Abstract:
A system for constructing multi-story building is disclosed. The system can include a plurality of vertical beams and a base beam section. The base beam section can be supported horizontally between the plurality of vertical column members and can include a composite shear connector attached thereto. The framing system can further include a plurality of concrete plank sections spanning perpendicularly to, and supported by, either side of the base beam. The plurality of concrete plank sections can be assembled in pairs. The framing system can also include grout material applied to the composite shear connector and the concrete plank sections to fill the cavities of the assembly to provide an integral framing system. A method for assembling such a system is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/915,840, entitled “Open Web Composite Shear Connector Construction,” filed on Dec. 13, 2013, which is incorporated herein by reference in its entirety as if fully set forth below. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present technology relate to the construction of multi-story buildings, and more particularly to an improved structural framing system and associated method for construction of such buildings. The system comprises a composite concrete and steel assembly, which can incorporate one or more steel beams disposed between, and joined along, adjacent edges of precast concrete plank members such that the composite strength of the structure is substantially enhanced. 
     BACKGROUND OF RELATED ART 
     When constructing a multi-story building, the framing system is generally the load bearing structure that supports the building. Commercial framing, for example, typically consists of vertical steel beams with horizontal beams spanning between them. The floor of each story is typically a concrete slab that rests upon the horizontal beams of the framing structure. This floor slab can be steel reinforced concrete and can be attached to, or poured around, the framing beams. The framing system is designed to carry all of the anticipated floor and roof loads as well as provide stabilization against horizontal forces due to, for example, wind and seismic loads. The floor slab in particular is generally required to transmit such forces to building lateral systems, such as moment frames, braced frames, and shear walls, provided throughout the framing system in order to satisfy the minimum design requirement per building code. 
     In recent years, revisions to the national and international building code standards have increased lateral load requirements for seismic design criteria, especially the requirements for multi-story building construction. As a result, the framing systems of most prospective multi-story building structures will be required to resist lateral loads greater than those able to be accommodated by existing structural framework. Because of the increased seismic design criteria and the continuing pressure of minimizing construction costs, among other things, new design alternatives for structural framing systems have been developed to meet all current loading requirements imposed upon modern multi-story buildings in an economical and cost-effective manner. One of the recent developments in the field of building construction is to use prefabricated building components, such as precast concrete slab and wall panels, steel structures and other elements that can be manufactured in controlled environment. These precast concrete components are widely used in modern building construction. These prefabricated components can be easily erected and assembled in construction sites to greatly reduce the cost, fieldwork, and construction duration. U.S. Pat. No. 4,505,087, entitled “Method of construction of concrete decks with haunched supporting beams,” discusses a method of construction of concrete decks utilizing precast members over which concrete is poured to form a monolithic structure. One problem associated with structures built from the precast concrete components is the overall integrity. U.S. Pat. No. 4,081,935 A, entitled “Building structure utilizing precast concrete elements,” discusses a construction method for improving the structural integrity of such structures by applying cast concrete over the precast concrete slab panels and beams. However, there are other integrity problems left unanswered. For example, in some situations, structural steel and precast concrete members are desired to be used together in constructing a building. Currently, technologies for integrating these two types of materials are underdeveloped, which, as a result, inevitably hinders constructions based on these types of materials. 
     Another recent design alternative for a structural framing system is described in U.S. Pat. No. 6,442,908 wherein a dissymmetric steel beam having a narrowed, thickened top flange, a widened bottom flange, and a web having trapezoidal openings extending therebetween is adapted to be horizontally disposed between adjacent vertical steel columns that are erected upon conventional foundations. Standard hollow core sections of precast concrete plank are assembled together perpendicularly to the open web dissymmetric beam. The planks are supported by the bottom flange on either side, such that the open web of the beam is centrally disposed between end surfaces of the plank sections in substantially the same horizontal plane. A high-strength grout mixture applied to the assembled beam and plank sections is made to flow completely through the web openings in a circulatory manner thereby creating a substantially monolithic concrete encasement around the dissymmetric beam. This improves the resulting composite action and mechanical interlock between the steel beam and concrete plank and reduces loss of strength due to separation of the grout from either side of the beam. 
     While initial testing indicates that the framing system of the aforementioned patent has increased load bearing, testing has also indicated a need to enhance the composite action. In response, embodiments of the present technology relate to an open-web shear connector composite beam system, which combines some of the benefits of the conventional open-web castellated beam system and composite construction. In this configuration, the precast beams can act with steel beams, and can greatly increase the bending strength of the beams. The open web composite shear connectors can also act compositely with the base beam to further increase the bending strength of the system. Precast concrete planks and/or panels can be easily set on the steel beams with no interference from beam flanges during erection. The open-web of the composite shear connectors can enable the precast concrete deck to be integrated with the steel beam to provide required composite action. Reinforcement can be added and can provide, for example, additional shear strength, ductility, and toughness. Improved and increased ductility can greatly improve the seismic resistant characteristics of a structure. This improvement may be further enhanced if precast concrete filigree panels are utilized. 
     The system can be utilized for building within a wide range of span lengths. The system also provides a wide range of load capacities, which can enable the system to meet the demands of, for example and not limitation, residential, industrial, and commercial applications. The use of precast concrete panels can also reduce construction duration significantly. Precast panels can also minimize weather delays, since conditions such as humidity, precipitation, and temperature no longer affect the ability to pour and properly set concrete (i.e., the panels can be precast and cured in controlled conditions and then transported to the job site). 
     SUMMARY 
     Embodiments of the present technology are directed to a structural framing system for a multi-story building. The framing system can include a plurality of vertical column members. The system can also include a base beam section, supported horizontally between the plurality of vertical column members, and having a composite shear connector attached thereto. The framing system can further include a plurality of concrete plank sections and spanning perpendicularly to, and supported by, either side of the base beam. In some embodiments, the plurality of concrete plank sections can be assembled in pairs. In some embodiments, the framing system can also include grout material applied to, for example and not limitation, the composite shear connector and concrete plank sections to fill the cavities of the assembly and provide increased strength to the framing system. 
     One aspect of the present technology relates to a structural framing system for supporting a building. The system may include a plurality of vertical column members. The vertical column members may support a horizontal base section. A pair of concrete plank sections may be arranged in a linear fashion and disposed above and perpendicular to the base section. Each concrete plank section may define a passage therethrough. A composite shear connector may be disposed above the base section and between the pair of concrete plank sections. The shear connector may define an opening in communication with the passages of the concrete plank sections. A reinforcement bar may be disposed across the opening of the shear connector. The reinforcement bar may extend into the passages of the concrete plank sections. The shear connector and the concrete plank sections may define a cavity. An adhesive material may fill in the cavity. 
     Embodiments of the present technology can also be directed to a method of constructing a structural framing system. The method can include erecting a plurality of vertical columns and supporting a plurality of base beams horizontally therefrom with a plurality of the open web composite shear connectors. The method can also include installing a plurality of concrete plank sections and installed on either side of the base beam. In some embodiments, the plurality of concrete plank sections can be assembled in pairs. The method can additionally include applying a grout material to cavities between the plank sections and open web composite shear connectors to provide a mechanical connection therebetween. 
     One aspect of the present technology relates to a method for assembling a structural framing system. The method may include erecting a plurality of vertical column members. A horizontal base section may be secured to the plurality of vertical column members. A pair of concrete plank sections may be arranged in a linear fashion above and perpendicular to the base section. Each concrete plank section may define a passage therethrough. The method may include disposing a composite shear connector above the base section and between the pair of concrete plank sections. The shear connector may define an opening in communication with the passages of the concrete plank sections. A reinforcement bar may be disposed across the opening of the shear connector. The reinforcement bar may extend into the passages of the concrete plank sections. The shear connector and the concrete plank sections may define a cavity. The method may also include filling an adhesive material into the cavity. 
     These and other objects, features, and advantages of the present technology will become more apparent upon reading the following specification in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  and  FIG. 1B  are fragmentary perspective views of an assembled structural framing system, in accordance with some embodiments of the present disclosure; 
         FIG. 2A  and  FIG. 2B  are cross-sectional views of the assembled structural framing system of  FIG. 1A  and  FIG. 1B , respectively, in accordance with some embodiments of the present disclosure; 
         FIG. 3  is a cross-sectional view of a second embodiment of the assembled structural framing system, in accordance with some embodiments of the present disclosure; 
         FIG. 4  is a cross-sectional view of a third embodiment of the assembled structural framing system of the present disclosure, in accordance with some embodiments of the present disclosure; 
         FIG. 5  is a cross-sectional view of a fourth embodiment of the assembled structural framing system of the present disclosure, in accordance with some embodiments of the present disclosure; 
         FIG. 6  is a cross-sectional view of a fifth embodiment of the assembled structural framing system of the present disclosure, in accordance with some embodiments of the present disclosure; 
         FIG. 7  is a cross-sectional view of a sixth embodiment of the assembled structural framing system of the present disclosure, in accordance with some embodiments of the present disclosure; and 
         FIG. 8  is a diagrammatic representation of a continuous cutting pattern employed to obtain an exemplary open-web composite shear connector, in accordance with some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary structural framing system  10 A in accordance with some embodiments of the present technology is illustrated in  FIG. 1A . Framing system  10 A can comprise a vertical column  12  connected to a base beam  14 . This connection can be made using, for example, a clip angle connector (sometimes also referred to as an angle web cleat or web bracket)  16 . Web bracket  16  can be, for example, bolted, riveted, or welded to vertical column  12  and base beam  14 . This connection can provide the vertical support for base beam  14  and all of the floor loads. This connection can also provide horizontal support for countering shear loads passed through the floor due to wind and the like. 
     Base beam  14  can be, for example and not limitation, a standard rolled steel beam section, plate, or a welded plate girder. Base beam  14  can have one or more channels. In some embodiments, base beam  14  can be a castellated or cellular beam. A series of precast concrete planks  18 A can be laid down on top of a flange  20  of base beam  14 . Based on the application, flange  20  of base beam  14  can be multiple shapes and sizes. In the case of a base beam  14  section that is a flat steel plate, for example, the flange  20  can be the upper surface of that plate. 
     Precast concrete planks  18 A can be, for example, conventional pre-stressed concrete members. Of course, other types of planks are known in the art of building construction and are contemplated herein. In some embodiments, concrete planks  18 A can have grooves or passages  22  (also known as hollow cores) formed therein to enable reinforcement bars  24 , wiring, plumbing, and other components to pass through them. In some embodiments, the concrete planks  18 A can be formed such that a pair of planks contains corresponding grooves that formed passages  22  when joined together. In other embodiments, concrete planks  18 A can be cast with passages  22  running through a single plank. 
     In some embodiments, a composite shear connector  26  can be included to provide additional structure to framing system  10 A. In some embodiments, the open web composite shear connector  26  can be fabricated by taking an I-beam and cutting it in half according to a pattern such as illustrated in  FIG. 6  and discussed below. In other embodiments, the composite shear connector  26  can be manufactured using other suitable methods including being fabricated from plate, cast, or CNC machined, among other methods known in the art. The composite shear connector  26  can be joined to base beam  14  at joint  28 . Joint  28  can include many suitable methods known in the art of connecting two beams including, for example and not limitation, welding, riveting, or bolting. 
       FIG. 1B  illustrates framing system  10 B. Similar to framing system  10 A, framing system  10 B can comprise a vertical column  12  connected to a base beam  14 . Also similar to system  10 A, a series of precast concrete planks  18 B can be laid down on top of a flange  20  of base beam  14 . Planks  18 B may be pre-stressed concrete planks reinforced with reinforcement bar  31 . Reinforcement bar filigree  27  may be placed on top of concrete planks  18 B, and may be arrayed using parallel reinforcement bar  29 , and perpendicular reinforcement bar  33 . As in  FIG. 1A , reinforcement bar  24  may run through the openings in shear connector  26 , but alternatively or additionally, reinforcement bar  24  may run above shear connector  26 . 
     Once the concrete planks  18 A or  18 B, reinforcement bar  24 , and composite shear connector  26  are in place on base beam  14 , a high strength grout or concrete can be applied over the concrete panels  18 A or  18 B. This material can fill the passages  22  and other voids in framing system  10 A or  10 B to form an integral, composite floor system  10 A or  10 B. 
       FIG. 2A  shows a cross-sectional view of the integrated structural framing system  10 A of  FIG. 1A . In some embodiments, cast-in-place concrete, hydraulic cement, or grout  30  can fill the voids in the system  10 A and can encase the reinforcement bar  24  in passages  22 . In some applications of the present disclosure, a dam  32  can be utilized to prevent concrete  30  from filling the entire passage  22  in concrete plank  18 A. This can enable less concrete to be used in construction, thus saving time, weight, and material cost. Alternatively, the entirety of passage  22  can be filled. 
       FIG. 2B  shows a cross-sectional view of the integrated structural framing system  10 B of  FIG. 1B . In some embodiments, cast-in-place concrete, hydraulic cement, or grout can fill the voids in the system  10 B and can encase the reinforcement bar  24 , reinforcement bar filigree  27 , parallel reinforcement bar  29 , and perpendicular reinforcement bar  33 . The resulting structure may be a unitary piece of concrete or the like, that is reinforced by the reinforcement bar  24 , reinforcement bar filigree  27 , parallel reinforcement bar  29 , and/or perpendicular reinforcement bar  33  that it encases. 
     Once the concrete  30  has been poured to form an integrated system, a concrete overlay  34  can be poured or placed. Concrete overlay  34  can be used to provide a smooth surface on which to lay hardwood, carpet, or other flooring, or can simply be polished or textured for use as a flooring surface. In some embodiments, concrete overlay  34  can serve as both an overlay as well as grout  30 . Concrete overlay  34  can increase the vertical and lateral strength of the flooring system, and improve the overall structural integrity of the building system. 
       FIG. 3  shows a cross-sectional view of a second embodiment of a structural framing system  310 . In some embodiments, the base beam section  314  can be steel plate or the like. The rest of the construction can be similar to system  10 A, with concrete planks  318 , passages  322 , reinforcement bar  324 , concrete fill  330 , dam  332 , and concrete overlay  334 . Joint  328  can be similar to the joint  28 , discussed above, and used to connect shear connector  326  to steel plate  314 . 
       FIG. 4  shows a cross-sectional view of a third embodiment of a structural framing system  410 . In some embodiments, the base beam section  414  can comprise one or more steel channels, which can be welded, or otherwise joined, to either side of shear connector  426 . In this configuration, the rest of the construction can be similar to system  10 A, with concrete planks  418 , passages  422 , reinforcement bar  424 , concrete fill  430 , dam  432 , and concrete overlay  434 . Joint  428  can be similar to the joint  28 , discussed above, and used to connect shear connector  426  to beam section  414 . 
       FIG. 5  shows a cross-sectional view of a fourth embodiment of a structural framing system  510 . In this configuration, the base beam section  514  can comprise one or more steel channels bolted to either side of shear connector  526  with bolts  536 , rivets, welds, or otherwise suitably joined. The rest of the construction can be similar to system  10 A, with concrete planks  518 , passages  522 , reinforcement bar  524 , concrete fill  530 , dam  532 , and concrete overlay  534 . 
       FIG. 6  shows a cross-sectional view of a fifth embodiment of a structural framing system  610 . In some embodiments, the base beam section  614  can comprise one or more steel tubes, which can be welded, or otherwise joined, to either side of shear connector  626 . In this configuration, the rest of the construction can be similar to system  10 A, with concrete planks  618 , passages  622 , reinforcement bar  624 , concrete fill  630 , dam  632 , and concrete overlay  634 . Joint  628  can be similar to the joint  28 , discussed above, and used to connect shear connector  626  to steel plate  614 . Base beam  614  can be used, for example, to resist torsion in applications requiring additional stiffness without a corresponding increase in mass (e.g., for particularly long floor spans). 
     Similarly,  FIG. 7  shows a cross-sectional view of a sixth embodiment of a structural framing system  710 . In some embodiments, the base beam section  714  can comprise a steel channel positioned horizontally, which can be welded, or otherwise joined, to either side of shear connector  726 . In this configuration, the rest of the construction can be similar to system  10 A, with concrete planks  718 , passages  722 , and concrete fill  730 . 
     An exemplary cutting pattern for manufacturing an open web composite shear connector  826  is illustrated in  FIG. 8 . Connector beam  40  can be, for example, a wide flange section, I-section, S-section, channel, or other shape of beam. In some embodiments, the beam  40  can be cut along cut line  42  to form two composite shear connectors  826 . It is contemplated that if cut line  42  is chosen to generate substantially symmetrical shear connectors  826 , then the resulting pieces can be used along the same base beam. However it is further contemplated that cut line  42  can result in asymmetrical shear connectors  826  to meet different load or design requirements. In this configuration, the resulting pieces can be used, for example, on different parts of a building&#39;s construction or, for example, on different buildings to minimize material waste. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structural framing system of the present disclosure without departing from the scope of the disclosure. For example, the system is described above as being welded, bolted, or riveted together. One skilled in the art will realize, however, that other suitable methods of joining components exist. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the building system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the invention being indicated by claims, and their equivalents, in subsequent, related non-provisional patent applications.