Doughtnut-shaped hollow core body, bidirectional hollow core slab using the same, and construction method thereof

Abstract

The present invention relates to a lightweight bidirectional hollow core slab, and a doughnut-shaped hollow core body which may be advantageously used in the construction of a bidirectional hollow core slab. The doughnut-shaped hollow core body according to the present invention includes an outer case formed in a generally doughnut shape, wherein a hollow portion with a circular section is formed in the center thereof and corners are rounded with curved surfaces. The bidirectional hollow core slab according to the present invention is made by stably locating the doughnut-shaped hollow core bodies in concrete in such a manner that the doughnut-shaped hollow core body is restrained and mounted in steel bar cages or on the upper and lower steel bars.

1 . A hollow core body  100 , which is adapted to be buried into concrete for the construction of a lightweight concrete member, having a hollow portion  110  with a circular section formed in the center thereof and corners rounded with curved surfaces, thereby providing a generally doughnut-shaped outer case. 
     
     
         2 . The hollow core body as defined in  claim 1 , wherein a cavity area  120  is formed in the doughnut-shaped outer case. 
     
     
         3 . The hollow core body as defined in  claim 2 , wherein the cavity area  120  is filled with an insulation material or a vibration-proof material. 
     
     
         4 . The hollow core body as defined in  claim 2 , wherein two or more constitution parts  100   a  and  100   b  are coupled to each other to form the hollow core body  100 , each of the constitution parts  100   a  and  100   b  being made of any one of reinforced plastic into which glass fiber is mixed, biodegradable plastic, and biomass plastic. 
     
     
         5 . The hollow core body as defined in  claim 1 , wherein a height H of the hollow core body  100  is in a range between 120 mm and 150 mm, lengths L 1  and L 2  thereof in a range between 90 mm and 270 mm, and a diameter D of the hollow portion  110  thereof in a range between 15 mm and 45 mm. 
     
     
         6 . A bidirectional hollow core slab comprising:
 steel bar cages  200  made by coupling steel bars;   doughnut-shaped hollow core bodies  100  spacedly arranged in rows and columns in such a manner as to be restrained in the steel bar cages  200 ;   slab lower steel bars  411  and  412  crossedly arranged as main bars and distributing bars beneath the steel bar cages  200 ;   slab upper steel bars  413  and  414  crossedly arranged as main bars and distributing bars on the steel bar cages  200 ; and   slab concrete  420  cast and cured to a thickness through which the slab lower and upper steel bars  411 ,  412 ,  413  and  414  are buried,   wherein each steel bar cage  200  comprises: a first side bent bar  210  bent and divided into a first inclined portion  211  and first horizontal portions  212  formed on both sides of the first inclined portion  211 , the first side bent bar  210  being inclinedly erected to form the first side thereof; a second side bent bar  220  bent and divided into a second inclined portion  221  and second horizontal portions  222  formed on both sides of the second inclined portion  221 , the second side bent bar  220  being inclinedly erected toward the first side bent bar  210  in such a manner as to face the first side bent bar  210 , thereby forming the second side thereof, and the second inclined portion  221  being located in a direction crossing the first inclined portion  211  of the first side bent bar  210 ; an upper bent bar  230  bent and divided into a third inclined portion  231  and third horizontal portions  232  formed on both sides of the third inclined portion  231 , the upper bent bar  230  being horizontally located on the upper portion between the first and second side bent bars  210  and  220  facing each other, thereby forming the upper side thereof, and the third horizontal portions  232  being connected to the first and second horizontal portions  212  and  222  of the first and second side bent bars  210  and  220 ; a first end tilt bar  241  located to inclinedly connect the first horizontal portion  212  on one end of the first side bent bar  12101  to the second horizontal portion  222  on one end of the second side bent bar  220 ; and a second end tilt bar  242  located to inclinedly connect the first horizontal portion  212  on the other end of the first side bent bar  210  to the second horizontal portion  222  on the other end of the second side bent bar  220 , and   each doughnut-shaped hollow core body  100  comprises fitting slots  140   a  formed correspondingly on both sides facing each other, into which the first and second inclined portions  211  and  221  of the first and second side bent bars  210  and  220  are insertedly fitted, so that the hollow core bodies  100  are inserted into the steel bar cages  200  and the first and second inclined portions  211  and  221  of the first and second side bent bars  210  and  220  are insertedly fitted to the fitting slots  140   a , thereby being restrained into the steel bar cages  200 .   
     
     
         7 . The bidirectional hollow core slab as defined in  claim 6 , wherein the first and second side bent bars  210  and  220  and the upper bent bar  230  of each steel bar cage  200  are continuously bent to a trapezoidal shape to provide two or more first, second and third inclined portions  211 ,  221  and  231 , thereby forming the first, second and third horizontal portions  212 ,  222  and  232  at both ends of the respective inclined portions, and each steel bar cage  200  has the plurality of doughnut-shaped hollow core bodies  100  restrainedly inserted thereinto. 
     
     
         8 . A bidirectional hollow core slab comprising:
 steel bar cages  200  made by coupling steel bars;   doughnut-shaped hollow core bodies  100  spacedly arranged in rows and columns in such a manner as to be restrained in the steel bar cages  200 ;   slab lower steel bars  411  arranged as main bars beneath the steel bar cages  200 ;   slab upper steel bars  414  arranged as main bars on the steel bar cages  200  in a direction parallel to the slab lower steel bars  411 ; and   slab concrete  420  cast and cured to a thickness through which the slab lower and upper steel bars  411  and  414  are buried,   wherein each steel bar cage  200  comprises: first and second lower horizontal bars  251  and  252  spaced apart from each other in parallel with each other; first and second upper horizontal bars  253  and  254  spaced apart from each other with a width smaller than the first and second lower horizontal bars  251  and  252  above the first and second lower horizontal bars  251  and  252 ; a first side tilt bars  261  adapted to connect the first upper and lower horizontal bars  251  and  253  to each other, while being inclined to each other along the lengthwise directions of the first upper and lower horizontal bars  251  and  253  in such a manner where the inclined directions of the neighboring first side tilt bars  261  are opposite to each other; second side tilt bars  262  adapted to connect the second upper and lower horizontal bars  252  and  254  to each other, while being inclined to each other along the lengthwise directions of the second upper and lower horizontal bars  252  and  254  in such a manner where the inclined directions of the second side tilt bars  262  are opposite to those of those of the first side tilt bars  261  in such a manner as to cross the first side tilt bars  261 ; upper tilt bars  263  adapted to connect the first and second upper horizontal bars  253  and  254  to each other, while being inclined to each other along the lengthwise directions of the first and second upper horizontal bars  253  and  254  in such a manner as to connect the first and second side tilt bars  261  and  262  facing each other; a first end tilt bar  241  adapted to inclinedly connect one end portion of the first upper horizontal bar  253  and one end portion of the second lower horizontal bar  252 ; and a second end tilt bar  242  adapted to inclinedly connect the other end portion of the first upper horizontal bar  253  and the other end portion of the second lower horizontal bar  252  or to inclinedly connect the other end portion of the second upper horizontal bar  254  and the other end portion of the first lower horizontal bar  251 , and   each doughnut-shaped hollow core body  100  comprises fitting slots  140   a  formed correspondingly on both sides facing each other, into which the first and second side tilt bars  261  and  262  are insertedly fitted, so that the hollow core bodies  100  are inserted into the steel bar cages  200  and the first and second side tilt bars  261  and  262  are insertedly fitted to the fitting slots  140   a , thereby being restrained into the steel bar cages  200 .   
     
     
         9 . The bidirectional hollow core slab as defined in  claim 6 , wherein the fitting slots  140   a  of each doughnut-shaped hollow core body  100  are formed in a shape of X corresponding to the arrangements of the first and second inclined portions  211  and  221  of the first and second side bent bars  210  and  220  or corresponding to the arrangement of the first and second side tilt bars  261  and  262 . 
     
     
         10 . A bidirectional hollow core slab comprising:
 doughnut-shaped hollow core bodies  100  spacedly arranged in rows and columns;   slab lower steel bars  411  and  412  arranged as main bars and distributing bars beneath the doughnut-shaped hollow core bodies  100 ;   slab upper steel bars  413  and  414  arranged as main bars and distributing bars on the doughnut-shaped hollow core bodies  100 ;   steel bar spacers  300  disposed between the doughnut-shaped hollow core bodies  100  and the distributing bars  412  and  413  of the slab lower and upper steel bars; and   slab concrete  420  cast and cured to a thickness through which the slab lower and upper steel bars  411 ,  412 ,  413  and  414  are buried,   wherein each steel bar spacer  300  comprises: a steel bar coupling piece  310  formed to be welded or fitted to the distributing bars  412  and  413 ; and a protrusion  320  formed to be fitted to each doughnut-shaped hollow core body  100 , and   each doughnut-shaped hollow core body  100  comprises fitting slots  140   b  and  140   c  formed on the top and underside surfaces facing each other, so that the protrusions  320  of the steel bar spacers  300  are fitted to the fitting slots  140   b  and  140   c , thereby being restrained into the distributing bars  412  and  413 .   
     
     
         11 . A construction method of a bidirectional hollow core slab as defined in  claim 6 , comprising the steps of:
 crossedly arranging main bars  411  and distributing bars  412  as slab lower steel bars;   disposing steel bar cages  200  into which doughnut-shaped hollow core bodies  100  are restrained on the main bars  411  of the slab lower steel bars;   crossedly arranging distributing bars  413  and main bars  414  as slab upper steel bars on the steel bar cages  200 ; and   casting and curing slab concrete  420  onto the slab lower and upper steel bars.   
     
     
         12 . A construction method of a bidirectional hollow core slab as defined in  claim 8 , comprising the steps of:
 crossedly arranging main bars  411  as slab lower steel bars;   disposing steel bar cages  200  into which doughnut-shaped hollow core bodies  100  are restrained on the main bars  411  of the slab lower steel bars, while first and second lower horizontal bars  251  and  252  of the steel bar cages  200  are being arranged to cross the main bars  411  of the slab lower steel bars;   arranging main bars  414  as slab upper steel bars on the steel bar cages  200 , while the main bars  414  of the slab upper steel bars are being arranged to cross first and second upper horizontal bars  253  and  254  of the steel bar cages  200 ; and   casting and curing slab concrete  420  onto the slab lower and upper steel bars.   
     
     
         13 . The hollow core body as defined in  claim 2 , wherein a height H of the hollow core body ( 100 ) is in a range between 120 mm and 150 mm, lengths L 1  and L 2  thereof in a range between 90 mm and 270 mm, and a diameter D of the hollow portion ( 110 ) thereof in a range between 15 mm and 45 mm. 
     
     
         14 . The hollow core body as defined in  claim 3 , wherein a height H of the hollow core body ( 100 ) is in a range between 120 mm and 150 mm, lengths L 1  and L 2  thereof in a range between 90 mm and 270 mm, and a diameter D of the hollow portion ( 110 ) thereof in a range between 15 mm and 45 mm. 
     
     
         15 . The hollow core body as defined in  claim 4 , wherein a height H of the hollow core body ( 100 ) is in a range between 120 mm and 150 mm, lengths L 1  and L 2  thereof in a range between 90 mm and 270 mm, and a diameter D of the hollow portion ( 110 ) thereof in a range between 15 mm and 45 mm. 
     
     
         16 . The bidirectional hollow core slab as defined in  claim 7 , wherein the fitting slots ( 140   a ) of each doughnut-shaped hollow core body ( 100 ) are formed in a shape of X corresponding to the arrangements of the first and second inclined portions ( 211 ) and ( 221 ) of the first and second side bent bars ( 210 ) and ( 220 ) or corresponding to the arrangement of the first and second side tilt bars ( 261 ) and ( 262 ). 
     
     
         17 . The bidirectional hollow core slab as defined in  claim 8 , wherein the fitting slots ( 140   a ) of each doughnut-shaped hollow core body ( 100 ) are formed in a shape of X corresponding to the arrangements of the first and second inclined portions ( 211 ) and ( 221 ) of the first and second side bent bars ( 210 ) and ( 220 ) or corresponding to the arrangement of the first and second side tilt bars ( 261 ) and ( 262 ). 
     
     
         18 . A construction method of a bidirectional hollow core slab as defined in  claim 7 , comprising the steps of:
 crossedly arranging main bars ( 411 ) and distributing bars ( 412  as slab lower steel bars;   disposing steel bar cages ( 200 ) into which doughnut-shaped hollow core bodies ( 100 ) are restrained on the main bars ( 411 ) of the slab lower steel bars;   crossedly arranging distributing bars ( 413 ) and main bars ( 414 ) as slab upper steel bars on the steel bar cages ( 200 ); and   casting and curing slab concrete ( 420 ) onto the slab lower and upper steel bars.