Beam joint construction

Abstract

The purpose is to suppress cracks that occur in reinforced concrete joints where reinforced concrete beams are joined and the main reinforcement bars of the beams are embedded, during an earthquake. [Solution] The beam joint structure comprises a reinforced concrete beam 10 having upper beam main reinforcement 12U and lower beam main reinforcement 12L, a joint portion 20J to which the reinforced concrete beam 10 is joined and to which upper end anchoring reinforcement 32U and lower end anchoring reinforcement 32L that constitute the ends of the upper end beam main reinforcement 12U or lower end beam main reinforcement 12L are embedded, and a non-frame-shaped U-shaped shear reinforcement 40 embedded in the joint portion 20J and positioned so as not to overlap with the upper end beam main reinforcement 12U and lower end beam main reinforcement 12L in a plan view.

Description

Technical Field

[0001] The present invention relates to a beam joint structure.

Background Art

[0002] A column-beam joint structure including a mechanical joint for connecting beam main reinforcements of a beam extending in a predetermined direction within a column-beam joint. The beam main reinforcements are arranged in at least two upper and lower stages. Shear reinforcement bars for reinforcing the column-beam joint include diagonal shear reinforcement bars arranged between the outermost column main reinforcements in a predetermined direction in the column and having a portion extending in the vertical direction. A column-beam joint structure is known (for example, see Patent Document 1).

[0003] Further, a precast concrete column-beam member formed integrally with a beam member, a column-beam joint portion, a lower column portion provided below the column-beam joint portion, an upper column portion provided above the column-beam joint portion, and a beam portion provided on the side of the column-beam joint portion. After arranging the column-beam member such that the end surface of the beam portion faces the end surface of the beam member, joining means inserted into the joint surface of the beam member or the joint surface of the beam portion to join the beam portion and the beam member. A joining structure of a precast concrete column-beam member is known (for example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0006] Considering the above facts, the present invention aims to suppress cracks that occur in reinforced concrete joints where reinforced concrete beams are joined and the main reinforcement bars of the beams are embedded, during an earthquake. [Means for solving the problem]

[0007] The beam joint structure according to claim 1 comprises: a reinforced concrete beam having beam main reinforcement; a reinforced concrete joint portion to which the reinforced concrete beam is joined and to which the beam main reinforcement is embedded; and a non-frame-shaped non-frame-shaped shear reinforcement embedded in the reinforced concrete joint portion and positioned so as not to overlap with the beam main reinforcement in a plan view.

[0008] According to the beam joint structure of claim 1, the reinforced concrete beam has main beam reinforcement. This reinforced concrete beam is joined to a reinforced concrete joint. The main beam reinforcement of the reinforced concrete beam is embedded in the reinforced concrete joint. In addition, non-frame-shaped non-frame-shaped shear reinforcement is embedded in the reinforced concrete joint.

[0009] Here, the non-frame shear reinforcement is positioned so as not to overlap with the main beam reinforcement in a plan view. In other words, since the non-frame shear reinforcement does not interfere with the main beam reinforcement, the degree of freedom in the placement of the reinforcement is increased compared to frame shear reinforcement (hereinafter referred to as "frame shear reinforcement") in a plan view.

[0010] Therefore, in this invention, by embedding non-frame-shaped shear reinforcement bars in the reinforced concrete joint, cracks that occur in the reinforced concrete joint during an earthquake can be efficiently suppressed.

[0011] The beam joint structure according to claim 2 is the beam joint structure according to claim 1, wherein the reinforced concrete beam is joined to one side of the reinforced concrete joint, the end of the main reinforcement of the beam is embedded in the reinforced concrete joint, and the non-frame shear reinforcement is embedded along the outer circumference of the reinforced concrete joint, forming a U-shape with the reinforced concrete beam side open in a plan view.

[0012] According to the beam joint structure of claim 2, the reinforced concrete beam is joined to one side of the reinforced concrete joint, and the ends of the main beam reinforcement are embedded in the reinforced concrete joint. In addition, the non-frame shear reinforcement is embedded along the outer circumference of the reinforced concrete joint, forming a U-shape with the reinforced concrete beam side open in a plan view.

[0013] In this case, when a reinforced concrete beam is joined to one side of a reinforced concrete joint, there is a possibility that cracks or other damage may occur in the part of the reinforced concrete joint opposite to the reinforced concrete beam during an earthquake.

[0014] In contrast, the non-frame-shaped shear reinforcement of the present invention is embedded along the outer periphery of the reinforced concrete joint and, in plan view, forms a U-shape with the reinforced concrete beam side open. By reinforcing the reinforced concrete joint with this non-frame-shaped shear reinforcement, cracks that occur in the part of the reinforced concrete joint opposite to the reinforced concrete beam during an earthquake can be efficiently suppressed.

[0015] The beam joint structure according to claim 3 is the beam joint structure according to claim 2, wherein the non-frame shear reinforcement is arranged in a position that overlaps with the main beam reinforcement, or around the main beam reinforcement, when viewed from the side of the reinforced concrete beam.

[0016] According to the beam joint structure of claim 3, the non-frame shear reinforcement is positioned in a location that overlaps with the main beam reinforcement, or around the main beam reinforcement, when viewed from the side of the reinforced concrete beam.

[0017] Here, because the frame-shaped shear reinforcement is prone to interference with the main beam reinforcement embedded in the reinforced concrete joint, it is difficult to position it in a location that overlaps with the main beam reinforcement or around the main beam reinforcement when viewed from the side of the reinforced concrete beam.

[0018] In contrast, the non-frame-shaped shear reinforcement of the present invention can be positioned in a location that overlaps with the main beam reinforcement, or around the main beam reinforcement, when viewed from the side of the reinforced concrete beam. Therefore, the present invention can efficiently suppress cracks that occur on the side opposite to the reinforced concrete beam during an earthquake.

[0019] The beam joint structure according to claim 4 is the beam joint structure according to claim 2 or claim 3, further comprising a mechanical joint embedded in the reinforced concrete beam side of the reinforced concrete joint and connected to the main reinforcement of the beam.

[0020] According to the beam joint structure of claim 4, a mechanical joint is embedded in the reinforced concrete beam side of the reinforced concrete joint. The mechanical joint is connected to the main reinforcement of the beam.

[0021] In this invention, as described above, a mechanical joint is embedded in the reinforced concrete beam side of the reinforced concrete joint. In this case, the mechanical joint functions as a reinforcing member that reinforces the reinforced concrete beam side of the reinforced concrete joint. Therefore, cracks and other damage that occur in the reinforced concrete beam side of the reinforced concrete joint during an earthquake are suppressed.

[0022] As a result, cracks and other damage are more likely to occur in the reinforced concrete joint on the side opposite to the reinforced concrete beam. In such cases, the present invention is particularly effective, as embedding non-frame shear reinforcement bars in the reinforced concrete joint can efficiently suppress cracks that occur in the reinforced concrete joint on the side opposite to the reinforced concrete beam during an earthquake. [Effects of the Invention]

[0023] As described above, according to the present invention, in a reinforced concrete joint portion where a reinforced concrete beam is joined and main beam reinforcement bars are embedded, it is possible to suppress cracks generated in the reinforced concrete joint portion during an earthquake.

Brief Description of the Drawings

[0024] [Figure 1] It is a vertical cross-sectional view showing a reinforced concrete beam and a reinforced concrete column to which a beam joint structure according to an embodiment is applied. [Figure 2] It is a cross-sectional view taken along line 2-2 of FIG. 1. [Figure 3] It is a cross-sectional view taken along line 3-3 of FIG. 1. [Figure 4] It is a vertical cross-sectional view showing a reinforced concrete beam and a reinforced concrete column to which a beam joint structure according to a comparative example is applied. [Figure 5] It is a vertical cross-sectional view showing a reinforced concrete beam and a reinforced concrete column to which a modified example of a beam joint structure according to an embodiment is applied. [Figure 6] It is a cross-sectional view taken along line 6-6 of FIG. 5. [Figure 7] It is a vertical cross-sectional view showing a reinforced concrete beam and a reinforced concrete column to which a modified example of a beam joint structure according to an embodiment is applied. [Figure 8] It is a cross-sectional view taken along line 8-8 of FIG. 7.

Modes for Carrying Out the Invention

[0025] Hereinafter, an embodiment will be described with reference to the drawings.

[0026] (Beam Joint Structure) In FIG. 1, a reinforced concrete beam 10 and a reinforced concrete column 20 to which the beam joint structure according to the present embodiment is applied are shown. As an example, the reinforced concrete beam 10 is joined to one side of the joint portion 20J of the reinforced concrete column 20. That is, the reinforced concrete beam 10 and the reinforced concrete column 20 are joined in a so-called T shape in a side view of the reinforced concrete beam 10.

[0027] Note that the joint section 20J of the reinforced concrete column 20 is an example of a reinforced concrete joint section.

[0028] (Reinforced concrete beam) The reinforced concrete beam 10 is constructed of reinforced concrete. This reinforced concrete beam 10 has multiple upper beam main reinforcements 12U, multiple lower beam main reinforcements 12L, and multiple shear reinforcements 14 embedded within it. Note that the upper beam main reinforcements 12U and lower beam main reinforcements 12L are examples of beam main reinforcements.

[0029] Multiple upper beam main reinforcement bars 12U are arranged along the material axis of the reinforced concrete beam 10. Furthermore, these multiple upper beam main reinforcement bars 12U are arranged in two layers on the upper end side of the reinforced concrete beam 10, and are spaced apart in the beam width direction. These upper beam main reinforcement bars 12U protrude from the end face of the reinforced concrete beam 10 and are embedded in the joint portion 20J of the reinforced concrete column 20.

[0030] Multiple lower beam main reinforcement bars 12L are arranged along the material axis of the reinforced concrete beam 10. Furthermore, these multiple lower beam main reinforcement bars 12L are arranged in two layers on the lower end side of the reinforced concrete beam 10, and are spaced apart in the beam width direction. These lower beam main reinforcement bars 12L protrude from the end face of the reinforced concrete beam 10 and are embedded in the joint portion 20J of the reinforced concrete column 20.

[0031] Furthermore, the main reinforcement bars 12U for the upper beam and 12L for the lower beam are not limited to two layers of reinforcement; they may be one layer or three or more layers. Also, the number and arrangement of the main reinforcement bars 12U for the upper beam and 12L for the lower beam can be changed as appropriate.

[0032] (Reinforced concrete column) The reinforced concrete column 20 is made of reinforced concrete. In this embodiment, the reinforced concrete column 20 is made of precast concrete as an example. This reinforced concrete column 20 is formed in a rectangular column shape and has four sides 20S1, 20S2, 20S3, and 20S4 (see Figure 2).

[0033] Multiple main reinforcement bars 22 and multiple frame-shaped shear reinforcement bars 24 are embedded in the reinforced concrete column 20. The multiple main reinforcement bars 22 are arranged along the material axis direction of the reinforced concrete column 20. The multiple frame-shaped shear reinforcement bars 24 are arranged at intervals along the material axis direction of the reinforced concrete column 20.

[0034] As shown in Figure 2, multiple main column reinforcements 22 are arranged around the outer periphery of a reinforced concrete column 20, spaced apart in the circumferential direction of the column. Multiple frame-shaped shear reinforcements 24 are placed around the outer periphery of these main column reinforcements 22.

[0035] Multiple frame-shaped shear reinforcement bars 24 are bent into a rectangular frame shape in a plan view. Furthermore, multiple frame-shaped shear reinforcement bars 24 are embedded around the outer perimeter of the reinforced concrete column 20, surrounding multiple column main reinforcement bars 22. These frame-shaped shear reinforcement bars 24 restrain the multiple column main reinforcement bars 22.

[0036] (Joint section) As shown in Figure 1, the reinforced concrete column 20 has a joint section 20J to which the end of the reinforced concrete beam 10 is joined. In addition to the aforementioned multiple main column reinforcements 22 and multiple frame-shaped shear reinforcements 24, multiple upper mechanical joints 30U, multiple lower mechanical joints 30L, multiple upper anchoring bars 32U, and multiple lower anchoring bars 32L are embedded in the joint section 20J.

[0037] Note that the upper mechanical joint 30U and the lower mechanical joint 30L are examples of mechanical joints. Also, the upper anchoring reinforcement 32U and the lower anchoring reinforcement 32L are examples of anchoring reinforcement.

[0038] Multiple upper mechanical joints 30U are used to connect multiple upper beam main reinforcement bars 12U protruding from the end face of the reinforced concrete beam 10 to upper anchoring reinforcement bars 32U embedded in the joint section 20J. These upper mechanical joints 30U are provided in the joint section 20J in correspondence with the multiple upper beam main reinforcement bars 12U.

[0039] Similarly, the multiple lower mechanical joints 30L are joints that connect the multiple lower beam main reinforcement bars 12L protruding from the end face of the reinforced concrete beam 10 to the lower anchorage reinforcement bars 32L embedded in the joint section 20J. These lower mechanical joints 30L are provided in the joint section 20J in correspondence with the multiple lower beam main reinforcement bars 12L.

[0040] Since the upper mechanical joint 30U and the lower mechanical joint 30L have similar configurations, the configuration of the upper mechanical joint 30U will be described below, and the description of the configuration of the lower mechanical joint 30L will be omitted as appropriate.

[0041] Multiple upper mechanical joints 30U are formed in a cylindrical (sleeve) shape, and are arranged with their axial direction in line with the material axis direction of the reinforced concrete beam 10, and are spaced apart in the beam width direction of the reinforced concrete beam 10.

[0042] Each upper mechanical joint 30U is embedded in the reinforced concrete beam 10 side of the joint 20J, with one end opening into the side surface 20S1 of the joint 20J. Furthermore, one end of each upper mechanical joint 30U is substantially flush with the side surface 20S1 of the joint 20J. The upper beam main reinforcement 12U, which protrudes from the end face of the reinforced concrete beam 10, is connected to one end of this upper mechanical joint 30U.

[0043] On the other hand, one end of the upper end anchoring reinforcement 32U is connected to the other end of each upper end mechanical joint 30U. Each upper end anchoring reinforcement 32U is a reinforcing bar that anchors the upper end mechanical joint 30U, to which the upper end beam main reinforcement 12U is connected, to the joint portion 20J, and constitutes the end of the upper end beam main reinforcement 12U.

[0044] Similarly, one end of the lower end anchoring reinforcement bar 32L is connected to the other end of each lower end mechanical joint 30L. Each lower end anchoring reinforcement bar 32L is a reinforcing bar that anchors the lower end mechanical joint 30L, to which the lower end beam main reinforcement bar 12L is connected, to the joint portion 20J, and constitutes the end portion of the lower end beam main reinforcement bar 12L.

[0045] Since the upper anchoring muscle 32U and the lower anchoring muscle 32L have similar configurations, the configuration of the upper anchoring muscle 32U will be described below, and the description of the configuration of the lower anchoring muscle 32L will be omitted as appropriate.

[0046] The upper anchoring reinforcement bar 32U is formed from a straight reinforcing bar, with an anchoring body 34 attached to the other end. By embedding this anchoring body 34 in the joint 20J, the anchoring strength of the upper anchoring reinforcement bar 32U to the joint 20J is increased. The upper anchoring reinforcement bar 32U is also connected to the upper beam main reinforcement bar 12U via an upper mechanical joint 30U.

[0047] The anchoring body 34 may be provided on the upper anchoring bar 32U or the lower anchoring bar 32L as needed, and can be omitted as appropriate. Alternatively, instead of providing the anchoring body 34 on the upper anchoring bar 32U or the lower anchoring bar 32L, the upper anchoring bar 32U or the lower anchoring bar 32L may be anchored in a straight line or in a bent position. Furthermore, various mechanical joints such as screw-in type or insert-type (sleeve type) can be used for the upper mechanical joint 30U and the lower mechanical joint 30L.

[0048] (U-shaped shear reinforcement) As shown in Figures 1 and 3, multiple U-shaped shear reinforcements 40 are embedded in the joint portion 20J of the reinforced concrete column 20. The U-shaped shear reinforcements 40 primarily serve as shear reinforcements to reinforce the portion of the joint portion 20J opposite to the reinforced concrete beam 10. The U-shaped shear reinforcements 40 are an example of non-frame-shaped shear reinforcements.

[0049] As shown in Figure 3, the U-shaped shear reinforcement bars 40 form a U-shape (C-shape) in plan view, with the reinforced concrete beam 10 side being open. The U-shaped shear reinforcement bars 40 are embedded in the outer periphery of the joint 20J, surrounding multiple column main reinforcement bars 22 along the three sides 20S2, 20S3, and 20S4 (three sides) of the joint 20J, excluding the side 20S1 of the joint 20J to which the reinforced concrete beam 10 is joined.

[0050] Inside the U-shaped shear reinforcement bars 40, upper anchorage bars 32U or lower anchorage bars 32L, which constitute the ends of the upper beam main reinforcement bars 12U, are arranged. In addition, hooks 40F are provided at both ends of the opening side of the U-shaped shear reinforcement bars 40. Each hook 40F is, for example, a 135-degree hook and is hooked onto the column main reinforcement bars 22 embedded in the corner of the joint portion 20J on the reinforced concrete beam 10 side.

[0051] Note that the hook 40F is not limited to a 135-degree hook; for example, a 180-degree hook or a 90-degree hook may also be used. Furthermore, the hook 40F may be provided on the U-shaped shear reinforcement bar 40 as needed, and can be omitted as appropriate.

[0052] As shown in Figure 1, the U-shaped shear reinforcement bars 40 are positioned in a side view of the reinforced concrete beam 10 so as to overlap with the upper anchorage bars 32U that constitute the end of the upper main beam reinforcement bars 12U. More specifically, the U-shaped shear reinforcement bars 40 are positioned in a side view of the reinforced concrete beam 10 so as to overlap with the upper main beam reinforcement bars 12U, the upper mechanical joint 30U, and the upper anchorage bars 32U.

[0053] Similarly, the U-shaped shear reinforcement bars 40 are positioned in a location that overlaps with the lower anchorage bars 32L that constitute the end of the lower main beam reinforcement bars 12L when viewed from the side of the reinforced concrete beam 10. More specifically, the U-shaped shear reinforcement bars 40 are positioned in a location that overlaps with the lower main beam reinforcement bars 12L, the lower mechanical joint 30L, and the lower anchorage bars 32L when viewed from the side of the reinforced concrete beam 10.

[0054] (action) Next, the operation of this embodiment will be described.

[0055] First, a comparative example will be described. Figure 4 shows a reinforced concrete beam 10 and a reinforced concrete column 20 to which the beam joint structure according to the comparative example is applied. The reinforced concrete column 20 according to the comparative example differs from the reinforced concrete column 20 according to this embodiment in that a U-shaped shear reinforcement bar 40 is not embedded in the joint portion 20J.

[0056] As shown in Figure 4, in the joint portion 20J of the reinforced concrete column 20 in the comparative example, the frame-shaped shear reinforcement bars 24 are not placed in a position that overlaps with the upper end anchorage bars 32U that constitute the end of the upper end main reinforcement bars 12U, as seen in a side view of the reinforced concrete beam 10, nor around the upper end anchorage bars 32U. This is because the frame-shaped shear reinforcement bars 24 would interfere with the upper end main reinforcement bars 12U.

[0057] Similarly, in the joint portion 20J of the reinforced concrete column 20 in the comparative example, the frame-shaped shear reinforcement bars 24 are not placed in the position where they overlap with the lower end anchorage bars 32L that constitute the end of the lower end main reinforcement bars 12L, as seen in a side view of the reinforced concrete beam 10, nor around the lower end anchorage bars 32L. This is because the frame-shaped shear reinforcement bars 24 would interfere with the lower end main reinforcement bars 12L.

[0058] In this case, if, for example, a bending moment M acts on the reinforced concrete beam 10 during an earthquake, cracks V are likely to occur at the joint portion 20J of the reinforced concrete column 20 on the side opposite to the reinforced concrete beam 10.

[0059] In contrast, in this embodiment, as shown in Figure 1, U-shaped shear reinforcement bars 40 are embedded around the outer periphery of the joint portion 20J of the reinforced concrete column 20.

[0060] As shown in Figure 3, the U-shaped shear reinforcement bars 40 form a U-shape with the reinforced concrete beam 10 side open in a plan view and are embedded along the outer circumference of the joint 20J. Therefore, the U-shaped shear reinforcement bars 40 are less likely to interfere with the upper beam main reinforcement bars 12U and the lower beam main reinforcement bars 12L, thus providing greater flexibility in the placement of the reinforcement bars compared to the frame-shaped shear reinforcement bars 24.

[0061] Therefore, in this embodiment, by embedding U-shaped shear reinforcement bars 40 in the joint portion 20J, cracks that occur in the portion of the joint portion 20J opposite to the reinforced concrete beam 10 during an earthquake can be efficiently suppressed.

[0062] Furthermore, as shown in Figure 1, in this embodiment, the U-shaped shear reinforcement bars 40 are positioned in a location that overlaps with the upper anchorage bars 32U that constitute the end of the upper main reinforcement bars 12U, or in a location that overlaps with the lower anchorage bars 32L that constitute the end of the lower main reinforcement bars 12L, when viewed from the side of the reinforced concrete beam 10.

[0063] Here, as mentioned above, the frame-shaped shear reinforcement bars 24 are prone to interference with the upper beam main reinforcement bars 12U or lower beam main reinforcement bars 12L embedded in the joint portion 20J. Therefore, it is difficult to position the frame-shaped shear reinforcement bars 24 in a position that overlaps with the upper beam main reinforcement bars 12U or lower beam main reinforcement bars 12L, or around the upper beam main reinforcement bars 12U or lower beam main reinforcement bars 12L, when viewed from the side of the reinforced concrete beam 10.

[0064] In contrast, the U-shaped shear reinforcement bars 40 of this embodiment can be positioned in a location that overlaps with the upper beam main reinforcement bars 12U or the lower beam main reinforcement bars 12L when viewed from the side of the reinforced concrete beam 10, or around the upper beam main reinforcement bars 12U or the lower beam main reinforcement bars 12L. Therefore, in this embodiment, cracks V that occur on the side opposite to the reinforced concrete beam 10 can be efficiently suppressed during an earthquake.

[0065] Furthermore, in this embodiment, multiple upper mechanical joints 30U and lower mechanical joints 30L are embedded in the reinforced concrete beam 10 side of the joint portion 20J of the reinforced concrete column 20. In this case, the upper mechanical joints 30U and lower mechanical joints 30L function as reinforcing members that reinforce the reinforced concrete beam 10 side of the joint portion 20J. Therefore, cracks and other damage that occur in the reinforced concrete beam 10 side of the joint portion 20J are suppressed during an earthquake.

[0066] As a result, cracks V (see Figure 4) and the like are more likely to occur in the joint 20J on the side opposite to the reinforced concrete beam 10. In such cases, this embodiment is particularly effective, as by embedding U-shaped shear reinforcement bars 40 in the joint 20J, cracks that occur in the joint 20J on the side opposite to the reinforced concrete beam 10 can be efficiently suppressed during an earthquake.

[0067] (modified version) Next, a modified example of the above embodiment will be described.

[0068] In the above embodiment, as shown in Figure 3, the hook 40F of the U-shaped shear reinforcement bar 40 is hooked onto the main column reinforcement bar 22 embedded in the corner on the reinforced concrete beam 10 side of the joint portion 20J of the reinforced concrete column 20. However, the main column reinforcement bar 22 to which the hook 40F of the U-shaped shear reinforcement bar 40 is hooked can be changed as appropriate.

[0069] For example, as shown in the modified example in Figure 5, assuming that cracks occur along the diagonals L1 and L2 of the joint portion 20J of the reinforced concrete column 20 in a side view of the reinforced concrete beam 10, by arranging U-shaped shear reinforcement bars 42 so as to cross the diagonals L1 and L2 in the side view, cracks along the diagonals L1 and L2 can be suppressed during an earthquake.

[0070] Therefore, the hooks 42F of the U-shaped shear reinforcement bars 42 can be hooked onto the main column reinforcement bars 22 that are arranged in the center of the width direction on the side surfaces 20S2 and 20S4 of the joint portion 20J, as shown in Figure 6.

[0071] Furthermore, the diagonal line L1 shown in Figure 5 corresponds to the cracks that occur at the joint 20J when a bending moment M is applied to the reinforced concrete beam 10, as shown in Figure 4, and the diagonal line L2 corresponds to the cracks that occur at the joint 20J when a bending moment opposite to the bending moment M shown in Figure 4 is applied to the reinforced concrete beam 10. In addition, the U-shaped shear reinforcement 42 is an example of non-frame-shaped shear reinforcement.

[0072] Furthermore, in the above embodiment, the U-shaped shear reinforcement bars 40 are positioned in a location that overlaps with the upper beam main reinforcement bars 12U (upper anchoring bars 32U) or the lower beam main reinforcement bars 12L (lower anchoring bars 32L) when viewed from the side of the reinforced concrete beam 10. However, the U-shaped shear reinforcement bars 40 are not limited to being positioned in a location that overlaps with the upper beam main reinforcement bars 12U (upper anchoring bars 32U) or the lower beam main reinforcement bars 12L (lower anchoring bars 32L) when viewed from the side of the reinforced concrete beam 10. For example, they may be positioned around (above or below) the upper beam main reinforcement bars 12U (upper anchoring bars 32U) or the lower beam main reinforcement bars 12L (lower anchoring bars 32L).

[0073] Furthermore, the U-shaped shear reinforcement bars 40 can also be placed on both the upper and lower sides of the upper beam main reinforcement bars 12U (upper anchoring bars 32U) or the lower beam main reinforcement bars 12L (lower anchoring bars 32L) when viewed from the side of the reinforced concrete beam 10.

[0074] Furthermore, in the above embodiment, a reinforced concrete beam 10 is joined to one side of the joint portion 20J of the reinforced concrete column 20. However, as shown in the modified examples in Figures 7 and 8, a pair of reinforced concrete beams 10 may be joined to both sides of the joint portion 20J of the reinforced concrete column 20.

[0075] Specifically, a pair of reinforced concrete beams 10 are joined to each other via a joint portion 20J of a reinforced concrete column 20. The upper beam main reinforcement 12U and lower beam main reinforcement 12L of this pair of reinforced concrete beams 10 penetrate the joint portion 20J and are embedded across the pair of reinforced concrete beams 10.

[0076] In the modified example shown in Figure 8, multiple linear shear reinforcement bars 50 are embedded in the joint portion 20J of the reinforced concrete column 20. Note that the linear shear reinforcement bars 50 are an example of non-frame shear reinforcement bars.

[0077] Each linear shear reinforcement bar 50 is formed by linear reinforcement bars. Furthermore, each linear shear reinforcement bar 50 is arranged along the material axis of the pair of reinforced concrete beams 10, and is positioned so as not to overlap with the upper beam main reinforcement bars 12U and the lower beam main reinforcement bars 12L in a plan view.

[0078] Specifically, as shown in Figure 8, the linear shear reinforcement bars 50 are arranged in a plan view on both sides of multiple upper beam main reinforcement bars 12U (or lower beam main reinforcement bars 12L), and between adjacent upper beam main reinforcement bars 12U (or lower beam main reinforcement bars 12L).

[0079] Each linear shear reinforcement bar 50 is provided with a hook 50F at both ends. Each hook 50F is, for example, a 135-degree hook and is hooked onto the main column reinforcement bar 22 embedded in the outer circumference of the joint 20J.

[0080] Here, as mentioned above, the frame-shaped shear reinforcement bars 24 are prone to interference with the upper beam main reinforcement bars 12U or lower beam main reinforcement bars 12L embedded in the joint portion 20J. Therefore, it is difficult to position the frame-shaped shear reinforcement bars 24 in a position that overlaps with the upper beam main reinforcement bars 12U or lower beam main reinforcement bars 12L, or around the upper beam main reinforcement bars 12U or lower beam main reinforcement bars 12L, when viewed from the side of the reinforced concrete beam 10.

[0081] In contrast, in this modified example, as described above, multiple linear shear reinforcements 50 are positioned in a location that does not overlap with the upper beam main reinforcement 12U and the lower beam main reinforcement 12L in a plan view.

[0082] As a result, as shown in Figure 7, the linear shear reinforcement bars 50 can be placed in a position that overlaps with the upper beam main reinforcement bars 12U in a side view of the reinforced concrete beam 10. Similarly, the linear shear reinforcement bars 50 can be placed in a position that overlaps with the lower beam main reinforcement bars 12L in a side view of the reinforced concrete beam 10. Therefore, cracks that occur in the joint 20J during an earthquake can be efficiently suppressed.

[0083] Furthermore, the linear shear reinforcement bars 50 are not limited to being positioned in a location that overlaps with the upper beam main reinforcement bars 12U or the lower beam main reinforcement bars 12L when viewed from the side of the reinforced concrete beam 10. For example, they may be placed around (above or below) the upper beam main reinforcement bars 12U or the lower beam main reinforcement bars 12L. In addition, the linear shear reinforcement bars 50 can be placed on both the upper and lower sides of the upper beam main reinforcement bars 12U or the lower beam main reinforcement bars 12L when viewed from the side of the reinforced concrete beam 10.

[0084] Furthermore, the linear shear reinforcement bars 50 may be applied to the joint portion 20J of a reinforced concrete column 20 to which a reinforced concrete beam 10 is joined on one side, for example, as shown in Figure 3.

[0085] Furthermore, in the above embodiment, since the joint portion 20J of the reinforced concrete column 20 is formed by precast concrete, the upper mechanical joint 30U and the lower mechanical joint 30L are embedded in the joint portion 20J. However, for example, if the reinforced concrete column 20 is formed by cast-in-place concrete, the upper mechanical joint 30U and the lower mechanical joint 30L may not be embedded in the joint portion 20J, and instead, the upper beam main reinforcement 12U and the lower beam main reinforcement 12L may be embedded. In this case, the anchorage length of the upper beam main reinforcement 12U and the lower beam main reinforcement 12L relative to the joint portion 20J can be appropriately changed.

[0086] Furthermore, in the above embodiment, the reinforced concrete beam 10 and the reinforced concrete column 20 are joined in a so-called T-shape when viewed from the side of the reinforced concrete beam 10. However, the reinforced concrete beam 10 and the reinforced concrete column 20 are not limited to a so-called T-shape when viewed from the side of the reinforced concrete beam 10; for example, they may be joined in a cross shape, or at the top floor of the structure, they may be joined in a so-called L-shape or T-shape.

[0087] Furthermore, in this embodiment, the reinforced concrete beam 10 joined to one side of the joint portion 20J of the reinforced concrete column 20 means that, in a side view of the reinforced concrete beam 10, no reinforced concrete beam having upper or lower main beam reinforcement at the same height as the upper or lower main beam reinforcement 12U or lower main beam reinforcement 12L is joined to the side opposite to the reinforced concrete beam 10 at the joint portion 20J. Therefore, for example, in a side view of the reinforced concrete beam 10, a reinforced concrete beam with a different height from the reinforced concrete beam 10 or a reinforced concrete beam with a different beam depth may be joined to the side opposite to the reinforced concrete beam 10 at the joint portion 20J.

[0088] Furthermore, a steel-reinforced concrete beam (hereinafter referred to as a "steel-reinforced concrete orthogonal beam") may be joined to the joint portion 20J of the reinforced concrete column 20 in a direction perpendicular to the reinforced concrete beam 10. In this case, the upper beam main reinforcement 12U and lower beam main reinforcement 12L of the reinforced concrete beam 10 and the upper beam main reinforcement and lower beam main reinforcement of the steel-reinforced concrete orthogonal beam may be arranged, for example, with an upward or downward offset to avoid interference.

[0089] Furthermore, in the above embodiment, the reinforced concrete joint is the joint 20J of the reinforced concrete column 20. However, the reinforced concrete joint is not limited to the joint 20J of the reinforced concrete column 20, but may also be, for example, the joint of a reinforced concrete foundation.

[0090] Although one embodiment of the present invention has been described above, the present invention is not limited to these embodiments, and various modifications may be used in appropriate combinations with one embodiment, and of course, the invention can be implemented in various forms without departing from the spirit of the present invention. [Explanation of Symbols]

[0091] 10 Reinforced concrete beam 12U Top end beam main reinforcement (beam main reinforcement) 12L Lower end beam main reinforcement (beam main reinforcement) 20 Reinforced concrete columns 20J Joint section (reinforced concrete joint section) 30U Upper end mechanical coupling (mechanical coupling) 30L Lower Mechanical Connector (Mechanical Connector) 40. U-shaped shear reinforcement bars (non-frame-shaped shear reinforcement bars) 42. U-shaped shear reinforcement bars (non-frame-shaped shear reinforcement bars) 50. Linear shear reinforcement bars (non-frame shear reinforcement bars)

Claims

1. A reinforced concrete beam having main reinforcement, The reinforced concrete joint portion to which the reinforced concrete beams are joined and to which the main reinforcement of the beams is embedded, A non-frame-shaped shear reinforcement bar is embedded in the reinforced concrete joint and positioned in a location that does not overlap with the main reinforcement bars of the beam in a plan view, A beam joint structure equipped with this feature.

2. The reinforced concrete beam is joined to one side of the reinforced concrete joint, and the end of the main reinforcement of the beam is embedded in the reinforced concrete joint. The non-frame-shaped shear reinforcement is embedded along the outer periphery of the reinforced concrete joint and, in plan view, forms a U-shape with the reinforced concrete beam side open. The beam joint structure according to claim 1.

3. The non-frame shear reinforcement is positioned in a location that overlaps with the main beam reinforcement, or around the main beam reinforcement, when viewed from the side of the reinforced concrete beam. The beam joint structure according to claim 2.

4. The reinforced concrete joint section includes a mechanical joint embedded in the reinforced concrete beam side and connected to the main reinforcement of the beam. The beam joint structure according to claim 2 or claim 3.

Images