Abstract:
Exemplary embodiments of a joint structure for an earthquake-resistant member can be provided at an intersect portion of a steel column extending in a substantially vertical direction and a steel beam extending in a substantially horizontal direction, and facilitated for joining an earthquake-resistant member to the intersect portion. The joint structure can include: a first joining plate located along the steel column without fixing the first joining plate to the steel column; a second joining plate located along the steel beam without fixing the second joining plate to the steel beam; a first movement-restraint member which restrains the first joining plate; and a second movement-restraint member which restrains the second joining plate. The earthquake-resistant member can be joined to the first joining plate and the second joining plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]     The present application claims priority from Japanese Patent Application No. 2006-106342, filed Apr. 7, 2006, the entire disclosures and content of which is incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to a joint structure for an earthquake-resistant member and a method for producing the same.  
       BACKGROUND INFORMATION  
       [0003]     For an earthquake strengthening method for a structure, joining an earthquake resisting element such as a brace to an intersect portion of a column and a beam can be generally established.  
         [0004]     Conventionally, in a case where the brace is joined to the intersect portion of the column and the beam, a gusset plate can generally be disposed between the intersect portion and the brace. For example, Japanese Unexamined Patent Application, First Publication No. 2000-186371 describes a joint structure including a column side gusset plate  110  which can be disposed on a column  101  and provided for joining the column  101  to a brace member  103 . A beam side gusset plate  111  can be disposed on a beam  102  and may be provided for joining the beam  102  to the brace member  103  is disclosed. Such exemplary arrangement is shown in  FIG. 10 .  
         [0005]     The column side gusset plate  110  has an elongate-rectangular shape in a square view, and the beam side gusset plate  111  also has an elongate-rectangular shape in a square view. The column side gusset plate  110  protrudes from a steel tubing web toward the brace member  103  so that the tip of the column side gusset plate  110  is tapered. The beam side gusset plate  111  protrudes from the middle of the upper portion of an H-section steel forming the beam  102  vertically upward. When the column is a steel tube, the column side gusset plate  110  is welded to the column  101 , and the beam side gusset plate  111  is welded to the beam  102 . A gusset plate  112  having an end plate  108  can be joined to an end portion of the brace member  103 .  
         [0006]     When joining members (e.g., the column side gusset plate and the beam side gusset plate) are welded to the intersect portion of the column and the beam, the deformation of the column and the beam is restrained. Therefore, the deformation property of the entire steel structure can become low. According to the Japanese earthquake-resistant standard, if the deformation property becomes high, the deformability and damping factor of structure (value of Ds) can be improved. Thus, may be is possible to decrease shear force of an earthquake in the secondary seismic design.  
         [0007]     Generally, the structure of a pure moment resisting frame should withstand a large story-deformation angle to reduce the shear force of the earthquake. The story-deformation angle is a rate of the relative story displacement in the horizontal direction of each of the floors to the height of the relevant floor. For example, as shown in  FIG. 11 , when the relative story displacement in the horizontal direction is δ, and the height of the relevant floor is h, then the story-deformation angle is represented by δ/h (rad).  
         [0008]     For instance, a moment resisting frame including braces can occasionally need to withstand the same story-deformation angle. Specifically, when the brace is a buckling restraint brace, the same story-deformation angle should be used.  
         [0009]     If the steel structure is a pure moment resisting frame, the steel structure can withstand a large story-deformation angle as a result of using suitable welding. However, when a gusset plate for the brace is attached to the steel structure of the moment resisting frame, the flexible length of a column or a beam can become short, and stress concentration may occur at an end of the gusset plate. Therefore, the steel structure can hardly obtain the high deformation property so as to withstand the large story-deformation angle.  
         [0010]     Accordingly, there is a need to overcome the deficiencies as described herein above.  
       OBJECTS AND SUMMARY OF EXEMPLARY EMBODIMENTS  
       [0011]     One of the exemplary objects of the present invention is to solve the above-described problem and provide a joint structure for an earthquake-resistant member and a construction method for the same which provides an improvement of the earthquake resistance of the structure as a result of enlarging the story-deformation angle in the joint structure of an earthquake-resistant member such as a brace and an intersect portion of a column and a beam.  
         [0012]     The first exemplary embodiment of the joint structure for an earthquake-resistant member according to the present invention is provided at an intersect portion of a steel column extending in a substantially vertical direction and a steel beam extending in a substantially horizontal direction, and is for joining an earthquake-resistant member to the intersect portion. The exemplary joint structure of the present invention can include: a first joining plate located along the steel column without fixing the first joining plate to the steel column; a second joining plate located along the steel beam without fixing the second joining plate to the steel beam; a first movement-restraint member provided on the steel column so as to contact an end portion of the first joining plate, and which restrains the first joining plate so that the first joining plate does not move in the direction of the steel column; and a second movement-restraint member provided on the steel beam so as to contact an end portion of the second joining plate, and which restrains the second joining plate so that the second joining plate does not move in the direction of the steel beam. The earthquake-resistant member is joined to the first joining plate and the second joining plate.  
         [0013]     The second exemplary embodiment of the joint structure for an earthquake-resistant member according to the present invention can be provided at a intersect portion of a steel column extending in a substantially vertical direction and a steel beam extending in a substantially horizontal direction, and is used for joining an earthquake-resistant member to the intersect portion. The exemplary joint structure of the present invention can include: a first joining plate located along one of the steel column and the steel beam without fixing the first joining plate to the one; and a first movement-restraint member provided on the one so as to contact with an end portion of the first joining plate, and which restrains the first joining plate so that the first joining plate does not move in the direction of the one. The earthquake-resistant member can be joined to the first joining plate and the other of the steel column and the steel beam.  
         [0014]     The first exemplary embodiment of the construction method for a joint structure of an earthquake-resistant member according to the present invention can be for joining an earthquake-resistant member to an intersect portion of a steel column extending in a substantially vertical direction and a steel beam extending in a substantially horizontal direction. The exemplary construction method of the present invention can include: locating a first joining plate along the steel column without fixing the first joining plate to the steel column; fixing the first movement-restraint member to the steel column so as to contact an end portion of the first joining plate; locating a second joining plate along the steel beam without fixing the second joining plate to the steel beam; fixing the second movement-restraint member to the steel beam so as to contact an end portion of the second joining plate; and joining the earthquake-resistant member to the first joining plate and the second joining plate. The first movement-restraint member restrains the first joining plate so that the first joining plate does not move in the direction of the steel column, and the second movement-restraint member restrains the second joining plate so that the second joining plate can be prevented or limited from moving in the direction of the steel beam.  
         [0015]     The second exemplary embodiment of the construction method for a joint structure of an earthquake-resistant member according to the present invention can be for joining an earthquake-resistant member to an intersect portion of a steel column extending in a substantially vertical direction and a steel beam extending in a substantially horizontal direction. The exemplary construction method of the present invention can include: locating a first joining plate along one of the steel column and the steel beam without fixing the first joining plate to the one; fixing the first movement-restraint member to the one so as to contact an end portion of the first joining plate; and joining the earthquake-resistant member to the first joining plate and the other of the steel column and the steel beam. The first movement-restraint member may restrain the first joining plate so that the first joining plate can be prevented or limited from moving in the direction of the one.  
         [0016]     According to one exemplary embodiment of the present invention, since the second joining plate contacts the steel beam without being fixed to the steel beam, if a large earthquake occurs and when the steel beam is bent vertically by a force of the earthquake, the steel beam may not be restrained by the second joining plate. Therefore, the deformation property of the steel beam can be improved, and thereby the steel structure can withstand a large story-deformation angle.  
         [0017]     Similarly, since the first joining plate just contacts the steel column without being fixed to the steel column, if the steel column is bent horizontally by the force of the earthquake, the steel column is not restrained by the first joining plate. Therefore, the deformation property of the steel column is improved, and thereby the entire steel structure can obtain remarkable deformation property.  
         [0018]     These and other objects, features and advantages of the present invention will become apparent upon reading the following detailed description of embodiments of the invention, when taken in conjunction with the appended claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying figures showing illustrative embodiments of the invention, in which:  
         [0020]      FIG. 1  is a side view showing a first exemplary embodiment of a joint structure for an earthquake-resistant member according to the present invention;  
         [0021]      FIG. 2  is a sectional view taken along a line A-A of the joint structure shown in  FIG. 1 ;  
         [0022]      FIG. 3  is a sectional view taken along a line B-B of the joint structure shown in  FIG. 1 ;  
         [0023]      FIG. 4  is a view illustrating exemplary effects of the joint structures shown in  FIG. 1 ;  
         [0024]      FIG. 5  is a view showing a second exemplary embodiment of the joint structure for the earthquake-resistant member according to the present invention;  
         [0025]      FIG. 6  is a sectional view taken along a line C-C of the joint structure shown in  FIG. 5 ;  
         [0026]      FIG. 7  is a sectional view taken along a line D-D of the joint structure shown in  FIG. 5 ;  
         [0027]      FIG. 8  is a view showing a third exemplary embodiment of the joint structure for the earthquake-resistant member according to the present invention;  
         [0028]      FIG. 9  is a view showing a fourth exemplary embodiment of the joint structure for the earthquake-resistant member according to the present invention;  
         [0029]      FIG. 10  is a view illustrating the effects provided by a conventional joint structure; and  
         [0030]      FIG. 11  is a view illustrating the effects of a story-deformation angle of an exemplary steel structure. 
     
    
       [0031]     Throughout the figures, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components or portions of the illustrated embodiments. Moreover, while the subject invention will now be described in detail with reference to the figures, it is done so in connection with the illustrative embodiments. It is intended that changes and modifications can be made to the described embodiments without departing from the true scope and spirit of the subject invention as defined by the appended claims.  
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0032]     Hereunder, exemplary embodiments of the joint structure for an earthquake-resistant member and construction method for the joint structure in a reinforced structure will be explained with reference made to the figures.  
         [0000]     First Exemplary Embodiment  
         [0033]      FIGS. 1-3  show an exemplary embodiment of an intersect portion of a steel column  1  formed by a square-shaped steel tube and a steel beam  2  which is formed by an H-section steel. The joint structure of this exemplary embodiment can include a connector  5  for connecting an earthquake-resistant member  4 , such as a brace to the intersect portion of the steel column  1  and the steel beam  2 . The connector  5  can include a first joining plate  6  which contacts a side surface of the steel column  1 , a second joining plate  7  put on the steel beam  2 , and a gusset plate  8  welded to the first joining plate  6  and the second joining plate  7  so as to be at least approximately orthogonal to each of the first joining plate  6  and the second joining plate  7 . The earthquake-resistant member  4  can be connected to the gusset plate  8  through a splice plate  10  using connecting bolts  11 .  
         [0034]     The first joining plate  6  is preferably not fixed to the steel column  1  by, e.g., welding and preferably only contacts the steel column  1 . Similarly, the second joining plate  7  is preferably not fixed to the steel beam  2  by, e.g., welding but preferably only contacts the steel beam  2 . For example, the connector  5  can be provided for transmitting the pulling force acting on the earthquake-resistant member  4  at the time of an earthquake or the like to the steel column  1  and the steel beam  2 . Therefore, the connector  5  should be fixed to both of the steel column  1  and the steel beam  2 . Since preferably only the first joining plate  6  and the second joining plate  7  respectively contact the steel column  1  and the steel beam  2  without being fixed to them, the pulling force acting from the earthquake-resistant member  4  would preferably not be transmitted to the steel column  1  and the steel beam  2 .  
         [0035]     Consequently, the pulling force acting from the earthquake-resistant member  4  can be divided between the vertical force acting in a direction of pulling up the connector  5  and the horizontal force acting in the horizontal direction when the pulling force acts on the connector  5 . For example, according to this exemplary embodiment, a member which can resist the vertical force and another member which can resist the horizontal force may be respectively disposed to the steel column  1  and the steel beam  2 . As a result, the vertical force can be transmitted to the steel column  1  as axial force of the column  1 , and the horizontal force can be transmitted to the steel beam  2  as axial force of the beam  2 .  
         [0036]     In particular, a first movement-restraint member  14  can be fixed to a side surface of the steel column  1 . The first movement-restraint member  14  can be located so as to contact an end portion  6   a  of the first joining plate  6 . In addition, a second movement-restraint member  15  may be fixed to an upper side surface of the steel beam  2 . The second movement-restraint member  15  can be located so as to contact an end portion  7   a  of the second joining plate  7 .  
         [0037]     Each of the first movement-restraint member  14  and the second movement-restraint member  15  can be formed by a rectangular steel plate which may have a predetermined thickness and a predetermined size (e.g., square). The first movement-restraint member  14  may be fixed to the steel column  1  by, e.g., fillet welding  41 , and the second movement-restraint member  15  can be fixed to the steel beam  2  by, e.g., the fillet welding  41 . It should be understood that other arrangements, including but not limited to a fastening device, such as a bolt, may be used as instead of the fillet welding  41 .  
         [0038]     The vertical force acting on the end portion  6   a  of the first joining plate  6  can be loaded to an end portion  16  of the first movement-restraint member  14 . Therefore, it may be preferable that the first joining plate  6  and the first movement-restraint member  14  be located so that an end surface of the first joining plate  6  can closely contact an end surface of the first movement-restraint member  14 . Further, the horizontal force acting on the end portion  7   a  of the second joining plate  7  is loaded to an end portion  17  of the second movement-restraint member  15 . Therefore, it is preferable that the second joining plate  7  and the second movement-restraint member  15  be located so that an end surface of the second joining plate  7  can closely contact an end surface of the second movement-restraint member  15 .  
         [0039]     In the joint structure of this exemplary embodiment as discussed above, when the pulling force acts on the earthquake-resistant member  4  such as the brace at the time of an earthquake, the vertical force can act on the first joining plate  6  and the horizontal force may act on the second joining plate  7  based on the pulling force. The vertical force acting on the first joining plate  6  may be loaded to the first movement-restraint member  14 , and then the first movement-restraint member  14  can transmit the vertical force to the steel column  1  as the axial force thereof. The horizontal force acting on the second joining plate  7  may be loaded to the second movement-restraint member  15 , and then the second movement-restraint member  15  can transmit the horizontal force to the steel beam  2  as the axial force thereof. For example, when the pulling force acts on the earthquake-resistant member  4 , the reinforced structure can accept the vertical force acting on the connector  5  based on the pulling force as the axial force of the steel column  1 . Similarly, the reinforced structure can accept the horizontal force acting on the connector  5  based on the pulling force as the axial force of the steel beam  2 .  
         [0040]     Further, the earthquake-resistant member  4  can contact the steel column  1  through the first joining plate  6  of the connector  5 , and may contact the steel beam  2  through the second joining plate  7  of the connector  5 . Therefore, when a compression force acts on the earthquake-resistant member  4 , the force acting on the connector  5  on the ground of the compression force can be transmitted to the steel column  1  and the steel beam  2 , which may form structural members, e.g., such as a bearing force.  
         [0041]     The vertical force of the bearing force transmitted to the structural members can be transmitted to the steel column  1  through the web of the steel beam  2 . Therefore, the steel beam  2  located in the vicinity of the connection portion of the column and the beam should preferably have sufficient strength and rigidity so that the vertical force of the bearing force can transmit from the beam to the column. It is possible for the web of the steel beam  2  to be reinforced.  
         [0042]     According to this exemplary embodiment of the joint structure as described above, since the second joining plate  7  preferably only contacts the steel beam  2  without being fixed to the steel beam  2 , if a large earthquake occurs and when the steel beam  2  is bent vertically by a force of the earthquake, the steel beam  2  would likely not be restrained by the connector  5 . Therefore, the deformation property of the steel beam can be improved. Similarly, since the first joining plate  6  preferably just contacts the steel column  1  without being fixed to the steel column  1 , if the steel column  1  is bent horizontally by the force of the earthquake, the steel column  1  would likely not be restrained by the connector  5 . Therefore, the deformation property of the steel column  1  can be improved.  
         [0043]      FIG. 4  shows the exemplary intersect portion of the column and the beam when a large earthquake occurs and the structure deforms in the horizontal direction. Since the second joining plate  7  can contact the steel beam  2  without being fixed to the steel beam  2 , the steel beam  2  (which is bent vertically by a force of the earthquake) would likely not be restrained by the connector  5 . Therefore, the steel beam  2  can follow the deformation of the structure without breaking and cracking until a large story-deformation angle is generated. Similarly, when the steel column  1  is bent horizontally, since the first joining plate  6  can contact the steel column  1  without being fixed to the steel column  1 , the steel column  1  (which is bent horizontally by a force of the earthquake) would likely not be restrained by the connector  5 .  
         [0044]     For example, if the connector  5  is conventionally fixed to the intersect portion of the steel column  1  and the steel beam  2 , the steel column  1  and the steel beam  2  can be restrained by the connector  5  so as to hardly deform, and then the rigidity of the steel column  1  and the steel beam  2  by appearance can become high. However, the deformation property of the steel column  1  and the steel beam  2  can become low. According to this exemplary embodiment, the first joining plate  6  can contact the steel column  1  without being fixed to the steel column  1 , and the second joining plate  7  may contact the steel beam  2  without being fixed to the steel beam  2 . Therefore, the deformation property of the steel column  1  and the steel beam  2  may be improved. As a result, the earthquake resistance can also be improved.  
         [0045]     According to this exemplary embodiment the joint structure described above, when the compression force acts on the earthquake-resistant member  4 , the force acting on the connector  5  based on the compression force can be transmitted to the steel column  1  and the steel beam  2  (which form structural members) as bearing force. Further, when the pulling force acts on the earthquake-resistant member  4 , the steel column  1  can accept the vertical force acting on the connector  5  based on the pulling force as the axial force of the steel column  1 , and the steel beam  2  can accept the horizontal force acting on the connector  5  based on the pulling force as the axial force of the steel beam  2 . Therefore, if the exemplary construction described above is utilized so as to focus on the earthquake resistance, negative effects due to the construction can be removed or reduced.  
       Second Exemplary Embodiment  
       [0046]     With respect to  FIGS. 5-7 , if a large earthquake occurs and when the steel beam  2  is bent vertically (as shown in  FIG. 4 ), stiffening ribs  20  may be respectively disposed on an upper surface of the first movement-restraint member  14  and an upper surface of the second movement-restraint member  15 . The stiffening rib  20  of the first movement-restraint member  14  can prevent the first movement-restraint member  14  from focally bending by the horizontal force acting on the end portion  16  of the first movement-restraint member  14 . The stiffening rib  20  of the second movement-restraint member  15  can prevent the second movement-restraint member  15  from focally bending by the upward force acting on the end portion  17  of the second movement-restraint member  15 .  
       Third Exemplary Embodiment  
       [0047]     As shown in  FIG. 8 , a notch  26  can be formed at the end portion  7   a  of the second joining plate  7 , and the second movement-restraint member  15  may be engaged with the notch  26 . Therefore, it is possible to prevent and/or limit the second movement-restraint member  15  from separating from the plane of structure of the earthquake-resistant member  4 . For example,  FIG. 8  shows that the notch  26  can be formed at the end portion  7   a  of the second joining plate  7 , which contacts the steel column  25 . It should be understood that a notch  26  can be formed at the end portion  6   a  of the first joining plate  6 , and the first movement-restraint member  14  may be engaged with the notch  26 . Therefore, it is possible to prevent and/or limit the first movement-restraint member  14  from separating from the plane of structure of the earthquake-resistant member  4 . Further, in this exemplary embodiment, the steel column  25  can be formed by the H-section steel. It should be understood that the shape of the column and the beam is not limited.  
       Fourth Exemplary Embodiment  
       [0048]      FIG. 9  shows that the second joining plate  7  and the first movement-restraint member  15  can be removed, and the gusset plate  8  may be fixed to the upper surface of the steel beam  2  by, e.g., welding. The first joining plate  6  is preferably not fixed to the steel column  1 , and likely only contacts the steel column  1 . According to this exemplary embodiment, the first joining plate  6  may contact the steel column  1  without being fixed to the steel column  1 , and thereby the deformation property of the steel column  1  may be improved. As a result, the earthquake resistance can also be improved.  
         [0049]     As shown in the exemplary embodiment of  FIG. 9 , the first joining plate  6  is preferably not fixed to the steel column  1 , and the gusset plate  8  can be preferably fixed to the steel beam  2 . It should be understood that the second joining plate  7  should be unfixed to the steel beam  2 , and the gusset plate  8  can be fixed to the steel column  1 . Therefore, the deformation property of the steel beam  2  may be improved. As a result, the earthquake resistance can also be improved.  
         [0050]     The foregoing merely illustrates the principles of the invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, structures, arrangements and methods which, although not explicitly shown or described herein, embody the principles of the invention and are thus within the spirit and scope of the present invention. In addition, to the extent that the prior art knowledge has not been explicitly incorporated by reference herein above, it is explicitly being incorporated herein in its entirety. All publications referenced herein above are incorporated herein by reference in their entireties.