to each other at both lower portions of the steel plate and in which a part of the main reinforcing bar and the shear reinforcing bar are arranged inside (see Patent Document 4).

  In the beams described in Patent Document 3 and Patent Document 4, it is possible to use a PCa concrete plate as a formwork when placing cast-in-place concrete.

JP 2006-233548 A JP 2004-332236 A JP 2003-49435 A JP 2012-241311 A

  In general, RC beams are often constructed of concrete of uniform strength. Here, when considering using high-strength concrete for the beam in order to reduce the cross-section or to improve the shear strength and bending strength, using the configuration of the beam in Patent Document 3 and Patent Document 4, It is conceivable to form the PCa concrete plate from high-strength concrete. However, it has been pointed out that high-strength concrete tends to explode at the time of a fire due to the dense structure. Therefore, when using high-strength concrete on both sides of the beam, synthetic fiber is mixed in the concrete to cover the surface of the frame to reduce thermal stress during fires or to reduce water vapor pressure during fires. Measures such as to do are necessary. In addition, high strength concrete tends to increase the self-shrinkage strain while the elastic strain, creep strain, and drying shrinkage strain decrease as the strength increases. For this reason, when high-strength concrete is used on both sides of the beam, self-shrinkage of the high-strength concrete is constrained by the beam main bars arranged on both sides, and cracks are likely to occur.

  The present invention has been made in view of such a background, and it is possible to provide a composite beam and a composite beam that can ensure fire resistance and effectively prevent the occurrence of cracks, reduce the cross-sectional area, or improve the yield strength. It is an object of the present invention to provide a PCa composite beam member and a composite rigid frame structure to be used.

  In order to solve the above-mentioned problems, the present invention is made of high-strength concrete having a predetermined water binder ratio and strength, and has a beam center portion (21) disposed in the center portion of the cross section and water as compared with the high-strength concrete. It is made of concrete with a high binder ratio and low strength, and has a beam outer peripheral part (22) arranged on the outer peripheral part of the cross section so as to cover the entire peripheral surface of the central part of the beam, and has a beam main reinforcement (26) and a reinforcing bar (27) provides a composite beam (2) characterized in that it is arranged only on the outer periphery of the beam. Here, high-strength concrete is concrete that achieves high strength by having a relatively low water binder ratio, and does not include concrete that achieves high strength by mixing substances other than the binder.

  According to this structure, since the beam center part which consists of high-strength concrete is covered with a beam outer peripheral part, the fireproof performance of a beam is securable. Further, since the central portion of the beam is not constrained by the main beam of the beam, the high-strength concrete can be freely self-contracted, and cracks resulting from self-contraction can be prevented from occurring in the central portion of the beam. Furthermore, by using high-strength concrete, the cross-sectional area of the beam can be reduced or the proof stress of the beam can be improved. In particular, the use of high-strength concrete at the center of the beam can effectively improve the shear strength of the beam.

  Further, the present invention may be configured such that, in at least a part of the cross section, the lower surface of the central portion of the beam is inclined or curved so as to advance upward from the central side toward the outer side. .

  According to this structure, it can suppress that air accumulates on the lower surface of a beam center part at the time of concrete placement of a beam outer peripheral part.

  Moreover, this invention can set it as the structure by which the side surface of the said beam center part is exhibiting the uneven | corrugated shape which consists of a curve in a cross section in said structure.

  According to this configuration, while preventing the air from accumulating on the side surface of the beam center when the concrete is placed on the outer periphery of the beam, the coupling force between the beam outer periphery where the main bar and the reinforcing bar are arranged and the beam center is increased. The shear strength can be improved reliably.

  In order to solve the above-mentioned problems, the present invention provides a PCa composite beam member (20) for constructing a composite beam having the above-described configuration, in which the beam center portion and at least the lower portion of the beam outer peripheral portion are PCa concrete. The PCa composite beam member is characterized in that the beam center portion protrudes from the beam outer peripheral portion at both ends in the axial direction.

  According to this configuration, when building the PCa concrete on the outer periphery of the beam, it is possible to assemble the formwork and rebar and place the concrete while supporting the portion protruding from the outer periphery of the beam at the center of the beam. it can. Therefore, the manufacture of the PCa composite beam member can be facilitated. Further, the PCa composite beam member can be arranged so that only the protruding portion at the center of the beam is located inside the column. Thereby, the center part of the beam made of high-strength concrete can be made to enter the inside of the column while reducing the number of column main bars penetrating the PCa composite beam member.

  In order to solve the above problems, the present invention has a column (1) and a beam (2) which are rigidly connected to each other, and a column center (11) and a beam center ( 21) is made of high-strength concrete having a predetermined water binder ratio and strength, and is arranged on the outer periphery of the member cross-section so as to cover the entire peripheral surfaces of the center of the column and the center of the beam. (12) and the beam outer peripheral part (22) is a composite ramen structure (100) made of concrete having a higher water binder ratio and lower strength than the high-strength concrete, and at least the central part of the pillar is made of PCa concrete. A PCa composite beam member (PCa composite beam member (10) which is spanned between a plurality of PCa column members (10) and a pair of the columns (1, 1), and in which the beam central portion and at least the lower portion of the beam outer peripheral portion are made of PCa concrete. 0)), and the PCa composite beam member is formed such that the beam center portion protrudes from the outer periphery of the beam at both ends in the axial direction, and the protruding portion (23) of the beam center portion is formed of the column. It is set as the structure arrange | positioned so that it may be located inside and may connect with the said column center part.

  According to this configuration, when building the PCa concrete on the outer periphery of the beam, it is possible to assemble the formwork and rebar and cast the concrete while supporting both ends (protruding portions) of the beam center. it can. Therefore, the manufacture of the PCa composite beam member can be facilitated. In addition, since the column central portion and the beam central portion are respectively composed of the PCa column member and the PCa composite beam member, the quality control of the high-strength concrete can be facilitated. Furthermore, since only the protruding portion of the beam central portion of the PCa composite beam member is located inside the column, the PCa composite beam member penetrates while connecting the beam central portion of the PCa composite beam member to the column central portion of the PCa column member. The number of column main bars to be reduced can be reduced.

  Moreover, this invention can set it as the structure by which the said beam center part of the said PCa composite beam member and the said column center part of the said PCa column member are connected by the cotter type joint (3) in said structure. .

  According to this configuration, the load transmitted from the beam to the column can be reliably transmitted from the member central portion of the PCa composite beam member to the member central portion of the PCa column member, and the high compressive strength of the high-hardness concrete is effectively obtained. Can be used.

  As described above, according to the present invention, the cross-sectional area of the beam can be reduced or the strength of the beam can be improved, fire resistance can be ensured and cracking can be effectively prevented, and PCa for constructing the composite beam. A composite beam member as well as a composite frame structure can be provided.

Side view of composite ramen structure according to embodiment 1 is a perspective view of the PCa composite column member shown in FIG. Sectional drawing of the PCa composite pillar member shown along line III-III in FIG. 1 is a perspective view of the PCa composite beam member shown in FIG. Side view of the PCa composite beam member shown in FIG. Side view of the main part of the beam center shown in FIG. Sectional drawing of the PCa composite beam member shown along the VII-VII line in FIG. Sectional drawing of the PCa composite beam member shown along line VIII-VIII in FIG. Sectional drawing of the PCa composite beam member concerning a modification Sectional drawing of the PCa composite beam member concerning a modification

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, a composite rigid frame structure 100 includes a plurality of composite columns 1 and a plurality of composite beams 2 that are spanned between a pair of adjacent composite columns 1, 1 and that are rigidly coupled to the composite columns 1 at both ends. have. In the composite ramen structure 100, composite pillars 1 are arranged along two directions orthogonal to each other on a plane, and a pair of adjacent composite pillars 1 and 1 are connected by a composite beam 2 extending along each direction. . FIG. 1 shows only one of them.

  In the composite rigid frame structure 100, the central part of the cross section of the composite column 1 and the composite beam 2 is made of high-strength concrete having a relatively low water binder ratio and a relatively high strength. It is a composite concrete structure made of concrete (hereinafter referred to as ordinary concrete) having a high water binder ratio and a relatively low strength compared to the central portion of the cross section. Here, high-strength concrete means concrete having a lower water binder ratio and higher strength than ordinary concrete, and does not define an upper limit value or a lower limit value of strength of the water binder ratio.

  In this embodiment, the composite column 1 is constructed by sequentially stacking PCa composite column members 10 having a length corresponding to the height of one floor, and the composite beam 2 has a length corresponding to the span of the composite column 1 in the axial direction. The PCa composite beam member 20 having the following structure is rigidly coupled to the composite column 1 (the upper end of the PCa composite column member 10). In other embodiments, the PCa composite column member 10 may be shorter or longer than the floor height of one layer. Further, a part of the composite column 1 or the composite beam 2 (for example, a column outer peripheral portion 12 to be described later) may be constructed by cast-in-place concrete. In addition, since the column center part 11 and the beam center part 21 which are mentioned later are formed with high-strength concrete, it is preferable to pre-cast in a factory.

  As shown in FIGS. 2 and 3, the PCa composite column member 10 is disposed at the outer peripheral portion of the cross section so as to cover the column central portion 11 of the square cross section disposed at the central portion of the cross section and the entire side surface of the column central portion 11. The outer edge to be formed has a rectangular column outer peripheral portion 12. The column central portion 11 is a substantially unreinforced concrete structure made of high-strength concrete. On the other hand, the column outer peripheral portion 12 is a reinforced concrete structure made of ordinary concrete having a higher water binder ratio and lower strength than the column central portion 11.

  Either the high-strength concrete that forms the column central portion 11 or the ordinary concrete that forms the column outer peripheral portion 12 may be placed first. However, the high-strength concrete is free to self-shrink to generate cracks. In order to prevent this, it is preferable that the column central portion 11 is constructed first using high-strength concrete (including precast formation), and the column outer peripheral portion 12 is constructed later using ordinary concrete. The column central portion 11 and the column outer peripheral portion 12 are integrated with each other by adhesion of concrete to be placed later.

  In the upper part of the column outer peripheral part 12, a notch 13 (joint hole) for arranging a beam center part 21 to be described later is provided on each of the side surfaces (four side surfaces in the illustrated example) to which the PCa composite beam member 20 is connected. Is formed. The notch 13 is opened in the side surface and the upper surface of the PCa composite column member 10, and is formed over the entire thickness of the column outer peripheral portion 12. Therefore, the side surface of the column central portion 11 is exposed at the portion where the notch 13 is formed. The notch 13 may be open only on the side surface of the PCa composite column member 10. A concave portion 14 or a convex portion 15 constituting the cotter joint 3 is formed in the exposed portion of the column central portion 11.

  In addition, a through hole 1a for inserting the beam main reinforcing bar 26 (see FIG. 9) is formed at the upper end portion of the PCa composite column member 10 serving as a joint for connecting the composite column 1 and the composite beam 2. .

  A plurality of (20 in this case) column main bars 16 are arranged in the vicinity of the outer peripheral edge of the composite column 1 inside the column outer peripheral portion 12, and an axis so as to surround the plurality of column main bars 16. A plurality of rectangular strip reinforcing bars 17 (shear reinforcement bars) arranged at predetermined intervals in the direction are embedded. The column main reinforcing bars 16 and the belt reinforcing bars 17 are arranged only on the column outer peripheral portion 12.

  A sleeve joint 18 is provided at the upper end or lower end (upper end in the illustrated example) of the column main reinforcement 16, and the lower end or upper end (lower end in the illustrated example) of the column main reinforcement 16 is disposed below or above (lower in the illustrated example). It is connected with the sleeve joint 18 of the PCa composite column member 10 to be made.

  Thus, the composite pillar 1 has a form in which high-strength concrete is not used because of the use of high-strength concrete in a part of the cross-section (the entire cross-section is formed by ordinary concrete forming the column outer peripheral portion 12). Compared to the embodiment), the compressive strength can be increased, and the column cross-sectional area necessary for obtaining the same compressive strength can be reduced. In addition, since the column central portion 11 made of high-strength concrete is covered with the column outer peripheral portion 12, the surface portion of the composite column 1 is less likely to explode in the event of a fire, and the fire resistance performance of the composite column 1 is ensured. Yes.

  In addition, the column center part 11 does not need to be perfect unreinforced concrete, and the unreinforced concrete said here does not contain the column main reinforcement 16 and PC steel materials which restrain the self-contraction of the axial direction of high-strength concrete. Means. Therefore, the column central portion 11 has a configuration in which an intermediate strip reinforcing bar extending in the cross-sectional direction is embedded, or a reinforcing bar that is not considered in the structural calculation, such as a set-up reinforcing rod, even in the axial direction. It may be a configuration.

  As shown in FIGS. 4 and 5, the PCa composite beam member 20 has a beam central portion 21 arranged at the central portion of the cross section and an outer edge arranged at the outer peripheral portion of the cross section so as to cover the peripheral surface of the beam central portion 21. And a rectangular beam outer peripheral portion 22. The beam central portion 21 is a substantially unreinforced concrete structure made of high-strength concrete and has a length longer than the distance between the pair of composite columns 1 and 1. On the other hand, the beam outer peripheral portion 22 is a reinforced concrete structure made of ordinary concrete having a higher water binder ratio and lower strength than the beam central portion 21, and has a length substantially equal to the distance between the pair of composite columns 1, 1. Yes. That is, the beam outer peripheral portion 22 covers the entire peripheral surface of the portion disposed between the pair of composite columns 1 and 1 in the beam central portion 21. Both ends in the axial direction of the beam central portion 21 are protruding portions 23 (tenons) protruding from the beam outer peripheral portion 22. The protruding portion 23 is inserted into the notch 13 of the column outer peripheral portion 12 as shown in FIG. After the protrusion 23 is disposed in the notch 13, the upper portion of the notch 13 is filled with concrete or mortar.

  On each of the end surfaces of the beam central portion 21, a convex portion 24 or a concave portion 25 that is engaged with the concave portion 14 or the convex portion 15 of the column central portion 11 and constitutes the cotter joint 3 is formed. That is, the beam center portion 21 of the PCa composite beam member 20 indicated by an imaginary line in FIG. 2 is integrally coupled to the column center portion 11 by the cotter joint 3. A joint (not shown) is provided between the PCa composite beam member 20 and the PCa composite pillar member 10, and the joint is filled with grout such as non-shrink mortar.

  In the PCa composite beam member 20 of the present embodiment, the entire beam outer peripheral portion 22 is previously formed of PCa concrete, but the upper portion is buried in the floor slab (that is, the floor slab is coupled to the side surface of the composite beam 2). In the case where the concrete of the upper part of the beam outer peripheral part 22 is not yet placed. That is, at least the lower part of the beam central portion 21 and the beam outer peripheral portion 22 is formed of PCa concrete to form a PCa composite beam member 20, and after the PCa composite beam member 20 is arranged on the site, the beam outer periphery is simultaneously formed with the floor slab by the cast-in-place concrete. The upper part of the part 22 may be constructed.

  As shown in FIG. 7, a plurality of (eight in this case) beam main bars 26 arranged in the vicinity of the outer peripheral edge of the composite beam 2 and extending in the axial direction are disposed inside the beam outer peripheral portion 22. A plurality of rectangular reinforcing bars 27 (shear reinforcement bars) arranged at predetermined intervals in the axial direction so as to surround the beam main reinforcing bars 26 are embedded. The main beam bars 26 and the reinforcing bar 27 are disposed only on the outer circumferential portion 22 of the beam.

  However, similarly to the column central portion 11, the beam central portion 21 does not need to be completely unreinforced concrete, and does not have to include the beam main reinforcement 26 or the PC steel material that restrains the self-shrinkage of the high-strength concrete in the axial direction. . The beam center portion 21 has a structure in which width-reducing bars and steady-rest bars extending in the cross-sectional direction and bending bars that penetrate diagonally are embedded, and reinforcing bars that are not considered in the structural calculation extending in the axial direction are embedded. It may be a configuration.

  A sleeve joint 28 is provided at one end (the left end in the illustrated example) of the beam main reinforcing bar 26, and the other end (the right end in the illustrated example) of the beam main reinforcing bar 26 protrudes from the end surface of the beam outer peripheral portion 22. The portion is inserted into the through hole 1a of the PCa composite column member 10, and further connected to the sleeve joint 28 of the PCa composite beam member 20 disposed at a position sandwiching the PCa composite column member 10. Alternatively, a sleeve joint 28 is also provided at the other end of the beam main bar 26, an insertion beam main bar (not shown) is inserted into the through hole 1 a of the PCa composite column member 10, and PCa disposed on both sides of the PCa composite column member 10. The beam main reinforcement 26 of the composite beam member 20 may be connected via the sleeve joint 28 and the insertion beam main reinforcement.

  As shown in FIGS. 6 and 7, on each of the side surfaces of the beam central portion 21, concave stripes 31 that are inclined at a predetermined angle to the left and right with respect to the vertical direction are formed at a relatively small interval. In the present embodiment, the concave strip 31 is inclined at 45 degrees with respect to the vertical direction on both the left and right sides. It can be said that a portion surrounded by a total of four concave stripes 31 that are inclined to the left and right is a square protrusion 32, and the protrusion 32 is formed on the side surface of the beam center portion 21. Thereby, the side surface of the beam center part 21 is made into the uneven shape which consists of a curve in a cross section. Alternatively, a ridge is formed on each of the side surfaces of the beam center portion 21 instead of the ridge 31, and a portion surrounded by a total of four ridges that are inclined to the left and right is a square recess. Also good.

  As shown in FIG. 8, in at least a partial cross section in the axial direction of the PCa composite beam member 20, the lower surface of the beam central portion 21 is curved so as to advance upward as it goes outward from the center side. ing. Hereinafter, a portion where the lower surface of the beam central portion 21 has such a shape is referred to as an air bleeding portion 33. Although the air vent part 33 should just be formed in at least one part of the part covered with the beam outer peripheral part 22, in this embodiment, the several air vent part 33 is formed at intervals in an axial direction, and air The length in the axial direction and the interval of the punched portion 33 are approximately the same.

  When constructing the PCa composite beam member 20, in order to prevent the high-strength concrete from self-shrinking so that cracks do not occur, the beam center portion 21 is constructed first using the high-strength concrete, It is preferable to construct the beam outer peripheral portion 22 from ordinary concrete (including the case of on-site casting).

  As described above, since the composite beam 2 has the beam central portion 21 made of high-strength concrete and the beam outer peripheral portion 22 made of ordinary concrete, the fire resistance performance of the composite beam 2 is ensured. Further, since the beam main bars 26 and the reinforcing bars 27 are arranged only on the beam outer peripheral portion 22, the high-strength concrete in the beam central portion 21 can freely self-shrink without being constrained by the beam main bars 26. It is suppressed that the crack resulting from this occurs in the beam center part 21.

  Furthermore, since high-strength concrete is used for a part of the composite beam 2, the cross-sectional area of the composite beam 2 can be reduced or the shear strength can be improved. That is, the shearing force of the composite beam 2 is exerted by applying a tensile force to the beam main bar 26 and the reinforcing bar 27 as shown by arrows in FIG. Therefore, even if the tensile strength of the beam main bar 26 and the reinforcing bar 27 is large, the shear force of the composite beam 2 does not increase when the compressive strength of concrete is small. In this embodiment, since a part of the composite beam 2 is made of high-strength concrete, the compressive force against the shear force is increased, and the shear strength of the composite beam 2 is improved. In particular, the main beam 26 and the reinforcing bar 27 are disposed on the outer circumferential portion 22 of the beam. However, since the compressive force against the shear force is applied to the entire composite beam 2, the use of high-strength concrete at the center of the cross section. The shear strength is effectively increased.

  When constructing the PCa composite beam member 20, it is preferable to construct the beam central portion 21 first as described above and the beam outer peripheral portion 22 later. However, the beam outer peripheral portion 22 needs to cover the lower surface of the beam central portion 21, and a plurality of beam main bars 26 are disposed below the beam outer peripheral portion 22. For this reason, air tends to accumulate on the lower surface of the beam central portion 21 when placing ordinary concrete for constructing the beam outer peripheral portion 22. In the present embodiment, the air vent portion 33 is formed in at least a part of the cross section, so that when the concrete of the beam outer peripheral portion 22 is placed, the air easily escapes from the lower side of the beam central portion 21 to the side. Therefore, air is suppressed from being accumulated on the lower surface of the beam central portion 21. That is, the concrete can be spread to the lower part of the beam outer peripheral portion 22 to build a dense concrete.

  Further, in the present embodiment, the side surface of the beam central portion 21 has an uneven shape in the cross section, so that the air coming out from below the beam central portion 21 does not remain on the protrusion 32 on the side surface and remains outside the concrete. While being able to discharge | emit, the joint strength of the beam center part 21 and the beam outer peripheral part 22 can be made high, and the shear strength of the composite beam 2 can be improved.

  In this embodiment, in order to construct the composite beam 2, at least the lower part of the beam central part 21 and the beam outer peripheral part 22 is formed of PCa concrete, and the beam central part 21 protrudes from the beam outer peripheral part 22 at both ends in the axial direction. The PCa composite beam member 20 is used. Therefore, when building the PCa concrete of the beam outer peripheral portion 22, it is possible to assemble the formwork and rebar and cast the concrete while supporting the portion protruding from the beam outer peripheral portion 22 of the beam central portion 21. The manufacture of the PCa composite beam member 20 is facilitated. Further, since the PCa composite beam member 20 can be arranged so that only the protruding portion 23 of the beam central portion 21 is located inside the composite column 1, the number of column main bars 16 penetrating the PCa composite beam member 20 is reduced. However, the beam central portion 21 made of high-strength concrete can be made to enter the composite pillar 1.

  Furthermore, in this embodiment, the composite ramen structure 100 is spanned between a plurality of PCa composite column members 10 in which at least the column central portion 11 is made of PCa concrete, and the pair of composite columns 1, 1. At least the lower part of the outer peripheral part 22 has a PCa composite beam member 20 made of PCa concrete. Therefore, when constructing the PCa concrete of the beam outer peripheral portion 22 of the composite beam 2, the assembly of the formwork and the reinforcing bar and the concrete are carried out while supporting the portion protruding from the beam outer peripheral portion 22 of the beam central portion 21 of the composite beam 2. The PCa composite beam member 20 can be easily manufactured. In addition, because high-strength concrete is limited in terms of supply area and supply time, its use itself may be difficult depending on the location and process of the multi-layer building, but the central part 11 of the composite pillar 1 and the composite beam 2 Since the beam central portion 21 is composed of the PCa composite column member 10 and the PCa composite beam member 20, respectively, such a problem can be solved and quality control of high-strength concrete can be facilitated.

  Further, the PCa composite beam member 20 is arranged so that the protrusions 23 formed at both ends in the axial direction of the beam central portion 21 are arranged in the notches 13 of the PCa composite column member 10 and connected to the column central portion 11. . Thereby, the number of column main bars 16 penetrating the PCa composite beam member 20 can be reduced while the beam central portion 21 of the PCa composite beam member 20 is connected to the column central portion 11 of the PCa composite column member 10.

  In addition, since the beam central portion 21 of the PCa composite beam member 20 and the column central portion 11 of the PCa composite column member 10 are connected by the cotter joint 3, a load transmitted from the composite beam 2 to the composite column 1 is transmitted to the center of the beam. It can be reliably transmitted from the portion 21 to the column central portion 11, and the high compressive strength of the high-hardness concrete can be effectively used.

  This is the end of the description of the specific embodiments, but the present invention is not limited to these embodiments, and the specific shape, arrangement, quantity, angle, construction order, etc. of each element It can change suitably in the range which does not deviate from the meaning of invention.

  For example, as shown in FIG. 9A, the cross-sectional shape of the beam central portion 21 when the air vent portion 33 is not formed on the lower surface or the portion where the air vent portion 33 of the beam central portion 21 is not formed is the beam outer peripheral portion 22. It is good also as a rectangle substantially similar to the outline of. Moreover, it is good also considering the whole cross section of the beam center part 21, or the cross section of the part in which the air bleeding part 33 was formed as a shape like FIG.9 (B)-(H). In (B), the lower surface of the beam central portion 21 is a curved surface that is curved so as to advance upward as it goes outward. In (C), the lower surface of the beam central portion 21 is directed upward toward the outer side. It has an inclined surface that is inclined to advance. On the other hand, in (D) to (H), in addition to being curved or inclined so that the lower surface of the beam central portion 21 goes upward as it goes outward, the lower surface of the beam central portion 21 goes downward as it goes outward. Curved or inclined to advance.

  Alternatively, as shown in FIG. 10A, the beam central portion 21 may be divided into a plurality of parts in the left-right direction in the cross section. In this case, when forming the air bleeding portion 33, the lower surface of each beam central portion 21 may be curved or inclined so as to go upward as it goes to the outside of the PCa composite beam member 20.

  Moreover, in the said embodiment, although the concave strip 31 inclined to the left-right with respect to the perpendicular direction is formed in the side surface of the beam center part 21, the side surface of the beam center part 21 exhibits the uneven | corrugated shape which consists of a curve in a cross section. As long as this is the case, the same effect as described above can be obtained, and the present invention is not limited to the above configuration.

  In addition, all the elements of the composite pillar 1 structure according to the present invention and the elements of the construction procedure of the composite pillar 1 according to the present invention shown in the above embodiment are not necessarily essential, and can be appropriately selected.

DESCRIPTION OF SYMBOLS 1 Composite column 2 Composite beam 3 Cotter type joint 10 PCa composite column member 11 Column center part 12 Column outer peripheral part 20 PCa composite beam member 21 Beam central part 22 Beam outer peripheral part 23 Projection part 26 Beam main bar 27 Reinforcement 100 Composite ramen structure

Claims (5)

A beam central portion made of high-strength concrete having a predetermined water binder ratio and strength, and arranged in the cross-sectional central portion of the beam,
It is made of concrete having a high water binder ratio and low strength compared to the high-strength concrete, and has a beam outer peripheral portion arranged at the cross-sectional outer peripheral portion of the beam so as to cover the entire peripheral surface of the beam central portion,
The main beam and the reinforcing bar are arranged only on the outer periphery of the beam ,
In at least a part of the cross section, the lower surface of the central portion of the beam is inclined or curved upward as it goes outward from the center side . 2. The composite beam according to claim 1 , wherein a side surface of the central portion of the beam has an uneven shape including a curve in a cross section. A PCa composite beam member for constructing the composite beam according to claim 1 or 2 ,
The beam central portion is formed of PCa concrete made of the high-strength concrete,
At least the lower part of the outer periphery of the beam is formed of PCa concrete made of the concrete,
The PCa composite beam member, wherein the beam center portion protrudes from the beam outer peripheral portion at both axial ends. Columns and beams that are rigidly connected to each other, and a column central part and a beam central part arranged at the central part in the member cross section are made of high-strength concrete having a predetermined water binder ratio and strength, and the column central part and the beam A composite composed of concrete with a column outer periphery and a beam outer periphery arranged on the outer periphery of the member cross-section so as to cover the entire peripheral surface of the beam central portion and a water bonding material ratio higher than that of the high-strength concrete. Ramen structure,
A plurality of PCa column members formed of PCa concrete having at least the center portion of the column made of the high-strength concrete ;
Bridged pair of said post, and a PCa composite Beams least a lower portion of the formed by PCa concrete beam center portion is made of the high strength concrete and the beam outer periphery is formed by PCa concrete made from the concrete Have
The PCa composite beam member is formed so that the beam center portion protrudes from the outer periphery of the beam at both ends in the axial direction, and the protrusion portion of the beam center portion is located inside the column and the column center portion Composite ramen structure characterized by being arranged to connect. The composite ramen structure according to claim 4 , wherein the beam central portion of the PCa composite beam member and the column central portion of the PCa column member are connected by a cotter joint.

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