JP2016000955A - Pile head pin joining structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile head pin joining structure capable of easily reducing flexural stress caused in a joining part between a foundation pile and an upper structure, without using special material and construction method, while reducing a member cross section of the foundation pile and the upper structure.SOLUTION: A pile head pin joining structure 1 is arranged between a foundation pile 2 buried in an underground part of a building and an upper structure 3, and comprises a composite spring mechanism 6 composed of a shaft material part 4 for exhibiting shear capacity and a coil spring part 5 for reducing axial rigidity, and the shaft material part 4 of the composite spring mechanism 6 is inserted and arranged into a pile head part 7 of the foundation pile 2, and the coil spring part 5 of the composite spring mechanism 6 is inserted and arranged into a space 11 inside of a column of the upper structure 3 via a through-hole 10 of a baseplate 9 provided on the column lower end 8 of the upper structure 3, and the foundation pile 2 and the upper structure 3 are joined.

Description

  The present invention relates to a pile head pin joint structure for joining a pile head of a foundation pile buried in an underground part of a building and an upper structure.

  In conventional buildings, since the foundation pile and the superstructure are joined rigidly, the pile head joint has a structure in which bending stress is transmitted in addition to axial force and shear force. For this reason, in the joint part which a bending stress transmits between a foundation pile and an upper structure, in order to resist the bending stress which acts on a joining boundary part, it was necessary to enlarge a joint part and the surrounding member cross section. However, there is a concern that if the joint between the foundation pile and the superstructure and the cross-section of the surrounding members are enlarged, the amount of materials such as concrete and steel will increase and the construction period will be extended, leading to a rise in construction costs. Yes.

  Against this background, a mechanism has been proposed that reduces the degree of fixation between the pile head of the foundation pile and the upper structure, and reduces the cross-section of the upper structure such as the pile and foundation beam. For example, as a pile head fixing degree reduction mechanism, it has been proposed to relatively reduce the joint rigidity by narrowing the cross section of the joint portion (Patent Document 1).

  In this proposed pile head joint structure, a cross-sectional reduced part is provided at the upper end of the foundation pile, and it is set to have a pile head fixing degree necessary for semi-rigidly joining the foundation pile and the upper structure, A foundation structure provided on the top of the pile is joined to the column. By providing such a structure, the joint portion has a structure close to a pin that transmits an axial force and a shearing force and hardly transmits a bending stress.

  However, in the structure close to the pin like the pile head joint structure described in Patent Document 1, the joint portion with the upper structure and the peripheral member cross section are relatively narrowed down, but in practice, some degree It bears bending stress. For this reason, it cannot be regarded as a pin in the structural design.

  Moreover, the pile head joining structure which hardly produces rotation resistance by attaching a ball seat to a pile head is also proposed (patent document 2).

  In this case, it is comprised by two members, a concave joining member and a convex joining member, and it is comprised as a pile head joining apparatus with which the front-end | tip of a convex joining member is contacting in the concave member inner surface center.

  However, in the method using a ball seat on the pile head as in the pile head joining device described in Patent Document 2, parts with special shapes are required, and the foundation pile and the upper structure are not tightly connected. Therefore, it is pointed out that it is necessary to use in combination with another joining mechanism having a binding function.

Furthermore, a technique has also been proposed in which a curvature is provided at the head of the pile and pin connection is made between the pile and the upper structure without using special parts. (Patent Document 3)
In this proposed foundation pile pin coupling structure, a curvature is provided on the pile head, and a filler capable of following deformation is inserted between the pile structure and the rotation resistance is hardly generated. However, it is pointed out that the construction of the curvature of the pile head part requires on-site accuracy control, which increases the labor of construction. Moreover, since the anchor bolt for binding is inserted between the pile and the upper structure, there is a risk that a certain degree of rotational resistance may occur.

JP 2007-039902 A JP 2003-253688 A JP 2013-112945 A

  The present invention has been made in view of the circumstances as described above. While reducing the cross section of the foundation pile and the upper structure, the foundation pile and the upper structure can be easily used without using special materials and construction methods. It is an object of the present invention to provide a pile head pin joint structure capable of reducing a bending stress generated in a joint portion with an object.

  The pile head pin joint structure of the present invention is a pile head pin joint structure disposed between a foundation pile buried in an underground part of a building and an upper structure, and a shaft member and a shaft that exhibit shear strength. It has a composite spring mechanism consisting of a coil spring part that lowers the rigidity, and the shaft part of the composite spring mechanism is inserted into the pile head of the foundation pile, and the coil spring part of the composite spring mechanism is at the lower end of the column of the superstructure. The foundation pile and the upper structure are joined by being inserted into a space inside the column of the upper structure through a through hole of the provided base plate.

  In the pile head pin joint structure of this invention, it is preferable that a composite spring mechanism is a steel pipe coil spring formed by providing the steel pipe with a helical cut.

  Moreover, in the pile head pin junction structure of this invention, it is preferable that a composite spring mechanism is a thing in which a part of columnar steel material was replaced by the coil spring.

  In the pile head pin joint structure of the present invention, it is preferable that a cushioning material is disposed around the coil spring portion.

  In the pile head pin joint structure of the present invention, it is preferable that a reinforcing member or an inclined member is disposed at a contact portion between the composite spring mechanism and the base plate.

  Moreover, in the pile head pin joining structure of this invention, it is preferable that the inclined surface of an inclined member and the inner edge part of the through-hole of a base board are closely_contact | adhered.

  According to the pile head pin joint structure of the present invention, while reducing the member cross section of the foundation pile and the upper structure, the joint portion between the foundation pile and the upper structure can be easily used without using a special material or construction method. It is possible to provide a pile head pin joint structure capable of reducing the generated bending stress.

It is a schematic sectional drawing of the structure where the pile head pin junction structure of the present invention is applied, and the ready-made pile and the upper structure which does not provide an underground beam are joined. It is a schematic sectional drawing of the structure where the pile head pin junction structure of the present invention is applied and the field construction pile and the upper structure which does not provide an underground beam are joined. It is one form of the compound spring mechanism of the pile head pin joint structure of this invention, and is a schematic sectional drawing at the time of joining a pillar of a foundation pile and a superstructure directly using a steel pipe coil spring. (A) is a schematic sectional drawing which shows the pile head pin junction structure in the normal time. (B) is a schematic sectional drawing which shows the mechanism operation | movement condition of a pile head pin junction structure when the horizontal force by an earthquake etc. is added to the upper structure. It is one form of the composite spring mechanism of the pile head pin joint structure of this invention, and is a schematic cross section which shows the force which acts on a composite spring mechanism at the time of using a steel pipe coil spring for a coil spring part, and the function of each part of a composite spring mechanism FIG. It is one form of the composite spring mechanism of the pile head pin junction structure of this invention, and is a schematic sectional drawing at the time of replacing a part of steel material with a coil spring as a coil spring part. It is one form of the composite spring mechanism of the pile head pin joint structure of this invention, and is a schematic sectional drawing at the time of using the some spring from which a characteristic differs in a coil spring part. It is one form of the composite spring mechanism of the pile head pin joint structure of this invention, and is a schematic sectional drawing at the time of using the spring which turned back and joined to the coil spring part. It is the surface view and AA sectional drawing which showed the shape of the base board of the pillar lower end of the pile head pin junction structure of this invention. It is a schematic sectional drawing at the time of attaching the member for reinforcement to the base board contact part of the pile head pin junction structure of this invention. It is a schematic sectional drawing at the time of attaching the inclined member which makes the motion of a compound spring mechanism smooth to the base board contact part of the pile head pin junction structure of this invention. Schematic sectional view when the composite spring mechanism of the pile head pin joint structure of the present invention is welded and joined to the diaphragm plate attached to the column, and the inclined member that smoothens the movement of the composite spring mechanism is attached to the base plate contact portion It is. It is an enlarged view of the principal part A of FIG. The arrows in the figure indicate the load transmission state in the horizontal direction. It is a schematic sectional drawing at the time of welding and joining to the diaphragm plate attached to the pillar the composite spring mechanism of the pile head pin junction structure of this invention. It is the schematic sectional drawing at the time of attaching the compound spring mechanism of the pile head pin junction structure of the present invention to the H-shaped section pillar, and BB sectional drawing. It is a schematic sectional drawing at the time of reducing the cross-sectional area of the pillar lower end of the pile head pin junction structure of this invention. It is sectional drawing which showed typically the motion at the time of the earthquake of the pile head pin junction structure of this invention in the structure which does not provide an underground beam. (A) is a schematic sectional drawing which shows the state which horizontal force (beta) acted on the right direction of the upper structure, when the upper structure and the foundation pile are joined by the pile head rigid joining of a prior art. (B) is a schematic sectional view showing a state in which a horizontal force β is applied in the right direction of the upper structure when the upper structure and the foundation pile are joined by the pile head pin joint structure of the present invention. .

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

  FIG. 1 is a schematic cross-sectional view of a structure in which a pile head pin joint structure according to the present invention is applied and a ready-made pile and an upper structure not provided with underground beams are joined.

  As illustrated in FIG. 1, a pile head pin joint structure 1 according to the present invention includes a shaft member 4 that exhibits shear strength and is disposed in a foundation pile 2 and an upper structure 3 embedded in an underground part of a building. And a composite spring mechanism 6 comprising a coil spring portion 5 for reducing the shaft rigidity. The shaft member 4 of the composite spring mechanism 6 is inserted into the pile head 7 of the foundation pile 2, and the coil spring portion 5 of the composite spring mechanism 6 is provided on the base plate 9 provided at the column lower end 8 of the upper structure 3. The foundation pile 2 and the upper structure 3 are joined via the column 13 by being inserted into the space 11 inside the column of the upper structure 3 via the through hole 10. The load of the upper structure 3 is transmitted and supported by the foundation pile 2 through such a composite spring mechanism 6.

  The foundation pile 2 is a pile placed vertically in the ground. For example, in addition to ready-made concrete piles such as steel piles, prestressed reinforced concrete piles, steel pipe-covered concrete piles, site-built piles such as cast-in-place concrete piles, etc. Illustrated. In FIG. 1, a steel pipe covered concrete pile is used as the foundation pile 2, and the steel pipe covered concrete pile is filled with the concrete 20 in the hollow portion of the steel pipe 19 and hardened. Moreover, the pile head 7 of the foundation pile 2 has a smooth surface treated with the upper structure 3, and is provided with an opening 12 for arranging the composite spring mechanism 6.

  The pillar 13 of the upper structure 3 is a structure having a smaller cross section than the cross section of the foundation pile 2, and the center of the pillar 13 and the center of the foundation pile 2 are arranged on the same straight line. As a material of the pillar 13, for example, a steel frame such as concrete or H-shaped steel can be used.

  The column 13 includes a space 11 inside the column in which the compound spring mechanism 6 can be inserted because a compound spring mechanism 6 described later is disposed at the column lower end 8. The size and shape of the space 11 inside the column is not limited as long as it is within a range in which the strength of the column 13 is ensured. The space 11 inside the pillar can be filled with concrete, adhesive, or the like in order to insert and fix the composite spring mechanism 6. Such filling of concrete, adhesive, or the like may be performed in advance before the composite spring mechanism 6 is inserted into the space 11 inside the column, or may be performed after the composite spring mechanism 6 is inserted.

  Further, it is preferable that a buffer material 16 is disposed around the coil spring portion 5 of the composite spring mechanism 6. Since the cushioning material 16 is elastically deformed, the movement of the coil spring portion 5 is not hindered, and the space 11 inside the column and the concrete filled in the space 11 inside the column are protected from damage by the elastically deformed coil spring portion 5. It is also possible to do.

  Examples of the material of the buffer material 16 include urethane foam and polystyrene foam.

  The shape of the buffer material 16 is not particularly limited, for example, tubular, columnar, annular, or the like, and the size is not particularly limited as long as the coil spring portion 5 can be covered.

  As shown in FIG. 1, as a fixing method of the composite spring mechanism 6 in the case of using a steel pipe covered concrete pile which is a ready-made concrete pile as the foundation pile 2, for example, an opening 12 is provided at the upper end of the steel pipe covered concrete pile. After the shaft part 4 on the lower end side of the composite spring mechanism 6 is inserted into the opening 12, the upper end of the steel pipe-covered concrete pile is surrounded by a formwork, reinforcing bars are placed and concrete is placed, and the composite spring mechanism 6 protrudes. The method etc. which construct | assemble the pile head 7 to install are illustrated.

  FIG. 2 is a schematic cross-sectional view of a structure in which the pile head pin joint structure of the present invention is applied and a field-constructed pile and an upper structure without an underground beam are joined. Portions common to the embodiment shown in FIG. 1 are denoted by the same reference numerals in the drawing, and description thereof is omitted.

  As shown in FIG. 2, as a method of fixing the composite spring mechanism 6 to the pile head 7 and the upper structure 3 in the case of using a cast-in-place concrete pile as a foundation pile 2, the shaft of the composite spring mechanism 6 is used. Examples thereof include a method in which a base is provided at the end of the material part 4 and fixed to the pile head 7 using a fixing bracket 15 such as an anchor or stud. In addition to this, for example, before the concrete of the site-built pile is hardened, the composite spring mechanism 6 is directly inserted into the pile head 7 and fixed by hardening the concrete, or the adhesive is used in the above method. The method of fixing by this is illustrated.

  In addition, when joining the pile head 7 and the pillar 13 of the upper structure 3, the pile head 7 and the pillar 13 of the upper structure 3 can be joined directly, without providing an underground beam. An underground beam may be provided between the foundation pile 2 and the column 13 of the upper structure 3. In that case, similarly to the pile head 7, the underground beam can be provided with an opening 12 for inserting and arranging the composite spring mechanism 6.

  The composite spring mechanism 6 includes a shaft member 4 that exhibits shear strength and a coil spring portion 5 that reduces shaft rigidity. The composite spring mechanism 6 loads the shearing force from the upper structure 3 to the shaft member 4 having axial rigidity, and loads the pulling load to the joint portion caused by bending to the coil spring part 5 having little shaft rigidity. As a result, a joint structure having a very small rotational resistance while having a shear resistance is realized.

  FIG. 3 is one form of the composite spring mechanism 6 of the pile head pin joint structure 1 of the present invention, and is an outline when the foundation pile 2 and the column 13 of the upper structure 3 are directly joined using the steel pipe coil spring 6a. It is sectional drawing. (A) is a schematic sectional drawing which shows the pile head pin junction structure 1 which is normally formed. (B) is a schematic sectional drawing which shows the mechanism operation | movement condition of the pile head pin junction structure 1 when the horizontal force (beta) by an earthquake etc. is added to the upper structure 3. FIG. FIG. 4 is one form of the composite spring mechanism 6 of the pile head pin joint structure 1 of the present invention, and the force acting on the composite spring mechanism when the steel pipe coil spring 6a is used as the coil spring portion 5a, and the composite spring mechanism 6 is a schematic cross-sectional view showing the function of each part of FIG.

  For example, as shown in FIGS. 3 and 4, the composite spring mechanism 6 is a steel pipe coil spring 6a in which a helical cut is provided in a structural steel pipe, or a part of a columnar steel material as shown in the examples of FIGS. 6b may be replaced by a coil spring.

  In the example of FIG. 3, the steel pipe coil spring 6 a is configured by a coil spring portion 5 a provided with a helical cut in a structural steel pipe and a shaft member portion 4 a provided with no cut. As shown in FIG. 4, the coil spring portion 5a functions as a spring, and even if a large horizontal force β is applied in the event of an earthquake, the coil spring portion 5a can be greatly deformed to greatly reduce the shaft rigidity. it can. Therefore, the coil spring portion 5a bears only the tensile force γ as a load. On the other hand, since the shaft member 4a is not a coil spring, the shaft member 4a can exhibit the inherent shear strength of the shaft member. Therefore, the shaft member 4a bears two forces, a shear force α and a tensile force γ, as loads. Moreover, the shaft member 4a can transmit the horizontal force β to the pile. As described above, the composite spring mechanism 6 is characterized by being provided with two different load-bearing mechanisms although it is a single member.

  Although the steel pipe coil spring 6a is a steel pipe having the same cross section by adjusting the cutting pitch of the coil spring portion 5a and the number of cuts, the shaft rigidity can be arbitrarily adjusted. The cutting interval is preferably about 0.3 to 1.0 times the diameter of the steel pipe, and the number of cuts is preferably about 1 to 4 times.

  Moreover, if the steel pipe coil spring 6a is used, the cutting pitch of the coil spring portion 5a and the number of cuts can be arbitrarily changed. Therefore, the steel pipe coil spring 6a having a plurality of different characteristics using a single steel pipe as a material. Can be produced. Moreover, as shown in FIG. 6, it is also possible to produce the steel pipe coil spring 6a provided with the coil spring part 5b and the coil spring part 5c which each have a several different characteristic in one long steel pipe.

  The term “plurality of characteristics” includes the effective number of turns of the spring, the average coil diameter, the spring constant, and the like.

  As a steel pipe used for the steel pipe coil spring 6a, a general structural steel pipe is exemplified. As described above, the steel pipe coil spring 6a is made of a material used in a general building, so that material procurement and design change are easy, and simple and quick construction is possible.

  In addition, since the coil spring part 5a of the steel pipe coil spring 6a needs to work as a spring, it is preferable to trim the peripheral part so as not to restrain the movement of the spring.

  FIG. 5 is one form of a composite spring mechanism having a pile head pin joint structure according to the present invention, and is a schematic cross-sectional view when a part of the steel material that is the shaft member 4b is replaced with a spring as the coil spring portion 5b. FIG. 6 is an embodiment of a composite spring mechanism having a pile head pin joint structure according to the present invention, and is a schematic cross-sectional view when a plurality of springs having different characteristics are used for the coil spring portions 5b and 5c. FIG. 7 is a schematic cross-sectional view of a composite spring mechanism having a pile head pin joint structure according to the present invention, in which a spring that is folded and joined to the coil spring portion 5d is used.

  As materials used for such columnar steel materials and coil springs, materials used in general buildings are used, and special materials are not necessarily required. Therefore, material procurement, design change and processing are easy, and simple and quick construction is possible.

  Since the composite spring mechanism 6 is manufactured in a factory, it is not necessary to process and adjust a special member at the construction site, leading to labor saving and shortening the construction period at the construction site. Moreover, the composite spring mechanism 6 can prevent the deterioration of the member in advance by performing a rust prevention treatment in advance. Furthermore, since the composite spring mechanism 6 does not require special management during building operation, a maintenance-free structure can be provided. Therefore, it is not necessary to provide equipment necessary for checking the pile head 7.

  In addition, the composite spring mechanism 6 shall not carry out a shear yield. Further, the composite spring mechanism 6 may be axially yielded.

  FIG. 8: is the surface view and AA sectional drawing which showed the shape of the base board of the pillar lower end of the pile head pin junction structure of this invention. The base plate 9 is a metal plate having a substantially square shape as shown in FIG. 8, and a through hole 10 through which a composite spring mechanism can be inserted is opened at the center thereof. The end portion of the base plate 9 and the inner edge portion 10a of the through hole 10 may be chamfered or may form a reverse tapered surface in order to realize smooth deformation of the composite spring mechanism.

  The hole diameter of the through-hole 10 is set to be large enough to be allowed in normal construction with respect to the diameter of the shaft member. As a normal construction error, for example, the diameter of the shaft member plus about 5 mm is preferable. By inserting the composite spring mechanism 6 into the through hole 10 of the base plate 9 having a diameter larger than the diameter of the shaft member, there is a backlash between the base plate 9 and the composite spring mechanism 6. The structure does not constrain the assumed level of rotational deformation. And since there is a clearance of a normal construction level between the shaft member 4 and the upper structure 3 for transmitting the shearing force, it is possible to transmit all the pulling force to the coil spring portion by the joint deformation. is there.

  The base plate 9 also serves as a stopper for preventing the coil spring portion 5 of the composite spring mechanism 6 from falling off the space 11 inside the column.

  The material used for the base plate 9 is a metal material used in general buildings, and does not necessarily require a special material. Therefore, material procurement, design change and processing are easy, and simple and quick construction is possible. In addition, the base plate 9 can be prevented from being deteriorated by carrying out a rust prevention treatment in advance.

  FIG. 9 is a schematic cross-sectional view when a reinforcing member is attached to the base plate contact portion of the pile head pin joint structure of the present invention. FIG. 10 is a schematic cross-sectional view when an inclined member that smoothens the movement of the composite spring mechanism is attached to the base plate contact portion of the pile head pin joint structure of the present invention.

  It is preferable that a reinforcing member 17 is disposed at the contact portion between the base plate 9 and the composite spring mechanism 6 as shown in FIG. The reinforcing member 17 is disposed for the purpose of protecting the contact portion between the base plate 9 and the composite spring mechanism 6, and the shape thereof is preferably annular. By arranging such a reinforcing member 17, the bearing strength in the shaft member 4 can be improved.

  Further, it is preferable that an inclined member 18 is disposed at the contact portion between the base plate 9 and the composite spring mechanism 6 as shown in FIG. The inclined member 18 is disposed for the purpose of causing the contact portion between the base plate 9 and the composite spring mechanism 6 to behave smoothly, and the shape thereof is preferably an annular member having a tapered surface formed in part.

  Furthermore, as shown in FIG. 11, it is preferable that the inclined surface 18 a of the inclined member 18 and the inner edge portion 10 a of the through hole 10 of the base plate 9 are in close contact with each other. That is, when the inclined surface 18a of the inclined member 18 and the inner edge portion 10a of the through hole 10 of the base plate 9 are in close contact, the load transmitted from the base plate 9 to the inclined member 18 is inclined as shown in FIG. The member 18 has a component force parallel to the inclined surface 18a. The component force in the direction parallel to the inclined surface 18 a of the inclined member 18 cancels the frictional force generated between the inclined surface 18 a of the inclined member 18 that is in contact with the inner edge portion 10 a of the through hole 10 of the base plate 9. For this reason, as indicated by the arrows in the figure, a force in the direction of lifting the base plate 9 is generated, the movement of the base plate 9 is smoothed, and the inclined surface 18a of the inclined member 18 and the base plate 9 are penetrated. By reducing the rotational resistance of the contact surface with the inner edge 10a of the hole 10, the degree of fixation of the contact surface can be reduced. In this case, a reverse tapered surface needs to be formed on the inner edge portion 10 a of the through hole 10 of the base plate 9.

  In FIG. 12, the inclined surface 18 a of the inclined member 18 extends below the lower surface of the base plate 9, but the inclined surface 18 a does not necessarily have to extend below the lower surface of the base plate 9. Alternatively, a form in which the lower surface of the base plate 9 and the lower end of the inclined surface 18a are in contact with each other is also considered.

  The curvature of the inclined member 18 and the inclination angle of the inclined surface 18a are not particularly limited as long as the desired performance is exhibited, but the inclination angle is preferably about 1/3 to 1/4.

  The material used for the reinforcing member 17 and the inclined member 18 is a metal material used in a general building, and does not necessarily require a special material. Therefore, material procurement, design change and processing are easy, and simple and quick construction is possible. The reinforcing member 17 and the inclined member 18 can be prevented from being deteriorated by applying a rust prevention treatment in advance.

  Next, the arrangement | positioning method of the composite spring mechanism 6 in the pile head pin junction structure 1 of this invention is demonstrated in detail.

  First, the foundation pile 2 is constructed in the ground by reaching the support layer in the same manner as the conventional foundation pile construction method. An opening 12 is formed in the pile head 7 of the foundation pile 2, and the shaft member 4 of the composite spring mechanism 6 is inserted into the opening 12 and fixed. The shaft portion 4 of the composite spring mechanism 6 may be constructed with concrete after being inserted into the hollow portion of a ready-made concrete pile, or inserted directly into the pile head 7 before the concrete of the field-built pile is hardened. Later, it may be fixed with concrete.

  The mounting position of the composite spring mechanism 6 is ideally a pile core, but may be a position shifted from the pile core due to the influence of construction errors and other storage.

  Next, the coil spring portion 5 of the composite spring mechanism 6 is inserted into the through hole 10 opened in the base plate 9. In the embodiment shown in FIGS. 1 to 3, the contact on the side of the composite spring mechanism 6 to which the shearing force is transmitted in contact with the base plate 9 is the shaft member portion 4, and is not a coil spring. It is necessary to maintain the original shape of the material. Further, in the embodiment shown in FIGS. 9 to 11, the shaft member 4 and the base plate 9 of the composite spring mechanism 6 are not in direct contact, and the shaft member 4 is sheared via the reinforcing member 17 and the inclined member 18. Power is transmitted.

  By inserting the composite spring mechanism 6 into the through hole 10 of the base plate 9, the foundation pile 2 and the column 13 of the upper structure 3 are tightly coupled. When the composite spring mechanism 6 is inserted into the through hole 10 of the base plate 9, it is preferable to apply a tensile load to the composite spring mechanism 6 and insert it under tension. By applying a tensile load, the inner edge portion 10a of the through hole 10 of the base plate 9 and the inclined surface 18a of the inclined member 18 are always in contact with each other. It is possible to prevent a gap from being generated. The base plate 9 is attached to the column lower end 8 by welding.

  As a method of fixing the composite spring mechanism 6 to the pile head 7 and the upper structure 3, the composite spring mechanism 6 is provided in the opening 12 provided in the pile head 7 and the space 11 inside the column of the upper structure 3 as described above. In addition to the method of embedding, for example, a method of fixing with concrete or an adhesive, a method of providing a base at the end of the steel pipe and fixing using a fixing bracket 15 such as an anchor or a stud, etc. are exemplified.

  As shown in FIGS. 11 and 13, when the column 13 of the superstructure 3 is a steel column, the shaft member 4 on the upper side of the composite spring mechanism 6 is welded and joined in advance to the diaphragm plate 22. The composite spring mechanism 6 may be fixed by welding the plate 22 and the column 13 of the upper structure 3 by welding. In this case, since the concrete 20 is not required for fixing the composite spring mechanism 6 and the column 13 of the upper structure 3, the space 11 inside the column remains hollow in the column lower portion 23 welded to the diaphragm plate 22. It is. The composite spring mechanism 6 and the column 13 of the superstructure 3 can be fixed by welding and joining in the same manner as normal steel work. Therefore, the composite spring mechanism 6 is simply fixed without requiring any special technique. It is possible.

  Further, as shown in FIG. 14, when the column 13 of the superstructure 3 is an H-shaped column 24, the shaft member 4 on the upper side of the composite spring mechanism 6 is welded and joined in advance to the diaphragm plate 22. The composite spring mechanism 6 may be fixed by welding the plate 22 and the column 13 of the upper structure 3 by welding. In this case, a notch 26 is provided in at least a part of the web 25 of the H-shaped cross-sectional column 24 in the column lower portion 23 welded to the diaphragm plate 22, and a space in which the coil spring portion 5 of the composite spring mechanism 6 can be deformed is provided. It is necessary to secure. In addition, since the concrete 20 is not required for fixing the composite spring mechanism 6 and the column 13 of the superstructure 3, the space inside the column welded to the diaphragm plate 22 remains hollow. The composite spring mechanism 6 and the column 13 of the superstructure 3 can be fixed by welding and joining in the same manner as normal steel work. Therefore, the composite spring mechanism 6 is simply fixed without requiring any special technique. It is possible.

  The composite spring mechanism 6 has low rigidity and does not receive a large load in the range of deformation that occurs in the joint. Therefore, fixing by a simple method such as concrete embedding as shown in FIGS. On the other hand, when the column lower ends 8 are collectively manufactured for factory production, the composite spring mechanism 6 is welded to a diaphragm plate 22 as shown in FIGS. In this case, no special technique is required because the welding method may be the same as that of ordinary steel construction.

  Further, as shown in FIG. 15, when the ground contact area of the column lower end 8 is reduced, the geometrical rotational resistance generated when the column 15 of the upper structure 3 receives an axial force is further reduced. Is also possible.

  As described above, the pile head pin joint structure 1 of the present invention can bind the foundation pile 2 and the upper structure 3 by a simple method by using the composite spring mechanism 6. By disposing such a composite spring mechanism 6 between the foundation pile 2 and the upper structure 3, the composite spring mechanism 6 can be subjected to a pulling load due to bending stress applied to the upper structure 3 during an earthquake or the like. The shearing force can be transmitted from the upper structure 3 to the foundation pile 2. Moreover, since the composite spring mechanism 6 follows deformation, the shaft rigidity is reduced, and the bending stress is not transmitted to the pile head 7.

  The allowable deformation capacity of the composite spring mechanism 6 is determined by the clearance of the through hole 10 of the base plate 9 provided in the shaft member 4 of the composite spring mechanism 6 and the column lower end 8 of the upper structure 3. Even with management level errors, 1/10 rad or more can be secured.

  Moreover, you may provide the some composite spring mechanism 6 with respect to the pillar 13 of the one foundation pile 2 and the upper structure 3 as needed. By disposing a plurality of composite spring mechanisms 6, the degree of freedom in design is increased as compared with the case where there is only one composite spring mechanism 6, and damage to the pile head 7 can be suppressed. When a plurality of compound spring mechanisms 6 are provided, the compound spring mechanisms 6 are preferably provided at positions that are line-symmetric or point-symmetric in plan view with the pile core as the center.

  Next, operation | movement of the pile head pin junction structure 1 of this invention is demonstrated in detail.

  FIG. 16: is sectional drawing which showed typically the motion at the time of the earthquake of the pile head pin junction structure 1 of this invention in the structure which does not provide an underground beam. FIG. 16A is a schematic cross-sectional view showing a state in which a horizontal force β acts on the right side of a building when the upper structure 3 and the foundation pile 2 are joined by a conventional pile head rigid joint. is there. FIG. 16B shows a state in which a horizontal force β is applied in the right direction of the upper structure when the upper structure 3 and the foundation pile 2 are joined by the pile head pin joint structure 1 of the present invention. It is a schematic sectional drawing.

  FIG. 16A shows a state in which a horizontal force β acts on the upper structure 3 from the left to the right due to the occurrence of an earthquake, but the foundation pile 2 and the column 13 of the upper structure 3 are rigidly joined. Therefore, pile head bending stress is concentrated at the joint, and there is concern about damage to the pile head 7 of the foundation pile 2. When the left ground is relatively hard, as shown in FIG. 16A, the column shear force α1 and the pile head bending stress δ1 applied to the left column 13 are large, and the column shear force applied to the right column 13 is large. α2 and pile head bending stress δ2 become small, and damage to the pillars 13 of the foundation pile 2 and the upper structure 3 may be concentrated on the left side.

  On the other hand, FIG. 16B shows a state in which a horizontal force β is applied from the left direction to the right direction due to the occurrence of an earthquake on a building to which the pile head pin joint structure 1 of the present invention is applied. When the coil spring part 6 follows the deformation, bending stress is hardly applied to the foundation pile 2 and the column 13 of the upper structure 3. And as shown in FIG.3 (b), when the coil spring part 5 is extended, the upper structure 3 floats up easily from the pile head 7 of the foundation pile 2, and column shear force (alpha) and bending stress (delta) are almost all. Since it does not act, the junction part of foundation pile 2 and upper structure 3 is not damaged.

  Thus, the pile head pin joint structure 1 of the present invention is arranged at the joint portion between the foundation pile 2 and the upper structure 3 by disposing the composite spring mechanism 6 at the joint portion between the foundation pile 2 and the upper structure 3. The bending stress that occurs can be reduced as much as possible, and the cross-sectional areas of the pillars 13 of the foundation pile 2 and the superstructure 3 can be rationally reduced in a form that ensures safety compared to the pile head rigid joint. Is possible.

  Moreover, since the transmission of the bending stress between the underground part below the foundation pile 2 and the upper structure 3 is eliminated by using the pile head pin joint structure 1 of the present invention, for example, without providing an underground beam Even in a building or the like in which the foundation pile 2 and the column 13 of the upper structure 3 are directly joined, it is possible to minimize the increase in the member cross section and further simplify the structural design model.

  And since the pile head pin joining structure 1 of this invention has the characteristic close | similar to the model on a structural design compared with the conventional pin joining structure, it makes it possible to implement | achieve a building with little separation from a structural design model. As described above, the pile head pin joint structure 1 according to the present invention can realize a building with less burden on the building and the foundation as in the structural design model. Therefore, the low cost building can be shortened while maintaining necessary structural performance. It can be realized in the construction period.

DESCRIPTION OF SYMBOLS 1 Pile head pin joint structure 2 Foundation pile 3 Superstructure 4, 4a, 4b Shaft part 5, 5a, 5b, 5c, 5d Coil spring part 6 Compound spring mechanism 6a Steel pipe coil spring 6b A part of columnar steel material is a coil spring 7 Pile head 8 Column lower end 9 Base plate 10 Through hole 10a Inner edge 11 Column interior space 12 Opening 13 Column 14 Foundation 15 Fixing bracket 16 Buffering material 17 Reinforcement annular member 18 Inclined member 18a Inclined Surface 19 Steel pipe 20 Concrete 21 Ground surface 22 Diaphragm plate 23 Column bottom 24 H-shaped column 25 Web 26 Web notch

Claims (6)

It is a pile head pin joint structure arranged between the foundation pile buried in the underground part of the building and the upper structure,
Provided with a composite spring mechanism consisting of a shaft material portion that exhibits shear strength and a coil spring portion that reduces shaft rigidity,
The shaft member portion of the composite spring mechanism is inserted and arranged in the pile head of the foundation pile, and the coil spring portion of the composite spring mechanism is connected to the upper structure through the through hole of the base plate provided at the lower end of the column of the upper structure A pile head pin joint structure, wherein the foundation pile and the upper structure are joined by being inserted and arranged in the space inside the pillar.   The pile head pin joint structure according to claim 1, wherein the composite spring mechanism is a steel pipe coil spring in which a spiral cut is provided in a steel pipe.   2. The pile head pin joint structure according to claim 1, wherein the composite spring mechanism is obtained by replacing a part of a columnar steel material with a coil spring.   The pile head pin joint structure according to any one of claims 1 to 3, wherein a buffer material is disposed around the coil spring portion.   The pile head pin joint structure according to any one of claims 1 to 4, wherein a reinforcing member or an inclined member is disposed at a contact portion between the composite spring mechanism and the base plate.   The pile head pin joint structure according to any one of claims 1 to 5, wherein an inclined surface of the inclined member and an inner edge portion of the through hole of the base plate are in close contact with each other.

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