JP3968537B2 - Pull-out prevention structure for concrete compression materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pull-out prevention structure for concrete-based compression materials such as RC piles and SRC piles.
[0002]
[Prior art]
There are two types of pile foundations: support pile type and friction pile type. The former supports the weight of the structure by constructing the superstructure on the pile driven to the support layer when there is a good quality support layer. The latter is a basic type in which the upper structure is supported by the frictional force with the surrounding ground when there is no good quality support layer.
[0003]
The main purpose of these piles is to support the vertical load of the superstructure using the ground and the support layer as a reaction force, and the compressive strength characteristics are a major indicator. A large shearing force and bending moment act on the pile head, and depending on the proportion of the superstructure, the superstructure may lock, and a large pulling force may act on the pile at the end of the superstructure. Therefore, when designing piles, it is necessary to fully consider not only the vertical load of the superstructure, but also such an earthquake load.
[0004]
[Problems to be solved by the invention]
However, when the superstructure encounters an extremely large earthquake, an excessive pulling force acts on the pile, and the pile or the foundation slab to which the pile is joined may crack and cause tensile failure.
[0005]
In addition, bending or shear failure may occur due to a decrease in bending strength or shear strength under the action of pulling force, and the function of supporting the original vertical load of the pile may be lost.
[0006]
The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a concrete-based compressed material pull-out preventing structure capable of preventing the pile and slab from being destroyed due to the pull-out force.
[0007]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the concrete-type compression material pull-out preventing structure according to the present invention has a reinforcing material protruding from the concrete-type compression material and the reinforcement material embedded therein, as described in claim 1. A damping member that attenuates the pulling operation when the reinforcing material is pulled out from the slab, and a predetermined fixing material embedded in the slab. The reinforcing member is disposed in a gap with the reinforcing member inserted in the insertion recess formed in the fixing member, the reinforcing member is a reinforcing bar, the fixing member is a fixing sleeve, and the damping member is a high damping rubber. A gap between a reinforcing bar and the fixing sleeve is filled, or the damping member is wound around the reinforcing bar as a damping sheet, and the fixing sleeve is covered thereon.
[0008]
Further, according to the present invention, the structure for preventing pulling out of the concrete compression material is a slab in which the reinforcing material protruding from the concrete compression material and the reinforcement material are embedded and the concrete compression material are joined. A damping member that attenuates the pulling operation when the reinforcing material is pulled out from the slab is interposed between the predetermined fixing material embedded in the slab and the fixing material. A cylindrical damping member that is disposed in a gap with the reinforcing member inserted in the insertion recess formed on the reinforcing bar, the reinforcing member is a reinforcing bar, the damping member is covered with the reinforcing bar, and is fixed to the reinforcing bar, and the fixing member Is a fixing sleeve that covers the damping member, and the damping member is configured such that its outer peripheral surface slides on the inner surface of the fixing sleeve.
[0009]
In addition, as described in claim 3, the pull-out preventing structure for a concrete compression material according to the present invention includes a reinforcing material protruding from the concrete compression material and a slab in which the reinforcement material is embedded and the concrete compression material is joined. In between, a damping member that attenuates the pulling operation when the reinforcing material is pulled out from the slab is interposed, and the reinforcing material is a screw rebar, and the whole is formed in a substantially cylindrical shape in the slab. The fixing sleeve is embedded, and the fixing sleeve is used as the damping member by forming irregularities to be screwed into the screw reinforcing bars on the inner surface of the insertion recess of the fixing sleeve and forming the irregularities with a hysteresis damping material. It is what you do.
[0010]
Further, according to the present invention, the concrete-type compression material pull-out preventing structure is a slab in which the reinforcement material protruding from the concrete-type compression material is embedded and the concrete-type compression material is joined. A damping member that attenuates the pulling operation when the reinforcing material is pulled out from the slab, the reinforcing material is a reinforcing bar, and the damping member is a sheet-like high damping rubber that is wound around the reinforcing bar. It is a thing.
[0012]
In the concrete-based compressed material pull-out preventing structure according to the present invention, when a pulling force acts on the concrete-based compressed material from the slab to which the compressed material is joined, the reinforcing material protruding from the concrete-based compressed material and the reinforcement A tensile force is generated between the slab in which the material is embedded, and a damping member is interposed between the reinforcing material and the slab to attenuate the pulling operation when the reinforcing material is pulled out from the slab. The kinetic energy related to the drawing operation is a structure in which the drawing operation is quickly attenuated by energy absorption by the damping member, and the concrete compression material and the slab are not rigidly fixed, and the above-described drawing operation is allowed. Therefore, the concrete compression material and slab do not generate excessive tensile stress, resulting in their tensile failure and excessive pulling force. Bending by lowering Urn bending strength and shear strength fracture and shear fracture is prevented.
[0013]
The concrete compression material mainly corresponds to piles, but also includes pillars such as underground floors. The slab mainly corresponds to the basic slab, but also includes the underground slab. Reinforcing materials include steel bars as well as reinforcing bars.
[0014]
The damping member may be embedded in the slab as it is, but a predetermined fixing material is embedded in the slab and the reinforcing material is inserted into an insertion recess formed in the fixing material, and the reinforcing member is If the damping member is disposed in the gap between the material and the insertion recess, there is no possibility that the fresh concrete will adversely affect the damping member during slab construction.
[0015]
The structure of the damping member is arbitrary. For example, the gap between the reinforcing material and the slab or the fixing material is filled with granular or powdery material, and frictional heat due to mutual contact of these granular or powdery material is reduced. Cylindrical damping member that can be used or can be used by filling the reinforcing bar with the reinforcing member and the damping member is covered with the reinforcing bar. If the fixing member is a fixing sleeve that covers the damping member, and the damping member is configured such that its outer peripheral surface slides on the inner surface of the fixing sleeve, the kinetic energy associated with the pulling operation is attenuated. The frictional heat between the member and the fixing sleeve is reliably converted, and the drawing operation is quickly attenuated. As the damping member, for example, a friction material used in an automobile brake, for example, a sintered alloy pad obtained by sintering metal powder can be used.
[0016]
The dampening member can be configured to damp the pulling action by its hysteresis dampening. In this case, the kinetic energy related to the drawing operation is absorbed by the hysteresis attenuation of the damping member itself, and the drawing operation is quickly attenuated. As such a damping member, for example, it is conceivable to inject and solidify a high damping rubber or a highly damping resin.
[0017]
On the other hand, a fixing member and an attenuation member may be used in combination instead of separately providing an attenuation member. That is, the reinforcing material is a screw rebar, and a fixing sleeve formed in a substantially cylindrical shape is embedded in the slab, and unevenness for screwing into the screw rebar is formed on the inner surface of the insertion recess of the fixing sleeve. If the fixing sleeve is also used as the damping member by forming and forming the irregularities with a hysteresis damping material such as ultra-soft steel, the kinetic energy related to the drawing operation is changed to the hysteresis energy by the hysteresis damping material. It is absorbed and the extraction operation is quickly attenuated. The material of the hysteresis damping material is arbitrary, but it is conceivable to use, for example, extremely mild steel.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a concrete-based compressed material pull-out preventing structure according to the present invention will be described below 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.
[0019]
(First embodiment)
FIG. 1 is a view showing a pull-out preventing structure for a concrete-based compression material according to the first embodiment. As can be seen from the drawing, the pull-out prevention structure of this embodiment embeds a fixing sleeve 3 as a fixing material in an RC foundation slab 2 as a slab to which an RC pile 1 as a concrete compression material is joined. High attenuation as an attenuation member that inserts the reinforcing bar 5 protruding from the RC pile 1 into the insertion recess 4 formed in the fixing sleeve and attenuates the pulling operation by hysteresis damping when the reinforcing bar is pulled out from the insertion recess 4. Rubber 6 is filled in the gap between the reinforcing bar 5 and the fixing sleeve 3.
[0020]
The fixing sleeve 3 is formed in a substantially cylindrical shape as a whole, and is provided with irregularities 7 on its outer peripheral surface so as to ensure adhesion strength with the RC foundation slab 2. The fixing sleeve 3 can be formed of, for example, fiber reinforced plastic.
[0021]
The high damping rubber 6 is preferably configured by filling a gap between the reinforcing bar 5 and the fixing sleeve 3. The reinforcing bar 5 is a deformed reinforcing bar so that a sufficiently large frictional force is caused between the high damping rubber 6 and the reinforcing bar 5.
[0022]
In order to construct the pull-out prevention structure for the concrete compression material of the present embodiment, first, RC pile 1 is cast on site or a ready-made one is driven, and then the top end of the RC pile as shown in FIG. The main body 3b of the fixing sleeve 3 is fitted into the reinforcing bar 5 that protrudes upward. At this time, the center of the main body 3b is aligned with the center of the reinforcing bar 5 so that the gap between the inner surface of the insertion recess 4 of the main body 3b and the reinforcing bar 5 has substantially the same size on the entire circumference.
[0023]
Next, high damping rubber 6 is injected into the gap between the inner surface of the insertion recess 4 and the reinforcing bar 5 as shown by the arrow in the figure, and then the lid 3a of the fixing sleeve 3 is screwed into the main body 3b and fixed. In addition, the main body 3b of the fixing sleeve 3 can be manufactured to be long, and the main body 3b can be cut in the field according to the protruding length of the reinforcing bar 5.
[0024]
When the installation of the fixing sleeve 3 and the injection of the high-damping rubber 6 are completed, after performing the formwork, the concrete is placed on the RC foundation slab 2 to embed the fixing sleeve 3 in the slab. In addition, the edge is cut off between the top end of RC pile 1 and the bottom face of RC foundation slab 2 so that a tensile force may not be transmitted.
[0025]
In the concrete-based compressed material pull-out prevention structure according to the present embodiment, as shown in FIG. 3, the upper structure 11 is locked upward from the RC foundation slab 2 to the RC pile 1 as indicated by the arrow in FIG. When a pulling force is applied, a tensile force is generated between the reinforcing bar 5 protruding from the RC pile 1 and the fixing sleeve 3 on the RC foundation slab 2 side where the reinforcing bar is inserted, but there is a gap between the reinforcing bar 5 and the fixing sleeve 3. Is filled with the high-attenuation rubber 6 for attenuating the above-described extraction operation, so that the kinetic energy related to the extraction operation is absorbed as hysteresis attenuation by the high-attenuation rubber, and the extraction operation is quickly attenuated. Moreover, since the RC pile 1 and the RC foundation slab 2 are not rigidly fixed and the above-described drawing operation is allowed, the RC pile 1 and the RC foundation slab 2 have excessive tensile stress. Does not occur.
[0026]
As described above, according to the concrete-based compressed material pull-out preventing structure according to the present embodiment, when a pulling force acts on the RC pile 1 from the RC foundation slab 2 due to the earthquake rocking of the upper structure 11, the pull-out is performed. The kinetic energy related to the operation is attenuated by the high damping rubber 6, and as a result, the locking of the upper structure 11 can also be quickly attenuated. In addition, excessive tensile stress is not generated in the RC pile 1 or the RC foundation slab 2, and bending failure and shear failure due to reduction in bending strength and shear strength due to their tensile failure and excessive pulling force are prevented in advance. Is possible.
[0027]
In the present embodiment, the high damping rubber 6 is used as the damping member, but instead of this, a resin having a high damping property may be injected.
[0028]
Further, in the present embodiment, the high damping rubber 6 is configured to be injected and solidified, but instead, a damping sheet formed of high damping rubber or the like is wound around the reinforcing bar 5 and the fixing sleeve 3 is covered thereon. It may be.
[0029]
In the present embodiment, the RC pile is assumed as a premise, and the reinforcing bar protruding from the end of the material is inserted into the insertion recess 4 of the fixing sleeve 3. However, the concrete compression material is not limited to the RC pile, for example, SRC. If it is a pile, you may make it cover a fixing material on the steel frame which protrudes from this pile.
[0030]
In the present embodiment, the hysteresis damping material is used as the damping member, but instead, a viscous damping type or friction damping type damping member may be used. FIG. 4 shows an example in which a friction damping type damping member 13 is used. In such a modification, first, the cylindrical damping member 13 is placed on the reinforcing bar 5 and fixed to the reinforcing bar by welding or the like. Next, the fixing sleeve 3 is placed on the damping member 13, and the slab 2 is constructed in the same manner as described above, and the fixing sleeve is embedded in the slab 2.
[0031]
In this way, when a pulling force is applied from the RC foundation slab 2 to the RC pile 1 by the rocking of the upper structure 11 during an earthquake, the kinetic energy related to the pulling operation is caused, for example, by attaching metal powder of the damping member 13. It is converted into frictional heat accompanying sliding between the outer peripheral friction surface 14 and the inner surface of the insertion recess 4 of the fixing sleeve 3, and as a result, the locking of the upper structure 11 can also be quickly damped.
[0032]
Further, in the present embodiment, the high damping rubber 6 that is a damping member is filled between the fixing sleeve 3 and the reinforcing bar 5. However, such a fixing sleeve 3 is not always necessary, and in some cases, as shown in FIG. As shown, a sheet-like high-damping rubber 12 may be wound around the reinforcing bar 5 and the RC foundation slab 2 may be constructed in this state.
[0033]
(Second Embodiment)
Next, a second embodiment will be described. Note that components that are substantially the same as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0034]
FIG. 6 is a diagram showing a pull-out prevention structure for a concrete-based compression material according to the second embodiment. As can be seen from FIG. 5A, the pull-out prevention structure of this embodiment embeds a fixing sleeve 21 as a fixing material in an RC foundation slab 2 as a slab to which an RC pile 1 as a concrete compression material is joined. Then, the threaded reinforcing bar 22 protruding from the RC pile 1 is engaged with the fixing sleeve.
[0035]
The fixing sleeve 21 is formed in a substantially cylindrical shape as a whole, and the inner surface of the insertion recess 24 is formed with irregularities 25 that engage with the irregularities 23 of the screw rebar as shown in FIG. . And the unevenness | corrugation 25 is formed with the hysteresis damping material, such as a very mild steel. Further, the fixing sleeve 21 is configured so as to ensure the adhesion strength with the RC foundation slab 2 by providing irregularities 7 on the outer peripheral surface thereof.
[0036]
In order to construct the pull-out prevention structure for the concrete compression material according to the present embodiment, first, the RC pile 1 is cast in the field or after being ready-made, and then the screw protruding upward from the top end of the RC pile. The fixing sleeve 21 is screwed and fixed to the reinforcing bar 22.
[0037]
When the installation of the fixing sleeve 21 is completed, after performing the formwork, the concrete is placed on the RC foundation slab 2 to embed the fixing sleeve 21 in the slab.
[0038]
In the concrete-based compressed material pull-out preventing structure according to the present embodiment, the RC foundation slab 2 to the RC pile 1 are locked by the seismic locking of the upper structure 11 in the same manner as in the first embodiment described with reference to FIG. When an upward pulling force as shown by an arrow is applied, a tensile force is generated between the screw reinforcing bar 22 protruding from the RC pile 1 and the fixing sleeve 21 on the RC foundation slab 2 side to which the reinforcing bar is engaged. Since the unevenness 25 formed on the inner surface of the insertion recess 24 of the fixing sleeve 21 is formed of a hysteresis damping material such as ultra-soft steel, the kinetic energy related to the drawing operation is converted into the hysteresis energy accompanying the deformation of the unevenness 25. Pulling out quickly. Moreover, since the RC pile 1 and the RC foundation slab 2 are not rigidly fixed and the above-described drawing operation is allowed, the RC pile 1 and the RC foundation slab 2 have excessive tensile stress. Does not occur.
[0039]
As described above, according to the concrete-based compressed material pull-out preventing structure according to the present embodiment, when a pulling force acts on the RC pile 1 from the RC foundation slab 2 due to the earthquake rocking of the upper structure 11, the pull-out is performed. The kinetic energy related to the operation is absorbed by the deformation of the projections and depressions 25 of the insertion recess 24 formed of a hysteresis damping material, and as a result, the locking of the upper structure 11 can be quickly attenuated. In addition, excessive tensile stress is not generated in the RC pile 1 or the RC foundation slab 2, and it is possible to prevent the tensile failure in advance.
[0040]
Further, according to the present embodiment, it is possible to reduce the number of members by an amount that does not require an attenuation member, as compared with the first embodiment.
[0041]
In the present embodiment, the unevenness 25 formed on the inner surface of the insertion recess 24 of the fixing sleeve 21 is formed of a hysteresis damping material, but instead of or in addition to this, the unevenness 23 of the screw rebar 22 is formed of a hysteresis damping material. You may do it.
[0042]
Although not particularly mentioned in the first and second embodiments, it may be used in combination with a pulling resistance member such as an anchor.
[0043]
【The invention's effect】
As described above, according to the concrete-based compression preventing structure for pulling out the concrete-based compression material according to the present invention, when a pulling force acts on the concrete-based compression material from the slab due to the seismic locking of the superstructure, the pulling operation is performed. It is possible to attenuate the kinetic energy according to the above with a damping member interposed between the reinforcing material and the slab, and as a result, it is possible to quickly attenuate the rocking vibration of the upper structure. Moreover, excessive tensile stress is not generated in the above-described concrete compression material or slab, and it is also possible to prevent the tensile breakage.
[0048]
[Brief description of the drawings]
1A and 1B are diagrams of a concrete-based compression material pull-out preventing structure according to a first embodiment, in which FIG. 1A is an overall side view, FIG. 1B is a side view of a fixing material partially shown in cross section, and FIG. (A) Detailed view of (a).
FIG. 2 is a diagram showing a state in which a concrete-based compression material pull-out preventing structure according to the first embodiment is being constructed.
FIG. 3 is a view for explaining the operation of the concrete-based compression material pull-out preventing structure according to the first embodiment.
FIGS. 4A and 4B are diagrams showing a structure for preventing a concrete compression material from being pulled out according to a modification of the first embodiment, wherein FIG. 4A is an overall side view, and FIG. 4B is a side view of a fixing material partially shown in cross section; (c) is a side view of the damping member partially shown in cross section, and (d) is a detailed view of (a).
FIG. 5 is a detailed view of a concrete-based compression material pull-out preventing structure according to a modification of the first embodiment.
FIGS. 6A and 6B are diagrams showing a structure for preventing a concrete compression material from being pulled out according to the second embodiment, in which FIG. 6A is an overall side view, FIG. 6B is a side view of a fixing material partially shown in section, and FIG. Detailed view of (a).
[Explanation of symbols]
1 RC pile (compressed concrete)
2 RC basic slab (slab)
3 Fixing sleeve (fixing material)
4 Insertion recess 5 Reinforcing bar (reinforcing material)
6 High damping rubber (damping member)
11 Superstructure 12 Damping member 13 Damping member 21 Fixing sleeve (fixing material)
22 Screw rebar (rebar)
24 Insertion recess 25 Concavity and convexity (engagement part)

Claims (4)

  A damping member for attenuating the pulling operation when the reinforcing material is pulled out from the slab between the reinforcing material protruding from the concrete-based compressing material and the slab in which the reinforcing material is embedded and the concrete-based compressing material is joined. The damping member is disposed in a gap between a predetermined fixing material embedded in the slab and the reinforcing material inserted in an insertion recess formed in the fixing material, and the reinforcing material is Reinforcing bar, the fixing material as a fixing sleeve, and the damping member as a high damping rubber is filled in the gap between the reinforcing bar and the fixing sleeve, or the damping member is wound around the reinforcing bar as a damping sheet, and the fixing from above A concrete-type compression material pull-out prevention structure characterized by covering with a sleeve.   A damping member for attenuating the pulling operation when the reinforcing material is pulled out from the slab between the reinforcing material protruding from the concrete-based compressing material and the slab in which the reinforcing material is embedded and the concrete-based compressing material is joined. The damping member is disposed in a gap between a predetermined fixing material embedded in the slab and the reinforcing material inserted in an insertion recess formed in the fixing material, and the reinforcing material is A reinforcing bar, a cylindrical damping member that covers the reinforcing bar with the damping member fixed to the reinforcing bar, a fixing sleeve that covers the fixing member with the fixing material, and an outer peripheral surface of the damping member that fixes the fixing member A structure for preventing pulling out of a concrete compression material, characterized by being configured to slide on the inner surface of a sleeve.   A damping member for attenuating the pulling operation when the reinforcing material is pulled out from the slab between the reinforcing material protruding from the concrete-based compressing material and the slab in which the reinforcing material is embedded and the concrete-based compressing material is joined. The reinforcing member is a screw rebar, and a fixing sleeve formed entirely in a cylindrical shape is embedded in the slab, and the screw rebar is screwed into the inner surface of the insertion recess of the fixing sleeve. A structure for preventing pulling out of a concrete-based compression material, wherein the fixing sleeve is also used as the damping member by forming irregularities and forming the irregularities with a hysteresis damping material.   A damping member for attenuating the pulling operation when the reinforcing material is pulled out from the slab between the reinforcing material protruding from the concrete-based compressing material and the slab in which the reinforcing material is embedded and the concrete-based compressing material is joined. A structure for preventing pulling out of a concrete-based compression material, characterized in that the reinforcing material is a reinforcing bar and the damping member is a sheet-like high-damping rubber wound around the reinforcing bar.

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