Patent Publication Number: US-8984825-B2

Title: Column shoe

Description:
BACKGROUND OF THE INVENTION 
     The object of the invention is a column shoe according to the preamble of claim  1 . 
     The invention relates to column shoes which are used in lower end corners and sides of steel concrete columns or corresponding concrete element columns for securing the column to the bolts in the column base structure. 
     From publication FI 118186 a column shoe for securing steel concrete columns to a base is known. The column shoe comprises a baseplate provided with a bolt hole and a sideplate secured to the baseplate by welding in order to form a bolt housing. The column shoe further comprises main attachments fixed to the bolt housing for securing the column shoe and the steel concrete column together. Column shoes of this type are also known from publications FI 95164 and SE 511 606. 
     One problem with these known column shoes is the eccentricity between the anchor bolt and the reinforcement bars serving as main attachments of the column shoe. Eccentricity generates horizontal forces on steel concrete column, which horizontal forces have to be encountered by adding reinforcement to the column. Eccentricity also increases internal stresses in the column shoe and creates need for rear attachment when column shoe is under compressive load. One further problem with these known column shoes is the connection between baseplate and sideplate, which is a welded connection and which for this reason generates stress peaks. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The aim of the invention is to solve the above problems. 
     The object of the invention is obtained by the column shoe according to independent claim  1 . 
     Preferred embodiments of the invention are described in dependent claims. 
     The invention is based on the idea that, since the bolt housing is fabricated by casting such that the bolt housing comprises a single-piece casting comprising a baseplate and a sideplate, no stress peaks are generated between the baseplate and the sideplate. This is because as a result of casting there is created a joint of uniform quality between the baseplate and the sideplate. 
     Another advantage obtained by the solution according to the invention is that, since a hole is formed in the bolt housing for securing the attachment unit to the bolt housing, which hole is coaxial with the bolt hole in the baseplate of the bolt housing, no rear attachment is in practice needed in the column shoe according to the invention in order to transfer forces. In general, such rear attachments must be used in order to transmit to the steel concrete column the lower horizontal force of the horizontal force couple generated by the eccentric position relative to the bolt situated at the location of the attachment unit and the bolt hole. In the solution according to the invention, due to the coaxiality of the hole and the bolt hole, the attachment unit, such as a reinforcement bar and underlying vertical anchor bolt arranged to the base, will at least partly, more preferably entirely, be situated substantially on the same axis, whereupon no eccentricity will be formed between the anchor bolt and the reinforcement bar. Since there is no eccentricity between the anchor bolt and the attachment unit, such as a reinforcement bar, there is no need for additional hooks in steel concrete column in order to take horizontal forces caused by eccentricity when column shoe is tension loaded. Thus, reinforcement of steel concrete column is reduced and simplified. 
     Due to the coaxiality column shoe has no stresses caused by eccentricity. This results in that the static model of the bolt housing is simplified. This also results in that the shape and dimensions of the bolt housing may be optimized from new and more simple starting points. Moreover, the capacity of the column shoe may be proved easily in a simple axial tension test without casting the product into the concrete. 
     Due to the coaxiality rear attachment is not needed for taking horizontal force caused by eccentricity when the column shoe is under compression load. Since rear attachment is not needed and since the shape and dimensions of the bolt housing may be optimized, the amount of steel in the column shoe is reduced and manufacturing costs of the column shoe are reduced. 
     Since the wall structure of the bolt housing is tapering in direction of the sleeve structure according to the invention, the steel may be positioned in an advantageous way in relation to forces, so that a dome-like structure is formed, wherein forces follow the shortest path. In consequence the structures are not exposed to additional stresses. In that case also savings may be made in the amount of materials. 
     By the solution of the invention it is possible to make a combination of column shoe-bolt with height of one storey, wherein the attachment unit of the column shoe serves simultaneously as column&#39;s main bar and coupler bolt. Total amount of steel in the column is reduced since no overlappings of reinforcement bar between column shoes, attachment unit of the column and anchor bolt are needed. 
     During transport and stocking bolt housings and column shoes take only little space. 
     Column shoe may be fabricated entirely without welding. A threaded reinforcement bar may serve as main attachment, or a rebar coupler pressed onto the reinforcement bar may be threaded in the threadings of the hole in the upper structure of the bolt housing. Alternatively the reinforcement bar serving as main attachment may be pressed directly in the hole of the upper structure of the bolt housing. 
     The bolt housing may include one or more attachment tugs formed during casting. Attachment lugs may also allow to increase bolt housing rigidity and to enhance attachment to the concrete. Lugs may also be used to secure column shoes together, for example by means of plates, such as hole plates, spiral rods, round rods, reinforcement bars or cable loops. 
     Bolt housings and their attached reinforcement bars may also be used as draw couplers of the bar like elements. 
    
    
     
       LIST OF FIGURES 
       Preferred embodiments of the invention will now be further described with reference to the accompanying Figures, in which: 
         FIG. 1  shows a first preferred embodiment of the bolt housing of column shoe obliquely from above; 
         FIG. 2  shows the bolt housing of column shoe shown in  FIG. 1  obliquely from below; 
         FIG. 3  shows the bolt housing of column shoe shown in  FIG. 1  directly from side; 
         FIG. 4  shows the bolt housing of column shoe shown in  FIG. 1  directly from front; 
         FIG. 5  shows the bolt housing of column shoe shown in  FIG. 1  directly from above; 
         FIG. 6  shows the bolt housing of column shoe shown in  FIG. 1  sectioned along line A-A of  FIG. 5 ; 
         FIG. 7  shows the bolt housing of column shoe shown in  FIG. 1  sectioned along line B-B of  FIG. 5 ; 
         FIG. 8  shows a second preferred embodiment of the bolt housing of column shoe obliquely from above; 
         FIG. 9  shows the bolt housing of column shoe shown in  FIG. 8  obliquely from below; 
         FIG. 10  shows the bolt housing of column shoe shown in  FIG. 8  directly from side; 
         FIG. 11  shows the bolt housing of column shoe shown in  FIG. 8  directly from front; 
         FIG. 12  shows the bolt housing of column shoe shown in  FIG. 8  directly from above; 
         FIG. 13  shows the bolt housing of column shoe shown in  FIG. 8  sectioned along line A-A of  FIG. 12 ; 
         FIG. 14  shows the bolt housing of column shoe shown in  FIG. 8  sectioned along line B-B of  FIG. 12 ; 
         FIG. 15  shows a third preferred embodiment of the bolt housing of column shoe obliquely from above; 
         FIG. 16  shows the bolt housing of column shoe shown in  FIG. 15  obliquely from below; 
         FIG. 17  shows the bolt housing of column shoe shown in  FIG. 15  directly from side; 
         FIG. 18  shows the bolt housing of column shoe shown in  FIG. 15  directly from front; 
         FIG. 19  shows the bolt housing of column shoe shown. in  FIG. 15  directly from above; 
         FIG. 20  shows the bolt housing of column shoe shown in  FIG. 15  sectioned along line A-A of  FIG. 19 ; 
         FIG. 21  shows the bolt housing of column shoe shown in  FIG. 15  sectioned along line B-B of  FIG. 19 ; 
         FIG. 22  shows a fourth preferred embodiment of the bolt housing of column shoe obliquely from above; 
         FIG. 23  shows the bolt housing of column shoe shown in  FIG. 22  obliquely from below; 
         FIG. 24  shows the bolt housing of column shoe shown in  FIG. 22  directly from side; 
         FIG. 25  shows the bolt housing of column shoe shown in  FIG. 22  directly from front; 
         FIG. 26  shows the bolt housing of column shoe shown in  FIG. 22  directly from above; 
         FIG. 27  shows the bolt housing of column shoe shown in  FIG. 22  sectioned along line A-A of  FIG. 26 ; 
         FIG. 28  shows the bolt housing of column shoe shown in  FIG. 22  sectioned along line B-B of  FIG. 26 ; 
         FIGS. 29 and 30  show the bolt housing of column shoe according to  FIG. 1 , to which an attachment unit in the form of a reinforcement bar is secured; 
         FIGS. 31 and 32  show the bolt housing of column shoe according to  FIG. 1 , to which an attachment unit in the form of a reinforcement bar is secured and on the baseplate of which an anchor bolt is secured; 
         FIGS. 33 and 34  show the bolt housing of column shoe according to  FIG. 1 , to which an attachment unit in the form of a reinforcement bar is secured and on the baseplate of which an anchor bolt is secured and wherein the edge of the baseplate is moreover provided with holes for securing the hole plates; 
         FIGS. 35 and 36  show the bolt housing of column shoe shown in  FIGS. 33 and 34  in a state in which hole plates are secured to the baseplate; and 
         FIG. 37  shows the connection point between the steel concrete column and the base partly sectioned. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The object of the invention is a column shoe (not referenced) for securing steel concrete columns  1  such as concrete column elements to a base  2 , such as a foundation of building or corresponding load-bearing structural element. 
     The column shoe comprises a bolt housing  3 , which comprises a baseplate  5  provided with a bolt hole  4 , and an upper structure  6  which is connected to a baseplate  5  and to which at least one attachment unit  7  is connected for securing the column shoe and the steel concrete column  1  together by casting the attachment unit  7  to the steel concrete column  1 . Also a portion of the bolt housing  3 , especially a portion of the upper structure  6  of the bolt housing  3 , is casted in this same occasion to the steel concrete column  1 . 
       FIGS. 29 and 30  show an example of the column shoe. 
       FIG. 37  shows partly sectioned an example of the connection point between the steel concrete column  1  and the base  2 , wherein column shoe has been used for securing the steel concrete column  1  to the base  2 . In  FIG. 37  the vertical anchor bolt  8 , partly cast to the base  2 , traverses the bolt hole  4  in the baseplate  5  of the bolt housing  3 . Anchor bolt  8  is provided with threadings (not referenced), to which nuts  9  and washers  10  are arranged in order to secure the column shoe to the vertical anchor bolt  8  in the base  2 . In  FIG. 37  the column shoe is secured to the steel concrete column  1  by casting the attachment unit  7  to the steel concrete column  1  and by casting the bolt housing  3  partly to the steel concrete column  1 . 
     The column shoes shown in  FIGS. 1 to 37  comprise a bolt housing  3 , the upper structure  6  of which comprises a sleeve structure  12  which is formed integrally with the upper structure  6  and on which the hole  11  for the attachment unit  7  is formed and which upper structure  6  comprises a wall structure  13 , by which the sleeve structure  12  is connected with the baseplate  5  and which wall structure  13  is tapering in direction of the sleeve structure  12 . 
       FIGS. 1 to 28  show four different bolt housings  3  of column shoe, wherein  FIGS. 1 to 7  show a first embodiment of the bolt housing  3  of column shoe,  FIGS. 8  to  14  show a second embodiment of the bolt housing  3  of column shoe,  FIGS. 15 to 21  show a third embodiment of the bolt housing  3  of column shoe, and  FIGS. 22 to 28  show a fourth embodiment of the bolt housing  3  of column shoe. It is in common to all of these embodiments that the wall structure  13  is tapering in direction of the sleeve structure  12 . 
     The bolt housing  3  is fabricated by casting such that the upper structure  6  of the bolt housing  3  and the baseplate  5  form a single-piece casting. The casting is preferably, but not necessarily, fabricated from cast steel or cast iron. The bolt hole  4  of baseplate  5  may be formed in connection with casting or may be at least partly machined after casting. 
     A hole  11  is formed in the bolt housing  3  for the attachment unit  7 . The hole  11  is substantially coaxial with the bolt hole  4  of the baseplate  5 . This results in that, provided a rectilinear attachment unit  7  such as a rectilinear reinforcement bar is used in the column shoe, as shown in  FIGS. 30 to 37 , and provided a rectilinear anchor bolt  8  is used in the base  2  of steel concrete column  1  during mounting, the reinforcement bar and the anchor bolt  8  may be located substantially on the same axis whereupon no eccentricity is formed between the reinforcement bar and the anchor bolt  8 . The hole  11  may be formed in connection with casting or may be at least partly machined after casting. 
     Further holes (not shown in Figures) may be formed in bolt housing  3 , such as in the upper structure  6  of the bolt housing  3 , for further attachment units (not shown in Figures), but more preferably only one hole  11  is formed in the bolt housing  3  for a single attachment unit  7 , which hole  11  is substantially coaxial with the bolt hole  4  of the baseplate  5 , as shown in Figures. 
     The upper structure  6  of the bolt housing  3 , as shown in  FIGS. 1 to 28 , comprises a sleeve structure  12  which is formed integrally with the upper structure  6  and on which the hole  11  for the attachment unit  7  is formed. The upper structure  6  of the bolt housing  3 , as shown in  FIGS. 1 to 28 , comprises a wall structure  13  by which the sleeve structure  12  is connected with the baseplate  5 . 
     The upper structure  6  of the bolt housing  3  is such that it is tapering in direction of the sleeve structure  12 . Such bolt housings  3  are shown in  FIGS. 1 to 28 . 
     In case the upper structure  6  of the bolt housing  3  comprises a wall structure  13 , the wall structure in the upper structure  6  of the bolt housing  3  may be at least partly arcuate in shape so that it is tapering in direction of the sleeve structure  12 . Such bolt housings  3  are shown in  FIGS. 1 to 28 . In case the wall structure  13  in the upper structure  6  of the bolt housing  3  is at least partly arcuate in shape, it may at least partly have a parabolic shape. An advantage of this kind of arcuate, such as parabolic shaped wall structure  13  of upper frame  6  compared to a conventional vertical one is for example that it may better compensate forces and tensions in the bolt housing. 
     In case the upper structure  6  of the bolt housing  3  comprises a wall structure  13 , the wall structure  13  in the upper structure  6  of the bolt housing  3  may be comprised of a plurality of separate wall structure portions  14  by which the sleeve structure  12  is connected with the baseplate  5 .  FIGS. 8 to 14  show a bolt housing  3 , the wall structure  13  of which is comprised of two separate wall structure portions  14 . The wall structure portions  14  may be arranged symmetrically in relation to the bolt hole  4  and the hole  11 . 
     Alternatively the upper structure  6  of the bolt housing  3  may comprise a wall structure  13 , on which a hole  11  is formed for the attachment unit  7 , Then, the wall structure  13  in the upper structure  6  of the bolt housing  3  may be such that it is tapering in direction away from the baseplate  5 . Alternatively, the wall structure  13  in the upper structure  6  of the bolt housing  3  may be at least partly arcuate in shape so that it is tapering in direction away from the baseplate  5 . In case the wall structure  13  in the upper structure  6  of the bolt housing  3  is at least partly arcuate in shape, it may at least partly have a parabolic shape. 
     The bolt housing  3  may consist of a single-piece casting, as shown in  FIGS. 1 to 28 . 
     The attachment unit  7  of column shoe comprises preferably, but not necessarily, a reinforcement bar.  FIGS. 29 to 36  show column shoes, in which one reinforcement bar serves as attachment unit  7 . The reinforcement bar is preferably, but not necessarily, substantially rectilinear. 
     In case the attachment unit  7  is a reinforcement bar, the diameter of the hole  11  is preferably, but not necessarily, such that it substantially corresponds to the diameter of the reinforcement bar. 
     In case the attachment unit  7  is a reinforcement bar, the hole  11  may be provided with inner threads (not shown in Figures) and the reinforcement bar may be provided with outer threads (not shown in Figures) which are adapted to cooperate with the inner threads of the hole  11  so that the reinforcement bar is secured to the bolt housing  3  by screwing the reinforcement bar to the hole  11  of the bolt housing  3 . In case there is one reinforcement bar as attachment unit  7 , the reinforcement bar is preferably, but not necessarily, substantially rectilinear and substantially circular in cross-section so that the reinforcement bar is substantially coaxial with the bolt hole  4  in the baseplate  5  of the bolt housing  5 . 
     The attachment unit  7  may be secured to the bolt housing  3  by pressing the bolt housing  3  into engagement with the attachment unit  7  arranged in hole  11  by pressing the bolt housing  3  at the location of the hole  11 . 
     The attachment unit  7  may be secured to the hole  11  by means of a sleeve (not shown in Figures), which is arranged into the hole  11  and on which the attachment unit  7  is arranged so that for example a crimp connection is formed between the hole  11  and the sleeve and respectively between the sleeve and the attachment unit  7 . 
     Attachment lugs  15 , which protrude from the bolt housing  3 , may be formed by casting to the bolt housing  3 . Such bolt housings  3  are shown in  FIGS. 14 to 28 . Attachment lugs  15  may be provided with holes  18 , as shown in  FIGS. 22 to 28 . Attachment lugs  15  are used for enhancing the fastening of the bolt housing  3  to the steel concrete column  1 . Such attachment lugs  15  also permit to increase the rigidity of the bolt housing  3 . During assembly phase of the column shoe, a wire or a reinforcement bar may be passed through the eventual holes  18  of the attachment lugs  15  in order for example to secure a plurality of column shoes together. 
     Holes  16  may be formed in the edge of the baseplate  5  of the bolt housing  3  for securing at least one hole plate  17 . Hole plates  17  are shown in  FIGS. 33 and 34  and  FIGS. 35 and 36 . Such hole plate  17  permits for example a plurality of column shoes to be secured together or a column shoe to be secured to for example a cast mold or equivalent during mounting, when the column shoe is at least partly cast to the steel concrete column  1 . 
       FIGS. 1 to 7  show a first embodiment of the bolt housing  3  of column shoe. In  FIGS. 1 to 7  the bolt housing  3  comprises a baseplate  5  provided with a bolt hole  4 . To the baseplate  5  is connected an upper structure  6 , on which a hole  11  is formed for the attachment unit  7 . The hole  11  is substantially coaxial with the bolt hole  4  of the baseplate  5 . In  FIGS. 1 to 7  the upper structure  6  a sleeve structure  12  which is formed integrally with the upper structure  6  and on which the hole  11  for the attachment unit  7  is formed. In  FIGS. 1 to 7  the upper structure  6  of the bolt housing  3  comprises a wall structure  13  by which the sleeve structure  12  is connected with the baseplate  5 . In  FIGS. 1 to 7  the wall structure  13  in the upper structure  6  of the bolt housing  3  is at least partly arcuate in shape so that the wall structure  13  in the upper structure  6  of the bolt housing  3  is tapering in direction of the sleeve structure  12 . In  FIGS. 1 to 7  the bolt housing  3  consists of a single-piece casting, 
       FIGS. 8 to 14  show a second embodiment of the bolt housing  3  of column shoe. The bolt housing  3  shown in.  FIGS. 8 to 14  differs from the bolt housing  3  shown in  FIGS. 1 to 7  in that the upper structure  6  of the bolt housing  3  comprises a wall structure  13 , which is comprised of two wall structure portions  14  by which the sleeve structure  12  is connected with the baseplate  5 . 
       FIGS. 15 to 21  show a third embodiment of the bolt housing  3  of column shoe. The bolt housing  3  shown in  FIGS. 15 to 21  differs from the bolt housing  3  shown in  FIGS. 1 to 7  in that two attachment lugs  15 , which protrude from the bolt housing  3 , are formed by casting to the bolt housing  3 . Attachment lugs  15  are used for enhancing the fastening of the bolt housing  3  to the steel concrete column  1 . 
     In  FIGS. 22 to 28  is shown a fourth embodiment of the bolt housing  3  of the column shoe. The bolt housing  3  shown in  FIGS. 22 to 28  differs from the bolt housing  3  shown in  FIGS. 15 to 21  in that two attachment lugs  15  provided with holes  18  are formed by casting to the bolt housing  3 . 
     It is obvious to a person in the art that as technology advances, the inventive concept can be implemented in various ways. Therefore the invention and the embodiments thereof are not limited to the examples shown hereinbefore but may vary within the frames of the claims.