JP4828450B2 - Pile design method - Google Patents

Description

  The present invention relates to a pile design method used when designing a pile head joint capable of reducing a bending moment generated in a pile head.

  There are two types of pile foundations: a support pile type and a friction pile type. When the good quality support layer is deep underground, the former is constructed by constructing an upper structure on the pile driven to the support layer. This is a form in which the weight is stably supported by the support layer, and the latter is a basic form in which the superstructure is supported by the frictional force with the surrounding ground when there is no good quality support layer.

  These piles are joined to the foundation slab or foundation beam of the superstructure at the head of the pile. At such joints, a compressive force acts as a long-term load. Pull-out force due to, shear force or bending moment due to horizontal force acts.

  When the superstructure encounters an extremely large earthquake, an excessive shearing force or bending moment acts on the pile head, which may lead to an unexpected situation such as destruction of the pile and eventually collapse of the superstructure.

  Therefore, recently, in order to reduce the bending moment generated at the pile head, a part of the deformed stud standing on the end plate of the pile head is cut or a part of the pile head rebar is a cylinder (sheath tube). , Sleeve) or by applying asphalt to the anchor bolts to weaken or cut the adhesion between the concrete constituting the foundation slab and deformed studs, pile head reinforcement or anchor bolts. Processing has come to be performed.

  By performing such an unbonding process, it is possible to reduce the bending moment generated at the pile head.

JP2000-144663 JP 2002-317454 A

  However, the above-described unbonding process requires labor and cost to cut a deformed stud or dispose a cylindrical body, and there is room for improvement from an economical viewpoint. Above all, steel rods such as deformed studs, reinforcing bars or anchor bolts corrode and expand over time due to the neutralization of concrete and the like, resulting in adhesion to concrete due to the corrosion expansion. The problem was that it was difficult to maintain.

  Moreover, even if a structure capable of allowing the rotational deformation at the pile head and reducing the generated bending moment is temporarily adopted, the conventional design method that regards the pile head joint as a rigid connection is actually Since the fixed degree is often smaller than 1, the bending moment distribution generated in the pile is different from that at the time of design. The pile head is smaller than the design value, but the intermediate portion is larger than the design value. There was a problem that there was a concern that caused the destruction of the pile.

  The present invention has been made in consideration of the above-described circumstances, and can reduce the fixing degree of the pile head joint portion without performing an unbonding process and can perform an appropriate design according to the reduction of the fixing degree. The purpose is to provide a design method.

  In order to achieve the above object, the pile design method according to the present invention includes a pile having a head joined to an upper structure via a predetermined joining material and supporting the upper structure. A method of designing,

  The joining material is composed of a fixing degree reducing flat plate joined to an end plate provided at the head of the pile, and an anchor bolt standing on the fixing degree reducing flat plate and embedded in the upper structure. And when a horizontal force acts on the head of the pile from the superstructure, the fixing degree reducing flat plate is bent out of plane and configured to rotate the head of the pile,

  Set the specifications of the bonding material,

Evaluate the allowable bending moment M _a at the head of the pile,

The pile head rotation angle θ when the allowable bending moment M _a acts on the head of the pile, the following equation,

θ = (Δb + Δp) / (Dp / 2 + r _s −x _no ) (1-a)

        Δb: Elongation amount of anchor bolt on the tension side

        Δp: Bending deformation amount of flat plate for fixing degree reduction

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

Calculated by

Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:

K _θ = M _a / θ (2)

Calculated by

Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,

The reduced generated bending moment _Mθ is used to determine the specifications of the bonding material.

  Moreover, the design method of the pile which concerns on this invention replaces with the said (1-a) type | formula,

θ = (Δb + Δp + Δα) / (Dp / 2 + r _s −x _no ) (1′−a)

        Δα: Compression deformation or rotational deformation of the pile cap (in the superstructure, near the pile head where the anchor bolt is buried)

It is what.

  In addition, the pile designing method according to the present invention is a method for designing a pile that supports the upper structure with the head bonded to the upper structure via a predetermined bonding material. And

  The joining material is composed of a fixing degree reducing member attached to an end plate provided on the head of the pile, and an anchor bolt attached to the fixing degree reducing member and embedded in the upper structure, and A non-flat portion such as a stepped portion or a rising portion is formed on the fixing degree reducing member between the attachment position to the end plate and the attachment position to the anchor bolt, and horizontal force is generated from the superstructure to the pile. When the head of the pile is acted, the fixing degree reducing member is bent and deformed, and the head of the pile is configured to rotate,

  Set the specifications of the bonding material,

Evaluate the allowable bending moment M _a at the head of the pile,

The pile head rotation angle θ when the allowable bending moment M _a is applied to the pile head joint, the following equation,

θ = (Δb + Δpb) / (Dp / 2 + r _s −x _no ) (1-b)

        Δb: Elongation amount of anchor bolt on the tension side

        Δpb: Bending deformation amount of fixedness reduction member

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

Calculated by

Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:

K _θ = M _a / θ (2)

Calculated by

Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,

The reduced generated bending moment _Mθ is used to determine the specifications of the bonding material.

  Moreover, the design method of the pile which concerns on this invention replaces with said (1-b) Formula,

θ = (Δb + Δpb + Δα) / (Dp / 2 + r _s −x _no ) (1′−b)

        Δα: Compression deformation or rotational deformation of the pile cap (in the superstructure, near the pile head where the anchor bolt is buried)

It is what.

  In addition, the pile design method according to the present invention is a method for designing a pile that supports the upper structure with the head bonded to the upper structure via a predetermined bonding material as described in claim 5. And

  The straight portion extending to one side of the bonding material is attached to an end plate provided on the head of the pile, and the straight portion extending to the other side via an L-shaped fixing degree reducing portion is the upper structure. And when the horizontal force acts on the head of the pile from the upper structure, the L-shaped fixing degree reducing portion is bent and deformed to cause the head of the pile to be embedded. Configured to rotate,

  Set the specifications of the bonding material,

Evaluate the allowable bending moment M _a at the head of the pile,

The pile head rotation angle θ when the allowable bending moment M _a acts on the head of the pile, the following equation,

θ = (Δb + Δpl) / (Dp / 2 + r _s −x _no ) (1-c)

        Δb: Elongation amount of anchor bolt on the tension side

        Δpl: Bending deformation of L-shaped fixed degree reduction part

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

Calculated by

Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:

K _θ = M _a / θ (2)

Calculated by

Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,

The reduced generated bending moment _Mθ is used to determine the specifications of the bonding material.

  Moreover, the design method of the pile which concerns on this invention replaces with the said (1-c) type | formula,

θ = (Δb + Δpl + Δα) / (Dp / 2 + r _s −x _no ) (1′−c)

        Δα: Compression deformation or rotational deformation of the pile cap (in the superstructure, near the pile head where the anchor bolt is buried)

It is what.

  In addition, the pile designing method according to the present invention is a method for designing a pile that supports the upper structure with the head bonded to the upper structure via a predetermined bonding material. And

  The joining material is composed of an end plate provided on the head of the pile, and an anchor bolt that is erected on the end plate and supported by the pile, and a horizontal force is When acting on the head of the pile from the superstructure, the end plate is configured to bend and deform out of plane and the head of the pile rotates.

  Set the specifications of the bonding material,

Evaluate the allowable bending moment M _a at the head of the pile,

The pile head rotation angle θ when the allowable bending moment M _a is applied to the pile head joint, the following equation,

θ = (Δb + Δpe) / (Dp / 2 + r _s −x _no ) (1-d)

        Δb: Elongation amount of anchor bolt on the tension side

        Δpe: End plate bending deformation

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

Calculated by

Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:

K _θ = M _a / θ (2)

Calculated by

Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,

The reduced generated bending moment _Mθ is used to determine the specifications of the bonding material.

  Moreover, the design method of the pile which concerns on this invention replaces with said (1-d) type | formula,

θ = (Δb + Δpe + Δα) / (Dp / 2 + r _s −x _no ) (1′−d)

        Δα: Compression deformation or rotational deformation of the pile cap (in the superstructure, near the pile head where the anchor bolt is buried)

It is what.

  In the pile designing method according to the present invention, first, the specifications of the bonding material are set.

  Here, the joining material according to the first aspect of the present invention is a fixed degree reducing flat plate to be joined to an end plate provided at the head of the pile, and is erected on the fixed degree reducing flat plate and embedded in the upper structure. The anchor bolt is configured so that when the horizontal force acts on the pile head from the superstructure, the fixation reduction flat plate is bent out of plane and the pile head rotates. It is.

  Moreover, the joining material which concerns on 2nd invention consists of the anchorage reduction member attached to the end plate provided in the head of a pile, and the anchor bolt embed | buried in the upper structure attached to this fixation degree reduction member. In addition to the structure, non-flat parts such as stepped parts and rising parts are formed in the fixing degree reduction member between the attachment points to the end plates and the anchor bolts, and the horizontal force is the upper structure. When acting on the head of the pile, the fixing degree reducing member is bent and deformed so that the head of the pile rotates.

  Moreover, the joining material which concerns on 3rd invention is attached to the end plate provided in the head of the said pile, and the linear part extended to one side is extended to the other side via an L-shaped fixation degree reduction part. The straight part is configured to be an anchor bolt embedded in the upper structure, and when a horizontal force acts on the head of the pile from the upper structure, the L-shaped fixing degree reduction part is bent and deformed, and the pile The head is configured to rotate.

  The joining material according to the fourth invention comprises an end plate provided at the head of the pile and an anchor bolt embedded in the upper structure that is erected on the end plate and supported by the pile. When the horizontal force acts on the head of the pile from the upper structure, the end plate is bent out of plane and the head of the pile is rotated.

  The piles are mainly pre-made piles such as PRC piles, PC piles, PHC piles, steel pipe piles, RC piles, SC piles, etc. However, as long as each joint material described above can be attached to the head, the type is arbitrary. It may be a cast in place.

  As the anchor bolt, a steel rod formed of a predetermined steel material can be appropriately adopted. As a method of standing on the fixing degree reducing flat plate, the fixing degree reducing member, and the end plate, either welding or screwing can be used. Can be selected. Moreover, although it is arbitrary about the cross-sectional shape of an anchor bolt, a round steel can be employ | adopted typically.

  Among the joining materials, the specifications of the fixing degree reducing flat plate, the fixing degree reducing member, and the end plate can include, for example, the planar shape, thickness, steel material type, deformation restraint position, that is, the installation position of the anchor bolt. . For example, the specification of the anchor bolt may include the number of attachments, the diameter, and the embedded length. The building design, pile arrangement, ground constant, pile design shear force, short pile force for pile design and bending moment for pile design are determined in advance.

If the specification of the joining material is set, next, the allowable bending moment M _a at the head of the pile is evaluated.

Here, the allowable bending moment M _{a at} the head of the pile can be appropriately calculated by a known procedure, and may be appropriately corrected based on known knowledge obtained through experiments or the like. It doesn't matter. In this specification, it is included to modify the reduction rate and the like is reflected, and those using allowable bending moment M _a term.

Next, the allowable bending moment M _a is a pile head rotation angle θ when the acting on the head of the pile, (1-a) expression, (1-b) formula, (1-c) type or (1-d ).

Here, [Delta] b, as described above, an elongation of the tension side of the anchor bolt when the allowable bending moment M _a acts on the head of the pile, embedded length and cross-sectional area of the anchor bolt or the base member, The degree of adhesion (unbonded or bonded) may be appropriately taken into consideration and calculated or evaluated by a known method.

Delta] p, .DELTA.PB, [Delta] pl, respectively .DELTA.Pe, fixed degree reduced flat plates when permissible bending moment M _a acts on the head of the pile, due to bending deformation of the fixing degree reducing member, L-shaped fixing degree reduction unit and the end plate The amount of deformation, which is the amount of deformation at the anchor bolt position along the material axis direction of the anchor bolt, and the shape and thickness of the fixing degree reducing flat plate, the fixing degree reducing member, the L-shaped fixing degree reducing portion, and the end plate The calculation or evaluation may be performed by a known method with appropriate considerations.

Next, using the calculated pile head rotation angle θ, the rotational rigidity K _θ is _expressed by the following equation:

K _θ = M _a / θ (2)

Calculated by

Here, the rotational stiffness K _theta, a stiffness of only speak pile joints corresponding to the allowable bending moment M _a, the rigidity of the rigidity and ground piles themselves are not included.

Next, the generated bending moment _Mθ is calculated using the rotational rigidity _Kθ . The generated moment M _θ is reduced by an amount corresponding to the rotational rigidity K _θ compared to the previous generated bending moment M ₀ , where the degree of fixation is regarded as 1. In addition, it is possible to use a well-known calculation formula about the method itself for calculating the generated bending moment _Mθ . For example, when the ground on which the pile is placed can be regarded as a homogeneous ground (uniform ground), The following formula,

_{M θ = M 0 · K θ} / (EIβ + K θ) (3)

M ₀ ; Generated bending moment when the fixing degree is 1

          EI: Bending stiffness of pile

          β: Ground condition and coefficient determined from pile (horizontal resistance characteristic value of pile)

Can be calculated.

Next, to determine the specifications of the bonding material by using thus calculated generated bending moment M _theta.

  According to the pile design method described above, the rotation of the pile head joint is determined from the elongation of the anchor bolt and the amount of bending deformation of the fixing degree reducing flat plate, the fixing degree reducing member, the L-shaped fixing degree reducing part or the end plate. By evaluating the deformation, it is possible to determine the specifications of the bonding material that can reduce the bending moment generated at the pile head.

  Hereinafter, an embodiment of a pile designing method according to the present invention will be described with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

(First embodiment)

  FIGS. 1 and 2 are flowcharts showing a method for designing a pile according to the present embodiment, and FIGS. 3 and 4 are perspective views showing a joint material to be subjected to the design method and a pile head joint structure using the joint material. It is a figure, a top view, and sectional drawing.

  As can be seen from FIGS. 3 and 4, the bonding material 1 according to the present embodiment includes a fixing degree reducing flat plate 2 and anchor bolts 3 erected on the fixing degree reducing flat plate, and the bonding material 1. The pile head joint structure 4 using the bolt 10 is a bolt 10 in a state in which the fixing degree reduction flat plate 2 is overlapped on an end plate 7 provided on a head 6 of a pile 5 which is a PHC pile (hereinafter referred to as a pile head 6). While being joined to the end plate, the anchor bolt 3 is embedded in a foundation member 9 such as a foundation beam, a foundation slab, or a columnar shape of the upper structure 8 supported by the pile 5.

The degree of fixing reduced flat plates 2 is equal outer radius R ₂ is an outer radius r ₂ of the pile 5, the inner radius R ₁ is Yes formed at an inner radius r ₁ steel small annular than the pile 5, the pile 5 The bolt 10 is inserted into the insertion hole 11 drilled at a position corresponding to the PC steel wire installation position, and is screwed into the bolt hole 12 formed in the end plate 2 so that the end plate 7 can be fixed.

  The fixing degree reduction flat plate 2 is provided with a bolt hole 13 through which the anchor bolt 3 is inserted, and the anchor bolt 3 is fixed by inserting the anchor bolt 3 into the bolt hole and screwing the nuts 14 and 14 together. It is possible to stand on the flat plate 2 for reducing the degree.

Here, the bolt hole 13 is positioned so that the distance from the cross-sectional center of the pile 5, in other words, the mounting radius R of the anchor bolt 3 is smaller than the inner diameter r _{1 of the} pile 5. With this configuration, the standing position of the anchor bolt 3 is on the inner side of the inner peripheral surface of the pile 5.

  The pile head joint structure 4 according to the present embodiment and the joining material 1 used for the pile head are overlapped on the end plate 7 of the pile head 6 when the earthquake horizontal force acts on the pile head 6 from the upper structure 9 by the above-described configuration. As shown in FIG. 5, the fixed degree reducing flat plate 2 joined together is bent and deformed out of the plane, and accordingly, the pile head 6 undergoes rotational deformation.

  Therefore, the joint degree of the pile head 6 with respect to the foundation member 9 is relaxed, and a so-called semi-rigid joint is obtained. In addition, the generated bending moment M with respect to the rotation angle θ of the pile head 6, in other words, the rotational rigidity of the pile head 6 can be evaluated as the out-of-plane bending rigidity of the fixing degree reducing flat plate 2.

  In the pile design method according to the present embodiment, first, the specification of the pile 5, the specification of the anchor bolt 3, and the specification of the fixation degree reducing flat plate 2 are set (step 101).

  Here, the specifications of the pile 5 are the contents of the pile diameter, the specifications of the anchor bolt 3 are the contents of the number of attachments, the diameter and the embedded length, and the specifications of the flat plate 2 for fixing degree reduction are the planar shape, thickness, steel material The type, deformation restraint position, that is, the installation position of the anchor bolt 3 (position of the bolt hole 13) is the content.

  In addition, the pile arrangement is appropriately determined in consideration of the building load, the ground conditions, etc., and the axial force N (maximum axial force Nmax, minimum axial force Nmin) acting on the pile 6 to be designed is determined in advance. The ground condition may be determined by, for example, conducting a boring survey to check the N value. The pile design shear force, the pile design short-term axial force, and the pile design bending moment are also calculated in advance according to the input earthquake motion.

And specifications of the pile 5, and specifications of the anchor bolt 3, if the specification of the fixed degree reduced flat plates 2 is set, then, to evaluate the allowable bending moment M _a in the head of the pile (step 102). Note that the allowable bending moment M _a, may be suitably calculated by known procedures.

Next, as shown in FIG. 6, the pile head rotation angle θ when the allowable bending moment M _a acts on the pile head, the following equation,

θ = (Δb + Δp) / (Dp / 2 + r _s −x _no ) (1-a)

        Δb: Elongation amount of anchor bolt on the tension side

        Δp: Bending deformation amount of flat plate for fixing degree reduction

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

(Step 103).

Here, [Delta] b, as described above, an elongation of the anchor bolt 3 of the tensile side when permissible bending moment M _a acts on the head of the pile 6, Ya embedded length of the anchor bolt 3 to the base member 9 The cross-sectional area or the degree of adhesion to the base member 9 (unbonded or bonded) may be appropriately taken into consideration and calculated or evaluated by a known method.

Δp is a deformation amount by bending deformation of the fixed degree reduced flat plates 2 when permissible bending moment M _a acts on the pile head 6, the amount of deformation of the anchor bolt positions along the timber axis of the anchor bolt 3 The shape, thickness, etc. of the fixing degree reducing flat plate 2 may be appropriately taken into consideration and calculated or evaluated by a known method.

Next, using the calculated pile head rotation angle θ, the rotational rigidity K _θ is _expressed by the following equation:

K _θ = M _a / θ (2)

(Step 104).

Here, the rotational stiffness K _theta, a stiffness of only speak pile joints corresponding to the allowable bending moment M _a, the rigidity of the rigidity and ground piles themselves are not included.

Next, the generated bending moment _Mθ is calculated using the calculated rotational stiffness _Kθ . In this embodiment, the ground on which the pile is placed can be regarded as a homogeneous ground (uniform ground). ,

_{M θ = M 0 · K θ} / (EIβ + K θ) (3)

M ₀ ; Generated bending moment when the fixing degree is 1

          EI: Bending stiffness of pile

          β: Ground condition and coefficient determined from pile (horizontal resistance characteristic value of pile)

(Step 105).

Next, the generated bending moment M _θ calculated in this way is a value that takes into account the rotational rigidity of the pile head joint and the rigidity of the pile itself and the ground, so that the allowable bending moment M _a Does not match.

Therefore, the reduced generated bending moment M _θ is _expressed by the following equation:

M _θ ≦ M _a (4)

It is determined whether or not the condition is satisfied (step 106).

  Next, when the formula (4) is not satisfied (step 106, NO), at least one of the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing flat plate 2 is reset ( Step 107), the steps after step 102 are repeated.

On the other hand, in the determination (4) If the equation is satisfied (step 106, YES), further, if M _a is not excessively too large than M _theta, to determine if they are the overspecification other words If it can be determined that it is over-spec (step 108, NO), at least one of the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the flat plate 2 for reducing the fixing degree is reset ( Step 109), the process after step 102 is repeated.

On the other hand, if it can be determined that the over-spec is not reached (step 108, YES), the bending moment M _P generated in the pile 5 is calculated using the reduced generated bending moment M _θ and the pile design shear force S,

Bending moment M _p ≦ Allowable bending moment M _{pa of} pile 5 (5)

Is determined over the entire length of the pile 5 (step 110).

  Next, when the formula (5) is not satisfied (step 110, NO), at least one of the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing flat plate 2 is reset ( Step 111), the steps after Step 102 are repeated.

Here, when the bending moment M _p generated in the main body of the pile 5 is larger than the allowable bending moment M _pa of the pile 5, the bending moment distribution of the pile is larger not in the pile head but in the middle portion of the pile. Therefore, it is only necessary to reset at least one of the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing flat plate 2.

On the other hand, when the expression (5) is satisfied (step 110, YES), the allowable bending moment M _pa of the pile 5 is not excessively larger than the bending moment M _p , in other words, it is not over-spec. If it can be determined that it is over spec (step 112, NO), at least one of the specifications of the pile 5, the specifications of the anchor bolt 3 and the flat plate 2 for fixing degree reduction Is reset (step 113), and the processes after step 102 are repeated.

Here, the bending moment M _p occurs in the body of the pile 5, too small than the allowable bending moment M _pa piles 5, the bending moment distribution of the piles is greater at the pile head rather than pile intermediate portion. Therefore, it is only necessary to reset at least one of the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing flat plate 2.

  On the other hand, when it can be determined that it is not over-spec (step 112, YES), the specification of the pile 5 defined first, the specification of the anchor bolt 3 and the specification of the flat plate 2 for fixing degree reduction are respectively the specification of the pile 5, The specifications of the anchor bolt 3 and the specifications of the fixing degree reducing flat plate 2 are determined (step 114).

  As described above, according to the pile designing method according to the present embodiment, the degree of fixing of the pile head 6 to the foundation member 9 is greatly relaxed compared to the conventional case, and the pile design in which so-called semi-rigid joining is realized is appropriately applied. Can be performed.

  That is, according to the present embodiment, not only the elongation of the anchor bolt 3 but also the bending degree of the fixing degree reducing flat plate 2 significantly reduces the fixing degree of the pile head 6 and the bending degree of the fixing degree reducing flat plate 2 is also reduced. By evaluating the rotational deformation of the pile head 6 from the deformation and the elongation of the anchor bolt 3, it is possible to appropriately determine the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing flat plate 2.

  Moreover, according to the design method of the pile which concerns on this embodiment, even if it is a case where (4) Formula and (5) Formula are materialized, when it can be judged that it is an over specification, the specification of a pile 5, an anchor Since the specification of the bolt 3 and the specification of the fixing degree reducing flat plate 2 are reset and the process after step 102 is repeated, it becomes possible to perform a more rational and economical design.

In the present embodiment, when calculating the generated bending moment M _theta, as piles may be considered ground homogeneous soil that is pouring (uniformly ground), (3) was calculated by the equation, generated bending moment M _theta The calculation of itself may be appropriately selected from known calculation formulas according to the ground conditions. For example, when the ground is a multi-layer ground, the generated bending moment M _θ may be calculated using the calculation formula corresponding to the calculation formula.

  Further, in this embodiment, the anchor bolt 3 is erected on the fixing degree reduction flat plate 2 by bolt joining using the nuts 14, 14, but instead, the lower end of the anchor bolt 3 is reduced in fixing degree. The anchor bolt 3 may be erected on the fixing degree reducing flat plate 2 by welding to the upper surface of the flat plate 2 for use.

  In the present embodiment, the fixing degree reducing flat plate 2 is bolted to the end plate 7. However, the fixing degree reducing flat plate 2 may be welded instead of the bolt.

Moreover, in this embodiment, although the standing position of the anchor bolt 3 was set inside the inner peripheral surface of the pile 5, it may be set outside the outer peripheral surface of the pile 5 instead. That is, the bolt hole 13 through which the anchor bolt 3 is inserted is positioned such that the distance from the center of the cross section of the pile 5, in other words, the mounting radius R of the anchor bolt 3 is larger than the outer radius r _{2 of the} pile 5.

  FIG. 7 is a diagram showing how the fixing degree reducing flat plate 42 with the bolt holes 13 positioned in this way undergoes out-of-plane bending deformation. As can be seen from the figure, even in this modification, the rotational rigidity of the pile head 6 can be evaluated as the out-of-plane bending rigidity of the fixing degree reducing flat plate 42. The rotational rigidity of the pile head 6 can be calculated only with various data relating to the flatness 42 for fixing degree reduction, and the degree of fixing degree reduction in the pile head 6 can be easily grasped.

  Further, although not particularly mentioned in the present embodiment, the fixing degree reducing flat plate 2 does not have to be a single plate. For example, as shown in FIGS. 8 and 9, the whole is an annular shape and each has a fan shape. The fixing degree reducing flat plate 52 may be constituted by the four divided pieces 53, and the anchor bolts 3 may be erected on each of the divided pieces 53.

  Even in such a configuration, in addition to the same effects as the above-described embodiment, each split piece 53 individually generates out-of-plane bending deformation, so that it becomes easy to grasp the entire out-of-plane bending deformation, and the joining at the pile head 6 The degree reduction evaluation becomes easier.

  Although not specifically mentioned in the present embodiment, for example, as shown in FIG. 10, four slits 73 formed in an annular shape and extending radially outward from the inner edge are formed at 90 ° positions and fixed. The degree reducing flat plate 72 may be configured, and the anchor bolts 3 may be erected on the four tongues 74 sandwiched between the slits.

  Even in such a configuration, the same effects as the above-described embodiment can be obtained, and each tongue-like body 74 individually generates out-of-plane bending deformation, so that it becomes easy to grasp the entire out-of-plane bending deformation, and in the pile head 6 The reduction evaluation of the degree of joining becomes easy.

  Similarly, as shown in FIG. 11, a fixing degree reducing flat plate 82 is constituted by four tongue pieces 83 each formed by extending a semicircular portion to a short edge portion of a rectangular portion, and these four tongue pieces. 83 may be overlapped and joined to the end plate 7 every 90 °, and the anchor bolts 3 may be erected on the semicircular portions of the respective tongue pieces.

  Even in such a configuration, the same effects as the above-described embodiment can be obtained, and each tongue piece 83 individually generates out-of-plane bending deformation, so that it becomes easy to grasp the entire out-of-plane bending deformation, and the joining at the pile head 6 The degree reduction evaluation becomes easy.

  Further, in this embodiment, when calculating the rotational deformation of the pile head, only the elongation amount of the anchor bolt on the tension side and the bending deformation amount of the flat plate for reducing the fixing degree are taken into consideration.

θ = (Δb + Δp + Δα) / (Dp / 2 + r _s −x _no ) (1′−a)

Therefore, the amount of compressive deformation or the amount of rotational deformation of the pile cap (the vicinity of the pile head where the anchor bolt is embedded in the upper structure) may be taken into consideration.

(Second Embodiment)

  Next, a second embodiment will be described. Note that steps substantially the same as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  12 and 13 are a perspective view, a plan view, and a cross-sectional view showing a joining material that is a target of the pile designing method according to the present embodiment and a pile head joining structure using the joining material. As can be seen from the figure, the bonding material 201 according to the present embodiment includes the fixing degree reducing member 202 and the anchor bolt 3 attached to the fixing degree reducing member, and the pile head joining structure 204 according to the present embodiment. The fixing degree reducing member 202 is joined to the end plate 7 provided on the head 6 of the pile 5 which is a PHC pile (hereinafter referred to as the pile head 6) with a bolt 10 and is supported by the pile 5 The anchor bolt 3 is embedded in the base member 9 of the structure 8.

  The fixing degree reducing member 202 includes four tongue pieces 202a having a strip shape in plan view, and insertion holes 211 and 211 through which the bolts 10 are inserted are formed at one end of each tongue piece. The fixing degree reducing member 202 can be fixed to the end plate 7 by screwing the bolt 10 inserted through the hole into the bolt hole 12 formed in the end plate 7.

  Also, a bolt hole 213 is provided at the other end of the tongue piece 202a, and the anchor bolt 3 is inserted into the bolt hole and the nuts 14 and 14 are screwed together, whereby the anchor bolt 3 is attached to the fixing degree reducing member 202. It can be attached.

  Therefore, although the insertion holes 211 and 211 are places where the end plate 7 is attached, and the bolt holes 213 are places where the anchor bolt 3 is attached, the places where the end plate 7 is attached and places where the anchor bolt 3 is attached In the middle, a step 215 as a non-flat part formed by bending is provided.

Here, the bolt hole 213 is positioned such that the distance from the cross-sectional center of the pile 5, in other words, the attachment radius R of the anchor bolt 3 is smaller than the inner radius r _{1 of the} pile 5. With this configuration, the standing position of the anchor bolt 3 is on the inner side of the inner peripheral surface of the pile 5.

  The pile head joint structure 204 according to the present embodiment and the joint material 201 used for the pile head are attached to the end plate 7 of the pile head 6 when the earthquake horizontal force acts on the pile head 6 from the upper structure 9 by the above-described configuration. As shown in FIG. 14, the fixed degree reducing member 202 is bent and deformed, and accordingly, the pile head 6 is rotationally deformed.

  Therefore, the joint degree of the pile head 6 with respect to the foundation member 9 is relaxed, and a so-called semi-rigid joint is obtained. In addition, the generated bending moment M with respect to the rotation angle θ of the pile head 6, in other words, the rotational rigidity of the pile head 6 can be evaluated as the bending rigidity of the fixing degree reducing member 202.

  In addition, since the plastic part is formed in the step part 215 by bending, the main bending deformation part in the four tongue pieces 202a constituting the fixing degree reducing member 202 is specified as the bending position of the step part 215. be able to.

  In the pile design method according to the present embodiment, first, as in step 101, the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing member 202 are set.

  Here, the specification of the pile 5 includes the diameter of the pile, the specification of the anchor bolt 3 includes the number of mountings, the diameter, and the embedded length, and the specification of the fixing degree reducing member 202 includes the shape of the stepped portion 215, The contents are thickness, steel material type, deformation restraint position, that is, the installation position of anchor bolt 3 (position of bolt hole 213).

  In addition, the pile arrangement is appropriately determined in consideration of the building load, the ground conditions, etc., and the axial force N (maximum axial force Nmax, minimum axial force Nmin) acting on the pile 6 to be designed is determined in advance. The ground condition may be determined by, for example, conducting a boring survey to check the N value. The pile design shear force, the pile design short-term axial force, and the pile design bending moment are also calculated in advance according to the input earthquake motion.

If the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing member 202 are set, next, as in step 102, the allowable bending moment M _a at the head of the pile is evaluated. The allowable bending moment M _a may be appropriately calculated by a known procedure.

Then, as in step 103, the pile head rotation angle θ when the allowable bending moment M _a acts on the pile head, the following equation,

θ = (Δb + Δpb) / (Dp / 2 + r _s −x _no ) (1-b)

        Δb: Elongation amount of anchor bolt on the tension side

        Δpb: Bending deformation amount of fixedness reduction member

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

Calculate with

Here, [Delta] b, as described above, an elongation of the anchor bolt 3 bending tension side when permissible bending moment M _a acts on the head of the pile 6, the embedding length of the anchor bolt 3 to the base member 9 It may be calculated or evaluated by a known method by appropriately taking into account the cross-sectional area, the degree of adhesion to the base member 9 (unbonded or bonded), and the like.

Δpb is a deformation amount by bending deformation of the fixed degree reducing member 202 when the allowable bending moment M _a acts on the pile head 6, a variation of anchor bolt positions along the timber axis of the anchor bolt 3 Yes, the shape, thickness, etc. of the fixing degree reducing member 202 may be appropriately taken into consideration and calculated or evaluated by a known method.

Then similar to step 104, and calculates the rotational stiffness K _theta by equation (2) using a pile head rotation angle theta calculated.

Next, similarly to step 105, the generated bending moment _Mθ is calculated using the calculated rotational stiffness _Kθ .

Next, as in step 106, it is determined whether the generated bending moment _Mθ satisfies the equation (4).

  Next, when the expression (4) is not satisfied, at least one of the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing member 202 is reset as in Step 107, and Step 102 is performed. Repeat the following steps.

On the other hand, if the above judgment (4) holds, further, or M _a is not excessively too large than M _theta, to determine if they are the overspecification other words, become overspecification If it can be determined that there is at least one of the specifications of the pile 5, the specifications of the anchor bolt 3 and the specifications of the fixing degree reducing member 202, as in step 109, the process from step 102 is repeated.

On the other hand, if it can be determined that the over-spec is not reached, the bending moment M _P generated in the pile 5 is calculated using the reduced generated bending moment M _θ and the pile design shear force S, as in step 110, ( 5) Determine whether the formula is valid over the entire length of the pile 5.

  Next, when the formula (5) is not satisfied, at least one of the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the fixing degree reducing member 202 is reset as in Step 111, and Step 102 is performed. Repeat the following steps.

On the other hand, if the formula (5) is satisfied, it is further determined whether the allowable bending moment M _pa of the pile 5 is not excessively larger than the bending moment M _p , in other words, whether it is over-specification, When it can be determined that it is over-spec, as in step 113, at least one of the specifications of the pile 5, the specifications of the anchor bolt 3 and the specifications of the fixing degree reducing member 202 is reset, and after step 102 Repeat the process.

  On the other hand, if it can be determined that it is not over-spec, as in step 114, the specification of the pile 5, the specification of the anchor bolt 3 and the specification of the fixing degree reducing member 202 that are initially determined are the specification of the pile 5, the anchor bolt, respectively. 3 and the specifications of the fixing degree reducing member 202 are determined.

  As described above, according to the pile designing method according to the present embodiment, the degree of fixing of the pile head 6 to the foundation member 9 is greatly relaxed compared to the conventional case, and the pile design in which so-called semi-rigid joining is realized is appropriately applied. Can be performed.

  That is, according to the present embodiment, not only the elongation of the anchor bolt 3 but also the bending degree of the fixing degree reducing member 202 significantly reduces the fixing degree of the pile head 6, and the bending degree of the fixing degree reducing member 202 and By evaluating the rotational deformation of the pile head 6 from the elongation of the anchor bolt 3, the specification of the pile 5, the specification of the anchor bolt 3, and the specification of the fixing degree reducing member 202 can be appropriately determined.

  Moreover, according to the design method of the pile which concerns on this embodiment, even if it is a case where (4) Formula and (5) Formula are materialized, when it can be judged that it is an over specification, the specification of a pile 5, an anchor Since the specification of the bolt 3 and the specification of the fixing degree reducing member 202 are reset and the process after step 102 is repeated, a more rational and economical design can be performed.

  In the present embodiment, the anchor bolt 3 is erected on the fixing degree reducing member 202 by bolt joining using the nuts 14 and 14, but instead, the lower end of the anchor bolt 3 is placed on the upper surface of the tongue piece 202a. The anchor bolt 3 may be erected on the fixing degree reducing member 202 by welding.

  Further, in this embodiment, the fixing degree reducing member 202 is bolted to the end plate 7, but may be joined by welding instead of bolting.

Moreover, in this embodiment, although the standing position of the anchor bolt 3 was set inside the inner peripheral surface of the pile 5, it may be set outside the outer peripheral surface of the pile 5 instead. That is, the bolt hole 13 through which the anchor bolt 3 is inserted is positioned such that the distance from the center of the cross section of the pile 5, in other words, the mounting radius R of the anchor bolt 3 is larger than the outer radius r _{2 of the} pile 5. For example, by reversing the attachment angle of each tongue piece 202a to the end plate 7 in the above-described embodiment by 180 °, each tongue piece 202a is directed radially outward, and this is used as a fixing degree reducing member according to this modification. It can be.

  Even in such a modified example, the rotational rigidity of the pile head 6 can be evaluated as the bending rigidity of the fixing degree reducing member, and as with the above-described embodiment, only the various data relating to the fixing degree reducing member can be evaluated. The rotational rigidity of the pile head 6 can be calculated, and the degree of fixing degree reduction in the pile head 6 can be easily grasped.

  Although not particularly mentioned in the present embodiment, the fixing degree reducing member according to the present invention may be configured as shown in FIG. That is, the fixing degree reducing member 242 shown in the figure is composed of four L-shaped cross-section members 242a in which rising portions 243 as non-flat portions are formed. Here, a coupler 244 is welded to the back surface of the rising portion 243, and the four screw reinforcing bars 3a can be fixed to the fixing degree reducing member 242 by screwing the screw reinforcing bars 3a as anchor bolts into the coupler. It can be done.

  This modification also provides the same operational effects as the above-described embodiment, but the description thereof is omitted here.

  Moreover, in this embodiment, when calculating the rotational deformation of the pile head, only the amount of elongation of the anchor bolt on the tension side and the amount of bending deformation of the fixing degree reducing member were considered, but in addition to this, the following equation:

θ = (Δb + Δpb + Δα) / (Dp / 2 + r _s −x _no ) (1′−b)

Thus, the compression deformation amount or rotational deformation amount of the pile cap may be taken into consideration.

  Further, although not particularly mentioned in the present embodiment, the bonding material according to the present invention may be configured as shown in FIG. That is, the bonding material 252 shown in the figure is attached to the end plate 7 provided on the pile head 6 with the linear portion 253 extending on one side, and extends to the other side via the L-shaped fixing degree reducing portion 254. The straight portion 255 serves as an anchor bolt embedded in the foundation member 9.

  The joining material 252 is configured such that when the horizontal force during an earthquake acts on the pile head 6 from the upper structure 8, the L-shaped fixing degree reducing portion 254 is bent and deformed to rotate the pile head. The L-shaped fixing degree reduction unit 254 is preferably formed by bending as in the above-described embodiment.

  In this way, since the generated bending moment with respect to the rotational deformation of the pile head 6, in other words, the rotational rigidity can be evaluated as the bending rigidity of the L-shaped fixing degree reducing unit 254, the shape and the steel material type, the deformation constraint It is possible to calculate the rotational rigidity of the pile head only with various data related to the L-shaped fixing degree reduction unit 254 such as the position, that is, the installation position of the anchor bolt, and thus easily grasp the degree of fixing degree reduction at the pile head. be able to.

  In such a modification, instead of the formula (1-b),

θ = (Δb + Δpl) / (Dp / 2 + r _s −x _no ) (1-c)

        Δb: Elongation amount of anchor bolt on the tension side

        Δpl: Bending deformation of L-shaped fixed degree reduction part

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

However, except for this point, the procedure of the design method is the same as that of the above-described embodiment, and thus the description thereof is omitted here.

  In addition, in this modification, when calculating the rotational deformation of the pile head, only the elongation amount of the anchor bolt on the tension side and the bending deformation amount of the L-shaped fixing degree reduction part were taken into account. formula,

θ = (Δb + Δpl + Δα) / (Dp / 2 + r _s −x _no ) (1′−c)

Thus, the compression deformation amount or rotational deformation amount of the pile cap may be taken into consideration.

(Third embodiment)

  Next, a third embodiment will be described. Note that steps substantially the same as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIGS. 17 and 18 are a perspective view, a plan view, and a cross-sectional view showing a joining material that is a target of the pile designing method according to the present embodiment and a pile head joining structure using the joining material. As can be seen from the figure, the bonding material 301 according to the present embodiment includes an end plate 302 and anchor bolts 3 erected on the end plate, and the pile head bonding structure 304 according to the present embodiment includes an end plate 302. The plate 302 is provided on the pile head 6 that is a PHC pile, and the anchor bolt 3 is embedded in the foundation member 9 of the upper structure 8 supported by the pile 5.

The end plate 302 is formed of an annular steel material having an outer radius R ₂ equal to the outer radius r _{2 of the} pile 5 and an inner radius R ₁ smaller than the inner radius r _{1 of the} pile 5. When the pile 5 is manufactured, it is fixed to the pile head 6 by a known means.

  The end plate 302 is provided with a bolt hole 13 into which the anchor bolt 3 is inserted. The anchor bolt 3 is inserted into the bolt hole and the nuts 14 and 14 are screwed together, whereby the anchor bolt 3 is attached to the end plate 302. It can be erected.

Here, the bolt hole 13 is positioned such that the distance from the center of the cross section of the pile 5, in other words, the mounting radius R of the anchor bolt 3 is smaller than the inner radius r _{1 of the} pile 5. With this configuration, the standing position of the anchor bolt 3 is on the inner side of the inner peripheral surface of the pile 5.

  The pile head joint structure 304 according to the present embodiment and the joint material 301 used therefor are end plates provided on the pile head 6 when the horizontal force during an earthquake acts on the pile head 6 from the upper structure 8 by the above-described configuration. As shown in FIG. 19, 302 is bent and deformed out of the plane, and accordingly, the pile head 6 undergoes rotational deformation.

  Therefore, the joint degree of the pile head 6 with respect to the foundation member 9 is relaxed, and a so-called semi-rigid joint is obtained. In addition, the generated bending moment M with respect to the rotation angle θ of the pile head 6, in other words, the rotational rigidity of the pile head 6 can be evaluated as the out-of-plane bending rigidity of the end plate 302.

  In the pile design method according to the present embodiment, first, as in step 101, the specification of the pile 5, the specification of the anchor bolt 3, and the specification of the end plate 302 are set.

  Here, the specifications of the pile 5 are the contents of the pile diameter, the specifications of the anchor bolt 3 are the contents of the number of attachments, the diameter and the embedding length, and the specifications of the end plate 302 are the shape, thickness, steel material type, deformation restraint. The position, that is, the installation position of the anchor bolt 3 (the position of the bolt hole 13) is the content thereof.

  In addition, the pile arrangement is appropriately determined in consideration of the building load, the ground conditions, etc., and the axial force N (maximum axial force Nmax, minimum axial force Nmin) acting on the pile 6 to be designed is determined in advance. The ground condition may be determined by, for example, conducting a boring survey to check the N value. The pile design shear force, the pile design short-term axial force, and the pile design bending moment are also calculated in advance according to the input earthquake motion.

And specifications of the pile 5, and specifications of the anchor bolt 3, if the specifications of the end plate 302 is set, then, as in step 102, to evaluate the allowable bending moment M _a in the head of the pile. The allowable bending moment M _a may be appropriately calculated by a known procedure.

Then, as in step 103, the pile head rotation angle θ when the allowable bending moment M _a acts on the pile head, the following equation,

θ = (Δb + Δpe) / (Dp / 2 + r _s −x _no ) (1-d)

        Δb: Elongation amount of anchor bolt on the tension side

        Δpe: End plate bending deformation

        Dp: outer diameter of the pile

r _s; placement of the anchor bolt radius

x _no : distance from the compression edge of the cross section to the neutral axis position

Calculate with

Here, [Delta] b, as described above, an elongation of the anchor bolt 3 bending tension side when permissible bending moment M _a acts on the head of the pile 6, the embedding length of the anchor bolt 3 to the base member 9 It may be calculated or evaluated by a known method by appropriately taking into account the cross-sectional area, the degree of adhesion to the base member 9 (unbonded or bonded), and the like.

Δpe is a deformation amount due to bending deformation of the end plate 302 when the allowable bending moment M _a acts on the pile head 6, a deformation amount of anchor bolt positions along the timber axis of the anchor bolt 3, The shape, thickness, etc. of the end plate 302 may be appropriately taken into consideration and calculated or evaluated by a known method.

Then similar to step 104, and calculates the rotational stiffness K _theta by equation (2) using a pile head rotation angle theta calculated.

Next, similarly to step 105, the generated bending moment _Mθ is calculated using the calculated rotational stiffness _Kθ .

Next, as in step 106, it is determined whether the generated bending moment _Mθ satisfies the equation (4).

  Next, when the formula (4) is not established, at least one of the specifications of the pile 5, the specifications of the anchor bolt 3 and the specifications of the end plate 302 is reset as in Step 107, and Step 102 and the subsequent steps. Repeat steps.

On the other hand, if the above judgment (4) holds, further, or M _a is not excessively too large than M _theta, to determine if they are the overspecification other words, become overspecification If it can be determined that there is at least one of the specifications of the pile 5, the specifications of the anchor bolt 3 and the specifications of the end plate 302, as in step 109, the process from step 102 is repeated.

On the other hand, if it can be determined that the over-spec is not reached, the bending moment M _P generated in the pile 5 is calculated using the reduced generated bending moment M _θ and the pile design shear force S, as in step 110, ( 5) Determine whether the formula is valid over the entire length of the pile 5.

  Next, when the formula (5) is not satisfied, at least one of the specifications of the pile 5, the specifications of the anchor bolt 3 and the specifications of the end plate 302 is reset as in the step 111, and after the step 102 Repeat steps.

On the other hand, if the formula (5) is satisfied, it is further determined whether the allowable bending moment M _pa of the pile 5 is not excessively larger than the bending moment M _p , in other words, whether it is over-specification, If it can be determined that it is over-spec, as in step 113, at least one of the specifications of the pile 5, the specifications of the anchor bolt 3 and the specifications of the end plate 302 is reset, and the process after step 102 is performed. repeat.

  On the other hand, when it can be determined that the over-spec is not reached, the specification of the pile 5, the specification of the anchor bolt 3, and the specification of the end plate 302, which are determined initially, are the same as the specification of the pile 5 and The specifications and the specifications of the end plate 302 are determined.

  As described above, according to the pile designing method according to the present embodiment, the degree of fixing of the pile head 6 to the foundation member 9 is greatly relaxed compared to the conventional case, and the pile design in which so-called semi-rigid joining is realized is appropriately applied. Can be performed.

  That is, according to the present embodiment, not only the elongation of the anchor bolt 3 but also the bending deformation of the end plate 302 remarkably eases the fixing degree of the pile head 6, and the bending deformation of the end plate 302 and the anchor bolt 3. By evaluating the rotational deformation of the pile head 6 from the elongation, it is possible to appropriately determine the specifications of the pile 5, the specifications of the anchor bolt 3, and the specifications of the end plate 302.

  Moreover, according to the design method of the pile which concerns on this embodiment, even if it is a case where (4) Formula and (5) Formula are materialized, when it can be judged that it is an over specification, the specification of a pile 5, an anchor Since the specification of the bolt 3 and the specification of the end plate 302 are reset and the processes after step 102 are repeated, it becomes possible to perform a more rational and economical design.

  In the present embodiment, the anchor bolt 3 is erected on the end plate 302 by bolt joining using the nuts 14, 14. Instead, the lower end of the anchor bolt 3 is welded to the upper surface of the end plate 302. Thus, the anchor bolt 3 may be erected on the end plate 302.

Moreover, in this embodiment, although the standing position of the anchor bolt 3 was set inside the inner peripheral surface of the pile 5, it may be set outside the outer peripheral surface of the pile 5 instead. That is, the bolt hole 13a through which the anchor bolt 3 is inserted is positioned such that the distance from the center of the cross section of the pile 5, in other words, the mounting radius R of the anchor bolt 3 is larger than the outer radius r _{2 of the} pile 5.

  FIG. 20 is a diagram showing how the end plate 342 in which the bolt holes 13a are positioned in this way undergoes out-of-plane bending deformation. As can be seen from the figure, also in this modification, the rotational rigidity of the pile head 6 can be evaluated as the out-of-plane bending rigidity of the end plate 342, and the end plate 342 and the anchor are fixed as in the above-described embodiment. The rotational rigidity of the pile head 6 can be calculated only with various data relating to the bolt 3, and the degree of reduction in the degree of fixation at the pile head 6 can be easily grasped.

  Further, although not particularly mentioned in the present embodiment, the end plate 302 does not have to be a single plate. For example, as shown in FIGS. 21 and 22, the end plate 302 has an annular shape as a whole, and each has four fan shapes. The split plate 353 may constitute the end plate 352, and the anchor bolt 3 may be erected on each split piece 353.

  Even in such a configuration, in addition to the same effects as the above-described embodiment, each split piece 353 individually generates out-of-plane bending deformation, so that it becomes easy to grasp the entire out-of-plane bending deformation, and the joining at the pile head 6 The degree reduction evaluation becomes easier.

  Although not particularly mentioned in the present embodiment, for example, as shown in FIG. 23, four slits 373 that are formed in an annular shape and extend outward in the radial direction from the inner edge portion are formed at 90 ° intervals. The plate 372 may be configured, and the anchor bolts 3 may be erected on the four tongues 374 sandwiched between the slits.

  Even in such a configuration, the same effects as the above-described embodiment can be obtained, and each tongue-like body 374 individually generates out-of-plane bending deformation, so that it becomes easy to grasp the entire out-of-plane bending deformation, and in the pile head 6 The reduction evaluation of the degree of joining becomes easy.

  FIG. 24 shows a modification in which a total of eight anchor bolts 3 are erected on each of the four tongue bodies 374 sandwiched between the slits 373, and in this modification, the above-described embodiment and In addition to having the same effects, each tongue-like body 374 individually produces out-of-plane bending deformation, making it easy to grasp the entire out-of-plane bending deformation and facilitating a reduction evaluation of the degree of joint at the pile head 6.

  FIG. 25 shows an end plate 392 that is formed in an annular shape and has six slits 393 that extend radially inward from the outer edge portion every 60 °, and has six tongues sandwiched between the slits. 394 shows a modification in which six anchor bolts 3 are erected.

  Also in this modification, in addition to the same effects as the above-described embodiment, each tongue-like body 394 individually generates out-of-plane bending deformation, so that it becomes easy to grasp the entire out-of-plane bending deformation, and the pile head 6 This makes it easy to evaluate the reduction in the degree of bonding.

  Moreover, in this embodiment, when calculating the rotational deformation of the pile head, only the amount of elongation of the anchor bolt on the tension side and the amount of bending deformation of the end plate were considered, but in addition to this, the following equation:

θ = (Δb + Δpe + Δα) / (Dp / 2 + r _s −x _no ) (1′−d)

Thus, the compression deformation amount or rotational deformation amount of the pile cap may be taken into consideration.

The flowchart of the design method of the pile which concerns on this embodiment. The flowchart of the design method of the pile which similarly concerns on this embodiment. The disassembled perspective view of the bonding material used in this embodiment. It is a figure of a pile head junction structure to which this embodiment was applied, (a) is a top view and (b) is a vertical sectional view which meets an AA line. The figure which showed the effect | action of the pile head junction structure 4 to which this embodiment was applied, and the joining material 1 used for it. The schematic diagram for calculating the pile head rotation angle θ. The figure which showed the effect | action of the pile head junction structure which concerns on a modification. The disassembled perspective view of the joining material which concerns on a modification. It is a figure of the pile head junction structure concerning a modification, (a) is a top view, (b) is a vertical sectional view which meets a BB line. It is a figure of the pile head junction structure concerning a modification, (a) is a top view, (b) is a vertical sectional view which meets a CC line. It is a figure of the pile head junction structure concerning a modification, (a) is a top view, (b) is a perpendicular sectional view which meets a DD line. The disassembled perspective view of the bonding | jointing material 201 which concerns on this embodiment. It is a figure of the pile head junction structure 204 which concerns on this embodiment, (a) is a top view, (b) is a vertical sectional view which follows an EE line. The figure which showed the effect | action of the pile head junction structure 204 which concerns on this embodiment, and the joining material 201 used for it. It is a figure of the fixed degree reduction member 242 of the joining material which concerns on a modification, and a pile head joining structure using the same, (a) is a top view, (b) is a vertical sectional view which follows an FF line. It is the figure of the joining material 252 which concerns on a modification, and the pile head joining structure using the same, (a) is a top view, (b) is a vertical sectional view which follows a GG line. The disassembled perspective view of the joining material which concerns on this embodiment. It is a figure of the pile head junction structure concerning this embodiment, (a) is a top view, (b) is a vertical sectional view which follows a HH line. The figure which showed the effect | action of the pile head junction structure 304 which concerns on this embodiment, and the joining material 301 used for it. The figure which showed the effect | action of the pile head junction structure which concerns on a modification. The disassembled perspective view of the joining material which concerns on a modification. It is a figure of the pile head junction structure concerning a modification, (a) is a top view, (b) is a vertical sectional view which meets an II line. It is a figure of the pile head junction structure concerning a modification, (a) is a top view, (b) is a vertical sectional view which meets a JJ line. It is a figure of the pile head junction structure concerning a modification, (a) is a top view, (b) is a vertical sectional view which meets a KK line. It is a figure of the pile head junction structure concerning a modification, (a) is a top view, (b) is a vertical sectional view which meets a LL line.

Claims (8)

A method of designing a pile in which a head is bonded to an upper structure via a predetermined bonding material and supports the upper structure,
The joining material is composed of a fixing degree reducing flat plate joined to an end plate provided at the head of the pile, and an anchor bolt standing on the fixing degree reducing flat plate and embedded in the upper structure. And when a horizontal force acts on the head of the pile from the superstructure, the fixing degree reducing flat plate is bent out of plane and configured to rotate the head of the pile,
Set the specifications of the bonding material,
Evaluate the allowable bending moment M _a at the head of the pile,
The pile head rotation angle θ when the allowable bending moment M _a acts on the head of the pile, the following equation,
θ = (Δb + Δp) / (Dp / 2 + r _s −x _no ) (1-a)
Δb: Elongation amount of anchor bolt on the tension side Δp: Bending deformation amount of flat plate for fixing degree reduction Dp: Outer diameter of pile r _s ; Arrangement radius of anchor bolt x _no ; Distance from the compression edge of the cross section to the neutral axis position Calculate
Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:
K _θ = M _a / θ (2)
Calculated by
Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,
A method for designing a pile, wherein the specifications of the joint material are determined using the reduced generated bending moment _Mθ . Instead of the formula (1-a),
θ = (Δb + Δp + Δα) / (Dp / 2 + r _s −x _no ) (1′−a)
The pile design method according to claim 1, wherein Δα is a compressive deformation amount or a rotational deformation amount of a pile cap (a portion near a pile head where an anchor bolt is embedded in an upper structure). A method of designing a pile in which a head is bonded to an upper structure via a predetermined bonding material and supports the upper structure,
The joining material is composed of a fixing degree reducing member attached to an end plate provided on the head of the pile, and an anchor bolt attached to the fixing degree reducing member and embedded in the upper structure, and A non-flat portion such as a stepped portion or a rising portion is formed on the fixing degree reducing member between the attachment position to the end plate and the attachment position to the anchor bolt, and horizontal force is generated from the superstructure to the pile. When acting on the head of the
Set the specifications of the bonding material,
Evaluate the allowable bending moment M _a at the head of the pile,
The pile head rotation angle θ when the allowable bending moment M _a is applied to the pile head joint, the following equation,
θ = (Δb + Δpb) / (Dp / 2 + r _s −x _no ) (1-b)
Δb: Elongation amount of anchor bolt on the tension side Δpb: Bending deformation amount of the fixing degree reduction member Dp: Pile outer diameter r _s ; Anchor bolt arrangement radius x _no ; Calculated by the distance from the compression edge of the cross section to the neutral axis position And
Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:
K _θ = M _a / θ (2)
Calculated by
Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,
A method for designing a pile, wherein the specifications of the joint material are determined using the reduced generated bending moment _Mθ . Instead of the formula (1-b),
θ = (Δb + Δpb + Δα) / (Dp / 2 + r _s −x _no ) (1′−b)
The pile design method according to claim 3, wherein Δα is a compressive deformation amount or a rotational deformation amount of a pile cap (a portion near the pile head where an anchor bolt is embedded in the superstructure). A method of designing a pile in which a head is bonded to an upper structure via a predetermined bonding material and supports the upper structure,
The straight portion extending to one side of the bonding material is attached to an end plate provided on the head of the pile, and the straight portion extending to the other side via an L-shaped fixing degree reducing portion is the upper structure. And when the horizontal force acts on the head of the pile from the upper structure, the L-shaped fixing degree reducing portion is bent and deformed to cause the head of the pile to be embedded. Configured to rotate,
Set the specifications of the bonding material,
Evaluate the allowable bending moment M _a at the head of the pile,
The pile head rotation angle θ when the allowable bending moment M _a acts on the head of the pile, the following equation,
θ = (Δb + Δpl) / (Dp / 2 + r _s −x _no ) (1-c)
Δb: Elongation amount of anchor bolt on the tension side Δpl: Bending deformation amount of the L-shaped fixed degree reduction part Dp: Outer diameter of the pile r _s ; Arrangement radius of the anchor bolt x _no ; Calculated by distance,
Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:
K _θ = M _a / θ (2)
Calculated by
Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,
A method for designing a pile, wherein the specifications of the joint material are determined using the reduced generated bending moment _Mθ . Instead of the formula (1-c),
θ = (Δb + Δpl + Δα) / (Dp / 2 + r _s −x _no ) (1′−c)
The pile design method according to claim 5, wherein Δα is a compression deformation amount or a rotation deformation amount of a pile cap (a portion near the pile head where an anchor bolt is embedded in the superstructure). A method of designing a pile in which a head is bonded to an upper structure via a predetermined bonding material and supports the upper structure,
The joining material is composed of an end plate provided on the head of the pile, and an anchor bolt that is erected on the end plate and supported by the pile, and a horizontal force is When acting on the head of the pile from the superstructure, the end plate is configured to bend and deform out of plane and the head of the pile rotates.
Set the specifications of the bonding material,
Evaluate the allowable bending moment M _a at the head of the pile,
The pile head rotation angle θ when the allowable bending moment M _a is applied to the pile head joint, the following equation,
θ = (Δb + Δpe) / (Dp / 2 + r _s −x _no ) (1-d)
Δb: Elongation amount of anchor bolt on the tension side Δpe: Bending deformation amount of the end plate Dp: Outer diameter of the pile r _s ; Arrangement radius of the anchor bolt x _no ; Calculate from the distance from the compression edge of the cross section to the neutral axis position,
Using the calculated pile head rotation angle θ, the rotational stiffness K _θ is _expressed by the following equation:
K _θ = M _a / θ (2)
Calculated by
Calculate the generated bending moment M _θ using the calculated rotational stiffness K _θ ,
A method for designing a pile, wherein the specifications of the joint material are determined using the reduced generated bending moment _Mθ . Instead of the formula (1-d),
θ = (Δb + Δpe + Δα) / (Dp / 2 + r _s −x _no ) (1′−d)
The pile design method according to claim 7, wherein Δα is a compression deformation amount or a rotation deformation amount of a pile cap (a portion near the pile head where an anchor bolt is embedded in the superstructure).

Images