Patent Publication Number: US-11655631-B2

Title: Thermal insulation structure having shear rebars and tension bars integrally formed in thermal insulation unit

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to Korean Patent Application No. 10-2020-0083008 filed in the Korean Intellectual Property Office on Jul. 6, 2020, the disclosure of which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     Embodiments of the disclosure relate to thermal insulation and, more specifically, to a thermal insulation structure or insulator including connection tension rebars passing through a thermal insulation unit and connecting tension bars that are buried in a floor slab and a balcony slab and that have different thermal conductivity from the tension bars, and shear rebars provided in the thermal insulation unit to connect and support the connection tension rebars. 
     DISCUSSION OF RELATED ART 
     In general, a house is defined as a structure that includes a room and walls to separate the inside from the outside. The walls and roof of a house are usually formed of slabs made of cast concrete. 
     A wall of a house is formed by performing various steps, such as rebar assembly, formwork installation, concrete casting, exterior finishing, insulator attachment, and interior finishing. 
     Insulators are used to prevent heat transfer from the inside to outside or vice versa. Insulators are typically attached to the inside (inner walls) or outside (outer walls) of a building, and particularly, it is known that more effective insulation may be achieved when insulators are attached to the outside (outer wall) of the building. 
     However, a protruding structure, e.g., a veranda or balcony, of a building may cause discontinuities in the insulators on the outer wall of the building. 
     Discontinuities in insulation may deteriorate insulation performance. 
     Heat losses may occur through the discontinuities of insulators along the slabs or rebars. This phenomenon is called thermal bridging. 
     In building, it may thus be of significance to prevent thermal bridging. Typically, since 70% to 80% of cool or hot air leak out due to thermal bridging in cooling or heating a building, construction for preventing thermal bridging is required to save cooing/heating costs. 
     Further, thermal bridging may cause condensation on the inner surface of the walls, resulting in mold growth and ill health. 
     Further, as rebars are installed inside the protruding structure, e.g., veranda or balcony, to give reinforced support, more heat losses may occur due to the rebars which have large thermal conductivity. 
     In other words, the veranda or balcony may act as an air fin that accelerates heat leakage. 
     To address such issues, conventional methods install thermal breaks in verandas or balconies. 
     Korean Patent No. 10-1462800 discloses a thermal break using discontinuous rebars, and other various thermal breaks are well known. 
     The thermal break disclosed in Korean Patent No. 10-1462800 is briefly described below. 
     Referring to  FIG.  6   , a thermal break using discontinuous rebars includes an insulator  10 , an upper tension module  20  and lower tension module  20  disposed along the width direction of the insulator  10  to resist tension in the moment direction, a compression module  30  that bears the compressive force of a slab against the vertical load of a balcony, and a truss-type inclined shear rebar  40  connecting the tension modules  20  and the compression module  30 . 
     In the conventional thermal break, however, the truss-shaped inclined shear rebar  40  connects the inside of the wall with an external tension rebar  23  and thus still suffers from thermal bridging in which the internal heat leaks to the outside through the tension rebar  23 . 
     Further, as the shear rebar  40  is coupled to the compression module  30  while passing through the cover of the compression module  30 , the coupling between the shear rebar  40  and the compression module  30  is weak, and the compression module is small in size and fails to provide sufficient compressive force. 
     Although thermal break may be achieved by cutting the shear rebar  40  where the shear bar  40  and the compression module are coupled together, the coupling between the shear rebar and the compression module may weaken, resulting in poor shear force. 
     SUMMARY 
     According to an embodiment, a thermal insulation structure comprises a thermal insulation unit provided between a floor slab and a balcony slab, an upper first tension rebar and a lower first tension rebar buried in the floor slab, an upper second tension rebar and a lower second tension rebar buried in the balcony slab, an upper connection tension rebar passing through the thermal insulation unit and connecting respective opposite ends of the upper first tension rebar and the upper second tension rebar and a lower connection tension rebar passing through the thermal insulation unit and connecting respective opposite ends of the lower first tension rebar and the lower second tension rebar, shear rebars spaced apart from each other in parallel in the thermal insulation unit and connecting the upper connection tension rebar and the lower connection tension rebar, and at least one auxiliary shear rebars provided between the shear rebars and connecting the shear rebars. 
     The at least one auxiliary shear rebars may include at least two auxiliary shear rebars horizontally connecting the shear rebars and vertically spaced apart from each other at a predetermined interval. 
     The at least one auxiliary shear rebars may connect, in an inclined direction, a top of one of the shear rebars with a bottom of another of the shear rebars. 
     The thermal insulation structure may further comprise an upper coupling cover installed on a top surface of the thermal insulation unit and a lower coupling cover installed on a bottom surface of the thermal insulation unit, wherein a bottom surface of the upper coupling cover has a larger width than the top surface of the thermal insulation unit, and a top surface of the lower coupling cover has a larger width than the bottom surface of the thermal insulation unit, and wherein the upper coupling cover and the lower coupling cover are connected to concrete of the floor slab and the balcony slab. 
     Each of the upper coupling cover and the lower coupling cover may have two opposite sides that are inclined so that a width between the two opposite sides increases toward a center of the thermal insulation unit and are connected to the floor slab and the balcony slab. 
     Each of the upper coupling cover and the lower coupling cover may have anti-escape jaws at two opposite ends, and wherein a top and bottom of each of the anti-escape jaws are covered and supported by concrete of the floor slab and the balcony slab. 
     The floor slab, the balcony slab, and the thermal insulation unit may be connected together by the upper connection tension rebar and the lower connection tension rebar. 
     The upper and lower first tension rebars and the upper and lower second tension rebars may be formed of the same material, and the upper and lower connection tension rebars are formed of a different material from the upper and lower first tension rebars. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the disclosure and many of the attendant aspects thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG.  1    is a cross-sectional view illustrating a thermal insulation structure according to an embodiment; 
         FIG.  2    is a perspective view illustrating a thermal insulation structure according to an embodiment; 
         FIG.  3    is a cross-sectional view illustrating a thermal insulation structure further including auxiliary shear rebars in a thermal insulation unit according to an embodiment; 
         FIG.  4    illustrates an example in which a thermal insulation structure includes N-shaped, or inverted N-shaped combinations of shear rebars and auxiliary shear rebars in a thermal insulation unit according to an embodiment; 
         FIG.  5    illustrates a thermal insulation structure further including coupling covers according to an embodiment; and 
         FIG.  6    is a cross-sectional view illustrating a thermal break according to the prior art. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, preferred embodiments of the disclosure are described with reference to the accompanying drawings to be easily practiced by one of ordinary skill in the art. 
       FIG.  1    is a cross-sectional view illustrating a thermal insulation structure according to an embodiment.  FIG.  2    is a perspective view illustrating a thermal insulation structure according to an embodiment.  FIG.  3    is a cross-sectional view illustrating a thermal insulation structure further including auxiliary shear rebars in a thermal insulation unit according to an embodiment.  FIG.  4    illustrates an example in which a thermal insulation structure includes N-shaped, or inverted N-shaped combinations of shear rebars and auxiliary shear rebars in a thermal insulation unit according to an embodiment.  FIG.  5    illustrates a thermal insulation structure further including coupling covers according to an embodiment. 
     Referring to  FIGS.  1  to  4   , a thermal insulation structure  100  includes a thermal insulation unit  110  provided between a floor slab  101  and a balcony slab  102 , an upper first tension rebar and a lower first tension rebar buried in the floor slab  101 , an upper second tension rebar and a lower second tension rebar buried in the balcony slab  102 , an upper connection tension rebar passing through the thermal insulation unit  110  and connecting respective opposite ends of the upper first tension rebar and the upper second tension rebar and a lower connection tension rebar passing through the thermal insulation unit  110  and connecting respective opposite ends of the lower first tension rebar and the lower second tension rebar; shear rebars  150  spaced apart from each other in parallel in the thermal insulation unit  110  and connecting the upper connection tension rebar and the lower connection tension rebar, and at least one auxiliary shear rebars  160  provided between the shear rebars  150  and connecting the shear rebars  150 . 
     Referring to  FIGS.  1  to  5   , the floor slab  101  and the balcony slab  102  are horizontally connected with the thermal insulation unit  110  via connection tension rebars  140 . Upper and lower connection tension rebars  140  pass through the thermal insulation unit  110 , which is an insulator, and the floor slab  101  and balcony slab  102 , which are formed of concrete. By the configuration, there are no other heat transfer elements than the connection tension rebars  140  connected from the floor slab  101  through the thermal insulation unit  110  to the balcony slab  102 , so that the thermal bridge breaking effect may be very high. The plurality of shear rebars  150  installed inside the thermal insulation unit  110  may provide sufficient stability even without other separate shear rebars. 
     Typically, an apartment in an apartment building is composed of wall slabs (not shown) and a floor slab (e.g., the floor slab  101 ) to divide floors. The balcony slab  102  is connected to the floor slab  101  and projects outward of the wall slab. 
     The balcony or veranda sticking out the wall may act as a kind of air fin to cause heat dissipation). The heat from the floor slab  101  may be abruptly transferred to the balcony slab  102 , causing drastic heat (or coldness) losses to the outside. 
     Rebars for connecting the floor slab  101  and the balcony slab  102  may be buried and installed in the floor slab  101  and the balcony slab  102  to provide reinforced support to the balcony slab  102 , in which case such heat losses may be accelerated through the rebars which have high heat conductivity. 
     According to an embodiment, thermal breaks are installed in the slabs of a building to prevent heat (or coldness) losses to the outside. According to an embodiment, the thermal insulation unit  110  is installed at the junction between the floor slab  101  and the balcony slab  102  to break or prevent thermal bridging. 
     Thus, the floor slab  101  and the balcony slab  102  may be prevented from thermal bridging while remaining connected to each other by the thermal insulation unit  110 . However, such a mere structure may weaken connection between the floor slab  101  and the balcony slab  102 . 
     To make up for such weakness and provide reinforced support, upper and lower first tension rebars  120  are installed inside the floor slab  101 , upper and lower second tension rebars  130  are installed inside the balcony slab  102 , and upper connection tension rebars  140  are installed to pass through the thermal insulation unit  110  to connect the respective opposite ends of the upper first tension rebars  120  and the upper second tension rebars  130  and lower connection tension rebars  140  are installed to pass through the thermal insulation unit  110  to connect the respective opposite ends of the lower first tension rebars  120  and the lower second tension rebars  130  to thereby reinforce connection between the floor slab  101  and the balcony slab  102 . Further, the upper and lower connection tension rebars  140  have much lower thermal conductivity than the first tension rebars  120  and the second tension rebars  130  and are vertically welded together, thus decreasing the heat conductance or transfer from the first tension rebars  120  to the second tension rebars  130  and hence preventing or reducing thermal bridges. 
     However, this structure may be relatively weak in shear force as compared with when the first tension rebars  120  and the second tension rebars  130  are directly connected and may be insufficient in ensuring support and shear force between the floor slab  101  and the balcony slab  102 . 
     Rebars (reinforcing bars) are buried in the balcony slab  102  and the floor slab  101 , and the thermal insulation unit  110  is connected to the floor slab  101  and the balcony slab  102 , between the floor slab  101  and the balcony slab  102 . The upper and lower connection tension rebars  140  are formed to pass through the thermal insulation unit  110 , but the tension rebars  120  and  130  do not pass through the thermal insulation unit  110 . The tension rebars  120  and  130  are connected to the connection tension rebars  140 . The connection tension rebars  140  have significantly low thermal conductivity as compared with the tension rebars  120  and  130 . By the structure, thermal bridging which cause heat loss or leakage to the outside may be prevented. 
     The shear rebars  150  may be installed inside the thermal insulation unit  110  to vertically connect the upper and lower connection tension rebars  140  to increase support and shear force. 
     The auxiliary shear rebars  160  may be provided to connect the shear rebars  150  by welding to further reinforce support and shear force. 
     Two or more auxiliary shear rebars  160  may be horizontally installed one over another, at predetermined intervals, between the shear rebars  150  to further reinforce support or shear force as shown in  FIG.  3   . 
     As the shear rebars  150  and the auxiliary shear rebars  160  are integrally formed by welding inside the thermal insulation unit  110 , and the shear rebars  150  are welded to the upper and lower connection tension rebars  140  inside the thermal insulation unit  110 , the upper and lower connection tension rebars  140  may remain constant in interval and position and withstand compressive stress. Thus, even without any separate support for withstanding compressive stress, and the upper and lower connection tension rebars  140  may be prevented from buckling and have enhanced structural stability. 
     Referring to  FIG.  4   , the auxiliary shear rebars  160  may be formed to connect the top end of one shear rebar  150  and the bottom end of the other shear rebar  150 , thus allowing them to overall look like the letter “N” or inverted N. The shear rebars  150  and auxiliary shear rebars  160 , although installed only in the thermal insulation unit  110 , may provide sufficient support and stability. Thus, easy and quick installation or construction is possible. 
     According to an embodiment, the first tension rebars  120  and the second tension rebars  130  may be formed of the same material, and the first tension rebars  120  and the second tension rebars  130  may be formed of a different material from the connection tension rebars  140 , thus simultaneously enhancing thermal bridging breaking effects and stability. For example, the first tension rebars  120  and the second tension rebars  130  may be formed of rebars (made of regular steel), and the connection tension rebars  140 , the shear rebars  150 , and the auxiliary shear rebars  160  may be formed of stainless steel. However, the shear rebars  150  and the auxiliary shear rebars  160  may also be formed of rebars (made of regular steel) even in which case the thermal bridge breaking effect may be maintained. 
     As such, according to an embodiment, in the thermal insulation structure  100 , in which the shear rebars  150  are buried inside the thermal insulation unit  110 , and the shear rebars  150  are integrally formed with the connection tension rebars  140 , the connection tension rebars  140 , which have significantly low thermal conductivity as compared with rebars, are formed to pass through the thermal insulation unit  110  and connected to the rebars provided in the slabs, thereby preventing or reducing thermal bridging, and the shear rebars  150  are vertically provided in parallel with each other to connect the upper and lower connection tension rebars  140 , thereby reinforcing shear force. Further, the auxiliary shear rebars  160  are provided horizontally to connect the shear rebars  150   s , thereby further reinforcing shear force. 
     According to an embodiment, the thermal insulation structure  100 , in which the shear rebars  150  are provided inside the thermal insulation unit  110  and the shear rebars  150  are integrally formed with the connection tension rebars  140 , may further include an upper coupling cover  170  and a lower coupling cover  170  coupled to the top and bottom, respectively, of the thermal insulation unit  110  installed at the junction between the floor slab  101  and the balcony slab  102 , as illustrated in  FIG.  5   . The thermal insulation unit  110  may be formed of an insulator, e.g., expanded polystyrene (EPS). 
     The coupling covers  170  are installed on the top and bottom of the thermal insulation unit  110  to delay or block the upward or downward spread or transfer of flames or high temperatures of the thermal insulation unit  110 , e.g., when a building fire occurs. The coupling covers  170  may be formed of lightweight concrete. The coupling covers  170  may be connected to the concrete of the floor slab  101  and the balcony slab  102 . The top surface of the upper coupling cover  170  may be coplanar or flush with the top surfaces of the floor slab  101  and the balcony slab  102 , and the bottom surface of the lower coupling cover  170  may be coplanar or flush with the bottom surfaces of the floor slab  101  and the balcony slab  102  as illustrated in  FIG.  5   . The top surface of the upper coupling cover  170  may be substantially identical in width to the top surface of the thermal insulation unit  110 , and the bottom surface of the upper coupling cover  170  may be larger in width than the top surface of the thermal insulation unit  110 . The bottom surface of the lower coupling cover  170  may be substantially identical in width to the bottom surface of the thermal insulation unit  110 , and the top surface of the lower coupling cover  170  may be larger in width than the bottom surface of the thermal insulation material. 
     Thus, the coupling covers  170  are supported by the concrete of the floor slab  101  and the balcony slab  102  and may thus be prevented from escaping off. 
     Each of the coupling covers  170  have two opposite sides  171  that are inclined so that the distance thereof increases toward the inside of the floor slab  101  and the balcony slab  102 . The inclined surfaces  171  may prevent the coupling covers  170  from escaping off the floor slab  101  and the balcony slab  102  in case of fire, thus stopping or delaying spread of flames. The thermal insulation unit  110  has excellent thermal insulation performance but may be vulnerable to fire, so that if the coupling covers  170  are removed, flames may spread very quickly. 
     Referring to  FIG.  5 ( b ) , two opposite ends of each coupling cover  170  may have anti-escape jaws  172  positioned inside the floor slab  101  and the balcony slab  102  to prevent the coupling cover  170  from escaping off. 
     Thus, the thermal insulation structure  100 , in which the shear rebars  150  are provided in the thermal insulation unit  110 , and the shear rebars  150  and the connection tension rebars  140  are integrally formed, may at least partially stop or delay flame spread by the coupling covers  170  provided in the thermal insulation unit  110 . 
     According to the embodiments of the disclosure, by the configuration described above, heat loss that may be caused by the first and second tension rebars may be prevented by the connection tension rebars which have different thermal conductivity from the first and second tension rebars. Thus, thermal bridging or heat losses may be effectively prevented or reduced. 
     Further, as the upper and lower connection tension rebars are connected by the shear rebars vertically positioned between the upper and lower connection tension rebars, deformation or buckling due to compression stress may be prevented, and allowable spreading factor for the slabs may be increased. 
     The coupling covers are formed on the top and bottom of the thermal insulation unit, and the coupling covers have inclined side surfaces or anti-escape jaws which are connected to, or buried or covered by the concrete of the floor slab and the balcony slab so that the coupling covers may be prevented from escaping off in case of fire while preventing spread of flames. 
     The auxiliary shear rebars are provided between the shear rebars, which are formed vertically and in parallel with each other, to connect the shear rebars horizontally or inclinedly, thereby providing enhanced shear force and support. 
     In the thermal insulation structure, the tension rebars and shear rebars are integrally formed, with the shear rebars excluded from the heat pathway, thereby increasing thermal insulation. 
     The upper and lower connection tension rebars are connected and supported by the vertical shear rebars in the thermal insulation unit, thus remaining constant in interval and position while withstanding compression stress. Thus, the upper and lower connection tension rebars may be prevented from buckling even without a separate supporting structure. As such, the thermal insulation structure may have enhanced structural stability. 
     Although the disclosure is shown and described with reference to embodiments thereof, it would be appreciated by one of ordinary skill in the art that various changes or modifications may be made thereto without departing from the scope of the disclosure defined by the claims.