U.S. patent application number 12/869609 was filed with the patent office on 2011-03-03 for stackable mid-rise structures.
Invention is credited to Howard Gad, Ryan Gad.
Application Number | 20110047889 12/869609 |
Document ID | / |
Family ID | 43622762 |
Filed Date | 2011-03-03 |
United States Patent
Application |
20110047889 |
Kind Code |
A1 |
Gad; Howard ; et
al. |
March 3, 2011 |
Stackable Mid-Rise Structures
Abstract
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.
Inventors: |
Gad; Howard; (Del Mar,
CA) ; Gad; Ryan; (San Diego, CA) |
Family ID: |
43622762 |
Appl. No.: |
12/869609 |
Filed: |
August 26, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61238958 |
Sep 1, 2009 |
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Current U.S.
Class: |
52/79.1 ;
52/167.1; 52/650.1 |
Current CPC
Class: |
E04B 5/10 20130101; E04B
9/127 20130101; E04B 9/064 20130101; E04H 1/005 20130101; E04B
1/3483 20130101 |
Class at
Publication: |
52/79.1 ;
52/167.1; 52/650.1 |
International
Class: |
E04H 1/00 20060101
E04H001/00; E04B 1/98 20060101 E04B001/98; E04C 3/00 20060101
E04C003/00 |
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.
Description
1.0 BACKGROUND
[0001] 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: [0002] The public's awareness of environmental issues
such as global warming, efficient utilization of scarce natural
resources and a desire to preserve open space. [0003] The growing
trend toward "GREEN" technology in all aspects of our lives
including the appropriate types of future development within our
cities and towns. [0004] The desire by both young and old to live,
work and play in pedestrian oriented, walkable communities designed
around the concept of "Smart Growth." [0005] The economic realities
of today's high energy costs have families rethinking their
priorities by considering smaller, denser housing alternatives in
centralized locations. [0006] 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. [0007] Many
City and County planning agencies now mandate higher density future
development in order to reduce long term service and maintenance
costs.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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 INVENTION
[0012] The 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.
[0013] 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.
3.0 DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates a typical SMR moment frame.
[0015] FIG. 2A shows a SMR modular unit.
[0016] FIG. 2B illustrates a SMR modular unit with structural
framework.
[0017] FIG. 2C shows a SMR modular unit with floor and ceiling
systems.
[0018] FIG. 3A depicts a SMR column connection with a column cap
and base plate attached to the top and bottom of each moment frame
column.
[0019] FIG. 3B illustrates the column cap and base plate
detail.
[0020] FIGS. 3C, 3D and 3E show a column connection that connects
modular units together horizontally and vertically.
[0021] FIG. 4A illustrates a truss stitch plate connecting units
vertically.
[0022] FIG. 4B shows a truss stitch plate viewed from air space
between floor and ceiling systems.
[0023] FIG. 4C depicts truss stitch plates connected together
horizontally using floor truss stitch plate couplers.
[0024] FIG. 5A shows hallways created by adjoining SMR modular
units back to back including mechanical/utility chases.
[0025] FIG. 5B illustrates SMR modular units adjoined using hallway
connector plates to form a full size hallway
[0026] FIG. 6 depicts the roof structure unit that may be connected
to SMR modular units below using the typical column and hallway
connection.
[0027] FIGS. 7A and 7B illustrate a completed 6-story building
comprised of 72 SMR modular units.
[0028] FIG. 7C depicts a completed 4-story building comprised of
SMR modular units with extended bay depths.
[0029] FIG. 7D is a plan view of a completed building comprised of
SMR modular units to create an "L" shaped building.
[0030] FIGS. 8A and 8B depict a post tension system that may be
used within SMR's structural system.
[0031] FIGS. 9A-C are representations of the deflection that an SMR
modular building experiences from a seismic event, and the
correction of the deflection by the post-tension system.
4.0 DETAILED DESCRIPTION
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 4.1 SMR Modular Unit Construction
[0036] 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 FIG. 1. Moment frame floor and ceiling beams (110, 115) are
affixed to two square tube steel columns (105), preferably using
complete joint penetration (CJP) welds to form a structural square
(or rectangle). The width and height of each individual moment
frame (120, 125) will depend on the type of building (residential,
office, school, etc.) and the design parameters selected by the
architect. It would be apparent to one of skill in the art that the
moment frame's (100) size and components may be modified to meet a
particular purpose.
[0037] Now that the moment frame (100) has been described, the base
structure of each modular unit will be discussed with reference to
FIG. 2A. Long span floor and ceiling beams (200, 205) are connected
to moment frames (100) at each end to create a structural steel
rectangular box. These long span wide flange beams are attached to
each moment frame (100) at the column using CJP welds. Joist
hangers (210, 215) are then spot welded to each long span beam's
flange for the attachment of floor/ceiling joists. It should be
noted that the size of long span floor and ceiling beams will be
determined based on design requirements specific to each project
(seismic/wind loads, soil conditions, building size, etc).
[0038] 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.
[0039] FIG. 2B builds on the base structure depicted in FIG. 2A by
adding outlooker extensions (240), hallway extensions (235), floor
joists (220), ceiling joists (225), and resilient channels (230)
completing the structural framework of an SMR modular unit.
Outlooker extensions (240) are composed of steel wide flange beams
and are attached to moment frame columns (100), preferably using
CJP welds. Aside from their primary function of providing a surface
for attaching sheathing and facade, outlookers can also be
lengthened to extend the depth of a module creating additional
interior space or may also be used to create cantilevered balconies
or architectural undulations in the building. Hallway extensions
(235), like outlooker extensions, are composed of steel wide flange
beams and are attached to moment frame columns (100), preferably
using CJP welds. Hallway extensions provide a key connection point
between modular units where two units can be connected back-to-back
to form a full hallway thereby providing additional structural
strength as adjoining modular units behave as one. As an integral
part of SMR's structural system, the hallway connection will be
discussed later in greater detail. Floor joists (220) and ceiling
joists (225), as well as resilient channels (230), are screwed to
joist hangers (210, 215) in order to provide a surface for affixing
each unit's floor and ceiling system.
[0040] FIG. 2C is the same modular unit seen in FIG. 2B, but now
with floor and ceiling systems (245, 250) in place. The floor
system (245) may be composed of a cementitious panelized product
called Fortocrete.RTM., manufactured by USG Corporation (see
http://www.usg.com/usg-fortocrete-structural-panels.html).
Fortocrete structural panels are non-combustible, high-strength,
fiberglass reinforced cement panels designed for use in load
bearing cold-formed steel construction applications. This panelized
floor system is significantly lighter than conventional cast in
place concrete systems and can reduce the seismic design forces of
each floor of a building by as much as 20%. Unlike conventional
sub-flooring systems, like poured in place concrete or light weight
concrete over metal pan decking, Fortocrete has no cure or set
time. The structural panels become the structural sub-floor as soon
as they are fastened. Another feature of Fortocrete panels is that
they cut like wood and fasten to floor joists with conventional
tools (self tapping screws and a screw gun) which significantly
expedites the process of installing SMR's floor system in the
factory. While all of these benefits, as well as a one- and
two-hour fire resistant design, make Fortocrete an ideal product
for SMR's floor system, SMR modular units are also designed to work
with other sub-flooring materials including light weight concrete
over metal pan decking. The ceiling system (250) of each modular
unit may be clad in conventional drywall attached to sound
attenuating resilient channels (230) as needed. Alternatively, drop
down T-bar ceilings with acoustical tile may be used in place of
drywall and resilient channels in certain circumstances.
[0041] 4.2 SMR Modular Unit Connections
[0042] 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.
[0043] FIG. 3A shows a moment frame (100) with a column cap plate
(300) and a column base plate (305) fillet welded to the top and
bottom of each of its columns. The column cap plate (300) and
column base plate (305) are used as points of connection for
adjoining two or more SMR modular units together at the column.
FIG. 3B illustrates the positioning of the moment frame column
(320) within the cap and base plate as well as the location of each
plate's bolt and alignment holes (310, 315). The function of the
bolt and alignment holes is to create points of access where moment
frame columns may be bolted together at adjoining corners using a
column connector plate. FIG. 3C shows a detailed depiction of the
column connector plate (325) and illustrates how the connector
plate's holes match up with the holes of the cap and base plate
(300,305) of each column. The connector plate also includes a hole
(330) through which a post tension rod/cable may be inserted to
provide even more strength in high seismic and wind areas; the post
tension system will be described below. This figure also
illustrates that two columns joined with the column connector
plate, in effect, form one integral column where the neutral axis
(338) is centered between the columns reducing stress on the column
connection plates. FIGS. 3D and 3E illustrate the use of the column
connector plate by showing a modular unit being lowered into place
(340) and connected at adjoining columns to a row of completed
units below (345). In FIG. 3D column connector plates (325) and
column cap plates of completed units below have been bolted
together through their alignment holes (315). This prevents the
column connector plate from slipping during the installation of the
next floor's modular units. In FIG. 3E the modular unit being
lowered into place (340) from FIG. 3D is now attached and has a set
of slip critical bolts sandwiching together the column connector
plate (325), the column cap plate (300) of the unit below, and the
column base plate (305) of the unit being lowered into place (345).
Welding tabs (335) on the column connector plate (325) may also be
utilized to provide additional strength if necessary.
[0044] Another type of connection plate that may be utilized by
SMR's structural system is the floor truss stitch plate. FIG. 4A
illustrates the use of the floor truss stitch plate (400) in
connecting the long span beams of two adjoining units together
vertically thereby creating a strong and efficient floor truss
system (405). Floor truss stitch plates (400) are factory welded to
the bottom of each modular unit's long span floor beams (200) at
intermediate locations. At the jobsite, modular units are lowered
into place and floor truss stitch plates (400) are attached to the
long span ceiling beams (205) of units below, that connection may
use high strength slip critical bolts. With long span floor and
ceiling beams (200, 205) fused together in this manner a truss
system (405) is created. The long span floor and ceiling beams
(200, 205) of each unit act as the truss chords and the floor truss
stitch plates (400) act as the truss webs, creating a floor truss
system with a structural strength that is far greater than the sum
of its parts. With this floor truss system in place, the physical
stress points (413) are shifted from the column connection points
which now lie along the neutral axis (412) to points at the top and
bottom of the truss system away from the neutral axis.
[0045] 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.
FIG. 4B illustrates two adjacent floor truss stitch plates (400)
viewed from the airspace between floor and ceiling systems (410).
As previously discussed, floor truss stitch plates (400) are welded
to the flange of long span floor beams (200) and bolted to the
flange of long span ceiling beams (205). FIG. 4C is an identical
view of the two floor truss stitch plates depicted in FIG. 4B but
now with a floor truss stitch plate coupler (415) holding together
the two adjacent floor truss stitch plates horizontally with,
preferably, high strength slip critical bolts. With the floor truss
system now held together vertically by floor truss stitch plates
(400), and horizontally by floor truss stitch plate couplers (415),
the size of the floor truss system's individual members can be
significantly reduced. The floor truss stitch plate couplers also
help properly align the floor surfaces of adjoining modular units,
creating a level surface to install SMR's Fortocrete floor
system.
[0046] FIG. 5A illustrates yet another unique aspect of SMR's
structural system, the hallway connection. As was discussed
earlier, a hallway extension is included in the structural
framework of each SMR modular unit (see FIG. 2B). A full hallway
(500) is formed when completed SMR modular units (260) are placed
back-to-back with hallway connector plates (515) bonding together
adjacent unit's hallway extensions. The length of hallway
extensions, and thus the width of a full hallway, will depend on
the building type and end user. It should also be noted, that a
hallway may be formed by connecting a modular unit with the hallway
extension, to an adjacent modular unit without such an extension.
Not only can this hallway be used for ingress and egress (510), but
it can also be used to provide services to the building through
mechanical/utility chases (505). FIG. 5B illustrates a detailed
view of the hallway connection described above. In this depiction,
a full hallway has been formed by connecting multiple hallway
extensions (235) together using hallway connector plates (515) and
high strength slip critical bolts. The hallway structure also acts
as a moment frame in a perpendicular direction from those moment
frames that form individual SMR units.
[0047] 4.3 SMR Roof System
[0048] 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. FIG. 6 illustrates multiple angles of a building's top
floor with SMR's roof system (600) attached. The roof system is
attached to the top floor's modular units using the typical column
and hallway connections previously discussed (see FIGS. 3A-3E &
FIGS. 5A-5B for connection detail). The structural members that
make up SMR's roof system (600) are similar to those of SMR modular
units. The roof system has vertical square tube steel parapet
columns (605) connected to horizontal wide flange beams (610, 615)
creating a parapet wall (625) that surrounds the perimeter of the
building. The roof system's diaphragm is also similar to that of a
typical modular unit in that it is composed of Fortocrete panels
(not shown) over steel roof joists (620), the main difference is
that the roof system's floor is sloped toward the parapet wall for
drainage (630).
[0049] 4.4 SMR Structures Completed Building
[0050] 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. FIGS. 7A and 7B
show two different views of a standard 6-story building composed of
72 modular units and a roof system. As shown in FIG. 7A, once
completed, buildings constructed using SMR structures form hallways
(500) with large open bays (700), absent of any interior columns on
either side. The absence of interior columns provides building
owners/designers tremendous flexibility as open bays can be
designed for any conceivable use or configuration. Interior walls
would be constructed with light gauge steel framing and drywall
just like conventional mid-rise buildings; however, most of his
interior work could be done in the factory before SMR modular units
are shipped to the jobsite. FIGS. 7A and 7B also illustrate the
web-like series of moment frames that are created on all 4 sides of
a building constructed using SMR structures. Once connected, the
moment frames in SMR's system are able to act in unison to resist
lateral loads allowing member sizes of individual modular units to
be significantly reduced. This web-like series of moment frames
also gives buildings constructed using the SMR system a significant
amount of structural redundancy. This means that if one or more of
the building's beams fail during a seismic/wind event, there are
many other support beams in close proximity that can carry the load
of the failed beams. This redundancy in having many moment frames
in an SMR structure makes it significantly more advantageous over
conventional construction designs from a seismic/wind load
standpoint.
[0051] Although FIGS. 7A and 7B show buildings with only two units
connected back-to-back at the hallway, it should be noted as shown
in FIG. 7C that extended bay depths (705) can be achieved by simply
adding another row of modular units to either side of the
structure. FIG. 7D shows "L" shaped building may also be achieved
by reconfiguring the placement of modular units and using the
systems and connections described herein. It would be apparent that
other building shapes can be achieved including "T", "O" and
"C".
[0052] 4.5 SMR Post Tension System (High Seismic/Wind)
[0053] In high seismic/wind regions, or as determined by structural
engineers, SMR's post tension system may be utilized to provide
additional structural strength. FIG. 8A illustrates the
installation of SMR's post tension system where a post tension rod
(or cable) (805) has been bolted from the roof to the foundation
(820) as shown in FIG. 8B. Turning back to FIG. 8A, the rod (805)
has been threaded through holes (330--FIG. 3C) in column connector
plates (325) on each floor, attached to an energy dampening device
on the roof (800) and bolted to a connection plate at the
foundation (820). From the foundation to the roof, the building is
now tied down vertically and compressed by with tension rods (or
cables) at various load points throughout the building. In between
each set of parapet columns (605) on the roof, a post tension
energy dampening device (800) is used to create tension and
pre-load the building. The energy dampening device consists of a
post tension rod (or cable) strung through an upper and lower
damper sleeve (815) which encases a rubber (or spring) dampening
mechanism (810). As nuts are tightened on the threaded portion of
the post tension rod (or cable) (805) atop the post tension energy
dampening system (800), the upper and lower damper sleeves (815)
compress around the rubber dampening mechanism (810) and pre-load
the building to a pre-engineered compression. It would be apparent
to one skilled in the art that other damping materials/structures
may be employed including high tension springs for example.
[0054] 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.
[0055] FIGS. 9A-C show a representation of an SMR building (900)
with a typical post-tension rod and energy dampening device in
place (905). FIG. 9A shows the building in the neutral or rest
position where each post-tension rod or cable (905) throughout the
building experiences approximately the same amount of
pre-engineered tension, thus the structure is in equilibrium.
However, when a wind load or seismic event causes the building
(i.e., the columns) to deflect as shown in FIG. 9B, the
post-tension rods or cables (910 & 915) are pulled compressing
the rubber or spring mechanism in the energy dampening device.
After the event, the energy dampening device pulls the building
back into the neutral or at rest position as shown in FIG. 9C. The
benefit of the post-tension rods or cables to bring the structure
back into equilibrium adds structural stability in the event of
seismic and extreme wind loads. The energy absorbing feature of the
SMR post tension system helps return a building back to normal or
equilibrium position with little if any structural damage.
[0056] 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.
[0057] 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.
* * * * *
References