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.
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).
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.
An exemplary structural framing system 10A in accordance with some embodiments of the present technology is illustrated in
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 18A 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 18A 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 18A 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 18A can be formed such that a pair of planks contains corresponding grooves that formed passages 22 when joined together. In other embodiments, concrete planks 18A 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 10A. 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
Once the concrete planks 18A or 18B, 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 18A or 18B. This material can fill the passages 22 and other voids in framing system 10A or 10B to form an integral, composite floor system 10A or 10B.
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.
Similarly,
An exemplary cutting pattern for manufacturing an open web composite shear connector 826 is illustrated in
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.
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.
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Number | Date | Country | |
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20150167289 A1 | Jun 2015 | US |
Number | Date | Country | |
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61915840 | Dec 2013 | US |