JP2009144424A - Structure of bearing pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient and economical bearing pile resistant to bending moment by inexpensively connecting pieces of shape steel different in size. <P>SOLUTION: In this structure of the bearing pile, a pile body is inserted into a drilled hole 5 which is drilled in ground, and a hardening material such as mortar 6 and concrete is injected into the periphery of the pile body and hardened. The pile body 1 is constituted by connecting two or more types of pieces 2 and 3 of shape steel, different in the breadthwise sizes of a web W and a flange. A connecting plate 4 is interposed between the pieces 2 and 3 of shape steel, different in size, and end surfaces of the pieces of shape steel are connected to top and under surfaces of the connecting plate by butt welding, respectively. The efficient and economical bearing pile A is provided by using the thick high strength shape steel only for a portion undergoing the action of the great bending moment. Inexpensive construction can be performed by making the number of components smaller than in the case of the use of a splice plate etc. , and the load can be properly transferred in a vertical direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure of a support pile using a shape steel.

As support piles buried in the ground and supporting structures such as piers, those with various structures have been adopted.
In these support piles, as shown in the graph of FIG. 7, the bending moment does not act uniformly on the entire length of the pile, but a large bending moment acts on a part of the pile and the other part has a large moment. Does not work.
In general, the maximum value is reached by concentrated operation from near the surface of the pile to a certain depth, and almost no bending moment acts on the deeper part.
As shown in the graph of FIG. 7, the bending moment reaches the maximum value by 2 m from the ground surface, and when it reaches about 15 m, the bending moment does not act at all.
In other words, if a part of the pile has a strength capable of withstanding the bending moment, the other part may have a strength lower than that.

For steel pipe piles, etc., the diameter is the same, but the part where a large bending moment is applied is a thick steel pipe, and the part where the bending moment is small is a thin steel pipe. It is adopted that the steel pipe is changed to a thin steel pipe from the middle and inserted into the drilling hole as a pile body.
However, when adopting a shape steel such as H-shape steel or I-shape steel as a pile body, in order to change the thickness of the shape steel in order to change the strength, the shape steel is only a standardized one. At the same time as the thickness, the width of the flange and web will also change.
In order to connect shape steels of different sizes up and down, there arises a problem that a flange and a web in which a gap is generated due to the difference in size must be connected.
However, in the case of shape steel, butt welding between base materials and fillet welding between the base plate and base material are impossible as with ordinary welded joints, so welded joints according to normal specifications are impossible. .

In order to connect shape steels having different sizes as described above, for example, a joint using a bolt as shown in FIG. 8 may be considered.
This is a means in which an attachment plate c is attached to a flange and a web of a large upper section steel a and a small lower section steel b, which are base materials, and the bolt d is passed through and fixed by a nut e.
In this case, when the shape steel is different by one size, a gap of 25 mm is generated in the flange. Therefore, when the support bearing is used, it is necessary to sandwich the gap adjusting material f between the flanges.
If this is simply a support bearing that can withstand the bending moment by the proof strength of the bolt, the bending moment is generated in the bolt in the portion sandwiching the gap adjusting material f, and the bolt strength is extremely reduced. It is necessary to join.
However, in order to achieve friction welding, the base material a / b, the splicing plate c, and the gap adjusting material f are treated with friction joint surfaces on both the flange and the web (such as removal of the black skin of the steel material and generation of high-quality rust). ) Is required, which is considerably more expensive than ordinary bolted joints.
Moreover, since the difference in plate | board thickness is only about 1 mm in a web part, the adjustment with the clearance gap adjustment material f arises.
JP-A-9-296427

  The problem to be solved is to make it possible to manufacture a pile main body composed of a plurality of different shaped steels at low cost so as to withstand a large bending moment.

The structure of the support pile according to the present invention is a structure of a support pile in which a pile body is inserted into a drilled hole in the ground, and a hardening material such as mortar or concrete is injected and cured around the pile body,
The pile body consists of two or more types of steel with different web and flange width sizes,
A connecting plate is interposed between the shaped steels of different sizes, and the end surfaces of the shaped steel are fixed to the upper and lower surfaces of the connecting plate by welding.
In addition, the structure of another supporting pile according to the present invention is characterized in that two or more types of different shape steels are such that the shape steel positioned above is larger than the shape steel positioned below. To do.

The structure of the support pile concerning this invention consists of the above structures, and can obtain the following effects.
<a> In order to ensure the strength of the part where a large bending moment acts, it is necessary to use a shape steel having a large size, that is, a thick part, and a part having a relatively thin thickness to the other part. Economical design and construction is possible by securing the necessary strength only for the parts and making the other parts inexpensive.
<B> A connecting plate is interposed between the upper shape steel and the lower shape steel, and the end of the shape steel is welded to this connecting plate. They can be connected without the need for an adjusting plate, so that a large bending moment is concentrated on the bolt and the bolt does not break.
<C> A connecting plate is interposed between different shaped steels, and the steel is welded to this connecting plate. Since there is no meat welding, the welding amount is reduced by the difference between fillet welding and butt welding, and a support pile can be manufactured at an inexpensive cost that is the same as that of a normal welded joint.
<D> Since the connecting plate is connected by interposing between the upper and lower steel shapes, the load in the vertical direction is transmitted more efficiently than when using an attachment plate, etc., and the moment generated in the connecting plate is minimized. .
<E> Since neither an attachment plate nor a gap adjusting plate is used, it is not necessary to reduce the number of members to achieve friction bonding, and the manufacturing cost does not become extremely high.
<F> A large shape steel is arranged as the upper shape steel, a small shape steel is arranged as the lower shape steel, and the strength of the portion near the ground surface of the pile body is increased, so that it is close to the normal ground surface. It is possible to make an efficient structure as a support pile in which a large bending moment acts.

  In the structure of the support pile according to the present invention, a connecting plate is interposed between different shape steels, and the end surfaces of the upper and lower steel shapes are butt welded to the connecting plate.

  FIG. 6 is an explanatory view of a pier in which the structure of the support pile according to the present invention is implemented.

<a> Pile main body The pile main body 1 is obtained by connecting a plurality of different shaped steel shapes in the vertical direction.
1-4 show that the upper H-section steel 2 is larger in both the web width size W1 and W2 and the flange size than the lower H-section steel 3. FIG.
Also, the thickness of the large-sized steel 2 is about several millimeters thicker than the small-sized steel 3.
A connecting plate 4 is interposed between the upper H-section steel 2 and the lower H-section steel 3, and the lower end surface of the upper H-section steel and the upper end surface of the lower H-section steel are butted against the upper and lower surfaces, respectively. Fix by welding.
Actually, in the factory, the connecting plate 4 is welded and fixed to either the upper or lower H-section steel 2 or 3, and the other H-shaped steel is welded and fixed at the site. There are the above merits.
The pile main body 1 is constituted by the upper H-section steel 2, the connection plate 4 and the lower H-section steel 3 as described above, but when the length of the pile main body 1 is further increased, the connection plate 4 is further interposed. Then, the shape steel may be fixed by welding.

<B> Insertion into the drilling hole The drilling hole 5 is excavated in the ground, and the pile body 1 is inserted therein.
First, the lower H-shaped steel 3 fixed to the upper end of the connecting plate 4 is suspended and inserted. When the insertion is completed to some extent, the upper H-shaped steel 2 is raised on the connecting plate 4 and the lower end surface is connected to the connecting plate. The upper surface of 4 is fixed by welding.
Thereafter, the pile body 1 is suspended to a predetermined depth, and the mortar 6 and concrete are injected into the drilling hole 5 to complete the support pile A.

<C> Construction of the pier A pier is constructed on the support piles A constructed as described above.

<E> Other configurations In the normal support pile A, the largest bending moment acts on the portion near the ground surface, and when the depth is usually several meters deep, the bending moment becomes almost zero. Usually, it is increased and the size of the lower section 3 is reduced.
However, in the present invention, a shape steel having a large size may be used in a portion where the acting bending moment is expected to be large. As shown in FIG. May be larger.

Explanatory drawing of the support pile of the present invention Perspective view before assembling pile body Side view of the connecting part of the pile body Top view of the pile body Side view of another pile body embodiment Explanatory drawing of the pier which implemented the structure of the support pile of the present invention Graph of bending moment acting on support pile Side view of connecting parts of different sizes of structural steel using splice plates

Explanation of symbols

A: Support pile 1: Pile body 2: Shape steel 3: Shape steel 4: Connection plate 5: Drilling hole 6: Mortar

Claims (2)

It is a structure of a support pile that inserts a pile body into a drilled hole in the ground and injects a hardening material such as mortar or concrete around it to harden it,
The pile body consists of two or more types of steel with different web and flange width sizes,
A structure of supporting piles in which connecting plates are interposed between different sizes of shaped steel, and the end faces of the shaped steel are fixed to the upper and lower surfaces of the connecting plates by welding. The structure of the support pile according to claim 1, wherein two or more types of different shape steels are configured such that the shape steel positioned above is larger than the shape steel positioned below.

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