JP2006265999A - Basic structure of independent pile without basic beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a basic structure of an independent pile, without a basic beam connecting a pile head with a connection beam firmly, while absorbing misalignment of a plurality of piles in a basic construction method of connecting the pile head applied to additionally build a superstructure at an upper part by avoiding existing facilities, such as a platform of a railway station and eliminating the basic beam by connecting a plurality of the pile heads with the connection beam. <P>SOLUTION: The pile heads 11a of four driven steel piles 11 are cut with their heights uniformed, and a steel cap 13 with a top end plate 12 is welded to the pile head 11a; a top end part of the connection beam 14 is placed on the top end plate 12; a lower end of a connection bolt 16 inserted into a through hole 15 with a gap is screwed to a lower nut 16a; and an upper end of the connection bolt 16 is passed through a blocking plate 17 blocking an upper opening of the through hole 15 and is screwed and fastened to an upper nut 16b, so that the top end of the connection beam 14 is fixed to the steel pile 11. The gap between the through hole 15 and the connection bolt 16 is filled with a filling material 18. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an independent pile foundation structure for a structure such as a building.

  Conventionally, as shown in the plan view of FIG. 11 and the elevation view of FIG. 12, the independent pile foundation method for a building is provided with a concrete footing 2 on the head of the pile 1 that has been placed, and the adjacent footings are used as a foundation. By connecting and integrating with the beam 3, the axial force, bending moment and shearing force transmitted from the column base 4 installed on the footing 2 were resisted.

  However, as shown in FIG. 13, even when the pillar 6 is erected, the existing beam A is obstructed by the existing facility A, as in the case where the existing building A such as the platform of the railway station is avoided and the upper building 5 is added to the upper part. Could not be provided. In such a case, for example, a construction method has been developed in which the lower end portion 6a of the column 6 is directly embedded in a thick on-site concrete pile 7 so as to resist the stress transmitted from the column 6 by forming an integral frame. It was.

Note that there are Patent Documents 1 and 2 as prior art documents related to the present invention. The invention of Patent Document 1 relates to a semi-fixed direct foundation and a pile foundation structure of a steel column using a steel beam. The invention of Patent Document 2 relates to a coupling structure of an upper structure and a foundation pile that couples a steel column and a foundation pile via a support hardware or the like.
JP 2002-121747 A JP 2002-146800 A

  However, the construction method and burial method for constructing the above-mentioned piles require processing of the remaining soil to be excavated, and the construction equipment becomes large, so existing platforms such as railway station platforms that are often constructed in confined spaces There was a problem in terms of environment, cost, and labor in the extension work of the shed at the facility.

  The present invention is applied to, for example, an extension of a shed on an upper part of an existing facility such as a railway station platform, and a pile head that eliminates the need for a foundation beam by connecting a plurality of pile heads with connecting beams. In the connection foundation method, it is providing the independent pile foundation structure without the foundation beam which can connect a pile head and a connection beam firmly, absorbing the misalignment of a some pile.

  The invention according to claim 1 of the present invention is an independent pile foundation structure having no foundation beam formed by connecting pile heads of a plurality of piles placed with a connection beam, and a top end plate provided on the pile head. On the top, a connecting plate having a through hole through which the connecting bolt is inserted with a gap is installed, and a closing plate for closing the top end plate and the upper opening of the through hole with the connecting bolt inserted through the through hole The independent pile foundation structure without a foundation beam is characterized in that the leading end of the connection beam is clamped by tightening and the gap around the connection bolt in the through hole is filled with a filler.

  The present invention is effectively applied when, for example, an existing facility such as a platform of a railway station is avoided and a shed is added to the upper part thereof, and a plurality of pile heads are connected by connecting beams, thereby eliminating the need for a foundation beam. In the pile head connection foundation construction method to perform, for example, as shown in FIGS. 1 to 3, the pile head and the connection beam can be firmly connected while absorbing misalignment of a plurality of piles. Since the inner diameter of the through hole at the tip of the connecting beam is sufficiently larger than the outer diameter of the connecting bolt, the connecting bolt can be passed through the through hole even if the pile core is displaced. In addition, the end of the connecting beam is sandwiched between the top end plate and the closing plate located above and below the through hole, and tightened with the connecting bolt and nut. A structure is obtained. A steel cap made of a steel pipe with a top end plate or the like may be attached to the pile head by welding, or the top end plate may be directly attached to the pile head by welding.

  When it is desired to reduce the amount of the filler filled in the through hole, for example, as shown in FIG. 4, a steel pipe having, for example, about half the inner diameter of the through hole is inserted into the through hole, and the inside of the inner tube is inserted. It is possible to fill the filler only in the gap in the inner intubation through the connecting bolt. Even when this internal intubation is used, the error absorption capacity of the center misalignment of the pile does not change and when the internal intubation is not used, there is an advantage that the triaxial restraint state is increased by the internal intubation and the bearing strength of the filler is increased is there.

  As the pile, a steel pile or a synthetic pile of steel pipe and the like can be used. In addition, for example, as shown in FIG. 7, a steel pipe pile with a screw (with blades) can be used. In this case, the screw also serves as an anchor, so that it resists the pulling force of the pile that easily occurs during an earthquake. There is an advantage that there is no residual soil, and no large-scale equipment for placing concrete is required.

  The invention according to claim 2 of the present invention is the independent pile foundation structure according to claim 1, wherein a stiffening beam that connects the ends of adjacent connecting beams is provided, and the connecting beam and the stiffening beam are joined. It is an independent pile foundation structure without foundation beams characterized by

  The independent pile foundation of the present invention is a plurality of piles, for example, as shown in FIG. 5, in which four pile heads are connected with a cross-shaped connecting beam in plan view, and the tip of the connecting beam in an adjacent pile Connect the parts with stiffening beams. As shown in FIGS. 5 and 6, when the material core (material axis) of the connecting beam does not match the pile core, an eccentric moment M, which is the product of the axial force N and the eccentric amount E, acts on the pile. However, the eccentric moment is distributed to the two stiffening beams rigidly joined to the tip of the connecting beam so as not to be transmitted to the pile. The connecting beam and the stiffening beam are not limited to a rigid connection, and may be a bolt connection or the like.

  The invention according to claim 3 of the present invention is the independent pile foundation structure according to any one of claim 1 or claim 2, wherein the connecting beam is provided with a horizontal displacement suppression key. It is an independent pile foundation structure without beams.

  Since the independent pile foundation of the present invention has no underground beam, horizontal movement of the column base of the ground frame column is likely to occur during an earthquake. For example, as shown in FIG. Projecting into the ground from the crossing of the connecting beam underneath, increases the resistance to horizontal movement.

  The invention according to claim 4 of the present invention is the independent pile foundation structure according to any one of claims 1 to 3, wherein the ground around the pile is improved. There is no independent pile foundation structure.

  For example, as shown in FIG. 9, the ground improvement body by a soil cement column etc. is formed around a pile, and the horizontal movement of a column base part is suppressed by the horizontal resistance force of a ground improvement body.

  The invention according to claim 5 of the present invention is characterized in that, in the independent pile foundation structure according to any one of claims 1 to 4, a vibration suppressing device is incorporated in the ground frame. It is an independent pile foundation structure without foundation beams.

  For example, as shown in FIG. 10, the vibration suppressor suppresses the shaking of the building, reduces the force acting on the foundation, and suppresses the horizontal movement of the column base.

Since the independent pile foundation structure without a foundation beam of the present invention is configured as described above, the following effects can be obtained.
(1) When placing a pile, a pile misalignment of about several tens of millimeters may occur, but the connecting beam and the pile head are connected by a connecting bolt inserted through the through hole of the connecting beam, It can absorb large pile core errors, has a strong joint structure in which the end of the connecting beam is sandwiched between the top plate and the closing plate, and is tightened with connecting bolts and nuts, and a stiffening beam is provided. Thus, it is easy to handle the eccentric moment generated by the pile misalignment.
(2) Therefore, it is easy to manufacture and manage the foundation.
(3) In addition, since high accuracy is not required, it is possible to manufacture members such as connecting beams in advance before actually measuring the pile core position, which makes it possible to improve the efficiency of construction and reduce costs.
(4) If the horizontal displacement control key, ground improvement or vibration control device for ground frame are used together, the horizontal movement of the column base can be suppressed even in the ground where excessive deformation of the pile is likely to occur.
(5) By using a steel pipe pile with a screw, the pulling force can be resisted and the pulling force can be smoothly transmitted from the connecting beam to the pile, so that it is not necessary to widen the pile interval.
(6) Use of steel pipe piles with screws eliminates the need for residual soil treatment and does not require large construction equipment, which is advantageous in terms of environment, cost, and labor.
(7) Since the construction period can be shortened compared to the conventional construction method, it is particularly effective when construction can only be performed at night, such as the extension of a shed on a railway station platform.

  Hereinafter, the present invention will be described based on the illustrated embodiments. 1 to 4 show a basic first embodiment of the independent pile foundation structure of the present invention. 5 and 6 show a second embodiment in which a stiffening member is added. FIG. 7 shows a third embodiment using a pile with a screw. FIG. 8 shows a fourth embodiment in which a horizontal displacement suppressing member is added. FIG. 9 is a fifth embodiment in which a ground improvement body is added to a pile. FIG. 10 shows a sixth embodiment in which a vibration suppressing device is added to the ground frame.

[First Embodiment]
As shown in the plan view of FIG. 1, the elevation view of FIG. 2, and the partially enlarged cross-sectional view of FIG. 3, first, the pile heads 11 a of the four steel piles 11 that have been laid are cut at the same height. Then, a steel cap 13 made of a steel pipe or the like with the top end plate 12 attached to the top is attached on the pile head 11a by field welding. Only the top end plate 12 may be directly welded to the pile head 11a.

  A through hole 15 is provided by a steel pipe or the like at both ends of the connecting beam 14 made of H-shaped steel or the like, and this tip is placed on the top end plate 12, and the steel cap 13 and the connecting beam 14 are placed. Are connected using a connecting bolt 16. As shown in FIG. 3, for example, this connection method is such that, for example, the lower end of the connection bolt 16 is screwed to the lower nut 16a attached to the lower surface of the top end plate 12 by factory welding, and the upper end of the connection bolt 16 is passed through the through hole. A closing plate 17 that closes the upper opening of 15 is passed through and screwed to the upper nut 16b. The upper nut 16b is sufficiently tightened to firmly close the through hole 15 from above and below. The distal end portion of the connecting beam 14 is sandwiched between the top end plate 12 and the closing plate 17 and is tightly coupled to the pile head of the steel pile 11.

  Since the inner diameter of the through hole 15 is sufficiently larger than the outer diameter of the connecting bolt 16, a filler (non-shrink mortar, etc.) 18 is filled from the filler injection hole 18a into the gap between the through hole 15 and the connecting bolt 16. To do. It is confirmed that the filler 18 is completely filled by the air holes 18 b provided in the closing plate 17.

  Further, when the through hole 15 has a large inner diameter, a large amount of filler 18 is required. In such a case, as shown in FIG. A steel pipe 19 having a diameter about half the inner diameter of the hole 15 is inserted, and only the gap between the inner pipe 19 and the connecting bolt 16 is filled with the filler 18. A bottom plate 19 a is provided below the inner intubation 19 so that an axial force acting on the inner intubation 19 can be transmitted to the top end plate 12. The bottom plate 19a is an eccentric plate, and can correspond to various pile core positions by rotating. The bolt through hole of the closing plate 17 is a long hole 17a so that it can correspond to various pile core positions. The long hole 17a is closed with a washer.

  As described above, the four steel piles 11 are connected in a cross shape by the connecting beam 14 (see FIG. 1). The arrangement and number of steel piles 11 to be connected are not limited to this, and various modes are conceivable. The column base 4 is joined to the intersection of the connecting beams 14. Moreover, the connection beam 14 is a bracket system, and the connection beam on the column base side and the connection beam on the pile side are bolted together via a splice plate.

  Thus, since the steel pile 11 is connected by the some connecting beam 14, the bending moment from the column base part 4 is processed by the strut of the steel pile 11, and it is four with respect to horizontal forces, such as an earthquake, for example. Therefore, even if there is no foundation beam as in the past, it can be established as an independent pile foundation.

  As shown in FIG. 3, the steel cap 13 of the steel pile 11 and the connecting beam 14 are joined because the inner diameter of the through hole 15 of the connecting beam 14 has a sufficient dimension with respect to the thickness of the connecting bolt 16. Even if the core of the steel pile 11 is slightly displaced, the connecting bolt 16 can be passed through the through-hole 15, and the production and construction management of the foundation portion is easy.

  In addition, when using the intubation, the error absorption capacity of the misalignment of the pile is completely the same as when not using it, and the amount of filler used is small, the filler is triaxially constrained by the intubation, There are advantages such as increased bearing strength of the filler.

[Second Embodiment]
As shown in the plan view of FIG. 5 and the elevation view of FIG. 6, this second embodiment is provided with a stiffening beam 20 that connects the distal ends of adjacent connecting beams 14 in the first embodiment. The connecting beam 14 and the stiffening beam 20 are rigid joints that join both the flange and the web. A certain amount of stiffening effect can be expected even with web-only joining.

  The pile core often deviates several tens of millimeters from a predetermined position during construction, but when the material core of the connecting beam 14 and the pile core of the steel pile 11 do not match (see FIGS. 5 and 6). Eccentricity E), the product of the axial force N acting on the steel pile 11 through the connecting beam 14 from the column base 4 and the eccentric amount E becomes an eccentric moment M, which acts on the steel pile 11.

  In 1st Embodiment, since the steel pile 11 must resist directly with respect to the combined stress of the axial force N and the eccentric moment M, it is necessary to enlarge the size of the steel pile 11, and it is connected. Since the beam 14 is twisted, it is not preferable.

  In the second embodiment, this problem is solved by providing a stiffening beam 20 that connects the distal ends of the connecting beams 14. That is, since the stiffening beam 20 is rigidly joined to the connecting beam 14, the eccentric moment M is distributed to the two stiffening beams 20 on both sides of the steel pile 11 and is not transmitted to the steel pile 11.

  Thus, in 2nd Embodiment, since eccentric moment M does not act on the steel pile 11 even if eccentricity arises in a pile, high construction precision is not necessarily required. In addition, since it is desirable that the connecting beam 14 configured in a cross shape or the like secures in-plane rigidity, the stiffening beam 20 also has the role.

[Third Embodiment]
As shown in the elevation view of FIG. 7, the third embodiment uses a steel pipe pile 31 having a screw (blade) 30 at the tip of the pile as the steel pile 11 in the first and second embodiments. It is. The screwed steel pipe pile 31 is screwed into the ground while applying rotation, and since there is no residual soil like an embedded pile, it is an environmentally friendly pile and no concrete is required. There is no need for large-scale equipment.

  Therefore, it is advantageous for construction in a confined place, which is often used for construction such as building a building on the platform of a railway station. In addition, the construction period is short and labor is small. Furthermore, since the screw 30 serves as an anchor, it can resist the pulling force of the pile that is likely to occur during an earthquake.

[Fourth Embodiment]
In the fourth embodiment, as shown in the elevation view of FIG. 8, in the first to third embodiments, a horizontal displacement suppression key 40 protrudes downward from the intersection of the connecting beams 14. Since the independent pile foundation according to the present invention has no underground beam, the movement of the column base 4 is more likely to occur during an earthquake than the conventional independent pile foundation with the underground beam. If projecting and adding, the resistance to horizontal movement increases, so the movement of the column base 4 is suppressed, and the seismic safety of the building is improved.

[Fifth Embodiment]
This 5th Embodiment forms the ground improvement body 50 in the circumference | surroundings of the steel pile 11 in the 1st-4th embodiment, as shown to the elevation view of FIG. A soil cement column method that forms a mixture of soil and cement in a columnar shape is suitable as the ground improvement method. That is, the construction is simple, and the generation of residual soil is also consistent with the gist of the present invention.

  Since the ground improvement body 50 formed in the columnar shape plays a role like a thick pile at the time of an earthquake, it exerts a greater horizontal resistance than the case of the steel pile 11 alone, and thus suppresses the movement of the column base 4. Great effect.

[Sixth Embodiment]
As shown in the elevation view of FIG. 10, the sixth embodiment is obtained by adding a vibration suppressing device 60 that suppresses the shaking of the building 5 to the ground structure in the first to fifth embodiments. is there. According to the fifth embodiment, the vibration of the building 5 caused by the earthquake can be attenuated by the vibration suppressing device 60 and the force acting on the foundation can be reduced. The movement can be made difficult to occur.

It is a top view which shows basic 1st Embodiment of the independent pile foundation structure of this invention. FIG. 2 is an elevation view of FIG. 1. FIG. 3 is a partially enlarged sectional view of FIG. 2. FIG. 1 shows an example in which an intubation tube is used in the first embodiment of FIG. 1, where (a) is a plan view, (b) is a vertical sectional view, and (c) is a horizontal sectional view at the bottom of (b). is there. It is a top view which shows 2nd Embodiment which added the stiffening member in the independent pile foundation structure of this invention. FIG. 6 is a partial sectional elevation view of FIG. 5. It is an elevation view which shows 3rd Embodiment using the pile with a screw in the independent pile foundation structure of this invention. It is an elevation view which shows 4th Embodiment which added the horizontal displacement suppression member in the independent pile foundation structure of this invention. It is an elevation view which shows 5th Embodiment which added the ground improvement body to the pile in the independent pile foundation structure of this invention. It is an elevation view which shows 6th Embodiment which added the vibration suppression apparatus to the ground frame in the independent pile foundation structure of this invention. It is a top view which shows an example of the conventional independent pile foundation. FIG. 12 is an elevation view of FIG. 11. It is an elevational view showing a conventional independent pile foundation structure in a narrow area.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pile 2 ... Footing 3 ... Foundation beam 4 ... Column base part 5 ... Above-ground frame (building, shed)
6 ... Pillar 7 ... Site-constructed concrete pile 11 ... Steel pile 11a ... Pile head 12 ... Top plate 13 ... Steel cap 14 ... Connection beam 15 ... Through hole 16 ... Connection bolt 16a ... Lower nut 16b ... Upper nut 17 ... Blocking plate 17a ... Long hole 18 ... Filler 18a ... Filler injection hole 18b ... Air hole 19 ... Intubation 19a ... Bottom plate 20 ... Stiffening beam 30 ... Screw 31 ... Steel pipe pile with screw 40 ... Horizontal displacement suppression key 50 ... Ground Improved body 60 ... Vibration suppression device

Claims (5)

  It is an independent pile foundation structure with a foundation beam made by connecting the pile heads of multiple piles placed with a connection beam, and the connection bolt is inserted on the top end plate provided on the pile head with a gap. The tip of the connecting beam is installed by fastening the top end plate and a closing plate that closes the upper opening of the through hole with a connecting bolt inserted through the through hole. An independent pile foundation structure without foundation beams, wherein a gap around the connecting bolt in the through hole is filled with a filler.   The independent pile foundation structure according to claim 1, wherein a stiffening beam is provided to connect ends of adjacent connecting beams, and the connecting beam and the stiffening beam are joined to each other. Independent pile foundation structure.   The independent pile foundation structure according to any one of claims 1 and 2, wherein a horizontal displacement suppression key is provided on the connecting beam.   The independent pile foundation structure according to any one of claims 1 to 3, wherein the foundation around the pile is improved in ground.   The independent pile foundation structure according to any one of claims 1 to 4, wherein a vibration suppression device is incorporated in the ground frame.

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