Stackable Mid-Rise Structures
A system of structural steel modular units useful in constructing mid-rise building between 3-8 stories high. Modular units are in the shape of rectangular boxes and the height of the units define a single story of the mid-rise building. Modular units are configured to be stackable onto each other such that they can couple to both modular units positioned directly above and below and also to couple to laterally adjoining modular units. The modular units can include cantilevered extensions to define hallways or other desirable features such as balconies. The systems can also utilize a post tension system that includes a plurality of post tension members anchored to a foundation and are coupled to a damper system positioned on the roof of the building.
America is undergoing a significant shift away from low density suburban sprawl to moderate density urban revitalization in both our major cities and to some extent mid-sized towns. These changes have been brought about by several factors in recent years including:
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- The public's awareness of environmental issues such as global warming, efficient utilization of scarce natural resources and a desire to preserve open space.
- The growing trend toward “GREEN” technology in all aspects of our lives including the appropriate types of future development within our cities and towns.
- The desire by both young and old to live, work and play in pedestrian oriented, walkable communities designed around the concept of “Smart Growth.”
- The economic realities of today's high energy costs have families rethinking their priorities by considering smaller, denser housing alternatives in centralized locations.
- Many well educated singles, young couples and empty nesters continue to embrace denser, urban living in revitalized areas of many major to mid-sized cities.
- Many City and County planning agencies now mandate higher density future development in order to reduce long term service and maintenance costs.
The goals and trends discussed above can be realized through concentrating future development within in-fill areas of cities where housing, employment, shopping, recreation and cultural activities are in close proximity. Over the last five years many community leaders have elected to revise their general plans to earmark their community's central core for more moderate-to-high density future development. Most of this “up-zoning” within in-fill areas has focused on moderate density increases from what would be considered low-rise buildings (one to three stories) to mid-rise structures (four to eight stories). This up-zoning within a city's central core is thought to be a paradigm shift in the industry, rather than merely a temporary adjustment. This change from lower density to higher density structures will likely accelerate over the coming years. The question then becomes how to best produce new mid-rise structures that are appropriately sized and cost effective within these infill areas.
Stackable Mid-Rise (SMR) Structures is a steel modular building system designed to meet the needs of a changing industry. As an entirely new method of construction, SMR Structures makes use of cutting edge technology to deliver a high quality, efficient structural building system. SMR modular units are pre-engineered, factory produced, structural steel modular units that are transported to the building site and craned into place to construct 3 to 8 story buildings.
Although multi-story modular construction is unique, some foreign and domestic developers have stacked refurbished cargo containers or other types of structures to form utilitarian multi-story apartments, condos, or offices. Most of these factory built, stacked modular projects have occurred in Western Europe and Asia, but few have been done well. In most cases, the end product emphasizes the modular aspects of the structure resulting in very unappealing architecture. There have also been companies that produce factory built light gauge steel floor trusses, wall panels and roof trusses which are trucked to the job site and assembled in the field to form a base structural framework for multi-story buildings. Light gauge steel buildings over three stories high may also require costly structural masonry core or steel brace frame system in order to meet wind and seismic requirements. In addition these light gauge steel structures are not modular, so the end result is basically a prefabricated structural framework. The balance of construction activities including exterior windows, doors, and cladding as well as all work interior to the unit still needs to be accomplished in the field conventionally, so any time saving in the construction process is minimal compared to the modular building system which will be discussed below.
Therefore, what is needed is a modular or componentized building system that is largely pre-built off site, wherein the components can be stacked and connected to each other at the jobsite. Moreover, the building system must be sufficiently strong to resist seismic and wind loads, while also reducing the amount of material needed.
2.0 SUMMARY OF THE INVENTIONThe teachings herein are directed to modular systems for constructing mid-rise buildings and comprising: a plurality of structural steel, modular units configured to be stackable upon each other such that the height of a modular unit defines a single story in the mid-rise building, wherein the plurality of modular units are individually comprised of first and second moment frames and each moment frame includes two vertical columns coupled to a floor beam and a ceiling beam such as to define a right-angled quadrilateral, and wherein the first and second moment frames are coupled to each other by two long span floor beams and two long span ceiling beams to define a rectangular-box shape.
Further embodiments herein are directed to modular systems for constructing a mid-rise building having a roof and a foundation comprising: a plurality of structural steel, rectangular-box-shaped, modular units configured to be stackable upon each other such that the height of a modular unit defines a single story in the mid-rise building; a damper system coupled to the roof of the mid-rise building; and a plurality of post tension members selected from the group consisting of: post tension rods and post tension cables, wherein the post tension members are anchored to the foundation and are coupled to the damper system.
SMR modular units are pre-engineered, factory produced, structural steel modular units that are transported to the building site and craned into place to construct 3 to 8 story buildings. Each modular unit may be comprised of various sized structural steel members that are robotically welded together in the factory via an assembly line process, similar to that of an automobile plant. During the assembly process each unit may move through a series of work stations and exit the assembly line complete with exterior and interior walls in place; plumbing, electrical and mechanical equipment roughed in and most interior finishes either in place or packaged and ready for final installation in the field. Once completed, SMR modular units are trucked to the building site, lifted into place by crane, secured with high strength slip critical bolts and then finished on-site to form 3 to 8 story mid-rise buildings. Uses include Residential (condominiums, apartments and single occupancy residences); Commercial (offices, medical suites and hotel rooms); Educational/Institutional (school classrooms, dormitories and hospital rooms); Government/Military (offices, temporary quarters and permanent barracks) and potentially other uses such as multi-story urban infill storage facilities.
Fabrication of SMR units may be compatible with a wide range of environmentally sustainable materials and techniques through the system's use of state of the art manufacturing technology. These design considerations may help developers obtain Leadership in Energy and Environmental Design (LEED) certification from the U.S. Green Building Council in recognition of green building practices for their projects.
The fabrication of SMR units may start concurrently with a project's site work. Unlike conventional construction, this parallel process allows for a building's structural elements, as well as a substantial portion of the building's finish work, to occur at the same time as grading, under-grounding of utilities, and pouring of foundations. Through this expedited process, SMR's modular units can be onsite and ready to be craned into place upon the completion of a project's site work, representing considerable cost and time savings when compared to conventional construction methods.
4.1 SMR Modular Unit Construction
Each modular unit may be constructed of a series of moment frames that resist lateral loads in the event of seismic/wind activity. Moment frames in SMR's structural system consist of two tube steel columns and two wide flange steel beams as can be seen in
Now that the moment frame (100) has been described, the base structure of each modular unit will be discussed with reference to
This basic SMR modular unit has significant advantages over conventional construction. Conventionally constructed mid-rise buildings typically have either brace frames, moment frames or concrete core/shear walls to handle lateral forces during seismic or wind events. During seismic/wind events in conventionally constructed mid-rise buildings, lateral loads from those events generally are transferred to these frames or shear walls. If any of these moment frames, brace frames or shear walls fail due to seismic/wind events or through faulty construction, the failure could be catastrophic effecting loss of life not to mention damage, possibly beyond repair, to the building. The SMR modular unit construction, however, contains at least two moment frames per unit with several modular units joined together and stacked to form buildings with many moment frames creating structural redundancy which bolsters the structural integrity of the entire building. Should any one of these moment frames fail, the failure may be very localized minimizing damage to the building and loss of life. If the damage is only localized, the building can be effectively repaired.
4.2 SMR Modular Unit Connections
For speed and ease of construction SMR modular units have been designed to be stacked into place on the job site and connected without the use of field welding. In place of field welds, high strength slip critical bolts and a series of connection plates may be used to attach modular units both vertically and horizontally. At the end of a conventional mid-rise building's life cycle, buildings are typically either imploded or demolished, but SMR's bolted connection plate system allows modular units to be disassembled for relocation, re-use, or recycling.
Another type of connection plate that may be utilized by SMR's structural system is the floor truss stitch plate.
Another function of a floor truss stitch plate is to create air space between floor and ceiling systems (410) of stacked units allowing for ducting and conduit to be run between modular units.
4.3 SMR Roof System
Once a building's modular units have been stacked into place and connected using the various methods previously described, the column cap plates (300) of the building's top floor receive SMR's roof system.
4.4 SMR Structures Completed Building
SMR modular units, when paired with the various connections and systems described above, give architects and developers a tool kit of pre-engineered building blocks that can be pieced together to form a multitude of building configurations.
Although
4.5 SMR Post Tension System (High Seismic/Wind)
In high seismic/wind regions, or as determined by structural engineers, SMR's post tension system may be utilized to provide additional structural strength.
This energy dampening device will be placed between pairs of columns as determined by the structural engineer. Some or all columns may require the dampening system depending on a buildings site conditions. From the foundation to the roof, the building is now vertically connected with post tension rods (or cables) to dampen energy from lateral forces on the structure resulting from seismic activity or high winds. The post tension system is engineered so that in a strong seismic/wind event the entire structure will flex, then return to the neutral position after the event as a result of the post tension energy dampening system.
Other seismic stability systems are concerned with maintaining the building's structural integrity only to the point of allowing the inhabitants to escape unharmed; however, the building is often too damaged afterwards to be repaired and must be razed. The SMR system using post-tension rods or cables and energy dampening device automatically brings the building back into the neutral position such that after a seismic event the building, while experiencing some cosmetic damage, would be structurally sound and could be repaired.
While particular embodiments of SMR structures have been disclosed, various modifications and extensions of the above described technology may be implemented using the teachings described above. All such modifications and extensions are intended to be included within the true spirit and scope of this patent application.
Claims
1. A modular system for constructing a mid-rise building comprising:
- a plurality of structural steel, modular units configured to be stackable upon each other such that the height of a modular unit defines a single story in the mid-rise building,
- wherein the plurality of modular units individually comprise first and second moment frames each individually including two vertical columns coupled to a floor beam and a ceiling beam such as to define a right-angled quadrilateral, and
- wherein the first and second moment frames are coupled to each other by two long span floor beams and two long span ceiling beams to define a rectangular box.
2. The modular system of claim 1, wherein a first modular unit, selected from the plurality of modular units, further comprises:
- a first upper extension comprising steel wide flange beams cantilevered outward from the vertical columns of the first modular frame such that they are substantially aligned with the two long span ceiling beams, and
- a first lower extension cantilevered outward from the vertical columns of the first modular frame such that they are substantially aligned with the two long span floor beams, and
- wherein the first upper and lower extensions define an extension selected from the group consisting of: a first outlooker extension and a first hallway extension.
3. The modular system of claim 2, wherein the first upper and lower extension define a first hallway extension, and the modular system further comprises a second modular unit, selected from the plurality of modular units, having a second upper extension and a second lower extension that define a second hallway extension configured to couple to the first hallway extension of the first modular steel unit to define a hallway in the mid-rise building.
4. The modular system of claim 1, wherein the plurality of modular units individually comprise multiple floor truss stitch plates positioned on the underside of the long span floor beams on upper modular units that are configured to couple to the topside of long span ceiling beams of vertically adjoining, modular units stacked below the upper modular units to create a truss system where the physical stress points are shifted from the coupling points of the vertical columns along a neutral horizontal axis to positions at the top and bottom of the truss system further along the vertical columns.
5. The modular system of claim 4, further comprising:
- a plurality of floor truss stitch plate couplers that are configured to secure a first floor truss stitch plate positioned on a first modular unit to a second floor truss stitch plate positioned on a laterally adjacent second modular unit.
6. The modular system of claim 1, further comprising:
- a plurality of column connector plates, wherein the plurality of modular units individually comprise cap plates on top of the vertical columns, and base plates on the bottom of the vertical columns, and
- wherein the cap plates and base plates are configured to attach to the column connector plates such that a cap plate positioned on top of a vertical column on a lower modular unit, can be coupled to a base plate on the bottom of a vertical column of an upper modular unit that is stacked on top of the lower modular unit.
7. The modular system of claim 6, wherein the plurality of column connector plates are configured to allow attachment of four separate modular units including: the cap plates of two vertical columns, each from two separate horizontally adjacent lower modular units and the base plates of two vertical columns, each from two separate horizontally adjacent upper modular units stacked on top of the two lower modular units.
8. The modular system of claim 7, further comprising:
- a roof comprising a damper system positioned on top of the mid-rise building, a foundation beneath the mid-rise building, and a plurality of post tension members selected from the group consisting of: post tension rods and post tension cables,
- wherein the post tension members are anchored to the foundation and are coupled to the damper system.
9. The modular system of claim 8, wherein the plurality of column connector plates further comprise centrally positioned, vertical apertures configured to allow the post tension members to pass through.
10. The modular system of claim 8, wherein the post tension members are individually strung through an upper and lower damper sleeve that encase and are configured to compress a rubber dampening mechanism such as to pre-load the mid-rise building to a pre-engineered compression.
11. A modular system for constructing a mid-rise building having a roof and a foundation comprising:
- a plurality of structural steel, rectangular-box-shaped, modular units configured to be stackable upon each other such that the height of a modular unit defines a single story in the mid-rise building;
- a damper system coupled to the roof of the mid-rise building;
- and a plurality of post tension members selected from the group consisting of: post tension rods and post tension cables, wherein the post tension members are anchored to the foundation and are coupled to the damper system.
12. The modular system of claim 11, wherein each post tension member of the plurality of post tension members is configured, in the absence of an external force, to experience approximately the same amount of tension such that the mid-rise building is in a state of equilibrium.
13. The modular system of claim 12 wherein the plurality of modular units individually comprise first and second moment frames each individually including two vertical columns coupled to a floor beam and a ceiling beam such as to define a right-angled quadrilateral, and wherein the first and second moment frames are coupled to each other by two long span floor beams and two long span ceiling beams to define a rectangular box shape.
14. The modular system of claim 13, wherein a first modular unit, selected from the plurality of modular units, further comprises:
- a first upper extension comprising steel wide flange beams cantilevered outward from the vertical columns of the first modular frame such that they are substantially aligned with the two long span ceiling beams, and
- a first lower extension cantilevered outward from the vertical columns of the first modular frame such that they are substantially aligned with the two long span floor beams, and
- wherein the first upper and lower extensions define an extension selected from the group consisting of: a first outlooker extension and a first hallway extension.
15. The modular system of claim 14, wherein the first upper and lower extension define a first hallway extension, and the modular system further comprises a second modular unit, selected from the plurality of modular units, having a second upper extension and a second lower extension that define a second hallway extension configured to couple to the first hallway extension of the first modular steel unit to define a hallway in the mid-rise building.
16. The modular system of claim 13, wherein the plurality of modular units individually comprise multiple floor truss stitch plates positioned on the underside of the long span floor beams on upper modular units that are configured to couple to the topside of long span ceiling beams of vertically adjoining, modular units stacked below the upper modular units to create a truss system where the physical stress points are shifted from the coupling points of the vertical columns along a neutral horizontal axis to positions at the top and bottom of the truss system further along the vertical columns.
17. The modular system of claim 16, further comprising:
- a plurality of floor truss stitch plate couplers that are configured to secure a first floor truss stitch plate positioned on a first modular unit to a second floor truss stitch plate positioned on a laterally adjacent second modular unit.
18. The modular system of claim 13, further comprising:
- a plurality of column connector plates, wherein the plurality of modular units individually comprise cap plates on top of the vertical columns, and base plates on the bottom of the vertical columns, and
- wherein the cap plates and base plates are configured to attach to the column connector plates such that a cap plate positioned on top of a vertical column on a lower modular unit, can be coupled to a base plate on the bottom of a vertical column of an upper modular unit that is stacked on top of the lower modular unit.
19. The modular system of claim 18, wherein the plurality of column connector plates are configured to allow attachment of four separate modular units including: the cap plates of two vertical columns, each from two separate horizontally adjacent lower modular units and the base plates of two vertical columns, each from two separate horizontally adjacent upper modular units stacked on top of the two lower modular units.
20. A damper system for use in a multistory building with a foundation, the system comprising:
- a damper coupled to the building;
- a plurality of post tension members selected from the group consisting of: post tension rods and post tension cables, the post tension members coupled to the foundation and to the damper;
- wherein the post tension members are configured to transfer energy to the damper when the building experiences deflection event and wherein the damper elastically stores the energy during the event and releases the energy after the event, restoring the building to a substantially neutral equilibrium.
Type: Application
Filed: Aug 26, 2010
Publication Date: Mar 3, 2011
Inventors: Howard Gad (Del Mar, CA), Ryan Gad (San Diego, CA)
Application Number: 12/869,609
International Classification: E04H 1/00 (20060101); E04B 1/98 (20060101); E04C 3/00 (20060101);