JP3690395B2 - Joint structure of support pile and structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention belongs to the technical field of the joint structure between the pile head of the support pile and the structure, and more specifically, the pile head of the support pile and the structure are provided with a suitable gap between them, It is related with the connection structure of a support pile and a structure which can reduce effectively the bending moment which arises in the junction part of the said pile head and a structure by connecting with the steel frame member which comprises a plastic hinge .
[0002]
[Prior art]
Horizontal forces act on structures such as support piles and buildings due to earthquakes and winds. Usually, the pile head of the support pile and the foundation beam or mat slab and footing of the structure are tightly coupled by a reinforcing bar or the like and are rigidly joined. As a result, a bending moment is generated at the joint between the pile head and the structure as the horizontal force acts.
[0003]
As a technique for reducing the bending moment generated in the joint,
(1) A structure in which a pile head of a support pile and a foundation beam portion of a structure are joined via a column member having a smaller bending rigidity than the pile head with a gap provided therebetween. Thus, the bending moment generated in the joint portion has been reduced (see, for example, Patent Documents 1 to 3). As the column member having bending rigidity smaller than that of the pile head, an iron lump, a concrete filled steel pipe (CFT), a reinforced concrete (RC) column, a steel reinforced concrete (SRC) column, or an H-shaped steel column is used. It was.
[0004]
(2) The steel pipe pile and the footing are joined via a joint steel pipe with a gap between them, and the joint is filled with a ground having higher rigidity than the conventional ground. The bending moment generated in the above is reduced (see, for example, Patent Documents 4 to 6).
[0005]
[Patent Document 1]
JP 2000-104336 A [Patent Document 2]
JP 2000-144904 A [Patent Document 3]
JP 2000-282484 A [Patent Document 4]
JP 2001-159142 A [Patent Document 5]
Japanese Patent Laid-Open No. 2002-4298 [Patent Document 6]
JP 2002-54158 A [0006]
[Problems to be solved by the present invention]
About the said prior art (1), if the said column member implements it as a cross section which can fully bear the shear force and axial force which act on a pile head, the cross section of a column will become large. Along with this, the bending strength of the column members increases, so in order to reduce the bending moment of the pile head, the gap between the pile head and the structure must be made very large. Stable and harmful deformation tends to remain, which is not practical. On the other hand, when the cross section of the column member is made small, there is a problem that it cannot withstand axial force (compressive stress and tensile stress) and shear force.
[0007]
Regarding the above prior art (2), there is no contrivance in the joining structure itself of the steel pipe pile and the footing, and the technique for reducing the bending moment generated in the joint is secondary, and labor and cost are reduced. It was bulky and there was room for improvement.
[0008]
An object of the present invention, a pile head and the structure of the support piles, provided suitable clearance between them, by coupling with steel members constituting the plastic hinge, effectively reduce the bending moment It is possible to provide a joint structure between a support pile and a structure.
[0009]
[Means for Solving the Problems]
As a means for solving the above-described problem, the joint structure between the support pile and the structure according to the invention described in claim 1 is:
A steel member provided on pile head of the support piles, are matched and the steel member provided at the lower portion of the structure is provided with a gap between the pile head and the structure was combined can butt It said upper and lower steel member, characterized in that塑 property hinge is configured with respect to a bending moment is coupled to lead a straight direction of tensile stress Therefore the energy absorbing member plastically deformed.
[0010]
The joint structure between the support pile and the structure according to the invention described in claim 2 is:
At the end of one of the steel member provided at the pile head of the support pile and the steel member provided at the lower end of the structure, the tie band is fixed in an arrangement surrounding the steel member. The end of the other steel member is inserted into the inside of the tie band, the upper and lower steel members are butted, and a gap is provided between the pile head and the structure. The steel member is characterized in that the tie band and the other steel member are connected by an energy absorbing member that is plastically deformed by a tensile stress in the vertical direction to form a plastic hinge against a bending moment .
[0011]
According to a third aspect of the present invention, in the joining structure of the support pile and the structure according to the first or second aspect , an axial convex portion is provided at an end of one of the upper and lower steel members. The other steel frame member is provided with an axial recess, and the ends of the upper and lower steel members are abutted with each other by fitting the projection and the recess .
[0012]
Embodiments and Examples of the Invention
FIG. 1 shows an embodiment of a joint structure between a support pile 1 and a structure 2 described in claim 1.
[0013]
Provided by inserting the required length into the pile head 1a of the support pile 1 and inserting the required length into the steel member 3b having a smaller diameter than the pile head 1a and the lower end of the structure 2. The steel frame member 3 a is abutted in series, and a gap H is provided between the pile head 1 a and the structure 2. The butted upper and lower steel member 3a, 3b is (the invention according to claim 1) in which the vertical direction of the tensile stress thus coupled with the energy absorbing member 4 to plastically deform bending塑 of the hinge for the moment is constituted .
[0014]
The support pile 1 may be a so-called support pile 1 such as a steel pipe pile or a reinforced concrete pile, and the type of the pile is not particularly limited.
[0015]
Although the structure 2 specifically shows the foundation beam 2 of the structure, the structure 2 is not limited to this, and the structure 2 can be implemented in substantially the same manner with a mat slab or footing.
[0016]
The upper and lower steel members 3a and 3b are implemented by rectangular steel pipe columns having the same shape and the same size in cross section, and the upper end of the upper steel member 3a is formed at the lower end of the structure 2, such as concrete. It is firmly fixed by the fixing means, and the lower end portion of the lower steel frame member 3b is also firmly fixed to the pile head 1a by fixing means such as concrete. The steel members 3a and 3b are not limited to square steel pipe columns, and can be implemented in substantially the same manner with circular steel pipe columns or H-shaped steel columns as shown in FIGS. 4A and 4B.
[0017]
As shown in FIG. 2, the lower end surface 3c of the upper steel member 3a is connected to a contact state (metal touch) that can be lifted to the upper end surface 3c of the lower steel member 3b, and the compressive stress is the steel member 3a, The tensile stress is transmitted between the column cross-sections 3c and 3c of 3b, and the energy of the tensile stress can be absorbed by the steel plate 4 used as the energy absorbing member 4 and the lifting effect of the upper steel member 3a . The horizontal force (shearing force) is resisted by the strength and rigidity of the steel plate 4 used as the energy absorbing member 4.
[0018]
In the illustrated example, the upper and lower steel members 3a and 3b are protruded by substantially the same length and are in contact with each other at substantially the center of the gap H, but the contact position is not limited to this. , it may be carried out in contact with structure above the gap between the H moiety may be carried out in contact with structure in the lower.
[0019]
As shown in FIG. 3, the steel plate 4 used as the energy absorbing member 4 is arranged in a total of four pieces of steel members (square steel pipe columns) 3a and 3b, one on each side, and the upper end portion (upper half) of the steel plate 4 is arranged. One side is brought into contact with the lower end of the upper steel member 3a and directly joined by a welding means such as welding, and one side of the lower end (lower half) is brought into contact with the upper end of the lower steel member 3b and welded. It is directly joined by joining means such as.
[0020]
In the present embodiment, the steel plate 4 made of ordinary steel is used as the energy absorbing member 4. However, the present invention is not limited to this, and a hysteresis damper such as an extremely low yield point steel or a low yield point steel is used. But of course it can be done. When there is a concern about the increase in yield stress due to welding when using the ultra-low yield point steel, the region not affected by welding heat is set as the deformation length, and the length does not deteriorate performance due to buckling. Remember to design.
[0021]
The shape, arrangement, and number of sheets used of the steel plate 4 are not limited to the illustrated example. It can be flexibly changed according to the shape of the steel members 3a and 3b, etc., on the condition that a strength capable of bearing a shearing force necessary for the structural design can be obtained. For example, when the steel members 3a and 3b are circular steel pipe columns, as shown in FIG. 4A, the required number of steel plates 4 having a curvature that exactly overlaps the outer periphery of the circular steel pipe columns 3a and 3b (four in the illustrated example). ) Use and join directly by welding means. When the steel members 3a and 3b are H-shaped steel columns, as shown in FIG. 4B, a total of four steel plates 4 are provided on the outer surface of the flange portion of the H-shaped steel column and both side surfaces of the web portion. It is carried out by directly joining with a joining means such as welding.
[0022]
Accordingly, the horizontal force (shearing force) at the time of the earthquake is resisted by the strength and rigidity of the steel plate 4 used as the energy absorbing member 4, and the connection state of the upper and lower steel members 3a and 3b is stably maintained. Further, when tensile stress is applied, seismic energy is absorbed and excessive deformation is suppressed by the floating of the upper steel member 3a and the plastic deformation of the steel plate 4 used as the energy absorbing member 4 associated therewith. . Therefore, there is no possibility of generating shocking noise when the upper steel member 3a is restored. Further, when receiving a bending moment at the joint between the pile head 1a and the structure 2, the steel plate 4 used as the energy absorbing member 4 at the contact portion of the upper and lower steel members 3a, 3b has a plastic hinge against the bending moment. Since it comprises, the bending moment which arises in the said junction part can be reduced, and by extension, the seismic response which acts on structures 2 such as a building can be reduced.
[0023]
5 and 6 show stepwise embodiments of the joint structure of the support pile 1 and the structure 2 according to the invention described in claim 2 . Compared with the above-described embodiments according to FIGS. 1 to 4, this embodiment is for improving the shear strength when it is difficult to bear the shear force due to the structural design only with the energy absorbing member 4. It is preferably implemented.
[0024]
FIGS. 5A to 5C show that a tie band 5 having strength and rigidity that can withstand shearing force acting on the joining portion is attached to the upper end portion of the lower steel member 3b among the steel members 3a and 3b joined up and down. The state which provided in cyclic | annular arrangement | positioning surrounding the outer periphery of this is shown. Incidentally, FIG. 5A shows a square steel pipe column, FIG. 5B shows a circular steel pipe column, and FIG. 5C shows an H-shaped steel column. Each of the tie bands 5 is also made of steel, and is fixed to the lower steel frame member 3b by joining means such as welding.
[0025]
The lower end portion of the upper steel member 3a is inserted into the inside of the tie band 5 and connected to a contact state (metal touch) that can be lifted to the upper end surface of the lower steel member 3b (reference numeral 3c is the corresponding one). Tangent position).
[0026]
In this embodiment, the tie band 5 is provided at the upper end of the lower steel member 3b . However, as shown in FIG. 6C, the tie band 5 is substantially provided at the lower end of the upper steel member 3a. Ru can be carried out in the same manner.
[0027]
FIG 6A~C the upper and lower steel member 3a connected to the contact state as described above, for 3b, the energy absorbing member and the steel member 3a of the tie band 5 and the upper is thus plastically deformed in the vertical direction of the tensile stress 4 shows the connected state (the invention according to claim 2). Incidentally, all the steel members 3a and 3b used in FIGS. 6A to 6C show a case where the steel members are implemented by square steel pipe columns.
[0028]
Specifically, FIG. 6A, upper and lower steel member 3a, substantially centrally shows the contact state, the lower steel member the tie band 5 only projecting the gap H moiety substantially the same length 3b respectively provided at the upper end portion of 3b, using four steel plates 4 to be used as an energy absorbing member 4, the upper end portion 4a is joined by welding to the upper steel member 3a, the lower portion 4b the upper end surface of the tie band 5 It is joined by welding.
[0029]
FIG. 6B shows a state in which the upper steel member 3a is long and the lower steel member 3b is protruded short and is in contact with the lower portion of the gap H. Similarly to FIG. 6A, the tie band 5 is provided at the upper end portion of the steel frame member 3b, using four steel plates 4 to be used as an energy absorbing member 4, the upper end portion 4a is joined by welding to the upper steel member 3a, the lower unit 4b of the tie band 5 It is joined to the upper end surface by welding.
[0030]
FIG. 6C shows a state in which the upper steel member 3a is shortened and the lower steel member 3b is protruded long and is in contact with the upper portion of the gap H, and the tie band 5 is connected to the lower end of the upper steel member 3a. in the provided, using four steel plates 4 to be used as an energy absorbing member 4, the upper end portion 4a is joined by welding to the lower end surface of the tie band 5, the lower portion 4b is welded to the lower steel member 3 b It is joined .
[0031]
In the present embodiment, the thickness of the steel plate 4 and the thickness of the tie band 5 are substantially the same and the outer peripheral surface is flush with each other. However, the present invention is not limited to this.
[0032]
Therefore, according to the embodiment of the joint structure between the support pile and the structure according to the invention described in claim 2, in addition to the same function and effect as the embodiment according to FIGS. In addition to the strength and rigidity of the steel plate 4 used as the energy absorbing member 4 , the horizontal force (shearing force) can be resisted by the strength and rigidity of the tie band 5, so that the upper and lower steel members 3 a and 3 b The connection state can be maintained more stably.
[0033]
7A to 7C show an embodiment of a joint structure between the support pile 1 and the structure 2 according to the invention described in claim 3 . Similar to the embodiment according to claim 2 described above, this embodiment bears a shearing force in terms of structural design only with the steel plate 4 as compared with the embodiment according to FIGS. This is preferably performed to improve the shear strength in difficult cases.
[0034]
Compared with the embodiments according to FIGS. 1 to 4 described above, the present embodiment has an axially downward projecting portion 6a at the lower end portion of the upper steel member 3a among the steel members 3a and 3b joined up and down. The difference is only that the lower steel frame member 3b is provided with a recess 6b that opens upward in the axial direction at the upper end of the lower steel member 3b. However, in FIG. 7C, the edge part itself of the H-shaped steel column 3 is implemented as the recess 6b.
[0035]
In addition, the shape of the said convex part 6a and the recessed part 6b is not limited to the example of illustration, What is necessary is just the shape where the fitted convex part 6a and the recessed part 6b exhibit what is called a dowel effect. Of course, the same can be implemented by providing the convex portion 6a in the lower steel member 3b and providing the concave portion 6b in the upper steel member 3a.
[0036]
Therefore, according to the embodiment of the joint structure between the support pile and the structure according to the invention described in claim 3 , in addition to the same operational effects as the embodiment according to FIGS. In addition to the strength and rigidity of the steel plate 4 used as the energy absorbing member 4 , the so-called dowel effect (bearing effect) between the fitted convex portions 6 a and the concave portions 6 b is also applied to the horizontal force (shearing force). since the resistance can be retained steel members 3a of the upper bottom, the connection state of 3b further stably.
[0037]
Although the embodiments have been described with reference to the drawings, the present invention is not limited to the embodiments shown in the drawings, and is within the scope of design changes and application variations that are usually made by those skilled in the art without departing from the technical idea thereof. In order to include that.
[0038]
For example, by combining the technical idea of using the tie band described with reference to FIGS. 5 and 6 and the technical idea of exhibiting the dowel effect described with reference to FIG. The state can be maintained remarkably and stably, and a structure having sufficient shear strength can also be implemented (the invention according to claim 3 ).
[0039]
[Effects of the present invention]
According to the joint structure between the support pile and the structure according to the invention described in claim 1,
1) The horizontal force (shearing force) during an earthquake is resisted by the strength and rigidity of the energy absorbing member, and the connection state of the upper and lower steel members is stably maintained. When tensile stress is applied, seismic energy is absorbed and excessive deformation is suppressed by the floating of the upper steel member and the accompanying plastic deformation of the energy absorbing member. Therefore, there is no possibility of generating shocking noise when the upper steel member is restored.
2) When the steel member is subjected to a bending moment, the energy absorbing member at the contact portion of the upper and lower steel members constitutes a plastic hinge, so the bending moment generated at the joint (pile head) can be reduced, and as a result The seismic response acting on the structure can be reduced.
3) The gap between the pile head and the structure is sufficient to allow the steel member to accept the plastic hinge, so there is no need to make it very large as in the prior art, and there is no harmful deformation to the structure. It will not remain.
4) According to the joint structure between the support pile and the structure according to the invention described in claims 2 and 3 , in addition to the effects of 1) to 3), the connection state of the upper and lower steel members is further stabilized. The structure which can hold | maintain and has sufficient shear strength can be implement | achieved.
[Brief description of the drawings]
FIG. 1 is an elevational view showing an embodiment of a joint structure between a support pile and a structure portion according to the invention described in claim 1;
FIG. 2 is an exploded perspective view showing a square steel pipe column used in FIG.
3 is a cross-sectional view showing the main part of FIG. 1. FIG.
FIG. 4A shows a cross-sectional view when the steel member is implemented with a circular steel pipe column, and FIG. 4B shows a cross-sectional view when the steel member is implemented with an H-shaped steel column.
5A, 5B, and 5C, the tie band according to the invention described in claim 2 is provided so as to surround the lower steel member, and the end of the upper steel member is the end of the tie band. It is the perspective view which showed the step inserted inside .
FIGS. 6A and 6B are elevation views showing an embodiment of a joint structure between a support pile and a structure portion according to the invention described in claim 2 ; FIGS.
FIGS. 7A and 7B are exploded perspective views each showing an embodiment of a joint structure between a support pile and a structure portion according to the third aspect of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Support pile 1a Pile head 2 Structure 3a Upper steel member 3b Lower steel member 4 Energy absorption member (steel plate)
5 Tie band 6a Convex part 6b Concave part

Claims (3)

A steel member provided on pile head of the support piles, are matched and the steel member provided at the lower portion of the structure is provided with a gap between the pile head and the structure was combined can butt It said upper and lower steel member, characterized in that塑 property hinge is configured with respect to a bending moment is coupled to lead a straight direction of tensile stress Therefore the energy absorbing member plastically deforms, the junction between the support piles and the structure structure . At the end of one of the steel member provided at the pile head of the support pile and the steel member provided at the lower end of the structure, the tie band is fixed in an arrangement surrounding the steel member. The end of the other steel member is inserted into the inside of the tie band, the upper and lower steel members are butted, and a gap is provided between the pile head and the structure. A steel pile member is characterized in that the tie band and the other steel piece member are connected by an energy absorbing member that is plastically deformed by a tensile stress in the vertical direction to form a plastic hinge against a bending moment. Bonding structure with objects. An axial convex portion is provided at the end of one of the upper and lower steel members, and an axial concave portion is provided at the end of the other steel member. The convex portion and the concave portion are fitted to each other. junction structure between the characterized in that the ends of the upper and lower steel member is butted, bearing pile and the structure according to claim 1 or 2 combined.

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