Exposed column base construction

Abstract

To provide an exposed type column base foundation structure with main reinforcements of a foundation beam mechanically anchored to a column type foundation body, excellent in compressive resistance against compressive force applied from a column base to the oblique direction and having good workability.SOLUTION: In an exposed type column base foundation structure 100, a base plate 41 is fixed on a column type foundation body 10 with anchor bolts 50, a steel column 30 is fixed to the base plate 41, and first fixing plates 26 at end parts of main reinforcements 25 of a foundation beam 20 fixed to a side face 13 of the column type foundation body 10 are fixed to the column type foundation body 10. The anchor bolts 50 have second fixing plates 51 at lower ends thereof, and include multiple first anchor bolts 50A arranged on the foundation beam 20 side and multiple second anchor bolts 50B arranged on a side opposite to the foundation beam 20. A fixing part reinforcement member 60 is provided which connects the multiple first anchor bolts 50A with each other on the respective second fixing plates 51.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an exposed column base foundation structure.

Background Art

[0002] As a foundation structure of a steel column base, there are an exposed column base foundation structure in which a base plate fixed by anchor bolts embedded in a reinforced concrete foundation (column-shaped foundation body) is exposed at the top end of the column-shaped foundation body, a root-wrapped column base foundation structure in which the base plate is embedded in a foundation (root-wrapped concrete foundation), and an embedded column base foundation structure in which the base plate is embedded in a reinforced concrete foundation. Among them, the exposed column base foundation structure is generally designed as a semi-fixed column base, and the rigidity can be changed from a pinned column base to a fixed column base during design, and it has the advantage of being easier to construct than other column base foundation structures.

[0003] On the side surface of the column-shaped foundation body forming the above-mentioned exposed column base foundation structure, foundation beams extending to one side or multiple sides are often fixed, and the main reinforcement bars (upper-end main reinforcement bars and lower-end main reinforcement bars) forming the foundation beams are fixed to the column-shaped foundation body. When trying to ensure the fixing of this main reinforcement bar with a predetermined fixing length, cases may occur where the steel bars become intricate inside the column-shaped foundation body and it becomes difficult to accommodate the steel bars, or cases where the concrete forming the column-shaped foundation body does not spread throughout due to the intricacy of the steel bars. Therefore, problems can occur on both the construction side and the quality side. In some cases, so-called mechanical fixing, in which the fixing of the main reinforcement bar is performed by a fixing plate provided at its end, is applied.

[0004] In column-type foundations, when horizontal forces act on the columns during an earthquake, a compressive force can act from the base of the column, attempting to push the bottom surface of the column-type foundation diagonally downwards. Therefore, when anchoring the main reinforcement of the foundation beam in a column-type foundation using mechanical anchoring, measures are taken to reinforce the shear of the column-type foundation, such as making its bottom protrude several centimeters to more than ten centimeters relative to the foundation beam, or by arranging so-called "hairpin" reinforcement in a U-shape when viewed from the front. However, measures to make the bottom surface of the column-type foundation protrude lower than the foundation beam require lowering only the bottom surface of the column-type foundation by several centimeters during the groundwork, which increases the construction burden on site and raises construction costs, including the management of auxiliary materials, among other issues.

[0005] Furthermore, even if the main reinforcement of the foundation beam is mechanically anchored, the situation remains that the reinforcement bars are intertwined inside the column-shaped foundation, making it difficult to insert the reinforcement bars from below. Therefore, instead of inserting the reinforcement bars from below, measures such as inserting J-shaped reinforcement bars (J-shaped in front view) from above the column-shaped foundation and temporarily fixing them to multiple anchor bolts that have already been installed or to the stirrups around each anchor bolt are sometimes taken. However, this measure still involves inserting more reinforcement bars into an already intertwined network of bars, and it still contains challenges such as difficulty in insertion and a high construction load.

[0006] Based on the above, in an exposed column base foundation structure in which the main reinforcement of the foundation beam is mechanically anchored to the column-shaped foundation, there is a need for an exposed column base foundation structure that is excellent in compressive resistance against compressive forces acting diagonally from the column base and also has good constructability.

[0007] Here, Patent Document 1 proposes a column-type foundation for an exposed column base, in which multiple vertical reinforcements are arranged in an annular pattern along the vertical height direction within a column-type concrete body with a square cross-section, multiple hoop reinforcements are formed in an annular pattern surrounding the outer perimeter of the vertical reinforcements and are arranged in multiple stages in the vertical height direction of the vertical reinforcements, and multiple anchor bolts are arranged in an annular pattern positioned inward from the vertical reinforcements, and an exposed column base is installed and fixed. In this exposed column-type foundation for an exposed column base, multiple reinforcing plates are provided between the anchor bolts and the outer surface of the column-type concrete body, inscribed within multiple hoop reinforcements from the uppermost hoop reinforcement to the lower hoop reinforcements and corresponding to each anchor bolt. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-94460 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] In the exposed column base column foundation described in Patent Document 1, multiple reinforcing plates corresponding to each anchor bolt are provided between the anchor bolt and the outer surface of the column concrete body, with multiple hoop reinforcements inscribed within the hoop reinforcements from the uppermost to the lower hoop reinforcements. Therefore, similar to the reinforcement arrangement of J-shaped reinforcements described above, the construction load remains high because another member is inserted into the area where the reinforcement bars in the column foundation are intertwined.

[0010] This invention has been made in view of the above problems, and aims to provide an exposed column base foundation structure in which the main reinforcement of the foundation beam is mechanically anchored to the column-shaped foundation, which has excellent compressive resistance against compressive forces acting diagonally from the column base and also has good constructability. [Means for solving the problem]

[0011] To achieve the above objective, one embodiment of the exposed column base foundation structure according to the present invention is: An exposed column base foundation structure is characterized in which a base plate is placed directly or indirectly on a reinforced concrete column-shaped foundation, a steel column is fixed to the upper surface of the base plate, anchor bolts fixed to the base plate are embedded in the column-shaped foundation, a reinforced concrete foundation beam is fixed to the side of the column-shaped foundation, and a first anchoring plate at the end of the main reinforcement of the foundation beam is anchored to the column-shaped foundation, The aforementioned anchor bolt is provided with a second anchoring plate at its lower end, and the anchor bolt includes a plurality of first anchor bolts arranged on the foundation beam side and a plurality of second anchor bolts arranged on the opposite side of the foundation beam. The anchoring portion is characterized by having a reinforcing member that connects a plurality of the first anchor bolts to each other on the respective second anchoring plates.

[0012] According to this embodiment, in an exposed column base foundation structure in which a reinforced concrete foundation beam is fixed to the side of a column-shaped foundation, and the first anchoring plates at the ends of the main reinforcement bars (upper and lower main reinforcement bars) of the foundation beam are anchored to the column-shaped foundation, the bearing area is increased by connecting the anchoring reinforcement members to each other on the second anchoring plates of the multiple first anchor bolts, which are fixed to a base plate and have a second anchoring plate at their lower end and are arranged on the foundation beam side. This forms a compression strut that resists the compressive force acting diagonally from the column base, and enables smooth transmission of bearing pressure to the first anchor bolts. Furthermore, since the anchoring reinforcement members only need to be placed on the second anchoring plates at the lower ends of the multiple first anchor bolts, they can be easily inserted from below or the side after the anchor bolts, the surrounding stirrups, and the upper and lower main reinforcement bars extending from the foundation beam have been arranged, and placed on the second anchoring plates at the lower ends of the multiple first anchor bolts, which is an area where the reinforcement bars are not intertwined.

[0013] In this case, when the columnar foundation is rectangular in shape, the foundation beam can be fixed to one side of the columnar foundation or to two or more sides. In the configuration where one foundation beam is fixed to one side of the columnar foundation, the first anchor bolt located on the side of the foundation beam and the second anchor bolt located on the opposite side of the foundation beam are uniquely determined. For example, one configuration is one in which there are two first anchor bolts and two second anchor bolts.

[0014] On the other hand, in a configuration where a columnar foundation is equipped with, for example, four anchor bolts, and two foundation beams are fixed to two mutually orthogonal sides, two first anchor bolts and two second anchor bolts for one foundation beam become, for the other foundation beam, one of the first anchor bolts becomes a second anchor bolt, and similarly, one of the second anchor bolts becomes a first anchor bolt. Therefore, in the latter configuration, since the two bolts that become first anchor bolts for each foundation beam are connected by anchoring reinforcement members, two anchoring reinforcement members are connected to the one common first anchor bolt.

[0015] In this embodiment, "a base plate is placed directly or indirectly on a columnar foundation" means that in addition to the form in which the base plate is directly placed on the top surface of the columnar foundation, the base plate is placed on the top surface via a grout layer (and therefore, the base plate is placed indirectly).

[0016] Furthermore, in another embodiment of the exposed column base foundation structure according to the present invention, The aforementioned anchoring reinforcement member comprises a plate and a reinforcing rib perpendicular to the plate, which is fixed to a part of the end face of the plate. The end face of the plate is provided with a plurality of accommodating grooves into which a plurality of the first anchor bolts are fitted.

[0017] According to this embodiment, the anchoring reinforcement member has a plate with a receiving groove into which the first anchor bolt fits, and a reinforcing rib fixed to a part of the end face of the plate and perpendicular to the plate. This allows the bearing area to be increased with a simple anchoring reinforcement member, and the plate contributing to the bearing area is effectively reinforced by the reinforcing rib, providing strength to effectively transmit the bearing pressure to the first anchor bolt. For example, if there are two first anchor bolts, it is desirable that the reinforcing rib be provided in the area of ​​the end face of the plate sandwiched between the two receiving grooves.

[0018] Here, the plate is, for example, a flat steel plate with a rectangular shape in plan view, and multiple (for example, two) receiving grooves are provided on one of its long sides, and reinforcing ribs, for example, made of flat steel, are fixed between them by welding or the like. Furthermore, there may be various configurations for this rectangular plate in plan view, such as a configuration in which reinforcing ribs are provided extending upward or downward from the plate to the end face having the receiving grooves, a configuration in which reinforcing ribs are provided extending vertically from the plate, or a configuration in which reinforcing ribs are also provided on the other end face that is paired with the end face having the receiving grooves.

[0019] Furthermore, in another embodiment of the exposed column base foundation structure according to the present invention, The plurality of second anchor bolts are housed in the receiving grooves of a separate anchoring reinforcement member and are connected to one another.

[0020] According to this aspect, in addition to the fixing part reinforcing member that transmits the bearing pressure to the plurality of first anchor bolts, a separate fixing part reinforcing member that transmits the bearing pressure to the plurality of second anchor bolts is provided. As a result, when the steel column is displaced in the direction of moving away from the foundation beam (the direction of opening), the bearing pressure that resists the compressive force generated in the column-type foundation body can be transmitted to the first anchor bolts, and when the steel column is displaced in the direction of approaching the foundation beam (the direction of closing), the bearing pressure that resists the compressive force generated in the column-type foundation body can be transmitted to the second anchor bolts. According to the inventors of the present invention, since the bearing capacity against the former compressive force is generally smaller than that against the latter among the bearing capacities against both compressive forces, in the present invention, a fixing part reinforcing member that connects the plurality of first anchor bolts to each other is an essential component.

[0021] Also, in another aspect of the exposed column base foundation structure according to the present invention, The fixing part reinforcing material has a plate and a reinforcing rib that is fixed to a part of the end face of the plate and is orthogonal to the plate. The end face of the plate is provided with a plurality of accommodation grooves into which all of the plurality of first anchor bolts and the second anchor bolts fit.

[0022] According to this aspect, since the fixing part reinforcing member has a plate provided with accommodation grooves into which the first anchor bolts and the second anchor bolts fit, and a reinforcing rib that is fixed to a part of the end face of the plate and is orthogonal to the plate, the bearing area can be increased with a fixing part reinforcing member having a simple structure, the plate contributing to the bearing area is effectively reinforced by the reinforcing rib, and it can have the strength to effectively transmit the bearing pressure to both the first anchor bolts and the second anchor bolts. For example, when there are two first anchor bolts and two second anchor bolts, it is desirable that two accommodation grooves are provided in each of the pair of opposing end faces of the plate, and reinforcing ribs are provided in the regions sandwiched by the two accommodation grooves respectively.

[0023] Also, in another aspect of the exposed column base foundation structure according to the present invention, In the interior of the columnar foundation body, the second fixing plate and the fixing part reinforcing member are disposed at a position lower than the lower end main reinforcement included in the main reinforcement fixed therein.

[0024] According to this aspect, in the interior of the columnar foundation body, by disposing the second fixing plate and the fixing part reinforcing material at a position lower than the lower end main reinforcement that is fixed, a compression strut can be formed from below the columnar foundation body, and it becomes possible to effectively transmit the bearing pressure to the anchor bolt.

Effect of the Invention

[0025] As can be understood from the above description, according to the exposed column base foundation structure of the present invention, in the exposed column base foundation structure in which the main reinforcement of the foundation beam is mechanically fixed to the columnar foundation body, it is excellent in compression resistance against the compressive force acting obliquely from the column base, and an exposed column base foundation structure with good workability can be provided.

Brief Description of the Drawings

[0026] [Figure 1] It is a longitudinal sectional view of an example of the exposed column base foundation structure according to the embodiment. [Figure 2] It is a view taken in the direction of arrow II-II in FIG. 1. [Figure 3] It is a perspective view of an example of the fixing part reinforcing member. [Figure 4] It is a perspective view of another example of the fixing part reinforcing member. [Figure 5] In an example of the exposed column base foundation structure according to the embodiment, it is a view explaining the force generated when the steel column is displaced in the direction of opening with respect to the foundation beam. [Figure 6] It is a longitudinal sectional view of a modified example of the exposed column base foundation structure according to the embodiment. [Figure 7] It is a view taken in the direction of arrow VII-VII in FIG. 6. [Figure 8] In a modified example of the exposed column base foundation structure according to the embodiment, it is a view explaining the force generated when the steel column is displaced in the direction of closing with respect to the foundation beam. [Figure 9]This is a cross-sectional view of another modified example of the exposed column base foundation structure according to the embodiment. [Figure 10] This is a perspective view of yet another example of a reinforcing member for the anchoring section. [Modes for carrying out the invention]

[0027] Hereinafter, an example of an exposed column base foundation structure according to the embodiment will be described with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0028] [Exposed column base foundation structure according to the embodiment] An example of an exposed column base foundation structure according to the embodiment will be described with reference to Figures 1 to 10. Here, Figure 1 is a longitudinal cross-sectional view of an example of an exposed column base foundation structure according to the embodiment, and Figure 2 is a view taken along arrow II-II in Figure 1. Figure 3 is a perspective view of an example of a reinforcing member for the anchorage section, and Figure 5 is a diagram illustrating the force generated when the steel column is displaced in the direction away from the foundation beam in an example of an exposed column base foundation structure according to the embodiment.

[0029] The exposed column base foundation structure 100 is formed by fixing the end face 23 of a reinforced concrete foundation beam 20 to the side face 13 of a reinforced concrete column-shaped foundation body 10, placing a base plate 41 which is welded to the lower end 31 of a steel column 30 via a grout layer 45 on the top surface 11 of the column-shaped foundation body 10, and fixing the base plate 41 to the column-shaped foundation body 10 with a plurality of (four in the illustrated example) anchor bolts 50.

[0030] The steel column 30 is formed from H-shaped steel. However, the steel column may also be formed from other materials such as square steel pipes.

[0031] Of the four anchor bolts 50, the two on the foundation beam 20 side are first anchor bolts 50A, and the two on the opposite side of the foundation beam 20 are second anchor bolts 50B. Each anchor bolt 50 is equipped with a second fixing plate 51 at its lower end, and a nut 52 is tightened on the upper part that protrudes from the base plate 41.

[0032] The column-shaped foundation 10 is a rectangular parallelepiped, with four anchor bolts 50 positioned at the four corners, multiple vertical reinforcement bars 55 placed between each anchor bolt 50, and multiple stirrups 56 surrounding each anchor bolt 50 and vertical reinforcement bars 55, spaced apart in the vertical direction.

[0033] The foundation beam 20 has two levels, upper and lower, each with four upper main reinforcement bars 25A and four lower main reinforcement bars 25B. Multiple stirrups 27 surround each main reinforcement bar 25 and are arranged at intervals along the longitudinal direction of the main reinforcement bar 25.

[0034] Furthermore, each main reinforcement bar 25 is equipped with a first anchoring plate 26 at its end, and the first anchoring plate 26 is positioned near the second anchor bolt 50B and anchored inside the column-shaped foundation 10.

[0035] Inside the column-shaped foundation 10, a reinforcing anchoring member 60 is provided on top of the second anchoring plate 51 of each of the two first anchor bolts 50A, connecting both first anchor bolts 50A to each other.

[0036] More specifically, within the column-shaped foundation 10, the second anchoring plate 51 is located below the lower end main reinforcement 25B of the foundation beam 20, and similarly, the anchoring reinforcement member 60 is positioned below the lower end main reinforcement 25B.

[0037] As clearly shown in Figures 2 and 3, the anchoring reinforcement member 60 has a rectangular steel plate 61 in plan view, and reinforcing ribs 67 that are welded to a portion of each of a pair of end faces 62 and 63 of the plate 61 in a manner perpendicular to the plate 61. In the illustrated example, the reinforcing ribs 67 protrude vertically from the plate 61.

[0038] Of the end faces 62 and 63 of the plate 61, one end face 62 is provided with two accommodating grooves 66 into which two first anchor bolts 50A are fitted.

[0039] As explained below, the plate 61 increases the bearing area, making it possible to effectively transmit the bearing pressure from the plate 61 with a bearing area A (see Figure 2) to the first anchor bolt 50A in response to the compressive force acting on the column-shaped foundation 10. At that time, the plate 61 is effectively reinforced by the reinforcing ribs 67 on a pair of end faces 62 and 63, becoming an anchoring reinforcement member 60 with sufficient strength to effectively transmit the bearing pressure to the first anchor bolt 50A.

[0040] Furthermore, at the end face 62, a reinforcing rib 67 is provided between the two housing grooves 66 that accommodate the first anchor bolts 50A, thereby effectively reinforcing the plate 61 that is pressed in by the two first anchor bolts 50A. In addition, a separate reinforcing rib 67 on the opposing end face 63 increases the rigidity of the entire plate 61.

[0041] As is clear from Figures 1 and 2, the anchoring reinforcement member 60 is generally flat, so after each anchor bolt 50, stirrups 56, and each main reinforcement 25 of the foundation beam 20 are in place, it is inserted into the interior through the gaps below and to the sides of the anchor bolt 50, and the installation is completed by placing it on each second anchoring plate 51 while inserting the two first anchor bolts 50A into the corresponding housing grooves 66, thus providing excellent ease of installation.

[0042] Furthermore, since the anchoring reinforcement member 60 is installed in a lower area slightly away from the area where the anchor bolts 50, stirrups 56, vertical reinforcements 55, and main reinforcements 25 of the foundation beam 20 are intertwined, the installation of the anchoring reinforcement member 60 does not cause further intertwining of the reinforcing bars inside the column-shaped foundation 10. As a result, the concrete forming the column-shaped foundation 10 can be spread throughout its entire area without gaps, making it possible to construct a high-quality column-shaped foundation 10.

[0043] Here, in addition to the configuration shown in Figure 3, the anchoring reinforcement member may also be an anchoring reinforcement member 60A, as shown in Figure 4, in which a reinforcing rib 67A that protrudes downward is attached only to the end face 62 with the receiving groove 66. Furthermore, although not shown, the anchoring reinforcement member 60A shown in Figure 4 may have additional reinforcing ribs that protrude downward on the other end face 63, or, unlike the configuration shown in Figure 4, a reinforcing rib that protrudes upward may be attached only to one end face 62, or to both end faces 62 and 63. Moreover, the configuration shown in Figure 3 may be modified by omitting the reinforcing rib 67 attached to the end face 63.

[0044] As shown in Figure 5, when the steel column 30 is displaced in the Y1 direction, which is the direction away from the foundation beam 20 (and therefore the direction in which both open up), due to the horizontal force acting during an earthquake, a compressive force C1 is generated in the column-shaped foundation 10, as shown in the figure, from the upper end on the side where the steel column 30 is leaning (upper left in the illustrated example) to the lower end in a diagonal direction (lower right in the illustrated example).

[0045] In the column-shaped foundation 10, a reinforcing anchoring member 60 having a bearing area A is provided in the direction of application of the compressive force C1. As a result, the entire area of ​​the reinforcing anchoring member 60 receives the bearing pressure q1 from above the column-shaped foundation 10, and the bearing pressure q1 (the sum of the distributed bearing pressures q1) can be effectively transmitted to each of the first anchor bolts 50A as an axial force N1, forming an effective compression strut that can resist the acting compressive force C1. In particular, since the second anchoring plate 51 and the reinforcing anchoring member 60 are arranged inside the column-shaped foundation 10 at a position below the lower end main reinforcement 25B of the foundation beam 20, a compression strut can be formed throughout the entire area of ​​the column-shaped foundation 10.

[0046] For comparison, if we consider a configuration without the anchoring reinforcement member 60, the bearing area receiving the bearing pressure is limited to the small area of ​​the second anchoring plate 51. As a result, the bearing pressure that can be transmitted to the first anchor bolt 50A is significantly smaller than the bearing pressure q1 shown in the figure.

[0047] Furthermore, when such a compressive force C1 is applied, as shown in Figure 2, the anchoring reinforcement member 60 is pushed out in the X direction toward the foundation beam 20. However, because the first anchor bolts 50A are housed in a receiving groove 66 that opens toward the foundation beam 20, the anchoring reinforcement member 60 engages with the two first anchor bolts 50A in a pressing state, and this engagement further enhances the transmission of bearing pressure from the anchoring reinforcement member 60 to the first anchor bolts 50A.

[0048] Furthermore, since the anchoring reinforcement member 60 receives bearing pressure that can counteract the compressive force C1 and transmits it to the first anchor bolt 50A, measures such as making the bottom surface of the column-shaped foundation protrude several centimeters below the bottom surface of the foundation beam, as in conventional structures, become unnecessary. As shown in the illustrated example, the bottom surfaces 12 and 22 of both the column-shaped foundation 10 and the foundation beam 20 can be constructed flush, resulting in even better constructability. In the illustrated example, the top surfaces 11 and 21 of both the foundation 10 and the foundation beam 20 are also constructed flush.

[0049] Next, with reference to Figures 6 to 8, modified examples of the exposed column base foundation structure according to the embodiment will be described. Here, Figure 6 is a longitudinal cross-sectional view of a modified example of the exposed column base foundation structure according to the embodiment, and Figure 7 is a view taken along the line VII-VII in Figure 6. Figure 8 is a diagram illustrating the force generated when the steel column is displaced in a direction that closes it to the foundation beam in the modified example of the exposed column base foundation structure according to the embodiment.

[0050] As shown in Figures 6 and 7, the exposed column base foundation structure 100A differs from the exposed column base foundation structure 100 shown in Figure 1, etc., in that, in addition to the anchoring reinforcement member 60 connecting the two first anchor bolts 50A, a separate anchoring reinforcement member 60 connects the other two second anchor bolts 50B.

[0051] As shown in Figure 5, the steel column 30 can be displaced not only in the direction away from the foundation beam 20, but also in the Y2 direction, which is the direction towards the foundation beam 20 (and therefore the direction in which both close together). When the steel column 30 is displaced in this way, a compressive force C2 is generated in the column-shaped foundation 10, as shown in the figure, from the upper end on the side where the steel column 30 is leaning (upper right in the illustrated example) to the lower end in the diagonal direction (lower left in the illustrated example).

[0052] In the exposed column base foundation structure 100A, a reinforcing member 60 having a bearing area A is provided in the direction of application of the compressive force C2. As a result, the entire area of ​​the reinforcing member 60 receives the bearing pressure q2 from above the column-shaped foundation body 10, and the bearing pressure q2 (the sum of the bearing pressures q2, which are distributed loads) can be effectively transmitted to the second anchor bolt 50B as an axial force N2, forming an effective compression strut that can counteract the acting compressive force C2.

[0053] In other words, effective compression struts are formed against both the compressive force C1 in the direction shown in Figure 5 and the compressive force C2 in the direction shown in Figure 8, allowing the structure to counteract both compressive forces C1 and C2.

[0054] Furthermore, according to the inventors' analysis, it has been determined that the compressive force C1 generated when the steel column 30 is displaced in the direction away from the foundation beam 20 (opening direction) is larger than the other compressive force C2. For this reason, as in the exposed column base foundation structure 100, a reinforcing anchoring member 60 connecting the first anchor bolts 50A on the foundation beam 20 side is made an essential component, and as in the exposed column base foundation structure 100A, a separate reinforcing anchoring member 60 connecting the second anchor bolts 50B is made an optional component.

[0055] Next, with reference to Figures 9 and 10, other modifications of the exposed column base foundation structure according to the embodiment will be described. Here, Figure 9 is a cross-sectional view of another modification of the exposed column base foundation structure according to the embodiment, and Figure 10 is a perspective view of yet another example of the anchoring reinforcement member.

[0056] The exposed column base foundation structure 100B differs from the exposed column base foundation structure 100A in that, instead of applying different anchoring reinforcement members 60 to the first anchor bolt 50A and the second anchor bolt 50B as shown in Figure 7, it has an anchoring reinforcement member 60B provided on a pair of end faces 64 and 65 of a common plate 61A, respectively, into which the first anchor bolt 50A and the second anchor bolt 50B fit, in which case the first anchor bolt 50A and the second anchor bolt 50B fit.

[0057] Even with the exposed column base foundation structure 100B to which the anchoring reinforcement member 60B is applied, just like with the exposed column base foundation structure 100A, it is possible to receive effective bearing pressures q1 and q2 for both compressive forces C1 and C2 in different directions and transmit them to the first anchor bolt 50A and the second anchor bolt 50B.

[0058] Furthermore, although not shown in the illustration, in Figure 9, even in a configuration where a separate foundation beam 20 is further fixed to other sides 13 of the column-shaped foundation 10 (for example, the upper side 13 or the lower side 13 in Figure 9), the common anchoring reinforcement member 60B spans all the anchor bolts 50 and connects them to each other. As a result, a portion of the plate 61A receives a bearing pressure that effectively counteracts the compressive force caused by the displacement of the steel column 30 in various directions, and transmits it to the anchor bolts 50.

[0059] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0060] 10: Column type foundation body 11: Top surface 12: Bottom 13: Side view 20: Foundation beam 21: Top surface 22: Bottom 23: End face 25: Main reinforcement 25A: Top main bar (main bar) 25B: Bottom main bar (main bar) 26: First fixing plate 27: Ribs 30: Steel column 31: Bottom edge 41: Base plate 45: Grout layer 50: Anchor bolts 50A: First anchor bolt (anchor bolt) 50B: Second anchor bolt (anchor bolt) 51: Second fixing plate 52: Nut 55: Standing muscles 56: Muscle tissue 60, 60A, 60B: Reinforcement members for the anchoring section 61, 61A: Plate 62, 63, 64, 65: End face 66: Containment groove 67, 67A: Reinforcement ribs 100,100A: Exposed column base foundation structure C1, C2: Compression force q1, q2: Support pressure A: Bearing area N1,N2: Axial force

Claims

1. An exposed column base foundation structure is characterized in which a base plate is placed directly or indirectly on a reinforced concrete column-shaped foundation, a steel column is fixed to the upper surface of the base plate, anchor bolts fixed to the base plate are embedded in the column-shaped foundation, a reinforced concrete foundation beam is fixed to the side of the column-shaped foundation, and a first anchoring plate at the end of the main reinforcement of the foundation beam is anchored to the column-shaped foundation, The aforementioned anchor bolt is provided with a second anchoring plate at its lower end, and the anchor bolt includes a plurality of first anchor bolts arranged on the foundation beam side and a plurality of second anchor bolts arranged on the opposite side of the foundation beam. A reinforcing member for the anchoring portion is provided, which connects multiple first anchor bolts to each other on the respective second anchoring plates. The aforementioned anchoring reinforcement member comprises a plate and a reinforcing rib perpendicular to the plate, which is fixed to a part of the end face of the plate. An exposed column base foundation structure characterized in that the end face of the plate is provided with a plurality of accommodating grooves into which a plurality of the first anchor bolts are fitted.

2. The exposed column base foundation structure according to claim 1, characterized in that the plurality of second anchor bolts are housed in the housing grooves of a separate anchoring reinforcement member and connected to one another.

3. An exposed column base foundation structure is characterized in which a base plate is placed directly or indirectly on a reinforced concrete column-shaped foundation, a steel column is fixed to the upper surface of the base plate, anchor bolts fixed to the base plate are embedded in the column-shaped foundation, a reinforced concrete foundation beam is fixed to the side of the column-shaped foundation, and a first anchoring plate at the end of the main reinforcement of the foundation beam is anchored to the column-shaped foundation, The aforementioned anchor bolt is provided with a second anchoring plate at its lower end, and the anchor bolt includes a plurality of first anchor bolts arranged on the foundation beam side and a plurality of second anchor bolts arranged on the opposite side of the foundation beam. A reinforcing member for the anchoring portion is provided, which connects multiple first anchor bolts to each other on the respective second anchoring plates. The aforementioned anchoring reinforcement member comprises a plate and a reinforcing rib perpendicular to the plate, which is fixed to a part of the end face of the plate. The exposed column base foundation structure according to claim 1, characterized in that the end face of the plate is provided with a plurality of accommodating grooves into which all of the plurality of first anchor bolts and second anchor bolts fit.

4. The exposed column base foundation structure according to any one of claims 1 to 3, characterized in that the second anchoring plate and the anchoring reinforcing member are arranged at a position below the lower end main reinforcement included in the anchored main reinforcement inside the column-shaped foundation.

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