Aspire™—Spring 2008

THE CONCRETE BRIDGE MAGAZINE SPRING 2008 g Protecting Against & Evaluating Fire Damage! www.aspirebridge.or

Des Plaines River Valley Bridge on I-355 Lemont, Illinois

Maroon Creek Bridge Replacement State Highway 82, Aspen, Colorado

Loop 340 Bridges Waco, Texas

Taxiway Sierra Underpass Sky Harbor Airport, Phoenix, Arizona Aspire Spring 08.qxp:Layout 1 2/20/08 4:52 PM Page 1

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© 2008 Bentley Systems, Incorporated. Bentley, the B logo, LEAP Bridge, CONBOX, CONSPAN, CONSPLICE, CONSYS, GEOMATH, and RC-PIER are either registered or unregistered trademarks or service marks of Bentley Systems, Incorporated or one of its direct or indirect wholly-owned subsidiaries. Other brands and product names are trademarks of their respective owners. CONTENTS Social Benefits of Sustainable Concrete Bridges Features CH2M Hill’s Holistic Approach 8 Combining design and construction services helps firm meet owners’ growing needs for speed and constructibility.

Protecting Against Fire 18 8 Concrete can help bridges resist a blaze’s high heat and return quickly to service. Evaluating Fire Damage 24 Photo: CH2M Hill. Photo: A Case Study.

Des Plaines River Valley Bridge on I-355 28 Deep Spliced Girders Save Tollway $8 Million. ASBI’s First 20 Years and the Future 34 Maroon Creek Bridge Replacement 38 Loop 340 Bridges 44 Preassembled Bridge Facilitates Overpass Construction. Taxiway Sierra Underpass 48 Aircraft Bridges Take Off.

Departments Editorial 2 Reader Response 4 Concrete Calendar 6 28 Perspective—Sustainability, Social Benefits of Photo: Illinois State Toll Highway Authority. Highway Toll State Illinois Photo: Concrete Bridges—How Green is Our Valley? 16 38 Aesthetics Commentary 42 Concrete Connections 52 Safety and Serviceability 53 FHWA 54 STATE—Concrete Bridges in Arizona 58 COUNTY—Boone County, Iowa 62 AASHTO LRFD Specifications 64 Photo: Parsons. Photo: 44 48 Photo: TxDOT. Photo: Bridge Benicia-Martinez CH2M Hill. Photo: Photo: HDR Inc.

ASPIRE, Spring 2008 | 1 EDITORIAL Executive Editor: John S. Dick Managing Technical Editor: Dr. Henry G. Bridge Sustainability, Part Two: Russell Societal Issues Managing Editor: Craig A. Shutt Editorial Staff: Daniel C. Brown, Roy Diez, Wayne A. Endicott Editorial Administration: James O. Ahtes Inc. John S. Dick, Executive Editor Photo: Ted Lacey Photography. Art Director: Mark Leader, Leader Graphic Design Inc. n this issue of ASPIRE,™ we continue our year- could be reopened to traffic while more long-term Layout Design: Marcia Bending, Leader Ilong program to define sustainable issues in solutions were sought. A more complete report on their Graphic Design Inc. bridge design and construction. On page 16, Kevin work is available at www.aspirebridge.org/resources/. Eisenbeis, a Principal with Harrington & Cortelyou Additional photos are also available on the website Electronic Production: Chris Bakker, Inc., Kansas City, Missouri, outlines the “societal” following the article. Jim Henson, Leader Graphic Design Inc. aspects of sustainability: life safety, accelerated bridge Further expanding on the sustainability theme, M. Ad Sales: Jim Oestmann construction, context sensitive designs, long service life, Myint Lwin, Director of the Office of Bridge Technology Phone: (847) 577-8980 • Cell: (847) 924-5497 and aesthetics. at the Federal Highway Administration, describes the Fax: (847) 577-0129 One life-safety issue impacting bridges is their fire FHWA “green” programs now underway (see page 54). [email protected] resistance. Fire is an ever-present concern of all owner FHWA is actively participating in the Green Highways agencies. As more and more flammable materials are Partnership, a voluntary public/private initiative. Reprint Sales: Mark Leader carried over the highway system, fires will continue to (847) 564-5409 occur with increased frequency. Sustainable Bridge Design Awards e-mail: [email protected] Accordingly, this issue contains two articles on fire Also in the sustainable-bridge area are two award Publisher: that should be of interest to owners and designers alike. programs announced in this issue. The Precast/ Precast/Prestressed Concrete Institute, In the first, on page 18, we report on eight concrete Prestressed Concrete Institute (PCI) is soliciting entries James G. Toscas, President bridge fire events that occurred in recent years. The for its Bridge Design Awards program (see the notice bridges covered illustrate that even after exposure to fires on page 43). One category available to designers is the Editorial Advisory Board: of various intensities, concrete can remain in service, Sustainability Award. The purpose is to recognize the David N. Bilow, Portland Cement Association circumventing long-term closures or long-distance construction of responsible, innovative designs that are (PCA) detours. The primary beneficiary of this concrete-bridge sensitive to the environment while meeting the needs John S. Dick, Precast/Prestressed Concrete capability is the traveling public, who can continue of the public and the owner. Deadline for entries is Institute (PCI) to use these important arteries while owners consider May 23, 2008. Details are available on the PCI website Clifford L. Freyermuth, American Segmental alternatives for repair or replacement. (www.pci.org, select “News and Events”). Bridge Institute (ASBI) That raises a frequent question addressed by Also, the Portland Cement Association (PCA) has Theodore L. Neff, Post-Tensioning Institute (PTI) our second fire-resistance article, on page 24: How created the Sustainable Leadership Awards. PCA Dr. Henry G. Russell, Managing Technical Editor can fire-damaged concrete be evaluated? From the developed these awards to honor public officials who Pacific Northwest, the Washington State Department utilize concrete and other cement-based products POSTMASTER: Send address changes of Transportation (WSDOT) provides details of their in public works projects such as highways, streets, to Aspire, 209 W. Jackson Blvd., Suite 500, investigation into a 3000 °F bridge inferno. Richard bridges, dams, pipe, or water systems that are energy Chicago, IL 60606-9887. Standard postage paid Stoddard, Bridge Design Engineer with the Bridges efficient and beneficial to the community. Be sure at Chicago, IL, and additional mailing offices. and Structures Office of WSDOT, offers important to notify your colleagues about this opportunity for Aspire (Vol. 2, No. 2), ISSN 1935-2093 is information about what they did when tragedy struck. agency recognition. Deadline for entries is May 30, Without precedent, they quickly established definitive 2008. Details are available at www.cement.org/ published quarterly by the Precast/Prestressed analytical methods and determined that the bridge sustainableleadership/. Concrete Institute, 209 W. Jackson Blvd., Suite 500, Chicago, IL 60606-6938. Copyright 2008, Precast/Prestressed Concrete Log on NOW at www.aspirebridge.org Institute. If you have a project to be considered for Aspire, and take the ASPIRE Reader Survey. send information to Aspire, 209 W. Jackson Blvd., Suite 500, Chicago, IL 60606-9887 phone: (312) 786-0300 www.aspirebridge.org Precast/Prestressed American1 Segmental Portland Cement Post-Tensioning Concrete Institute Bridge Institute Association Institute e-mail: [email protected] Cover: Puyallup River Bridge (main photo) Wash. See “Protecting Against & Evaluating Fire Damage” articles beginning on American Coal Ash Expanded Shale Clay National Ready Mixed Silica Fume Wire Reinforcement Association and Slate Institute Concrete Association Association Institute page 18 for additional credits.

2 | ASPIRE, Spring 2008 Long Span Bridge Landmar k

Rendering

Twin wall piers are cast with an inlaid stone pattern. The curved rectangular piers reflect the curved The completed superstructure box girder pier table shape of the superstructure. is revealed with removal of formwork (02.18.08).

Pennsylvania Turnpike Commission continues If you share our passion for their capital plan with the replacement of the creating bridge landmarks, join the I-76 bridge at Oakmont, Pennsylvania, across the FIGG Team. For an exciting career Allegheny River. Pennsylvania's first cast-in-place as a Bridge Design Engineer, CADD concrete segmental bridge was designed by FIGG Designer, Construction Site and is being built by Walsh Group. Twin 2,350' long Engineer or Inspector, please structures are being constructed from above to contact us at 1.800.358.FIGG (3444) preserve and maintain vehicular, river and rail or www.figgbridge.com. traffic below. Spans of 285’/380’/380’/444’/532’/329’ cross the river and Fourteen Mile Island. The bridge is on schedule to open in 2010. AN EQUAL OPPORTUNITY EMPLOYER READER RESPONSE The number of deficient bridges in most First of all, I wanted to congratulate you THE CONCRETE BRIDGEstates MAGAZINE. . . makes the focus of ASPIRE™ mag- on the quality of ASPIRE magazine. I thought WINTER 2008 Torrey Pines Road Bridge San Diego, California azine very timely. ASPIRE gives us a good tool the first issue was great and it just seems to www.aspirebridge.org to learn from each other: about what works, get better with every issue! The latest issue of what looks good, and what can get the job Aspire has PB as its company highlight. I’m

ERNEST F. LYONS BRIDGE REPLACEMENT Stuart, Florida ST. ANTHONY FALLS (I-35W) BRIDGE done with the least impact on the traveling especially interested in this issue because I’ve Minneapolis, Minnesota

FIFTH STREET PEDESTRIAN PLAZA BRIDGE Atlanta, Georgia

DEVIL’S SLIDE B Pacifica, California RI D G E public. Please keep it going! recently relocated to PB’s Honolulu office DAGGETT ROAD BRIDGE Stockton, California Hank Bonstedt and the cover shot is of Keehi Interchange just Dr. Ahlborn’s Executive Director down the street from us. Perspective on Sustainability Central Atlantic Bridge Associates Taka Kimura correctly champions the role of education in the Allentown, Pa. Principal Engineer, PB realization of a sustainable future. Innovative Honolulu, Hawaii solutions are definitely needed; however, none of the three “tenets” of sustain-ability (environmental, social and economic) deserve relegation to a diminutive role. Will merely shifting the focus of engineering education to social and economic tenets rather than environment issues solve our problems? Another question concerns whether an economic cost- benefit analysis accurately reflects environmental values. Social and economic well-being of our species, as we know life, depends on a healthy, sustainable environment . . . Engineering education must not restrict itself to the free-body diagram boundaries within an engineering project. It may not be appropriate to only examine efficiencies of a bridge joint when we need to holistically examine the entire transportation system and its relationship to our other life-support systems. Roger Patocka Estherville, Iowa BRIDGE POST-TENSIONING SYSTEMS: [Editor’s Note: Mr. Patocka raises significant Innovative, Proven and Durable. issues concerning our standard design practice for transportation systems and our focus toward the SYSTEMS Owners and design teams rely on VSL to environment. Individually, we may not have direct control over long-range solutions needed to affect • BONDED MULTISTRAND provide innovative technology and proven ® change for the planet, but we do have choices • VSLAB+ BONDED SLABS systems to maximize the durability of in our design solutions and the materials that • STAY CABLES transportation structures. A world leader in we select on a daily basis that will have positive • VIBRATION DAMPING impacts. This is one of the ultimate challenges of post-tensioning, VSL has evolved into a multi- SERVICES sustainability, changing our design philosophies disciplined bridge partner capable of providing to truly think holistically. See the article on page • SYSTEM INSTALLATION contractors and engineers with design support, 16 that provides another installment in our goal • DESIGN SUPPORT of environmental awareness.] • HEAVY LIFTING as well as construction systems and services • REPAIR & STRENGTHENING for precast segmental, cast-in-place and stay Congratulations on a great inaugural year cable bridges. and your vision that has been realized. This • EQUIPMENT RENTAL is a great magazine that allows the bridge professional to review the state-of the-art of concrete bridges in one publication. One of the few that I put in my briefcase to read whenever I have a moment. Jon Grafton www.vsl.net • 888.489.2687 President, Pomeroy Corporation Perris, Calif.

4 | ASPIRE, Spring 2008 “Future Technology for Concrete Segmental Bridges” NOVEMBER 17-19, 2008 Fairmont Hotel, San Francisco, CA PROGRAM INFORMATION AVAILABLE May 1, 2008

photo courtesy of Kiewit Paciﬁc Company www.asbi-assoc.org/news/symposium/

10953 ASBI Aspire Ad.indd 1 11/6/07 3:21:42 PM

New Benicia- Martinez Bridge Benicia, California Built to withstand earthquakes in a high-seismic zone, the new five-lane, 7,400-ft. Benicia-Martinez Bridge is a lifeline structure for San Francisco Bay Area residents, a challenging designation for a bridge with such long span lengths. To learn more, visit www.tylin.com/ads. Photos courtesy of Caltrans

Two Harrison Street, Suite 500, San Francisco, California 94105 tel: 415.291.3700 | fax: 415.433.0807 | www.tylin.com

ad_aspire_mag_7x4.625in_v04.indd2 2 12/13/2007 11:07:38 PM ASPIRE, Spring 2008 | 5 6

| ASPIRE TECHNICAL EDITOR MANAGING of PurdueUniversity. and iscurrentlyteachingattheCivilEngineeringSchool James M.BarkerwasVice PresidentwithHNTBCorp. CONTRIBUTING AUTHORS Inventory andInspectionStandards. deployment andeducation,theNationalBridge guidance, includingbridgetechnologydevelopment, National HighwayBridgeProgramdirection,policy,and on theapplicationsofhighperformanceconcrete. bridges forover35yearsandhaspublishedmany papers who hasbeeninvolvedwiththeapplicationsofconcrete in Dr. HenryG.Russellisanengineeringconsultant, the MarylandStateHighwayAdministration. reference bookonaestheticsandwasDeputyAdministratorof he hascontinuedtobeactivelyinvolvedintheirdevelopment. Masters, Inc. , Spring 2008 were first written, whentheLRFDSpecificationswerefirstwritten, e, a the authorofBridgescape,a of bridgesandhighways.Heis specializes intheaestheticaspects an e Frederick Gottemoelleris D.C. Heisresponsibleforthe Technology inWashington, of theFHWAOfficeBridge M. MyintLwinisDirector Formerly with Modjeski and Formerly withModjeskiand at theUniversityofDelaware. Professor ofCivilEngineering Dr. DennisR.Mertzis Photo: Ted Lacey Photography. bridges. the designofeightMissouriRiver and railwayprojectsincluding management ofmajorhighway Mo. Hisresponsibilitiesinclude Cortelyou Inc.,KansasCity, Principal withHarrington& Kevin Eisenbeisisa ngineer anda

rchitect, who rchitect, who

November 17-19 November 3-8 November 2-6 October 6-8 August 4-6 July 28-29 July 27-30 June 2-4 May 20-22 May 18-22 May 5-10 May 4-7 May 4-6 April 24-27 April 14-15 Westin Hotel. Chicago, Ill. ASBI International Symposium on Concrete Segmental Bridges Segmental Concrete on Symposium Fairmont Hotel, San Francisco, Calif. Schools International ASBI Certification & Training Personnel Assurance & Embassy SuitesHotelNashville Airport, Nashville, Tenn. Control Quality PCI Renaissance Grand & America’s Center, St. Louis, Mo. Convention Fall ACI Conference Bridge Rosen ShingleCreekResort, Orlando, Fla. National Schools PCI-FHWA Certification & Training Personnel Assurance & Embassy SuitesHotelNashville Airport, Nashville, Tenn. Control Quality PCI Practices Construction Segmental Hilton Sacramento West and Arden on West, Sacramento, Calif. Seminar ASBI Francis MarionHotel, Charleston,Highways S.C. & Bridges on the SouthCarolinaDepartmentof Transportation (SCDOT) andMCEER, UniversityatBuffalo, N.Y. Conference Organized bytheFederal Highway AdministrationSeismic (FHWA), the Transportation ResearchBoard(TRB), National Sixth Exhibition & Conference Pittsburgh ConventionCenter, Pittsburgh, Pa. Bridge International Development Sustainable on Focus Forum: Technology Marriott Denver Tech Center, Denver, Colo. Concrete NRMCA Meating Structures and Bridges on Hilton OmahaandQwestCenter, Omaha, Neb. Subcommittee Schools AASHTO Certification & Training Personnel Assurance & Embassy SuitesHotel-Nashville Airport, Nashville, Tenn. Control Quality PCI Conference Bridge Concrete Hyatt RegencySt. Louis, St. Louis, Mo.2008 NCBC-FHWA Exhibition & Hyatt RegencySt. Louis, St. Louis, Mo. Conference Technical PTI Days Includes meetingofPCIBridgeCommitteeand AASHTO Technical CommitteeonConcreteDesign(T-10) Committee Annual PCI Training J.J. PickleResearchCenter,Certification Universityof Texas at Austin, Austin, Texas Grouting ASBI or telephonenumbersfortheseevents, For linkstowebsites,emailaddresses, CONCRETE CALENDAR2008 go towww.aspirebridge.org.

Taking concrete innovations to new heights

High above the Carquinez Straight, the new Benicia-Martinez Bridge now carries five lanes of northbound traffic, significantly reducing daily traffic congestion for the 100,000 vehicles using I-680. CH2M HILL, in a joint venture with TY Lin International, used lightweight concrete and a cast-in-place method in constructing the 1.6-mile-long bridge.

CH2M HILL applies innovative technology to complete complex projects. We’re a CH2M HILL’s recent leading design-build ﬁrm with more than 60 years of design, construction, and program preservation of the historic management expertise. CH2M HILL can help you take your next concrete infrastructure Rainbow Bridge in Idaho was recognized as the project to new heights. International Concrete Repair Institute’s 2007 Project of the Year.

Solutions Without Boundaries ch2mhill.com/transportation

CH2M Hill’s Holistic Approach by Craig A. Shutt

CH2M Hill’s engineering, construction, and we use frequently, and we consciously Combining design operations capabilities have served a large developed consulting and construction variety of clients throughout the world methods to allow it to happen. More and construction since the firm’s founding in 1946. Those owners are growing comfortable with skills are being integrated closer than ever the design-build format, because they services helps firm today, especially as the company meets recognize that the benefits can help a wider array of needs from owners of achieve their goals. Design-build has been meet owners’ bridges and other transportation structures used with buildings for some time, and throughout the United States. it’s moving into the transportation field growing needs today, because owners are being driven “We are a full-service provider,” explains by pressure on schedules in particular.” for speed and Joe Showers, Chief Bridge Engineer. “We have the depth and breadth of The design-build format can condense constructibility capabilities under one roof to provide the time needed for the project, as flexibility to the client as we participate construction can commence before in a project. These range from the all the design is completed. That not environmental document and planning only saves time but can save money, stages through the final design stage shorten labor schedules, and reduce and include being a designer-constructor. user costs incurred through detours and We span the length of the project from congestion delays. “A cost savings often concept to completion. is produced, but design-build definitely creates a savings in the schedule, which “Design-build is a delivery method that is the critical component in most cases.”

8 | ASPIRE, Spring 2008 ‘More often today, the engineer and contractor work closely together rather than separately.’

The functions used to be fairly split apart, but now owners understand the value of marrying the two closer to aid communication and input.

“We have to look at the total project The Kathleen Road Bridge for savings and constructibility, and over I-4 in Florida was created the emphasis has become the total under a design-build approach project cost, not just savings in design or construction. Our designs definitely and consists of a cast-in-place Some of the 72-in.-deep precast, focus on creating the most cost-effective concrete deck, pretensioned bridge to be constructed, not just prestressed concrete I-girders are concrete beams, cast-in-place designed.” delivered and set for the I-794 concrete piers, prestressed bridges at the east end of the concrete piles, and concrete Traffic Control Key Marquette Interchange project panels for the mechanically in Milwaukee. The project was stabilized embankment walls. Ingredient designed for the Wisconsin Owners also are putting an emphasis The structure replaced a smaller Department of Transportation on traffic control, a result of projects 1958 design. by Milwaukee Transportation becoming more congested as infrastructure expands outward from cities Partners, a joint venture of and becomes more complex. “There are CH2M Hill and HNTB. few green-field sites today,” Showers All photos: CH2M Hill. says. “Many of our projects involve rehabilitation and widening of corridors under traffic, and we have to deal with Designs Are More those challenges. They definitely are Complicated affecting how we plan projects.” Owners are looking for new ideas to aid designs in every way possible, An example of the attention paid to because bridge construction has this factor is the Marquette Interchange become more complicated in the past upgrade in Milwaukee. The $1-billion 20 years, he adds. “Owners are very project encompasses 12 miles of urban cost-conscious today, due to increases freeways, including the design of 50 in costs for materials and labor.” With ramps and construction of more than cost escalations as high as 10 percent 180 bridge structures. It also features per year, it can be difficult to create five levels of roadways and 300,000 budget estimates for bridges that will vehicles per day. The project, a joint be constructed well after the design and venture of CH2M Hill and HNTB, material choices are finalized. features 72-in.-deep precast, prestressed concrete I-girders for the bridges. “Design-build formats in particular bring design engineers and constructors The four-year reconstruction was the together on the same team, working largest and most complex transportation toward a common goal, as opposed to project ever undertaken in Wisconsin, being adversaries,” he says. “More often Showers says. As a result, “Public today, the engineer and contractor work perception of impacts and alternative closely together rather than separately.” routes around the construction were

ASPIRE, Spring 2008 | 9 identified as extremely important the success of the $150-million Colorado to the overall project’s success.” The Springs Metro Interstate Expansion Wisconsin Department of Transportation (COSMIX) project, which reconstructed committed to keeping two lanes open in 16 concrete bridges and widened each direction during construction. another four. CH2M Hill created a joint venture with SEMA Construction to To achieve that, CH2M Hill developed a provide design-build services. detailed schedule to clarify ramp and lane closure times and locations. In addition Those services included weekly meetings to creating disincentives for missing with local business owners, as well as the schedule, the team also introduced maps and signage placed along the a “lane rental” program, which gave routes to ensure changes were well contractors an allotment of hours in which known. More than 20 informal and to close freeway and ramp lanes without formal town-hall meetings were held disincentives. “The lane-rental program during the project’s course, which used was an effective tool to reduce unneeded more than 300,000 cu yd of concrete to lane closures and minimize disruptions to rebuild I-25 through the metro area. the public.” The team also found paths As the largest highway- for temporary roadways to pass under Durability Is Stressed construction project in the existing structures through the core of the Durability also has come to the fore, Colorado Springs’ history, the interchange. as owners look to decrease costs $150-million COSMIX project and create added safety. “Owners Aggressive communication with involved reconstruction of 16 are focusing more on life-cycle costs businesses about detours also has bridges and widening four more. today and understand that it’s worth become commonplace on projects, spending more upfront, because it’s a Rockrimmon Constructors, a Showers says. That was a key element in good investment if you don’t have to CH2M Hill-led joint venture with SEMA Construction, also provided design-build services to expand 12 miles of highway capacity Owners are more willing to spend another and reconfigure two major dollar today to save $10 down the road. interchanges.

10 | ASPIRE, Spring 2008 Working with the Idaho Transportation Department, CH2M Hill strengthened and restored the concrete-arched Rainbow Bridge between Boise and Cascade in Idaho. Key elements included replacing ornate concrete bridge rails, repairing corrosion- damaged stringers, and repairing and replacing corrosion-damaged columns.

spend money on maintenance later on. of highways, and CH2M Hill has been They realize the key is total costs, not at the forefront,” says Showers. The Sharing the Wealth necessarily just initial costs, and they’re goal is to bring clients, stakeholders, CH2M Hill opened its doors in Corvallis, more willing to spend another dollar agencies, and the public together in Oregon, in January 1946 as a partnership today to save $10 down the road.” the earliest phases of projects to among three Oregon State College achieve sustainable solutions sensitive engineering graduates and one of their Current specifications for a 75-year to the project context. This approach professors: Holly Cornell, T. Burke Hayes, life contain “the rules of the road,” he addresses safety, mobility, aesthetics, James Howland, and Fred Merryfield. Some notes, “but some bridge owners are and other community values prior 25 years later, the company merged with asking us to design for service lives of to design being finalized rather than Clair H. Hill & Associates to create CH2M Hill. 100 to 150 years.” European engineers reacting to issues later in the process. already are evaluating ways to create “This need has been driven by the The founders’ concepts were simple but such service lives routinely and are public,” he notes. “People are becoming unusual: Grow the company by solving developing models for it. “We’ll see more sensitive to the infrastructure and clients’ problems, hire creative people to some of that here in the coming years.” the public involvement in designing find new approaches to those challenges, highway and railroad bridges in their and share the benefits of the company’s Likewise, sustainability is gaining communities.” He likens it to the early success with them. The employees own the ground, although Showers notes that 1900s “City Beautiful” movement, when company through a stock-sharing program. it hasn’t become as major a concern in emphasis was put on a city’s physical America for bridges as it is in Europe state and how it could be improved. The company has won a number of awards already. “It’s growing in interest here, That urban-architecture movement for being employee-friendly. For instance, certainly. Energy costs are becoming a found its way into bridge designs, and a it was named one of Fortune magazine’s key aspect of designing bridges, and similar movement seems to be underway “100 Best Companies to Work For” in 2006, the project’s ‘carbon footprint’ is being today. one of “Denver’s Best Places to Work” by discussed more.” the Denver Business Journal, and one of the “Recreating bridges that have become “Top 50 Companies to Work For” by Woman Emphasizing Context local landmarks poses challenges,” Engineer magazine. Sensitivity Showers adds. “To make an exact Along with sustainability is the need for replica of a 100-year-old bridge is tough By the end of the 1960s, the company context-sensitive solutions (CSS), which today, because we don’t build like that had achieved revenues of $6.2 million, CH2M Hill emphasizes in its designs. anymore. If we can create a design generated by 310 employees. The firm The company literally wrote the book that harmonizes with that style, new gained momentum with the 1971 Hill on this concept, as its staff served as technologies and advances in concrete addition and publicity from their partnership primary authors on National Cooperative materials give us far more capabilities on a ground-breaking wastewater treatment Highway Research Program Report for achieving a high-quality, functional, facility. One decade later, the company 480: A Guide to Best Practices for and still complementary design.” had revenues of $95 million and 1800 Achieving Context Sensitive Solutions. employees. “CSS is an emerging trend and An example can be seen in the Rainbow requirement in the planning and design Bridge project, in which a 1933 concrete Ralph Peterson was elected president in 1991, ushering in a period of rapid growth and diversification. By the mid 1990s, CH2M Hill’s 6000 employees produced revenues close to $1 billion. In 2006, the company CH2M Hill has been at the forefront of using reported revenues of $5 billion achieved with 23,000 employees from activities in 31 context-sensitive solutions to meet challenges. countries. ‘Designers are starting to treat concrete as a highly engineered material.’

spandrel-arch bridge over the Payette River between Boise and Cascade, Idaho, was rehabilitated. CH2M Hill provided both design and construction services for the $2.9-million project, which involved reconstruction of corrosion- damaged deck-stringer ends and repair of columns, piers, and arches. Existing decorative bridge rails also were replaced with an identical railing. Throughout the design, the original historic fabric of the bridge was retained whenever possible.

Concrete Helps Meet Challenges Concrete materials can help meet a number of the challenges presented by these trends—and that, too, has been a trend for some time, he states. “The industry has been headed toward more concrete designs for the past 30 or 40 years.” Earlier, virtually every interstate overpass, especially spans of more than 100 ft, was constructed with steel girders. treat concrete as a highly engineered material, and that’s an evolving change. “Everything is changed now. We’re These advances affect what can be seeing precast, prestressed concrete used accomplished with bridge engineering, much more often, with box girder spans and that’s really exciting.” The changes as short as 80 ft. At the same time, have been particularly notable in the some prestressed spliced girders are precast concrete field, with techniques extending to 350-ft-long spans. Spliced- achieved with formliners, coloring, and girders and segmental technology have other aesthetic options. “There really are expanded the use of concrete in bridges, a lot of new options being created.” and post-tensioning is more widespread than ever.” It’s up to designers to stay up to date and incorporate new ideas when The concrete industry has changed applicable, he stresses. “Designers dramatically in recent years, he adds, are gaining awareness, and they’re CH2M Hill supplied design- increasing its capabilities significantly. asking questions about what can be build services for the new In the 1980s and 1990s, many of the accomplished.” For that reason, CH2M I-5/41st Street Interchange advances in bridge engineering could Hill works closely with concrete suppliers be attributed to computer software that (at center) and a new flyover early in the design process. “We don’t allowed designs to be modeled and better want to overspecify materials, so we bridge (far left) that replaced forecasts and calculations to be created. work closely with concrete producers, an outdated left lane exit “But in the last 5 to 10 years, the changes and they’re very constructive with help in Everett, Washington. The we’ve seen have been due to changes in at the concept level. And since we also project included the widening materials and better performance, and are contractors, we can integrate the of about 10 miles of highway that includes concrete.” ideas throughout the process.” and rebuilding bridges and interchanges. High performance concrete is a key The new concepts are expanding example. “Designers are starting to concrete applications in new directions,

12 | ASPIRE, Spring 2008 The new multiple-span Benicia- Martinez Bridge traverses the Carquinez Strait between the City of Benicia in Solano County and the City of Martinez in Contra Costa County, California. The cast-in-place, segmental bridge is built to be a “lifeline structure,” remaining open to emergency traffic after a major earthquake.

he adds. For instance, the firm has lightweight concrete uses normal weight used more often, most usually to aid worked with the Colorado Department sand and lightweight coarse aggregate to contractors in speeding construction of Transportation on one of seven bridges produce concrete that is lower in density rather than for design purposes. the department has developed using a than normal weight concrete. (For more Showers notes. He also has great hopes curved, spliced-girder system. “They’ve on this project, see the Summer 2007 for a variety of new reinforcement pioneered this design and led the way, issue of ASPIRE.™) materials, such as fiber reinforced which is really an interesting approach. plastics or carbon fibers. Owners are definitely sold on concrete “We needed to use concrete that was concepts and are leading its use.” lightweight but that also offered other “A number of states have created properties related to modulus of elasticity demonstration projects with these and creep,” he explains. “We stretched materials, and there is some work being Lightweight Concrete the capabilities in that design, and that is done in Europe,” he says. “I haven’t Evolving happening more often all the time.” seen a massive breakthrough yet, but Concrete mixtures that have led to more there could be one in the next few lightweight concrete also are changing The design for the new 3175-ft-long years. It would be ideal if the material design concepts, he says. “Lightweight concrete crossing of the Fraser River could be put into slabs and wouldn’t concrete is fast becoming a standard, near Vancouver, British Columbia, corrode. An indefinite service life would and it has a tremendous influence on Canada, features a much lower profile be the Holy Grail.” design.” due to the concrete material and a new foundation design, which uses large- As concrete producers work with CH2M An example can be seen in the company’s diameter bored piles to provide cost- Hill toward that goal, the firm will work in a joint venture with T.Y. Lin effective construction in the deep layers continue to improve on its own design International on the Benicia-Martinez of soft silt. The project also features an and construction processes, as well Bridge in California. The project used emphasis on aesthetics, using decorative as their integration, to help cut costs “sand-lightweight” prestressed concrete eagles as a recurring theme on bridge and create designs that meet the more box girders constructed primarily by the towers and other locations. diverse, specialized, and challenging segmental, balanced cantilever, cast-in- needs of all types of bridge clients. place construction method. The sand- Self-consolidating concrete also is being

ASPIRE, Spring 2008 | 13

Post-tensioning is being utilized on bridges in increasingly 2008 PTI Technical Conference varied ways, including cable stays for long-span applications, The 2008 conference will be held May 4-6, 2008, in St. Louis, segmental construction, bridge decks, strengthening, and on Mo., and will feature technical sessions, committee meetings, spliced girders to extend the capabilities of precast elements. and PTI’s 2008 Design Awards. It will be held jointly with the Post-tensioning offers some unique advantages that have lead NCBC’s Concrete Bridge Conference—PTI registrants can to rapid growth in its usage around the world. attend all the bridge sessions. Post-tensioned bridges have performed extremely well, but Design Guides reliability and performance are dependent on quality construc- The updated 5th Edition of PTI’s Stay Cable tion and good design. Education and training is one of PTI’s Recommendations is now available. In addition, PTI’s strategic goals. PTI’s initiatives to assist designers and to help Bridge Committee is working on two design guides: 1) update assure a high quality workforce, include the following: of PT Bridge Manual, and 2) Guide for PT Bridge Decks. Post- tensioned bridge decks offer potential benefits such as reduced Bonded Post-Tensioning Certification cracking and improved durability, lighter superstructures, and This 3-day training workshop is a comprehensive course on all fewer girders. aspects of bonded post-tensioning installation. It is intended for construction personnel, inspectors, and construction manag- For more information, contact PTI or visit our website at ers. Attendees are certified following successful completion of www.post-tensioning.org. the training and subsequent examination. The next course is planned for May 28-30, 2008, in Gainesville, Fla.

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ASPIRE, Spring 2008 | 15 PERSPECTIVE SUSTAINABILITY Social Benefits of Concrete Bridges— How Green is Our Valley? by Kevin R. Eisenbeis

Is sustainability merely a fad or a The excellent fire and seismic resistance concept whose time has come? At every turn, we are exposed to print media, characteristics of these structures further ensures industry dialog, political stumping, and even Hollywood celebrities promoting the public well-being. sustainability and the value of going green. What is this all about, and how does the concrete bridge industry relate? sustainability connotes a much deeper Let’s look at various social benefits of And perhaps of greater significance, why intent. To be truly sustainable, all aspects concrete bridges as they relate to should we care? associated with a structure including sustainability. design, location, materials utilized, This issue of ASPIRE™ focuses on the construction techniques, maintenance, Life Safety social benefits of sustainable concrete impact on the environment, overall Concrete bridges, with their typically bridges. Social benefits, including energy consumption, and effect on redundant structural systems, are safe life-safety issues, accelerated bridge future generations must be considered. bridges. The excellent fire and seismic construction, context-sensitive designs, All elements should be coordinated resistance characteristics of these and aesthetics are just one aspect of the in a manner to benefit society. The structures further ensures the public well- overall theme of sustainable design as it consequences of our decisions now may being. In seismic zones, confinement relates to highway bridges. Future issues affect our children’s future. To put it and corresponding ductile behavior in of ASPIRE will delve into the economic another way, a sustainable bridge design plastic hinge regions provides for minimal and ecologic aspects of sustainable accomplishes our needs now without earthquake damage, low repair costs, and concrete bridges. compromising the ability of future immediate post-earthquake use. With generations to meet their own needs. accelerated bridge construction, rapid In this article, we will examine the social replacement of other bridges that may benefits of sustainable concrete bridges Much of the concern in the field of have been damaged is also beneficial. and how we can balance the impact of going green relates to carbon emissions Concrete bridges also demonstrate our choices on society. in the atmosphere. A reported three- outstanding performance when exposed fold increase in carbon dioxide in the to fire as illustrated by other articles in What is a Sustainable atmosphere since 1977 prompts the this issue. The necessity of safe bridges is Structure? global warming concern. One aspect fundamental to our industry. For a better understanding of the subject, of sustainability is the minimization some definitions are in order. To the or elimination of carbon emissions to Accelerated Bridge reduce the portion of climate change casual observer, a sustainable structure Construction will last a long time and have minimal that may be caused by this phenomenon. Locating bridges where drive times and Precast components allow rapid negative impact on our environment. construction of bridges to occur. With However, to the environmental advocate, travel distances are minimized can reduce overall carbon emissions from vehicles. the advancement of rapid construction techniques, construction time previously measured in weeks and months is now Social Benefits of measured in hours and days. Minimal lead Sustainable Concrete times, locally manufactured products, Bridges and standard shapes make this method Society is the benefactor when our economically feasible. Deck formwork for industry provides safe, long-term, dur- cast-in-place concrete can be eliminated able structures. Even more so when when adjacent precast members are economical, attractive, and low-main- used. Combined with the reduced tenance describes our bridge. Sound disruption to traffic, shorter detour times, Rehabilitation of the Benton Boulevard familiar? Additional benefits occur when and minimal site impact afforded, the Bridge in Kansas City, Mo., allowed construction minimizes site disruption, social benefits are significant. preservation of an existing arch bridge environmental impact, and traffic originally constructed in 1923. congestion, again, all common benefits Context-Sensitive Design Photo: Harrington & Cortelyou Inc. inherent to current bridge construction. A context-sensitive design utilizes a

16 | ASPIRE, Spring 2008 Aesthetic requirements played a key role in selecting the type of bridge for the 27th Street Bridge, Kansas City, Mo. Photo: Harrington & Cortelyou Inc. collaborative approach involving all Recent advancements in the use of while still meeting safety needs. Many key stakeholders when considering the higher strength concretes combined with traffic signals and message signs utilize total setting in which a project will exist. prestressing provide for extremely durable this technology, why not bridge lighting? Concrete structures adapt well to various concrete structures. Where corrosion Lowering the power consumption for physical settings often preserving scenic, of reinforcement is reduced, future the life of the bridge, including energy aesthetic, historic, and environmental maintenance requirements diminish used in fabrication, distribution, resources. The advantage of concrete accordingly. Durable concrete bridges are installation, and maintenance, reduces bridges is apparent in the number of long-term structures, minimizing the cost its “footprint” in the realm of carbon communities improved by their use. of future repairs and life-cycle energy dioxide emissions. Designing with “local” consumption. in mind can cut transportation costs Aesthetics and fossil fuel consumption in shipping Concrete bridges blend well with their Where Do We Go from materials and products. This aspect often surroundings. The simple, clean shapes comes into play now resulting in lower Here? costs for construction, but what about provide attractive spans in individual or We should first answer the question, on a macro level. Should we consider multiple arrangements. Low span-to- why do we care? Regardless of personal the consequence in carbon emissions depth ratios create slender lines and feelings about global warming, for shipping a product a long distance, enhance their graceful appearance. carbon credits, LEED certifications, from overseas for instance, just because or any of a myriad of “green” terms, it had the lowest initial cost? Remember, it is important to realize our decisions Long Service Life our decisions have consequences. A Another key aspect of sustainability have consequences, and our actions reasonable balance between economy is longevity. When maintenance can make a difference. It seems safe to and environmental concern is in order. requirements are minimized, the amount say we all want to preserve or improve of effort and energy required to repair our environment, and we want our As summarized above, concrete bridges the bridge in the future is minimized. children and our grandchildren to have provide many social benefits. From fire- a better environment than we enjoy. As resistant and seismic-resistant structures, practitioners in our industry we can take to rapid construction and attractive, steps that may make a difference. long-term installations, concrete bridges provide sustainable solutions that With a few minor variations in current benefit society. In our quest for continual mindset and practice, we can continue improvement, we should ask ourselves: to improve on our bridge sustainability. Can we do more? Because our decisions Advocates for sustainability promote have consequences, we can decide to designing, building, and maintaining make our children’s valley greener as The Route 100 precast box beam bridge with overall energy consumption in mind. we continue to realize the benefit of provides a shallow structure depth over For example, providing solar powered sustainable concrete bridges. I-44 near St. Louis, Mo. Photo: MoDOT. lighting can reduce power requirements

ASPIRE, Spring 2008 | 17 Protecting Against

by Craig A. Shutt

Concrete can help bridges resist a blaze’s high heat and return quickly to service

On June 20, 2007, a fuel tanker truck under the bridge to the busy state rear-ended a loaded dump truck on State route as soon as pavement repairs were Route 386 under the Stop Thirty Road completed. Traffic returned to service Bridge north of Nashville, Tennessee. The on Stop Thirty Road after core samples tanker erupted into flames beneath the were evaluated. 233-ft-long structure, a two-span, two- cell, hollow box-beam bridge. Fearing “The analysis showed that the bridge damage that would interrupt traffic for endured much heat but sustained very little damage,” says Wayne Seger of ‘The analysis showed that the bridge endured the Office of Bridge Inspection and Repair at the Tennessee Department much heat but sustained very little damage.’ of Transportation. The affected span was 120-ft long. The bottom slabs of many months, both on and below the the hollow box-beams are 7.25-in. bridge, inspectors, and maintenance thick, and the sides of the box crews rushed to the site to conduct sections along with the common wall studies on the concrete once the fire between the cells are 1-ft thick with cooled. After analyzing the bridge and two mats of reinforcement. Class A, finding no problems, traffic was restored 3000 psi concrete and epoxy-coated

18 | ASPIRE, Spring 2008 Photo: U.S. Fish & Wildlife Service

Following a fire on the Bill Williams River Bridge in Arizona, it was determined that the girders could be repaired. Photo: Arizona Department of Transportation.

reinforcement had been used to material offers considerable resistance to construct the bridge in 1981. fires that could otherwise render other bridge types unusable. Concrete can After the bridge cooled, potential spalls were chipped off and concrete The key problem is that bridge fires tend better endure these cores were cut to allow engineers at to be exceptionally hot, as they’re caused CTLGroup in Skokie, Illinois, to perform by an external source of intense heat, relatively short-duration, petrographic analysis. “The evaluation such as fuel from an overturned truck or high-temperature fires. showed that the concrete was in good tankers carrying chemicals, says Richard B. shape, so we removed the restricted Stoddard, Bridge Design Engineer with the load posting signs and returned the Washington Department of Transportation, prescribed in the ASTM fire-resistance bridge to service,” he says. who inspected a fire-damaged bridge in test,” he said in his report. “Additionally, his region (for more on this project, see the the heat-transfer mechanism in Keeping Cool following article). tanker fires is dominated by radiant Engineers are well aware of the strength energy as opposed to hot-air and and durability that concrete can offer for “Tanker fires caused by highway heat convection.” Concrete, with its bridge designs, allowing longer spans fuel-trucks or railway tanker cars are high specific heat, can better endure and long-term life cycles with minimal explosive in nature and greatly exceed these relatively short-duration, high- maintenance requirements. But the the temperatures and rate of heating temperature fires.

ASPIRE, Spring 2008 | 19 The heat from the Puyallup River Bridge fire was intense enough to cause damage to all 15 lines of girders.

Bridges Survive Fires A variety of bridges around the country have suffered spectacular bridge fires yet have been able to return to service quickly due in part to the use of concrete. For instance, on July 28, 2006, a fuel truck crossing the Bill Williams River Bridge on Route 95 in Parker, Arizona, girder section was rated for flexure and crashed about halfway across the shear and compared to a prefire condition. Tucson, Arizona. The firm worked with structure. Built in 1967, the bridge spans It was determined that the fire resulted in CTLGroup to identify the depth of the fire the Bill Williams Wildlife Refuge, which a 6 percent reduction in the bridge load damage in structural elements, determine receives about 70,000 visitors per year. rating for the short term and a 12 percent the extent to which spans were damaged, reduction for the long term. Based on and note any reductions in section The tanker spilled approximately 7600 these results, and following a study of properties and material strengths. gallons of diesel fuel onto and under multiple alternatives, it was determined the bridge, which then ignited and that the girders could be repaired. Both Their assessment found that the burned on the bridge’s AASHTO Type III lanes on the bridge have remained open overhang and shoulder in three spans, precast, prestressed concrete girders and to traffic since the accident. especially the ninth span, needed to composite reinforced concrete deck. The be replaced. “The fuel spilled through fire-damaged girders did not show visible “The damage wasn’t as bad as we initially the deck drains and expansion joints, signs of loss of prestress but experienced feared,” says Martha Davis, Structural spreading the fire under the bridge, varying degrees of spalling. A reduced Engineer for HDR Engineering Inc. in and the wind whipped the fire along

20 | ASPIRE, Spring 2008 Although flame temperatures at this methanol-fueled tanker fire under the Puyallup River Bridge, Wash., reached 3000 °F, the precast concrete bridge was reopened to traffic the next day.

The prestressing steel did return to its full strength without causing any deformation in the bridge girders following the fire. The blackened beams of the Bell Isle the bridge’s barrier and overhang,” was hot enough to melt aluminum and Bridge, Oklahoma City, Okla., Davis explains. But the girders in those leave it puddled on the ground nearby,” were cleaned and the bridge spans, and in all of the others, retained reports Greg Clemmons, Operations was reopened. their structural integrity. Transportation Engineer for the Washington County Land Photo: Oklahoma DOT. officials closed the shoulder on the Use and Transportation Department. affected span to keep vehicles off the overhang and to protect the barrier until An inspection of the bridge showed that repairs could be completed. spalling occurred in an approximate area of 2 sq ft and was 1/2- to 3/4-in. deep. Those repairs are still to be scheduled, she In several areas, the concrete also turned notes. The plan is to save as much of the pink, indicating it had been exposed existing reinforcement as possible and to heat of at least 500 ˚F. Following rebuild the overhang, repair damage to the pressure washing to remove soot, a girders where reinforcement was exposed detailed inspection took place, including and concrete spalled, and add a protective hammer tests at various locations. coating to the deck to inhibit corrosion. The bridge also is being monitored to ensure no Following the inspection, the bridge was signs of additional damage arise. reopened to traffic. “The prestressing steel did return to its full strength An even faster return to service took without causing any deformation in A blazing car fire caused damage to place for a ramp to the Northwest the bridge girders following the fire,” a bridge in Washington County, Ore., Expressway in Oklahoma City, Clemmons reports. Debonding of the but the affects were minimal and the Oklahoma, when a truck crashed on the strand possibly took place at the center bridge was reopened to traffic after of the component, he notes, but central nearby Belle Isle Bridge on January 28, an inspection. 2006. A portion of the truck became debonding would not produce any airborne and crashed to the ground significant concern if the ends remain near the ramp, where the resulting fire intact. “There was localized damage, but it did not impact the bridge’s operation.” blackened the ramp’s AASHTO Type II Some spalling and exposed aggregate prestressed concrete beams. But after were noted during the inspection of the evaluation, the blackened beams were Although the department considered Washington County, Ore., fire, but it was cleaned and the bridge was reopened. cleaning and repairing the spalled areas immediately, the damage was not sufficient to require repairs. “There was superficial damage that determined to be so minor that the we repaired,” explains Walter Peters, bridge instead was put onto the county’s Assistant Bridge Engineer for Operations accelerated inspection list. in the Bridge Division of the Oklahoma Department of Transportation. “It was Fast Replacement is Option mostly smoke damage and minor spalls.” Another approach to maintaining traffic on a precast concrete bridge was used A similar result occurred at a precast by the Connecticut Department of concrete bridge in Washington County, Transportation. A tanker truck carrying Oregon, in November 2004. A derelict 8000 gallons of gasoline jack-knifed car was abandoned in an area beneath during an accident, spilling its contents the bridge and set on fire, causing over and under the 80-ft-long bridge charred concrete on the bridge above and over the Norwalk River near Ridgefield, disruption to traffic. The damage occurred Connecticut. The resulting fire exposed at about midspan on a 37.5-ft-long span the precast concrete bridge to severe using 18-in.-deep voided slabs. “The fire heat and fire damage.

ASPIRE, Spring 2008 | 21 After a tanker truck overturned, caught fire, and burned out on a bridge spanning the Norwalk River near Ridgefield, Conn., engineers decided to resupport the 50-year-old precast concrete bridge with intermediate supports. The bridge reopened to traffic in four days.

on the safe side,” she says. “But the closest detour is 100 miles away.”

Even to do the work that will be needed on the overhang will require closing one lane and operating alternating-direction access during construction. “Work like this totally impacts traffic, especially see the bridge still was in reasonably in an environmentally sensitive area,” good shape,” he says. “We were she says. But that disruption is nothing confident that if we shortened the spans compared to what would be required of the precast concrete beams, enough had the bridge been unusable and users strength remained to support the loads had to drive 100 miles out of their way Gasoline that spilled from the tanker- until a replacement could be built.” until a new bridge was completed. truck accident on the bridge over the Norwalk River caused spalling on the Installing the support beams took two Two major fires on highway structures precast concrete but left it in “reasonably more days, and the bridge reopened in California last year demonstrated the good shape,” engineers reported. to traffic only four days after the fire disruption that they produce. The first occurred. A temporary bridge was in April was caused by a gasoline tanker created adjacent to the bridge, and once truck that crashed and exploded into The 50-year-old bridge, one of the it opened, work on replacing the original flames at the MacArthur Maze—one first precast concrete bridges built in bridge with another precast concrete of California’s heavily traveled freeway the United States, suffered significant version began. That work was completed interchanges in the San Francisco Bay amounts of spalled concrete on its a few months later, producing a brand area. Although the steel superstructure beams, reports Arthur Gruhn, Chief new bridge to replace the fire damaged of one connector collapsed, only 4 ft Engineer. Reinforcement was exposed one in only four months. of concrete at the top of two columns in a number of locations. “We really had supporting one outrigger bent were no idea how strong the bridge still was,” In fact, a later evaluation of the beams replaced. The original steel bent cap was he says. Despite its age, the bridge had performed at the FHWA Turner-Fairbank replaced with a concrete one because it been in good condition, and there had Highway Research Center showed that could be manufactured more quickly. been no plans to replace it. concerns over the short-term structural integrity of the beams were groundless. The second event in California occurred The design team moved into action “The investigation found that the flexural in October when a truck exiting a quickly, setting up a detour and capacity of the beams had not been 550-ft-long truck-bypass tunnel on I-5 providing an initial inspection on the degraded significantly as compared to near Santa Clarita lost control resulting day of the accident. On day two, their anticipated capacity,” wrote Gary in a multi-vehicular collision and massive a contractor and remediation crew L. Henderson, Director of the Office of fire in the tunnel. Although the collision examined the bridge to determine its Infrastructure at the Federal Highway occurred at the exit from the tunnel, the status. The team decided that the bridge Administration in his report dated winds drove the flames so that most fire was still structurally sound but needed February 2007. However, their long- damage occurred at the tunnel entrance. some temporary intermediate support term durability may have been degraded The tunnel structure consisted of concrete to ensure its stability. by the fire, he noted, so replacement box girders supported on top of concrete would have been needed eventually. See strutted abutments. Repairs consisted of Two heavy steel support beams were Concrete Connections on page 52 for the building a new wall in front of portions of added, one under either edge for website address with the full report. the wall that were damaged and replacing the length of the span, and three approximately one-sixth of the total additional, shorter beams were inserted Avoiding such replacements can superstructure with precast girders and a perpendicular to these at the one- ensure budget and time are spent on cast-in-place concrete deck. This solution quarter and one-half points. In addition, projects where they are needed. HDR’s was adopted as the most conservative a Jersey barrier was placed along the Davis knows the balance that must be approach and allowed the tunnel to open damaged bridge railings. obtained. “If there was a close detour 15 days ahead of the deadline. for the Bill Williams River Bridge, and “We really couldn’t gauge how much money was no object, we might do For more information on this or other damage the fire had done, but we could more to improve the bridge, just to be projects, visit www.aspirebridge.org.

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ASPIRE, Spring 2008 | 23 A Case Study Evaluating

by Richard B. Stoddard, Washington State Department of Transportation

In December 2002, a railroad tanker The fire consumed 30,000 gallons Visual Inspection collision caused a fire under a of methanol, engulfed Span 8, and and Mapping prestressed concrete girder bridge maintained a high flame temperature Visual inspection of both columns at crossing the Puyallup River in Tacoma, for approximately 1 hour. The bridge Pier 9 approximately 60 ft from the Washington. The bridge, constructed in was closed immediately pending further source of the fire, showed 2-in.-deep 1997, had span lengths of 146 ft with inspections. The bridge displayed no spalls that exposed spiral reinforcement W74 girders spaced at 5-ft 0-in. centers. unusual deflections or misalignments for the full height of the column. The Specified 28-day concrete strengths and was reopened to commuter traffic concrete inside the spiral sounded were 7000 psi in the girders and 5000 and legal weight trucks on the morning like delaminated concrete. Further psi in the columns and bridge deck. after the fire. investigation revealed delaminations

24 | ASPIRE, Spring 2008 within the concrete just inside the for Fire Resistance of Precast, Prestressed the strands could have lost strength and spiral cage and vertical reinforcement. Concrete, hardness testing was performed that relaxation of the prestress force The crossbeam above the columns on the bottom flanges and webs of the could have occurred. had several areas of spalling but no girders using a Schmidt hammer. The reinforcement was exposed. purpose of the tests was to map relative Prior to removing samples of prestressing changes in concrete hardness along strands for material testing, simple All 15 lines of girders in Span 8 were the length of each girder. The rebound deflection tests were performed to damaged and the corners of the hammer readings for the soffit of the calculate the prestressing force. The tests bottom flanges could easily be removed bottom flanges in Span 8 ranged from 42 were conducted before the strands were to expose the outermost strands. The to 61 compared to 61 in girder concrete cut and after the strand replacement soffit of the concrete deck displayed no not affected by the fire. The minimum splices were tensioned. The strand evidence of spalling. hardness occurred directly over the heat deflections were induced by hanging a source and in general, hardness increased 173 lb weight on the strand. Deflections Visual inspection of the damage in Span with distance away from the heat source. were measured multiple times by two 8 included recording the concrete color inspectors using a dial caliper with a variations on the soffit of the bottom The web hardness readings did not measurement accuracy of 0.001 in. flanges that corresponded to changes follow a pattern of regular change This method was estimated to have a in concrete condition. The color regions because shadowing by the bottom flange probable accuracy of 5 percent and was were described as extreme-white, affected the distribution of web damage. certainly accurate to within 10 percent ash-white, white-gray, and soot. The The bottom flange protected some parts of the actual tensile force. Based on different colors corresponded with of the webs from severe fire damage. this approach, the strands in the hottest different exposures to the fire with the zones appeared to have retained 100 extreme-white region representing the percent of their design force. most intense exposure directly over the Prestressing Strand fire source. The prestressing steel in the girders Three samples of strand were removed and consisted of 1/2-in.-diameter 270 ksi tested for yield strength, tensile strength, strands. Concrete surrounding the and modulus of elasticity. The strand Concrete Hardness straight strands in the bottom flange samples met the requirements for 1/2-in.- Mapping was easy to remove with a light diameter uncoated seven-wire prestressing In accordance with the recommendations rock hammer. Because of the high strands per ASTM A 416-96 indicating that for Post Fire Examination of the PCI Design temperatures, there was concern that no metallurigical changes occured.

The fire engulfed Span 8 and maintained a high flame temperature for approximately 1 hour.

ASPIRE, Spring 2008 | 25 Spalling of concrete cover on the columns The pink color shown in this girder from the Puyallup bridge fire indicates that the resulted in areas of exposed spiral concrete was exposed to temperatures higher than 500 ˚F. reinforcement.

Concrete Core Samples Compression tests performed on core in the column appeared to have very Eight vertical concrete cores from the samples indicated that much of the good strength. hot zone, two vertical cores from the undamaged concrete had a compressive coolest zone, and eight horizontal cores strength exceeding 9000 psi. Significant A core sample from the crossbeam at from the hot zone were removed from portions of core samples from the Pier 9 did not show any abnormalities the prestressed concrete beams. Seven hottest zone, however, were fractured and indicated that the crossbeam cores were examined petrographically and untestable. sustained only superficial damage from in general accordance with ASTM the fire. C 856. The extent and severity of fire Eight concrete cores were taken from damage was based on observed changes the two columns at Pier 9. These Summary in aggregate and cement paste color, confirmed the existence of delaminations The railroad tanker fire subjected all 15 mineralogy, and microstructure. Based on in the interior core of the column. The girders in Span 8 to intense heat in a the petrographers’ evaluation, which also maximum depth of fracture was found short period of time. Flame temperatures included some informal heating tests, to be 5 in. from the original surface were estimated to be approximately the state was convinced that surface and more than 1 in. inside the vertical 3000 °F and surface temperatures on the temperatures on the bottom flange column reinforcement. Aside from the soffit of the prestressed concrete girders soffits exceeded 1500 °F during the fire. delaminations, the concrete remaining may have reached 1700 °F. Internal temperatures in the bottom flange and webs were estimated to range from 500 to 1100 °F. The prestressing steel survived the fire without noticeable loss of prestress.

Rapid identification of concrete damage zones can be made by observing the variation in concrete color immediately following a fire. The visual color mapping correlated very well with variations in concrete hardness. The rebound hammer test validated the visual observations and provided an objective description of the damaged areas. With this information, rational discussions could be made about repair or replacement.

All 15 lines of girders in Span 8 were damaged by the fire but the bridge was opened on the next morning.

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ASPIRE, Spring 2008 | 27 PROJECT Deep Spliced Girders Save Tollway $8 million by Daniel C. Brown

The finished bridge has 18 spans with simple pretensioned concrete beams and 17 spans with post-tensioned spliced girders.

Des Plaines River Valley Bridge on I-355 / Lemont, Illinois profile ENGINEER: Janssen & Spaans Engineering Inc., Indianapolis, Ind. DESIGN QUALITY ENGINEER: Bowman, Barrett & Associates, Chicago, Ill. PRIME CONTRACTOR: Walsh Construction Group, Chicago, Ill. PRECASTER: Prestress Engineering Corp., Prairie Grove, Ill., a PCI-Certified Producer SECONDARY GIRDER PRECASTER: Prestress Services, Decatur, Ind., a PCI-Certified Producer

28 | ASPIRE, Spring 2008 The 1.3-mile-long Des Plaines River Valley Bridge has 34 piers and 35 spans, which range up to 270 ft long. All photos: Illinoise State Toll Highway Authority.

Bridges like this one don’t come along based bid specification that would very often. The 1.3-mile-long Des Plaines allow contractors to propose their own River Valley (DPRV) Bridge on I-355 near design.” the Chicago suburb of Lemont, Illinois, is the state’s first to use post-tensioned, Chicago-based Walsh Construction precast, prestressed concrete spliced joined forces with Janssen & Spaans bulb-tee girders. Its success means that Engineering Inc. of Indianapolis, Indiana, it also won’t be the last. to submit a $125-million, design-build proposal for the post-tensioned, spliced- Opened last November, the DPRV Bridge girder design. The design represented combines the use of post-tensioned the highest-priced bridge in Tollway spliced bulb-tee concrete girders and history—but it still was the low bidder. pretensioned concrete bulb-tee girders. Offering a The post-tensioned spliced girder span The winning proposal and the segmental lengths range from 216 to 270 ft, while concrete box-girder bridge alternate performance the pretensioned concrete girders have were both lower than the $175 million specification span lengths ranging from 114 to 170 ft. bid for a steel plate-girder structure. created Creating a performance specification cut benefits costs, created flexibility, and saved 6 to 8 months. to entire Officials at the Illinois State Toll Highway “Not only did the performance construction Authority (Tollway) had originally specification allow us to mitigate the designed the bridge in two other price fluctuations and save money, it team configurations: a steel plate-girder gave the contractor the flexibility to bridge and a segmental concrete box- build what he was comfortable with, girder structure. “Shortly before the and saved us 6 to 8 months in design,” project was advertised for bids, there says Colin Makin, the Tollway’s Deputy was a lot of fluctuation in material Program Manager for Bridges. prices, especially steel,” says Paul Kovacs, Chief Engineer for the Tollway. Indeed, the Walsh-Janssen team was “To address the fluctuations, the Tollway awarded the contract in December decided to include a performance- 2005, before design was complete. By

Multi-Span Precast, Prestressed Concrete I-Beams and Post-Tensioned Spliced Girders / Illinois State Toll Highway Authority, OWNER POST-TENSIONING CONTRACTOR: Dywidag Systems International (DSI), Bolingbrook, Ill. BRIDGE DESCRIPTION: A 1.3-mile-long bridge with 252 girders 90 in. deep; 300 girders 102 in. deep; 60 girders 120 in. deep BRIDGE CONSTRUCTION COST: $125 million

ASPIRE, Spring 2008 | 29 Each side of the bridge has six beam lines.

Two cranes prepare to place a drop-in segment. A strong-back is located at the right-hand end of the beam being lifted.

the following March, the contractor their pier caps. “Over the piers, there’s had begun drilling foundation caissons. about a 1-ft-wide gap between the ends of Meanwhile, Janssen & Spaans finished the bulb-tee girders,” says Brian Slagle, Vice superstructure design. The DPRV Bridge President at Janssen & Spaans. “Reinforcing spans over two canals, several railroad steel protrudes from the ends of the beams lines, two local roads, the Des Plaines into the gap. And when you cast the deck River, and forest preserve land. and make the closure you lock the beams in at that point, establishing continuity. The spliced girder design minimized There are no joints at the piers.” the impact on the wetlands. A typical simple-span prestressed concrete girder is a 90-in.-deep bulb The bridge has a total of 34 piers tee, with a top flange width of 4 ft 11 and 35 spans. The bridge features 18 in., a web width of 6 in., and a bottom pretensioned concrete spans and 17 flange width of 24 in. The typical post- post-tensioned spans. The tallest pier tensioned bulb-tee girder is 102 in. deep cap is 82 ft above grade, with the bridge with a top flange width of 5 ft 1 in. and deck rising to 90 ft at the highest point. a bottom flange width of 26 in.

The simple spans at the DPRV Bridge are “We haunched the girders on the made continuous with closure pours over 270-ft-long spans,” Slagle explains. “We

30 | ASPIRE, Spring 2008 Formwork for pier columns shown during concrete placement.

The $6.3-billion Plan The DPRV Bridge is the largest of 18 construction contracts let by the Tollway for the I-355 South Extension. The 12.5-mile South Extension connects I-55 on the north end with I-80 on the south. Together, the South Extension and the rest of the I-355 Tollway have been named Veterans Memorial Tollway.

The I-355 South Extension is part of the Tollway’s long-term $6.3-billion congestion-relief plan called Open Roads for a Faster Future. In late 2004, the Tollway’s Board of Directors approved the plan, which is scheduled to last through 2016. One of its programs is Open-Road Tolling, by which 20 mainline toll plazas are made the typical girder 102 in. deep, “The strong-backs supported the beam being converted to barrier-free design. but it’s haunched to 120 in. over the in place, after which we could release In addition, most of the tollway piers, where you get maximum negative the cranes,” said Slagle. system will be rebuilt or modernized, moment.” Typically, each haunched and nearly half of the system’s girder was made in 120-ft lengths, but Once the girder was released from the 117 miles of existing roads will be one was 138 ft long. crane, the contractor connected the widened or have lanes added. post-tensioning ducts between the beam Falsework Supports Beams ends. Formwork then was placed, and “Most of the tollway system was For the post-tensioned spans, Walsh the closure pour was made. “There’s constructed nearly 50 years ago and used falsework to support one end of a nominal 1-ft gap at the splice,” said has reached its design life,” explains Lis the beams during erection, so that the Slagle. “We coupled the ductwork, set Henderson. The growth of the northern beam rested on both a pier and the all the reinforcement and formwork, and Illinois region also has brought on the falsework. Two beams would extend then made the closure placements across need for improvements. toward each other, leaving space all six beam lines at once. That way, the between for a drop-in segment with a closure acted as a monolithic diaphragm.” The Tollway already has committed length varying between 124 and 150 ft. $3.6 billion worth of improvements The drop-in segment was lifted with a Once the concrete in the closure reached to contract, including $2.8 billion in crane at each end. A temporary strong- 5000 psi compressive strength, the construction work. “We’re trying to back was clamped to each end of the post-tensioning contractor installed the deliver as many of the benefits to the drop-in segment to provide an overhang strand and tensioned it with hydraulic public as soon as we can.” that rested on the adjoining beam end. jacks. Each girder had four ducts for

ASPIRE, Spring 2008 | 31 Ongoing construction of the piers.

the post-tensioning strand, explains “We had to purchase seven additional Slagle. “Generally speaking, the ducts acres,” says Terry Muntz, Vice President are arranged to be high over the piers of Operations at PEC’s Blackstone, and low at mid-span—points where the Illinois, plant. “Half of the land went beam is in tension.” for storage of product and the other half was used to build the two casting beds.” Each casting bed is 400 ft long by 20 ft wide by 10 ft deep.

The prairie winds blow strongly in Blackstone, so PEC built the beds in-ground to help keep the concrete warm during casting. The in-ground casting beds also permitted PEC to use shorter travel lifts. “This way we only had to lift the product the height of the beams before we could carry them,” says Muntz. “If we had a 10-ft-high form and a 10-ft-deep beam, we’d need to lift the beams to a point 20 ft above ground.” Deck placement of unit 4 southbound bridge. Deck was cast in a specific sequence Training the new employees was the to avoid deck cracking over the piers. biggest challenge, he adds. They also had to create a new safety plan to deal with the larger beams. The largest beams the company had previously cast were 72 New Forms Created in. deep, and the deepest beams at the The $24-million contract for the precast, DPRV Bridge were 120 in. deep. prestressed concrete girders produced the largest-ever contract for Prestress Tollway officials take justifiable pride in Engineering Corp. (PEC), which is Illinois’ their new bridge. “This bridge provides largest precast concrete bridge supplier. a great benefit to the driving public,” To handle the order, the precaster built said Lis Henderson, a spokesperson for two in-ground casting beds in 5 months, the Tollway. bought three beam forms, doubled its workforce to 200 people, and purchased For more information on this or other eight 10-axle trailers. projects, visit www.aspirebridge.org.

Minimal Environmental Impact

The spliced girder design allowed the Tollway Tollway. “We were able to affect only 8.77 as it is,” says Kovacs. “We identified the to use spans long enough to minimize acres during construction and only 3.87 dragonfly and studied its habitat. So we the bridge’s impact on the wetlands acres permanently. We built 34 piers, and 16 built the bridge 10 ft higher to keep cars out through which it passes. The bridge and its of those are in wetland areas.” of the path of the dragonfly.” At its highest construction had to meet environmental point, the bridge is 90 ft above grade. requirements set by the U.S. Army Corps of Protected Species Engineers, the Illinois Department of Natural Believe it or not, a rare dragonfly helped The area is also inhabited by the Blanding’s Resources, the Illinois EPA, and the U.S. Fish & influence the design of the DPRV Bridge. The Turtle, which needs to be protected. Colin Wildlife Service. area around the bridge serves as habitat for Makin, the Tollway’s Deputy Program Manager the Hine’s Emerald Dragonfly, which was for Bridges, said the turtles have been “This design allowed us to come in under listed as an endangered species in 1995. found and fitted with electronic locators. If the wetland acreages that we could impact a Blanding’s turtle roamed too close to the on both a temporary and permanent basis,” “The Hine’s Emerald Dragonfly is one of construction area, a group of environmentalists says Paul Kovacs, Chief Engineer for the the reasons the bridge was built as high would pick up the turtle and relocate it.

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Bridge-Brick CS2.indd 1 7/31/07 9:41:45 AM ASPIRE, Spring 2008 | 33 ’ AMERICAN SEGMENTAL BRIDGE INSTITUTE S First 20 Years and1 The Future By Linda Figg, FIGG and Ray McCabe, HNTB

In 2008, the American Segmental Bridge Institute (ASBI) will celebrate its 20th anniversary by hosting an international symposium on “Future Technology for Concrete Segmental Bridges” in San Francisco, California, on November 17-19, 2008. The expanded 3-day program will culminate the 20th anniversary celebration of ASBI and will feature keynote presentations by widely recognized United States and international bridge engineers, along with a tour to view the construction of the San Francisco-Oakland Bay Bridge. ASBI has come a long way over the years, growing to 51 organizational member companies and a total of 264 engineers, contractors, and suppliers—all focused on the segmental bridge industry. The 2007 convention, held in Las Vegas, Nevada, attracted 415 bridge industry professionals, the largest ASBI convention to date. ASBI has achieved many

ASBI’s founding members goals and is well poised to support the segmental bridge –— A moment in history industry in the future. Standing (from left to right): W. Burr Bennett Jr., consultant; Robert P. McCrossen, ASBI was founded in 1988 through the vision and leadership material supplier; Clifford L. Freyermuth; of Eugene C. Figg Jr. In remembering those early days, Linda Eugene C. Figg Jr., consultant; Raymond Figg reflects, “My father brought me into his office one day to Schmahl, contractor; Juergen L. Plaehn, material supplier; Seated (from left to right): share his ideas for what would become the American Segmental David T. Swanson, material supplier; W. Bridge Institute. He believed that a focused organization with Jack Wilkes, consultant; and Gary L. Peters, people from various industry interests would bring the greatest contractor. success to advancing segmental bridge technology. He thought Cliff Freyermuth would be excellent to manage the organization with his strong background with the Precast/Prestressed Concrete Institute and Post-Tensioning Institute. And now, 20

Background photo courtesy years later, ASBI has made significant achievements and Cliff of Kiewit Pacific Company. Freyermuth has been a strong and dedicated day-to-day leader.” Cliff Freyermuth Manager, ASBI

The original group gathered in Wichita, Cliff Freyermuth Kansas, to discuss how the segmental ASBI has achieved many goals set out bridge industry could come together in 20 years ago. Since the organization one organization to provide a resource was founded, the day-to-day operations ASBI Training Session Exam on Grouting to advance the benefits of concrete of ASBI have been managed by Cliff Certification at the University of Texas. segmental bridges in the United Freyermuth. In this anniversary year, it States. Each of the individuals in the is with pleasure that we pay tribute to founding group saw the benefits of him for his dedicated service to ASBI. Photo: T.Y. Lin International. segmental bridges and the increasing While Cliff is concluding his tenure at level of interest in segmental bridges ASBI this year, he will continue to be nationwide. The vision was to create a an important voice in the industry and unique organization that would bring work in consulting. He came to ASBI together all areas of interest—owners, after 12 years as Manager of the Post- engineers, designers, contractors, and Tensioning Institute, 5 years as Director material suppliers. ASBI’s founding of the Post-Tensioning Division of the members were a cross-section of Prestressed Concrete Institute, 6 years interested leaders, who set the framework for how the organization and industry could grow and succeed. BRIDGE TOURS AND CONVENTION HOST CITIES In ASBI’s 20-year history, the industry has Over the years, ASBI has held annual conventions in 19 distinctive destinations. evolved and advanced in many positive Bridge tours of nearby significant segmental bridges have been included. The bridges are ways. Many successful and beautiful typically under construction or recently completed, and serve as a ‘classroom in the field’ segmental bridges have been completed illustrating various aspects of segmental bridge design and construction. and more are being designed and built by ASBI member firms. Segmental 2007 Hoover Dam Bypass Bridge 1997 U.S. 183 Viaduct bridges are increasingly becoming a Las Vegas, Nevada Austin, Texas preferred bridge technology by many owners. Segmental bridges have been 2006 Otay River Bridge 1996 Seabreeze Bridge completed throughout the United La Jolla, California Orlando, Florida States and continue to set new records 2005 Woodrow Wilson Bridge 1995 Puyallup River Bridge for span lengths, to introduce new Washington, D.C. Seattle, Washington technologies, to be cost efficient, and to capture pleasing aesthetic qualities. 2004 Lee Roy Selmon Expressway 1994 Chesapeake & Delaware Tampa, Florida Canal Bridge Grouting Certification 2003 High Five Interchange Philadelphia, Pennsylvania In order to continue to strengthen the Dallas, Texas industry and provide quality measures 1993 Acosta & Dame Point Ponte Vedra, Florida consistent with our goals, ASBI organized 2002 San Francisco-Oakland Bay Bridge and began offering grouting certification & Benicia-Martinez Bridge 1992 Natchez Trace Arches training in 2001. The purpose of the San Francisco, California Nashville, Tennessee training is to provide supervisors and inspectors of grouting operations with 2001 Creve Coeur Lake 1991 San Antonio “Y” the training necessary to understand Memorial Park Bridge San Antonio, Texas and successfully implement grouting St. Louis, Missouri 1990 Keys Bridges & specifications for post-tensioned structures. Over 1100 professionals have 2000 AirTrain JFK Light Rail Dodge Island Bridge completed this training, which is offered Brooklyn, New York Miami, Florida annually, bringing improved construction 1999 Sidney Lanier Bridge 1989 Pine Valley Creek Bridge to segmental bridges. In 2008, the Amelia Island, Florida San Diego, California grouting training and certification will be offered on April 14 and 15 at the J.J. 1998 Central Artery Pickle Research Campus in Austin, Texas. Boston, Massachusetts

ASPIRE, Spring 2008 | 35 with the Portland Cement Association, in 2004 for “his many contributions to and 6 years in bridge engineering with the development and implementation the Arizona Highway Department in of post-tensioned concrete building and Phoenix, Arizona. segmental bridge design techniques and construction specifications.” As Cliff has been responsible for or had the current ASBI President Ray McCabe significant involvement in over 34 major reflects on Cliff’s years of service, publications in the industry. He led the “We appreciate all the contributions development of the Precast Segmental and leadership that Cliff has provided Box Girder Bridge Manual published by over the past 20 years to ASBI. ASBI PCI and PTI in 1978. He was Principal continues to grow and Cliff has been 2006 ASBI Leadership Awards: Cliff Investigator for the NCHRP Project for instrumental in the development of this development of the 1989 AASHTO forward thinking bridge institute.” Freyermuth for Outstanding Career Guide Specifications for Design and Contributions to the Segmental Concrete Construction of Segmental Concrete Industry as ASBI Executive Vice President. Bridges, and served as the Chairman Also recognized are (bottom left to of the committee that developed three right) Guido Schwager, segmental/ editions of the PTI Recommendations cable-stayed bridges; John Armeni, for Stay-Cable Design, Testing and Chair, ASBI Committees on Membership Installation. His commitment and and Construction Practices; Hala Elgaaly, knowledge of the industry have been Chair, ASBI Bridge Award of Excellence, significant contributing factors in ASBI’s Board of Directors; Paul Liles, ASBI success. Cliff’s career accomplishments President 2005-2006; (top left to have been recognized by many organi- zations, including ASBI itself in 2006 right) Steven Stroh, concrete segmental/ with an ASBI Leadership Award for extradosed bridges; W. Denney Pate, Outstanding Career Contributions to concrete segmental/cable-stayed bridges; the Segmental Concrete Bridge Industry; Alan Moreton, design/construction PCI’s Charles C. Zollman Award in 1999; segmental concrete bridges. American Concrete Institute’s (ACI) Cliff Freyermuth receiving 1999 PCI Henry C. Turner Medal in 1991; and Charles C. Zollman Award from John ACI’s Arthur R. Anderson Award Dick, PCI Structures Director.

In 2003, in order to recognize and celebrate segmental bridge owners who have achieved outstanding projects, ASBI created the Bridge Award of Excellence program. Every 2 years, award-winning bridges are honored during the ASBI convention and are featured in Concrete Products magazine.

2003 WINNERS I-25/I-40 Interchange, Albuquerque New Mexico Department of Transportation Vietnam Veterans Memorial Bridge, near Richmond Virginia Department of Transportation I-90/I-93 Interchange, Boston Massachusetts Turnpike Authority Broadway Bridge, Daytona Beach Florida Department of Transportation Foothills Parkway Bridges (#9 & #10), Blount County, Tennessee Eastern Federal Lands, Highway Division, FHWA Smart Road Bridge, near Blacksburg Virginia Department of Transportation

36 | ASPIRE, Spring 2008 ASBI’s Future Vision current design, construction, and The Board of Directors has identified construction management procedures, LEADERSHIP strategic steps to continue to look to and evolve new techniques that will ASBI has been led by some of the strongest the future for continued growth and advance the quality and use of concrete supporters of the segmental bridge industry advancement of segmental bridges. Con- segmental bridges. ASBI is a unique in the United States, each focusing on unique crete segmental bridges will continue to organization in that all components of issues and opportunities and bringing their advance and lead the industry in new the bridge construction industry are own signature to the organization while technologies for longer lasting bridges. included as members. under their leadership. Leaders included The International Symposium to be held representatives from owners, consulting November 17-19, 2008, will feature This fall, ASBI will bring on a new firms, contractors and material suppliers, some 64 topics and speakers highlighting manager to begin the next 20 years each contributing to ASBI and advancing extraordinary achievements in the bridge and work with future ASBI presidents. the industry in their own way. industry. A committee, led by Ralph Salamie of Kiewit, is developing details on the Term of Office President The American Segmental Bridge Institute manager’s position and identifying 1989 – 1990 W. Jack Wilkes, Consultant will continue providing a forum where interested candidates. For more informa- owners, designers, constructors, and tion, contact Ralph at (360) 693-1478 or 1991 – 1992 Gary L. Peters, Contractor suppliers can meet to further refine [email protected]. David Swanson, 1993 – 1994 Material Supplier 1995 – 1996 Man-Chung Tang, Consultant 1997 – 1998 Eugene C. Figg Jr., Consultant James E. Roberts, 1999 – 2000 Transportation Official (owner) Ronald J. Bonomo, 2001 – 2002 Material Supplier 2003 – 2004 R. Craig Finley Jr., Consultant Paul V. Liles Jr., 2005 – 2006 Transportation Official (owner) 2007 – 2008 Raymond McCabe, Consultant

2005 WINNERS 2007 WINNERS Victory Bridge, Sussex County Lee Roy Selmon Crosstown Expressway Expansion, Tampa New Jersey Department of Transportation Tampa Hillsborough Expressway Authority, Florida Four Bears Bridge, New Town Otay River Bridge, San Diego County North Dakota Department of Transportation California Transportation Ventures AirTrain JFK, Brooklyn, New York Penobscot Narrows Bridge & Observatory, near Bucksport Port Authority of New York & New Jersey Maine Department of Transportation Creve Coeur Lake Memorial Bridge I-76 Susquehanna River Bridge, York and Dauphine Counties Missouri Department of Transportation Pennsylvania Turnpike Commission Sidney Lanier Bridge, Brunswick Second Vivekananda Bridge Tollway, India Georgia Department of Transportation Second Vivekananda Bridge Tollway Company Private Ltd. I-95/Palm Beach Interchange Woodrow Wilson Memorial Bridge Florida Department of Transportation FHWA, Departments of Transportation of Virginia, Maryland, and District of Columbia Tarrango Bridge, Mexico City Government of Mexico City Panama Canal Second Crossing, Paraiso Ministry of Public Works, Panama Maroon Creek Bridge

R eplacementby Thomas W. Stelmack, Parsons

The residents and visitors at the world- class ski resort of Aspen, Colorado, have waited years for the ‘Entrance to Aspen’ project to be completed. This consists of the reconstruction of State Highway 82 as the primary access road and one of only two routes into the town from the west. The highway crosses the wide and deep Maroon Creek basin at the town limits on the oldest bridge in service on the Colorado state highway system. Due to its historical significance, the existing bridge is listed on the National Register of Historic Places.

Originally constructed as a railroad trestle bridge in 1888, the Colorado Midland Railroad Bridge became the property of what was then called the Colorado Department of Highways in 1927. The Maroon Creek Bridge was converted for highway use in 1929 and A rendering of the completed project widened in 1963 to its current width of was prepared for approval by the 30 ft by adding outrigger struts to the CDOT and local agencies. original A-frame trestles. Since then, the timber bridge deck with asphalt has been replaced once and repaired several times. To this day, the structure continues to require high maintenance

Maroon Creek Bridge Replacement / State Highway 82, Aspen, Colorado profile Engineer: Parsons Transportation Group, Denver, Colo. Prime Contractor: BTE Concrete/Atkinson Construction JV, Glenwood Springs, Colo. Contractor’s Engineer: McNary Bergeron & Associates, Denver, Colo. Construction Inspection: Carter Burgess, Denver, Colo. Concrete Supplier: Lafarge North America, Carbondale, Colo.

38 | ASPIRE, Spring 2008 A view of the nearly completed first cantilever shows the wide deck overhangs, deck ribs, and the adjacent existing historic bridge.

by the Colorado Department of Transportation (CDOT), which lowered the sufficiency rating to 24 because of substructure repairs to arrest scour and damaged pier foundations. This forced heavy trucks to be detoured around the bridge via the secondary route while repairs were made.

In 1990, the CDOT recognized the need to replace the existing bridge and completed the design of twin, three- span steel box girder bridges. The twin- bridge concept, however, was never built due to public concerns regarding the number of lanes, alignment, and impact the construction and resulting traffic would have on the environment.

Critical Issues and Project Goals After extensive study, several requirements were identified and considered in the design of the replacement bridge. The primary issues were environmental impact, aesthetics, and impact on the traveling public using SH 82. These were added to CDOT’s original project goals of cost,

Cast-in-place, concrete, segmental box girder bridge crossing Maroon Creek / Colorado Department of Transportation, Region 3, owner Post-Tensioning Supplier: VSL, Hanover, Md. Form Traveler Supplier: Mexpressa, Xochimilco, D.F., Mexico Bridge Description: Three-span, cast-in-place, balanced cantilever segmental box girder with a main span of 270 ft, end spans of 170 ft, and a width of 73 ft Bridge Construction Cost: $13.97 million

ASPIRE, Spring 2008 | 39 ‘It’s also going to be a very durable and long-lasting bridge.’

maintenance, and durability in the flanked by equal 170-ft-long side spans. evaluation of the alternative structures. The single cell box girder is 73 ft wide and is a constant 13 ft 6 in. deep, with During preliminary design, several 19-ft-long long deck overhangs, using bridge types were identified that could ribbed elements for support of the long achieve the aesthetic goals of the slab spans. The typical segments are project, have estimated construction 15 ft long, with one deck rib in each costs within an acceptable range, and segment placed 5 ft from the leading meet the maintenance and durability edge of the segment. The segment requirements. Therefore, constructibility layout consists of a 25-ft-long pier table Form travelers were became the differentiating factor in with eight segments in the main span selection of the bridge type. cantilever and 10 segments in the side used to construct span, the last connecting directly to the the superstructure Recommended abutment segment. The two cantilevers segments from above to are connected with a 5-ft-long closure minimize impacts to the Alternative—Cast-in-Place segment at the center of the main span. environmentally sensitive Segmental Concrete creek basin and wetlands After careful evaluation of several Piers and Foundation—The piers below the bridge. alternative bridge types and construction form an ‘A’ shape with a capital section methods, a cast-in-place (CIP), segmen- at the top of the pier that is flared at tal concrete box girder bridge to be the same angle as the outriggers on built using a pair of form travelers and the existing bridge. The flared section the balanced cantilever method of provides the required connection to the construction was selected. wide box girder section, while reflecting the shape of the existing trestles. As Superstructure—The final span the lines of the capital flow into the configuration is a 270-ft-long main span pier legs, the outside face of the pier

Balanced cantilever construction of second cantilever is nearly 50 percent complete.

40 | ASPIRE, Spring 2008 An ‘Environmentally Friendly’ Bridge

The new Maroon Creek Bridge has been a successful project for Maroon Creek, with a narrow footprint in order to minimize in-stream many reasons, but none more important than its utilization of a ‘from construction activities. the top’ construction method. The wetlands in the Maroon Creek basin have been subjected to serious environmental impacts since Another challenge to the project design team was to provide the area was first settled in the 1800s. Recently completed wetlands extensive water-quality protection and a protected staging area, restoration projects include eradicating non-native plants, re-grading, while still allowing for movement of wildlife in the basin. A wildlife re-planting, and improving drainage to create a thriving riparian movement study was conducted with a three-fold purpose to: complex. Therefore, one of the major goals of the project was to • Evaluate current large mammal movement through the proposed design an economical bridge that could be constructed with minimal project area; impact to the basin. The Entrance to Aspen documents required that the new bridge be constructed with a maximum temporary • Predict how the staging and construction of the bridge replacement disturbance to wetlands of 0.2 acres, and maximum permanent could impact those movements; and displacement for piers of 0.1 acres. • Make recommendations on how to mitigate those impacts.

The balanced cantilever, cast-in-place concrete, segmental bridge The results of this study, which were included in the project plans construction technique using overhead form travelers minimized the and implemented during construction, included requirements for need for heavy cranes and allowed the majority of the superstructure special fencing, monitoring during and after construction, and construction work to be done from above. limitations on night work to minimize disruptions during nocturnal wildlife movements. A special wetland-restoration seed mix was also Detailed constructibility studies of all viable alternatives were done developed to restore disturbed areas. to determine the size and location of the cranes and other equipment for both substructure and superstructure construction, laydown areas Additional environmentally sensitive features of the bridge for materials and girders, and access roads to both pier locations. include low-energy LED lighting of the pedestrian path and the While all the alternatives could be carried out within the allowable accommodation of an 8-in.-diameter pipe inside the box girder to impact limits, the segmental alternative impacted less than half the carry reclaimed water from a new city development for irrigation of area impacted by the girder alternatives. Also, the area impacted the adjacent Aspen City golf course. for the segmental structure is constrained to the area below the bridge and around the piers—the area previously disturbed during The project has already been the recipient of CDOT’s own construction of a pedestrian bridge that was removed as part of this Environmental Award in 2007 and Pete Mertes, CDOT Resident project. Based primarily on the results of this study, the segmental Engineer, states, “it was an excellent choice of structure type to scheme was deemed to be preferable by all of the stakeholders, minimize the environmental footprint, as well as virtually avoiding including CDOT, Pitkin County, the City of Aspen, and the public. the impacts to traffic and the traveling public.” The final plans included detailed limits for the disturbance areas and also included details for a temporary construction crossing of

leg is recessed. This recess, together from the top section of the pier. The work pier areas was relocated from the with a change in concrete color within first form traveler was then erected on centerline of the structure to just outside the recess, combines to reduce the top of the pier table and the first typical the edge of the bridge. This was done visual mass of the very tall pier. The segment cast in early fall 2006. The to allow better crane access for lifting conventionally reinforced concrete segments were cast alternately on either segment materials, while keeping the pier legs are tapered in the direction end of the cantilever until reaching the overall area of impact the same. transverse to the roadway centerline eighth segment in the main span and from 10 ft at the base to 6 ft at the ninth on the side span. Although the The second cantilever was completed top and have a constant 10 ft thickness site is located at an elevation of 7900 ft, in late 2007 and the main span closure in the longitudinal direction. The pier the contractor controlled temperature in connecting the cantilevers was cast in is founded on a footing supported the segments throughout the winter by December 2007. Bottom slab tendons by twelve 4-ft-diameter drilled shafts insulating the forms and running heated were then stressed to complete the main socketed into rock approximately 20 ft glycol through pipes on the exterior span. The final closure to the second below the footing. surface of the forms. Concrete for the abutment was made in January 2008, segments was pumped from the creek which completed the segment casting a Construction Details basin with a pumper truck located near little over a year after the first segment Construction began on the piers in late the pier. The entire superstructure was was cast. Joe Elsen, CDOT Region 3 fall 2005 and continued throughout the constructed from the top, with impacts East Program Engineer expressed his winter. Once the pier was completed, to the creek basin limited to the areas satisfaction with the project, “The bridge the 25-ft-long pier table section was designated during design with one is an extremely elegant structure and the cast on falsework supported directly exception. The path connecting the two aesthetics are very pleasing. It’s also going

ASPIRE, Spring 2008 | 41 Only the final closure segment to the abutment remains as the form travelers are lowered to the ground near the pier.

to be a very durable and long-lasting will be opened to traffic completing the bridge due to the prestressing and high first phase of the ‘Entrance to Aspen.’ strength concrete.” Local agencies and ______the public have also been receptive to the new structure and are looking forward to Thomas W. Stelmack is Senior Project the day later in 2008 when the bridge Manager with Parsons, Denver, Colo.

For more information on this or other projects, visit www.aspirebridge.org.

AESTHETICS COMMENTARY by Frederick Gottemoeller

The new Maroon Creek Bridge and the former railroad trestle as a point of departure for the design of the new piers. This very ef- that it replaces present a fascinating contrast in bridge design phi- fectively provides a visual tie between the bridges in spite of the fact losophies. Happily, both will remain in place to remind engineers that that they are otherwise quite different. The long deck overhangs are there is always more than one way to bridge a gap. The original rail- another successful feature of the new bridge. Their shadows on the road bridge crosses the valley with 19 spans supported by multiple girder webs reduce the apparent depth of the girder. At the same thin steel piers. It achieves transparency because the members are time, the deep setback of the girder webs from the edges of the deck so thin that you can see right through them. The new bridge crosses reduces the shadow of the bridge on the ground. The piers them- the valley with three spans on two massive piers. It achieves transpar- selves appear heavy, particularly when seen together with the thin ency because you can see between them. Even non-engineers will steel members of the original bridge. They would have been improved find the differences between these bridges interesting and worth with thinner proportions, especially at the “knuckle” just below the thinking about. girder. However, overall this is a fine bridge. The crossing of the creek by State Highway 82 will continue to be a memorable feature of the When the railroad bridge was converted to automobile use in 1929, Maroon Creek valley. diagonal struts were added at each pier line and gave the cross section a pinched-waist silhouette. The new bridge takes this silhouette

42 | ASPIRE, Spring 2008 To Enter Visit www.pci.org PCI Select News & Events CALL FOR Select Design Awards BRIDGE DESIGN Download “Call for Entries” and “Project Credit Sheet” Follow instructions provided in the “Guidelines for Submittal” AWARDSENTRIES DEADLINE FOR ENTRIES, MAY 23,2008 Submission Projects are judged in several categories. All bridges – large and small – that satisfy particular design challenges are encouraged to be submitted.

For Questions Contact: John Dick or Chuck Merydith at PCI telephone: 312-786-0300 or write: [email protected] or [email protected]

MKT08-0046AspireAd_HALF.indd 1 3/14/08 9:13:29 AM

ASPIRE, Spring 2008 | 43 PREASSEMBLED BRIDGE Facilitates Overpass Construction by Jamie Griffin, Lloyd Wolf, Gregg Freeby, Michael Hyzak, David Hohmann, and Randy Cox, Texas Department of Transportation

The bridges incorporated pretopped U-beams, precast concrete column shells, and preassembly.

The Texas Department of Transportation (TxDOT) employs innovative techniques to accelerate bridge construction while providing durable, economical, and aesthetically pleasing solutions on a wide variety of projects. From such bridges as the Jim Cowan Memorial Bridge at Lake Belton to the Cottonwood Creek and Battleground Creek Bridges, fully precast bridge systems Typical pretopped U-beam section. have played an important role in reducing the impact of bridge construction to the traveling public in Texas’ rural areas. The design challenge was to provide an Reconstruction of I-35, the main north- aesthetically pleasing set of bridges that minimized south artery and a crucial commercial corridor in central Texas, necessitated traffic disruption. the construction of several overpasses.

Loop 340 Bridges / Waco, Texas profile ENGINEER: Texas Department of Transportation, Austin, Tex., and Structural Engineering Associates, San Antonio, Tex. PRIME CONTRACTOR: Archer-Western Contractors, Arlington, Tex. PRECASTER: Heldenfels Enterprises Inc., San Marcos, Tex., a PCI-Certified Producer PRECAST SPECIALTY ENGINEER: Structural Engineering Associates, San Antonio, Tex. PRECASTER’S ENGINEER: Unitech Consulting Engineers, San Antonio, Tex. AWARD: Co-Winner of 2007 PCI Design Award for Best Bridge with Spans Between 75 and 150 ft 44 | ASPIRE, Spring 2008 and two 48-ft 3-in.-wide frontage road of the total number of strands, previous bridges, each comprised of four 115-ft-long experience had shown success with spans crossing over I-35, were selected. up to 75 percent of strands debonded The final design for the Loop 340 bridges in prestressed concrete beams. This incorporated pretopped U-beams, precast experience was supported by research concrete column shells, and an innovative conducted at the University of Texas at off-site preassembly method to reduce the Austin confirming the successful use of impact to motorists caused by superstructure 75 percent debonding and by further construction over the busy lanes of I-35. calculations to ensure that the beams would have adequate shear resistance. Pretopped U-Beam Design The Texas chapter of the Precast Concrete In order to facilitate inspection and reduce Manufacturers Association (PCMA), the chance of honeycombing in the together with TxDOT and partners in bottom slab, the beam fabricator cast the industry, developed a superstructure system bottom flange and webs as the first step to be used for the first time nationally in of a two-stage placement. In the second the construction of the Loop 340 bridges. stage, the fabricator placed the 7-in.-thick New beams were developed from TxDOT top flange. After the specified release standard precast, prestressed concrete strength was attained, the prestressing U-beams that incorporated a 7-in.-thick top strands were released and the beams were flange cast by the beam fabricator. Plans transported to the contractor’s staging yard specified an additional 4 in. of concrete near the construction site, where the final slab to be placed by the contractor at the 4-in.-thick topping was placed. off-site casting yard near the construction site. The top flange plus the 4-in.-thick pretopping provided a precast slab and reduced site-cast concrete to a narrow closure pour between pretopped beams. The exterior beam design included an overhang, also precast off-site, which eliminated the need for form removal over traffic, thereby reducing construction time and increasing worker safety. This construction provided TxDOT with a unique opportunity to utilize accelerated The pretopped U-beam is comprised of a construction techniques in a dramatically 34-in.-deep precast, prestressed concrete different environment from the rural areas beam with a 4-in.-thick topping slab added in which these techniques had previously at the off-site casting yard, for a total final been employed. Here, the design section depth of 38 in. The beams are challenge was to provide an aesthetically spaced at approximately 8 ft on center and pleasing set of bridges that minimized utilize 0.6-in.-diameter strands on a 2-in. traffic disruption to the busy interstate grid. With up to 77 prestressing strands and by reducing construction time within the concrete strengths of 6500 psi at release right-of-way of I-35. These bridges would and 7400 psi final, the beams can span up then be used as prototypes for many to 115 ft, for a span-to-depth ratio of 36.3. such overpasses along the I-35 corridor. The design required debonding up to 75 TxDOT identified four candidate bridges percent of the prestressing strands in the on Route 340 Loop near Waco for which beam ends to satisfy allowable tensile the prototype design would be formulated. stresses at release. While AASHTO limits Pretopped U-beam construction Two 58-ft 3-in.-wide mainlane bridges debonding to no more than 25 percent sequence.

Precast, prestressed, pretopped, concrete U-beams / State of Texas, Austin, Texas., OWNER BRIDGE DESCRIPTION: Two mainlane and two frontage road bridges comprised of newly developed precast, pretopped U-beams spanning 115 ft over I-35. Precast substructure features individual columns with no bent cap. Superstructure completely preassembled in off-site casting yard to obtain final elevations and grading prior to placement on-site. STRUCTURAL COMPONENTS: Precast, pretopped U-beams incorporating a 4-in.-thick pretopped slab from the beam fabricator, with an additional 4-in.-thick slab cast by the contractor in an off-site precasting yard. Individual precast concrete columns with no bent caps. BRIDGE CONSTRUCTION COST: $8.4 million

ASPIRE, Spring 2008 | 45 Formliners were used to simulate limestone blocks for the column shells. The column shells were precast for rapid erection.

Precast Column Shells Prefabricated Bridge In keeping with the goals of reducing Construction System construction time within the right-of-way Among the most unique developments and reducing impact to the motoring featured in the construction of the Loop public, column shells were precast at 340 bridges was the off-site preassembly the contractor’s off-site staging yard and of the bridge spans. In order to address then moved into position within the grading issues when adding the final right-of-way. The columns were precast 4-in.-thick slab, the contractor erected full height using a hollow rectangular the beams on temporary supports section and featuring a unique formliner constructed to simulate the permanent to produce the appearance of large supports on which the beams would limestone blocks. Outer columns were ultimately rest. The supports were designed with a tapered width for designed to provide the same cross- added aesthetic value. slope, longitudinal slope, and relative elevation between beams as specified Once ready for placement, the for the finished structures. column shells were moved into their Beams were preassembled for casting final locations within the right-of-way The beams were first assembled side-by- the deck. and placed on top of a conventional side on temporary supports and bearing drilled shaft with a top-cast footing pads. The contractor then placed and a projecting reinforcing steel cage. reinforcing steel for the remaining 4-in.- Elevations were adjusted with the aid of thick slab, and formed and placed the leveling pads. Infill concrete completed final topping slab and outside curbs, the precast column assembly. Due to using blockouts to form the longitudinal the wide spacing of the pretopped and transverse closure strips that would U-beams, each line of beams was able be cast after the beams were moved to to be directly supported on individual their final locations. The topping was columns, eliminating the need for a bent graded using a screed to help achieve cap. Bent cap construction constitutes a the correct elevation and to account for considerable amount of construction differential camber between beams. and curing time within the right-of-way, so elimination of the bent cap through Once the final 4-in.-thick topping cured A 4-in.-thick topping was cast on the the use of the individual columns further and the bridge rail was attached, the beams before onsite erection. reduced construction time. beams were transported from the

46 | ASPIRE, Spring 2008 TxDOT developed a prefabricated system appropriate for construction in high-traffic areas. off-site staging yard to the bridge concrete. Grinding was permitted to a the bridges still proved economical. construction site where they were placed maximum depth of 1/2 in. in order to Indirectly, the time saved by motorists on the individual columns. The initial achieve final required grades, but the and commercial operators in the form night-time placement rate was one span pretopped U-beams aligned so well in of reduced construction-related delays per night, but ultimately increased to their final positions that no grinding was further validated the increase in cost. two spans per night as the contractor necessary. After the closure strips cured, became more familiar with the system. the bridge was ready for traffic. With the successful construction of An exterior beam with final deck and the Loop 340 bridges, TxDOT has not curbs weighed approximately 148 tons. Conclusion only developed a prefabricated bridge The preassembled prefabricated bridge system appropriate for construction in Pretopped beam placement marked the system proved to be a successful some high-traffic areas, but has also only times during which the mainlanes alternative to traditional construction found this system effective in mitigating of I-35 were closed to traffic. After all over high-traffic roadways. Although the damage to the local environment. As beams were in position forming the preassembly did incur additional costs, at more of these bridges are commissioned bridge superstructure, the contractor $86.06 psf compared to $62.00 psf for along interstates and in rural areas, we placed reinforcement in the longitudinal conventional prestressed concrete beam look forward to continuing to provide and transverse closure strips and placed bridge construction, the direct cost of unique solutions designed to minimize concrete, tying the bridge together. the impact of bridge construction to the Stay-in-place forms were used in the motoring public. closure strips. Since the forms prevented ______concrete from leaking onto the lanes below, I-35 was opened to traffic during Jamie Griffin, Engineering Assistant; the placement of the closure strip Lloyd Wolf, Bridge Design Group Leader; Gregg Freeby, Bridge Design Group Leader; Michael Hyzak, Senior Bridge Beams were erected at night. Design Engineer; David Hohmann, Design Section Director; and Randy Cox, Bridge Division Director, are all with the Texas Department of Transportation.

Pretopped U-beams were joined in the field with longitudinal and transverse For more information on this or other closure placements. projects, visit www.aspirebridge.org.

Aesthetically Pleasing Solution with Minimal Impact

Accelerated construction techniques and simulate limestone blocks provided the site. The contractor was better able to enhanced bridge aesthetics have long surface texture that completed the unique contain construction waste at the casting been touted as a means of reducing appearance of the substructure. This careful location than would have been possible construction-related delays and improving attention to aesthetic detail produced the in conventional on-site construction at a the appearance of our local roadways. graceful and dynamic style of the Loop 340 high-speed interstate highway, thereby The Loop 340 bridges gracefully combine bridges and served as further evidence that preventing excessive dust and other waste rapid construction techniques and striking a focus on function and economy does not from affecting the local community and architectural features to produce a set exclude the addition of aesthetic features. interstate traffic. of bridges remarkable in both form and function. The aesthetics concept, developed The preassembled superstructure and The Loop 340 bridges have thus by TxDOT engineers, incorporates sloped precast columns reduced time spent within incorporated the elements of exterior columns, slender beams, and a short the right-of-way, improved worker safety, sustainability—they not only significantly sloped overhang reflecting the slope of the and allowed for greater environmental diminished construction-related delays and exterior columns. A new open steel railing, controls. Since most construction activity the related impacts to the community, but used for the first time nationally on these occurred at the off-site casting yard, little have provided a series of attractive and bridges, was also developed to complement construction waste was introduced into the distinctive bridges that are the subject of the bridge aesthetics. Large formliners to environment surrounding the construction pride for the surrounding areas.

ASPIRE, Spring 2008 | 47 Aircraft Bridges Take Off by Ted Bush, Kent Bormann, and Rob Turton, HDR Inc.

Taxiway Sierra Underpass / Sky Harbor Airport, Phoenix, Arizona profile ENGINEER: HDR Inc. CIVIL ENGINEER: Dibble Engineering, Phoenix, Ariz. PRIME CONTRACTOR: Kiewit Western Co., Phoenix, Ariz. AWARDS: 2007 American Public Works Association Project of the Year (Arizona); 2007 Southwest Contractor Project of the Year; 2007 Associated General Contractors Project of the Year (Arizona)

48 | ASPIRE, Spring 2008 loads include the usual wind, thermal, and seismic considerations that are applied in accordance with AASHTO specifications.

Structural components have unique design considerations. For example, the deck design is more apt to be controlled by punching shear than flexure due to the heavy wheel loads. Additional considerations include provisions for edge curbs, to prevent aircraft from sliding off the bridge during icy or windy conditions, and fencing to prevent vehicles or pedestrians from gaining access.

Sky Harbor Reconstruction An example of how these considerations A five-span, cast-in- are addressed in the field can be place, post-tensioned seen in the $35-million Taxiway Sierra box girder bridge Airport administrators are commissioning Underpass reconstruction at Sky carried the taxiway more bridges than ever before to Harbor International Airport in Phoenix, across Sky Harbor handle airplane traffic, and this trend Arizona. Airport administrators wanted to reconstruct the existing taxiway, Boulevard at the Sky will continue. Airport bridge design including replacing the pavement and Harbor International requirements differ from highway and two single-span, reinforced concrete, Airport. Photos: railroad designs due to their applications, geometries, and rules set out by the rigid-frame structures. Richard Strange.. Federal Aviation Administration. But they also must meet the same goals as Working with the City of Phoenix any bridge in providing a safe, long- Aviation Department, designers lasting, and low-maintenance structure. established three key goals: 1. Minimize interruptions to oper- Site constraints are forcing airports to ations during construction. Shutting build runways at greater distances from down the existing taxiway would terminals, and to shuttle planes over increase congestion on the other runway and taxiway bridges to access airside routes, and drilling operations them. These same constraints also create for foundation construction and the challenges for bridge designs. Their erection of falsework would complicate Taxiway at geometry must accommodate the largest landside access to the terminals. airplane type envisioned to use the 2. Create a design that was aes- structure, as defined by wingspan and Sky Harbor thetically compatible, cost-effective, tail height. A “safety area” that increases and low-maintenance. The nearby the width requirement is also desirable. International Taxiway Tango Underpass served as a standard, having been constructed with Airport in Phoenix These designs are also governed by cast-in-place, post-tensioned concrete function. For example, impact loads box girders. The bridge had experienced shows how concrete are significantly higher for runways and minimal service issues during the past taxiways than highways, and aircraft 15 years. designs can meet braking exerts substantial forces, which typically control lateral load for 3. Eliminate the potential for conflict the growing need substructure design. Other non-gravity with future facilities. Parking was

Cast-in-place, post-tensioned concrete box girder / City of Phoenix Aviation Department, OWNER POST-TENSIONING AND REBAR INSTALLER: Paradise Rebar, Phoenix, Ariz. POST-TENSIONING AND REBAR SUPPLIER: Consolidated Rebar Inc., Phoenix, Ariz. CONCRETE SUPPLIERS: AZ Portland Cement, Phoenix, Ariz.; Salt River Materials Group, Phoenix, Ariz.; and Rinker Materials, Phoenix, Ariz. BRIDGE DESCRIPTION: Five-span, cast-in-place, post-tensioned concrete box girder STRUCTURAL COMPONENTS: Cast-in-place, five-span superstructure, pier bents, columns, drilled shaft foundations, and cantilevered abutments BRIDGE CONSTRUCTION COST: $13 million ASPIRE, Spring 2008 | 49 The substructure features four piers and two abutments, supported on deep- foundation cast-in-place drilled shafts. The columns at the outside pier lines are much wider than the interior pier lines to accommodate braking forces.

Nonintegral abutments were chosen due to the bridge’s length. A 5-ft-thick stemwall and two rows of drilled shafts were used to accommodate the live- load surcharge from the approaching aircraft. Fortunately, as Phoenix is in a low-seismic region, seismic loads were not a significant consideration.

The structure was designed to support a gross aircraft weight of 1.5 million lb, plus a The approach slab at each end of the 30 percent impact factor. Photo: HDR Inc. bridge required a thickness of 20 in. to meet flexural demands from aircraft loads. Anchor slabs also were provided available beneath the Taxiway Tango Conventional design techniques were between the taxiway pavement and the Underpass, and the owners wanted used to distribute live loading across approach slabs. the same revenue-generating option the bridge deck, and the 15-in.-thick available for the Sierra project. deck slab was sized for punching shear Longitudinal and transverse construction and flexural requirements. Transverse joints were an important consideration, Three superstructure types were flexural reinforcement in the girder due to the continuous nature of the considered: a cast-in-place, post- was determined using various possible structural system and the sheer expanse tensioned concrete box girder to aircraft landing gear configurations. of the girder. Considerable time replicate the Taxiway Tango Underpass Drop beams were added at taxiway- was spent detailing the location of design; precast, prestressed concrete lighting locations to effectively transfer construction joints in the construction I-girders; and precast, prestressed loads to the adjacent girders. of the continuous structure. All bridge concrete box girders. Steel girders were expansion and contraction movements not considered due to the relatively 3-D Modeling were accommodated at expansion joints high cost of steel in the area and the Verifies Design at the abutments. Expansion joints, incompatibility with nearby concrete with a 3-in. width, were also provided bridges and buildings. The girder design was accomplished using traditional techniques accounting between the anchor slabs and approach for the number of girder webs within slabs, and doweled construction joints Each option provided advantages, and between the anchor slabs and taxiway they were all factored into the evaluation the footprint of the landing gear. This distribution factor was verified by three- pavement accommodate any taxiway including cost, closure times, under-deck pavement movement. potential, constructibility, aesthetics, and dimensional, finite-element modeling. serviceability. Ultimately, replicating the The design aircraft was positioned transversely across the full bridge width Several additional constructibility issues Taxiway Tango Underpass design was were addressed during design. Heavy selected for the structure, which spans to determine the extreme live-loading effects. A girder web spacing of 5 ft 11 reinforcement requirements at the Sky Harbor Boulevard and provides three pier caps to column connections and interior spans for future under-deck use. in. and a total post-tensioning jacking force of 87,800 kips was required to abutment anchorages required special support the bridge weight and design detailing to avoid congestion and ensure The 406-ft-long, design-build project adequate concrete consolidation. Other features five continuous spans of post- aircraft. tensioned concrete box girders. The bridge was designed to be 214 ft wide to meet the safety area requirement for Cast-in-place drilled shafts, columns, and Group V aircraft and to support a gross abutments were used for the substructure. aircraft weight of 1.5 million lb using Photo: HDR Inc. the wheel configurations for a Boeing 747-400. A vertical force equal to 30 percent of the design aircraft’s weight was added to the live load to account for impact, while a longitudinal braking force equal to 75 percent of the design aircraft weight was applied.

50 | ASPIRE, Spring 2008 construction considerations included bridges, compared to those designed for are understood can ensure the proper airside and landside staging/phasing highways and railroads. Factors that must type, size, and location for the bridge. requirements, foundation construction, be addressed include unusual design Working as a team with the owner, and requirements for sequencing, false- specifications, requirements for airside contractor, and key suppliers will work construction, and post-tensioning and landside geometry, and designing save time and cost while leading to a operations. structural components to transfer successful project. large aircraft loads. These projects are ______Sequencing Was Critical becoming more commonplace, creating Ted Bush, Structural Engineer; Kent Removal of the existing bridge also had more opportunities for designers who Bormann, Senior Bridge Engineer; and Rob Turton, Vice President and National to be addressed. The same detour that understand the unique conditions they represent. Technical Director for Bridges are all with was created to facilitate demolition was HDR Inc. also used during falsework construction. For more information on this or other Early discussions with the owner and Construction sequencing of the new projects, visit www.aspirebridge.org. bridge was planned to minimize obstacles local officials so that all considerations for users and reduce detour time. In the first phase of work, drilled shafts for the deep foundations were constructed, after which all substructure elements, including abutments, abutment walls, and pier columns, were built.

Falsework was erected for the construction of girder soffit and web stems, with transverse joints provided to aid sequencing of the work. Crews first erected falsework for the two end spans of the bridge, which required openings

Deck concrete placement was carefully sequenced longitudinally and transversely. Photo: HDR Inc. for maintenance of traffic on Sky Harbor Boulevard. This was accomplished by diverting traffic with a temporary detour through the infield. Upon completion, traffic was reverted to allow erection of falsework for the interior spans.

Deck concrete was placed in a patch- work sequence both longitudinally and transversely to maximize construction efficiency and account for staged construction efforts with respect to stress and camber.

The design of the Taxiway Sierra Underpass shows some of the unique considerations required for aircraft

SPIRE_adfinal.indd 1 ASPIRE, Spring3/3/08 2008 6:43:22 | PM51 CONCRETE CONNECTIONS

Concrete Connections is an annotated list of websites where information is available about concrete bridges. Fast links to the websites are provided at www.aspirebridge.org.

In this Issue Bridge Research http://trb.org/news/blurb_detail.asp?id=1373 http://ntlsearch.bts.gov/tris/index.do NCHRP Report 480, A Guide to Best Practices for The National Research Information System provides a Achieving Context-Sensitive Solutions focuses on how state bibliographic database of over 640,000 records departments of transportation and other transportation of published research for all modes of disciplines and agencies can incorporate context-sensitive solutions transportation. into transportation project development. The guide is applicable to the variety of projects that transportation www.trb.org/CRP/NCHRP/NCHRPprojects.asp agencies routinely encounter. This website provides a list of all National Cooperative Highway Research Projects (NCHRP) since 1989 and their www.tfhrc.gov/structur/pubs/07024/Index.htm current status. Research Field 12 – Bridges generally lists This site provides a pdf version of the report titled “Flexural projects related to bridges although projects related to Capacity of Fire-Damaged Prestressed Concrete Box concrete materials performance may be listed in Research Beams.” Field 18 – Concrete Materials. Some completed projects are described below: www.dot.state.co.us/marooncreek/ This Colorado Department of Transportation website http://trb.org/news/blurb_detail.asp?id=3257 contains additional information about the history, NCHRP Report 517, Extending Span Ranges of Precast design, and environment of the Maroon Creek Bridge Prestressed Concrete Girders, contains the findings of replacement. research performed to develop recommended load and resistance factor design procedures for achieving longer www.fhwa.dot.gov/environment/ecosystems/ spans using precast, prestressed concrete bridge girders. This website explains FHWA’s Exemplary Ecosystem Spliced girders were identified as the design option with Initiatives. The ecosystem approach looks at the present the greatest potential for extending span lengths. and beyond. It envisions future conditions under which ecological, economic, and social factors are integrated. http://trb.org/TRBNet/ProjectDisplay. The website contains details of the 43 initiatives that were asp?ProjectID=349 designated from 2002 through 2006. NCHRP Report 549, Simplified Shear Design of Structural Concrete Members, contains the findings of research http://azdot.gov/Highways/Privately_Funded_TI.asp performed to develop practical equations for design The Arizona Department of Transportation (ADOT) has of shear reinforcement in reinforced and prestressed established a handbook for the private development concrete bridge girders. Recommended specifications community as a uniform protocol for requesting new and commentary plus examples illustrating application of traffic interchanges (TI) or modifications to existing the specifications were also developed. The results of this interchanges. Links are provided to the Requirements research have been incorporated into the AASHTO LRFD Handbook and other ADOT Sections included in the Bridge Design Specifications. Privately Funded Traffic Interchange Process. http://trb.org/news/blurb_detail.asp?id=7443 Bridge Technology NCHRP Report 579, Application of LRFD Bridge Design Specifications to High-Strength Structural Concrete: Shear www.aspirebridge.org Provisions, examines research performed to extend the Previous issues of ASPIRE™ are available as pdf files and applicability of shear design provisions for reinforced may be downloaded as a full issue or individual articles. and prestressed concrete structures in the AASHTO LRFD Information is available about subscriptions, advertising, Bridge Design Specifications to concrete compressive and sponsors. You may also complete a reader survey to strengths greater than 10 ksi. provide us with your impressions about ASPIRE. It takes less than 5 minutes to complete. http://trb.org/news/blurb_detail.asp?id=8375 NCHRP Report 595, Application of the LRFD Bridge www.nationalconcretebridge.org Design Specifications to High-Strength Structural The National Concrete Bridge Council (NCBC) website Concrete: Flexural and Compression Provisions, explores provides information to promote quality in concrete bridge recommended revisions to the AASHTO LRFD Bridge construction as well as links to the publications of its Design Specifications to extend the applicability of the members. flexural and compression provisions for reinforced and www.hpcbridgeviews.org prestressed concrete to concrete compressive strengths This website contains 48 issues of HPC Bridge Views, a greater than 10 ksi. newsletter published jointly by the FHWA and the NCBC to provide relevant, reliable information on all aspects of high performance concrete in bridges.

52 | ASPIRE, Spring 2008 S A F E T Y AND S E R V I C E A B I L I T Y

Stiffer Bridges Result in Slower Bridge Deck DETERIORATION by James M. Barker

For many years, bridge design engineers have of the relationship of girder stiffness and deck In the NYSDOT work, the cracking of the been discussing and debating the benefits of cracking in the longitudinal direction parallel to bridge deck was found to be related to the stiff bridge superstructures. The issue involves the support girders. There seems to be a similar dynamic deflection component exhibited as the use of stiffer longitudinal girders relative to correspondence in the transverse direction as bridge superstructures vibrate during the passage the cracking of bridge decks. The presence of in the longitudinal direction due to load of live loads. A person standing on a bridge cracks leads to accelerated deterioration caused differentials and deformations associated with during the passage of a loaded concrete truck by reinforcement corrosion from water and the transverse distribution of wheel loads. or semi-trailer can certainly feel the difference corrosive salts entering the cracks. A number of in vibrations that occur on a stiff bridge versus studies and research reports have been completed Transverse Cracks due to those occurring on a flexible bridge. The since the early 1990s. This article provides an Longitudinal Loads resulting oscillations can also be felt after the update on some of the more recent studies. Investigations have delivered a substantial passage of the loads. The New York authors The majority of this discussion is related to amount of evidence that stiffer bridges exhibit less make the following statement: “In time, such a transverse cracks in bridge decks mostly near pier transverse cracking of bridge decks even where we phenomenon can cause cracking or make the locations on continuous bridges. These cracks expect to find those cracks. The work by Johnson is existing cracks, especially any transverse cracks, do not surprise any design engineer because, one of the latest studies that confirms this thinking. deeper and wider.” after all, the design theories assume that the Several states have invested in the belief that The NYSDOT report includes the following in slab is cracked when computing the areas of stiff bridges are longer-lasting bridges by the their conclusions: reinforcement required to carry the design loads. establishment of policies making every bridge Vibration severity is the most significant Transverse cracks are also possible in deck composite with the longitudinal support parameter influencing bridge deck cracking. longitudinal positive moment areas near girders no matter what material is used to Higher severity equates to higher deck cracking. midspans of bridges. This can be particularly fabricate the girders. Some states have even Decks with noticeable vibration cracked most true for older bridges where short end spans adopted a policy that composite action with the severely. may be continuous with longer second and use of shear studs or extended reinforcement Longer spans exhibit more deck cracking than third spans. These cracks can be caused by stirrups should be carried across the supports shorter spans. permit loads or overloads, which may exceed of continuous structures as well as in positive Bridges with noticeable vibration combined the slab compression caused by the dead loads moment midspan regions. While most designers with longer span lengths exhibited significant and provide sufficient tension to transversely still assume the top slab is cracked over the pier bridge deck cracking. crack the slabs. There is not usually sufficient supports, they do include the reinforcement in the NCHRP Report 297 reported on tests in the residual compression in the slab due to dead moment of inertia computations thus resulting in United Kingdom that showed that the most load to cause the cracks to close afterwards. a stiffer bridge in the longitudinal direction. influential factor on the risk of cracking caused Rational thinking indicates that a stiffer by traffic-induced dynamic deflection reversals heavier superstructure would result in larger Deck Slab Cracks and Vibrations is the amplitude of the deflection, not the dead load stresses and thus reduce the creation The New York State Department of frequency. The maximum dynamic deflection of transverse slab cracks in positive moment Transportation (NYSDOT) study titled “A generally increased as the maximum static areas of the bridge spans due to overloads. The Qualitative Study of Correlations between deflection increased. Portland Cement Association (PCA) Report SN Bridge Vibration and Bridge Deck Cracking” Thus it seems that vibrations can play a very 2936 titled “Effect of Superstructure Properties by Sreenivas Alampalli, et al. and published at the important role in bridge deck cracking. Stiffer on Concrete Bridge Deck Deterioration” by TRB Annual Meeting, Washington, D.C., 2002, was bridges vibrate to smaller deflection amplitudes Sanya Mackela Johnson, includes a discussion also summarized by Johnson in the PCA report. and exhibit less deck cracking.

ASPIRE, Spring 2008 | 53 FHWA

FHWA’S “GREEN” INITIATIVES

by M. Myint Lwin

SUSTAINABILITY IS... n the Winter 2008 Edition of ASPIRE,™ we The FHWA is committed to protecting and Recycled Materials Iread many exciting articles about projects preserving the environment through stewardship in Highway Construction and the application of sustainability concepts in and timely reviews. In recent years, the FHWA and The FHWA promotes and supports the use the planning, design, construction, operation, its partners have made substantial contributions of recycled materials in highway construction. and preservation of highway bridges. The FHWA to the environment and to the communities, Through the Recycled Materials Resource Center realizes the importance of developing and through planning and programs that support at the Universitys of New Hampshire, the FHWA is implementing sustainable solutions through wetland banking, habitat restoration, historic making changes in the extent of use of several working together at the federal, state, and local preservation, air quality improvements, bicycle industrial by-product materials in highway levels. Communities, industry, academia, and and pedestrian facilities, context-sensitive construction. The FHWA also has an active many others are in the chain of sustainable solutions, wildlife crossings, public and tribal Recycling Team that works with the states, the solutions for a sustainable future. government involvement, and others. Environmental Protection Agency, and industry In this issue of ASPIRE, we continue to read The FHWA is working closely with partners to to implement recycling technology. about sustainability and learn about ideas and take proactive measures in moving from simply SAFETEA-LU directs the reuse of debris from practices in applying the concepts of “Green mitigating environmental impacts to actively bridge demolitions in shore erosion control or Highways/Bridges” to enhance the natural and contributing to environmental enhancements. stabilization, ecosystem restoration, and marine built environment. habitat creation. Technology Deployment Programs Protecting and The FHWA’s technology deployment programs FHWA Exemplary Preserving the promote initiatives with social, economical, and Ecosystem Initiatives Environment ecological benefits, including: In 2002, the FHWA identified ecosystem In 2006, the • Use of high performance materials conservation as one of three performance FHWA published in pavement and bridge construction to objectives under the Agency’s “Vital Few” goal of an environmental increase durability, minimize maintenance, Environmental Streamlining and Stewardship. guide titled and reduce cost; To demonstrate its commitment to this goal, “Eco-Logical: • Use of prefabricated systems in pavement and the FHWA agreed to identify a minimum of 30 An Ecosystem bridge construction to accelerate construction, exemplary ecosystem initiatives in at least 20 Approach to improve work-zone safety, and reduce states or Federal Lands Highway Divisions by Developing disruption to the public. Fabrication of the September 2007. Infrastructure systems is done in controlled environments FHWA developed the following specific criteria Projects” to help improve the on or off the jobsite, resulting in improved for selecting the exemplary ecosystem initiatives: understanding of how infrastructure impacts quality and less impact on the environment; 1. An exemplary ecosystem initiative helps habitat and ecosystems. This multi-agency initiative • Use of self-propelled modular transporters sustain or restore natural systems and their describes a vision for integrating infrastructure (SPMT) in accelerated bridge construction functions and values. development and ecosystem conservation processes for removal and replacement of heavy 2. An exemplary ecosystem initiative is with economic, environmental, and social needs bridge components in record time; and developed within a landscape context. and objectives. An ecosystem approach is a method • Use of span-by-span, balanced cantilever, 3. An exemplary ecosystem initiative uses for sustaining or restoring ecological systems and and incremental launching techniques partnering and collaborative approaches to their functions and values. It is goal driven and in bridge construction to protect the advance common goals. is based on a collaboratively developed vision of environment by minimizing the needs for 4. An exemplary ecosystem initiative uses the desired future conditions that integrate ecological, construction equipment or work on the best available science in ecosystem and economic, and social factors. ground or wetlands below the bridges. habitat conservation.

54 | ASPIRE, Spring 2008 5. An exemplary ecosystem initiative provides clear examples of innovative environmental solutions by transportation agencies and achieves high standards in the environmental process. 6. An exemplary ecosystem initiative achieves high-quality results. 7. An exemplary ecosystem initiative is recognized by environmental interests as being particularly valuable or noteworthy. As of 2006, the FHWA had identified more than 40 exemplary ecosystem initiatives in over 30 states. More exemplary ecosystem initiatives are expected to be designated in 2007 and beyond. Examples of these initiatives are described below. See Concrete Connections on page 52 for the website with the locations and details of these initiatives. California—South Bay Expressway Mitigation Program The South Bay Expressway, State Route 125 South in San Diego County, is a 10.8-mile-long alignment that crosses through sensitive habitat for threatened and endangered species, known historic and cultural sites, community park areas, and established residential communities. The $20-million mitigation program includes everything from restoring habitat, mitigating Il 29 – Oak and hickory woodland on right. Floodplain forest wetland on left. Photo: IDOT. noise and air pollution, protecting water quality, and recovering cultural resource data. Illinois—Route 29 Improvements to of National Resources (IDNR), U.S. Army Corps • Sp lit Interchange Design. IDOT Protect Ecosystems of Engineers, U.S. Environmental Protection uses a “split interchange” design for a new This is a 35-mile-long corridor that runs from Agency, U.S. Department of the Interior, and the Route 27-Route 29 interchange within the State Route 6 near Mossville in Peoria County FHWA to develop minimization and mitigation village of Sparland. A “split interchange” to I-180 in Bureau County. The highway lies strategies, such as: design divides an interchange in half. Half between bluffs and blufftop farmlands to the • Sp lit Profile Roadway. Three miles of the interchange will be located at the west and the Illinois River to the east. Two-lane of Route 29 have been designed as a southern end of Sparland, and the other Route 29 is being studied for expansion to four “split profile” roadway, meaning that the half at the northern end. Separating the lanes. The Illinois Department of Transportation southbound lanes will be 3 to 17 ft higher ramps by nearly a mile is expected to reduce (IDOT) partnered with the Illinois Department than the northbound lanes, avoiding impacts to Sparland, nearby wetlands, an impacts to upland forests and natural areas IDNR property, flood-buyout properties, and along the bluff; residential areas; and • Wildlife Passages. IDOT proposes about 30 wildlife passages for mammal and amphibian/reptiles roadkill hot spots. The passages are predicted to reduce the high number of animal-vehicle collisions and improve wildlife movement. Additionally, bridge spans will be lengthened to provide a sufficiently wide, dry-crossing area for large animals.

Rendering depicts a “split Profile” roadway. Rendering: CH2M Hill.

ASPIRE, Spring 2008 | 55 fostering ecosystem-based studies and solutions in The New Hampshire Department of Transportation created a 320-acre Pine working closely with partners, stakeholders, and the Road Wetlands Mitigation Site. communities. Photos: Normandeau Associates Inc. Closing Remarks New Hampshire—Route 101 Ecological in working together with the Cascades Conservation SAFETEA-LU, Section 6002 Efficient Environ- Protection and Enhancement Feature Partnership, the Alpine Lakes Protection Society, the mental Reviews for Project Decisionmaking, has This initiative showcases a multi-faceted Mountains-to-Sound Greenway, and the Kongsberger integrated environmental planning factors into mitigation plan to improve 17.6 miles of Route 101 Ski Club to provide ecological solutions to the I-90 statewide and metropolitan planning processes by from Epping to Hampton. The governor of New improvements. Some of the solutions are requiring that transportation agencies coordinate Hampshire appointed a Task Force to address the • Wildlife Distribution. U.S. Forest with resource agencies and public stakeholders concerns of local residents on the potential impact Service researchers used geographic information as early as possible in the environmental review on their homes, businesses, and historic properties, systems technology, snow-tracking, and other process. These efforts are expected to lead to more and the desire of the environmentalists to avoid techniques to learn the movements of animals informed decision-making in transportation impacts on local wetlands and other wildlife habitat. to understand wildlife distribution along and planning; proactive integration of natural resource The Task Force guided the project development near the highway; considerations with transportation needs; and to a mitigation strategy that focused on a broad • Connectivity Bridges. A working identification and prioritization of opportunities “landscape approach” to fit the local ecosystem and group of biologists and hydrologists identified with the greatest potential to mitigate the possibly resource management needs. Some of the ecosystem where and how connectivity bridges should harmful environmental impacts of proposed solutions are: be built along I-90. The connectivity bridges transportation projects. • Outdoor Laboratory. The New should provide wide and open space for large The FHWA has been and continues to be a Hampshire Department of Transportation mammals to cross; and leading partner in the Green Highways Partnership created a 320-acre Pine Road Wetlands • Stream Crossings. The working group (GHP), which is a voluntary, public/private initiative Mitigation Site. Students from high schools recommended that bridges be built primarily at dedicated to the innovative concepts and approaches and colleges use this wetland site to study water stream crossings, since they represent locations to “Green Transportation Infrastructure” through quality and other wetland functions; where multiple project and ecosystem needs community partnering, environmental stewardship, • Replacing Culverts with Bridges. converge and therefore offer an opportunity and transportation network improvements in Existing culverts on the Piscassic River were for synergistic solutions. The stream-crossing safety and functionality. The FHWA has contributed replaced by a twin-span bridge to provide bridges should be designed to accommodate significant resources towards the partnership, improved hydraulic performance and a better aquatic, riparian, and terrestrial habitat including staff time, monetary commitments, corridor for wildlife movements across the features. The crossings should be expansive and technological expertise. The environment highway; and enough for large mammals to utilize and built is everybody’s concern, and at FHWA, it assumes • Lengthening a Bridge. A bridge over at key linkages of major creeks and wetlands. a particular importance—one that touches the Squamscott River was lengthened by 560 ft virtually every aspect of highway planning, design, to restore 4 acres of salt marsh. construction, and preservation. Washington—I-90 Snoqualmie Pass In the next two issues of ASPIRE, we will East Project continue to explore the social, economic, and Interstate 90 is the main east-west route across ecological benefits of sustainability in planning, the Cascades into Seattle. The Snoqualmie Pass—a design, construction, preservation, and renewal 15-mile-long section of the highway—is infamous of the highway infrastructure. I invite readers to for its avalanche hazards, its dangerous curves, its share ideas and suggestions, facts and figures, deteriorating pavement, and increasing traffic. The Washington—I-90 Snoqualmie Pass East Project, case studies, and photographs on these topics by project crosses a critical north-south corridor for stream crossing. Photo: WSDOT. writing to me at [email protected]. elk, lynx, gray wolf, grizzly bear, and wolverine. The project also cuts through areas of habitat The common threads in the exemplary ecosystem connecting much larger habitat areas along the initiatives are reducing habitat fragmentation, mountain range. The Washington State Department removing barriers to animal movement, encouraging of Transportation (WSDOT) partnered with the U.S. the development of more sustainable mitigation U.S. Department of Transportation Forest Service, state, and federal resource agencies sites, stimulating early ecosystem planning, and Federal Highway Administration

56 | ASPIRE, Spring 2008 Silica Fume Association The Silica Fume Association (SFA), a not-for-profit corporation based in Delaware, with offices in Virginia and Ohio, was formed in 1998 to assist the producers of silica fume in promoting its usage in concrete. Silica fume, a by-product of silicon and ferro-silicon metal production, is a highly-reactive pozzolan and a key ingredient in high performance concrete, dramatically increasing the service-life of structures. The SFA advances the use of silica fume in the nation’s concrete infrastructure and works to increase the awareness and understanding of silica fume concrete in the private civil engineering sector, among state transportation officials and in the academic community. The SFA’s goals are two-fold: to provide a legacy of durable concrete structures and to decrease silica fume volume in the national waste stream. Some of the recent projects completed by the SFA, under a cooperative agreement with the Federal Highway Administration (FHWA), include: • The publication of a Silica Fume User’s Manual—the manual is a comprehensive guide for specifiers, ready mixed and precast concrete producers, and contractors that describes the best practice for the successful use of silica fume in the production of high performance concrete (HPC). • The introduction of a Standard Reference Material (SRM)® 2696 Silica Fume for checking the accuracy of existing laboratory practices and to provide a tool for instrument calibration. This SRM is available from the National Institute of Standards and Technology (NIST). A much anticipated research program nearing completion by the SFA is the testing of in-place silica fume concrete under service conditions. At the conclusion of this research the results will demonstrate the benefit of silica fume concrete’s unparalleled long-term performance. For more information about SFA, visit www.silicafume.org.

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10857_Carolina_Stalite_Company_fall07.indd 1 8/23/07 10:00:30 AM ASPIRE, Spring 2008 | 57 STATE

Concrete Bridges in

Arizona by Jean A. Nehme and Tina Sisley, Arizona Department of Transportation

the original construction of I-10 and I-17 in the Phoenix and Tucson areas. For economical reasons, similar span and girder arrangements were used as frequently as possible. Voided

Early bridge over I-17, Central Phoenix. (Two-span prestressed concrete I-girders). Loop 202 over Indian Bend Wash, Tempe. (Seven-span prestressed concrete I-girders). All photos: Arizona Department of Transportation. slabs and box beams with asphaltic concrete overlays were used on the I-40 and various state istorically, concrete has been the material that can span longer distances, thus eliminating highways. Construction plans for these girders Hof choice for bridge construction in costly substructure units and providing plausible often allowed the contractor a choice between Arizona. Raw materials needed to produce solutions to complex bridge sites. prestressing methods: either pretensioned concrete are readily available within the state. or post-tensioned. In most instances, as-built Prestressed I-girder and post-tensioned box Historical Overview drawings did not document which method was girder bridges have been the most commonly The use of precast concrete girders began in used. High profile vehicle collisions with such constructed bridge types on Arizona’s highways Arizona in the late 1950s. Precast girders of girders, exposing ducts or strands, offered some for the past several decades, especially in urban various types can be found on all of Arizona’s clues to the mystery. settings. Examples of early precast I-girder interstate and state highway routes. The earlier bridges dating to the 1950s can still be found types of precast girders consisted of small Current Practice throughout the state. Over time, Arizona bridge I-girder shapes, voided slabs, and box beams. Today, the more commonly used precast construction has followed the industry trends The AASHTO Type II girder appears to be the girders are those that can span 90 to 135 ft, to use larger precast, prestressed I-girder shapes primary precast girder used in many bridges in such as the AASHTO Type IV, V, and VI girders.

Early bridge on I-10 over St Mary’s, Tucson. (Two-span prestressed concrete I-girders).

Loop 202 and Interstate 10 Interchange, Chandler. (Post-tensioned box girders).

58 | ASPIRE, Spring 2008 Arizona uses modified versions of the Type V and VI for most bridges. The modified girder type has flange and web widths that are 2 in. narrower than the regular type to reduce the amount of dead load transferred to the substructure. Type II and III girders are no longer being used on new bridge construction due to their span limitations. Their use has declined so much that Arizona fabricators no longer have the formwork to make them. Recently, a contractor replacing a Type II girder damaged by a high vehicle collision had to use an Idaho supplier. Phoenix metropolitan area. (Relief on exterior girder).

Expansion of the Urban experiencing increased demand for longer spans, Freeway System shorter construction durations, and reduction in During the last two decades, the Arizona construction-caused traffic delays. Use of precast Department of Transportation (ADOT) has member elements for bridge construction in been faced with the challenge of expanding the other than the superstructure such as in column freeway system to accommodate the increased cap beams and abutments could solve some volume of traffic generated by the growing of these issues. Precast, prestressed concrete Damage assessment at Tangerine over I-10, Tucson. urban metropolises of Phoenix and Tucson. This is versatile, durable, and enables shorter (Two-span prestressed concrete I-girders). expansion is being accomplished by widening construction durations. existing freeways and the construction of Due to a recent increase in development Another modified girder type used in the past additional freeways. throughout Arizona, bridges are being proposed and in several recent projects is what we term a In the heart of Phoenix on I-17, ADOT has and funded by private developers. In order to Super Type VI girder. The depth of the AASHTO replaced many of the first generation AASHTO streamline this process, ADOT has developed an Type VI girder is increased by 6 in. The Super Type II girder bridges, which carry local streets on-line manual. (See Concrete Connections Type VI girder was first used on the mile long over the interstate, with shallower precast, on page 52 for website address.) This includes Salt River Bridge carrying the Loop 202 freeway prestressed adjacent box beam bridges to a typical footprint for urban traffic interchange within the city of Tempe. The eastbound and accommodate longer spans and to improve bridges that incorporates future widening westbound bridges consist of 34 spans with one vertical clearances over the interstate. criteria for both the highway and the cross street. span of Type V girders, eight spans of standard In the Tucson area, I-10 is currently being This footprint consists of a two-span bridge with Type VI girders and 23 spans of the Super Type widened. Many of the bridges use AASHTO Type span lengths of 135 ft, which could be achieved VI girders. II girders and are being widened in kind with through the use of AASHTO Type VI girders. Type II girders shipped from out of state. Longer spans would be required in case of a skew to the bridge. Future Outlook and In the Phoenix metro area, many of the Challenges freeways that were built within the last two Aesthetics considerations are becoming decades are already being widened. In many increasingly important in the construction of cases, these freeways were originally constructed transportation facilities. Bridges constitute some prior to the land being developed around them. Loop 202 over Alma School, Mesa. (Two-span of the most visible elements of the transportation This afforded us the luxury of building on new prestressed concrete I-girders). infrastructure. Precast, prestressed concrete alignments without being concerned about traffic bridge elements can be constructed with reliefs control. Common bridge types were cast-in-place Collision Damage on the exterior girder or box elevations to post-tensioned box girders. However, widening The strength and resilience of precast concrete enhance the visual appearance of the structure. of these existing roadways is presenting many girders have been tested on many occasions ADOT has implemented these methods on many challenges. We are faced with a wide range of when girders have been damaged by over-height urban projects. issues, which include minimizing traffic impacts vehicles. In most cases, the damaged girders We also realize that new shapes and some during construction, constructing over traffic, have been easily repaired with epoxy injection innovative bridge design ideas will have to maintaining minimum vertical clearances, site and high strength grout patching. Only in few be implemented in order to meet some of the restrictions due to tight right-of-way, various instances were the whole girders replaced. future challenges that we are facing. We are environmental issues, and multiple requests

ASPIRE, Spring 2008 | 59 Wild Horse Pass over I-10, south of Phoenix. (Two-span prestressed concrete I-girders).

Aesthetically Pleasing Solution with Minimal from the public and the affected municipalities. beingImpact considered. While the tub and trapezoidal Nowadays, Arizona bridge designers are box beam girder shapes have been used in other looking at new solutions to conquer these states, they have not been developed in Arizona challenges. A current project involving the partly due to the startup cost involved with their widening of 10 miles of urban freeway, including development. 20 post-tensioned box girder bridges and ______three precast AASHTO girder bridges, is under Jean A. Nehme is State Bridge Engineer and Tina development. Four of the box girder bridges Sisley is Bridge Design Leader with the Arizona Department of Transportation. span over single point interchanges, one with a Camelback over I-17, central Phoenix. single span of 250 ft. A combination of precast, (Two-span prestressed concrete I-girders). prestressed girders; precast, post-tensioned spliced For more information on Arizona’s bridges, girders; and several new precast shapes such visit www.azdot.gov/highways/bridge/ as tub girders and trapezoidal box beams are index.asp.

Environmental Constraints

Arizona highways traverse a variety of terrains including flat desert, falsework construction in washes prone to unpredictable flooding, and rolling hills, and deep canyons. Environmental concerns such as reduced the construction time. This project won the ARTBA 2006 Globe minimizing the impact to unique or impaired waterways, minimizing Award for Environmental Excellence. disturbances of sensitive sites, and avoiding archeological features create many construction challenges. Precast concrete elements can minimize the footprint of the bridge. For waterway crossings, precast members eliminate the need for falsework during construction. This reduces the environmental impacts and minimizes the risk posed by flash floods. A recent project to construct a 7.5-mile-long segment of the new Route 188 connecting the city of Globe with the Roosevelt Lake recreational area northeast of Phoenix contained six precast concrete girder bridges. Some bridges were needed to provide wide open areas beneath the roadway for wildlife crossings within the Tonto National Forest and others were built to span waterways. Precast girder types ranging from AASHTO Type IV to Type VI provided the means to span the varying terrain of the new roadway alignment. The use of precast, prestressed State Route 188 over Apprentice Wash, Gila County. concrete girders minimized site disturbance, eliminated the need for (Three-span prestressed concrete I-girders).

60 | ASPIRE, Spring 2008 Expanded Shale, Clay, and Slate Institute The Expanded Shale, Clay & Slate Institute (ESCSI) is the international trade association for manufacturers of expanded shale, clay, and slate (ESCS) aggregates produced using a rotary kiln. The institute is proud to sponsor ASPIRE™ magazine. Lightweight aggregate concrete has been used successfully in the rehabilitation of many bridges, including such well known bridges as the Brooklyn Bridge (N.Y.), the San Francisco-Oakland Bay Bridge (Calif.), the Woodrow Wilson Bridge (D.C.), the Louis and Clark Bridge (Wash. and Ore.), the Whitehurst Freeway (D.C.), the Chesapeake Bay Bridges (Md.), the Cape Cod Canal Bridges (Mass.), and the Coleman Bridge (Va.). Using lightweight concrete for bridge rehabilitation can provide the following benefits: • Wider decks with little or no modification of the existing structure; • Reduced deck weight to improve the load rating on an existing structure; • Reduced weight of precast elements for hauling and installation; and • Enhanced durability. For more information on lightweight concrete, including a listing of ESCSI members and available publications, please visit www.escsi.org. The members of ESCSI look forward to assisting owners, designers, and concrete producers in using lightweight concrete for bridges.

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ASPIRE, Spring 2008 | 61 COUNTY Annual bridge projects are fairly standard, except for occasional standouts

Accelerated Bridge Thinking BIG in Boone Construction

County, Iowa by Robert Kieffer, Boone County, Iowa Not all of the county’s bridges utilize standard designs. In 2006, the county worked with the Bridge Engineering oone County typically constructs one The changes are particularly significant for Center at Iowa State University in nearby Bbridge per year based on needs developed bridges over water, because the slab bridges Ames and the Iowa Department of from our master map, which breaks down require less clearance than concrete beam Transportation to determine the feasibility structures by posted weights, number of lanes, bridges. Raising a slab bridge so it is above of using precast concrete components traffic flow, and other factors. Our key challenge the design high-water elevation requires less to accelerate bridge construction. is that, as a rural county, we have a variety earth work and material costs, which creates Through the Federal Highway of roads that aren’t paved, which are used by savings—and savings are critical when funding Administration Innovative Bridge farmers with heavy equipment. We also have the is restricted. Research and Construction Program, Des Moines River running through the county, Occasionally we have special projects such 120th Street Bridge over Squaw Creek which requires more complex bridge designs as a 700-ft-long, five-span precast, prestressed was constructed using several different compared to a structure over a creek or stream. concrete beam bridge across the Des Moines precast, high-performance concrete Most of the projects that we build consist of River. This structure was constructed with beams elements. The result was a 152-ft-long, reinforced concrete slabs or precast, prestressed ranging in span length from 130 to 140 ft that three-span bridge featuring precast concrete beams with a cast-in-place concrete were specially designed for the project. concrete abutment footings, precast pier deck. We’re in a pretty good area for doing These unusual projects teach us a great deal caps, and precast full-depth transversely those types of designs, with a number of bridge about using materials to their fullest. That, pretensioned and longitudinally post- contractors and high-quality precasters within in turn, helps us to design the more standard tensioned, 8-in.-thick deck panels. a 100-mile distance of our county. Concrete is bridges that we deal with every year. Standard 32-in.-deep precast, prestressed an excellent material to work with, because it concrete I-beams were used, with four requires virtually no maintenance over the years. ______(rather than the standard five) beams per Robert Kieffer is County Engineer, Boone County, span. The Mackey Bridge won the award We typically use standard Iowa Department Iowa. of Transportation bridge designs. We are pleased as Best Owner-Designed Bridge in the that the designs are being updated to provide Precast/Prestressed Concrete Institute’s more flexibility and reflect concrete’s versatility. Design Awards Competition for 2007. For instance, concrete slab beams previously Information learned from the project could be extended up to span lengths of 125 about designing completely with ft, but that has been now lengthened to 150 precast concrete elements will benefit ft. Designs used to be divided into 12.5-ft-span future projects especially in the areas of length increments, but now they are provided scheduling and staging. We believe that in 10-ft increments. The changes provide more another such design would move even options and help us create greater span lengths. faster due to the steep learning curve we experienced.

The Mackey Bridge in Boone, Iowa, was designed with precast concrete components as a feasibility project to determine how construction could be accelerated. Photos: Iowa DOT. Editor’s Note

If your county has a high percentage of concrete bridges or some interesting and innovative concrete bridges and would like to be featured in ASPIRE™, please let us know at [email protected]. National Ready Mixed Concrete Association The National Ready Mixed Concrete Association is A product expo featuring companies that offer products sponsoring the Third Annual Concrete Technology Forum: and services for sustainable development will be open during Focus on Sustainable Development. The symposium will bring the conference. Attendees will earn valuable professional researchers and practitioners together to discuss the latest development hours (PDHs) and will receive a copy of the advances, technical knowledge, continuing research, tools, conference proceedings. and solutions for concrete and sustainable development. NRMCA, based in Silver Spring, Md., represents the Over 50 technical sessions on state-of-the-art developments, producers of ready mixed concrete and the companies that new construction techniques, and product formulations that provide materials, equipment, and support to the industry. It optimize environmental performance of concrete construction conducts education, training, promotion, research, engi- will be presented including: neering, safety, environmental, technological, lobbying, and • Pervious Concrete Systems; regulatory programs. • Concrete’s Impact on Urban Heat Islands; National Ready Mixed Concrete Association, 900 Spring Street, Silver Spring, MD 20910, 888-84NRMCA (846-7622), • The Carbon Footprint of Concrete; www.nrmca.org. • Sustainable Development Initiatives; and • Optimizing Recycled Content.

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Aspire.indd 1 2/13/08 9:54:45 AM ASPIRE, Spring 2008 | 63 AASHTO LRFD

Safety and the

LRFD Specifications by Dr. Dennis R. Mertz

ith the collapse of the I-35W Bridge in the data required to determine safety, and if so, behavior, the inherent probability of failure of WMinneapolis, bridge safety is a timely how safe is safe? LRFD designs is lower than 2 in 10,000. subject of discussion. A review of the level of To develop an LRFD-format specification, The final question with regard to safety and safety inherent in our patrimony of highway exemplified by Equation 2, where a deterministic the LRFD Specifications is, why 2 in 10,000 bridges is in order. approach is made probabilistic through the as a target failure rate? This question was For over 50 years, beginning with the AASHTO application of carefully chosen load and resistance answered during the development of the first Standard Specifications for Highway Bridges, factors, a target level of safety is necessary to define edition of the LRFD Specifications. A sample of Allowable Stress Design (ASD) was the design the values in the LRFD equation: bridges designed using the LFD methodology methodology employed. The ASD methodology of the Standard Specifications was analyzed

uses a factor of safety (FS) as a multiplier on ∑γi Qi ≤ φRn (2) probabilistically to ascertain their inherent load to set the required resistance as shown in i probability of member failure. The approximate Equation 1: where γ and φ represent carefully selected average failure rate associated with bridges load and resistance factors to achieve a target designed using LFD was about 2 in 10,000. R ≥ (FS) × Q (1) level of safety. Structural reliability provides the Thus, this member failure rate was chosen as tools to select the factors’ required values to the target for the calibration of the load and where R is the resistance and Q is the load reach a target level of safety. But, what level of resistance factors of the LRFD Specifications. or force effect. The factor of safety varies for safety? Safety against failure of a member, such Some existing bridges (short span bridges) different loads and materials. The factors of as can easily be produced in a laboratory, or appear to have inherent member failure rates as safety were chosen subjectively by the code safety against failure of the entire bridge system? high as 6 in 100 (β = 1.5), yet these bridges are writers, but history proved that highway bridges Much data exist for the resistance of individual not considered unsafe. For load rating, bridges designed to ASD are inherently safe. The question members at failure (in the terminology of LRFD; are rated at the operating level in the Load and is, how safe? the nominal resistance); little data exist for Resistance Factor Rating (LRFR) methodology at With the introduction of Load Factor Design failures of whole bridges. The calibration of the a failure rate of 6 in 1,000 (β = 2.5). (LFD) in the 1960s, the varying uncertainties of LRFD Specifications is based upon member All of the member failure rates used to calibrate different load components were acknowledged. resistance, but individual members do not fail our current design and rating specifications are The design equation is similar to the LRFD in a true system. Consider a multi-girder bridge: based upon comparisons with past practice—a equation but with load and resistance factors as one girder softens due to approaching ductile practice based upon subjectively chosen factors chosen through comparison with bridges failure, and a sufficient load path to the adjacent of safety. Our bridges have proven safe over the designed using ASD. Again, the level of safety girders exists (and the concrete deck can be such last 75 years of the AASHTO specifications, but is unknown, but bridges apparently are safe a load path), the load redistributes to the other the question remains, how safe is safe enough? enough as failures are very few. girders from the softening girder. Before, the With the LRFD Specifications, our nation’s new During the late 1970s, the theory of structural complete ductile failure of the one girder, the bridges have become reliability evolved into a useable highway bridge other girders begin to help carry the load shed more uniformly safe design methodology with the development of the from it. Thus, the target level of safety inherent in terms of member Ontario Highway Bridge Design Code. AASHTO in the LRFD Specifications with a probability of failure and extremely followed in the late 1980s with the development failure of 2 in 10,000 (where the reliability index safe in terms of of the LRFD Bridge Design Specifications, β = 3.5) for member failure (introduced in this system failure, but eventually published in 1994. For the first time, column in the Winter 2007 issue) is much lower the level of safety a rational quantification of safety was available. for whole system behavior for typical ductile is still relatively The questions now become: Do we have all of designs. So depending upon the degree of system subjective.

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ASPIRE, Spring 2008 | Web PUYALLUP RIVER Bridge / WASHINGTON