Patent Publication Number: US-2022220720-A1

Title: Beam-column joint structure

Description:
FIELD OF THE INVENTION 
     The instant disclosure relates to a beam-column joint structure, in particular to a beam-column joint structure for a precast concrete column and steel beams. 
     BACKGROUND 
     Conventional methods of constructing reinforced concrete (RC) buildings are conducted floor-by-floor from bottom to top, which is time consuming. Such conventional method involves many processes, such as tying the reinforced steel bars, molding, grouting and so on, which requires a great number of workers on the construction site. Thus, the quality of construction is highly dependent on factors such as weather and the skill and experience of the workers, and is difficult to control. 
     Using steel reinforced concrete (SRC) for load-bearing beams and columns may expedite the construction process. However, extensive use of SRC will require a great amount of steel, resulting in high construction costs. 
     To resolve the above problems, a composite construction including precast RC columns and steel beams is provided. For example, precast RC columns are first fabricated in the factory, and then transported to the construction site to be hoisted and assembled with steel beams. 
     However, some foundations for such conventional constructions are irregular in shape, making it impossible to align the central lines of the beams with the center lines of the precast RC columns located near the boundaries of the irregular foundations. Installation of such eccentric steel beams onto precast RC columns is difficult and time-consuming. Therefore, it is desirable to provide a beam-column joint structure that can be used for rapidly assembling a precast RC column with such eccentric steel beams. 
     SUMMARY OF THE INVENTION 
     According to one exemplary embodiment of the instant disclosure, a beam-column joint structure is provided which comprises: a hollow rectangular steel frame and a plurality of H-beams. The hollow rectangular steel frame consists of a first sidewall, a second sidewall, a third sidewall and a fourth sidewall, wherein the first sidewall is arranged opposed to the third sidewall, and the second sidewall is arranged opposed to the fourth sidewall. Each of the plurality of H-beams is fixedly attached to an outer surface of at least some of the first sidewall, the second sidewall, the third side wall and the fourth sidewall. A first axis is defined by the central position of the first sidewall and the central position of the third sidewall, and a second axis is defined by the central position of the second sidewall and the central position of the fourth sidewall. 
     For further understanding of the instant disclosure, the following embodiments are provided along with illustrations to facilitate appreciation of the instant disclosure; however, the appended drawings are merely provided for reference and illustration and are not intended to be used for limiting the scope of the instant disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aforementioned illustrations and following detailed descriptions are exemplary for the purpose of further explaining the scope of the instant disclosure. Other objectives and advantages related to the instant disclosure will be illustrated in the subsequent descriptions and appended drawings. 
         FIG. 1A  is a perspective schematic view showing a beam-column joint structure in accordance with an embodiment of the instant disclosure; 
         FIG. 1B  is a perspective schematic view showing a beam-column joint structure in accordance with another embodiment of the instant disclosure; 
         FIG. 2  is a perspective schematic view showing a beam-column joint structure in accordance with a further embodiment of the instant disclosure; 
         FIG. 3  is a perspective schematic view showing a precast RC column with connecting rebars extending from its top in accordance with the further embodiment of the instant disclosure; 
         FIG. 4  is a schematic view showing the beam-column joint structure to be connected with the precast RC column in accordance with the further embodiment of the instant disclosure; 
         FIG. 5  is a perspective schematic view showing the beam-column joint structure connected with the precast RC column in accordance with the further embodiment of the instant disclosure; 
         FIG. 6  is another perspective schematic view showing the beam-column joint structure connected with the precast RC column in accordance with the further embodiment of the instant disclosure; 
         FIG. 7  is a schematic view showing the beam-column joint structure connected with the precast RC column with concrete covering the stirrups of the beam-column joint structure and those on the top of precast RC column in accordance with the further embodiment of the instant disclosure. 
         FIG. 8  is a schematic view showing a beam-column joint structure in accordance with a still further embodiment of the instant disclosure; 
         FIG. 9  is a schematic view showing a beam-column joint structure in accordance with a still further embodiment of the instant disclosure; 
         FIG. 10  is a schematic view showing the beam-column joint structure in  FIG. 9  to be assembled with the precast RC column in  FIG. 3 . 
         FIG. 11  is another schematic view showing the beam-column joint structure in  FIG. 9  to be assembled with the precast RC column in  FIG. 3 . 
         FIG. 12  is a schematic view showing the beam-column joint structure in  FIG. 9  assembled with the precast RC column in  FIG. 3  with concrete covering the stirrups of the beam-column joint structure and those on the top of precast RC column. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In order to facilitate understanding of the technical features, technical contents, technical advantages and technical effects of the subject invention, a detailed description with accompanying drawings is provided below for explanation only. The drawings only serve an auxiliary purpose for understanding of the technical contents; the scope of the subject invention should not be interpreted merely based on the scale or the relative positions between the elements illustrated in the drawings. 
     The terminology used in the description of the present disclosure herein is for the purpose of describing particular embodiments only, and is not intended to be construed as a limitation of the invention. As used in the description of the invention and the appended claims, the singular articles “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     As shown in  FIG. 1A , a beam-column joint structure  1  is provided which comprises: a hollow rectangular steel frame  10 , and a plurality of H-beams  21 ,  22 ,  23 ,  24 . The hollow rectangular steel frame  10  consists of a first sidewall  11 , a second sidewall  12 , a third sidewall  13 , and a fourth sidewall  141 , wherein the first sidewall  11  is arranged opposed to the third sidewall  13 , and the second sidewall  12  is arranged opposed to the fourth sidewall  14 . Each of the plurality of H-beams  21 ,  22 ,  23 ,  24  is fixedly attached to an outer surface of at least some of the first sidewall  11 , the second sidewall  12 , the third side wall  13  and the fourth sidewall  14 . A first axis X 1  is defined by the central position of the first sidewall  11  and the central position of the third sidewall  13 , and a second axis X 2  is defined by the central position of the second sidewall  12  and the central position of the fourth sidewall  14 . 
     Each of the plurality of H-beams  21 ,  22 ,  23 ,  24  is composed of a top flange A 1 , a bottom flange A 2  and a web A 3 . In the embodiment as shown in  FIG. 1A , each of the central axes along the lengthwise direction of the plurality of H-beams  21 ,  22 ,  23 ,  24  is aligned with the first axis X 1  or the second axis X 2  of the hollow rectangular steel frame  10 . Consequently, H-beam  21  and H-beam  23  are symmetrically disposed with respect to the hollow rectangular steel frame  10 , and H-beam  22  and H-beam  24  are symmetrically disposed with respect to the hollow rectangular steel frame  10 . 
     In other embodiments of the instant disclosure, the central axis of an H-beam is not necessarily aligned with the first axis X 1  or the second axis X 2  of the hollow rectangular steel frame  10 . For example,  FIG. 1B  illustrates another embodiment of the instant disclosure wherein each of the central axes along the lengthwise direction of the plurality of H-beams  21 ,  22 ,  23 ,  24  is not aligned with the first axis X 1  or the second axis X 2  of the hollow rectangular steel frame  10 . Specifically, the central axis of H-beam  21  and that of H-beam  23  are offset from the first axis X 1  in the transverse direction of the first sidewall  11  or the third sidewall  13 . The central axis of H-beam  22  and that of H-beam  24  are offset from the second axis X 2  in the transverse direction of the second sidewall  12  or the fourth sidewall  14 . In addition, the distance D 1  from the edge of the top flange A 1  or the edge of the bottom flange A 2  to an edge of the first sidewall  11  is more than 10 centimeters. 
     Based on the space provided for the construction and the required strength for the beam-column joint structure  1 , an architect may decide whether the central axis of each H-beam should be aligned with the first axis X 1  or the second axis X 2  of the hollow rectangular steel frame  10 , and if not, the architect needs to decide the offset distance between the central axes and the first axis X 1  or the second axis X 2  of the hollow rectangular steel frame  10 . 
     In the embodiments shown in  FIGS. 1A and 1B , the beam-column joint structure  1  comprises a first steel plate  15  fixed in and near the top of the hollow rectangular steel frame  10  and a second steel plate  16  fixed in and near the bottom of the hollow rectangular steel frame  10 . The first steel plate  15  and the second steel plate  16  have openings  17  in their centers wherein each of the first steel plate  15  and the second steel plate  16  has notches  18  at four corners thereof. In operation, concrete is grouted into the hollow rectangular steel frame  10  through the opening  17  of the first steel plate  15  and concrete may be filled between the beam-column joint structure  1  and the precast RC column  4  (see  FIGS. 5-7 ) through the opening  17  of second steel plate  16 . The notches  18  of the first steel plate  15  and the second steel plate  16  are for air to be expelled out of the hollow rectangular steel frame  10  when concrete is grouted into the hollow rectangular steel frame  10  through the opening  17  of the first steel plate  15  so that the concrete would contain less air when the concrete reaches its final set. 
     In another embodiment of the instant disclosure, some of the outer surfaces of the sidewalls of the hollow rectangular steel frame  10  are provided with H-beams whereas the others are not. As shown in  FIG. 2 , the first sidewall  11  of the hollow rectangular steel frame  10  is not provided with an H-beam, whereas each of the second sidewall  12 , the third sidewall  13  and the fourth sidewall  14  is provided with one H-beam  22 ,  23 ,  24 . In addition, the central axes along the lengthwise direction of the plurality of H-beams  22 ,  23 ,  24  are not aligned with the first axis X 1  or the second axis X 2  of the hollow rectangular steel frame  10 . That is, the H-beams in the embodiment of  FIG. 2  are asymmetrical with respect to the hollow rectangular steel frame  10 . 
       FIGS. 4-7  are schematic views showing the processes that the beam-column joint structure  1  shown in  FIG. 2  is assembled with the precast RC column shown in  FIG. 3  and then the assembled structure is covered with concrete. As shown in  FIG. 2 , each of the three H-beams  22 ,  23 ,  24  contains a column of holes H 1  in the webs A 3  of the H-beams  22 ,  23 ,  24 . The column of holes H 1  is disposed along the heights of the webs A 3  of the H-beams  22 ,  23 ,  24 . A first main spiral stirrup  31  passes through the webs A 3  of the H-beams  22 ,  23 ,  24  via the columns of the holes H 1  and is disposed between the top flanges A 1  and the bottom flanges A 2  of the plurality of H-beams  22 ,  23 ,  24 . Four first auxiliary spiral stirrups  32  are disposed at the circumferences of the first main spiral stirrup  31  and overlap a portion of the first main spiral stirrup  31 . The hollow rectangular steel frame  10  is disposed within the first main spiral stirrup  31  and the four first auxiliary spiral stirrups  32  are located near the four outer corners of the hollow rectangular steel frame  10 . 
     Please refer to  FIG. 3 . The precast RC column  4  comprises a precast body  41  with connecting rebars  43  extending from its top surface  42 . These connecting rebars  43  are generally distributed near the circumference of the top surface  42  and form a space S therein. The size of the space S should be sufficient for accommodating an end of the hollow rectangular steel frame  10  as shown in  FIG. 2 . Furthermore, a second main spiral stirrup  44  is provided to surround some of the connecting rebars  43 ; four second auxiliary spiral stirrups  45  are provided near the four top corners of the precast body  41  and surround the connecting rebars  43  provided at the four top corners of the precast body  41 . The four second auxiliary spiral stirrups  45  overlap several portions of the second main spiral stirrup  44  and thereby some connecting rebars  43  are surrounded by both the second main spiral stirrup  44  and the four second auxiliary spiral stirrups  45 . Each of the second main spiral stirrup  44  and the four second auxiliary spiral stirrups  45  in  FIG. 3  has three coils. In other embodiments, each of the second main spiral stirrup  44  and the four second auxiliary spiral stirrups  45  has a different number of coils. The actual number of coils would depend on the actual design requirements. 
     As shown in  FIG. 3 , for some of those connecting rebars  43  that will be inserted into the bottom flanges A 2  of the H-beams  22 ,  23 ,  24  when the beam-column joint structure  1  is to be assembled with the precast RC column  4 , adjusters  46  are sleeved on these connecting rebars  43  beforehand. These adjusters  46  on the connecting rebars  43  are moveable along the lengthwise direction of the connecting rebars  43  and are arranged to abut against the bottoms of the bottom flanges of the H-beams  22 ,  23 ,  24  for adjusting the levels of the H-beams  22 ,  23 ,  24 . These adjusters  46  in  FIG. 3  are ring-shaped. 
     Please refer to  FIG. 4 , which shows the beam-column joint structure  1  is about to be connected with the precast RC column  4 . The adjusters  46  on the connecting rebars  43  are moved along the connecting rebars  43  to the predetermined heights. The beam-column joint structure  1  is hoisted by a hoister (not shown) above the precast RC column  4  so that the holes H 2  in the bottom flanges A 2  of the H-beams  22 ,  23 ,  24  are aligned with the corresponding connecting rebars  43  extending from the top surface  42  of the precast RC column  4  and the bottom of the hollow rectangular steel frame  10  corresponds to the space S surrounded by the connecting rebars  43 . In addition, the four first auxiliary spiral stirrups  32  surround the connecting rebars  43  provided at the four top corners of the precast body  41  and the first main spiral stirrup  31  surrounds the rest of the connecting rebars  43  when the beam-column joint structure  1  is descended by the hoister toward the precast RC column  4 . As shown in  FIG. 3 , some of the connecting rebars  43  may be surrounded by both the first main spiral stirrup  31  and the first auxiliary spiral stirrups  32 . Furthermore, in the vertical direction, the first main spiral stirrup  31  of the beam-column joint structure  1  is aligned with and arranged to be connected to the second main spiral stirrup  44  of the precast RC column  4 , and the four first auxiliary spiral stirrups  32  of the beam-column joint structure  1  are respectively aligned with and arranged to be connected to the four second auxiliary spiral stirrups  45  of the precast RC column  4 . 
     During the process in which the beam-column joint structure  1  is descended by the hoister to be assembled with the precast RC column  4 , the pertinent connecting rebars  43  are first inserted into the holes H 2  in the bottom flanges A 2  of the H-beams  22 ,  23 ,  24  and then these connecting rebars  43  are further inserted into the holes H 3  in the top flanges A 1  of the H-beams  22 ,  23 ,  24  (see  FIG. 5 ). The beam-column joint structure  1  will be descended until the bottom of the bottom flanges A 2  abuts against the adjusters  46  on the connecting rebars  43  of the precast RC column  4  so that the beam-column joint structure  1  is placed at a predetermined height. 
     As shown in  FIG. 6 , when the beam-column joint structure  1  has been placed at a predetermined height, the ends of the pertinent connecting rebars  43  are exposed from the top flanges A 1  of the H-beams  22 ,  23 ,  24 . Thereafter, fasteners  46 ′ are sleeved on the ends of the pertinent connecting rebars  43  and are rotated or moved to abut against the top surface of the top flanges A 1  of the H-beams  22 ,  23 ,  24 . Then, formworks (not shown) are provided to seal the space above the precast RC column  4  and around the beam-column joint structure  1  for concrete grouting. After the concrete has reached its initial set or final set, the formworks are removed and the finished construction is as shown in  FIG. 7 . 
       FIG. 8  is a schematic view showing a beam-column joint structure  1 ′ in accordance with another embodiment of the instant disclosure. The beam-column joint structure  1 ′ comprises a first steel plate  15 ′ fixed in and near the top of the hollow rectangular steel frame  10 ′ and a second steel plate  16 ′ fixed in and near the bottom of the hollow rectangular steel frame  10 ′. The first steel plate  15 ′ and the second steel plate  16 ′ have openings  17 ′ in their centers wherein each of the first steel plate  15 ′ and the second steel plate  16 ′ has notches  18 ′ at four corners thereof. In operation, concrete is grouted into the hollow rectangular steel frame  10 ′ through the opening  17 ′ of the first steel plate  15 ′ and concrete may be filled between the beam-column joint structure  1  and the precast RC column  4  (see  FIGS. 10-12 ) through the opening  17 ′ of second steel plate  16 ′. The notches  18 ′ of the first steel plate  15 ′ and the second steel plate  16 ′ are for air to be expelled out of the hollow rectangular steel frame  10  ‘ when concrete is grouted into the hollow rectangular steel frame  10  through the opening  17 ’ of the first steel plate  15 ′ so that the concrete would contain less air when the concrete reaches its final set. As shown in  FIG. 8 , the first steel plate  15 ′ comprises a plurality of first through holes  19 ′ therein and the second steel plate  16 ′ comprises a plurality of second through holes  20 ′ therein, and the plurality of first through holes  19 ′ are generally aligned with the plurality of second through holes  20 ′ for connecting rebars  43  (see  FIG. 10 ) of the precast RC column  4  to pass through. 
       FIG. 9  is a schematic view showing a beam-column joint structure  1 ′ in accordance with a further embodiment of the instant disclosure. As shown in  FIG. 9 , the first sidewall  11 ′ of the hollow rectangular steel frame  10 ′ is not provided with an H-beam, whereas each of the second sidewall  12 ′, the third sidewall  13 ′ and the fourth sidewall  14 ′ is provided with one H-beam  22 ′,  23 ′,  24 ′. In addition, the central axes along the lengthwise direction of the plurality of H-beams  22 ′,  23 ′,  24 ′ are not aligned with the first axis X 1  (not shown) or the second axis X 2  (not shown) of the hollow rectangular steel frame  10 ′. That is, the H-beams in the embodiment of  FIG. 10  are asymmetrical with respect to the hollow rectangular steel frame  10 ′. 
       FIGS. 10-12  are schematic views showing the processes that the beam-column joint structure  1 ′ shown in  FIG. 9  is assembled with the precast RC column shown in  FIG. 3  and then the assembled structure is covered with concrete. As shown in  FIG. 10 , the width and the length of the hollow rectangular steel frame  10 ′ are smaller than those of the precast RC column  4 . When the beam-column joint structure  1 ′ is hoisted by a hoister (not shown) above the precast RC column  4 , the connecting rebars  43  extending from the top of the precast RC column  4  are aligned with the plurality of the first through holes  19 ′ of the first steel plate  15 ′ and the plurality of the second through holes  20 ′ of the second steel plate  16 ′. 
     As shown in  FIG. 11 , when the beam-column joint structure  1 ′ is descended by the hoister (not shown), the connecting rebars  43  extending from the top of the precast RC column  4  are inserted into the second through holes  20 ′ of the second steel plate  16 ′ and then the ends of the connecting rebars  43  are inserted into and exposed from the first through holes  19 ′ of the first steel plate  15 ′. 
     The beam-column joint structure  1 ′ will be descended by the hoister (not shown) until the bottom of the second steel plate  16 ′ abuts against the adjusters  46  on the connecting rebars  43  of the precast RC column  4  so that the beam-column joint structure  1 ′ is placed at a predetermined height. Thereafter, fasteners  46 ′ are sleeved on the ends of the pertinent connecting rebars  43  and are rotated or moved to abut against the top surface of the first steel plate  15 ′. Then, formworks (not shown) are provided to seal the space above the precast RC column  4  and around the beam-column joint structure  1  for concrete grouting. After the concrete has reached its initial set or final set, the formworks are removed and the finished construction is as shown in  FIG. 12 . 
     As shown in  FIGS. 9-12 , no stirrups are provided around the outer circumference of the hollow rectangular steel frame  10 ′. This is because in the embodiment shown in  FIGS. 9-12 , the vertically positioned connecting rebars  43  are all confined within the hollow rectangular steel frame  10 ′ and are fixed to the first steel plate  15 ′ and the second steel plate  16 ′. That is, the first sidewall  11 ′, the second sidewall  12 ′, the third sidewall  13 ′ and the fourth sidewall  14 ′ of the hollow rectangular steel frame  10 ′ serve the same function as stirrups for confining the connecting rebars  43  and the concrete therein. 
     In alternative embodiments, the beam-column joint structure  1  according to  FIGS. 2-7  or the beam-column joint structure  1 ′ according to  FIGS. 9-12  may be assembled with concrete columns made on site. That is, the concrete columns are not limited to precast RC columns in the instant disclosure. In addition, the H-beams in these embodiments may be replaced with steel beams of different shapes, such as I-beam, C-beam, T-beam etc. 
     The above embodiments merely describe the principle and effects of the present disclosure, instead of limiting the present disclosure. Therefore, persons skilled in the art can make modifications to and variations of the above embodiments without departing from the spirit of the present disclosure. The scope of the present disclosure should be construed as that defined by the appended claims.