JP5135035B2 - Fixing structure between base plate and anchor bolt in exposed column base - Google Patents

Description

  The present invention relates to an improved technique related to a fixing structure of a base plate and an anchor bolt in an exposed column base having a vibration damping function for absorbing vibration energy by an anchor bolt.

Recently, many attempts have been made to improve the vibration damping function of the exposed column base by improving the ability to absorb vibration energy acting on the column base during an earthquake. For example, an anchor bolt is inserted into the periphery of the base plate fixed to the lower end portion of the column member and is fastened and fixed with a nut from above and below, and a gap is provided between the base plate and the foundation concrete, and the anchor bolt in the gap portion is provided. That absorbs the bending moment acting on the column base due to the expansion and contraction of the steel (Patent Document 1) and the anchor bolt is embedded in the non-bonded state with respect to the foundation concrete, and the vibration energy is absorbed by the anchor bolt. Those with increased capacity (Patent Document 2), and further restrained so that buckling does not occur by externally fitting a sleeve to an anchor bolt located in the gap formed above the foundation concrete Etc. are known (Patent Document 3).
JP-A-4-31658 JP 2006-233444 A JP-A-9-13388

By the way, in the prior art employing the above-described vibration control structure, the base plate and the anchor bolt inserted through the insertion hole formed in the periphery thereof can be firmly and stably tightened and fixed using the upper and lower nuts. However, it is an extremely important precondition for accurately realizing the original vibration control action. The base plate and anchor bolts are fixed by constraining the nut against rotation with respect to the base plate by providing a recess larger than the outer shape of the nut in the nut mounting portion on the upper surface of the base plate and filling and solidifying the adhesive. A conventional technique is known in which an adhesive is filled and solidified between a bolt insertion hole formed in a base plate and an anchor bolt, while being fixed in the above state (Patent Document 4). However, in the case of this conventional technique, a technical means is adopted in which a depression is provided on the surface of the base plate and the adhesive is filled and solidified in the depression. Since it flows down from the depression before solidification, it has been difficult to apply as a means for preventing loosening of the nut on the lower surface side. Therefore, in the case where the vibration energy is absorbed not only in the tension direction but also in the compression direction with respect to the anchor bolt, the problem of loosening of the nut on the lower surface side of the base plate remains. In particular, in the case of a configuration in which a gap is provided between the base plate and the foundation concrete and vibration energy is absorbed by deformation in both directions of the anchor bolt in the gap, the nut on the lower surface side of the base plate is loosened. It was difficult to eliminate the problem of shakiness in the compression direction.
JP-A-9-1000082

  In view of the above-described conventional technical situation, the present invention can be effectively applied to an exposed column base structure in which vibration energy in the compression direction as well as the tensile direction is absorbed by the anchor bolt. It is an object of the present invention to provide a structure for fixing a base plate and an anchor bolt in an exposed column base that is easy to use and can accurately and stably prevent loosening of a nut against vibrations.

In order to solve the above-mentioned problem, in the invention of claim 1, the base plate fixed to the lower end portion of the column member is fixed by a plurality of anchor bolts fixed to the foundation concrete, and these anchor bolts are used in the tensile direction and the compression direction. In the exposed column base structure configured to absorb the bidirectional vibration energy and exhibit a damping function, the base plate is connected to the anchor bolts respectively inserted into the plurality of bolt insertion holes provided in the peripheral portion of the base plate. From above and below, a nut larger than the bolt insertion hole formed on the washer is sandwiched in a state where it is open to the contact side with the base plate, and then a nut is screwed, and the base plate is fastened and fixed from above and below by the nut. And inserting the bolts connecting the recesses formed in the upper and lower washers and the recesses. And filled with grout comprising an inflatable against the gap between the anchor bolt, the upper and lower washer, the base plate, and by inflating solidified in an enclosed gap by the anchor bolt, the base plate and anchor bolts Adopted the technical means to fix firmly. The washer may be formed integrally with the nut (Claim 2), or the present invention can be applied to a form in which the base plate is fastened and fixed in a state of being separated from the upper surface of the foundation concrete ( Claim 3).

According to the present invention, as described above, a technical means is adopted in which a concave portion larger than the bolt insertion hole is formed in the washer, and the concave portion is clamped and fixed by a nut after being sandwiched in a state of being open to the contact side with the base plate. Therefore, even when applied to tightening and fixing from the lower surface side of the base plate, the open portion above the recess formed in the washer is closed by the lower surface of the base plate, so that the grout material filled inside flows down. The conventional problem is surely solved. In addition, since the technical means to expand and solidify using a grout material with expandability, a recess formed in the washer installed above and below the base plate by the expansion action in the solidification process of the grout material It is possible to accurately fill and solidify every corner with respect to the gap portion between the anchor bolt connecting the recess and the bolt insertion hole. As a result of the expansion action in the solidification process of the grout material, the grout material firmly enters the male screw portion in the gap portion formed in the anchor bolt, and the state in which the male screw portion enters is ensured by the expansion action. Since the grout material solidifies while maintaining the above-mentioned structure, the desired fixing action at the male screw portion can be realized accurately and stably. Therefore, the anchor is particularly important for securing a vibration damping function that absorbs vibration energy by the anchor bolt. It is possible to more stably reinforce the fixed state between the anchor bolt and the base plate against the tensile force and compressive force acting in the axial direction of the bolt. Moreover, the grout material is surrounded by a rigid base plate, anchor bolts, and upper and lower washers, and is expanded and solidified in a substantially sealed gap, thereby forming a high-density and high-strength grout layer . Since the grout material filled and solidified in the recesses of the upper and lower washers is integrated through the grout material filled and solidified in the gap between the anchor bolt and the bolt insertion hole, Combined with a stable contact frictional force, it is possible to accurately prevent the upper and lower nuts from loosening. Furthermore, since the grout material filled in the recess outside the bolt insertion hole provided in the washer causes a vertical expansion pressure to act on the part in the solidification process, the base plate and the washer are connected via the grout material . adhesion is enhanced, Ru effective der to prevent rattling by vertical force. As described above, according to the present invention, since the base plate and the anchor bolt can be firmly and loosely fixed from above and below the base plate by the nut, the tensile direction and the compression direction that act via the base plate in the event of an earthquake or the like are repeated. It is possible to accurately transmit the load to the anchor bolt and stably absorb the vibration energy, and to realize a good damping function.

  In the present invention, a base plate fixed to a lower end portion of a column member is fixed by a plurality of anchor bolts fixed to a foundation concrete, and vibration energy in both a tensile direction and a compression direction at the time of earthquake is obtained by the anchor bolts. Any exposed column base structure configured to absorb and exhibit a damping function can be widely applied. Not only is the base plate clamped and fixed in a state of being separated from the top surface of the foundation concrete, but also a heat insulating material having a compressibility that does not substantially impose a compressive force in the gap between the base plate and the foundation concrete. The base plate is placed on the foundation concrete using anchor bolts embedded in the non-adhesive state with respect to the foundation concrete, and the sleeve is fitted by externally fitting a sleeve to the anchor bolt. The present invention can also be applied to a configuration that is constrained so that bending does not occur. Further, the washer may be configured separately from the nut or may be configured integrally. Incidentally, when the washer is configured separately from the nut, the washer and the nut may be fixed by welding or the like after the completion of tightening. The concave portion formed in the washer is not limited to a perfect circle, but the specific shape is not limited as long as it is larger than the bolt insertion hole formed in the base plate. It is practical. Of the washers applied to the top and bottom, at least the washer installed above is formed with an inlet for a grout material leading to the internal recess. It is also effective to form a grout injection port for the washer applied to both the upper and lower sides, and to provide a plug or the like as a closing means for the injection port for the washer installed below. In addition, as a grout material, the inorganic thing which has an expansibility is suitable, and after passing through expansion | swelling and shrinkage | contraction in an open state, it finally solidifies in an expanded state.

  FIG. 1 is a cross-sectional view of an essential part showing an embodiment of the present invention, and FIG. 2 is a partially enlarged cross-sectional view thereof. In the figure, reference numeral 1 denotes a base plate, which is fixed to the lower end portion of the column member 2 by welding or the like. The base plate 1 is fixed by a plurality of anchor bolts 4 fixed to the foundation concrete 3. In the present embodiment, the case where the base plate 1 is installed in a state of being separated from the upper surface of the foundation concrete 3 is exemplified, but a mode of installation in a state of being placed on the upper surface of the foundation concrete 3 using anchor bolts that are not bonded is also possible. Is possible. The same number of bolt insertion holes 5 corresponding to the anchor bolts 4 are formed in the periphery of the base plate 1, and the heads of the anchor bolts 4 are inserted into the respective bolt insertion holes 5 as shown in the figure. The nuts 8 and 9 are screwed together after the washers 6 and 7 having recesses larger than the bolt insertion holes 5 are sandwiched from above and below in a state where the recesses are opened to the contact side with the base plate 1. The base plate 1 is fastened and fixed from above and below by the nuts 8 and 9. In the figure, reference numeral 10 denotes a lock nut for preventing looseness. In the figure, M is a bending moment acting on the column base, Fa is a compressive force acting on the anchor bolt 4, and Fb is a tensile force acting on other anchor bolts. When the bending moment M acts on the column base, a repeated load composed of the compression force Fa and the tensile force Fb acts on the anchor bolt 4 according to the direction of the bending moment M.

  Next, the washer 6, 7 which is a characteristic part of the present invention will be described. 3 to 5 show the washer 6. FIG. 3 is a sectional view, FIG. 4 is a plan view, and FIG. 5 is a bottom view. 6 and 7 show the washer 7. FIG. 6 is a sectional view and FIG. 7 is a bottom view. The washer 6 is a washer that is applied to the upper surface side of the base plate 1. As shown in FIGS. 3 to 5, the concave portion 11 made of a flat circular counterbore is formed on one surface, and the concave portion An inlet 12 for a grout material communicating with 11 is formed. Further, the washer 7 is a washer applied to the lower surface side of the base plate 1, and as shown in FIGS. 6 and 7, a recess 13 made of a flat counterbore similar to the recess 11 is formed on one surface. Is formed. Here, the most important point is that the size of the recess 11 formed on the washer 6 and the recess 13 formed on the washer 7 are set larger than the bolt insertion holes 5 formed on the base plate 1. And the upper and lower surfaces of the base plate 1 are configured so that the grout material filled in the recesses 11 and 13 can be solidified integrally via the grout material filled in the gap between the anchor bolt 4 and the bolt insertion hole 5. In order to prevent the loosening of the upper and lower nuts accurately and stably, it is possible to stably secure a strong frictional force by contacting them in a wide range. In the present embodiment, for the washer 7 applied to the lower surface side of the base plate 1, the case where no grout injection port communicating with the recess 13 is provided is illustrated.

  Thus, in the construction of the present embodiment, as shown in FIGS. 1 and 2, firstly, a nut 9 below the anchor bolt 4 embedded in the foundation concrete 3 and fixed in an appropriate form. And the lower washer 7 is installed on the upper part thereof in a state where the recess 13 is directed upward and is opened to the contact side with the base plate 1. Next, while inserting each anchor bolt 4 into the corresponding bolt insertion hole 5, the base plate 1 is placed on the top of the washer 7, and further on the head of each anchor bolt 4 protruding above the base plate 1. On the other hand, the upper washer 6 is installed in a state where the concave portion 11 is directed downward and is opened to the contact side with the base plate 1, and the upper nut 8 and the locking nut 9 are loosely screwed onto the upper portion thereof. Next, the base plate 1 is fastened and fixed from above and below by the lower nut 9 and the upper nut 8, and the base plate 1 is installed in a state spaced apart from the upper surface of the foundation concrete 3 by a predetermined amount. Thereafter, a grout material having expansibility mixed with an appropriate foaming material or the like is filled from the inlet 12 communicating with the recess 11 formed in the upper washer 6. Thus, the expandable grout material injected from the injection port 12 flows into the recess 11 formed in the upper washer 6 and further into the gap between the anchor bolt 4 and the bolt insertion hole 5 and the lower washer 7. It flows sequentially into the formed recesses 13 and fills them. And when solidification of the grout material with which each of those parts was started, the foaming material etc. which were mixed in the grout material in the process of the solidification will expand, and an expansion pressure will be exerted on the surrounding grout material. Also, by the action of the expansion pressure, the grout material is filled evenly and accurately into the recesses 11 and 13 formed in the upper and lower washers 6 and 7 and every corner of the gap portion between the anchor bolt 4 and the bolt insertion hole 5. And will solidify in that state. As a result, the grout material filled and solidified in the recesses 11 and 13 accurately contacts the upper and lower surfaces of the base plate 1 in a wide area, and a stable and strong friction state is obtained. Moreover, since the grout material filled and solidified in the recesses 11 and 13 is solidified integrally with the grout material filled and solidified in the gap portion between the anchor bolt 4 and the bolt insertion hole 5, the nuts are combined with each other. It is possible to accurately and stably prevent the slack of the slack.

It is principal part sectional drawing which showed one Example of this invention. It is a partial expanded sectional view of the Example. It is sectional drawing which showed the washer used for the Example. It is the top view which showed the washer. It is the bottom view which showed the washer. It is sectional drawing which showed the other washer used for the said Example. It is the bottom view which showed the washer.

Explanation of symbols

  1: base plate, 2: pillar material, 3: basic concrete, 4: anchor bolt, 5: bolt insertion hole, 6, 7: washer, 8, 9: nut, 10: lock nut, 11: recess, 12: injection port , 13: recess

Claims (3)

The base plate fixed to the lower end of the column is fixed by multiple anchor bolts fixed to the foundation concrete, and the vibration energy is absorbed by absorbing vibration energy in both the tensile and compression directions. In the exposed column base structure configured to perform, the bolt insertion in which a washer is formed in the washer from above and below the base plate with respect to anchor bolts respectively inserted into a plurality of bolt insertion holes provided in a peripheral portion of the base plate A recess larger than the hole is sandwiched between the base plate and the base plate, and a nut is screwed together. The base plate is fastened and fixed from above and below by the nut, and the recess formed in the upper and lower washers and the The expansibility of the gap between the bolt insertion hole and the anchor bolt connecting the recess Filling the obtaining grout, the upper and lower washer, the base plate, and by inflating solidified in an enclosed gap by the anchor bolt, the base plate in the exposed type column base, characterized in that to fix the base plate and anchor bolts And fixing structure with anchor bolts.   The structure for fixing the base plate and the anchor bolt in the exposed column base according to claim 1, wherein the washer is formed integrally with the nut.   The structure for fixing the base plate and the anchor bolt in the exposed column base according to claim 1 or 2, wherein the base plate is fastened and fixed in a state of being separated from the upper surface of the foundation concrete.

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