JP3936621B2 - Play-filled tension type damping structure - Google Patents

Description

[0001]
[Industrial application fields]
More specifically, the present invention relates to a metal structure such as an exposed column base structure and a brace that has excellent seismic strength and has a function of absorbing seismic energy by plastic deformation. The present invention relates to a filled tension type vibration control structure.
[0002]
[Prior art and issues]
Conventionally, concrete foundation steel column base structures or braces, such as exposed column bases, are the main points for earthquake damage countermeasures and have been found to be the most concentrated place for fracture energy.
[0003]
And because of the tensile plastic deformation of the anchor bolts or brace members that are the tensile stress members generated here, play (play) occurs, and in the case of rapid repeated vibrations, play is always generated before the next tensile stress is applied. However, there is a problem that the required strength as a structure does not appear and energy absorption in the required plastic region cannot be sufficiently performed.
[0004]
Conventional exposed column bases yield anchor bolts against earthquakes and absorb earthquake energy only by plastic elongation of the anchor bolts. In this case, the restoring force characteristic (load-deformation history curve) of the exposed type column base is a slip type, but if a large amount of seismic energy is absorbed by the column base, a large interlayer deformation angle is inevitably generated in the first layer. It will be a thing.
[0005]
As a result of actual examples and experimental observations, it has been clarified that slip on the load-deformation history curve is caused by a gap generated between the base plate and the nut due to plastic elongation of the anchor bolt. These measures include the following.
[0006]
As a conventional example, there has been one in which an elastic spring is inserted between the base plate and the anchor bolt nut in order to reduce the rotational rigidity of the column base, as in the invention described in JP-A-10-299081. Further, as disclosed in Japanese Patent Application Laid-Open No. 2002-4422, a column base is supported by a square sheath-like sheath tube, but this is a low-yield member that is four energy absorbing members by separating a base plate fixed by an anchor bolt. These are means that allow the column base to freely rotate through the point steel piece. These are so-called pin column bases or semi-fixed column bases. It is clear that this does not result in effective sticking.
[0007]
That is, in the prior art, the seismic energy cannot be effectively absorbed by the plastic deformation of the anchor bolt.
[0008]
On the other hand, the conventional anchor bolts often break at the threaded part, but since the strength of the threaded part is high in the recent anchor bolts with rolled thread, the plastic elongation of the shaft part, for example, the elongation rate, does not occur. It can be expected to about 10%. In addition, it has been found that the bending deformation of the base plate is reduced, that is, it is more effective to absorb the seismic energy by increasing the deformation resistance and making it rigid compared to the elongation deformation resistance of the anchor bolt. I came.
[0009]
In the case of a brace, there is a so-called unbonded brace as disclosed in Japanese Patent Application Laid-Open No. 11-36444. This has the merit that it can resist both tensile and compressive stresses, but the brace material has a large cross section. Due to the increase in complexity and size, it is difficult to form an X-shaped brace structure, and there is a problem that it is necessary to provide a K-shaped or V-shaped brace. In addition, unbonded braces were not a countermeasure against the play.
[0010]
Therefore, as a result of earnest experiment research, the present inventor has reached the present invention that eliminates the slip phenomenon by eliminating this gap, makes the interlayer deformation angle smaller than before, and can absorb larger seismic energy.
[0011]
Initially, the effect was confirmed by retightening anchor bolts and brace nuts during the experiment as a means for filling the gap, but it is necessary to automate this when applying to actual buildings, and further experiments As a result of the research, the present invention called a play-filling type damping structure having an automatic filling mechanism as in the present invention has been completed.
[0012]
In other words, as a result of diligent experiments and researches, the present inventor has devised and introduced an automatic space filling mechanism to effectively utilize only the tensile resistance force, and the seismic energy can be obtained only by tensile deformation in the plastic region of the anchor bolt or brace. I was able to absorb it. Also, in the conventional example, without using an unbonded brace that is necessary for countermeasures against buckling due to compressive stress, buckling does not occur on the compression side, and it is possible to obtain a brace that can sufficiently withstand tensile stress continuously. became.
[0013]
OBJECT OF THE INVENTION
The first object of the present invention is to eliminate the adverse effect of the play caused by the previous vibration when the low frequency vibration is applied, during the subsequent vibration.
[0014]
The second object of the present invention is to increase the energy absorption capability especially for the moment of the steel fixed pedestal of the building, and also in the case of a brace, the interlayer deformation angle is reduced so that the deformation resistance can be exerted immediately without any play. It is a thing.
[0015]
The third object of the present invention is that the load-deformation history curve is a non-slip type (starting origin type) instead of the conventional slip type in the exposed type column base, and a spindle type instead of the conventional slip type in the brace as well. In other words, energy absorption can be effectively performed, and deformation prediction or strength calculation by a computer can be easily performed.
[0016]
[Structure of the invention]
According to the present invention,
When a joint is repeatedly subjected to tensile stress due to vibration such as an earthquake, the tensile stress damping structure that absorbs the seismic energy by plastic deformation of a tensile stress member made of anchor bolts or braces, the joint that occurred earlier It is equipped with an automatic filling mechanism in which the clearance between the parts is automatically filled by an insertion type wedge inserted by an elastic biasing force in a direction substantially perpendicular to the tensile stress. A gap-filled tension-type damping structure characterized in that plastic deformation of the tensile stress member is started without a gap (claim 1),
Clearance joint filling tension type vibration control structure is a base plate and the anchor bolt and nut between the junctions or X-shaped brace end plate and struts nut between the junction of the exposed type column base in civil engineering structure according The free-filling tension type damping structure according to Item 1 (Claim 2),
The free-filling tension type damping structure (claim 3) according to claim 2, wherein a tip inclination angle θ of the insertion type wedge is 15 ° ≤ θ ≤ 75 °,
Elastic body for the insertion wedge insert is a coil spring, helical spring, leaf spring, tensile clearance filling according to any one of the preceding claims 2 is one or more combinations of the rubber cushions 3 Type seismic control structure (Claim 4),
The joint of the free-filling tension type damping structure is a joint between the base plate of the exposed column base and the anchor bolt and nut in the civil engineering structure, and is a non-slip type in which the load-deformation history curve always rises at the origin. The clearance-filled tension type damping structure according to any one of 1 to 4 (Claim 5)
and
The joint of the free-filling tension type damping structure is the joint between the X-shaped brace end plate and the brace nut in the civil engineering building structure, and the load-deformation history curve of the pair of brace is the spindle type The play-filling tension type vibration control structure according to any one of claims 1 to 5 (claim 6)
Is provided.
[0017]
Hereinafter, the present invention will be described in detail using examples.
[0018]
【Example】
1 is a side view of the column base before the start of vibration, FIG. 2 is a side view of the column base after 1/2 cycle of vibration, FIG. 3 is a side view of the column base after one cycle of vibration, and FIG. FIG. 5 is a view taken along the line BB in FIG. 2, FIG. 6 is a view taken along the line CC in FIG. 3, FIG. 7 is a perspective view of the insertion wedge, and FIG. 9 is a side view of the column base when it receives a clockwise moment M, FIG. 9 is a side view of the column base when it receives an axial force N and a clockwise moment M ′, and FIG. FIG. 11 is a side view of a column base portion showing a situation where play gaps G ₂ and G ₂ are generated by plastic elongation between the left and right anchor bolt screw nuts and the base plate, FIG. 11 is a side view of the first embodiment using a one-way clutch, and FIG. Load-deformation history graph of a conventional example (no clearance filling) (when axial force N does not act), FIG. 13 is a load-deformation history graph of Example 1 (when axial force N does not act) Rough, FIG. 14 is a load-deformation history graph of a conventional example (no clearance filling) (when axial force N is applied), and FIG. 15 is a load-deformation history graph of Example 1 (when axial force N is applied). 16 is a side view of the second embodiment before the start of vibration, FIG. 17 is a side view of the second embodiment after one cycle of vibration, and FIG. 18 is a load-deformation history graph of the second embodiment.
[0019]
1-18,
1 is Example 1, 200 is Example 2, 2 is a column base, 4 is a base plate, 6 is an anchor bolt, 6A is an anchor bolt screw part, 7 is a nut, 10, 10A, and 10B are insertion-type wedges, respectively, before insertion 10K is an elongated bolt hole, 10P is an inclined wall, 10S is an inclined surface, 11 is a wedge receiver, 13 is a spring receiver, G ₁ , G ₂ , and G ₃ are Play, N is axial force, M is moment, C is compression reaction force, V is tensile reaction force, W is fillet weld, 14A is compressed coil spring, 14B is extended coil spring, 20 is concrete foundation, 30 Is a one-way bearing, 31 is a needle roller, 32 and 33 are bearing races, 32A is an inclined groove, 34 is a movable retainer, and 35 is a push-pull coil spring.
<Example 1>
First, in the column base, when a vibration is given for 1/2 cycle,
That is, when an axial force N in the column base direction and a moment M in the counterclockwise direction are applied to the column base, the column base is in a state as shown in FIG. 8, and tilts to the left with the left end of the base plate as a fulcrum. If the rigidity of the base plate 4 is high, the right anchor bolt 6 yields after a short elastic deformation, causing a tensile plastic deformation in a substantially vertical direction. The vibration energy is absorbed by the anchor bolt 6 here. Similarly, FIG. 9 shows a case where a clockwise moment M ′ is applied.
[0020]
As the material of the anchor bolt, JISG3138 rolled steel bar for building structure, SNR400A, SNR400B, SNR490B, etc. are most commonly used. A material that has a relatively small work hardening coefficient and is easy to plastically stretch is desirable. In view of economic efficiency, Zn-Al alloy or the like can be used as the superplastic material in addition to the mild steel material.
[0021]
An insertion wedge whose perspective view is shown in FIG. 7 will be described. The material is preferably made of tough cast steel.
[0022]
Next, as shown in FIG. 9, when the reverse moment M ′ acts in the opposite direction (clockwise) of the moment M, the left anchor bolt is pulled and extended with the right end portion of the base plate 4 as a fulcrum. That is, when a repeated load of one cycle or more is applied, the pair of left and right anchor bolts receive a tensile stress in the longitudinal direction, and plastic elongation occurs (see FIG. 10).
[0023]
However, since the gaps G ₁ and G ₂ are generated in the conventional example as shown in FIG. 9, the load-deformation history curves are as shown in FIG. 12 or FIG. Therefore, the vibration control effect is poor.
[0024]
In the conventional example, the case of FIG. 14 is the case where the axial force N acts, and the case of FIG. 12 is the case where the axial force N does not act.
[0025]
However since the insertion wedge present invention Example 1 closes the clearance and inserted into clearance G _2, G 2 _... 13, the load as in Figure 15 - deformation hysteresis curve origin rising bowtie (bow-tie ) And no slip occurs, so that the seismic energy is easily absorbed and the seismic control effect is increased.
[0026]
Note that the tip inclination angle (vertical angle) θ of the insertion-type wedge of the present invention is 15 ° ≦ θ ≦ 75 °, and more preferably 30 ° ≦ θ ≦ 60 °.
[0027]
The reason for the limitation will be described below.
[0028]
First, if θ does not reach 15 °, the distance in the vertical direction cannot be obtained for the horizontal movement distance of the insertion-type wedge, so that it is not practical, and the thickness of the wedge receiver becomes too small and the rigidity becomes small. If the angle exceeds 75 °, the vertical movement distance becomes too large compared to the horizontal movement distance of the insertion type wedge, and the slope friction force after the insertion type wedge is inserted becomes smaller. This is because the anchor bolt head exposed on the base plate is long and is unstable because it is unstable mechanically.
[0029]
More preferably, 30 ° ≦ θ ≦ 60 °, but the reason for this limitation is as follows.
[0030]
If θ is less than 30 °, the insertion wedge is thin as a whole, although it is within the scope of the present invention, the rigidity tends to be difficult to maintain, and it is difficult to implement the present invention with a limited base plate surface area. Further, if θ exceeds 60 °, the insertion wedge height is slightly increased even within the range of the present invention, and the anchor bolt head length is long as described above, so that it is difficult to maintain stability. . Also in the manufacturing process of the insertion type wedge, when 30 ° ≦ θ ≦ 60 °, there is an advantage that it is easy to handle.
[0031]
In addition, a helical spring, a leaf | plate spring, or a rubber cushion can also be used for the elastic body which pushes an insertion type wedge instead of a coil spring. Two or more of these may be combined. In the present invention, there is no need for a frictional force caused by a pressing force in the radial direction or the thickness direction of the specimen between the specimen surface used in the conventional specimen holder (chuck) of the tensile testing machine and the tapered wedge that squeezes in the tensile direction. Yes, for example, in the present invention, the friction surfaces of the insertion type wedge, the base plate and the wedge receiver that move in a direction substantially perpendicular to the tensile direction have a friction coefficient over a long period of time (for example, 50 years). Thus, it is desirable to perform a surface finish that is small in the wedge insertion direction and kept high in the backward direction, for example, a surface treatment such as sand blasting or galvanizing.
[0032]
The insertion type wedge is for filling the gaps G ₁ , G ₂ ... Generated in the plastic elongation of the anchor bolt, and is not forcibly press-fitted between the base plate and the wedge receiver. The urging force is sufficient to allow the insertion type wedge to be automatically inserted immediately without any gaps in the play caused by the earthquake. This also applies to the bracing embodiment 2.
[0033]
It is desirable to add a one-way clutch 30 that can move only in the insertion direction or a surface treatment having a similar tendency to some or all of these friction surfaces (see FIG. 11). That is, it is desirable that the friction coefficient of the friction surface between the insertion-type wedge and the base plate or the wedge receiver is at least μ _in <μ _out, where μ _in is the friction coefficient in the wedge insertion direction and μ _{out in} the retraction direction.
[0034]
FIG. 11 shows a cross-sectional view of an example in which a one-way clutch including a needle roller, an inclined grooved bearing race, and a movable retainer is used between the lower surface of the insertion wedge and the upper surface of the base plate.
[0035]
The needle rollers 31, 31... Are pushed deeper in the inclined groove by the movable retainer 34 connected by a push-pull coil spring that is pulled in the insertion direction, so that the needle roller 31 can move only in the insertion direction, and the needle roller in the reverse direction. It stops when a strong pressure is applied between the top and bottom. This type of one-way clutch is disclosed in JP-A-10-61743.
[0036]
<Example 2>
Example 2 is an example in which the present invention is applied to tensile deformation of a brace.
[0037]
FIG. 16 is a side view of the X-shaped brace before being subjected to repeated loading, and FIG. 17 is an X-shaped after being subjected to at least 1/2 cycle of repeated loading that causes plastic stretching to occur in the X-shaped bracing. FIG.
[0038]
1 to 18,
Furthermore 15A, 15B are bracing, 17, 18 bracket, 17A, 18A are braced attachment portion, especially 17 A is an end plate which is elements of the invention, 19 receives the coil spring, 21 a vertical frame, 22 Is a horizontal frame, and 25 is a bearing wall.
[0039]
Normally, as shown in FIG. 16, the brace is arranged in an X shape within a bearing wall 25 surrounded by a pair of vertical frame 21 and horizontal frame 22, and is surrounded by vertical frame 21 and horizontal frame 22. One block forms the bearing wall 25. When shearing forces S ₁ and S ₂ are applied to the bearing wall 25, tensile forces are applied in the order of the braces 15A and 15B, respectively, and when they yield, plastic elongation occurs and seismic energy is absorbed.
[0040]
Its other bracing 15B, since the respective clearance _G 3, _{G 3} occurring in 15A, as in the case insertion wedge 10A of Example 1, 10A are inserted into the clearance _{G 3, G} 3, Yu After the gaps G ₃ and G ₃ are filled, the strain due to the shearing force applied to the load bearing wall 25 does not slip after the earthquake cycle, and the load-deformation history curve becomes a spindle type as shown in FIG.
[0041]
【The invention's effect】
By implementing the present invention, all of the above objects can be achieved. In other words, when a low frequency vibration is applied, the adverse effect of the play caused by the previous vibration can be minimized during the subsequent vibration.
[0042]
In addition, the energy absorption capacity for the moment of the steel fixed pedestal of the building has been increased, and even in the case of braces, the deformation angle of the brace members can be immediately exerted without play by reducing the interlayer deformation angle.
[0043]
Furthermore, the load-deformation history curve is not a conventional slip type for exposed column bases, but a bow tie type (starting origin type), and a brace is also not a conventional slip type but a spindle type for effective energy absorption. As a result, it is possible to easily perform deformation prediction or strength calculation by a computer.
[0044]
In addition, the automatic gap filling mechanism including the insertion type wedge according to the present invention is simple in structure and inexpensive, but can be reliably operated, and the above-described effects can be easily obtained.
[0045]
More specifically, when the present invention is used for a brace, it is possible to obtain a brace having the following advantages.
(1) The compressive force does not act on the brace. Therefore, the design for buckling prevention is unnecessary.
(2) Since the tensile resistance starts as soon as the brace tensile force begins to act, the slip-type restoring force characteristics are not obtained. Therefore, the energy absorption capability as a brace can be maximized.
(3) Since only the tensile force is resisted, the restoring force characteristic as a bracing is the simplest fully elastic-plastic model. The striation can be predicted only by the cross-sectional area and the yield stress level. Furthermore, if the end joint is designed to have a yield strength, the critical interlayer deformation angle can be easily calculated from the strut length and the critical strain.
(4) It is possible to easily measure how much the struts have undergone plastic elongation after the earthquake and to investigate the remaining life (elongation ability) after that.
(5) Since the present invention apparatus can be attached to the existing brace by slightly improving the end joint portion, it can be easily replaced with a brace having improved restoring force characteristics at the time of seismic retrofit.
[Brief description of the drawings]
FIG. 1 is a side view of a column base before starting vibration.
FIG. 2 is a side view of a column base after a half cycle of vibration.
FIG. 3 is a side view of a column base after one cycle of vibration.
4 is an AA arrow view of FIG. 1;
FIG. 5 is a view taken along arrow BB in FIG. 2;
6 is a view taken along the line CC in FIG. 3;
FIG. 7 is a perspective view of an insertion-type wedge.
FIG. 8 is a side view of a column base when it receives an axial force N and a counterclockwise moment M.
FIG. 9 is a side view of the column base when it receives an axial force N and a clockwise moment M ′.
FIG. 10 is a side view of the column base part showing a situation in which clearances G ₂ and G ₂ are generated by plastic elongation between the right and left anchor bolt screw nuts and the base plate after restoration.
FIG. 11 is a side view of the first embodiment using a one-way clutch.
FIG. 12 is a load-deformation history graph of a conventional example (no clearance filling) (when axial force N does not act).
13 is a load-deformation history graph of Example 1 (when axial force N does not act). FIG.
FIG. 14 is a load-deformation history graph of a conventional example (no clearance filling) (when axial force N is applied).
15 is a load-deformation history graph of Example 1 (when axial force N is applied). FIG.
FIG. 16 is a side view of Example 2 before the start of vibration.
FIG. 17 is a side view of Example 2 after one vibration cycle.
18 is a load-deformation history graph of Example 2. FIG.
[Explanation of symbols]
1 Example 1
200 Example 2
2 Column base part 4 Base plate 6 Anchor bolt 6A Anchor bolt screw part 7 Nut 10 Insertion type wedge 10A Insertion type wedge 10B before insertion Insertion type wedge 10K after insertion Bolt long hole 10P Inclined wall 10S Inclined surface 11 Wedge receiver 13 Spring receiver G ₁ , G ₂ , G ₃ clearance N axial force M moment C compression reaction force V tensile reaction force W fillet weld 14A compressed coil spring 14B extended coil spring 20 concrete foundation 30 unidirectional bearing 31 needle rollers 32, 33 bearing Race 32A Inclined groove 34 Movable retainer 35 Push-pull coil springs 15A, 15B Brace 17, 18 Brackets 17A, 18A Brace mounting portion 19 Coil spring receiver 21 Vertical frame 22 Horizontal frame 25 Bearing wall

Claims (6)

  When a joint is repeatedly subjected to tensile stress due to vibrations such as an earthquake, the joint that has occurred in the tensile type damping structure that absorbs the seismic energy by plastic deformation of the tensile stress member consisting of anchor bolts or braces It is equipped with an automatic filling mechanism in which the clearance between the parts is automatically filled by an insertion type wedge inserted by an elastic body biasing force in a direction substantially perpendicular to the tensile stress, and when the next tensile stress is applied, A clearance-filled tension-type damping structure characterized in that plastic deformation of the tensile stress member is started without a gap.   The joint of the free-filling tension type damping structure is a joint between the exposed column base plate and the anchor bolt nut or the joint between the X-shaped brace end plate and the brace nut in the civil engineering structure. Item 2. A free-filling tension type vibration control structure according to item 1.   3. The play-filling tension type damping structure according to claim 2, wherein the tip-type inclination angle θ of the insertion type wedge is 15 ° ≦ θ ≦ 75 °. Elastic body for the insertion wedge insert is a coil spring, helical spring, leaf spring, tensile clearance filling according to any one of the preceding claims 2 is one or more combinations of the rubber cushions 3 Type seismic control structure. The joint of the free-filling tension type damping structure is a joint between the base plate of the exposed column base and the anchor bolt and nut in the civil engineering structure, and is a non-slip type in which the load-deformation history curve always rises at the origin. 5. The play-filling tension type vibration control structure according to any one of 1 to 4. The joint of the free-filling tension type damping structure is the joint between the X-shaped brace end plate and the brace nut in the civil engineering building structure, and the load-deformation history curve of the pair of brace is the spindle type The play-filling tension type vibration control structure according to any one of claims 1 to 5.

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