JPWO2015037094A1 - Column base structure - Google Patents

Abstract

Improve the energy absorption capacity of the column base structure to prevent damage, breakage, or collapse of the building structure, and prevent the column base structure or building structure from becoming large, heavy, or expensive. Provide a column base structure that can In the column base structure 40 in which the peripheral portion of the metal joint 42 joined to the lower end portion of the column member 4 is fixed by the anchor bolt 10 protruding upward from the foundation concrete 3, and the anchor bolt 10 yields before the column member 4. The first bending moment Ma at which the anchor bolt 10 starts yielding is larger than the second bending moment Mb at which the peripheral portion of the joint metal 42 starts yielding, and 1.5 times or less of the second bending moment Mb. Was set to be.

Description

  According to the present invention, a metal joint joined to a lower end portion of a pillar member in a building structure is arranged above the foundation concrete, and is fixed to a tip end portion of an anchor bolt protruding upward from the foundation concrete. This is also related to the column base structure where the anchor bolt yields first.

  12 to 15 are views referred to for explaining the conventional column base structure 2.

  In the conventional column base structure 2, as shown in FIG. 12, a plate-shaped column base metal 6 having substantially square front and back surfaces is provided above a foundation concrete 3 via a mortar 8. This column base metal 6 is made of metal, and the lower end surface of a rectangular steel column 4 (column member) having a length in the vertical direction in the figure is joined to the upper surface 6a (surface) by welding. .

  The upper end portion of the anchor bolt 10 protruding upward from the foundation concrete 3 was inserted through the bolt insertion hole 6 b and the through hole of the washer 16 at the peripheral edge of the column base 6. The steel column 4 stands on the foundation concrete 3 via the column base metal 6 and the mortar 8 by screwing the male screw portion formed on the upper end portion of the anchor bolt 10 to the female screw portion of the nut member 12. It was installed and fixed (for example, refer patent document 1).

  Further, in the basic concrete 3, a male screw portion formed at the lower end portion of the anchor bolt 10 is screwed to a female screw portion of the nut member 14, and a fixing plate 18 is placed on the nut member 14. It was.

  In addition, as another conventional column base structure, instead of the column base metal 6, a bottom plate portion and a support base portion in which a central portion of the upper surface of the bottom plate portion protrudes upward from the peripheral edge portion thereof are supported. There was a column base structure using a column base hardware different from a flat plate shape in which the lower end surface of the steel column was joined to the upper surface of the base portion by welding (for example, see Patent Document 2).

  In another conventional column base structure according to Patent Document 2, the upper end portion of the anchor bolt protruding upward from the foundation concrete is a bolt insertion hole that penetrates the thickness direction of the peripheral portion of the bottom plate portion of the column base hardware. Insert the male screw part formed on the anchor bolt into the female screw part of the nut member, and the steel column is fixed on the foundation concrete via the column base metal and mortar. It was.

  By the way, the steel column 4 in the conventional column base structure 2 is rotated clockwise around the rotation center O of the joint portion of the steel column 4 with the column base metal 6 as shown in FIG. When a load that generates a large bending moment M for rotating the steel column 4 is applied in the direction, the bending moment M acts to lift the left end of the column base 6 in FIG. .

  On the other hand, the anchor bolt 10 fixed to the left side portion of the column base metal 6 from the rotation center O in FIG. 13 starts yielding without resisting the load that generates the bending moment M and moves upward in the figure. By extending its own length (plastically deforming), energy due to a load that generates the bending moment M is absorbed.

JP 2003-232078 A JP 2003-336266 A

  However, in the conventional column base structure 2, as shown in FIG. 14, the anchor bolt 10 that has been plastically deformed remains in an upward state in the drawing even after the load that generates the bending moment M is removed. Therefore, a large gap S remains between the lower surface of the nut member 12 and the upper surface of the washer 16.

  For this reason, when a load that generates the bending moment M is applied again, the energy absorption capacity of the conventional column base structure 2 is significantly reduced compared to when a load that generates the bending moment M is applied first. There was a problem.

  Such a problem of the conventional column base structure 2 will be described in detail with reference to FIGS. 15 shows the bending center M applied to the steel column 4 in the conventional column base structure 2 (see FIG. 13) and the rotation center O of the joint between the steel column 4 and the column base metal 6 up and down. FIG. 14 is a hysteresis diagram (history characteristic diagram) schematically showing a correspondence relationship with a rotation angle θ from a one-dot chain line (see FIG. 13) passing in a direction.

  In the conventional column base structure 2, the yield starting bending moment when the anchor bolt 10 starts yielding is the same as the yield starting bending moment when the steel column 4 starts yielding, and the force received from the anchor bolt 10. Is set smaller than the value of the yield start bending moment when the peripheral edge of the column base 6 starts yielding, and the anchor bolt 10 yields before the steel column 4 and the column base 6. It was.

  For this reason, when the bending moment M is applied to the column base structure 2 shown in FIG. 12, the steel column 4 and the column base metal 6 are tilted so that the left side in FIG. The anchor bolt 10 on the left side receives a load that generates a bending moment M from the column base metal 6 and extends upward in the figure.

  Here, the anchor bolt 10 on the left side in FIG. 13 was elongated due to elastic deformation in the state A to B in FIG. 15 and its length dimension was increased, but in the state B to C in FIG. Yield began beyond this, and the length dimension increased due to plastic deformation.

  When the bending moment M becomes smaller, the anchor bolt 10 on the left side in FIG. 13 is reduced in length by the amount of elongation due to elastic deformation in the state C to D in FIG. The length increased by the plastic deformation in the states B to C remained in the length even in the states C to E.

  When a bending moment in the direction opposite to the bending moment M (counterclockwise direction in FIG. 13) acts, in the process from state E to state I via F, G, H in FIG. The process was the same as the process from state A to E in FIG.

  Therefore, the anchor bolt 10 on the right side in FIG. 13 is the same as the anchor bolt 10 on the left side in FIG. 13 in the process from state E to state I via F, G, H in FIG. A deformation similar to the deformation in the process from the state A to the E occurs.

  In FIG. 15, the area of the quadrilateral formed by the trajectory from the states A to E and the area of the quadrilateral formed by the trajectory from the states E to I are determined by the conventional column base structure 2 between these states. It shows the amount of energy absorption that can be absorbed. For this reason, the conventional column base structure 2 was able to absorb energy without problems in the states A to I.

  However, once the state I in FIG. 15 is reached, as shown in FIG. 14, each of the anchor bolts 10 on the left and right sides in the figure has been extended upward due to plastic deformation. It was not fixed to the bolt 10, and a large gap S was generated between the lower surface of the nut member 12 and the upper surface of the washer 16.

  When a load that generates the bending moment M is applied again in the state I, in the state I to J, that is, until the lower surface of the nut member 12 on the left side in FIG. Meanwhile, the steel column 4 and the column base 6 were tilted so that the left side in the figure was higher than the right side.

  In this state I to J, the load that generates the bending moment M is not transmitted to the anchor bolt 10 from the lower end of the steel column 4 and the column base 6, so the conventional column base structure 2 is in the state I to J, There was a slip phenomenon where no energy was absorbed.

  At this time, since energy is not absorbed in the lower end portion of the steel column 4 in the conventional column base structure 2, the column base metal 6 and the anchor bolt 10, the load that generates the bending moment M in the states I to J is as follows: Without being reduced at all, the beam member or the column member constituting the upper structure above the column base structure 2 is suddenly applied.

  For this reason, the load that generates the bending moment M is not reduced at all, and the beam member or the column member constituting the upper structure may be damaged or broken by being suddenly applied, or the building structure may be collapsed. There was a risk.

  With respect to such a problem, the upper structure above the conventional column base structure 2 can withstand the load that generates the bending moment M by increasing the diameter and thickness of the beam member and the column member. However, on the other hand, there is a problem that the superstructure is increased in size, weight, and cost.

  Further, in the conventional column base structure 2, in order to increase the energy for generating the bending moment M that the anchor bolt 10 can absorb, when the anchor bolt 10 having an increased outer diameter is employed, In addition to increasing the size of the corresponding nut member 12, it is necessary to increase the thickness of the column base 6, which increases the size, weight, and cost of the column base structure 2. .

  Therefore, in view of the above problems, the present invention can improve the energy absorption capacity of the column base structure and prevent damage, breakage, or collapse of the building structure, as well as the column base structure and building structure. It is an object of the present invention to provide a column base structure that can prevent an increase in size, weight, and cost.

In order to solve the above problems, the column base structure according to the present invention is:
The peripheral part of the joint hardware joined to the lower end of the column member is fixed by an anchor bolt protruding upward from the basic concrete, and the column base structure in which the anchor bolt yields before the column member,
The first bending moment at which the anchor bolt starts yielding is set to be larger than the second bending moment at which the peripheral portion of the joint metal starts yielding and 1.5 times or less of the second bending moment. It is characterized by that.

According to such a column base structure of the present invention,
The peripheral part of the joint hardware joined to the lower end of the column member is fixed by an anchor bolt protruding upward from the basic concrete, and the column base structure in which the anchor bolt yields before the column member,
The first bending moment at which the anchor bolt starts yielding is set to be larger than the second bending moment at which the peripheral portion of the joint metal starts yielding and 1.5 times or less of the second bending moment. As a result,
Improve the energy absorption capacity of the column base structure to prevent damage, breakage, or collapse of the building structure, and prevent the column base structure or building structure from becoming large, heavy, or expensive. Can do.

It is a partial section side view showing column base structure 40 concerning one embodiment of the present invention. It is a schematic partial cross-sectional side view for demonstrating the state where the bending moment M was added to the column base structure 40 shown in FIG. It is a schematic partial cross-sectional side view for demonstrating the state where the bending moment M was added to the column base structure 40 shown in FIG. 1, and the anchor bolt 10 yielded. It is a hysteresis diagram which shows roughly the relationship between the bending moment M of the steel column 4 in FIG. 1, and rotation angle (theta). 2 is a schematic diagram of a two-layer model 50. FIG. 4 is a schematic diagram of a four-layer model 52. FIG. It is a hysteresis diagram which shows the relationship between the bending moment M of the steel column 4 in FIG. 12, and rotation angle (theta). It is a hysteresis diagram which shows the relationship between the bending moment M of the steel column 4 in FIG. 1, and rotation angle (theta). FIG. 13 is a hysteresis diagram schematically showing the relationship between the bending moment M of the steel column 4 and the rotation angle θ when the steel column 4 in FIGS. 1 and 12 is joined to the basic concrete 3 by an embedded column base. It is a comparison figure of the column base absorbed energy parameter | index in the two-layer model 50 of the conventional column base structure 2 and the column base structure 40 of this invention. It is a comparison figure of the column base absorbed energy parameter | index in the 4-layer model 52 of the conventional column base structure 2 and the column base structure 40 of this invention. It is a partial cross section side view which shows the conventional column base structure 2. FIG. FIG. 13 is a schematic partial cross-sectional side view for explaining a state in which a bending moment M is applied to the column base structure 2 shown in FIG. 12. FIG. 13 is a schematic partial cross-sectional side view for explaining a state where the bending moment M is applied to the column base structure 2 shown in FIG. 12 and the anchor bolt 10 yields. It is a hysteresis diagram which shows roughly the relationship between the bending moment M of the steel column 4 in FIG. 12, and rotation angle (theta).

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the column base structure which concerns on this invention is demonstrated concretely based on drawing.

  FIGS. 1 to 11 are views referred to for explaining a column base structure 40 according to an embodiment of the present invention. Hereinafter, the same parts as those of the conventional column base structure 2 will be described with the same reference numerals, and the description of the same structure as the conventional one will be omitted except for a part.

  In the column base structure 40 according to the present embodiment, as shown in FIG. 1, a plate-shaped column base metal 42 (joint metal) is provided above the foundation concrete 3 via a mortar 8. The column base metal 42 is made of metal and has both square front and back surfaces.

  The column base metal 42 has its upper surface 42a abutted against the lower end surface of the steel column 4 (column member) and joined together by welding. The steel column 4 has a length in the vertical direction in FIG. 1 and is formed in a hollow rectangular tube shape.

  The upper end portion of the anchor bolt 10 protruding upward from the foundation concrete 3 is inserted into a bolt insertion hole 42 b formed in the column base metal 42.

  The male thread portion formed at the upper end portion of the anchor bolt 10 that protrudes above the column base metal 42 is inserted into the through hole of the washer 16 and screwed to the female thread portion of the nut member 12, so that the steel column 4 is erected and fixed on the foundation concrete 3 via the column base 42 and the mortar 8.

  In the column base metal 42 in the present embodiment, the yield start bending moment Mb (second bending moment) when the peripheral portion of the column base metal 42 starts yielding by the force received from the anchor bolt 10 is the conventional column base structure. 2, the thickness is set to be thinner than the thickness of the conventional column base 6 so that the peripheral edge of the column base 6 starts to yield by the force received from the anchor bolt 10. Has been.

  Further, the column base structure 40 in the present embodiment is configured such that the yield start bending moment Ma (first bending moment) when the anchor bolt 10 starts yielding is the peripheral portion of the column base metal 42 due to the force received from the anchor bolt 10. Is set to be larger than the yield starting bending moment Mb when starting yielding and 1.5 times or less the yield starting bending moment Mb.

  For this reason, when the load that generates the bending moment increases, the peripheral portion of the column base metal 42 starts yielding earlier than the anchor bolt 10.

  Conversely, if the yield start bending moment Ma when the anchor bolt 10 starts yielding is equal to or less than the value of the yield start bending moment Mb when the peripheral edge of the column base metal 42 starts yielding, the bending moment As the load for generating the pressure increases, the anchor bolt 10 yields before the column base metal 42, and the problem of the conventional column base structure 2 cannot be solved.

  Further, when the yield start bending moment Ma when the anchor bolt 10 starts yielding is larger than the value of 1.5 times the yield start bending moment Mb when the peripheral portion of the column base metal 42 starts yielding, Before the anchor bolt 10 yields and undergoes plastic deformation, the plastic deformation of the column base metal 42 proceeds too much, and the portion fixed by the anchor bolt 10 of the column base metal 42 and its periphery are bent more than necessary, and the anchor bolt There is a possibility that the anchor bolt 10 may be broken by pressing 10 toward a direction other than the extending direction.

  Further, the yield start bending moment when the column member 4 starts yielding is such that the anchor bolt 10 yields so that the column member 4 does not yield and plastically deform before the anchor bolt 10 or the column base metal 42. Value of the yield start bending moment Ma when starting the bending, the value of the yield starting bending moment Mb when the peripheral portion of the column base metal 42 starts yielding by the force received from the anchor bolt 10, and the peripheral edge of the column base metal 42 It is set to a value larger than the yield-start bending moment when the part other than the part starts yielding.

  Further, in order to prevent the base concrete 3 and the mortar 8 from compressively yielding and plastically deforming before the column base metal 42, the compressive yield start bending moment when the base concrete 3 and the mortar 8 start the compressive yield is It is set to a value larger than the value of the yield start bending moment Mb when the peripheral portion of the column base metal 42 starts yielding by the force received from the anchor bolt 10.

  Such a column base structure 40 according to the present embodiment is large in the clockwise direction around the rotation center O of the joint portion with the column base metal 42 as shown in FIG. When a load that generates the bending moment M is applied, in the state B to C in FIG. 4, the periphery of the column base metal 42 near the bolt insertion hole 42 b on the left side in FIG. 2 is attached to the anchor bolt 10. 2 so that the left end of the column base metal 42 on the left side in FIG. 2 is located below the plastically deformed portion from the plastically deformed portion. It can be folded into the shape of

  This bent portion of the column base metal 42 is subjected to a load that generates a bending moment in the counterclockwise direction opposite to the bending moment M in the states F to G in FIG. Then, it is folded back in a substantially straight line in the horizontal direction.

  Further, the column base metal 42 to which a load generating the clockwise bending moment M is applied is yielded and plasticized by the force that the right part in FIG. 2 is pressed against the upper surface of the mortar 8 on the foundation concrete 3. It is deformed and bent in a reverse shape so that the right end portion of the column base metal 42 located on the right side in the drawing from the plastically deformed portion is positioned on the upper side.

  Further, the anchor bolt 10 on the left side in FIG. 2 yields beyond its elastic range in the states B to C in FIG. 4 and extends due to plastic deformation to increase its length dimension.

  In the process from state E in FIG. 4 to state I via F, G, H, the process from state A to E in FIG. It is the same.

  Therefore, the anchor bolt 10 on the right side in FIG. 2 is in the state of FIG. 4 of the anchor bolt 10 on the left side in FIG. 2 in the process from the state E in FIG. 4 to the state I via F, G, H. The deformation similar to the deformation in the process from state A to state E via B, C, D occurs.

  In the process from the state E in FIG. 4 to the state I through F, G, H, the column base metal 42 is pressed against the upper surface of the mortar 8 on the foundation concrete 3 in the process from the state E to the state I in FIG. It yields and plastically deforms due to the applied force, and is bent in a reverse shape so that the left end portion of the column base metal 42 on the left side in the drawing is positioned above the plastically deformed portion.

  FIG. 3 shows the column base structure 40 in the states I and J in FIG. 4, since bent portions 42 c that are bent upward in the drawing are formed at the left and right ends of the column base metal 42 in the drawing. The gap S1 between the lower surface of the nut member 12 and the upper surface of the washer 16 on the bent portion 42c of the column base metal 42 is significantly smaller than the gap S in the conventional column base structure 2.

  For this reason, when a load that generates the bending moment M again is applied in the state I, the lower surface of the nut member 12 on the left side in FIG. 3 and the upper surface of the washer 16 on the bent portion 42c of the column base metal 42 are separated. Since the contact is made almost immediately, the slip phenomenon as in the conventional column base structure 2 hardly occurs.

  In this way, the load that generates the bending moment M can be transmitted almost immediately from the lower end of the steel column 4 and the column base metal 42 to the anchor bolt 10, so that the column base structure 40 is in the state shown in FIG. By following a trajectory that approximates elastic deformation along J to K, the lower end of the steel column 4, the column base metal 42, and the anchor bolt 10 can be made to absorb energy.

  For this reason, the beam members and column members constituting the upper structure above the column base structure 40 are not subjected to all the loads that generate the bending moment M, and the upper structure above the column base structure 40 is not It is only necessary to bear a part of the load.

  That is, the column base structure 40 according to the present embodiment absorbs energy by the area Q of the triangle (shaded portion) formed by the locus from the state J to the state N via K and L in FIG. The anchor bolt 10 can bear the load that generates the bending moment M from the lower end of the steel column 4 and the column base metal 42.

  Hereinafter, tests performed on the conventional column base structure 2 and the column base structure 40 according to the present embodiment will be described with reference to FIGS. 5 to 11. In the above test, the two-layer model 50 shown in FIG. 5 and the four-layer model 52 shown in FIG. 6 are tested by applying seismic waves (El Centro NS waves) in a state where a predetermined weight is loaded.

  In the two-layer model 50, as shown in FIG. 5, three column members 54 are arranged at intervals in the left-right direction in the drawing, and these column members 54 are formed on a column base 60 on a base surface 53. It stands up through.

  The four beam members 56 are arranged substantially horizontally with respect to the base surface 53 and arranged in series two by two in two stages, upper and lower. These beam members 56 are rigidly joined to the column members 54 at joints 58 where both ends in the length direction are abutted against the side portions of the column members 54.

  As shown in FIG. 6, in the four-layer model 52, as in the two-layer model 50, three column members 54 are spaced apart from each other in the left-right direction in the figure, and these column members 54 are the basis. It is erected on the surface 53 via the column base 60.

  Eight beam members 56 are arranged substantially horizontally with respect to the base surface 53 and arranged in series, two at a time in four stages. These beam members 56 are rigidly joined to the column members 54 at joints 58 where both ends in the length direction are abutted against the side portions of the column members 54.

  FIG. 7 shows the relationship between the bending moment M and the rotation angle θ of the steel column 4 shown in FIG. 13 obtained as a result of the test using the conventional column base structure 2 for the column base 60 of the two-layer model 50. It is a hysteresis diagram. As shown in FIG. 7, in the conventional column base structure 2, the slip phenomenon as shown from the state I to J in FIG. 15 has arisen.

  On the other hand, FIG. 8 shows the bending moment M of the steel column 4 shown in FIG. 2 obtained as a result of the test using the column base structure 40 according to the present embodiment for the column base 60 of the two-layer model 50. FIG. 6 is a hysteresis diagram showing the relationship between and the rotation angle θ. As shown in FIG. 8, in the column base structure 40 according to the present embodiment, unlike the conventional column base structure 2, the slip phenomenon as shown in the states I to J in FIG. 15 does not occur.

  Here, FIG. 8 shows that the yield start bending moment Ma at which the anchor bolt 10 starts yielding is set to 1.5 times the yield start bending moment Mb at which the peripheral portion of the column base metal 42 starts yielding. Although shown, when the yield start bending moment Ma is set in a range larger than the yield start bending moment Mb and less than the yield start bending moment Mb, the same tendency as in FIG. 8 is shown.

  Further, the column base structure 40 used in the above test has the yield start bending moment Mb of the peripheral part of the column base metal 42 within the above setting range, and the yield of the peripheral part of the column base metal 6 in the conventional column base structure 2. The conditions are the same as those of the conventional column base structure 2 except that the value is smaller than the value of the starting bending moment.

  The four-layer model 52 also showed the same tendency as the two-layer model 50 shown in FIGS.

  10 and 11 are diagrams for comparing the column base absorbed energy index (W1 / W0) of the conventional column base structure 2 and the column base structure 40 according to the present embodiment. FIG. 10 shows a comparison of the column base absorbed energy index in the case of the two-layer model 50, and FIG. 11 shows a comparison of the column base absorbed energy index in the case of the four-layer model 52.

  Here, the column base absorbed energy index is the exposed column base absorbed energy W1 that can be absorbed by the conventional column base structure 2 or the column base structure 40 according to the present embodiment, and the column member 54 in the embedded column base. The column base absorption energy that can be absorbed by the column base structure is increased as the value of the column base absorption energy index increases. The amount will be large.

  FIG. 9 shows the bending moment M and the rotation angle of the column member 54 in the case where the lower end portion of the column member 54 is embedded below the base surface 53 without using the column member 54 in the embedded column base, that is, the column base portion 60. It is a hysteresis diagram which shows the relationship with (theta).

  The column member 54 in the embedded column base can absorb energy by the area of the quadrilateral formed by the locus from the state B to the state B via C, D, E, and F in FIG. This becomes the embedded column base absorbed energy W0.

  On the other hand, the exposed-type column base absorbed energy W1 is calculated from the hysteresis diagram of the conventional column base structure 2 or the column base structure 40 according to the present embodiment as shown in FIGS. Yes.

  In the case of the two-layer model 50 shown in FIG. 10, each of the three buildings a, b, c of the conventional column base structure 2 has a column base absorbed energy index value of 0.25 or less, In each of the three buildings a, b, c of the column base structure 40 according to the present embodiment, the value of the column base absorbed energy index is 0.5 or more.

  Here, each of the three buildings a, b, and c is set so that the strength of the column member and the beam member is different from that of other buildings.

  In the case of the four-layer model 52 shown in FIG. 11, each of the three buildings a, b, c of the conventional column base structure 2 has a column base absorbed energy index value of 0.15 or less, Each of the three buildings a, b, and c of the column base structure 40 according to the present embodiment has a column base absorbed energy index value of 0.3 or more.

  As shown in FIGS. 10 and 11, the column base structure 40 according to the present embodiment can increase the amount of absorbed column base as compared with the conventional column base structure 2.

  As shown in FIG. 3, the column base structure 40 according to the present embodiment has a nut member attached to the anchor bolt 10 by forming bent portions 42 c at both left and right ends of the column base metal 42. The gap S <b> 1 between the lower surface of 12 and the upper surface of the washer 16 on the bent portion 42 c of the column base 42 can be reduced.

  In addition, as shown in FIG. 4, the column base structure 40 according to the present embodiment can increase the amount of energy that can be absorbed by the column base structure 40 even after the anchor bolt 10 yields.

  That is, the column base structure 40 according to the present embodiment does not cause the slip phenomenon as in the conventional column base structure 2, so that the bending moment M is applied to the lower end portion of the steel column 4, the column base bracket 42 and the anchor bolt 10. Since a part of the generated load is applied, the load that generates the bending moment M is not applied to the beam member, the column member, etc. constituting the upper structure above the column base structure 40, and the column base structure The superstructure above 40 need only bear part of the load.

  For this reason, it is possible to prevent column members, beam members, and the like constituting the upper structure above the column base structure 40 from being damaged or broken, and to prevent the building structure from collapsing, and constitute the upper structure. It is possible to prevent an increase in size, weight, and cost of column members and beam members.

  In addition, the column base structure 40 according to the present embodiment does not need to employ the anchor bolt 10 having a large outer diameter, so that the anchor bolt 10 and the column base hardware 42 constituting the column base structure 40 are enlarged. Therefore, weight and price can be prevented.

  Therefore, as explained above, according to the column base structure 40 according to the present embodiment, the energy absorption capacity of the column base structure 40 is improved to prevent damage, breakage, or collapse of the building structure. In addition, it is possible to prevent the column base structure 40 and the building structure from becoming large, heavy, and expensive.

  In addition, this invention is not limited only to the said embodiment, If it is in the range which can achieve the objective of this invention, various changes are possible about a column base structure.

  For example, in the column base structure 40 according to the above-described embodiment, the case where the column base hardware 42 is a flat plate having both square front and back surfaces has been described. It may be a rectangle.

  Further, the column base hardware may be configured by a bottom plate portion and a support base portion in which a central portion of the upper surface of the bottom plate portion protrudes upward from the peripheral edge portion thereof, like the column base hardware according to Patent Document 2. Also, other shapes may be used.

  Further, in the column base structure 40 according to the embodiment, the steel column 4 whose lower end surface is joined to the column base metal 42 is formed in a rectangular tube shape, but is not limited to this shape, for example, It may be formed in a cylindrical shape. Moreover, the steel column may be formed in a solid shape.

  Further, in the column base structure 40 according to the above-described embodiment, the male screw portion formed on the upper end portion of the anchor bolt 10 protruding upward from the column base metal 42 is screwed to the female screw portion of one nut member 12. However, two or more nut members 12 (such as double nuts) may be attached.

  Further, in the column base structure 40 according to the embodiment, in the basic concrete 3, the male screw portion formed at the lower end portion of the anchor bolt 10 is screwed to the female screw portion of one nut member 14. Two or more nut members 14 may be attached, or a fixing plate 18 may be provided between the two nut members 14.

2 column base structure 3 foundation concrete 4 steel column 6 column base metal 6a upper surface 6b bolt insertion hole 8 mortar 10 anchor bolt 12, 14 nut member 16 washer 18 fixing plate 40 column base structure 42 column base metal 42a upper surface 42b bolt insertion hole 42c Bending portion 50 Two-layer model 52 Four-layer model 53 Base surface 54 Column member 56 Beam member 58 Joint portion 60 Column base A, B, C, D, E, F, G, H, I, J, K, L, N state a, b, c Building M Bending moment Ma, Mb Yield starting bending moment O Center of rotation Q Area S, S1 Clearance θ Angle

In order to solve the above problems, the column base structure according to the present invention is:
Periphery of the joining hardware joined to a lower end portion of the pillar member, the nut member is fixed on the foundation concrete by being fastening screws to the upper end of the anchor bolt projecting upward from the foundation concrete, said post member A column base structure in which the anchor bolt yields earlier than,
The first bending moment at which the anchor bolt starts yielding is set to be larger than the second bending moment at which the peripheral portion of the joint metal starts yielding and 1.5 times or less of the second bending moment. It is,
The yield start bending moment when the column member starts yielding is larger than the first bending moment, the second bending moment, and the yield starting bending moment when the other than the peripheral edge of the joint metal starts yielding. Set to the value
A compression yield start bending moment when the foundation concrete starts compression yielding is set to a value larger than the second bending moment .

Claims (1)

The peripheral part of the joint hardware joined to the lower end of the column member is fixed by an anchor bolt protruding upward from the basic concrete, and the column base structure in which the anchor bolt yields before the column member,
The first bending moment at which the anchor bolt starts yielding is set to be larger than the second bending moment at which the peripheral portion of the joint metal starts yielding and 1.5 times or less of the second bending moment. The column base structure is characterized by that.

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