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AISC MARKETING
Structural Steel Framing Solutions For Multi-Story Residential Buildings
STRUCTURAL STEEL
SteelSmart
T O D A Y’S S T E E L: WE MEAN BUSINESS
Increasing Speed and Reducing Costs Improving Quality and Enhancing Occupant Satisfaction
S
use of capital.
Structural steel is the framing system of choice for multi-story residential buildings. The shift to steel will speed up the construction and lower the overall costs of even the most elaborate structures. This translates into faster cash flow and reduced financing fees—resulting in a far more efficient
Are you SteelSmart?
INCREASING SPEED AND REDUCING COSTS
• Faster Construction • Earlier Revenue Generation • Lower Finance Costs • All-Weather Construction • Longer Spans/Fewer Columns • Less Excavation/Fewer Foundations • Achieve Low Floor-to-Floor Heights • Faster Erection • Lower Overall Costs
For buildings that require low floor-to-floor heights, steel exceeds requirements and expectations. These proven framing systems provide columnfree space at lobby levels in hotels, apartments, condominiums and senior residences. In addition, they offer maximum flexibility to accommodate different layout requirements, such as when recessed lighting or other custom condominium details are required.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
• Fabricated to Precise Tolerances in Controlled Environment • Smaller and Fewer Columns/ More Useable Clear Space • More Remodeling/Re-Use Flexibility • Improved Sound Transmission/Attenuation • 100% Recyclable Material
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The Staggered Truss Steel Framing System
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“The engineers decided to ignore everything that was known about typical residential construction in New York City in favor of the staggered truss system.”
Aine M. Brazil, P.E. Managing Principal Thornton-Tomasetti Engineers New York, NY
The 14-story Embassy Suites Hotel was part of an extensive mixed-use project in New York City. It originally was conceived as a cast-in-place concrete system— a design that proved to be excessively expensive. The innovative Staggered Truss Steel Framing System was chosen because it offers virtually all the advantages of flat-slab concrete construction at a significantly lower cost. Also, it allowed the hotel to meet its 8’-9” floor-to-floor height requirements. The lighter weight steel frame also contributed to significant cost savings on the pile foundation system.
INCREASING SPEED AND REDUCING COSTS
The decision to use a staggered truss system on the Embassy Suites project was partly a financial one. Steel’s 20% weight advantage over heavier concrete systems resulted in lower foundation costs, reduced seismic loads, and overall savings of $2.5 million. The low floor-tofloor dimensions further reduced costs by reducing the overall building height and lowering its heating and cooling costs.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The staggered truss system dramatically improved the hotel’s layout by eliminating interior columns to create more clear open space. This open space provided more aesthetic design options for lobby, ballroom, restaurant and retail activities, and added to the inviting ambiance of the space as well. In the portion of the structure designated for retail, steel framing provided the ultimate in flexibility. It permitted easy modification of the main shopping areas and simplified the process of changing individual tenant spaces.
Precast Plank Vierendeel Openings for Corridors The staggered truss system consists of a storyhigh truss that spans the entire width of the building. The trusses alternate from floor to floor with the long axis of one truss mid-span between the trusses on the floors immediately above and below. The system works in harmony with precast plank that provides a smooth floor and ceiling while achieving the desired low floor-to-floor height. The composite truss and plank system provides a safe and efficient structural system that resists both gravity and lateral loads. 2
Story-High Ł Truss
Column-Free Space at Lower Level
The Staggered Truss Steel Framing System Provided Four Key Benefits: • Significant Cost Savings Due to the Lighter Frame and Fewer Foundations • Achieved the Desired Low Floor-To-Floor Heights • Realized Semi-Finished Floor and Ceiling in One Operation • Provided More Column-Free Open Space at Building Base
The Embassy Suites Hotel in New York, New York.
Project: Embassy Suites Hotel Location: New York, NY Owner/Developer: Forest City Ratner Companies Architect: Perkins Eastman Architects, P.C.
Structural Engineer: Thornton-Tomasetti Engineers Construction Manager: Bovis Lend Lease Fabricator: Helmark Steel
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The Girder-Slab Structural Steel Framing System
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“Not only did the project prove that structural steel can be used effectively in multifamily residential construction, but it provided an economical low floor-to-floor height building that was built quickly under cold weather conditions.”
Peter A. Naccarato, P.E. Principal O’Donnell & Naccarato, Inc. Philadelphia, PA
Drexel University found itself in a precarious position. The prestigious Philadelphia institution had a set of plans for a new dormitory building, and less than a year in which to implement them. The challenge was to find a construction system that would guarantee completion of the dormitory by the appointed opening date. The original plans called for a structural scheme consisting of precast hollow core slabs supported by masonry-bearing walls. Since a pile foundation had to be installed first, this would severely hamper the scheduled construction of masonry-bearing wall system. Because the superstructure, as designed, could not be built within the allotted time frame, the University solicited proposals on alternative systems. After review, the Girder-Slab Structural Steel Framing System was selected for its ability to be constructed with speed and economy.
INCREASING SPEED AND REDUCING COSTS
This system can be constructed quickly and economically despite time restraints and inclement weather. Drexel University selected the girder-slab system because it was a system that met the 8’-8” floorto-floor height requirements. The inplace cost of the girder-slab system proved to be less than the original masonry-bearing wall design. In addition, the lighter steel frame provided additional savings by reducing the amount of costly deep foundation work. Working through freezing winter temperatures, the entire Drexel University dormitory superstructure was erected in only 31 days.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The girder-slab system provided two distinct advantages for the building occupants. First, structural steel offered more flexibility in the architectural layout by eliminating immovable masonry bearing walls. Second, the steel frame uses smaller columns than a comparable concrete system. These benefits resulted in more flexibility and options in the floor layout. In addition, the choice of structural steel allowed for varying room sizes and easier expansion to meet the diverse and changing needs of university housing.
Above: Installation of Precast Plank. Right: Drexel University Dormitory under Construction.
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The Girder-Slab Steel Framing System Provided Five Key Benefits: • Economical Steel and Plank Design for Low Floor-to-Floor Height Buildings
8" Grout
8" Precast Hollow-core Slab
• Quality Plank Provided Floor and Ceiling in One Operation • Frame Erected Through Freezing Temperatures in 31 Days • Lighter Steel Frame Resulted in Fewer Pile Foundations • UL K 912 Provided a Low-Cost, 2-Hour Fire Rating
T.O. Slab
D-Beam
Girder-slab is a steel and precast plank design that is a practical alternative to the plank and bearing wall system. This steel framing system involves placing the interior structural steel girder within the plane of the precast plank. One of its primary benefits is that it accommodates low floor-tofloor height requirements while avoiding MEP interference problems. It is also a competitive alternative to cast-in-place flat plate concrete. In fact, because recent seismic code revisions increased lateral loads, the bearing wall type of construction is no longer considered economical.
Project: Drexel University Dormitory Location: Philadelphia, PA Owner/Developer: Drexel University Architect: BHKR Associates Structural Engineer: O’Donnell & Naccarato General Contractor: P. Agnes Construction Company Fabricator: Fisher Steel, Inc.
The Completed Drexel University Dormitory in Philadelphia, Pennsylvania.
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In-Wall Beam Structural Steel Framing System
“The entire building foundation and superstructure was constructed in approximately 12 months.”
Christopher P. Milano, P.E. McNamara/Salvia, Inc. Boston, MA
Project: Trinity Place Residential Tower Location: Boston, MA Owner: Raymond Property Company Architect: Childs Bertman Tseckares (CBT) Structural Engineer: McNamara/Salvia, Inc. General Contractor: Turner Construction Company Fabricator: Cives Steel Company
Trinity Place Residential Tower in Boston, Massachusetts.
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Trinity Place was one of the first multistory residential projects to be built in Boston in the past 10 years. However, the location chosen for the project was not without its challenges. The luxury condominium tower was situated in a crowded area on a very compact site. It was an ideal opportunity for steel to show its strength.
INCREASING SPEED AND REDUCING COSTS
The entire foundation of the building and the 20-story structure sitting on top of it were constructed in approximately 12 months. An innovative framing layout was used based on a 14’ x 28’ module with the steel deck spanning 14’. This design minimized the number of floor beams needed, and allowed the raising of ceiling heights in an otherwise tight floor-to-floor space. Fewer members also meant faster fabrication and erection of the steel.
The use of 16-gauge steel deck eliminated the need for temporary shoring during concrete placement. The overall framing design accelerated the erection, decking, detailing and concrete slab placement. Additionally, the reduction in the number of floor beams kept overall steel weight, fabrication and erection costs to a minimum.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The In-Wall Beam Structural Steel Framing in Trinity Place eliminated fixed shear walls for increased resistance to seismic forces. This, in turn, allowed tenants maximum flexibility in modifying the layouts of their individual condominiums. The 8’-10” ceiling height is consistent with what is demanded in luxury condominiums, while the 12” space above the ceiling permitted recessed lighting and other custom features.
Trinity Place under Construction.
This In-Wall Beam Structural Steel Framing System Provided Four Key Benefits: • Increased the Speed of Construction • Achieved the Desired Floor-to-Floor Height While Economizing on Overall Building Height • Allowed Maximum Owner/Tenant Flexibility by Elimination of Fixed Concrete Shear Walls Normally Required to Resist Earthquake Forces • Permitted Installation of Recessed Lighting and Other Custom Condominium Features
This in-wall beam system was designed with structural steel framing on a 14’ x 28’ grid. It has a 3” x 16-gauge composite metal deck spanning the full 14’. This feature kept the number of floor beams to a minimum. In addition, it allowed for higher ceilings while keeping the overall building height at a minimum. The typical floor-to-floor height was 10’-4” with a ceiling height of 8’-10” between the floor beams.
Steel Beam Hidden in Interior Wall
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In-Wall Beam Structural Steel Framing System
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“Certain techniques, applied to structural steel framing systems to achieve the benefits of low floor-to-floor heights, can make structural steel costs competitive with concrete.”
Minhaj Kirmani, PhD, P.E. Weidlinger Associates, Inc. Cambridge, MA
The proximity of the 18-story Seaport Hotel in Boston to nearby Logan Airport posed a significant challenge. Because of FAA-imposed zoning regulations and height restrictions on the building, the hotel’s developers wanted to achieve the maximum number of guest rooms within the budget limit. Accordingly, the design and construction team sought to maximize the number of floors and minimize the floor-to-floor height without diminishing the picturesque view for hotel guests.
INCREASING SPEED AND REDUCING COSTS
Structural steel provided the perfect solution to the Seaport Hotel’s framing problems because of its low cost and scheduling advantages. This system permitted the creation of additional hotel space without changing the building’s overall height. The repetitive fixed layout of the guest rooms provided convenient locations for “burying” the floor beams, as well as lateral bracing for the structure in the party walls.
This In-Wall Beam Structural Steel Framing System Provided Three Key Benefits: • Better Overall Economy with Low Floor-to-Floor Heights • More Open Ballroom Space at Public Levels with Long-Span Transfer Girders • Faster Construction Saved Time and Reduced Costs
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In addition, passing utilities through beam web penetrations helped reduce the overall depth of construction. To further accelerate the building process, the project team used a technique known as “up-up” construction. Heavy, unbraced 35’-long columns extended from the three-level, belowgrade parking structure up through the ground floor structural steel framing. This allowed the above-grade construction to continue at the same time that the below-grade parking garage was being completed, reducing the construction schedule significantly.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The Seaport Hotel, situated in a popular tourist area, wanted to provide its guests with grand views of the Boston skyline and waterfront. While the higherthan-typical ceiling heights remained within the overall building height restrictions, they accommodated larger windows in the guest rooms to dramatically enhance the views. The choice of structural steel facilitated the use of 65’ transfer girders that allowed for open ballroom space at the lower level as well.
Ceiling 8'-6" Floor-to-Ceiling 9'-0" Floor-to-Floor
Guest Room
Floor Level
Project: Seaport Hotel Location: Boston, MA Owner: Pembroke Real Estate, Inc. Architect: The Stubbins Associates Structural Engineer: Weidlinger Associates, Inc. General Contractor: AMEC (formerly Morse-Diesel) Fabricator: Cives Steel Company
This structural system used wide flange beams located within the demising walls between the hotel rooms, with only a composite slab and the deck spanning between beams. This permitted the framing system to achieve a floor-to-floor height of 9’-0” with an 8’-6” ceiling height on the upper room levels. Typical floor construction consists of 5-1/2” composite slab on metal deck. The slab spans the full width of a room between floor beams centered on the guest room partition walls. The ceiling within the guest rooms is supported against the underside of the deck to achieve an 8’-6” floor-to-ceiling height.
The Seaport Hotel in Boston, Massachusetts.
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Beam & Open Web Joist Structural Steel Framing System
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“The cost of the structural steel system was very competitive in price and allowed us to keep the condominium costs down and pass along the savings to our home buyers.”
Thomas Roszak Roszak/ADC Evanston, IL
Chicago Avenue Place, a new multistory luxury condominium in suburban Chicago, benefited from the use of a Beam & Open Web Joist Structural Steel Framing System. This system provided cost-effectiveness for the design and development team, and flexibility for the owners. It allowed for larger, free-flowing expanses of space and a notable reduction in the transmission of sound between units as well. Such attributes are highly desirable—if not mandatory—among discriminating condominium owners.
This Beam & Open Web Joist Structural Steel Framing System Provided Five Key Benefits: • Faster Construction • Flexibility to Customize Floor Plan with Large Steel Grid and Non-Load-Bearing Walls • Superior Sound Attenuation • Space to Install Recessed Lighting and Other Custom Details • Provided Space for MEP Systems, while Reducing Floor-to-Floor Heights
Chicago Avenue Place Condominiums in Evanston, Illinois.
This beam & joist framing system utilized steel beams, columns, metal joists and metal decking. The structural grid is based on the parking layout of the basement and first floor levels. This structural grid continues on the upper levels to the condominiums.
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INCREASING SPEED AND REDUCING COSTS
The beam & joist system used in Chicago Avenue Place resulted in the accelerated erection of the building and permitted the owner to complete the condominium units more quickly than with cast-in-place concrete. This, in turn, lowered financing expenses significantly. The total price tag for the steel system was very competitive and kept condominium costs down so the savings could be passed on to the owner or occupants.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
As an added benefit of the steel framing system, owners gained the ability to customize their condominiums simply by moving or eliminating the non-loadbearing partitions.
Additionally, the joist structure and gypsum board enclosure allowed for installation of recessed lighting and other custom condominium features.
Project: Chicago Avenue Place Condominiums Location: Evanston, IL
Developer: Roszak/ADC Design/Architect: Roszak/ADC Associate Architect: Wallin/Gomez
Structural Engineer: Samartano & Co. General Contractor: Roszak/ADC Fabricator: Rockford Ornamental Iron
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Integrated Steel-Precast Concrete Composite Framing System
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“We wanted to take advantage of the typically faster construction with structural steel and make it work for a hotel project. We were able to achieve this by combining the best features of structural steel with a precast, prestressed floor system.”
Gary Chock, P.E. Martin & Chock, Inc. Honolulu, HI
The 24-story Hilton Hawaiian Village Kalia Tower, Waikiki’s first all steelframed high-rise, was designed with an innovative composite construction system that achieved breakthrough economy and speed. The 300’-high, 450-room hotel features a 40’-tall lobby area and a 2-story deep bridge connecting to the adjacent Coral Ballroom and meeting rooms. The top of the bridge functions as a recreation deck, which includes a sculpturally-formed swimming pool.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
As a luxury hotel, the need to create a more spacious feeling in the guest rooms was of paramount importance. This goal was achieved with an 8’-6” ceiling height while still keeping the overall floor-to-floor height at 9’. The structural steel system also allowed builders to lay out the steel framing so that most of the beams fell within the demising walls. As a result, the owner realized the economies that come with keeping overall building heights at a minimum.
Project: Hilton Hawaiian Village Kalia Tower Location: Waikiki, Hawaii Owner: Hilton Hotels Corporation Construction Manager: Construction Management & Development, Inc. Architect: Wimberly Allison Tong & Goo Structural Engineer: Martin & Chock, Inc. General Contractor: Hawaiian Dredging Construction Company Fabricator: Samsung Heavy Industries
INCREASING SPEED AND REDUCING COSTS
The combination of structural steel and precast concrete slab was selected because it was faster to construct and the structural and foundation cost was 30% lower than competing concrete systems. Several factors contributed to the significant cost savings. The lighter weight of the steel structure was a big advantage on a site with poor soil conditions. Drilled shafts, rather than driven piles, saved an initial $1 million, and a lighter building resulted in $1.25 million in additional foundation savings. The light composite steel-braced frame structure, with 6” thick precast concrete plank and concrete-filled steel box columns in designated areas, saved $1.75 million over a conventional posttensioned concrete structure. The building boasts a semi-finished floor and ceiling created in one operation. This permitted the owner to realize a 5 to 6 month quicker construction schedule. Close interaction between the architects and structural engineers during the design process allowed the structural system to be optimized for cost and weight, and brought the project within the $64 million construction budget. So dramatic were the results of this joint effort that the owner was able to add two floors to the tower without increasing the original steel tonnage. All of these benefits were achieved while satisfying the architectural requirements of a luxury hotel.
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This Steel Composite System Provided Five Key Benefits: • Early Project Completion • Lower Cost than Concrete Systems
17'-8" 14'-3" 204'-0" 13 Spaces @ 13'-6" 14'-3"
• Low Floor-to-Floor Heights • Semi-Finished Floor and Ceiling in One Operation • Higher Ceilings in Guest Rooms Without Increasing Floor-toFloor Heights
PLANKS
25'-0"
DECKING
17'-8"
PLANKS
The tower utilized a composite system composed of steel beams with a 6”-thick precast, prestressed concrete plank in the guest rooms, and metal deck with beams in the corridors. The lateral system was a braced frame with composite box columns filled with concrete.
Far Left: Hilton Hawaiian Village Kalia Tower under Construction. Left: The Completed Hilton Hawaiian Village Kalia Tower in Waikiki, Hawaii.
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The Staggered Truss Structural Steel Framing System
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“Analysis of other framing systems produced strong evidence that the staggered truss system offered a significant number of economic advantages.”
Neil Wexler, P.E., P.C. Wexler and Associates New York, NY
The 6-story, 210-room Mystic Marriott Hotel & Spa overlooks Connecticut’s scenic Groton Reservoir. The hotel was designed to incorporate the scale and imagery of classic New England architecture, and its appearance is reminiscent of the great hotels from the turn of the century. The design team considered several construction systems in the initial phase of the project, including traditional post & beam. However, the Staggered Truss System was selected because it offered, among other distinct advantages, the most flexibility, most reasonable construction costs, and significant design flexibility.
The Staggered Truss Steel Framing System Provided Four Key Benefits: • Fewer Columns Allowed the Creation of More Flexible and Efficient Floor Plans • The lower Number of Columns Reduced Weight and Costs • Faster, All-weather Erection Reduced Time and Saved Money • High Quality Plank Provided a Finished Floor and Ceiling Without the Added Expense of Topping
The Mystic Marriott Hotel & Spa in Groton, Connecticut.
Vierendeel Opening for Corridors
Trusses Span the Entire Building Width
Trusses Are Staggered from Floor-to-Floor
This cross-section depicts the staggered truss framing layout for the Mystic Marriott. The trusses were set at 28’ on center, and designed with 10”-deep, wide-flange chords. The plank is 8” thick and the web members are tubular. Vierendeel panels were incorporated at the corridor and at designated points between rooms. All truss-to-column connections were bolted. The lateral loads are resisted by the staggered trusses as braced frames, allowing the plank floors to act as diaphragms. A rigid connection between the trusses and the plank was achieved with a modified grout that was pumped into plank cores. Nelson studs were welded to the truss chords to transfer the diaphragm forces between trusses.
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INCREASING SPEED AND REDUCING COSTS
The staggered truss system allowed for faster erection than traditional post & beam, reducing the total cost of the superstructure. Though construction took place during the winter months, the majority of the structure was completed expeditiously. Additional savings accrued because the building required fewer columns and less steel tonnage. No transfer girders were required at the second floor over the hotel’s extensive public spaces. This translated into lower costs for the fabrication of the steel, and foundation savings due to the reduced necessity for footings. The truss system used precast plank, which provided a finished ceiling and eliminated the need and expense of gypsum board.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The staggered truss steel framing system features fewer columns overall, which enabled the design team to create the most flexible and efficient floor plans possible. The public areas within the hotel benefited the most. The 10,000 square foot ballroom, for example, is
completely column-free. This open layout permitted unobstructed site lines for guests, as well as a variety of room configurations that maximized occupancy. The restaurant and spa also benefited from fewer columns by allowing designers to place tables, service areas and treatment rooms in the most efficient manner.
Project: Mystic Marriott Hotel & Spa Location: Groton, CT Owner: Waterford Hotel Group Architect: Brennan Beer Gorman/ Architects, L.L.P. Structural Engineer: Wexler and Associates General Contractor: Wolman Construction
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Advantage Steel: Adding Value to Multi-Story Residential Buildings
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requirements.
AISC MARKETING INDUSTRY SUPPORT
• Specifications • Publications • www.aisc.org
Low cost. Strength. Durability. Design Flexibility. Adaptability. Recyclability. These advantages make structural steel an ideal material choice for hotels, apartments, condominiums and senior residences. Whether the issue is economy, speed or quality, structural steel can meet or exceed the most demanding project
The American Institute of Steel Construction (AISC) is a not-for-profit technical institute and trade association serving the structural steel design and construction community in the U.S. AISC Marketing, a wholly-owned subsidiary supported by the AISC Steel Solutions Center, will help you take a serious look at the structural framing system of your next multi-story residential building. AISC’s Steel Solutions Center and Regional Engineers are available throughout the U.S. to provide preliminary design assistance, comparative cost estimates, and review with you the benefits of using steel to your advantage.
• Steel Solutions Center Assistance • Technical Assistance • Engineering & Research
• University Educational Programs • Steel Fabricator Certification Program • Steel Erector Certification Program • Design Awards for Architects and Engineers • Continuing Education for Architects, Engineers and Structural Steel Fabricators
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Structural Steel Framing Solutions For Multi-Story Residential Buildings
STRUCTURAL STEEL
SteelSmart
T O D A Y’S S T E E L: WE MEAN BUSINESS
Increasing Speed and Reducing Costs Improving Quality and Enhancing Occupant Satisfaction
S
use of capital.
Structural steel is the framing system of choice for multi-story residential buildings. The shift to steel will speed up the construction and lower the overall costs of even the most elaborate structures. This translates into faster cash flow and reduced financing fees—resulting in a far more efficient
Are you SteelSmart?
INCREASING SPEED AND REDUCING COSTS
• Faster Construction • Earlier Revenue Generation • Lower Finance Costs • All-Weather Construction • Longer Spans/Fewer Columns • Less Excavation/Fewer Foundations • Achieve Low Floor-to-Floor Heights • Faster Erection • Lower Overall Costs
For buildings that require low floor-to-floor heights, steel exceeds requirements and expectations. These proven framing systems provide columnfree space at lobby levels in hotels, apartments, condominiums and senior residences. In addition, they offer maximum flexibility to accommodate different layout requirements, such as when recessed lighting or other custom condominium details are required.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
• Fabricated to Precise Tolerances in Controlled Environment • Smaller and Fewer Columns/ More Useable Clear Space • More Remodeling/Re-Use Flexibility • Improved Sound Transmission/Attenuation • 100% Recyclable Material
1
The Staggered Truss Steel Framing System
T
“The engineers decided to ignore everything that was known about typical residential construction in New York City in favor of the staggered truss system.”
Aine M. Brazil, P.E. Managing Principal Thornton-Tomasetti Engineers New York, NY
The 14-story Embassy Suites Hotel was part of an extensive mixed-use project in New York City. It originally was conceived as a cast-in-place concrete system— a design that proved to be excessively expensive. The innovative Staggered Truss Steel Framing System was chosen because it offers virtually all the advantages of flat-slab concrete construction at a significantly lower cost. Also, it allowed the hotel to meet its 8’-9” floor-to-floor height requirements. The lighter weight steel frame also contributed to significant cost savings on the pile foundation system.
INCREASING SPEED AND REDUCING COSTS
The decision to use a staggered truss system on the Embassy Suites project was partly a financial one. Steel’s 20% weight advantage over heavier concrete systems resulted in lower foundation costs, reduced seismic loads, and overall savings of $2.5 million. The low floor-tofloor dimensions further reduced costs by reducing the overall building height and lowering its heating and cooling costs.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The staggered truss system dramatically improved the hotel’s layout by eliminating interior columns to create more clear open space. This open space provided more aesthetic design options for lobby, ballroom, restaurant and retail activities, and added to the inviting ambiance of the space as well. In the portion of the structure designated for retail, steel framing provided the ultimate in flexibility. It permitted easy modification of the main shopping areas and simplified the process of changing individual tenant spaces.
Precast Plank Vierendeel Openings for Corridors The staggered truss system consists of a storyhigh truss that spans the entire width of the building. The trusses alternate from floor to floor with the long axis of one truss mid-span between the trusses on the floors immediately above and below. The system works in harmony with precast plank that provides a smooth floor and ceiling while achieving the desired low floor-to-floor height. The composite truss and plank system provides a safe and efficient structural system that resists both gravity and lateral loads. 2
Story-High Ł Truss
Column-Free Space at Lower Level
The Staggered Truss Steel Framing System Provided Four Key Benefits: • Significant Cost Savings Due to the Lighter Frame and Fewer Foundations • Achieved the Desired Low Floor-To-Floor Heights • Realized Semi-Finished Floor and Ceiling in One Operation • Provided More Column-Free Open Space at Building Base
The Embassy Suites Hotel in New York, New York.
Project: Embassy Suites Hotel Location: New York, NY Owner/Developer: Forest City Ratner Companies Architect: Perkins Eastman Architects, P.C.
Structural Engineer: Thornton-Tomasetti Engineers Construction Manager: Bovis Lend Lease Fabricator: Helmark Steel
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The Girder-Slab Structural Steel Framing System
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“Not only did the project prove that structural steel can be used effectively in multifamily residential construction, but it provided an economical low floor-to-floor height building that was built quickly under cold weather conditions.”
Peter A. Naccarato, P.E. Principal O’Donnell & Naccarato, Inc. Philadelphia, PA
Drexel University found itself in a precarious position. The prestigious Philadelphia institution had a set of plans for a new dormitory building, and less than a year in which to implement them. The challenge was to find a construction system that would guarantee completion of the dormitory by the appointed opening date. The original plans called for a structural scheme consisting of precast hollow core slabs supported by masonry-bearing walls. Since a pile foundation had to be installed first, this would severely hamper the scheduled construction of masonry-bearing wall system. Because the superstructure, as designed, could not be built within the allotted time frame, the University solicited proposals on alternative systems. After review, the Girder-Slab Structural Steel Framing System was selected for its ability to be constructed with speed and economy.
INCREASING SPEED AND REDUCING COSTS
This system can be constructed quickly and economically despite time restraints and inclement weather. Drexel University selected the girder-slab system because it was a system that met the 8’-8” floorto-floor height requirements. The inplace cost of the girder-slab system proved to be less than the original masonry-bearing wall design. In addition, the lighter steel frame provided additional savings by reducing the amount of costly deep foundation work. Working through freezing winter temperatures, the entire Drexel University dormitory superstructure was erected in only 31 days.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The girder-slab system provided two distinct advantages for the building occupants. First, structural steel offered more flexibility in the architectural layout by eliminating immovable masonry bearing walls. Second, the steel frame uses smaller columns than a comparable concrete system. These benefits resulted in more flexibility and options in the floor layout. In addition, the choice of structural steel allowed for varying room sizes and easier expansion to meet the diverse and changing needs of university housing.
Above: Installation of Precast Plank. Right: Drexel University Dormitory under Construction.
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The Girder-Slab Steel Framing System Provided Five Key Benefits: • Economical Steel and Plank Design for Low Floor-to-Floor Height Buildings
8" Grout
8" Precast Hollow-core Slab
• Quality Plank Provided Floor and Ceiling in One Operation • Frame Erected Through Freezing Temperatures in 31 Days • Lighter Steel Frame Resulted in Fewer Pile Foundations • UL K 912 Provided a Low-Cost, 2-Hour Fire Rating
T.O. Slab
D-Beam
Girder-slab is a steel and precast plank design that is a practical alternative to the plank and bearing wall system. This steel framing system involves placing the interior structural steel girder within the plane of the precast plank. One of its primary benefits is that it accommodates low floor-tofloor height requirements while avoiding MEP interference problems. It is also a competitive alternative to cast-in-place flat plate concrete. In fact, because recent seismic code revisions increased lateral loads, the bearing wall type of construction is no longer considered economical.
Project: Drexel University Dormitory Location: Philadelphia, PA Owner/Developer: Drexel University Architect: BHKR Associates Structural Engineer: O’Donnell & Naccarato General Contractor: P. Agnes Construction Company Fabricator: Fisher Steel, Inc.
The Completed Drexel University Dormitory in Philadelphia, Pennsylvania.
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In-Wall Beam Structural Steel Framing System
“The entire building foundation and superstructure was constructed in approximately 12 months.”
Christopher P. Milano, P.E. McNamara/Salvia, Inc. Boston, MA
Project: Trinity Place Residential Tower Location: Boston, MA Owner: Raymond Property Company Architect: Childs Bertman Tseckares (CBT) Structural Engineer: McNamara/Salvia, Inc. General Contractor: Turner Construction Company Fabricator: Cives Steel Company
Trinity Place Residential Tower in Boston, Massachusetts.
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Trinity Place was one of the first multistory residential projects to be built in Boston in the past 10 years. However, the location chosen for the project was not without its challenges. The luxury condominium tower was situated in a crowded area on a very compact site. It was an ideal opportunity for steel to show its strength.
INCREASING SPEED AND REDUCING COSTS
The entire foundation of the building and the 20-story structure sitting on top of it were constructed in approximately 12 months. An innovative framing layout was used based on a 14’ x 28’ module with the steel deck spanning 14’. This design minimized the number of floor beams needed, and allowed the raising of ceiling heights in an otherwise tight floor-to-floor space. Fewer members also meant faster fabrication and erection of the steel.
The use of 16-gauge steel deck eliminated the need for temporary shoring during concrete placement. The overall framing design accelerated the erection, decking, detailing and concrete slab placement. Additionally, the reduction in the number of floor beams kept overall steel weight, fabrication and erection costs to a minimum.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The In-Wall Beam Structural Steel Framing in Trinity Place eliminated fixed shear walls for increased resistance to seismic forces. This, in turn, allowed tenants maximum flexibility in modifying the layouts of their individual condominiums. The 8’-10” ceiling height is consistent with what is demanded in luxury condominiums, while the 12” space above the ceiling permitted recessed lighting and other custom features.
Trinity Place under Construction.
This In-Wall Beam Structural Steel Framing System Provided Four Key Benefits: • Increased the Speed of Construction • Achieved the Desired Floor-to-Floor Height While Economizing on Overall Building Height • Allowed Maximum Owner/Tenant Flexibility by Elimination of Fixed Concrete Shear Walls Normally Required to Resist Earthquake Forces • Permitted Installation of Recessed Lighting and Other Custom Condominium Features
This in-wall beam system was designed with structural steel framing on a 14’ x 28’ grid. It has a 3” x 16-gauge composite metal deck spanning the full 14’. This feature kept the number of floor beams to a minimum. In addition, it allowed for higher ceilings while keeping the overall building height at a minimum. The typical floor-to-floor height was 10’-4” with a ceiling height of 8’-10” between the floor beams.
Steel Beam Hidden in Interior Wall
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In-Wall Beam Structural Steel Framing System
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“Certain techniques, applied to structural steel framing systems to achieve the benefits of low floor-to-floor heights, can make structural steel costs competitive with concrete.”
Minhaj Kirmani, PhD, P.E. Weidlinger Associates, Inc. Cambridge, MA
The proximity of the 18-story Seaport Hotel in Boston to nearby Logan Airport posed a significant challenge. Because of FAA-imposed zoning regulations and height restrictions on the building, the hotel’s developers wanted to achieve the maximum number of guest rooms within the budget limit. Accordingly, the design and construction team sought to maximize the number of floors and minimize the floor-to-floor height without diminishing the picturesque view for hotel guests.
INCREASING SPEED AND REDUCING COSTS
Structural steel provided the perfect solution to the Seaport Hotel’s framing problems because of its low cost and scheduling advantages. This system permitted the creation of additional hotel space without changing the building’s overall height. The repetitive fixed layout of the guest rooms provided convenient locations for “burying” the floor beams, as well as lateral bracing for the structure in the party walls.
This In-Wall Beam Structural Steel Framing System Provided Three Key Benefits: • Better Overall Economy with Low Floor-to-Floor Heights • More Open Ballroom Space at Public Levels with Long-Span Transfer Girders • Faster Construction Saved Time and Reduced Costs
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In addition, passing utilities through beam web penetrations helped reduce the overall depth of construction. To further accelerate the building process, the project team used a technique known as “up-up” construction. Heavy, unbraced 35’-long columns extended from the three-level, belowgrade parking structure up through the ground floor structural steel framing. This allowed the above-grade construction to continue at the same time that the below-grade parking garage was being completed, reducing the construction schedule significantly.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The Seaport Hotel, situated in a popular tourist area, wanted to provide its guests with grand views of the Boston skyline and waterfront. While the higherthan-typical ceiling heights remained within the overall building height restrictions, they accommodated larger windows in the guest rooms to dramatically enhance the views. The choice of structural steel facilitated the use of 65’ transfer girders that allowed for open ballroom space at the lower level as well.
Ceiling 8'-6" Floor-to-Ceiling 9'-0" Floor-to-Floor
Guest Room
Floor Level
Project: Seaport Hotel Location: Boston, MA Owner: Pembroke Real Estate, Inc. Architect: The Stubbins Associates Structural Engineer: Weidlinger Associates, Inc. General Contractor: AMEC (formerly Morse-Diesel) Fabricator: Cives Steel Company
This structural system used wide flange beams located within the demising walls between the hotel rooms, with only a composite slab and the deck spanning between beams. This permitted the framing system to achieve a floor-to-floor height of 9’-0” with an 8’-6” ceiling height on the upper room levels. Typical floor construction consists of 5-1/2” composite slab on metal deck. The slab spans the full width of a room between floor beams centered on the guest room partition walls. The ceiling within the guest rooms is supported against the underside of the deck to achieve an 8’-6” floor-to-ceiling height.
The Seaport Hotel in Boston, Massachusetts.
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Beam & Open Web Joist Structural Steel Framing System
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“The cost of the structural steel system was very competitive in price and allowed us to keep the condominium costs down and pass along the savings to our home buyers.”
Thomas Roszak Roszak/ADC Evanston, IL
Chicago Avenue Place, a new multistory luxury condominium in suburban Chicago, benefited from the use of a Beam & Open Web Joist Structural Steel Framing System. This system provided cost-effectiveness for the design and development team, and flexibility for the owners. It allowed for larger, free-flowing expanses of space and a notable reduction in the transmission of sound between units as well. Such attributes are highly desirable—if not mandatory—among discriminating condominium owners.
This Beam & Open Web Joist Structural Steel Framing System Provided Five Key Benefits: • Faster Construction • Flexibility to Customize Floor Plan with Large Steel Grid and Non-Load-Bearing Walls • Superior Sound Attenuation • Space to Install Recessed Lighting and Other Custom Details • Provided Space for MEP Systems, while Reducing Floor-to-Floor Heights
Chicago Avenue Place Condominiums in Evanston, Illinois.
This beam & joist framing system utilized steel beams, columns, metal joists and metal decking. The structural grid is based on the parking layout of the basement and first floor levels. This structural grid continues on the upper levels to the condominiums.
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INCREASING SPEED AND REDUCING COSTS
The beam & joist system used in Chicago Avenue Place resulted in the accelerated erection of the building and permitted the owner to complete the condominium units more quickly than with cast-in-place concrete. This, in turn, lowered financing expenses significantly. The total price tag for the steel system was very competitive and kept condominium costs down so the savings could be passed on to the owner or occupants.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
As an added benefit of the steel framing system, owners gained the ability to customize their condominiums simply by moving or eliminating the non-loadbearing partitions.
Additionally, the joist structure and gypsum board enclosure allowed for installation of recessed lighting and other custom condominium features.
Project: Chicago Avenue Place Condominiums Location: Evanston, IL
Developer: Roszak/ADC Design/Architect: Roszak/ADC Associate Architect: Wallin/Gomez
Structural Engineer: Samartano & Co. General Contractor: Roszak/ADC Fabricator: Rockford Ornamental Iron
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Integrated Steel-Precast Concrete Composite Framing System
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“We wanted to take advantage of the typically faster construction with structural steel and make it work for a hotel project. We were able to achieve this by combining the best features of structural steel with a precast, prestressed floor system.”
Gary Chock, P.E. Martin & Chock, Inc. Honolulu, HI
The 24-story Hilton Hawaiian Village Kalia Tower, Waikiki’s first all steelframed high-rise, was designed with an innovative composite construction system that achieved breakthrough economy and speed. The 300’-high, 450-room hotel features a 40’-tall lobby area and a 2-story deep bridge connecting to the adjacent Coral Ballroom and meeting rooms. The top of the bridge functions as a recreation deck, which includes a sculpturally-formed swimming pool.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
As a luxury hotel, the need to create a more spacious feeling in the guest rooms was of paramount importance. This goal was achieved with an 8’-6” ceiling height while still keeping the overall floor-to-floor height at 9’. The structural steel system also allowed builders to lay out the steel framing so that most of the beams fell within the demising walls. As a result, the owner realized the economies that come with keeping overall building heights at a minimum.
Project: Hilton Hawaiian Village Kalia Tower Location: Waikiki, Hawaii Owner: Hilton Hotels Corporation Construction Manager: Construction Management & Development, Inc. Architect: Wimberly Allison Tong & Goo Structural Engineer: Martin & Chock, Inc. General Contractor: Hawaiian Dredging Construction Company Fabricator: Samsung Heavy Industries
INCREASING SPEED AND REDUCING COSTS
The combination of structural steel and precast concrete slab was selected because it was faster to construct and the structural and foundation cost was 30% lower than competing concrete systems. Several factors contributed to the significant cost savings. The lighter weight of the steel structure was a big advantage on a site with poor soil conditions. Drilled shafts, rather than driven piles, saved an initial $1 million, and a lighter building resulted in $1.25 million in additional foundation savings. The light composite steel-braced frame structure, with 6” thick precast concrete plank and concrete-filled steel box columns in designated areas, saved $1.75 million over a conventional posttensioned concrete structure. The building boasts a semi-finished floor and ceiling created in one operation. This permitted the owner to realize a 5 to 6 month quicker construction schedule. Close interaction between the architects and structural engineers during the design process allowed the structural system to be optimized for cost and weight, and brought the project within the $64 million construction budget. So dramatic were the results of this joint effort that the owner was able to add two floors to the tower without increasing the original steel tonnage. All of these benefits were achieved while satisfying the architectural requirements of a luxury hotel.
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This Steel Composite System Provided Five Key Benefits: • Early Project Completion • Lower Cost than Concrete Systems
17'-8" 14'-3" 204'-0" 13 Spaces @ 13'-6" 14'-3"
• Low Floor-to-Floor Heights • Semi-Finished Floor and Ceiling in One Operation • Higher Ceilings in Guest Rooms Without Increasing Floor-toFloor Heights
PLANKS
25'-0"
DECKING
17'-8"
PLANKS
The tower utilized a composite system composed of steel beams with a 6”-thick precast, prestressed concrete plank in the guest rooms, and metal deck with beams in the corridors. The lateral system was a braced frame with composite box columns filled with concrete.
Far Left: Hilton Hawaiian Village Kalia Tower under Construction. Left: The Completed Hilton Hawaiian Village Kalia Tower in Waikiki, Hawaii.
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The Staggered Truss Structural Steel Framing System
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“Analysis of other framing systems produced strong evidence that the staggered truss system offered a significant number of economic advantages.”
Neil Wexler, P.E., P.C. Wexler and Associates New York, NY
The 6-story, 210-room Mystic Marriott Hotel & Spa overlooks Connecticut’s scenic Groton Reservoir. The hotel was designed to incorporate the scale and imagery of classic New England architecture, and its appearance is reminiscent of the great hotels from the turn of the century. The design team considered several construction systems in the initial phase of the project, including traditional post & beam. However, the Staggered Truss System was selected because it offered, among other distinct advantages, the most flexibility, most reasonable construction costs, and significant design flexibility.
The Staggered Truss Steel Framing System Provided Four Key Benefits: • Fewer Columns Allowed the Creation of More Flexible and Efficient Floor Plans • The lower Number of Columns Reduced Weight and Costs • Faster, All-weather Erection Reduced Time and Saved Money • High Quality Plank Provided a Finished Floor and Ceiling Without the Added Expense of Topping
The Mystic Marriott Hotel & Spa in Groton, Connecticut.
Vierendeel Opening for Corridors
Trusses Span the Entire Building Width
Trusses Are Staggered from Floor-to-Floor
This cross-section depicts the staggered truss framing layout for the Mystic Marriott. The trusses were set at 28’ on center, and designed with 10”-deep, wide-flange chords. The plank is 8” thick and the web members are tubular. Vierendeel panels were incorporated at the corridor and at designated points between rooms. All truss-to-column connections were bolted. The lateral loads are resisted by the staggered trusses as braced frames, allowing the plank floors to act as diaphragms. A rigid connection between the trusses and the plank was achieved with a modified grout that was pumped into plank cores. Nelson studs were welded to the truss chords to transfer the diaphragm forces between trusses.
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INCREASING SPEED AND REDUCING COSTS
The staggered truss system allowed for faster erection than traditional post & beam, reducing the total cost of the superstructure. Though construction took place during the winter months, the majority of the structure was completed expeditiously. Additional savings accrued because the building required fewer columns and less steel tonnage. No transfer girders were required at the second floor over the hotel’s extensive public spaces. This translated into lower costs for the fabrication of the steel, and foundation savings due to the reduced necessity for footings. The truss system used precast plank, which provided a finished ceiling and eliminated the need and expense of gypsum board.
IMPROVING QUALITY AND ENHANCING OCCUPANT SATISFACTION
The staggered truss steel framing system features fewer columns overall, which enabled the design team to create the most flexible and efficient floor plans possible. The public areas within the hotel benefited the most. The 10,000 square foot ballroom, for example, is
completely column-free. This open layout permitted unobstructed site lines for guests, as well as a variety of room configurations that maximized occupancy. The restaurant and spa also benefited from fewer columns by allowing designers to place tables, service areas and treatment rooms in the most efficient manner.
Project: Mystic Marriott Hotel & Spa Location: Groton, CT Owner: Waterford Hotel Group Architect: Brennan Beer Gorman/ Architects, L.L.P. Structural Engineer: Wexler and Associates General Contractor: Wolman Construction
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Advantage Steel: Adding Value to Multi-Story Residential Buildings
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requirements.
AISC MARKETING INDUSTRY SUPPORT
• Specifications • Publications • www.aisc.org
Low cost. Strength. Durability. Design Flexibility. Adaptability. Recyclability. These advantages make structural steel an ideal material choice for hotels, apartments, condominiums and senior residences. Whether the issue is economy, speed or quality, structural steel can meet or exceed the most demanding project
The American Institute of Steel Construction (AISC) is a not-for-profit technical institute and trade association serving the structural steel design and construction community in the U.S. AISC Marketing, a wholly-owned subsidiary supported by the AISC Steel Solutions Center, will help you take a serious look at the structural framing system of your next multi-story residential building. AISC’s Steel Solutions Center and Regional Engineers are available throughout the U.S. to provide preliminary design assistance, comparative cost estimates, and review with you the benefits of using steel to your advantage.
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