JP2024042737A - Integration method of pile body and steel column, and integrated structure of pile body and steel column - Google Patents

Abstract

[Problem] The foundation construction process is long and expensive.
[Solution] A step of excavating a hole H in the ground G, a step of inserting the pile body 1 into the excavated hole H and burying it in the ground G, and a step of making a plurality of anchor bolts 3, 3a... project their upper ends. The step of constructing the independent foundation 2 installed on the upper end of the pile body 1, and passing the protruding ends of the anchor bolts 3, 3a... into the bolt insertion holes 6, 6a... formed in the base plate 5 of the steel column 4. This is a construction method for integrating the pile body 1 and the steel column 4, which includes the step of erecting the steel column 4 on the top surface of the independent foundation 2 by screwing nuts 7, 7a... In the reinforcement work in the construction process, a plurality of hoop reinforcements are placed at the overlap site between the plurality of pile cap reinforcing bars 8, 8a... provided at the upper end of the pile body 1 and the lower ends of the anchor bolts 3, 3a... By arranging reinforcement for 9, 9a, etc., underground beams are no longer required, and the foundation frame itself can be significantly reduced, and the amount of soil remaining during foundation construction can be significantly reduced, and the construction period can be shortened. Enables reduction of total construction costs.
[Selection diagram] Figure 1

Description

The present invention relates to a construction method and structure that integrates a pile body supporting an independent foundation and a steel column erected on the independent foundation.

Traditionally, an independent foundation is constructed on the top of a pile buried in the ground, and an overhead structure is constructed on this independent foundation, but in this construction method, the bending moment is reduced by underground beams that connect adjacent foundations. (For example, see Patent Document 1).

The above-mentioned pile supports the weight and also resists horizontal force during an earthquake, and at this time, the pile head of the pile also follows the horizontal movement of the steel column, resulting in bending moment and shear force.

The upper structure here is constructed using a seismic isolation device, but if a steel column is to be erected on an independent foundation, the bolt insertion hole in the base plate of the steel column should be Generally, a steel column is erected on the upper surface of an independent foundation by passing the protruding end of an anchor bolt whose lower end is buried in the foundation and screwing a nut thereon.

JP 2001-241050 A

However, with the above-mentioned conventional technology, construction work for constructing foundations and underground beams involves many steps such as excavation, concrete concrete, reinforcing, formwork, concrete pouring, formwork removal, and backfilling. There were issues that needed to be resolved, such as a long construction period and high construction costs.

In view of the problem that the foundation construction process is long and expensive based on the above-mentioned conventional technology, the present invention provides the following steps: a step of constructing an independent foundation on the upper end of the pile body, in which a plurality of anchor bolts are installed with their upper ends protruding; and a step of penetrating the protruding ends of the anchor bolts into bolt insertion holes formed in the base plate of the steel column. This is a method of integrating a pile body and a steel column, which includes the process of screwing nuts and erecting a steel column on the top surface of an independent foundation. By arranging a plurality of hoop reinforcements at the overlap site between the plurality of pile cap reinforcing bars provided at the upper end and the lower end of the anchor bolt, underground beams are not required. In this way, the above-mentioned problems can be solved by significantly reducing the foundation structure itself, greatly reducing the amount of soil remaining during foundation construction, and shortening the construction period, thereby making it possible to reduce the total construction cost.

In short, the present invention includes a step of drilling a hole in the ground, a step of inserting a pile body into the drilled hole and burying it in the ground, and an independent foundation on which a plurality of anchor bolts are installed with their upper ends protruding. The step of constructing the pile body on the upper end of the pile body, passing the protruding end of the anchor bolt through the bolt insertion hole formed in the base plate of the steel column, screwing the nut, and erecting the steel column on the top surface of the independent foundation. A construction method for integrating a pile body and a steel column, which includes a process in which a plurality of pile head reinforcing bars provided at the upper end of the pile body and the anchor bolts are installed in the reinforcement work in the construction process of an independent foundation. Since multiple hoop reinforcements are arranged at the overlapped part with the lower end, by eliminating the need for underground beams, basically the minimum required for drilling and independent foundation construction is minimized. Since only the soil can be removed, the amount of soil remaining when constructing an independent foundation can be reduced, reducing the amount of waste disposal and reducing the impact on the environment. Although it is time consuming, the foundation structure itself can be significantly reduced, the overall construction period can be shortened, and the total construction cost can therefore be reduced.
Then, by placing the pile cap reinforcing bars installed at the upper end of the pile body in a space surrounded by anchor bolts that fix the steel column and have multiple hoop bars arranged, an independent foundation can be constructed. , it is possible to cope with the column foot moment of an independent foundation without an underground beam using only the pile body.

Anchor bolts and pile cap reinforcing bars are overlapped over the required anchoring length or more, and hoop bars are provided to encompass them, so the binding effect of the concrete within the hoop bars prevents the anchor bolts and pile cap reinforcing bars from collapsing. It is possible to transmit stress directly and ensure reliability, and therefore it is possible to omit underground beams as in the conventional technology.Furthermore, the foundation bottom of the independent foundation is made by adding the necessary cover thickness to the above-mentioned anchorage length. Since all that is required is the dimensions, it is possible to make the foundation shallower, and the independent foundation can be made more compact, thereby reducing the construction effort.

Furthermore, as shown in Fig. 5, the conventional independent foundation has a foundation plate b built on the upper end of the pile a to which the pile cap reinforcing bars are fixed, and an anchor bolt of the steel column c located on the upper part of the foundation plate b. It is common to have a column type e that fixes the column type e, the reinforcement of the column type e is fixed to the foundation plate b, and a steel column c is erected on the top of the column type e. Therefore, the amount of concrete, formwork, and reinforcement tends to increase, and the stress of the steel column C is transferred to the column type e due to the anchor bolt d, and the stress of the column type e is transferred to the foundation plate b. Since the stress of b is sequentially transmitted to pile a by the pile cap reinforcing bars, the stress transmission path is long and the efficiency is poor, and furthermore, multiple piles a are placed against the independent foundation. For example, since the steel column c is no longer placed directly above the pile a, the stress transmission path becomes complicated, but according to the present invention, the stress between the anchor bolt and the pile head reinforcement in one pile body is reduced. Since the stress is directly transmitted, the stress transmission path is short and the transmission efficiency can be improved.Also, since the independent foundation can be used even if it is a rectangular parallelepiped, the amount of concrete, formwork, and reinforcement can be reduced. It is possible to aim for
Although not shown in Fig. 5, it is common practice to improve the integrity of pile a and foundation b by constructing an independent foundation with the upper end of pile a digging into foundation b. However, according to the present invention, the pile head reinforcing bars that are integrated with the pile body, and the reinforcement and anchor bolts on the independent foundation side are made of cast-in-place concrete. Since the pile body and the independent foundation can be integrated together, the practical effects are enormous, such as the ability to further integrate the pile body and the independent foundation.

FIG. 2 is a sectional view showing an integrated structure of a pile body and a steel column according to the present invention. FIG. 2 is a partially sectional plan view of the integrated structure of the pile body and steel column in FIG. 1. FIG. It is a sectional view showing a ground hole drilling process. It is a sectional view showing a process of inserting a pile body into an excavation hole. It is a sectional view showing a state after construction of an independent foundation. FIG. 2 is a sectional view showing a state in which steel columns are erected on an independent foundation. This is a cross-sectional view of the overlapping portion of the anchor bolt and the pile head reinforcement, which forms a polygonal hoop reinforcement. FIG. 3 is a cross-sectional view of the overlapping region of the anchor bolt and the pile cap reinforcing bars, where the hoop bars are circular. It is a sectional view showing a state in which a steel frame column is erected on a conventional independent foundation.

The integrated structure of a pile body and a steel column according to the present invention basically includes a pile body 1 inserted into a hole H drilled in the ground G and buried in the ground G; An independent foundation 2 constructed at the upper end, and a plurality of anchor bolts 3, 3a... whose lower ends are buried in the independent foundation 2, projecting ends from the upper surface of the independent foundation 2 to the bolts of the base plate 5 at the lower end of the steel column 4. A steel column 4 is erected on the upper surface of the independent foundation 2 by passing through the insertion holes 6, 6a, and screwing nuts 7, 7a.

The upper ends of multiple pile head reinforcements 8, 8a... provided at the upper end of the pile body 1 are arranged in the space surrounded by the anchor bolts 3, 3a..., and multiple hoop reinforcements 9, 9a... are arranged outside the overlapping areas of the anchor bolts 3, 3a... and the pile head reinforcements 8, 8a....

Figure 1 is a cross-sectional view showing the integrated structure of a pile body and a steel column according to the present invention, and Figure 2 is a partial cross-sectional plan view of the integrated structure of the pile body and the steel column in Figure 1. The pile body 1 is a prefabricated pile made of reinforced concrete, and multiple pile head reinforcing bars 8, 8a... are installed at regular intervals around the upper end.

The independent foundation 2 is formed in the shape of a rectangular parallelepiped, the upper and lower surfaces are wider than the cross-sectional area of the pile body 1 and the steel column 4, and the upper ends of the four anchor bolts 3, 3a, 3b, and 3c protrude from the upper surface of the independent foundation 2. The upper ends of the pile head reinforcing bars 8, 8a... are arranged in the space surrounded by the lower ends of the anchor bolts 3, 3a, 3b, 3c buried in the independent foundation 2, and the anchor bolts 3, 3a, A plurality of hoop reinforcements 9, 9a... are arranged at predetermined intervals in the vertical direction at the lower ends of 3b and 3c.

In other words, the overlapping parts of the pile head reinforcing bars 8, 8a... of the pile body 1 and the lower ends of the anchor bolts 3, 3a, 3b, 3c that fix the steel column 4 to the independent foundation 2 are , 3b, 3c are surrounded by hoop reinforcements 9, 9a, etc., and the concrete forming the independent foundation 2 enhances mutual integrity, thereby improving the integrity of the pile body 1 and the steel column 4.

Next, the method of integrating an upper structure and a pile body according to the present invention will be explained based on FIGS. 3(a) to 3(d).
(1) While digging the ground G, a hole H of a predetermined depth is excavated and filled with cement milk M (see FIG. 3(a)).
(2) Insert the pile body 1 into the hole H (see FIG. 3(b)).
(3) Assemble the formwork (not shown) for the independent foundation 2, and attach the four anchor bolts 3, 3a, 3b, and 3c that fix the steel column 4 so that their upper ends protrude from the top surface of the independent foundation 2. installed, and a plurality of hoop reinforcements 9 are provided at the overlapped portions of the plurality of pile cap reinforcing bars 8, 8a... provided at the upper end of the pile body 1 and the lower ends of the anchor bolts 3, 3a, 3b, 3c, After performing reinforcement work including fixing 9a... at equal intervals in the vertical direction, concrete is poured into the formwork, and after curing and hardening, the formwork is removed and independent foundation 2 is constructed ( (See Figure 3(c)).
(4) A steel column 4 is erected on the top surface of the independent foundation 2 with a column bottom leveling mortar (non-shrinkage mortar) layer 10 interposed therebetween, and bolt insertion holes 6, 6a formed in the base plate 5 of the steel column 4, The protruding ends of anchor bolts 3, 3a, 3b, 3c are passed through 6b, 6c, nuts 7, 7a, 7b, 7c are screwed and fastened, and the steel column 4 is erected on the independent foundation 2 (Fig. 3 ( d)).

In the first embodiment, the number of anchor bolts 3, 3a, . . . is four, but the number is not limited to four, such as eight or twelve.

In addition, in the above-mentioned first embodiment, the pile body 1 is a prefabricated pile made of reinforced concrete, but it is not limited to a prefabricated pile made of reinforced concrete, and may be a prefabricated pile made of steel pipe, for example.
Furthermore, the pile body 1 does not have to be a prefabricated pile, but may be, for example, made of cast-in-place concrete, or may be a ground improvement pile that is buried in the ground G by drilling a hole in the original ground G while stirring and mixing the soil in the hole with a ground solidification material such as cement milk that is poured into the hole, excavating it to a predetermined length, and then placing reinforcing bars as necessary, and forming the pile by solidifying the ground solidification material.

Furthermore, although the shape of the hoop reinforcements 9, 9a, etc. in Example 1 is square, due to the relationship between the size of the steel column 4 and the diameter of the pile body 1, the anchor bolts 3, 3a, ... and the pile cap reinforcing bars 8, Since the relationship between the inside and outside of the respective envelopes of 8a... is not determined, the shape of the hoop lines 9, 9a... will also be as shown in Figure 2 if the envelopes of the anchor bolts 3, 3a... are larger. If it is a rectangle, it is a circle as shown in FIG. 4(b), and if the size is the same, it is a polygon as shown in FIG. 4(a).

In addition, in order to arrange the hoop reinforcement 9, 9a..., or because the spacing between the anchor bolts 3, 3a... and the pile head reinforcement 8, 8a... is large, axial reinforcement (not shown) may be provided parallel to the anchor bolts 3, 3a... and the pile head reinforcement 8, 8a... to narrow the spacing and increase the restraining effect of the concrete in the hoop reinforcement 9, 9a....

1 Pile body 2 Independent foundation 3, 3a... Anchor bolt 4 Steel column 5 Base plate 6, 6a... Bolt insertion hole 7, 7a... Nut 8, 8a... Pile cap reinforcing bar 9, 9a... Hoop bar G Ground H Hole M Cement milk

Claims (2)

A process of drilling a hole in the ground, a process of inserting a pile body into the excavated hole and burying it in the ground, and a process of installing an independent foundation with a plurality of anchor bolts with their upper ends protruding at the top end of the pile body. A pile comprising the steps of constructing the steel column, and erecting the steel column on the upper surface of an independent foundation by passing the protruding end of the anchor bolt through a bolt insertion hole formed in a base plate of the steel column and screwing a nut. It is a construction method that integrates the body and the steel column,
In the reinforcement work in the independent foundation construction process, multiple hoop reinforcements are placed at the overlap site between the multiple pile cap reinforcing bars provided at the upper end of the pile body and the lower end of the anchor bolt. A construction method that integrates the pile body and steel column. An independent foundation is constructed at the upper end of the pile body buried in the ground, and the protruding end of the anchor bolt buried in the independent foundation is passed through the bolt insertion hole of the base plate at the lower end of the steel column, and a nut is screwed and fastened to create an independent foundation. A steel column is erected on the top surface, and a plurality of hoop reinforcements are arranged at the overlap site between the plurality of pile cap reinforcing bars provided at the upper end of the pile body and the lower end of the anchor bolt. An integrated structure of a pile body and a steel column.

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