2013 pti awards - post-tensioning...
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2013 PTI AWARDSRecognizing Excellence in Post-Tensioning Applications
May 6, 2013 • Hilton Scottsdale Resort & Villas • Scottsdale, AZ
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2013 PTI Awards Program May 6, 2013 • 6:00 p.m. to 9:00 p.m.
Student Scholarships ........................................................................................... 5
TAB Awards .........................................................................................................6-8
PTI Fellows Awards .......................................................................................10-11
Bridges ...........................................................................................................12-17Merit: I-280 Veterans’ Glass City SkywayMerit: I-64 Kanawha River BridgeExcellence: Vidalta Cable-Stayed Bridge
Buildings ........................................................................................................18-23Merit: 2201 Westlake/EnsoMerit: Trump International Hotel and TowerExcellence: San Francisco Public Utilities Commission Headquarters
Parking Structures ........................................................................................24-27Merit: Green Screen Parking StructureExcellence: Joint Traffic Management Center Parking Structure
Industrial/Special Applications ..................................................................28-31Merit: Memorial Wall at Ground ZeroExcellence: Target Field (Minnesota Twins Ballpark)
Repair, Rehabilitation, and Strengthening ...............................................32-37Merit: Reinforcement of the Driscoll BridgeMerit: Rehabilitation of a Parking Garage in Downtown Milwaukee, WIExcellence: Raleigh-Durham International Airport—PG 1 Structural Modifications
Slabs-on-Ground ...........................................................................................38-39Excellence: Emergency Vehicle Operator Course
Project of the Year ........................................................................................40-41Wacker Drive Viaduct Reconstruction
Exhibitors and Sponsors ....................................................................................42
Table of Contents
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2013 PTI Awards Program May 6, 2013 • 6:00 p.m. to 9:00 p.m.
6:00 p.m. Reception7:00 p.m. Welcome – PTI President Marc Khoury
Dinner7:50 p.m. Presentation of Student Scholarships
Presentation of TAB and Fellow AwardsPresentation of Project Awards
• Bridges• Buildings• Industrial/Special Applications• Parking Structures• Repair, Rehabilitation & Strengthening• Slab-on-Ground• Student Projects
8:45 p.m. Project of the Year
Master of CeremoniesKristopher Kriofske
The PTI Project Awards recognize excellence in post-tensioning applications. Any structure constructed or rehabilitated in the last seven years that utilizes PT as a structural component was eligible. Entries were submitted by owners, architects, engineers, contractors, and post-tensioning suppliers.
Awardees were selected by a jury of industry professionals and were judged based on creativity, innovation, ingenuity, cost-effectiveness, functionality, constructability, and aesthetics.
Schedule of Events
Join PTI in honoring and congratulating the following scholarship recipients.
William C. Bailey Memorial Scholarships
Jayson LoveThe University of Utah
Landon TalleyNorth Carolina State
University
Justin Vander WerffIowa State University
Edward K. Rice Scholarships
Mahdi ArezoumandiMissouri S&T
Sean Augustino Cornell University
Andrew IsildarUniversity ofNorth Florida
PTI AMSYSCO Scholarships
Blake GreenThe University of
Alabama at Birmingham
Afsoon NicknamUniversity at Buffalo, The State University
of New York
Student Scholarships
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TAB Awards
Russell Price Award for theMost Active Committee Member
Kenneth B. Bondy is recognized for his outstanding contributions to PTI and the industry as a Member of PTI Committee DC-70 and the Technical Advisory Board
Kenneth B. Bondy is a retired Structural Engineer from Los Angeles, CA. He has specialized in the design and construction of post-tensioned concrete buildings for 50 years.
He is a Charter Ofiicer, Past President, and Director of the Post-Tensioning Institute. He is a member of the PTI Hall of Fame, Legends of Post-Tensioning, the PTI Special Topics Committee, and the Technical Activities Board. He is active
in ACI and received the ACI Joe W. Kelly Award for contributions in education and the ACI Foundation Concrete Research Council Arthur J. Boase Award for advancing design and construction practices in post-tensioned concrete building structures. In May 2013, he was awarded ACI’s highest honor: Honorary Membership. He is also an Honor-ary Member of the Structural Engineers Association of Southern California.
Bondy received his BS in civil engineering and his master’s degree in structural engineering from the University of California at Los Angeles in 1963 and 1964, respectively. He is a licensed civil and structural engineer in California and has been licensed in Hawaii, Nevada, Minnesota, New Mexico, Texas, Colorado, and the Territory of Guam.
TAB Awards
James R. Cagley Medal for theMost Active Technical Committee Chair
Gregory A. Hunsicker is recognized for his outstanding contributions to PTI and the industry as Chair of PTI Committees M-55 and CRT-40
Since joining VSL, Gregory A. Hunsicker has managed projects ranging from the supply and installation of post-tensioning materials to the design of post-tensioned structures. His current role is overseeing manufacturing operations and research and development opportunities within VSL.
Hunsicker has experience with various types of post-tensioned structures, including commercial buildings and
parking structures, circular containment reservoirs, cement silos, cast-in-place span-by-span bridges, segmental bridges (cast-in-place and precast), and stay cable bridges. He has also been involved in structural repair and upgrades and has facilitated several post-tensioning testing procedures.
Hunsicker currently serves on the faculty and is Chair of CRT-40: Bonded PT Field Personnel Committee and the American Segmental Bridge Institute (ASBI) Grouting Course.
He received his MSCE from the University of Massachusetts and is an ASBI Certified Grouting Technician and PTI Certified Bonded Tendon Installer.
He is a licensed professional engineer in Texas.
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TAB Awards
Kenneth B. Bondy Award for the Most Meritorious Technical Paper
Thomas Kang and Yu Huang are recognized for authoring the PTI JOURNAL paper “Nonlinear Finite Element Analyses of Unbonded Post-Tensioned Slab-Column Connections”
Professor Thomas Kang is a Faculty Member at Seoul National University, Korea. He is a licensed professional engineer in California. Before that, he was an Assistant Professor at the University of Oklahoma, Norman, for 4 years and worked as a Consulting Engineer in California for 3 years.
Kang, the lead author, received the ACI Wason Medal for Most Meritorious Paper in 2009 and a PTI Fellow Award in 2012.
He received his BS from Seoul National University, his MS from Michigan State University, and his PhD from UCLA.
Yu Huang is a Structural Engineer at Guard-All Building Solutions in Dallas, TX. He received his PhD from the University of Oklahoma in 2012. His research interests include post-tensioned prestressed concrete design, numerical modeling, and development of finite-element formulation. As an industrial practitioner, he is currently researching and developing engineering tools to make the design process more automated and robust.
Outstanding Service Award
Miroslav is recognized for his outstanding contributions and dedication to PTI and the post-tensioning industry.
Miroslav F. Vejvoda is Technical & Certification Director of the Post-Tensioning Institute (PTI), Farmington Hills, MI. He has been involved in design and construction of all kinds of post-tensioned concrete structures since 1980. For over 21 years, he was with major post-tensioning specialty contractors and for a short period of time was active in his own design consulting company. Between 2000 and 2008, he was a staff engineer at ACI, before joining PTI in early 2009. He serves as Secretary of the PTI Technical Advisory
Board, the PTI Special Topics Committee, and as staff member of most PTI committees. He received his BS in civil engineering (structural) from The School of Engineering at Burgdorf, Bern, Switzerland, in 1980, and his MBA from the Sheffield Business School at the Sheffield Hallam University, Sheffield, UK, in 1997. He is a licensed professional engineer in California, Texas, Georgia, North Carolina, South Carolina, Alabama, and Mississippi, and a European Engineer (EUR ING) in the European Union.
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Guy Cloutier is a second-generation post-tensioning industry veteran. He started his post-tensioning career with Con-force Structures in Calgary over 28 years ago. He is currently the Post-Tensioning Manager for Harris PT, a division of Harris Steel ULC.
Cloutier has been involved in various specialized PT projects, including the Kelowna Floating Bridge (cast-in-place [CIP] bonded and segmental precast), the Richmond Olympic Oval speedskating track for the 2010 Olympics (unbonded), the Seven Mile Dam ( 91-strand ground anchors), and various elevated rapid-transit projects (CIP and precast segmental).
He is a member of the PTI Executive Committee and the Certification Advisory Board and works on various committees that deal with bonded tendons, grouting specifications, and unbonded PT.
PTI Fellow Awards
Carol Hayek is the Chief Technical Officer for CCL Group. She has a wealth of expertise in the design and construction of post-tensioning projects. She is a member of the PTI Technical Ativities Board and various PTI, ACI, and fib committees. She is also a Lecturer at Johns Hopkins University, Baltimore, MD.
Hayek received her MSE and PhD in civil engineering from Johns Hopkins University and her MBA from ESA Business School.
PTI Fellow Awards
Since joining VSL, Gregory A. Hunsicker has managed projects ranging from the supply and installation of post-tensioning materials to the design of post-tensioned structures. His current role is overseeing manufacturing operations and research and development opportunities within VSL.
Hunsicker has experience with various types of post-tensioned structures, including commercial buildings and parking structures, circular containment reservoirs, cement silos, cast-in-place span-by-span bridges, segmental bridges (cast-in-place and precast), and stay cable bridges. He has also been involved in structural repair and upgrades and has facilitated several post-tensioning testing procedures.
Hunsicker currently serves on the faculty and is Chair of the PTI Bonded Tendon Installer Course and the American Segmental Bridge Institute (ASBI) Grouting Course.
He received his MSCE from the University of Massachusetts and is an ASBI Certified Grouting Technician and PTI Certified Bonded Tendon Installer.
He is a licensed professional engineer in Texas.
Edgar Zuniga is an Engineer with over 18 years of experience in both structural engineering and post-tensioning. He is a Senior Engineer in the Technical Services Department of DYWIDAG-Systems International USA, Inc. (DSI) and has been involved in a wide range of projects, including new unbonded and bonded post-tensioning and the repair, rehabilitation, and strengthening of structures such as buildings, bridges, dams, and prestressed concrete pipes.
Zuniga is a licensed structural engineer in Illinois and a licensed professional engineer in 14 other states.
The PTI Fellow award is presented to individuals who have made outstanding contributions to the production or use of post-tensioning and who have made significant contributions to PTI Committees. A minimum of 5 years active PTI membership is required to receive this award.
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I-280 Veterans’ Glass City SkywayLocation: Toledo, OH
Submitted by: Figg Bridge Engineers, Inc. (FIGG)
Owner: Ohio Department of Transportation, District 2
Architect(s): N/A
Engineer(s): Figg Bridge Engineers, Inc. (FIGG)
Contractor: Fru-Con Construction Corporation
PT Supplier: DYWIDAG-Systems International USA, Inc.
Other Contributors:
Numerous other design consultants, construction subcontractors, and material suppliers
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Project Overview:
The I-280 Veterans’ Glass City Skyway over the Maumee River in Toledo, OH, opened to traffic on June 24, 2007, and incorporates unique structural and aesthetic features. The 1525 ft long cable-stayed main span unit features a 440 ft tall single pylon, with the upper 196 ft faced in glass to reflect Toledo’s heritage as a leader in the glass manufacturing industry. LED fixtures behind the glass provide nightly dynamic displays. The project encompasses 2.75 miles of ramps, roadway, and cable-stayed bridge for a total of 1.2 million ft2 of concrete segmental bridge deck.
Previously, interstate and local traffic used the Craig Memorial Bridge, a bascule span that averaged 500 annual openings, stalling traffic. Port of Toledo traffic now uses the new bridge, improving safety, reducing congestion, and extending the Craig Memorial Bridge service life.
The bridge accommodates three lanes of traffic in each direction, along with wide shoulders and ramp and gore areas that meet or exceed current standards for merging, accelerating, and decelerating traffic. Average daily traffic count is 68,750, which will increase over the 100+ year service life.
The I-280 Veterans’ Glass City Skyway is the first cable-stayed bridge in the world to use the innovative cradle system that carries the stays through the pylon. The cable stays use epoxy-coated post-tensioning strands as the primary tensile elements that run from an anchorage at the bridge deck through the pylon and back to the bridge deck, transferring naturally compressive forces to the pylon through the cradle embedded in the pylon.
Jury Comments:
• Incorporates innovative structural and aesthetic features, including a unique pylon design and stay cradle technology that was ground-breaking at the time.
• The single plane stays in combination with the cradle system and precast delta frames post-tensioned into place allowed for larger stay spacing and reduced the number of stays to provide more open-ness at the deck level and more pleasing aesthetics.
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I-64 Kanawha River BridgeLocation: Kanawha County, WV
Submitted by: T.Y. Lin International
Owner: West Virginia Department of Transportation, Division of Highways
Architect(s): N/A
Engineer(s): T.Y. Lin International
Contractor: Brayman Construction Corporation
PT Supplier: VSL
Other Contributors:
Concrete Supplier: Arrow Concrete; Formwork for Cast-in-Place Segments: STRUKTURAS; Bearings: R.J. Watson, Inc.; Expansion Joints: Watson Bowman Acme Corporation; and Prepackaged Grout: BASF
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Project Overview:
The innovative Kanawha River Bridge is a record-setting, low-cost, durable, and aesthetically pleasing post-tensioned box girder structure built as part of the I-64 Widening Project in Kanawha County, WV. The bridge carries I-64 eastbound traffic consisting of three through lanes, one auxiliary lane, and shoulders. The overall bridge length is 2975 ft, including a record 760 ft main span. The superstructure was built using the balanced cantilever construction method with cast-in-place segments supported by form travelers. Bridge construction was completed ahead of schedule, and the structure was opened to traffic for the first time on July 31, 2010.
The bridge designers were confronted with the challenge of designing a 2975 ft long eastbound structure for the new alignment. The requirement to locate the main piers outside the main channel of the Kanawha River dictated a 760 ft main span. The span arrangement studies included five different alternatives for this river crossing: concrete box girder, steel tied arch, steel box girder, concrete cable-stayed, and steel truss. The post-tensioned box girder and steel arch alternatives were selected for the Type, Size, and Location Study. Detailed evaluations of these bridge types considering aesthetics, constructibility, cost, and maintenance requirements resulted in the selection of the post-tensioned concrete box girder alternative for the final design.
The owner later decided to use competitive bidding of the already-designed concrete bridge alternative versus a new steel bridge alternative. Contract plans for a steel bridge alternative consisting of a steel box girder super-structure with the same span arrangement as the concrete alternative were developed. The low bid was the post-tensioned concrete box girder alternative. The bid price for the post-tensioned concrete alternative was $82.9 million, $30 million less than a competing steel alternative. Considering bridge items only, the bid price of the post-tensioned concrete bridge was $75 million. This represents an average cost of $379 per ft2, a very competitive cost considering the long bridge spans.
The Kanawha River Bridge has resulted in significant benefits to the Charleston area. During construction, the extensive use of local materials and labor boosted the local economy. Environmental and public impact were minimized by the use of post-tensioning and cast-in-place long-span balanced cantilever construction. The use of post-tensioned concrete and the expected long design life bring significant sustainability benefits. With the completion of the project, traffic congestion and the pollution associated with congestion have been minimized. The new improved alignment has also enhanced traffic safety.
Jury Comments:
• Project demonstrates the cost effectiveness of post-tensioned segmental box girder construction.
• An aesthetically pleasing structure that fits in well with the local surroundings despite its size.
• The use of PT provided flexibility in both design and construction to accommodate for main span deformations, making the geometrically complicated “S-curve” alignment possible.
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Vidalta BridgeLocation: Mexico City, Mexico
Submitted by: MEXPRESA
Owner: Grupo Altiva, Mexico City
Architect: N/A
Engineer(s): MEXPRESA—Carlos Fernandez Casado
Contractor(s): MEXPRESA
PT Supplier: MEXPRESA
Other Contributors:
High-Performance Concrete: Cemex, and Epoxy-Coated Strand: Insteel Wire
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Project Overview:
Vidalta Bridge is a concrete-steel composite structure that was conceived to maximize the use of post-tensioning techniques. Its 161 m steel main span is supported by means of parallel strand cable stays, while its 78 m compensation back assembly is made of 50 MPa concrete, post-tensioned with multi-strand cables.
The inclined, two-column 50 MPa concrete tower was supported by means of temporary parallel strand cable stays during construction. It features a post-tensioned horizontal brace and has its tension-solicited sections com-pressed by means of PT bars. Finally, the seismic overturn safety is accom-plished through double corrosion-protection ground anchors composed of parallel strands and a post-tensioned two-column tension bent.
The construction process featured the use of six pairs of temporary stays made of four to 12 parallel 0.6 in. strands; and permanent stays to control the cantilever. Force adjustments were required for the different stages.
Architecturally, Vidalta Bridge is conceived as an entrance gate to a private, exclusive housing development in the Lomas district in southwestern Mexico City.
Jury Comments:
• Visually striking structure that maximized the use of PT in multiple structural elements.
• Resulted in a very efficient use of materials.
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2201 Westlake/EnsoLocation: Seattle, WA
Submitted by: Cary Kopczynski & Co.
Owner: Vulcan Real Estate
Architect(s): Callison Architecture
Engineer(s): Cary Kopczynski & Co.
Contractor: Sellen Construction
PT Supplier: PTC
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Project Overview:
For the first time in one building, 2201 Westlake/Enso combines high- strength 100 ksi reinforcing steel with an ultra-long span floor system using a drophead design at the core. The building marries high-end condominiums with long-span office space, spacious ground-level retail, and user-friendly subterranean parking. It is a true mixed-use building—the structure is the result of innovative solutions applied to a complex design program.
2201 Westlake/Enso is a cast-in-place concrete structure featuring concrete shear walls and a combination of one- and two-way post-tensioned slabs. The structural frame was selected to satisfy the architectural layout without compromising the owner’s vision for open and spacious floor plans for office, retail, residential, and parking use. In addition, the combination of structural systems kept construction costs in line with the project budget and delivery objectives.
The building incorporated many exceptional structural features as follows:
• Long post-tensioned spans throughout;
• Cantilever beam to lengthen post-tensioned slab spans;
• Subterranean post-tensioned slab shrinkage control;
• Open loading dock with post-tensioned girders;
• High-strength reinforcing bars;
• Seismic core efficiency; and
• Outstanding exterior façade.
Jury Comments:
• Creative structural solution where the use of post-tensioning directly led to the success of this mixed-use project.
• Design accommodated four different uses (parking, retail, office, and residential) stacked vertically in the building without column offsets and transfers.
• Used an innovative combination of PT and high-strength concrete and reinforcement.
• The long-span PT design facilitated the minimal use of interior columns and construction of the curved exterior façade.
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Trump International Hotel & TowerLocation: Honolulu, HI
Submitted by: Baldridge & Associates Structural Engineering, Inc.
Owner: Irongate AZREP BW LLC
Architect(s): Benjamin Woo Architects LLC and Guerin Glass Architects
Engineer(s): Baldridge & Associates Structural Engineering, Inc.
Contractor: Kobayashi Kiewit Joint Venture
PT Supplier: Supplier: RPS Cable Inc. and Installer: Associated Steel Workers
Other Contributors: Wind Tunnel Study: RWDI
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Project Overview:
Waikiki. Trump. The former is one of the world’s premier vacation destinations and the latter is synonymous with luxury development. The union of these two is the Trump International Hotel & Tower at Waikiki Beach Walk, a 38-story luxury hotel and condominium complex. This highly desirable address set a world record for sales, selling all 464 units in 8 hours for a total of over $700 million.
The location posed a challenge, however. With severe site constraints, building height and envelope restrictions, and a desire to maximize views and sellable space, structural simplicity was not a priority. Baldridge & Associates Structural Engineering rose to the occasion using post-tensioning throughout the project to create innovative solutions to the structural challenges. The resulting building includes optimized thin post-tensioned slabs; 23 transfer girders; a 10 in. thick post-tensioned transfer slab at the penthouse; sloping columns; numerous wall-to-column transitions; unique composite steel plate link beams; and, most critically to the occupants, uninterrupted views of the Pacific Ocean.
One unexpected benefit of the height restriction is the structural efficiency created by the use of a thin post-tensioned floor system. Overall structural weight was reduced by as much as 30%, reducing column, wall, and foundation requirements. As seismic load is proportional to the structure’s weight, the lateral load requirements were reduced as well. While not intended to achieve LEED points, this structural approach qualifies under innovations in design. Even with all of the vertical load transitions, this structure required less concrete and reinforcing steel per square foot than other recently constructed tall building in Honolulu, making it a more sustainable form of construction.
Jury Comments:
• A challenging mixed-use design that had 19 structurally unique floors that effectively used post-tensioning to optimize functional space and maximize value for owners and occupants.
• The result: an architecturally striking structure that features efficient use of materials and high seismic and wind resilience.
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San Francisco Public Utilities Commission HeadquartersLocation: San Francisco, CA
Submitted by: Tipping Mar, Structural Engineering
Owner: San Francisco Public Utilities Commission
Architect(s): KMD Architects/Stevens Associates Architect
Engineer(s): Seismic Engineer: Tipping Mar, Structural Engineering, and Engineer-of-Record: SOHA Engineers
Contractor: Webcor Builders Inc.
PT Supplier: AVAR Construction Systems, Inc.
Other Contributors:
Mechanical Engineer: ARUP; Architectural Interiors: Tom Eliot Fisch; Concrete Vendor: Central Concrete Supply Company; Sustain-ability Consultants: Simon and Associates Inc.; and Curtain Wall: Benson Industries, LLC
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Project Overview:
The LEED Platinum-designed San Francisco Public Utilities Commission (SFPUC) headquarters at 525 Golden Gate Avenue opened in June 2012 after a long saga of budget crises, value engineering, design, and redesign. Called a “sustainability showcase” by Engineering News Record, SFPUC is the product of a host of sustainable-design strategies such as a living machine, which reclaims gray, black, and stormwater; wind turbines; solar arrays; low-cement concrete; and much more. It stands today as a model for water conservation, energy performance, and indoor air quality. Moreover, the novel, vertically post-tensioned concrete structure gives the SFPUC building superior resilience and the ability to self-center after a large earthquake, with only minimal damage resulting, and makes immediate reoccupation possible.
At the project’s genesis, SFPUC mandated that the new headquarters be designed to essential-use-facility standards: in the event of a large earth-quake, it should be easily repaired and immediately reoccupiable. This dictated a standard of seismic performance that would limit structural deformations during a major shock and allow the building to return to its original position, thereby protecting all the building’s systems.
The original SFPUC plan called for base isolation to fulfill the performance requirement on the 12-story building; however, owing to budget constraints, that plan had to be shelved in favor of a system of steel moment frames with viscous dampers. However, the costs were still too high—approximately $62 million more than the $133 million budget.
To cost-effectively meet the performance mandate, the engineers proceeded to redesign the structure using a vertically post-tensioned concrete shear-wall system with composite link-beams. The resulting solution met three important challenges:
• Immediate reoccupancy performance;
• A negligible cost over conventional design; and
• Use of floor-and-column grid set during design development.
In short, the PT shear-wall system redesign allowed the oft-stalled 8-year-old project to finally proceed to completion.
Jury Comments:
• The innovative post-tensioned design replaced two structural steel alternates.
• The PT redesign resulted in a significant cost savings—over $30 million on the $200 million project.
• An innovative use of post-tensioned concrete core shear walls is featured.
• A “sustainability showcase” that exemplifies post-tensioning’s capabilities to save material, improve seismic resilience, enhance functionality, and speed construction.
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Green Screen Parking StructureLocation: Columbus, IN
Submitted by: American Structurepoint, Inc.
Owner: Corporation Name Withheld by Request, Columbus, IN
Architect(s): American Structurepoint, Inc. and Kevin Roche John Dinkeloo Architects (KRJDA)
Engineer(s): American Structurepoint, Inc.
Contractor: F.A. Wilhelm Construction Co., Inc.
PT Supplier: AMSYSCO, Inc.
Other Contributors: GSky Plant Systems, Inc.
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Project Overview:
When a major corporate headquarters announced it would be expanding its offices and adding a new parking structure in downtown Columbus, IN, the city had concerns about the impact on the downtown aesthetics of the large impending footprint. However, with help from American Structurepoint’s architects and engineers, both the corporation and the city were able to find a mutual solution. The project team worked with the corporation to design a 291,300 ft2, 954-space parking structure incorporating many sustainable design principles and maintaining the architecture and historical features of the exterior to blend into its surroundings.
The most unique feature of the $10 million parking garage, which opened in September 2012, is the massive installation of vertical green walls comprising 7000 ft2 of Basic Wall™ living, growing vines by GSky Plant Systems, Inc., (gsky.com) along two of the four sides of the five-story parking garage. The ivy that blankets the parking structure helps to create a park-like setting for employees. Self-contained planters support long-term mass vine growth to soften and create north and south façades, filtering out some sunlight while shielding views of cars from the street. The insulated containers feature a heat trace wire system running underneath, which is designed to prevent root damage from cold temperatures, as well as an automatic irrigation system that detects when the growing medium is dry and provides water to each container. The vines will eventually grow in to fill the galvanized 3 x 5 ft frames attached to the front of the container on the north and south sides of the parking garage, adding to the charm of downtown Columbus.
The long spans and moment frames (instead of shear walls) of the post-tensioned concrete frame helped create an open and secure feel to the garage. With the garage’s efficient geometry, streamlined architecture, and repeatability, the cost per space for the structure came in at approxi-mately $10,500, which is significantly lower than the national average (approximately $16,300/space). The structure opened in September 2012 after only 9 months of construction. The structure is now part of the evolving character of downtown Columbus.
Jury Comments:
• Structure is a good architectural expression that was achieved at a very economical cost.
• Constructed very quickly, with the overall design-build project completed in 300 days.
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Joint Traffic Management Center Parking StructureLocation: Honolulu, HI
Submitted by: Baldridge & Associates Structural Engineering, Inc.
Owner: City & County of Honolulu, Department of Transportation Services
Architect(s): Anbe, Aruga & Ishizu, Architects, Inc.
Engineer(s): Baldridge & Associates Structural Engineering, Inc.
Contractor: Hawaiian Dredging Construction Company, Inc.
PT Supplier: CMC Cable (Supplier)
Other Contributors: Associated Steel Workers (PT Installer)
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Project Overview:
In March 2010, the city and county of Honolulu released a competitive design-build request for proposal (RFP) to design and construct a multi-storied, access-controlled parking structure sufficient to accommodate a minimum of 380 cars in addition to providing parking space for 16 buses and two travel lanes at grade. The RFP included structural documentation for a 128 ft wide by 249 ft long trapezoidal-shaped parking structure but allowed the contractors to submit an Alternate Technical concept.
The RFP included two structural scenarios. The first was a precast prestressed structure using double tees, inverted L-beam girders, and precast perimeter girders. The second was a cast-in-place system using 37 in. deep post-tensioned beams spaced at 18 ft on center.
The contractor, architect, and structural engineer worked together collaboratively to develop an alternate post-tensioned concrete scheme based on a revised column grid optimized for the site dimensions, parking layout, and reuse of the forming system. The final grid system was based on a 24 by 60 ft module that fit equally in to eight bays of the ramping portion of the garage. The layout resulted in a more efficient but slightly smaller 122 ft wide by 247 ft long trapezoidal typical floor that reduced the mass of the building while saving material use for the construction of the parking deck.
The revised column grid also reduced the maximum span of the typical girders without losing any functionality in the garage. This shorter span also allowed the structural depth of the system to be reduced. Through coordination within the team using a project building information modeling (BIM) model, we were able to reduce the floor-to-floor height by 6 in. The final layout included a 6 in. thick post-tensioned slab supported by 31 in. deep post-tensioned girders.
The Joint Traffic Management Center Parking Structure was completed in January 2012. Through the use of post-tensioning, along with the hard work and innovation of the architect, the structural engineer, and the contractor, the city and county of Honolulu now has a parking structure that meets its functional requirements, is an attractive addition to the Hawaii Capital Special District, and is LEED Gold certified.
Jury Comments:• Exemplifies the cost-effectiveness of PT, with the cast-in-place post-
tensioned design being selected over a precast, prestressed alternate.
• Using BIM, the design/construction team was able to reduce the structure size and, as a result, seismic loading, yet maximize the parking stall count.
• Use of cast-in-place post-tensioned concrete enabled the designers to round off two corners to meet the aesthetic requirements of the owner.
• Efficient design resulted in a savings of materials while increasing the number of vehicles that could be accommodated, enabling the structure to attain a LEED Gold rating.
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Memorial Wall at Ground ZeroLocation: New York, NY
Submitted by: DYWIDAG-Systems International USA, Inc.
Owner: World Trade Center Memorial Foundation, USA
Architect(s): Handel Architects, LLP, and Davis Brody Bond, LLP
Engineer(s): Mueser Rutledge Consulting Engineers
Contractor: E.E. Cruz/ Nicholson Construction Company, JV
PT Supplier: DYWIDAG-Systems International USA, Inc. Indu
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Project Overview:
Ten years after the terrorist attack on September 11, 2001, that caused the collapse of the Twin Towers in New York, work at Ground Zero is still in full swing. Apart from several office towers, a museum is being built underneath the foundations of the destroyed skyscrapers to commemorate the attack.
The area’s signature building is an office tower that has been renamed from Freedom Tower to One World Trade Center. With a height of 1776 ft (541.32 m), which stands for the year of the Declaration of Independence, the tower will be the highest skyscraper in Manhattan after its completion.
The post-tensioning subcontractor supplied strand anchors for stabilizing the excavations shortly after the attack. The subcontractor also supplied threadbar tendons and reinforcement systems for the construction of One World Trade Center.
The FDNY Memorial Wall, located opposite Ground Zero, has already been completed and was dedicated by the American president on September 11, 2011. The wall is dedicated to the 343 firefighters of the Fire Department of New York who lost their lives during the rescue work.
For stabilizing and tying back the FDNY Memorial Wall, DSI USA supplied 183 epoxy-coated, double corrosion protected (DCP) 66 mm diameter threadbar anchors 15.5 to 34.4 m (51 to 113 ft) in length with a total weight of 177 tons, as well as 183 anchorages.
Jury Comments:
• A good example of the use of post-tensioned ground anchors to stabilize a building excavation to enable a culturally significant structure to be built.
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Target FieldLocation: Minneapolis, MN
Submitted by: AMSYSCO, Inc.
Owner: Minnesota Ballpark Authority
Architect(s): Populous and HGA
Engineer(s): Walter P Moore
Contractor: Mortenson Construction
PT Supplier: AMSYSCO, Inc. Indu
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App
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Project Overview:
Target Field was unique because of the multiple applications of post-tension construction on the same project. Typically, a single project applies the cables in the same manner, and the construction team is able to gain efficiencies from the repetition. Target Field required much closer coordination between the design and construction teams to ensure a high level of quality control for each different application. In fact, because of the complexity of the design caused by the site constraints, the Construction Manager used building information modeling (BIM) technology to model the post-tension cables and standard reinforcing—a level of detail that is not often required.
One of the greatest benefits of post-tension construction at Target Field was along the third base line over the railroad corridor. The post-tension design reduced the amount of concrete volume, eliminated the need for reshoring through the rail corridor, and enabled the Construction Manager to coordinate a complicated sequence of construction. In one specific 100 x 100 ft area in the northwest quadrant of the project, the design necessitated standard pan-and-joist, cantilevered PT girders, precast double tees, precast plank, and conventional PT girders—almost inconstructable without the flexibility of post-tension construction.
Due to the heavy loading in Target Field, the largest concrete girders required 5805 kip of prestressing force to support the main concourse. More than 200 1/2 in. diameter tendons were used for these post-tensioned girders. To avoid cracking caused by reverse tensile stresses, some girders required stage stressing of tendons because the concrete gained strength and the upper levels added more dead load to the structure. Because some girders had 15 times more post-tensioning than a typical beam in a parking structure, the construction team was concerned about potential conflicts between post-tensioning anchors and materials from other trades. Furthermore, the post-tensioned girders were built before the perpendicular joists to speed up the construction schedule. Accordingly, concrete block-outs/sleeves were embedded into the girder to allow the transverse beam post-tensioning and mechanical, electrical, plumbing (MEP) piping to run through the girders.
Before construction started, BIM was used to coordinate structural design drawings with post-tensioning shop drawings. The detailed three-dimensional (3-D) environment illuminated several problem areas that subsequently were solved by revising the installation drawings. The strong collaboration of the construction team was one reason the project was completed 3 months ahead of schedule.
Jury Comments:
• The use of PT facilitated a complex construction schedule and allowed the design/construction team to deal with challenging site conditions.
• Used highly variable cross sections of structural elements to meet challenging geometric requirements.
• Use of PT contributed to the project achieving a LEED Silver rating.
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Reinforcement of Driscoll BridgeLocation: Over Raritan River, Keasbey, NJ
Submitted by: DYWIDAG Systems International USA, Inc.
Owner: New Jersey Highway Authority, NJ
Architect(s): N/A
Engineer(s): URS-Greiner JV and the DSI Engineering Staff
Contractor: Conti Enterprises, South Plainfield, NJ
PT Supplier: DYWIDAG Systems International USA, Inc
Project Overview:
Garden State Parkway Structure #127.2, better known as one of the Driscoll Bridges, spans the Raritan River, carrying the Garden State Parkway in New Jersey. It is one of the major structures on a highway that carries a large portion of the New York and New Jersey southbound traffic in the middle of a busy confluence of other state roads.
This bridge, built in 1952 under the standards of 1941, consists of steel beam tower piers encased in concrete under deep steel beams carrying a concrete deck in two separate structures. Only two longitudinal girders carry the two nearly 70 ft wide decks.
In 2006, the New Jersey Highway Authority (the bridge owner) decided to completely overhaul the bridge to guarantee smooth traffic flow on the Garden State Parkway.
To manage current speeds and traffic loads, an upgrade in floor beam capacity was necessary. The main intent of the floor beam strengthening was to provide additional moment capacity to bring the moment resistance of the transverse floor beams back to the current codes and based on current loads. Multi-strand tendons were installed to ensure the necessary strengthening.
The design includes two custom anchorages that are bolted to the existing structure and a center deviator, which give the post-tensioning strand the eccentricity necessary to create the additional moment capacity.
Reduced working space above water and an exceptionally tight installation schedule were especially challenging during this project. Being easy and quick to install, the post-tensioning system was predestined to fulfill the owner’s guidelines regarding bridge stability and a construction time of merely 1 year per bridge structure. The two structures of the bridge were returned to full traffic by the end of 2009.
Overall, the project presented an opportunity to develop innovative ways to install post-tensioning to strengthen a badly damaged transportation structure without damaging the existing structures and to effectively deal with current code constraints on a very old structure on a very tight schedule. It was also an opportunity to apply state-of-the-art monitoring systems of transportation assets.
Jury Comments:
• The project demonstrates the innovative use of post-tensioning to strengthen a badly damaged steel structure without damaging the existing structures.
• The project also features the use of electromagnetic sensors to monitor the long-term force in the cables.
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Rehabilitation of a Parking Garage in Downtown Milwaukee, WILocation: Milwaukee, WI
Submitted by: Wiss, Janney, Elstner Associates, Inc.
Owner: Northwestern Mutual
Engineer(s): Wiss, Janney, Elstner Associates, Inc.
Contractor: General Contractor: Structurewerks andPT Subcontractor: STRUCTURAL
PT Supplier: VSL
Project Overview:
The structural rehabilitation of this parking garage involved extensive repairs to the slab post-tensioning system. The repair techniques used were tailored to enhance the efficiency of the repairs and durability of the repaired structure. This repair project also used external post-tensioning to strengthen beams where the beam tendons had deteriorated due to corrosion.
This project included the repair and restressing of almost 600 unbonded slab post-tensioning tendons that had failed or exhibited significant corrosion-related damage. Many of the slab tendons were found to require repair at their end anchorages, where extensive corrosion-related deterioration had occurred due to somewhat unique detailing of the slab edge and inappropriate previous repair attempts. Several other unique conditions at other locations in the garage also contributed to the tendon deterioration. As part of the slab tendon repairs, multiple methods of detensioning were used; many sections of new tendons were replaced using threading and extraction techniques; and all repaired sections of tendons were fully encapsulated, including the spliced connections to the remaining existing tendon sections and the central stressing splices.
The beams addressed as part of this project included a set of beams located at an expansion joint. An unusual condition caused by a construction deficiency allowed water to leak through the failed expansion joint seals and enter the sheathings of the beam tendons, resulting in the corrosion and failure of some of these tendons. To restore the strength of these beams, external post-tensioning was installed on the sides of the beams, which required a unique method of anchoring due to the configuration of the structure at the beam ends. In addition, tendon drying and regreasing techniques were used on these beams to help limit additional beam tendon deterioration in the future.
Jury Comments:
• The project is noteworthy because of its complexity, the variety and number of repairs, and the innovative solutions used.
• Multiple innovative repair techniques were used to address extensive distress throughout the structure.
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Raleigh-Durham International Airport—PG-1 Structural ModificationsLocation: RDU Airport, NC
Submitted by: Walker Parking Consultants/Walker Restoration Consultants
Owner: Raleigh Durham Airport Authority
Architect(s): Walker Parking Consultants/Walker Restoration Consultants
Engineer(s): Walker Parking Consultants/Walker Restoration Consultants
Contractor: Archer Western Contractors
PT Supplier: DYWIDAG-Systems International USA, Inc. Repa
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This project involved removing a significant portion of an existing post-tensioned airport parking structure to allow the airport owner to move a roadway closer to the parking structure. This would allow expansion of a terminal building that was landlocked by runway offsets and roadways.
The portion of the structure removed was an 8 ft wide by 555 ft long cantilever. The project involved cutting through all 22 main post-tensioned (PT) beams, each of which had 11 unbonded PT tendons that had to be detensioned safely, repositioned to allow new anchorage, and restressed while keeping as much of the existing parking structure in operation as possible.
With this strategy, the remainder of the parking structure could be saved and continue in service, thus producing the most environmentally responsible solution for the owner. The alternative was to tear down the entire existing parking structure and rebuild a new, somewhat smaller structure—a much more costly, wasteful option.
The initial discussions about the project included some typical misconceptions (myths) about PT structures. Some of the parties had serious doubts about successfully removing a significant portion of a PT structure while leaving the remaining portion intact.
The engineering firm for the project battled this misconception by laying out a methodical plan to determine the most cost-effective yet practical method to use. In addition to all of the technical challenges and the important environmental impact of the project, the overall success of this project is a shining example of how the common myths concerning the impossibility of structurally modifying PT structures are unfounded. This project debunked these myths and will continue to increase the acceptance and use of PT structures in future projects.
Jury Comments:
• Design/construction team used a variety of post-tensioning repair techniques to provide the most environmentally responsible solution to the owner.
• In the process, they had to overcome many misconceptions regarding PT repair, which they did in a methodical and professional manner.
• The overall success of this project is a shining example of how the common myths of the impossibility of structurally modifying PT structures are unfounded.
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Emergency Vehicle Operator CourseLocation: Camp Ripley at Little Falls, MN
Submitted by: AMSYSCO, Inc.
Owner: U.S. Army
Architect(s): URS
Engineer(s): URS
Contractor: Donlar Construction
PT Supplier: AMSYSCO, Inc.
Other Contributors: Pawan Gupta
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b-o
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d
Project Overview:
The Emergency Vehicle Operator Course (EVOC) is a unique post-tensioned concrete slab-on-ground constructed for the Minnesota Depart-ment of Military Affairs at Camp Ripley. EVOC is a 60,000 ft2 “skid pan” that is made slippery so that vehicle drivers can practice controlling skids. EVOC consists of a 12.5 in. thick concrete slab with 20 in. grade beams around the perimeter. The post-tensioned slab used 6000 psi shrinkage-compensating concrete that was laid on top of two layers of 6 mil thick polyethylene sheet and a 14 in. base course. Additionally, it was separated from an asphaltic “transition” slab by a perimeter expansion joint.
Unlike most post-tensioned concrete slabs of similar square footage, EVOC had two pours of 30,000 ft2 pours each, which were poured on consecutive days. Initial stressing was done at 0.4Fpu (or 16.5 kip) when the concrete in Pour #2 reached 1500 psi. Final stressing was done at 0.8Fpu (or 33 kip) when the concrete reached 3000 psi in both pours. Each 0.5 in. diameter 270 ksi tendon was stressed from both ends to increase the final average force in the tendon. In total, EVOC has 190 bundles of two unbonded tendons spaced at 1 to 7 in. on center in the short 200 ft direction and 150 bundles of two unbonded tendons spaced at 16 in. on center in the long 300 ft direction.
Because the concrete slab would be exposed to aggressive environments from inclement Minnesota weather and test chemicals, the project documents required an encapsulated post-tensioning system of PTI specifications. This should help increase the durability of the concrete and improve life-cycle costs.
Jury Comments:
• A good example of the use of post-tensioning to improve crack control for an exposed slab, which reduces the penetration of water and other liquid chemicals.
• The use of post-tensioning also eliminated control joints that could curl or crack over time.
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Wacker Drive Viaduct ReconstructionLocation: Chicago, IL
Submitted by: Alfred Benesch & Company
Owner: Chicago Department of Transportation
Architect: N/A
Engineer(s): Alfred Benesch & Company andT.Y. Lin International Group
Contractor(s): James McHugh Construction Co. andF.H. Paschen Construction
PT Supplier(s): DYWIDAG-Systems International USA, Inc. and VSL International Ltd.
Other Contributors:
Transystems Corporation, Parsons Brinkerhoff, Burns & McDonnell, and Omega & Associates
Brid
ge
s
Project Overview:
The Wacker Drive reconstruction project is a remarkable example of massive urban construction. Born out of the need to increase the roadway’s safety features and structural longevity, the project involved the cooperation of countless consultants, contractors, city officials, and impacted stakeholders.
The drive’s reopening in December 2012 marked the first time in which both the lower and upper levels were fully open to the public since 2010. Lower Wacker Drive is now a streamlined throughway for both public and personal transit, incorporating 21st-century signalized intersections and service drives with controlled access points. A fresh streetscape now provides aesthetic improvements for pedestrians on the upper level, as well as safer pedestrian features such as larger refuges between traffic lanes at the intersections.
Post-tensioning was the single most critical element used to accomplish the project’s main objectives, affording exceptional flexibility in the design of every major infrastructure component. The project team was able to accommodate heavy loads, unbalanced spans, and geometric anomalies by adjusting the horizontal layout and vertical drape of the strands, which is not feasible using other systems. In addition, the post-tensioning systems allowed for reuse of existing foundations, increased vertical clearance, and additional park space.
Using a combination of streamlined aesthetics, practical design, and state-of-the-art engineering practices, the new Wacker Drive is a testament to engineering and transportation innovation. It would be hard to find another project that was able to accomplish so much, all of which was facilitated by the use of post-tensioning.
Jury Comments:
• Project exhibited multiple uses of PT to address extremely challenging site conditions.
• Excellent example of a public project that serves millions of people that could not have been done with any other structural system.
• Exceptional in size and scope, this urban reconstruction project utilizes post-tensioning to its fullest, resulting in many notable accomplish-ments in structural engineering.
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