Modular Column System Using Internally Confined Hollow Column Unit and Method of Constructing the Same

Abstract

A modular column system and a method of constructing the same are constructed by stacking at least one precast unit between a foundation section and a coping section. The precast unit makes use of an internally confined hollow column unit fabricated in advance, and joint sections between the precast units are firmly formed. Thereby, the modular column system can realize a short construction period and economy because reinforcement bars and forms are not used, as well as high resistance to bending moment and reduction in cross section and self-weight of the precast unit, and thus the modular column system can provide easier and more economical assembly, and prevent brittle fracture of the joint section between the precast units.

1 . A modular column system using at least one internally confined hollow column unit, comprising:
 at least one precast unit installed between a foundation section and a coping section; and   means for fastening the precast unit to the foundation section, fastening the precast units to each other, and fastening the coping section to the precast unit,   wherein the precast unit is the internally confined hollow column unit and includes an outer pipe section formed of steel or fiber reinforced plastic (FRP), a concrete section filled with concrete while forming a hollow section inside the outer pipe section, and an inner pipe section installed in the hollow section of the concrete section and formed of steel or FRP confining the concrete section.   
   
   
       2 . The modular column system as set forth in  claim 1 , wherein the inner pipe section includes a cylindrical pipe. 
   
   
       3 . The modular column system as set forth in  claim 1 , wherein the inner pipe section includes a corrugated pipe which is alternately convex and concave. 
   
   
       4 . The modular column system as set forth in  claim 1 , wherein at least one of the outer pipe section and the inner pipe section has a plurality of shear connectors attached to at least one of opposite surfaces of the outer pipe section and the inner pipe section, the plurality of shear connectors securing unified behavior of at least one of the outer and inner pipe sections with the concrete section. 
   
   
       5 . The modular column system as set forth in  claim 4 , wherein each of the shear connectors includes:
 a stiffener portion that is attached in a plate shape in an axial direction of the unit and functions to resist the buckling of the unit; and   a stud portion that is integrally formed with the stiffener portion, is attached in a plate shape in a radial direction of the unit, and secures unified behavior of the inner and outer pipe sections with the concrete section.   
   
   
       6 . The modular column system as set forth in  claim 1 , wherein:
 the means for fastening the foundation section and the internally confined hollow column unit includes a plurality of foundation section anchoring holes that are formed in an upper portion of the foundation section, a plurality of lower anchoring holes that are formed in a lower portion of the concrete section and are opposite the foundation section anchoring holes, a plurality of bar-like members that are inserted between the lower anchoring holes and the foundation section anchoring holes, and grout that fixes the bar-like members; and   the means for fastening the coping section and the internally confined hollow column unit includes a plurality of coping section anchoring holes that are formed in a lower portion of the coping section, a plurality of upper anchoring holes that are formed in an upper portion of the concrete section and are opposite the coping section anchoring holes, a plurality of bar-like members that are inserted between the upper anchoring holes and the coping section anchoring holes, and grout that fixes the bar-like members.   
   
   
       7 . The modular column system as set forth in  claim 1 , wherein:
 the means for fastening the foundation section and the internally confined hollow column unit includes a lower outer flange that is attached to a lower outer circumference of the internally confined hollow column unit and is provided with a plurality of lower outer fastening holes, and a plurality of fasteners that pass through the lower outer fastening holes, are inserted into a plurality of foundation section outer fastening holes at an upper portion of the foundation section, and fasten the lower outer flange to the foundation section; and   the means for fastening the coping section and the internally confined hollow column unit includes an upper outer flange that is attached to an upper outer circumference of the internally confined hollow column unit and is provided with a plurality of upper outer fastening holes, and a plurality of fasteners that pass through the upper outer fastening holes, are inserted into a plurality of coping section outer fastening holes at a lower portion of the coping section, and fasten the upper outer flange to the coping section.   
   
   
       8 . The modular column system as set forth in  claim 1 , wherein:
 the means for fastening the foundation section and the internally confined hollow column unit includes a lower inner flange that is attached to a lower inner circumference of the inner pipe section of the internally confined hollow column unit and is provided with a plurality of lower inner fastening holes, and a plurality of fasteners that pass through the lower inner fastening holes, are inserted into a plurality of foundation section inner fastening holes at an upper portion of the foundation section, and fasten the lower inner flange to the foundation section; and   the means for fastening the coping section and the internally confined hollow column unit includes an upper inner flange that is attached to an upper inner circumference of the internally confined hollow column unit and is provided with a plurality of upper inner fastening holes, and a plurality of fasteners that pass through the upper inner fastening holes, are inserted into a plurality of coping section inner fastening holes at a lower portion of the coping section, and fasten the upper inner flange to the coping section.   
   
   
       9 . The modular column system as set forth in  claim 1 , wherein the means for mutually fastening the internally confined hollow column units includes a plurality of upper anchoring holes that are formed in an upper portion of a lower one of the internally confined hollow column units, a plurality of lower anchoring holes that are formed in a lower portion of an upper one of the internally confined hollow column units and are opposite the upper anchoring holes, a plurality of bar-like members that are inserted between the upper anchoring holes and the lower anchoring holes, and grout that fixes the bar-like members. 
   
   
       10 . The modular column system as set forth in  claim 1 , wherein the means for mutually fastening the internally confined hollow column units includes an upper outer flange that is attached to an upper outer circumference of a lower one of the internally confined hollow column units and is provided with a plurality of upper outer fastening holes, a lower outer flange that is attached to a lower outer circumference of an upper one of the internally confined hollow column units and is provided with a plurality of lower outer fastening holes opposite the plurality of upper outer fastening holes, and a plurality of fastener tools that pass through the upper and lower outer fastening holes and fasten the upper and lower outer flanges to each other. 
   
   
       11 . The modular column system as set forth in  claim 1 , wherein the means for mutually fastening the internally confined hollow column units includes an upper inner flange that is attached to an upper inner circumference of a lower one of the internally confined hollow column units and is provided with a plurality of upper inner fastening holes, a lower inner flange that is attached to a lower inner circumference of an upper one of the internally confined hollow column units and is provided with a plurality of lower inner fastening holes opposite the plurality of upper inner fastening holes, and a plurality of fastener tools that pass through the upper and lower inner fastening holes and fasten the upper and lower inner flanges to each other. 
   
   
       12 . The modular column system as set forth in  claim 1 , wherein the means for mutually fastening the internally confined hollow column units includes an outer support that has a strip shape and is attached to an outer circumference of a joint section between the internally confined hollow column units placed one after another. 
   
   
       13 . The modular column system as set forth in  claim 1 , wherein the means for mutually fastening the internally confined hollow column units includes an inner support that has a strip shape and is attached to an inner circumference of a joint section between the internally confined hollow column units placed one after another. 
   
   
       14 . A method of constructing a modular column system using at least one internally confined hollow column unit, in which the modular column system includes at least one precast unit installed between a foundation section and a coping section, and means for fastening the precast unit to the foundation section, fastening the precast units to each other, and fastening the coping section to the precast unit, the method comprising the steps of:
 constructing the foundation section so as to form a plurality of foundation section anchoring holes after pit excavation work (S 1 );   injecting grout into the foundation section anchoring holes (S 2 );   inserting bar-like members, which have been inserted into and attached in lower anchoring holes of the internally confined hollow column unit to be placed on an upper portion of the foundation section, into the foundation section anchoring holes, into which the grout has been injected, and attaching the internally confined hollow column unit to the foundation section (S 3 );   injecting the grout into upper anchoring holes of the internally confined hollow column unit (S 4 );   inserting the bar-like members, which have been inserted into and attached in the lower anchoring holes of the internally confined hollow column unit to be placed on the adjacent internally confined hollow column unit, into the upper anchoring holes of the internally confined hollow column unit, into which the grout has been injected, and attaching the internally confined hollow column units to each other (S 5 );   stacking and attaching the internally confined hollow column units by means of repetition of fourth and fifth steps S 4  and S 5  (S 6 );   injecting the grout into the upper anchoring holes of an uppermost one of the internally confined hollow column unit, placed at a sixth step S 6  (S 7 ); and   inserting the bar-like members, which have been inserted into and attached in coping section anchoring holes of a lower portion of the coping section, into the upper anchoring holes, into which the grout has been injected before the grout in the upper anchoring holes is cured in a seventh step S 7 , and attaching the uppermost internally confined hollow column unit to the coping section (S 8 ).