JP2012077531A - Bar arrangement structure of upper steel structure column base foundation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bar arrangement structure of an upper steel structure column base foundation, capable of dissolving the excessively-concentrated bar arrangement of anchor bolts and various kinds of reinforcing bars, facilitating reinforcing bar assembly, and improving the reliability of the structure.SOLUTION: A column base foundation 3 of a reinforced concrete structure supports a steel column 2 in the upper structure 1 of the steel structure, and is provided with a rising part 3a to which a footing beam 5 of the reinforced concrete structure is joined or which is provided on a footing portion. In the rising part 3a, a plurality of anchor bolts 6 connected with the steel column 2 are buried, and a plurality of column main reinforcements 15 arranged side by side at the outer peripheral part and extended in the vertical direction respectively and hoops 16 as reinforcing bars are provided. In the bar arrangement structure, reinforcing bars with a diameter-enlarged head having a diameter-enlarged head part 15a are used for the column main reinforcements 15.

Description

  The present invention relates to a bar arrangement structure of an upper steel column base, which is a reinforcement structure of a column base for a steel upper structure such as a factory, a warehouse, or an office building.

  In factories, warehouses, office buildings, etc., the majority of superstructures are made of steel. Among them, as for the column base part that is a contact point between the upper structure and the lower foundation structure, the exposed fixed column base is often used to ensure reliability, workability, and construction period.

JP 2000-73381 A JP 2009-264045 A

In the above-described exposed fixed column base made of upper steel structure, for example, as shown in FIG. 10, a plurality of anchor bolts 51 are embedded, there are a large number of column main bars 52, hoops, and the like. In order to ensure the fixing length, a hook portion, an L-shaped portion, or the like is provided at the end portion of this (in the figure, only some column main bars 52 are shown, and other reinforcing bars are not shown). For example, in accordance with building laws and regulations, for the column main reinforcement 52 of the column base 50, the fixing length Lt of the lower part and the upper part is used in order to reliably transmit the tensile force to the foundation beam 53 and the footing part (not shown). For this reason, an L-shaped portion 52a of the column main reinforcement 52 and a hook portion (not shown) are provided. For this reason, the anchor bolt 51 and the reinforcing bar are congested excessively, which makes it difficult to assemble the reinforcing bar.

It should be noted that, in order to ensure the fixing length in the reinforcing bar, it is stipulated in construction laws and regulations that an enlarged head can be used, but the enlarged head is used for any part. This is not specified, and no example of using an enlarged head on the column base is known. As an example of bar arrangement using an enlarged head, there is one shown in Patent Document 2.

  An object of the present invention is to eliminate an overcrowded arrangement of anchor bolts and various reinforcing bars in an upper steel column base, thereby facilitating rebar assembly and improving the reliability of the structure. Is to provide a bar arrangement structure.

  The bar arrangement of the upper steel column base of the present invention is a reinforced concrete column base that supports the steel column in the steel upper structure, and the reinforced concrete base beam is joined or footed. A plurality of anchor bolts which are connected to the steel column are embedded in the rising part, and are arranged side by side on the outer peripheral part as reinforcing bars of the rising part. In the bar base foundation bar arrangement structure having a plurality of column main bars extending to the top and a plurality of upper and lower hoops surrounding the plurality of column main bars, an enlarged head at the end of the column main bars It is characterized by using a rebar with an enlarged head having a diameter.

  According to this configuration, since the reinforcing bar with an enlarged head having an enlarged head is used as the column main bar, the hook part and the L-shaped part at the end of the column main bar, which are necessary for securing the fixing length, are unnecessary. Become. An enlarged head is required instead of the hook and L-shaped part, but the enlarged head is extremely small compared to the hook and L-shaped part. Therefore, the arrangement of the reinforcing bars is alleviated as much as the hook part and the L-shaped part are omitted. Therefore, although it is a column base with multiple anchor bolts embedded and a large number of column main bars and hoops, over-bar arrangement is eliminated, rebar assembly is facilitated, fixing length is secured and The reliability of the structure can be improved by improving the construction accuracy.

In this invention, the column main reinforcements at the four corners of the column base are rebars with an enlarged head having enlarged heads at the upper and lower ends, and the intermediate column principal reinforcement is an enlarged head having an enlarged head only at the lower end. It is good also as a rebar with a part.
According to the laws and standards related to construction, in the fixed column base approved, the column main reinforcement of the column base is fixed at the lower part, and in the column main reinforcement at the corner, it is obliged to install a hook at the upper end. It has been. Therefore, the pillar main bars at the four corners are rebars with an enlarged head having enlarged heads at the upper and lower ends, so that the fixing length at the lower end and the requirement to provide a hook at the upper end are satisfied, and the middle column main reinforcement is at the lower end. By using a reinforcing bar with an enlarged head having an enlarged head only, the fixing length required for the lower end can be satisfied. Reinforcing bars that have an enlarged head at one end have been tried to commercialize standard items, and for intermediate column main reinforcing bars, it is a reinforcing bar with an enlarged head that has an enlarged head only at the lower end. A fixed-size object can be used, and processing costs and waste of rebars due to cutting can be eliminated, thereby reducing costs.

In the present invention, the column main reinforcements at the four corners of the column base may have L-shaped portions at the lower end that are bent outwardly of the column and extend substantially horizontally to form an L shape with the vertical portion. It is preferable that the upper ends of the columnar main bars at the four corners have the above-mentioned enlarged diameter head, but it is not always necessary to provide the enlarged diameter head.
Thus, when the column main reinforcements at the four corners of the column base have L-shaped portions extending outward from the columns, the L-shaped portions become the legs of the reinforcing bar assembly of the column main reinforcing bars and the hoops during the bar arrangement work. As a result, the rebar assembly is stabilized and workability is improved.

  In this invention, a reinforced concrete foundation beam is joined to the rising portion, and there is an end portion of the beam reinforcing bar of the basic beam in a portion surrounded by the plurality of column main bars and hoops of the rising portion, The beam main reinforcement may be a reinforcing bar with an enlarged head having the enlarged end at the end. As for the main beam of the beam, an overcrowded arrangement can be more reliably eliminated by setting the portion fixed in the column base as an enlarged head.

  The bar arrangement of the upper steel column base of the present invention is a reinforced concrete column base that supports the steel column in the steel upper structure, and the reinforced concrete base beam is joined or footed. A plurality of anchor bolts which are connected to the steel column are embedded in the rising part, and are arranged side by side on the outer peripheral part as reinforcing bars of the rising part. In the bar base foundation bar arrangement structure having a plurality of column main bars extending to the top and a plurality of upper and lower hoops surrounding the plurality of column main bars, an enlarged head at the end of the column main bars Because of the use of a rebar with an enlarged head with a diameter of the upper steel column base, the overcrowded arrangement of anchor bolts and various types of rebar is eliminated, rebar assembly is facilitated, and structural reliability is improved. It can be.

It is a fracture | rupture front view which shows the bar arrangement structure of the upper steel column-shaped foundation based on one Embodiment of this invention. It is a fracture | rupture top view which shows the bar arrangement of the same column base. It is the top view and front view of the anchor frame which assembled the anchor used for the column base. It is a front view which shows an example of the diameter expansion head of the column main reinforcement of the column base. It is a fracture | rupture front view which shows the modification of an enlarged diameter head. It is a fracture | rupture front view which shows the other modification of a diameter-expansion head. It is a fracture | rupture perspective view which shows the upper steel-frame column base based on other embodiment. It is a fracture | rupture front view which shows the reinforcing bar structure of the upper steel column base based on other embodiment. It is a partially-omission perspective view of the reinforcing bar assembly in the same embodiment. It is explanatory drawing which shows the fixing length in the reinforcement of the conventional column base.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2 are sectional views, but the hatching of the concrete portion is omitted. The bar arrangement of the upper steel column base is a reinforcement arrangement in the column base 3 of the reinforced concrete structure that supports the steel column 2 in the upper structure 1 of the steel structure. The steel column 2 is made of a square steel pipe or an H-shaped steel and has a base plate 4. The upper structure 1 is a factory, a warehouse, or an office building. The planar shape of the column base 3 is a rectangle such as a square in this embodiment, but may be a circle or the like.

  1 and 2, a reinforced concrete foundation beam 5 is joined to a column base 3 on one side surface or four side surfaces. 1 and 2 are examples in which the foundation beam 5 is joined to two side surfaces of the column base 3. FIG. 7 shows an example in which the foundation beam 5 is joined to the two side surfaces of the column base 3. However, FIG. 7 shows only a part of the reinforcing bars of the column base 3 and omits others.

  The column base 3 has a rising portion 3a having a width wider than the width of the foundation beam 5, and a footing portion (not shown) extending on the outer periphery of the lower end of the rising portion 3a. The footing unit is not necessarily provided. Moreover, the footing part is provided and the foundation beam 5 does not need to be provided. A plurality of anchor bolts 6 that are coupled to the steel column 2 are embedded in the column base 3. In the illustrated example, two anchor bolts 6 are provided side by side at the four corners of the column base 3. In FIG. 1, only one anchor bolt 6 is shown for one corner, and the others are omitted for convenience of illustration. The base plate 4 of the steel column 2 is installed on the upper surface of the column base 3 via the interposition member 7. The interposition member 7 is a top end mortar, a spacer, or the like. Anchor bolts 6 are inserted into the respective bolt insertion holes provided in the base plate 4, and the base plate 4 is fixed to the upper surface of the column base 3 by tightening nuts 9 screwed into the anchor bolts 6.

  The anchor bolts 6 may be individually embedded in the column base 3 or may be embedded in the column base 3 in the assembled state as the anchor frame 10 as shown in FIG. The anchor frame 10 inserts each anchor bolt 6 used for one column base 3 into insertion holes (not shown) provided in the upper and lower rectangular annular frames 11 and 12, and nuts 9 and 13 It is tightened. Legs 15 made of L-shaped steel or the like are provided at the four corners of the lower frame. The legs 15 may be omitted. The upper frame 11 may be embedded in the cocrete of the column base 3 or exposed upward, or may be removed after the concrete has hardened. A fixing plate 14 is attached to the lower part of each anchor bolt 6. The fixing plate 14 is also provided when each anchor bolt 6 is embedded individually. The outer periphery of each anchor bolt 6 may be covered with an unbonded sleeve (not shown) which is a sleeve for reducing friction with the foundation concrete.

1 and 2, the reinforcing bars of the rising portion 3a of the column base 3 are a plurality of column main bars 15 (15A, 15B) arranged side by side and extending in the vertical direction, And a plurality of upper and lower hoops 16 surrounding the column main reinforcement 15. The column main bars 15 include column main bars 15A arranged at the four corners of the column base 3 and column main bars 15B arranged in the middle between the column main bars 15A at the respective corners.
As the reinforcing bars of the foundation beam 5, a plurality of beam main bars 17 provided in a row in the horizontal direction at the upper end and the lower end, and a plurality of longitudinal stirrups 18 surrounding the periphery of the upper and lower beam main bars 17, It consists of a lateral auxiliary muscle 19.

Each of the column main bars 15 of the column base 3 is a reinforcing bar with an enlarged head having an enlarged head 15a at the end. Among these, the column main bars 15A arranged at the four corners have the enlarged heads 15a at the upper and lower ends, and the intermediate column main bars 15B have the enlarged heads 15a only at the lower ends.
As shown in FIG. 2, the beam main reinforcement 17 of the foundation beam 5 extends in the column base 3 and is fixed in the rising portion 3 a of the column base 3. Each of the beam main bars 17 has an end portion fixed on the column base 3 as an enlarged head portion 17a.

FIG. 4 shows an example of the enlarged head 15 a of the columnar main muscle 15. The diameter-enlarged head 15a in this example is obtained by plastically deforming the end of a reinforcing bar that becomes the columnar reinforcement 15 into an enlarged shape in a heated state. The outer diameter of the enlarged head 15a is set to an outer diameter determined by laws and regulations related to architecture. Further, the column main reinforcing bars 15 are deformed reinforcing bars provided with protrusions 15c on the outer periphery of the round bar portion 15b.
The enlarged head portion 15a of the columnar reinforcement 15 is not limited to one integrally formed by plastic deformation. For example, as shown in FIG. It may be fitted and joined to the end of the rod 15b. Further, as shown in FIG. 6, a male screw portion 15d may be formed on the outer periphery of the end portion of the columnar main bar 15, and a head forming member 21A having a female screw hole 21b may be screwed together to form the enlarged diameter head portion 15a.
Note that the enlarged head 17a of the beam main bar 17 in FIG. 2 is the same as the various enlarged heads 15a of the column main bar 15 described above.

According to the bar arrangement structure of the column base 3 having the above-described configuration, since the reinforcing bar with the enlarged head having the enlarged head 15a is used for the column main reinforcement 15, the end of the column main reinforcement necessary for securing the fixing length is used. The hook part and L-shaped part of the part become unnecessary. That is, the fixed length of the lower part of the column main reinforcement 15 of the column base 3 is determined in the fixed column base authorized by the laws and standards relating to architecture. Further, regarding the column main bar 15A at the protruding corner, the fixing length of the upper part is further determined, and it is obliged to provide a hook for that purpose.
On the other hand, in this embodiment, the columnar reinforcing bars 15A at the four corners are rebars with an enlarged head having enlarged heads 15a at both upper and lower ends, and the middle column reinforcing bar 15B is expanded only at the lower end. It is a reinforcing bar with an enlarged head having a radial head. By providing these enlarged diameter heads 15a, only the upper fixing length L1 and the lower fixing length L2 shown in FIG. 1 satisfy the standard for securing the fixing length and obtain the necessary fixing strength. be able to.
Although the enlarged diameter head 15a is necessary instead of the hook part and the L-shaped part, the enlarged diameter head 15a is extremely small as compared with the hook part and the L-shaped part.

For this reason, the overcrowding of the bar arrangement is alleviated as much as the hook part and the L-shaped part are omitted. Accordingly, although the anchor base 6 is embedded with a plurality of anchor bolts 6 and there are a large number of column main bars 15, hoops 16, anchor portions of the beam main bars 17, etc., the overcrowded arrangement is eliminated and the reinforcing bars Assembling becomes easy, and the reliability of the structure can be improved by securing the fixing length and improving the construction accuracy.
In this embodiment, the beam reinforcing bar 17 is also a reinforcing bar with an enlarged head having an enlarged head 17a as a portion fixed in the column base 3 so that an overcrowded reinforcing bar is secured while securing fixing strength. It is more reliably resolved.
Further, when the anchor frame 10 as shown in FIG. 3 is configured, there are connecting frames 11 and 12 and the members embedded in the concreas of the column base 3 are more densely packed. Since the enlarged diameter head 15a is provided, the overcrowded arrangement is alleviated, and the use of the anchor frame 10 and the enlarged diameter head 15a makes it possible to assemble the rebar more easily and in a short time, and further improve the reliability. .

8 and 9 show another embodiment of the present invention. In this embodiment, in the embodiment shown in FIG. 1, an L-shaped portion 15f is provided at the lower end instead of providing the enlarged head portion 15a at the lower end of the columnar reinforcing bars 15A at the four corners. The L-shaped portion 15f is bent from the lower end of the vertical portion of the column main bar 15A to the outside of the column and extends substantially horizontally to form an L shape with the vertical portion. The extending direction of the L-shaped portion 15f is, for example, an extension direction of a diagonal line in the cross section of the rising portion 3a of the column base 3 or a direction of approximately 45 ° with respect to any side surface of the rising portion 3a. The upper ends of the columnar main bars 15A at the four corners have the enlarged diameter head 15a, but the enlarged diameter head 15a is not necessarily provided. In FIG. 9, the intermediate column main reinforcement 15B is not shown.
As described above, when the columnar reinforcing bars 15A at the four corners have the L-shaped portions 15f extending outward from the columns, the L-shaped portions 15f serve as the legs of the reinforcing bar assembly of the columnar reinforcing bars 15 and the hoops 16 during the bar arrangement work. Functions and stabilizes the rebar assembly, improving workability. Other configurations and effects in this embodiment are the same as those in the first embodiment shown in FIG.

DESCRIPTION OF SYMBOLS 1 ... Upper structure 2 ... Steel column 3 ... Column base 5 ... Foundation beam 6 ... Anchor bolt 15 ... Column main reinforcement 15A ... Column main reinforcement 15B ... Middle column main reinforcement 15a ... Expanded head 15f ... L-shaped part 17 ... Beam main bar 17a ... Expanded head

Claims (4)

Reinforced concrete column base that supports the steel column in the superstructure of the steel frame, which has a rising part to which the reinforced concrete foundation beam is joined or provided on the footing part. , A plurality of anchor bolts to be connected to the steel column, and a plurality of column main bars that are arranged side by side on the outer periphery and extend in the vertical direction as the reinforcing bars of the rising portion, and the plurality of column main bars In the reinforcement structure of the column base with a plurality of upper and lower hoops surrounding the circumference of
A reinforcing bar structure for an upper steel column base with an enlarged head having an enlarged head at the end as the column main reinforcement.   In Claim 1, the column main reinforcement at the four corners of the column base is a reinforcing bar with an enlarged head having an enlarged head at the upper and lower ends, and the intermediate pillar main reinforcement has an enlarged head having an enlarged head only at the lower end. Reinforcement structure of upper steel column base with rebar with head.   In Claim 1, the column main reinforcements at the four corners of the column base are bent at the lower end of the column base, extend substantially horizontally, and have an L-shape with a vertical portion to form an L-shaped portion. Reinforcement structure. 4. The foundation beam according to claim 1, wherein a reinforced concrete foundation beam is joined to the rising portion, and the portion of the rising portion surrounded by the plurality of column main reinforcing bars and a hoop. There is an end portion of the beam main reinforcing bar, and the reinforcing structure of the upper steel column base is used as the reinforcing bar with the enlarged head having the enlarged end as the end portion.

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