Column-beam structure

Abstract

The aim is to make structural members reusable. [Solution] The column-beam frame structure comprises a precast joint member 30 having a lower precast column 20L, a concrete joint portion 40 that is detachably joined to the lower precast column 20L, and a steel beam bracket 50 that is embedded in the concrete joint portion 40 and whose end protrudes from the side surface of the concrete joint portion 40.

Description

Technical Field

[0001] The present invention relates to a column-beam frame structure.

Background Art

[0002] There is known a precast concrete joint in which a precast concrete column and a precast concrete joint with a steel beam are joined (see, for example, Patent Document 1).

[0003] Also, a steel beam structure that plasticizes a steel beam during an earthquake is known at a position away from the joint between the column and the steel beam (see, for example, Patent Documents 2 and 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, structural members such as columns and beams are generally discarded as industrial waste at the time of demolition.

[0006] However, in recent years, from the perspective of the global environment and the like, reduction of industrial waste is required, and there is a desire to reuse (recycle) structural members.

[0007] In consideration of the above facts, an object of the present invention is to make structural members reusable.

Means for Solving the Problems

[0008] The column-beam frame structure according to claim 1 comprises a concrete column, a concrete joint portion detachably joined to the concrete column, and a precast joint member having a steel beam bracket embedded in the concrete joint portion and having an end portion protruding from the side surface of the concrete joint portion.

[0009] The column-beam frame structure according to claim 1 comprises a concrete column and a precast joint member. The precast joint member has a concrete joint portion and a steel beam bracket. The concrete joint portion is detachably joined to the concrete column.

[0010] The steel beam bracket is embedded in the concrete joint, with its end protruding from the side of the concrete joint. A beam member, for example, is joined to the end of this steel beam bracket.

[0011] As mentioned above, the concrete joint portion of the precast joint member is detachably joined to the concrete column. Therefore, the precast joint member can be removed from the concrete column during demolition. This allows the precast joint member to be reused.

[0012] Thus, the present invention makes it possible to reuse precast joint members as structural members.

[0013] The column-beam frame structure according to claim 2 is the column-beam frame structure according to claim 1, further comprising: a steel beam member whose end is joined to the end of the steel beam bracket; and a bracket non-yielding means provided on at least one of the steel beam bracket and the steel beam member, which yields the steel beam member or slides the joint between the steel beam bracket and the steel beam member before the steel beam bracket yields.

[0014] According to the column-beam frame structure of claim 2, the end of the steel beam member is joined to the end of the steel beam bracket. At least one of these steel beam brackets and steel beam members is provided with a bracket non-yielding means. The bracket non-yielding means causes the steel beam member to yield or the joint between the steel beam bracket and the steel beam member to slide before the steel beam bracket yields.

[0015] By providing a bracket non-yielding mechanism on at least one of the steel beam bracket and the steel beam member in this manner, damage to the steel beam bracket during an earthquake is suppressed. Therefore, it becomes easier to reuse precast joint members.

[0016] The column-beam frame structure according to claim 3 is a column-beam frame structure according to claim 1 or claim 2, comprising: a PC steel member extending from the upper surface of the concrete column and slidably penetrating the concrete joint portion in the vertical direction; and a fixing device that fixes the tensioned PC steel member to the upper surface of the concrete joint portion and press-fits the lower surface of the concrete joint portion and the upper surface of the concrete column via a joint material.

[0017] According to the column-beam frame structure of claim 3, the PC steel extends from the upper surface of the concrete column and slides vertically through the concrete joint portion of the precast joint member. The anchoring device fixes the tensioned PC steel to the upper surface of the concrete joint portion and press-fits the lower surface of the concrete joint portion and the upper surface of the concrete column via a joint material.

[0018] By using PC steel materials and anchoring devices in this way, concrete columns and precast joint members can be easily and detachably joined together.

[0019] The column-beam frame structure according to claim 4 is the column-beam frame structure according to claim 3, wherein the PC steel members are not anchored to the upper surface of the concrete column.

[0020] According to the column-beam framework structure according to claim 4, the PC steel material is not fixed to the upper surface of the concrete column. That is, the PC steel material is not fixed to the upper surface of the concrete column, but is fixed to the upper surface of the concrete joint portion of the precast joint member.

[0021] Thereby, in the present invention, the workability is improved as compared with the case where the PC steel material is fixed to the upper surface of the concrete column and the upper surface of the concrete joint portion, respectively.

Effect of the Invention

[0022] As described above, according to the present invention, the structural members can be made reusable.

Brief Description of the Drawings

[0023] [Figure 1] It is an elevation view showing a lower precast column, an upper precast column, and a precast joint member to which the column-beam framework structure according to the first embodiment is applied. [Figure 2] It is a sectional view taken along line 2-2 of FIG. 1. [Figure 3] It is an elevation view showing the construction process of the column-beam framework structure according to the first embodiment. [Figure 4] It is an elevation view showing the construction process of the column-beam framework structure according to the first embodiment. [Figure 5] (A) is a plan view showing a steel beam member in the column-beam framework structure according to the second embodiment, and (B) is a side view of the steel beam member shown in FIG. 5(A). [Figure 6] (A) and (B) are a plan view and a side view respectively corresponding to FIGS. 5(A) and 5(B) showing a steel beam member in a modified example of the column-beam framework structure according to the second embodiment. [Figure 7] (A) and (B) are a plan view and a side view respectively corresponding to FIGS. 5(A) and 5(B) showing a steel beam member in a modified example of the column-beam framework structure according to the second embodiment. [Figure 8](A) and (B) are a plan view and a side view, respectively, of the steel beam members in a modified example of the column-beam frame structure according to the second embodiment, as shown in Figures 5(A) and 5(B). [Figure 9] (A) and (B) are a plan view and a side view, respectively, of the steel beam members in a modified example of the column-beam frame structure according to the second embodiment, as shown in Figures 5(A) and 5(B). [Figure 10] (A) and (B) are a plan view and a side view, respectively, of the steel beam members in a modified example of the column-beam frame structure according to the second embodiment, as shown in Figures 5(A) and 5(B). [Modes for carrying out the invention]

[0024] (First Embodiment) First, I will describe the first embodiment.

[0025] (Column-beam frame structure) Figure 1 shows a lower precast column 20L, an upper precast column 20U, and a precast joint member 30 to which the column-beam frame structure according to this embodiment is applied. The lower precast column 20L and the upper precast column 20U are joined via the precast joint member 30. These lower precast column 20L, upper precast column 20U, and precast joint member 30 constitute a part of the column-beam frame 10.

[0026] Note that the lower precast column 20L is an example of a concrete column.

[0027] (Lower precast column, upper precast column) The lower surface of a precast joint member 30 is detachably joined to the upper surface of the lower precast column 20L. The lower surface of the upper precast column 20U is also detachably joined to the upper surface of the precast joint member 30. The upper precast column 20U is erected on the upper surface of the lower precast column 20L via the precast joint member 30, and together with the lower precast column 20L, constitutes a column.

[0028] In this embodiment, the lower precast column 20L and the upper precast column 20U have the same configuration. Therefore, the configuration of the lower precast column 20L will be described below, and the description of the configuration of the upper precast column 20U will be omitted as appropriate.

[0029] The lower precast column 20L is made of precast concrete and is formed in a rectangular column shape. The lower precast column 20L is made of reinforced concrete. Multiple assembly reinforcements 22 and shear reinforcements 24 are embedded around the outer perimeter of this lower precast column 20L.

[0030] Multiple (four in this embodiment) reinforcing bars 22 are arranged at each corner of the lower precast column 20L, along the material axis direction of the lower precast column 20L. Multiple shear reinforcement bars 24 are arranged around these reinforcing bars 22.

[0031] Multiple shear reinforcement bars 24 are bent in a rectangular ring shape in a plan view and surround multiple assembly bars 22. Furthermore, the multiple shear reinforcement bars 24 are supported by multiple assembly bars 22 at intervals along the axial direction of the lower precast column 20L.

[0032] Multiple sheath pipes 26 are embedded in the lower precast column 20L. The multiple (four in this embodiment) sheath pipes 26 are formed in a cylindrical shape and are arranged inside the multiple shear reinforcement bars 24. The multiple sheath pipes 26 are also arranged along the material axis direction of the lower precast column 20L and extend along the entire length of the lower precast column 20L. These sheath pipes 26 form multiple through holes 26H that penetrate the lower precast column 20L in the material axis direction.

[0033] Furthermore, the first PC steel members 60, which will be described later, are slidably inserted into each through-hole 26H.

[0034] (Precast joint members) The precast joint member 30 is made of precast concrete. This precast joint member 30 has a concrete joint section 40 and a plurality of steel beam brackets 50.

[0035] The concrete joint section 40 is formed in a rectangular parallelepiped shape and is positioned between it and the lower surface of the upper precast column 20U. Furthermore, the outer shape of the concrete joint section 40 matches the outer shapes of the lower precast column 20L and the upper precast column 20U in a plan view.

[0036] The concrete joint section 40 is made of steel-reinforced concrete. Multiple assembly reinforcements 42 and shear reinforcements 44 are embedded in the outer periphery of this concrete joint section 40.

[0037] Multiple (four in this embodiment) reinforcing bars 42 are arranged vertically at each corner of the concrete joint 40. Multiple shear reinforcement bars 44 are arranged around these reinforcing bars 42.

[0038] Multiple shear reinforcement bars 44 are bent into a rectangular ring shape in a plan view and surround multiple assembly bars 42. Furthermore, the multiple shear reinforcement bars 44 are supported by the multiple assembly bars 42 with spacing between them in the vertical direction.

[0039] Multiple sheath pipes 46 are embedded in the concrete joint 40. The multiple (four in this embodiment) sheath pipes 46 are formed in a cylindrical shape and are arranged inside the multiple shear reinforcement bars 44.

[0040] Multiple sheath pipes 46 are arranged vertically and extend along the entire length of the concrete joint 40. These sheath pipes 46 form multiple through holes 46H that penetrate the concrete joint 40 vertically. In a plan view, these through holes 46H are located in the same positions as the through holes 26H formed in the lower precast column 20L and the upper precast column 20U.

[0041] The concrete joint section 40 is placed on the upper surface of the lower precast column 20L via a plurality of packings 32. The plurality of packings 32 function as sealing materials to suppress the inflow of joint material M into the through holes 26H and 46H formed in the lower precast column 20L and the concrete joint section 40, and also function as spacers to secure a joint space between the upper surface of the lower precast column 20L and the lower surface of the concrete joint section 40.

[0042] Each packing 32 is formed in a cylindrical shape and is positioned to surround the through-hole 26H on the upper surface of the lower precast column 20L and the through-hole 46H on the lower surface of the concrete joint 40. In this state, a joint material (filler) M such as mortar or grout is filled into the joint space between the upper surface of the lower precast column 20L and the lower surface of the concrete joint 40.

[0043] Similarly, the lower surface of the upper precast column 20U is placed on the upper surface of the concrete joint 40, more specifically on the upper surface of the anchoring plate 62, which will be described later, via a plurality of packings 32. Each packing 32 is positioned to surround the through-hole 46H in the upper surface of the concrete joint 40 and the through-hole 26H in the lower surface of the upper precast column 20U. In this state, joint material (filler) M is filled into the joint space between the upper surface of the concrete joint 40 and the lower surface of the upper precast column 20U.

[0044] Here, the first PC steel members 60 are slidably inserted into the multiple through holes 26H and 46H formed in the lower precast column 20L and the concrete joint section 40, respectively.

[0045] The first PC steel member 60 is formed, for example, from an unbonded PC steel bar (unbonded PC steel member). The lower end of this first PC steel member 60 is fixed to a structural member such as a foundation (not shown), for example. On the other hand, the upper end of the first PC steel member 60 is anchored to the upper surface of the concrete joint 40.

[0046] Specifically, recesses 48 are formed around the periphery of the through-holes 46H on the upper surface of the concrete joint portion 40. As shown in Figure 2, the multiple (four in this embodiment) recesses 48 are formed in a rectangular shape in plan view. A fixing plate 62 is housed in each recess 48.

[0047] The recessed portion 48 may be provided on the upper surface of the concrete joint portion 40 as needed, and can be omitted as appropriate.

[0048] The anchoring plate 62 is formed in a rectangular shape in plan view, for example, from a steel plate. A through hole is formed in the center of the anchoring plate 62. The first PC steel member 60 passes through this through hole.

[0049] A fixing device 64, such as a nut attached to the first PC steel member 60, is secured to the upper surface of the fixing plate 62. As a result, the first PC steel member 60 is fixed to the upper surface of the concrete joint 40 in a tensioned state.

[0050] The tension force introduced into the first PC steel bar 60 is adjusted by the amount the anchoring device 64 is tightened (threaded in) relative to the first PC steel bar 60.

[0051] The upper end of the first PC steel member 60 is slidably inserted into the through hole 26H of the upper precast column 20U. The lower end of the second PC steel member 70 is connected to the upper end of the first PC steel member 60 via a coupler (connector) 72.

[0052] The second PC steel member 70 is slidably inserted into the through hole 26H of the upper precast column 20U. The upper end of this second PC steel member 70 is fixed to the upper surface of a precast joint member (not shown) that is detachably joined to the upper surface of the upper precast column 20U, for example.

[0053] Note that the first PC steel bar 60 and the second PC steel bar 70 are examples of PC steel bars.

[0054] (Steel beam bracket) As shown in Figure 2, the multiple steel beam brackets 50 are joined in a cross shape in plan view, and their intersection (center) is embedded in the concrete joint 40. The ends of each steel beam bracket 50 protrude from each side of the concrete joint 40.

[0055] As shown in Figure 1, the steel beam bracket 50 is formed, for example, from an H-shaped steel. The steel beam bracket 50 also has a pair of flange portions 52 that face each other in the vertical direction and a web portion 54 that connects the pair of flange portions 52. A steel beam member 80 is joined to the end of this steel beam bracket 50.

[0056] Furthermore, the precast joint member 30 may be provided with at least one steel beam bracket 50 whose end protrudes from the side surface of the concrete joint portion 40.

[0057] (Steel beam members) The steel beam member 80, together with the steel beam bracket 50, constitutes a beam. For example, the steel beam member 80 is formed from an H-shaped steel beam having the same shape and cross-sectional area as the steel beam bracket 50. This steel beam member 80 has a pair of flange portions 82 that face each other in the vertical direction, and a web portion 84 that connects the pair of flange portions 82.

[0058] The steel beam bracket 50 and the steel beam member 80 are arranged so that their respective flange portions 52, 82 and web portions 54, 84 are continuous. The flange portions 52, 82 of the steel beam bracket 50 and the steel beam member 80 are joined to each other via upper and lower splice plates 90 using high-strength bolts 92 and nuts 94. The web portions 54, 84 of the steel beam bracket 50 and the steel beam member 80 are joined to each other via splice plate 100 using high-strength bolts 102 and nuts.

[0059] Furthermore, the connection structure between the steel beam member 80 and the steel beam bracket 50 is not limited to bolted connections; for example, it may also be a welded connection.

[0060] (Construction method of column-beam frame structure) Next, an example of a construction method for the column-beam frame structure according to the first embodiment will be described.

[0061] (Construction process for erecting the lower precast columns) First, as shown in Figure 3, the lower precast column 20L is erected during the lower precast column erection process. First PC steel members 60 are slidably inserted into each through-hole 26H of the lower precast column 20L. Furthermore, the upper ends of each first PC steel member 60 extend upward from the upper surface of the lower precast column 20L.

[0062] (Precast joint component installation process) Next, as shown in Figure 4, in the precast joint member construction process, the precast joint member 30 is lifted by a lifting machine (not shown), and the concrete joint portion 40 of the precast joint member 30 is placed on the upper surface of the lower precast column 20L via a plurality of packings 32.

[0063] At this time, multiple first PC steel members 60 extending from the upper surface of the lower precast column 20L are slidably inserted into multiple through holes 46H formed in the concrete joint 40. The upper end of each first PC steel member 60 is then extended upward from the upper surface of the concrete joint 40.

[0064] Next, the outer perimeter of the joint between the upper surface of the lower precast column 20L and the lower surface of the concrete joint section 40 is sealed with a tube formwork or the like (not shown), and joint material M such as grout is filled into the joint through filling holes (not shown).

[0065] Next, the upper ends of the multiple first PC steel members 60 are fixed to the upper surface of the concrete joint 40. Specifically, fixing plates 62 are attached to the upper ends of the first PC steel members 60, and the fixing plates 62 are placed in the recesses 48 formed on the upper surface of the concrete joint 40.

[0066] Furthermore, a fixing device 64 is attached to the upper end of the first PC steel member 60, and the fixing device 64 is locked to the upper surface of the fixing plate 62, thereby tensioning the first PC steel member 60. As a result, the upper end of the first PC steel member 60 is fixed to the upper surface of the concrete joint 40, and the lower surface of the concrete joint 40 is pressure-bonded to the upper surface of the lower precast column 20L via the joint material M.

[0067] (Upper precast column construction process) Next, in the upper precast column construction process, the upper precast column 20U is lifted using a lifting machine (not shown) and held above the lower precast column 20L.

[0068] In this state, the lower ends of the second PC steel members 70, which are slidably inserted into the through holes 26H of the upper precast column 20U, are connected to the upper ends of the multiple first PC steel members 60 extending from the upper surface of the concrete joint 40 via a coupler 72.

[0069] Next, the lower surface of the upper precast column 20U is placed on the upper surface of the concrete joint portion 40 of the precast joint member 30 via a plurality of packings 32.

[0070] Next, the outer perimeter of the joint between the upper surface of the concrete joint 40 and the lower surface of the upper precast column 20U is sealed with a tube formwork or the like (not shown), and joint material M such as grout is filled into the joint through filling holes (not shown).

[0071] (Beam member construction process) Next, as shown in Figure 1, in the beam member construction process, the steel beam member 80 is lifted by a lifting machine (not shown) and joined to the steel beam bracket 50 of the precast joint member 30.

[0072] The above construction procedure is repeated to construct a multi-layered column-beam frame 10. When repeating the above construction procedure, the upper precast column 20U and the second PC steel member 70 are appropriately replaced with the lower precast column 20L and the first PC steel member 60.

[0073] Furthermore, the above construction procedure can be modified as appropriate. For example, in the above construction procedure, the upper precast column 20U was joined to the precast joint member 30, and then the steel beam member 80 was joined to the steel beam bracket 50 of the precast joint member 30. However, for example, the steel beam member 80 could be joined to the steel beam bracket 50 of the precast joint member 30, and then the upper precast column 20U could be joined to the precast joint member 30.

[0074] (Mechanism of Action and Effects) Next, the operation and effects of the first embodiment will be described.

[0075] As shown in Figure 1, the column-beam frame structure according to this embodiment comprises a lower precast column 20L, a precast joint member 30, and an upper precast column 20U.

[0076] The precast joint member 30 has a concrete joint section 40 and a plurality of steel beam brackets 50. The concrete joint section 40 is positioned between the lower precast column 20L and the upper precast column 20U. These concrete joint section 40, the lower precast column 20L, and the upper precast column 20U are detachably joined by a plurality of first PC steel members 60 and second PC steel members 70.

[0077] Multiple steel beam brackets 50 are embedded in the concrete joint 40, with their ends protruding from the sides of the concrete joint 40. Steel beam members 80 are joined to the ends of these steel beam brackets 50.

[0078] As mentioned above, the concrete joint portion 40 of the precast joint member 30, the lower precast column 20L, and the upper precast column 20U are detachably joined by a plurality of first PC steel members 60 and second PC steel members 70.

[0079] Therefore, when dismantling the column-beam frame 10, the precast joint member 30 can be removed from the lower precast column 20L, and the upper precast column 20U can be removed from the precast joint member 30. This allows the lower precast column 20L, the precast joint member 30, and the upper precast column 20U to be reused.

[0080] Thus, in this embodiment, the lower precast column 20L, the precast joint member 30, and the upper precast column 20U can be reused as structural members.

[0081] Furthermore, the first PC steel member 60 extends from the upper surface of the lower precast column 20L and slides vertically through the concrete joint portion 40 of the precast joint member 30. The anchoring device 64 anchors the tensioned first PC steel member 60 to the upper surface of the concrete joint portion 40 and presses the lower surface of the concrete joint portion 40 and the upper surface of the lower precast column 20L together via the joint material M.

[0082] By using the first PC steel member 60 and the anchoring device 64 in this manner, the lower precast column 20L and the precast joint member 30 can be easily and detachably joined together.

[0083] Similarly, in this embodiment, the precast joint member 30 and the upper precast column 20U can be easily and detachably joined using the first PC steel member 60 and the second PC steel member 70.

[0084] Furthermore, the first PC steel member 60 is not anchored to the upper surface of the lower precast column 20L. In other words, the first PC steel member 60 is not anchored to the upper surface of the lower precast column 20L, but is anchored to the upper surface of the concrete joint portion 40 of the precast joint member 30.

[0085] As a result, in this embodiment, the constructability is improved compared to the case where the first PC steel material 60 is fixed to the upper surface of the lower precast column 20L and the upper surface of the concrete joint portion 40, respectively.

[0086] (Second embodiment) Next, a second embodiment will be described. In the second embodiment, components and the like that have the same configuration as in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0087] As shown in Figures 5(A) and 5(B), in the column-beam frame structure according to the second embodiment, a bracket non-yielding means is provided at the end of the steel beam member 80 to yield the steel beam member 80 before the steel beam bracket 50 yields.

[0088] Specifically, a pair of notches 110 are formed in the upper and lower flange portions 82 at the ends of the steel beam member 80, respectively, to serve as bracket non-yielding means. The pair of notches 110 are formed in a concave shape at both ends of the upper and lower flange portions 82 of the steel beam member 80.

[0089] Furthermore, the pair of notches 110 are positioned opposite each other in the beam width direction of the steel beam member 80. This pair of notches 110 partially reduces the cross-sectional area of ​​the end of the steel beam member 80 compared to the cross-sectional area of ​​the steel beam bracket 50. As a result, during an earthquake, the steel beam member 80 yields at the portion where the notches 110 are formed (the portion with reduced cross-section) before the steel beam bracket 50 yields.

[0090] (Mechanism of Action and Effects) Next, the operation and effects of the second embodiment will be described.

[0091] According to this embodiment, the end of the steel beam member 80 is joined to the end of the steel beam bracket 50. A pair of notches 110 are formed in the upper and lower flange portions 82 at the end of the steel beam member 80. This pair of notches 110 partially reduces the cross-sectional area of ​​the end of the steel beam member 80 to be smaller than the cross-sectional area of ​​the steel beam bracket 50.

[0092] As a result, during an earthquake, the steel beam member 80 yields at the portion where the notch 110 is formed (the portion with reduced cross-section) before the steel beam bracket 50 yields. Therefore, damage to the steel beam bracket 50 during an earthquake is suppressed. Consequently, the precast joint member 30 can be reused more easily.

[0093] Furthermore, if the steel beam bracket 50 yields during an earthquake, cracks and fissures are more likely to occur on the side surface of the concrete joint 40. In contrast, in this embodiment, since the steel beam bracket 50 does not yield during an earthquake, cracks and fissures on the side surface of the concrete joint 40 are suppressed. Therefore, the precast joint member 30 becomes even easier to reuse.

[0094] (Modified version of the second embodiment) Next, a modified example of the second embodiment will be described.

[0095] In the second embodiment described above, the bracket non-yielding means is a notch 110. However, the bracket non-yielding means is not limited to a notch 110, and may be an opening, for example.

[0096] Specifically, as shown in the modified examples in Figures 6(A) and 6(B), an opening 112 is formed in the web portion 84 at the end of the steel beam member 80. The opening 112 is formed in the shape of a slit extending in the direction of the axial direction of the steel beam member 80. This opening 112 partially reduces the cross-sectional area of ​​the end of the steel beam member 80 to be smaller than the cross-sectional area of ​​the steel beam bracket 50.

[0097] As a result, during an earthquake, the steel beam member 80 can be yielded at the portion where the opening 112 is formed (the portion with reduced cross-section) before the steel beam bracket 50 yields. Therefore, the same effects as in the second embodiment can be obtained.

[0098] Next, in the modified examples shown in Figures 7(A) and 7(B), a vertical stepped portion 120 is provided at the end of the steel beam member 80 as a bracket non-yielding means. The vertical stepped portion 120 is formed at the lower part of the steel beam member 80, and this vertical stepped portion 120 makes the beam depth T2 of the steel beam member 80 lower than the beam depth T1 of the steel beam bracket 50. In other words, the steel beam member 80 is a drop haunch (vertical haunch).

[0099] As a result, during an earthquake, the steel beam member 80 can be yielded in the portion where the beam depth has been reduced by the vertical step portion 120, before the steel beam bracket 50 yields. Therefore, the same effects as in the second embodiment can be obtained.

[0100] The structure of the drop haunch provided on the steel beam member 80 can be modified as appropriate. For example, in the modified examples shown in Figures 8(A) and 8(B), the steel beam member 80 is made into a drop haunch by providing a haunch steel frame 130 at the end of the steel beam member 80.

[0101] Specifically, the haunch steel frame 130 is formed, for example, from a T-shaped steel (cut T-steel) and has a web portion 132 and a flange portion 134. The upper end of the web portion 132 is joined by welding (fillet welding, etc.) to the lower surface of the lower flange portion 82 of the steel beam member 80, while abutting against it. The flange portion 134 is provided at the lower end of this web portion 132.

[0102] The flange portion 134 is joined to the lower flange portion 52 of the steel beam bracket 50 via upper and lower splice plates 90 using high-strength bolts 92 and nuts 94. In addition, the steel beam member 80 and the haunch steel frame 130 are reinforced with stiffeners 136.

[0103] In this way, the haunch steel frame 130 provided at the lower part of the end of the steel beam member 80 forms a vertical stepped portion 121 at the end of the steel beam member 80, which serves as a bracket non-yielding means. This vertical stepped portion 121 makes the beam depth T2 of the steel beam member 80 lower than the beam depth T1 of the steel beam bracket 50.

[0104] As a result, during an earthquake, the steel beam member 80 can be yielded in the portion where the beam depth has been reduced by the vertical step portion 121, before the steel beam bracket 50 yields. Therefore, the same effects as in the second embodiment can be obtained.

[0105] Next, in the modified examples shown in Figures 9(A) and 9(B), a horizontal step portion 122 is provided between the steel beam bracket 50 and the steel beam member 80 as a bracket non-yielding means. The horizontal step portion 122 is formed by making the beam width W2 of the steel beam member 80, i.e., the width W2 of the upper and lower flange portions 82, narrower than the beam width W1 of the steel beam bracket 50, i.e., the width W1 of the upper and lower flange portions 52 of the steel beam bracket 50.

[0106] As a result, in the event of an earthquake, before the steel beam bracket 50 yields, the steel beam member 80 can be made to yield in the portion where the beam width W2 of the steel beam member 80 is narrowed by the horizontal step portion 122. Therefore, the same effects as in the second embodiment can be obtained.

[0107] Next, in the modified examples shown in Figures 10(A) and 10(B), a sliding resistance adjustment means, which serves as a bracket non-yielding means, is provided at the joint between the steel beam bracket 50 and the steel beam member 80.

[0108] One example of a means for adjusting the sliding resistance is a high-strength bolt 92, 102 and nut 94 provided at the joint between the steel beam bracket 50 and the steel beam member 80. These high-strength bolts 92, 102 and nuts 94 adjust the sliding resistance of the joint so that, during an earthquake, the joint between the steel beam bracket 50 and the steel beam member 80 slides before the steel beam bracket 50 yields.

[0109] The sliding resistance of the joint between the steel beam bracket 50 and the steel beam member 80 is adjusted by the axial force introduced into the high-strength bolts 92 and 102, as well as the diameter and number of the high-strength bolts 92 and 102. As a result, during an earthquake, the joint between the steel beam bracket 50 and the steel beam member 80 slides before the steel beam bracket 50 yields, thereby suppressing damage to the steel beam bracket 50. Therefore, the same effects as in the second embodiment can be obtained.

[0110] Furthermore, in this embodiment, the number of high-strength bolts 92 and 102 is adjusted so that the joint between the steel beam member 80 and the splice plates 90 and 100 slides before the joint between the steel beam bracket 50 and the splice plates 90 and 100.

[0111] Specifically, the number of high-strength bolts 92 connecting the flange portion 52 of the steel beam bracket 50 to the splice plate 90 is greater than the number of high-strength bolts 92 connecting the flange portion 82 of the steel beam member 80 to the splice plate 90.

[0112] As a result, during an earthquake, the joint between the flange portion 82 of the steel beam member 80 and the splice plate 90 slips before the joint between the flange portion 52 of the steel beam bracket 50 and the splice plate 90, further suppressing damage to the steel beam bracket 50.

[0113] Furthermore, the means for adjusting the sliding resistance is not limited to high-strength bolts 92, 102 and nuts, but may also be, for example, a sliding material (sliding plate) provided at the joint between the steel beam bracket 50 and the steel beam member 80.

[0114] Next, although not shown in the diagram, the steel types of the steel beam brackets 50 and steel beam members 80 may be changed so that, for example, the steel beam members 80 yield before the steel beam brackets 50 during an earthquake. For example, the steel beam brackets 50 may be made of high-strength steel and the steel beam members 80 may be made of ordinary-strength steel.

[0115] As a result, during an earthquake, the steel beam member 80 yields before the steel beam bracket 50 yields, thus suppressing damage to the steel beam bracket 50. Therefore, the same effects as in the second embodiment can be obtained.

[0116] By providing a bracket non-yielding means on at least one of the steel beam bracket 50 and the steel beam member 80 in this manner, damage to the steel beam bracket 50 during an earthquake is suppressed, making it easier to reuse the precast joint member 30. The various bracket non-yielding means described above may be combined as appropriate.

[0117] (Modifications of the first and second embodiments) Next, modifications of the first and second embodiments described above will be explained. In the following, various modifications will be explained using the first embodiment as an example, but these modifications can also be appropriately applied to the second embodiment.

[0118] In the first embodiment described above, the first PC steel member 60 is not fixed to the upper surface of the lower precast column 20L, but is fixed to the upper surface of the concrete joint portion 40 of the precast joint member 30. However, the first PC steel member 60 is not limited to the upper surface of the concrete joint portion 40, but may also be fixed to the upper surface of the lower precast column 20L, for example. Alternatively, the first PC steel member 60 may be fixed to the upper surface of the lower precast column 20L and the upper surface of the concrete joint portion 40, respectively.

[0119] Furthermore, in the first embodiment described above, the division of the nodes in the lower precast column 20L and the upper precast column 20U can be changed as appropriate, and the lower precast column 20L and the upper precast column 20U may, for example, have one node per layer, one node per two layers, or one node per three layers.

[0120] Furthermore, in the first embodiment described above, the lower precast column 20L, which serves as the concrete column, is made of precast concrete. However, the concrete column (lower concrete column) is not limited to being made of precast concrete; it may also be made of cast-in-place concrete.

[0121] Furthermore, in the first embodiment described above, the upper precast column 20U is detachably joined to the precast joint member 30. However, for example, on the top floor of a structure (building), the upper precast column 20U is omitted.

[0122] 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]

[0123] 10 Column beam frame 20L Lower precast column (concrete column) 30 Precast joint members 40 Concrete joint section 50 Steel beam bracket 60 Daiichi PC steel material (PC steel material) 70 Second PC steel material (PC steel material) 80 Steel beam members 92 High-strength bolts (bracket non-yielding means) 94. Nut (bracket non-yielding means) 102 High-strength bolt (bracket non-yielding means) 112 Opening (bracket non-yielding means) 120 Vertical stepped section (bracket non-yielding means) 121 Vertical stepped section (bracket non-yielding means) 122 Horizontal step section (bracket non-yielding means) M Joint material

Claims

1. Concrete pillars and A precast joint member having a concrete joint portion that is detachably joined to the concrete column, and a steel beam bracket that is embedded in the concrete joint portion and whose end protrudes from the side surface of the concrete joint portion, A column-beam frame structure equipped with these features.

2. A steel beam member whose end is joined to the end of the steel beam bracket, A bracket non-yielding means is provided on at least one of the steel beam bracket and the steel beam member, which yields the steel beam member or slides the joint between the steel beam bracket and the steel beam member before the steel beam bracket yields, The column-beam frame structure according to claim 1, comprising:

3. A PC steel member extends from the upper surface of the concrete column and penetrates the concrete joint portion in a way that allows it to slide vertically, A fixing device for fixing the tensioned PC steel material to the upper surface of the concrete joint and for press-fitting the lower surface of the concrete joint and the upper surface of the concrete column via a joint material, A column-beam frame structure according to claim 1 or claim 2, comprising the above.

4. The aforementioned PC steel material is not anchored to the upper surface of the concrete column. The column-beam frame structure according to claim 3.

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