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T H E C O N C R E T E B R I D G E M A G A Z I N E

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.aspirebridge.org

F A L L 2 0 1 1

MON-FAYETTE EXPRESSWAY BRIDGEBrownsville, Pennsylvania

NORTHEAST 36TH STREET BRIDGE

OVER SR 520

Redmond, Washington

BIG BEAR BRIDGESan Bernardino Mountains at Big Bear Lake,

California

DULLES CORRIDOR METRORAIL

PROJECT AERIAL GUIDEWAYSTysons Corner, Virginia

I-80 BRIDGES OVER ECHO DAM ROADEcho, Utah

THE COVERED BRIDGE OVER THE

KENNEBEC RIVERNorridgewock, Maine

SANTA URSULA CONNECTORLaredo, Texas

SW Line Flyover Bridge,Nalley Valley Interchange

Tacoma, Washington


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Beijing Wowjoint Machinery Co. . . . . . . . 41

Bentley Systems Inc. . . . . . . . . . . . . . . . . . . 3

CABA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Dywidag-Systems International USA . . . . 3

FIGG . . . . . . . . . . . . . . . . . Inside Front CoverFlatiron . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Hamilton Form Company . . . . . . . . . . . . . 17

Headwaters Resources . . . . . . . . . . . . . . . . . 6

LARSA USA . . . . . . . . . . . . . . . . . . . . . . . . . 21

Meadow Burke . . . . . . . . . . . . . . . . . . . . . . 51

Mi-Jack Products . . . . . . . . . . . . . . . . . . . . 49PB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

PCI . . . . . . . . . . . . . . . . . . . . . . . . 7,29, 45,53

Poseidon Barge . . . . . . . . . . . . . . Back Cover

Reinforced Earth . . . . . . . . . . . . . . . . . . . . 13

T.Y. Lin International . . . . Inside Back Cover

Advertisers Index

ASPIRE, Fall 2011|1

C O N T E N T S

Photo: California Department of Transportation.

Photo:McNaryBergeron&AssociatesInc.

Photo: McNary Bergeron & Associates Inc.

Photo: Kleinfelder..

FeaturesMcNary Bergeron & Associates 8Construction-engineering work helps ensure efficient andcost-effective construction.

Mon-Fayette Expressway Bridge 14Value-engineering creates a tall, elegant concrete segmental

design for the Pennsylvania Turnpike.Northeast 36th Street Bridge over SR 520 18Creating a level playing fielda bridge and a park builtover busy freeway.

Big Bear Bridge 22A time to replaceconstructing a safer tomorrow.

Dulles Corridor Metrorail Project AerialGuideways 26Connecting the nations capital with its international airport.

I-80 Bridges over Echo Dam Road 30A sliding scale.

The Covered Bridge over the Kennebec River 34Re-creating history: modern techniques preserve character ofhistoric bridge.

Santa Ursula Connector 38

DepartmentsEditorial 2

Concrete Calendar 4

Reader Response 6

CCCARC Wildlife Crossing 12

Aesthetics Commentary 37

FHWAThe Office of Federal Lands Highway 42

Safety and Serviceability 44

STATENew York State 46

COUNTYKing County, Washington 50

Concrete Connections 52

Buyers Guide 54

AASHTO LRFDThe Fatigue Limit States, Part 2 56

8

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4/602|ASPIRE, Fall 2011

EDITORIALExecutive EditorJohn S. Dick

Managing Technical EditorDr. Henry G. Russell

Managing EditorCraig A. Shutt

Editorial AdministrationJames O. Ahtes Inc.

Art DirectorPaul Grigonis

Layout DesignTressa A. Park

Ad SalesJim Oestmann

Phone: (847) 838-0500 Cell: (847) 924-5497Fax: (847) 838-0555

[email protected]

Reprint SalesPaul Grigonis

(312) 360-3217e-mail: [email protected]

PublisherPrecast/Prestressed Concrete Institute

James G. Toscas, President

Editorial Advisory BoardWilliam N. Nickas,Precast/Prestressed Concrete

Institute (PCI)

William R. Cox,American Segmental Bridge Institute

(ASBI)

Dr.David McDonald,Epoxy Interest Group (EIG)

Dr. Henry G. Russell,Henry G. Russell, Inc.

John S. Dick, J. Dick Precast Concrete Consultant LLCPOSTMASTERSend address changes toASPIRE

200 W. Adams St., Suite 2100Chicago, IL 60606.Standard postage paid at Chicago, IL, and additional

mailing offices.

ASPIRE (Vol. 5, No. 4),

ISSN1935-2093is published quarterlyby the Precast/Prestressed Concrete Institute

200 W. Adams St., Suite 2100Chicago, IL 60606.

Copyright 2011, Precast/Prestressed Concrete Institute.

If you have a project to be considered forASPIRE, send

information toASPIRE200 W. Adams St., Suite 2100Chicago, IL 60606phone: (312) 786-0300www.aspirebridge.org

e-mail: [email protected]

CoverSW Line Flyover Bridge, Nalley Valley Interchange,

Tacoma, Washington

Photo: Guy F. Atkinson Construction LLC.

Challenges, Engineers, and Solutions

Log on NOW atwww.aspirebridge.organd take theASPIREReader Survey.

As we review projects for potential use in

ASPIRE, the editorial team cant help

but be impressed with how engineers respond to the

challenges of envisioning and designing their bridges.

This extends to the contractors who execute the

designs and the agencies that approve and ultimately

accept them. The results are frequently awe-inspiring.

Size doesnt matter: miles of spans or just one,

short-spans or long-spans, two lanes or six lanes. We

see impressive solutions being used in most bridges

around the country these days. The projects described

in this issue are no exception.

The Mon-Fayet te Expressway Br idge in

Pennsylvania saved the owner $8.5 million with a

value-engineering proposal. Sitting on piers up to 200ft tall, the cast-in-place concrete box girder includes

a span of 518 ft. Low-permeability concrete and other

measures provide a life expectancy of 100 years. This

article begins onpage 14.

In Washington State, a unique lid over an

expressway connects both parts of a major office

complex. It not only provides a vehicular bridge but

carries the adjacent landscaping over the freeway with

pedestrian-friendly meandering walkways that blend

seamlessly into the surrounding environment. Readthe article beginning onpage 18.

Big Bear Bridge in California comprises a

474-ft-long arch supporting two 237-ft-long equalspans of post-tensioned, cast-in-place concrete box

girders. This striking bridge, located near the south

branch of the San Andreas Fault, is designed to resist

a significant seismic event in part with the use of two

6.5-ft-diameter friction pendulum isolation bearingsat the crest of the arch. This feature begins onpage 22.

The Dulles Metrorail Aerial Guideway project near

the nations capital is being constructed just feet away

from some of the countrys heaviest traffic. The first

phase of the project is 11.6 miles long, includes 3miles of aerial guideway, 3 aerial stations, and a

2400-ft-long tunnel. At its highest point, it is 55 ft over

the eight-lane I-495 Capital Beltway.(See page 26)The twin I-80 Bridges over Echo Dam Road in

Echo, Utah, were not built where you will find them

today. They were built off line, out of traffic, and

then slid into place in a matter of hours each. This

permitted the heavily-travelled interstate highway

to remain in service except for a brief closure of two

lanes. How they did it is explained beginning on page

30.

The Covered Bridge over the Kennebec River in

Norridgewock, Me., hasnt been covered in many

years. The story behind the challenge to create this

beautiful structure, only the second major concrete

tied arch bridge in the United States, is impressive.

The arch spans 300 ft and rises 60 ft above the deck.With a total length of 570-ft, the bridge has no deck

joints and incorporates measures that will provide a

100-year service life. The article starts onpage 34.

So far, the articles alternate between the east and

west coas ts. The fina l featured proj ect is in Texas.

The Santa Ursula Connector in Laredo needed to

be designed for the condition of being 25 ft belowhigh water level of the Rio Grande River. That

required a shallow superstructure and substantial

resistance to overturning. The selection of the Texasstandard 15-in.-deep, precast, prestressed concrete

solid slabs seemed logical. It provided a 22-in.-deepsuperstructure with a smooth soffit that wont trap

debris. But, it was on a sharp horizontal curve. How

the designers handled all of the constraints begins on

page 38.

Once again, we salute the innovative designers and

constructors who have met their challenges head-on.

They have provided bridges that not only satisfy the

unique site demands but create interesting stories

that we are pleased to share in ASPIRE. If you have

a project that you would like to have considered,

whether larg e or smal l, please contact us at www.aspirebridge.org and select Contact Us. We look

forward to hearing from you.

Photo: Ted Lacey Photography.

John S. Dick,Executive Editor

Epoxy Interest GroupPrecast/Prestressed Concrete Institute

Portland Cement AssociationExpanded Shale Clay and Slate InstituteSilica Fume Association

American Segmental Bridge Institute
mailto:[email protected]:[email protected]://www.aspirebridge.org/http://www.aspirebridge.org/http://www.aspirebridge.org/mailto:[email protected]://www.aspirebridge.org/http://www.aspirebridge.org/http://www.aspirebridge.org/http://www.aspirebridge.org/http://www.aspirebridge.org/http://www.epoxyinterestgroup.org/http://www.pci.org/http://www.cement.org/bridgeshttp://www.escsi.org/http://www.silicafume.org/http://www.asbi-assoc.org/http://www.cement.org/bridgeshttp://www.escsi.org/http://www.silicafume.org/http://www.epoxyinterestgroup.org/http://www.asbi-assoc.org/http://www.pci.org/http://www.aspirebridge.org/mailto:[email protected]://www.aspirebridge.org/mailto:[email protected]:[email protected]


5/60ASPIRE, Fall 2011|3
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6/604|ASPIRE, Fall 2011

CONCRETE CALENDAR 2011/2012CONTRIBUTING AUTHORS

MANAGINGTECHNICAL EDITOR

M. Myint Lwinis director

of the FHWA Office of Bridge

Technology in Washington, D.C.

He is responsible for the National

Highway Bridge Program

direction, policy, and guidance,

including bridge technology

development, deployment and

education, and the NationalBridge Inventory and Inspection

Standards.

Dr. Dennis R. Mertzis

professor of civil engineering

at the University of Delaware.

Formerly with Modjeski and

Masters Inc. when theLRFD

Specificationswere first written,

he has continued to be actively

involved in their development.

Frederick Gottemoeller

is an engineer and architect,

who specializes in the aesthetic

aspects of bridges and highways.

He is the author ofBridgescape,

a reference book on aesthetics

and was deputy administrator

of the Maryland State Highway

Administration.

Dr. Henry G. Russellis an

engineering consultant, who

has been involved with the

applications of concrete in

bridges for over 35 years and

has published many papers

on the applications of high-

performance concrete.

October 22-25, 2011PCI Annual Convention andExhibition and National BridgeConferenceSalt Lake City Marriott Downtown andSalt Palace Convention Center

Salt Lake City, Utah

October 31November 4, 2011National Bridge Management,Inspection, and PreservationConferenceMillennium Hotel DowntownSt. Louis, Mo.

November 1-3, 2011Concrete and Concrete RepairSchoolSponsored by the United StatesDepartment of InteriorBureau ofReclamationRegistration Deadline is October 14,2011. Limited to 30 participants.Denver Federal CenterDenver, Colo.

November 7-8, 2011ASBI 23rd Annual ConventionWashington Marriott Wardman ParkWashington, D.C.

November 14-19, 2011PCI Quality Control & AssuranceSchools, Levels I, II & IIIEmbassy Suites Nashville Airport HotelNashville, Tenn.

January 22-26, 201291st Annual MeetingTransportation Research BoardMarriott Wardman Park, OmniShoreham, and Hilton WashingtonWashington, D.C.

January 23-27, 2012World of Concrete 2012Las Vegas Convention CenterLas Vegas, Nev.

February 16-18, 20124th International Conference onGrouting and Deep MixingSponsored by the InternationalConference Organization for Groutingand the Deep Foundations Institute

Marriott New OrleansNew Orleans, La.

March 18-22, 2012ACI Spring ConventionHyatt Regency DallasDallas, Tex.

April 16-17, 2012ASBI 2012 Grouting CertificationTraining

J.J. Pickle Research CampusThe Commons CenterAustin, Tex.

May 20-25, 201214th International Conferenceon Alkali-Aggregate Reactions inConcreteHyatt Regency AustinAustin, Tex.

June 10-13, 2012International Bridge ConferenceDavid L. Lawrence Convention CenterPittsburgh, Pa.

July 7-12, 20122012 AASHTO Subcommittee onBridges and Structures MeetingHyatt RegencyAustin, Tex.

July 23-27, 2012 (Tentative)2012 PCA Professors WorkshopSkokie, Ill.

September 29-October 3, 2012PCI Annual Convention andExhibition and National BridgeConferenceGaylord Opryland Resort & ConventionCenterNashville, Tenn.

For links to websites, email addresses, or telephone numbers for these events, go towww.aspirebridge.org and select EVENTS.

Photo:Ted Lacey Photography.
https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=https://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=http://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.asbi-assoc.org/index.cfm/events/eventshttp://www.asbi-assoc.org/index.cfm/events/eventshttp://www.asbi-assoc.org/index.cfm/events/eventshttp://www.asbi-assoc.org/index.cfm/events/eventshttp://www.asbi-assoc.org/index.cfm/events/eventshttp://www.asbi-assoc.org/index.cfm/events/eventshttp://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.worldofconcrete.com/http://www.worldofconcrete.com/http://www.worldofconcrete.com/http://www.worldofconcrete.com/http://www.worldofconcrete.com/http://www.worldofconcrete.com/http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.dfi.org/conferencedetail.asp?id=163http://www.concrete.org/EVENTS/ev_upcoming_conventions.htmhttp://www.concrete.org/EVENTS/ev_upcoming_conventions.htmhttp://www.concrete.org/EVENTS/ev_upcoming_conventions.htmhttp://www.concrete.org/EVENTS/ev_upcoming_conventions.htmhttp://www.concrete.org/EVENTS/ev_upcoming_conventions.htmhttp://www.concrete.org/EVENTS/ev_upcoming_conventions.htmhttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.asbi-assoc.org/index.cfm/grouting/traininghttp://icaar2012.org/http://icaar2012.org/http://icaar2012.org/http://icaar2012.org/http://icaar2012.org/http://icaar2012.org/http://icaar2012.org/http://icaar2012.org/http://bridges.transportation.org/Pages/default.aspxhttp://bridges.transportation.org/Pages/default.aspxhttp://bridges.transportation.org/Pages/default.aspxhttp://bridges.transportation.org/Pages/default.aspxhttp://bridges.transportation.org/Pages/default.aspxhttp://bridges.transportation.org/Pages/default.aspxhttp://bridges.transportation.org/Pages/default.aspxhttp://www.cement.org/learn/professors_workshop.asphttp://www.cement.org/learn/professors_workshop.asphttp://www.cement.org/learn/professors_workshop.asphttp://www.cement.org/learn/professors_workshop.asphttp://www.cement.org/learn/professors_workshop.asphttp://www.aspirebridge.org/http://www.aspirebridge.org/http://www.cement.org/learn/professors_workshop.asphttp://bridges.transportation.org/Pages/default.aspxhttp://icaar2012.org/http://www.asbi-assoc.org/index.cfm/grouting/traininghttp://www.concrete.org/EVENTS/ev_upcoming_conventions.htmhttp://www.dfi.org/conferencedetail.asp?id=163http://www.worldofconcrete.com/http://www.trb.org/AnnualMeeting2012/AnnualMeeting2012.aspxhttp://www.pci.org/markets/certifications/school_details.cfm?sid=2http://www.asbi-assoc.org/index.cfm/events/eventshttp://www.usbr.gov/pmts/tech_services/training/concrete.htmlhttp://www.tsp2.org/files/2011/03/NBMIP_Conference_2011.pdfhttps://netforum.pci.org/eweb/DynamicPage.aspx?webcode=EventInfo&action=add&evt_key=da9c6f13-4908-4168-96ef-5a05ca47b67b&Paying=


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FOCUS

8|ASPIRE, Fall 2011

Contractors usually call on McNaryBergeron & Associates only when thegoing gets toughand thats just theway the companys engineers like it.The firm specializes in taking complexdesigns and making them moreconstructible, ensuring the ownerand designers vision becomes reality.That has led the 8-year-old company

into some high-profile and extremelychallenging concrete projects.

We usually get involved in projectsthat are complex, says Scott McNary, aprincipal in the Broomfield, Colo.-basedconstruction engineering firm. We workon the problem children, the projectsthat are difficult to build. And we enjoythose challenges. The companys goalis simple, adds Principal Jim Bergeron,who heads the firms other office in OldSaybrook, Conn. Our niche is to help

contractors and designers be successful.

We can bridge the gap between designand construction because we speak bothlanguages.

The firm was founded in 2003 byMcNary and Bergeron along withJeremy Johannesen. All three hadexperience with large engineering firmsprior to partnering. We wanted to get

back to our roots of working directlywith contractors to help them withthe construction of complex bridges,Bergeron says. Since easily designedprojects seldom need constructionengineering support, the engineersusual ly are working on complexprojects. Those often involve concreteconstructionor ones that becomeconcrete during the value-engineeringprocess, says Johannesen.

We do some designing, especially

when value engineering is required,

he says. But 90% of our work isconstruction engineering of existingdesigns to make them more efficient tobuild.

Fast Start withHoover DamMost commiss ions resu l t f romrelat ionships with designers orcontractors with whom the partnershave worked on past projects,McNary explains. Those connectionshelped them become part of a high-profile project shortly after the firmwas created: The Hoover Dam BypassColorado River Bridge in Nevada andArizona.

The company provided constructionengineering services for the cast-in-place arch structure and thetemporary stay-cable system used tosupport it. That work included designof the anchorages, towers, and cable

construction for the arch ribs as wellas the rib shop drawings and anindependent review of the form-travelerdesign.

There were many challenges involvedin bringing that design to fruition, saysJohannesen. We basically worked withthe contractor to create a tower andanchorage system that would streamlinethe concrete construction. The endresult worked extremely well.

The companys expertise in arch workpaid off when it became involved inthe Covered Bridge over the KennebecRiver in Norridgewock, Maine, whichhas just been completed. The projectfeatures a cast-in-place concretetied arch spanning 300 ft. McNaryBergeron provided construction analysisfor the new arch and erection plansand procedures, as well as design ofthe temporary arch shoring and ademolition plan for the existing arches.(See the article on this bridge on page

34.)

by Craig A. Shutt

Bridging the Gap

McNary Bergeron provided construction engineering for the cast-in-place arch structure and

temporary stay-cable system used to support the Hoover Dam Bypass Colorado River Bridge.It was one of the first high-profile projects for the company, which was founded in 2003. All

photos: McNary Bergeron & Associates Inc.

McNary Bergerons construction engineering work

helps ensure efficient and cost-effective construction


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There is nothing similar to this inMaine, or even in most of the country,says Bergeron. Its a complicated archstructure, but its very distinctive andmemorable.

Contractor ModificationsMuch of the work the firm does falls

under the heading of contractormodifications, which it performsfor most of its projects, rather thanvalue engineering, which it doesless frequently, McNary explains.Construction modifications leave thestructural engineering as it is, withonly some aspects changing. For value-engineering work, the firm changes theshape or materials being used, makingsubstantial alterations to better suit thecontractors needs and expertise.

A n e x a m p l e o f c o n s t r u c t i o nmodifications can be seen in theRoute 36 Highlands Bridge over theShrewsbury River in Monmouth County,N.J. The new design, which replaced aworn-out 1932 structure, was designedas a two-span fixed, four-lane, precastconcrete segmental box structure witha 65-ft clearance (raising the previousclearance by 30 ft).

McNary Bergeron helped designthe precast concrete cofferdamsa n d s u p p o r t s y s t e m s f o r t h e

footing construction and providedintegrated shop drawings for precastconcrete column and superstructuresegments. I t also developed anddesigned the falsework, cantilever-stabil ity system, l ifting assemblies,and rigging. All of the componentswere barged to the site because landaccess was difficult.

The key to the project was speed ofconstruction, explains Bergeron. Eachof the twin bridges had to be erected ina construction season. The total-precastconcrete design allowed portions to becast in advance and floated to the sitefor erection. Aesthetics also played arole in the structure type, he notes. Its

a very visible structure, so aestheticswere especially important to theowners.

The firm currently is working on thedesign for a similar project, the VeteransMemorial Bridge Replacement inPortland, Maine, as part of a design-build team. McNary Bergeron createdthe constructabil ity review of thetwin-bridge superstructure, providingrecommendations on segment layout,post-tensioning details, fabrication anderection efficiencies, and alternativeerection procedures. The bridge featuresspan lengths up to 250 ft, with precastunits by the same precaster used on theRoute 36 Highlands Bridge. The bridgewas designed to replicate some of theRoute 36 bridge plans, allowing theprecaster to reuse the forms, therebysaving costs.

There are often many ways toconstruct a bridge, and we alwayssteer the design to favor repetition ofcomponents to take full advantage

of precast concretes capabilities,says McNary. These ideas help thecontractor be more efficient, whichsaves money.

Value-Engineering WorkValue-engineering projects includethe Nalley Valley Interchange on I-5through Tacoma, Wash. We assisted

the contractor in procuring the contractby redesigning two expensive steelbridges to more economical concrete

structures, says Johannesen. Aspart of that, the SW Line Bridge wasredesigned from a steel tub-girderbridge to a precast concrete segmentalbox girder design.

The alignment was well suited tothe precast segmental design, so wemaintained the alignment but designedthe bridge for concrete. We createdthe basic configuration that best suitedthe contractor and the precaster forcasting and handling the components

the whole way through the project.The change also suited the ownerbecause of the extended design lifeand reduced maintenance.

A dramatic cast-in-place concrete tied

arch with steel cable hangers serves as the

key visual element on the Covered Bridge

over the Kennebec River in Norridgewock,

Maine. The design is the first of its type

in the state and in the eastern half of the

United States. McNary Bergeron provided

construction analysis for the new arch,

which spans 300 ft.

Projects in Aspire

Projects in which McNary Bergeronparticipated were featured in thefollowing ASPIRE articles, which canbe viewed in the Magazine section atwww.aspirebridge.org:

San Francisco-Oakland Bay Bridge(Winter 2007)

Susquehanna River Bridge (Spring2007)

Selmon Expressway (Fall 2007) Seattle Sound (Spring 2008) Maroon Creek (Spring 2008) Washington Bypass N.C. (Fall 2008) Folsom Lake Crossing (Winter 2009) Crosstown Project (Minn.) (Spring

2009) Fulton Road Bridge (Spring 2009) Galena Creek Bridge (Winter 2010) Hoover Dam Bypass, Colorado River

Bridge (Spring 2010) Route 36 Highlands Bridge (Summer

2010) Nalley Valley Interchange (Summer

2011) MIC-Earlington Heights Connector

(Summer 2011)

ASPIRE, Fall 2011 |9
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The temporary br idge that wasto provide access while the newbridge was constructed was value-engineered from a steel design intoa precast concrete bulb-tee girderdesign. Precasters can cast deckbulb tees with specified camber, sowe dont create haunched buildupconstruct ion, McNary expla ins.The owners l iked th is des ign,

because it simplified the constructionand provided the image that thetemporary bridge could last as long asneeded.

A design-build contractor will oftenhave a construction engineer on his

team. A key reason is the capabilityto maximize speed of construction,Johannesen adds. Speed is moreimportant all the time. Owners arelooking at all of the costs and realizingthat the faster they can complete theproject, the more they can save in laborand user costs. We help that by findingways to do engineering and fabricationof components ahead of time. The

more time spent upfront before gettingto the site, the more efficient theprocess will be.

Speed is a key focus, becausealmost every project is a replacementproject that is in high use already,

says Bergeron. There are few newbridges being built. Almost always, weare taking something down to put up anew structure.

New TechniquesAid Efficiency

The engineers are keeping a close eyeon techniques that will help achievethat goal, including the use of self-propelled modular transporters (SPMTs).There are a number of new pieces ofequipment and devices that hold a lotof promise for making it more efficientto construct bridges, Bergeron says.

Advances are being made especially forhandling precast concrete components,agrees Johannesen. Beams and girdersare getting larger as creative waysare found to transport and maneuverthem, he says. As soon as cranesget bigger, a new girder is designed totake advantage of their capabilities.Mobile lifting cranes and gantries alsoare getting more robust, he says.

New equipment will make bridgedesigns more efficient to build, addsBergeron. It always comes down tocost, and if a crane can be used, thatsthe way to go. So as cranes get moreversatile, they become even morepopular. Especially when land access

is limited, its important to have otherways to access the site, and betterequipment is helping to meet tighterschedules and budgets.

Tendon-grouting with segmentaldesigns has grown in importance, with

Speed of construction was a key reason that McNary Bergeron helped create the all-

precast concrete design for the Route 36 Highlands Bridge over the Shrewsbury River in

Monmouth County, N.J. Each of the twin bridges were cast and erected in a construction

season, providing access year round while construction continued.

The Nalley Valley Interchange on I-5 through Tacoma, Wash., represents one of the few value-engineering projects that McNary

Bergeron has done. The two bridges were redesigned from steel tub-girders to a precast concrete segmental box-girder design. The

change reduced costs while maintaining the original alignment.


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new requirements for post-tensioningsystems creating more complexities.The growing use of duct couplersoffers a wide-open field for building abetter mousetrap, says Johannesen.The couplers are cast into the concreteduring match-casting procedures, and

then broken apart so the second couplercan be cast into the next component toensure an air-tight seal.

Higher compressive strengths thatprovide longer, lighter concrete spansalso offer potential, McNary says. Thefirm is using more 75-ksi reinforcementin its designs as well as looking closelyat superstrand, which provides a 7%larger cross-sectional area for use withpost-tensioning.

Such technologies and techniques willadd new weapons to McNary Bergeronsarsenal, helping to meet challengesas bridges grow in complexity. Weare advocates for contractors, toensure bridges are built efficiently andeconomically, says McNary. We can

have a big impact on the industry asa whole by working closely withcontractors to ensure projects go theway the contractor needs them to go.That can create innovative approachesthat others can use.

For additional photographs orinformation on this or other projects,visit www.aspirebridge.org and openCurrent Issue.

Bridges to Prosperity

The founders of McNary Bergeron believe in giving back to their own community and to the world community. They have maximized the useof their own skills while meeting this goal by working with Bridges to Prosperity Inc. The group literally builds bridges between people inunderdeveloped countries, via pedestrian suspension bridges. The work helps connect remote areas, making it easier to access food and medicalhelp.

Although mountainous areas provide easy design opportunities for suspension bridges, about half of the organizations bridges span flat floodplains with no natural features from which to suspend bridges. McNary Bergeron saw an opportunity to help overcome that obstacle in 2005, saysJeremy Johannesen, who serves on the organizations Advisory Board. Scott McNary also serves on the groups Executive Board.

We work with them to design suspension towers so they can get above the water more easily, Johannesen explains. When problems arise, we

work with the contractors to solve them. Frequently, that has included personnel from Flatiron Construction, which began volunteering with thegroup in 2008. The firm sends young engineers to help build these bridges to gain real-life experience.

An example is the La Pintada suspension footbridge over the Rio Copan in Honduras, which was constructed in the spring of 2010. The fourcommunities that lay beyond the river can now safely cross the waterway during high-water season. The challenge was immense, but the productincredibly rewarding, Johannesen says. Based on the relationships built during this project, he adds, future Bridges to Prosperity projects in thearea may be on the way.

McNary Bergerons work with

Bridges to Prosperity Inc. has

included La Pintada suspension

footbridge in Honduras. This bridge

connects four formerly inaccessible

communities. The firm helped

design the structural towers that

support the bridge on the low-lying

plain, which had been an obstacle to

creating the bridge previously.

By designing Veterans Memorial Bridge

Replacement in Portland, Maine, in

a similar style to the earlier Route 36

Highlands Bridge in New Jersey, McNary

Bergeron allowed the precaster, who was

the same for both projects, to reuse the

original forms, saving costs.

ASPIRE, Fall 2011|11
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CREATIVE CONCRETE CONSTRUCTION

12|ASPIRE, Fall 2011

Concrete, an old material cast in a newway, cla ime d top pos it ion in the ARC

International Wildlife Crossing InfrastructureDesign Competition. Calling for New Methods,New Materials, New Thinking, the competitionpresented a mighty challenge to the worldsdesign community: Develop a feasible, buildable,context-sensitive, and compelling designsolution for a safe, efficient, cost-effective,and ecologically responsive wildlife crossingstructure.

HNTB Engineering with Michael Van

Valk en burg h Assoc ia te s Inc. and Ap pl ie dEcological Services Inc. (HNTB+MVVA)responded to the engineering and ecologicalchallenge and won with hypar-natureahypar (hyperbolic parabaloid) vault. Theirdesign may set the precedent for the nextgeneration of infrastructure that re-connectswildlife habitats bisected by roads.

The hypar-nature bridging systemconsists of precast modules that serve asabutment, beam, and deckall in one. Thissingle elementcreated using straight line,commercially available formworkis the key

to cost-effectiveness, speed of construction,and modularity. Two modules are joined atthe midspan acting as a three-hinged arch,eliminating the need for a center pier. No on-siteconcrete work is required. Instead, the hyparmodules are optimized for being efficient totransport, erect, combine, and recombine asneeded. The same modules, oriented differently,can also incorporate bicycle paths separatedfrom traffic and the wildlife crossing above.*

The five-expert jury, chaired by CharlesWaldheim of Har vard Univer sit ys Graduate

School of Design, determined that HNTB+MVVAsproposal marries well a simple elegance witha brute force. It effectively recasts ordinarymaterials and methods of construction into apotentially transcendent work of design. . .it could

be credibly imagined as a regional infrastructureacross the intermountain west. One jurorsummed up the jurys collective thoughts,The winning proposal by HNTB+MVVA is notonly eminently possible; it has the capacity totransform what we think of as possible.

The ARC Competition concluded in January2011, but the ARC Partnership continuesto collaborate in support of wildlife crossinginfras tructure for improved landscapeconnectivity and highway safety (www.arc-competition.com).

* Specif icatio ns a bout hypar-naturewere drawn dir ectly from HNTB+MVVAssubmission.

_______

Angela Kociolek is a research scientistwith the Western Transportation Institute

at Montana State University in Bozeman,

Mont., and is the technology transfer

initiative leader for the ARC Partnership.

"hypar-nature"A precast concrete design for wildlife crossings

by Angela Kociolek, Western Transportation Institute at Montana State University

Model depicting the construction process. Note temporary falsework in place as a central pier, the one-crane operation

using a balanced pick point, and maintenance of traffic flow along one side of the roadway. All images: ARC.

In an artists rendition, the hypar-nature design

appears to seamlessly connect habitats on both either sides

of the roadway. Best management practice is to install

8-ft-tall wildlife fencing in combination with crossing

structures. This reduces wildlife-vehicle collisions on the

roadway while guiding animals towards the structure.

HNTB+MVVAs winning design offers hope that mobility for people and wildlife does not have to be mutually exclusive.
http://www.arc-competition.com/http://www.arc-competition.com/http://www.arc-competition.com/


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Long, arching spans and tall, slenderpiers create an elegant concretes e g m e n t a l b r i d g e a c r o s s t h eMonongahela River near Brownsville,Pa. Value-engineering the project froma steel plate-girder design saved $8.5million while addressing challenges inthe planning and construction phases toproduce a unique design.

The bridge is part of an extensiveexpans ion to the Mon-Fayet teExpressway that supports efforts bythe National Road Heritage Park.The projects goal is to provide relieffor Route 40, shifting it from a majortransportation artery to more of a local

traffic corridor and tourist destination.The bridge accomplishes this byimproving access, addressing futurecapacity requirements and drawingtraffic (especially trucks) off Route 40and onto more modern throughways.The project closes a gap in the systembetween U.S. Route 119 in Uniontownand PA Route 88 in California, Pa.

Filling the gap required approximately17 miles of new limited-access highwaycosting $605 million. The bridge, amajor new crossing of the MonongahelaRiver, consists of 12 major sections, withthis new structure commonly referred toas Section 51H.

Value-Engineered SavingsThe Pennsylvania Turnpike Commissionprovided the opportunity for analternate-design concept to the originalsteel design. That led FIGG to teamwith Walsh Construction to create asegmental-concrete option that wasconsiderably more efficient. Walshspersonnel had experience with thisdesign type and were confident of theirapproach.

In part, that was due to their successfulconstruction of a similar design, alsoproduced by FIGG, for the nearby I-76Allegheny River Bridge in Cheswick,Pa. (See ASPIRE, Spring 2009.) Thatproject consisted of a 2350-ft-longstructure with 100-ft-tall piers andfeatured the first use of balancedcantilever construction in Pennsylvania.That similarity for a recent design andlocal accessible expertise ensured an

effective and efficient project for thenew structure.

The impact of tall piers, limited access,and river, road, and railroad crossingson the construction was minimizedby using balanced cantilever concretesegmental construction. To maximizesavings, pier locations were adjusted to

profile MON-FAYETTE EXPRESSWAY BRIDGE/ BROWNSVILLE, PENNSYLVANIABRIDGE DESIGN ENGINEER:FIGG, Philadelphia, Pa.

CONSTRUCTION MANAGEMENT/CONSTRUCTION INSPECTION:SAI Consulting Engineers, California, Pa.;Finley Engineering Group, Tallahassee, Fla.

PRIME CONTRACTOR:Walsh Construction Co., Canonsburg, Pa.

CONCRETE SUPPLIER:Stone & Company, Charleroi and Uniontown, Pa.POST-TENSIONING CONTRACTOR:Schwager Davis Inc., San Jose, Calif.

by Brice Urquhart, FIGG, and James Stump, Pennsylvania Turnpike Commission

A TALL ORDERValue-engineering creates a tall, elegant concrete segmentaldesign for the Pennsylvania Turnpike

This rendering of the Monongahela

Bridge, still under construction until next

spring, shows the sleek design of the

superstructure that complements thepiers that are up to 200 ft tall. All photos,

drawings, and rendering: FIGG.

14|ASPIRE, Fall 201114|ASPIRE, Fall 2011

PROJECT


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12 (Shoulder)

12

12 (Shoulder)12 (Lane) 12 (Lane)12 (Lane)12 (Lane) 5 - 9(SHLDR.)

48 - 5 1/2

89 - 4 1/2

5 - 9(SHLDR.)

2

3-4

6

12

9 - 514 - 2

33

30

1-6(TYP.)

eliminate two piers and provide a designmore efficient for a concrete segmentalbridge. The pier closest to the riverbank on both sides was retained in itsoriginal position to speed the permittingprocess.

The design concept was bid by thecontractor and approved by thePennsylvania Turnpike Commissionbefore final design drawings werecompleted. The project proceeded on afast-track basis, with initial constructionof foundations beginning as laterdrawings were being completed.

The fast-track process required aclose relationship between Turnpikeofficials and the contractor, so theycould work quickly through design-

review meetings and facilitate reviews.This communication ensured thatapprovals were received in a timelymanner so the contractor could proceedwith foundations, piers, and thesuperstructure as the plans and projectsite were ready.

The 3022-ft-long bridge features sevenspans, with a configuration of 259,490, 490, 518, 504, 497, and 264 ft.The concrete segments consist of 89-ft4-in.-wide, dual-cell box girders with

a center-web thickness of 2 ft and anoutside-web thickness of 1.5 ft. Thesegment depth varies from 12 ft atmidspan to 27 ft 2 in. at the river piers

and 26 ft 7 in. at the land piers. Thedeck has an 11-in. minimum thickness.The bottom slab thickness varies from3 ft 10 in. at the pier tables to 10 in.at midspan. The dual box design waschosen due to the wide structure,which carries four 12-ft-wide lanes, two12-ft-wide shoulders, and a 14-ft-widemedian.

200-Ft-Tall PiersThe key challenge came in designingthe six piers, which range in heightfrom 100 to 200 ft. That significantheight required a sleek design that wasin keeping with the thin profile of thesuperstructure, which was minimizedfurther by the tall piers.

The piers were cast with 15-ft-tall jump

forms that were advanced upward aftereach lift of concrete was placed andcured. The specified 28-day concretecompressive strength was 5500 psi.The two piers at the river banks wereoctagonal in shape with a 50-ft-tall solidconcrete base to resist barge impacts,with the remaining 150 ft cast with ahollow center.

The approach piers further awayfrom the river were designed as two,C-shaped, walled structures. They used

the octagonal river pier shape split intwo. This design aided flexibility andload-sharing via the twin walls andhelped to balance the superstructure

during construction while maintaining aconsistent look to all of the piers.

The bridge is on a tangent alignment,and the deck is cast with cross-slopesto allow for drainage in both directions.Turnpike officials also had concernswith sulfate levels in the soils due to alocal mining quarry. To alleviate thoseconcerns, the footing and first lift of Pier6 and Abutment 2 concrete elementswere cast with moderate sulfate-resistant concrete using Type II cement.

The pier design was created to enhancethe efficient and sleek appearance ofthe segmental superstructure. The goalwas to eliminate wasted concrete and

CAST-IN-PLACE CONCRETE SEGMENTAL BOX-GIRDER BRIDGE BUILT IN BALANCED CANTILEVER ON CAST-IN-PLACE CONCRETE PIERS / PENNSYLVANIA TURNPIKE COMMISSION, HARRISBURG, PENNSYLVANIA, OWNER

BRIDGE DESCRIPTION: Seven-span, 3200-ft-long, two-cell concrete segmental box-girder bridge with spans of 259, 490, 490, 518, 504, 497, and264 ft, and with concrete piers 100 to 200 ft tall

STRUCTURAL COMPONENTS:Variable-depth, two-cell cast-in-place concrete segments that vary from 12 ft to 27 ft 2 in. deep with an 89-ft 4-in.-wide deck, two octagonal concrete piers at the river, and other piers shaped like the river piers split apart into twin walls

BRIDGE CONSTRUCTION COST:$95 million

Monongahela River Bridge pier crosssection for C-shaped piers on land.

Monongahela River Bridge box girder cross section at mid-span.



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minimize the structure in the piers, piercaps, or superstructure to ensure nodisruptions to the smooth lines. Thepiers provide a look that respects thecontext of the site, creating a differentappearance from every perspectiveowing to their geometric shapes.

Limited Site AccessThe balanced cantilever method wasused on the project due to the limitedaccess at the site. Using cast-in-placeconcrete with form travelers minimizedequipment on the ground andequipment to lift components 200 ftin the air. However, the remote projectarea and tall piers created challengesfor concrete p lacement for thesuperstructure. Concrete was pumpedfrom the ground to the forms.

The box g i rde r s f ea tu re l ow-permeability concrete with a specifiedcompressive strength of 6000 psi. Closecommunication with the contractor andthe ready-mix concrete supplier ensuredthere was a steady flow of concrete forsegment casting requiring as much as180 yd3. This portion of the work wasfairly typical except for the exceptionalheights involved. The bridge is locatedin a fairly remote portion of the state,with few concrete plants in the area, sologistics were a key part of the planning

for the project.

The concrete superstructure was castyear round, including the harsh wintersof western Pennsylvania. This requiredmore attention to curing methods,which consisted of using enclosures,heating elements and wet burlap onthe deck. Epoxy-coated reinforcementwas used in the deck as well as anybars extending into the deck, includingdiaphragm and web reinforcement.

Four Form Travelers UsedConstruction of the superstructure,which is nearing completion, isbeing accomplished with four formtravelers, two per cantilever, allowingtwo cantilevers to be constructedsimultaneously. Cantilevers 2 and 5were cast first, followed by 3 and 6.Cantilevers 1 and 4 are being completedthis fall, with finishes and other detailwork expected to be completed byspring 2012.

In all, 51,000 yd3of concrete, 7 millionlb of reinforcing steel and 3 million lbof post-tensioning tendons are beingused in the project. After each pairof segments is completed, they arepost-tensioned both transversely andlongitudinally with cantilever tendonswithin the deck. Once the spans areclosed between the cantilevers, thecontinuity tendons along the bottomslab and draped tendons that extendfrom pier to pier are stressed tocomplete the span.

When the bridge is completed in thespring, users will benefit by having adistinctive concrete structure set againsta lush environment and constructed atlow cost. The bridge will ease accessin the area well into the future. Evenbetter, it provides a best-value solutionfor the Pennsylvania Turnpike and adurable bridge that will benefit users for100 years or more.

__________

Brice Urquhart is regional director with

FIGG in the Northeastern regional office

near Philadelphia, Pa., and Jim Stump is

the Bridge Engineering Manager at the

Pennsylvania Turnpike Commission in

Harrisburg, Pa.


The bridge is constructed using balanced cantilever construction, with seven spans

including a main span of 518 ft and piers up to 200 ft tall. Construction of the final

cantilevers at Piers 1 and 4 are underway as bridge construction enters the final stages.

Pier tables begin the balanced cantilever

superstructure construction.



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The Northeast 36th Street Bridge and

roundabout intersection in the city ofRedmond, Wash., located 15 milesnortheast of Seattle, was completed andopened to traffic in December 2010. Thenew bridge, a landscaped lid offeringmany pedestrian amenities, provides anovercrossing of State Route 520, whichincludes the well-known floatingbridge that connects Redmond, thehome of Microsoft World Headquartersand the University of Washingtoncampus.

The new 414-ft-long bridge measuredalong the travelled way, connects

two sides of the expanding Overlake

neighborhood in Redmond, over SR520, and adjoins a recently expandedMicrosoft campus. The two arterialsconnected by the Northeast 36th StreetBridge are some of Redmonds mostcongested roadways. The new bridgewill help to alleviate bottlenecks onnearby interchanges and the impactsof the projected population andemployment growth in the Overlakearea. Without the new bridge, theexisting connections over SR 520 wouldbe overwhelmed. The project is expected

to reduce vehicle miles travelled byapproximately 135,000 miles per year.

In keeping with Redmonds designation

as the b i cyc le cap i ta l o f theNorthwest, the Northeast 36th StreetBridge is optimized for pedestrian accessand bicycle connections. It providesone traffic lane in each direction, bikelanes, sidewalks, and intersectionimprovements. It also accommodatesthe future Sound Transit Link Light Railalignment and a connecting pathwaythat offers pedestrian access to thenearby Transit Center.

Double-Diamond Plan

The bridge passes diagonally overSR 520 and, according to Redmondsproject manager, Dennis Apland, is theproduct of a lot of clever engineering.The roadway crosses the highwayat a 44-degree angle, rather than themore typical 90 degrees. The projectis essentially two offset adjoininglandscaped lidsa unique and innovativesolution that prevented the project frombecoming a much more costly tunnelproject. The length of each lid along SR520 is approximately 300 ft, just shy of

the length that would trigger expensivefire suppression and ventilation systemsfor a tunnel designation.

The double-diamond design allowedthe bridge to be built using standardconstruction methods, producing a muchmore cost-effective project overall. Thissolution also yielded minimal constructionimpacts on the major highway below.

profile NORTHEAST 36TH STREET BRIDGE OVER SR 520/ REDMOND, WASHINGTONBRIDGE DESIGN ENGINEER:BergerABAM, Federal Way, Wash.

GENERAL CONTRACTOR:Tri-State Construction Inc., Bellevue, Wash.

PRECASTER:Concrete Technology Corporation, Tacoma, Wash., a PCI-certified producer

REINFORCEMENT SUPPLIER:Pacer Steel Inc., Pacific, Wash.

BRIDGE DESCRIPTION: Two spans (150 and 164 ft by 300 ft wide) providing a traveled way bridge length of 414 ftsupported on cast-in-place concrete abutments and a concrete center pier

by Robert L. Fernandes, Ross A. French, and S. Ping C. Liu, BergerABAM

Creating a Level Playing Field

The signature design of the Northeast

36th Street Bridge is the unique double-

diamond shape, approximately 50,000ft2landscaped lid spanning SR 520. All

photos: BergerABAM.

A BRIDGE AND A PARK BUILT OVER BUSY FREEWAY



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A key challengefor the structural designwas the center pier andthe structures seismicdemands.

Design Challenges andAlternativesThe alignment was originally plannedto cross SR 520 at approximately a60-degree skew. This skew, combinedwith limited space for a bridge pier inthe median of SR 520 and the needto keep the abutments out of the280-ft-wide right-of-way, created someunique challengesand opportunitiesfor the project participants. At a60-degree skew, a new br idgeconstructed parallel to the proposedroadway alignment would have been atwo-span structure, approximately 560ft long with spans of approximately 280ft. Structure depth and profile issueswould have required radical changesto property access on either side of thecrossing.

The arrangement of offset landscapedlids reduced the overall deck areathat would have been required for aconventional continuous lid. It reducedthe roadway alignment skew to about

45 degrees and allowed the lid to crossSR 520 at approximately 25 degrees.The resulting span lengths were 150

ft and 164 ft for the westbound andeastbound lids, respectively, whichallowed the use of precast, prestressedconcrete beams for the superstructure.This solution provided a vibranturban connection for users, and wasarchitecturally compatible with the othernearby crossings.

Structural Design FeaturesThe framing consists of 56, WSDOTWF83G, precast, prestressed concretebulb-tee beams. The beams are 83 in.deep and feature a 49-in.-wide topflange. The beams were spaced at about6 ft 4 in. in the 150-ft-long westboundlid and at 5 ft 0 in. in the 164-ft-longeastbound lid, almost flange to flange.The close spacing was a direct result ofthe need to design the landscaped areasof the lid for a total load of 510 lb/

ft2, in addition to the standard highwayloadings under the roadway portion.The specified concrete compressivestrength was 10,000 psi. The beamsused 0.6-in.-diameter strands for the38 or 42 straight strands and 22 or 24harped strands.

Completion of the cast-in-placeconcrete deck was complicated by the

geometry of the project. In order tosimplify the casting, an unbroken planarsurface was specified. The deck overthe beams varied in thickness from 8 to10.5 in. The top mat of reinforcing steelwas epoxy coated. The roadway crownsection was accomplished with asphalt,varying in thickness from 2 to 6 in. Theremainder of the deck was covered withsoil up to 36 in. deep.

A key challenge for the structural designwas the center pier and the structuresseismic demands. To maintain WSDOTstandards for shoulder widths andsight distance on SR 520, the widthof this pier could not exceed 6 ft. Thisconstraint, combined with the need tolet the offset beams rotate freely andindependently due to the deck weightand landscape surcharge, required

the introduction of an expansionjo in t at the center pier where thetwo offset lids overlapped. This jointallows rotation, but was detailed toprevent horizontal movement of thesuperstructure, relative to the pier, inboth the transverse and longitudinaldirection. This, in-turn required theabutments to be founded on a seriesof fourteen 6-ft-diameter drilled shafts.The shafts were not required for verticalload but were required to create a deepabutment wall capable of developing

the passive pressure required to limitthe longitudinal movement of the twospans in a seismic event. The center pier

TWO DIAMOND-SHAPED OFFSET LIDS OVER A DIVIDED FREEWAY USING PRECAST, PRESTRESSED CONCRETEBULB-TEE BEAMS AND CAST-IN-PLACE CONCRETE DECK WITH CENTER PIER USING PRECAST CONCRETECOLUMNS PROVIDING A DIAGONAL ROADWAY AND UNIQUE MEANDERING PEDESTRIAN WALKWAYS / CITY OFREDMOND, WASHINGTON, OWNER

STRUCTURAL COMPONENTS:Fifty-six WSDOT bulb-tee beams, 83 in. deep with 49-in.-wide top flanges with cast-in-place composite concretedeck 8 to 10.5 in. thick and 14 precast concrete columns, 4 ft by 4 ft by 29 ft 5 in. tall in the center pier

BRIDGE CONSTRUCTION COST:Bridge: approximately $10 million; Total: $21.4 million

Excavation of the 250-ft-long central pier occurred during live traffic. During the setting

of the center pier columns and the concrete placement for the center pier footing, up

to two lanes of SR 520 were closed in each direction.

Construction of the center pier in the

median of SR 520 required a 16-ft-deep

shored excavation for the spread footing

foundations.



22/60

itself was approximately 260 ft long,consisting of 14 columns supported ona 10-ft-wide spread footing. The centerpier provides only vertical support forthe structure, as its lateral movementsare limited.

Precast Concrete ColumnsConstruction of the center pierspread footing in the median of SR520 required a 16-ft-deep shored

excavation. Because WSDOT waspaving SR 520 at the time the projectwas bid, construction of this pier wasdelayed by 6 weeks. Because the beamsupplier was extremely busy at thistime, the 6 week delay was projectedto have a ripple effect on the deliveryand erection of the beams, and thesubsequent completion of the deckconstruction and approach paving.The weather-sensitive approach pavingand substantial completion of theproject would be delayed by as muchas 6 months. In order to expedite theconstruction of the center pier andrecover the schedule, a decision wasmade to redesign the 14 columns tobe precast concrete rather than cast-in-place. The columns were cast onsite and erected in the median where

footing cages had been assembled. Thisrecovered about 4 weeks of the original6-week delay, allowing the remainderof the pier construction and beamerection to proceed in accordance withthe contractors original plan to pave theapproaches and complete the project inthe fall.

__________

Robert L. Fernandes is vice-president, RossA. French is project engineer VI, and S.

Ping C. Liu is communications manager, all

with BergerABAM in Seattle, Wash.


Fourteen columns were precast and

erected in the median, recovering 4

weeks of potential project delays.

The Northeast 36th Street Bridge includes one through-lane in each direction. Bicycle

lanes, generous sidewalks, and lush landscaping are included. The roadway crosses SR

520 at a 44-degree angle, rather than the more typical 90 degrees.

Precast columns . . . recovered about 4 weeks

of the original 6-week delay.

Respecting theEnvironment throughInnovative Engineering

The Northeast 36th Street Bridge prioritizedenvironmental design and is optimizedfor pedestrian and bicycle access and an

enhanced user experience. Its featuresinclude the following: Reduced the amount of impervious

surface that blends seamlessly into thesurrounding environment.

The illusion to the user of not beingon a bridge as views and noise areblocked by the attractive landscapingand bridge barrier.

Park-like amenities and ample lightinginstalled for public safety, comfort, andenjoyment.

Wide, meandering sidewalks separatedfrom the automobile zone by planterstrips and connected to all majoraccess points and local businessesincluding the use of ramps, crosswalks,and handrails.

A direct connection to a multiuse pathand popular 5-mile interurban trailsystem to maximize community andsustainability elements.

Bridge barrier raised by approximately3 ft relative to a typical barrier. Raisedplanted islands block noise and visualdistractions. Undulating sedimentarywalls constructed at the sidewalk edge

provide seating and a barrier fromthe landscaped beds. These plantingsreduced the area of impervious surfaceand absorb storm water before addingto runoff. A bridge drain system,including a waterproofing membrane,drainage mat, and an inlet and pipesystem collects additional water onthe bridge and delivers it to the citysstormwater system.

The number of trees removed fromthe site was minimized. Extensiveplantings restored the site to its pre-

built condition. No new roadwayswere created as part of the project.

On-site rocks were re-used to createnew rock walls adjacent to theroadways.

Shallower beams were used than ifthe structure was built on a largerskew. This avoided the need for specialcranes and larger equipment. It ledto reducing the size of walls andthe quantity of fill at the ends of thebridge, which also reduced the cost ofthe project.



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ELEVATION

The San Bernardino Mountains havelong provided a key recreational outletfor the millions of residents populatingthe valleys and coastlines of sunnysouthern California. Big Bear Lake issituated approximately 100 miles eastof Los Angeles in the San BernardinoNational Forest at an elevation of6752 ft. It is an idyllic mountain resortcommunity and a major destination foryear-round recreation. Fishing, boating,hiking, and camping are abundantlyavailable during the warmer seasons,while skiing and other snow relatedactivities are a real favorite of winterenthusiasts.

Big Bear was established as a localresort destination in 1884, afterconstruction of the first dam and thesubsequent establishment of a lakein a valley surrounded by picturesquemountain peaks. A larger capacity dam,impounding a 73,000 acre-ft lake, wasconstructed in 1912 and still standstoday.

History of the BridgeSan Bernardino County completed aconcrete highway bridge crossingthe dam to provide access directly tothe resorts from the San Bernardinovalley floor in 1924. The 351-ft-long,21-ft-wide bridge carried two lanes oftraffic with one narrow sidewalk. Thebridge comprised 12 spans of fourgirders each. The girders were haunchedconcrete T-beams resting atop archedribs attached to the face of the concretedam. The girder depth varied from 2.5

ft at the center of the spans to 3.5 ft atthe simply supported ends.

During the Great Depression, thehighway network crossing the San

profile BIG BEAR BRIDGE/ SAN BERNARDINO MOUNTAINS AT BIG BEAR LAKE, CALIFORNIABRIDGE DESIGN ENGINEER:California Department of Transportation, Sacramento, Calif.

PRIME CONTRACTOR:Flatiron West Inc., San Marcos, Calif.

CONCRETE SUPPLIER:Robertsons Ready Mix, Corona, Calif.

POST-TENSIONING CONTRACTOR:AVAR, Fremont, Calif.ABUTMENT BEARINGS:D.S. Brown, North Baltimore, Ohio

by Raymond W. Wolfe and Ali Asnaashari, California Department of Transportation,and Bill Jahn, city of Big Bear Lake

A TIME TO REPLACEConstructing a Safer Tomorrow

The Big Bear Bridge nears completion.

All photos and drawings: California Department of Transportation.



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. . . replacement [was] the only trueviable option.

Bernardino Mountains was transferredto the State of California. The highwaycrossing the dam was designated asState Route 18 (SR 18).

An Aged BridgeNearly 60 years after it was opened totraffic, widespread deterioration wasreported during an inspection and areplacement was deemed a highpriority. The report identified numerouslocations of concrete spal ls andcorroded reinforcing bars. The bearingpads at each of the dams arch spandrelshad suffered significant damage fromyears of deicing salts applied to thebridge deck. Temporary measures were

instituted while a replacement wasplanned.

Final ly, the configuration of thehighway at the bridge as well as thenarrow width of the structure playedan important role in its demise. Theorientation of the dam relative tothe approaching highway forcedtraffic to turn left at a stop sign justwest of the old bridge to remain onSR 18 toward their destination in BigBear. The narrow width among other

factors led to a Functionally Obsoleteclassification. The Sufficiency Ratingor overall health indicator of the bridgeas of March 2003 was 19.6 (out of100 possible), with ratings less than80 considered deficient. Key factors incomputing these values such as deckgeometry were such that they couldnot be enhanced through rehabilitation,leaving replacement as the only trueviable option.

Creating a DramaticDefining CommunityLandmarkDesigners worked closely with theappropriate regulatory agencies at thefederal, state, and local levels, as well

as the local communityto develop replacementalternatives. The bridger e p l a c e m e n t p r o j e c t

was required to meetboth federal Nat ionalEnvironmental ProtectionA c t a n d C a l i f o r n i aEnvironmental Quality Actenvironmental statutes.The final environmentaldocument, begun in 1984,was signed in 2007, withconstruction commencingin late 2008.

Several alternatives were

developed during theenvironmental phase of theproject, with environmentalimpacts including potentialm ine ra l po l l u t i on o fthe lake water from analignment directly overthe lake as well as generalaesthetic impacts. Thefinal alignment divertedsouth of the existing dam,creating a new bridgecrossing Bear Canyon.

This alignment afforded adramatic canvas to create asignature bridge capturingthe spirit of the communitywhile integrating with thesteep jagged ravine.

A ConcreteSolutionA 474-ft-long arch bridgewith two 237-ft equalspans of post-tensioned, cast-in-placeconcrete box girders now graces thepristine landscape, as if it were leapingfrom one rock face of the ravine tothe other effortlessly. The bridge is ona tangent alignment at Abutment 1,changing to a 501-ft-radius curved

alignment near Abutment 5. The profilegrade of the bridge is at 0.8% with a2% cross slope. The superstructure issupported on polytetrafluoroethylene(PTFE) spherical bearings at theabutments and two 6.5-ft frictionpendulum isolation bearings at the

POST-TENSIONED, CAST-IN-PLACE CONCRETE ARCH SUPPORTING CAST-IN-PLACE BOX GIRDER / CALIFORNIADEPARTMENT OF TRANSPORTATION, OWNER

SEISMIC ISOLATION BEARINGS:Earthquake Protection Systems, Vallejo, Calif.

BRIDGE DESCRIPTION: A 474-ft-long structure with two 237-ft equal spans of post-tensioned, cast-in-place concrete box girder. The 10-ft deep boxgirder superstructure rests on a cast-in-place concrete arch. The arch cross-section is hollow, trapezoidal in shape, with a depth that varies from 10 ft at

the crest to approximately 15.5 ft at the base. The arch splits into two legs that are combined at the crest with a width of 45 ft. Each leg is 22.5 ft wide atthe base.

BRIDGE CONSTRUCTION COST:$35.5 million

The belvedere or overlook permits pedestrians a vista of

the lake. The dam and existing bridge are at the left.



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crest of the arch. Each isolation bearingcarries 4600 kips and has a longitudinalmovement capacity of 18 in. Two 72-in.-diameter, cast-in-dril led-hole pilessupport each corner of the abutments.These piles along with isolation bearingsprovide the necessary lateral strengthrequired to meet the seismic demand ofthe bridge.

The exterior webs of the girders aresloped at a 45-degree angle. The12-in.-thick interior webs are spacedat 9-ft centers. The top slab thicknessis 8 in. and the soffit slab is 6 in.thick. The design concrete compressivestrength is 5000 psi. All of the topslab reinforcement including thereinforcement for the barrier railings isepoxy coated.

The superstructure is post-tensionedwith 4200 kips of force in each webfor a total jacking force of 33,600 kips.A typical group of tendons has three4-in.-diameter ducts and one 43/8-in.-diameter duct. The 4-in. ducts containtwenty-two, 0.6-in.-diameter strandswhile the 43/8-in. duct has twenty-seven,0.6-in.-diameter strands. All of the ductswere fully grouted after the structurewas stressed.

Cast-in-Place ArchThe arch consists of two cast-in-placereinforced concrete legs separated atthe two bases and connected at the

crest of the arch. The arch cross-section

is hollow and has a trapezoidal shapewith a depth that varies from 10 ft atthe crest to approximately 15.5 ft atthe base. From the crest, it splits intotwo legs. The top width of each legof the arch is 22.5 ft at the base and45 ft combined width at the crest.The bottom width of each leg varies.There are four circular continuousreinforcement cages at each corner of

each half of the arch connected with18-in.-thick reinforced concrete top andsoffit slabs and 24-in.-thick webs. Thespecified concrete compressive strengthof the arch ribs was 3500 psi.

Seismic SafetyThe new bridge meets current seismicdesign criteria, lending a dramaticimprovement over the old structure.The Big Bear valley and surroundinglandscape is underlain with numerousfaults, including the ominous southbranch of the San Andreas Fault.The latter is presumed capable of amaximum credible event exceeding8.0MMS on the Richter scale. The otherlesser faults in the region may produceevents ranging from 6.0 to 7.5MMS.

Capacity, Operations, andMaintenanceThe new structure provides one 12-ftlane in each direction for traffic, aright-turn lane for westbound trafficheading onto SR 38 around the westside of Big Bear Lake, and two 10-ft

shoulders. The shoulders facilitate snow

removal by accommodating temporarysnow storage. A black-tinted polyesterconcrete deck overlay reduces icingpotential, thus minimizing the need for

damaging deicing chemicals.

A Community IdentifierThe new bridge is a testament to a roadwell traveled. When visitors ascend SR18 and reach the entrance of Big BearLake, the site of the new bridge tellsthem they have arrived, that they havemade it to Southern Californias onlyfour-season resort. The opening of thebridge was accomplished with greatfanfare on June 24, 2011. The bridgehas created a resurgence of pride inthe local community as its aestheticallypleasing architecture is certain to winaccolades and draw tourists and bridgeenthusiasts for the next century tothis pristine alpine resort community.The timing of its opening during aprotracted recession is certain to helprevive the local economy.__________

Raymond W. Wolfe is the District 8

director for the California Department of

Transportation in San Bernardino, Calif.,

managing operations throughout San

Bernardino and Riverside Counties; AliAsnaashari is a senior bridge engineer

for the California Department of

Transportation in Sacramento, Calif., and

the designer of record for the bridge; Bill

Jahn is the mayor of Big Bear Lake, Calif.


Falsework and forming for the arches.

The Big Bear Dam and existing bridge.

A dramaticimprovement over theold structure.

The Big Bear valley . . . is underlain with

numerous faults, including the south branch of theSan Andreas Fault.



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http://www.flatironcorp.com/designbuild


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The Dulles Corridor Metrorail Project,a two-phase, 23-mile extension of theexisting 106-mile Metro rail system,will connect the nations capital,Tysons Corner, and Washington DullesInternational Airport. Construction ofPhase 1, the first 11.6 miles, is nearly50% complete. It will include fivestations and multiple auxiliary powerfacilities and environmental controls.

One of the projects biggest challengeshas been working in and around thisheavily congested area. Work sitesare limited and narrow, mostly in themedians of the areas most traveledthoroughfares where traffic moves justfeet away. The safety of the travelingpublic and our employees is the top

priority of this project, said GeorgeMorschauser, executive director for theprojects design-build contractor.

Project OrientationPhase 1 features nearly 3 miles of aerialguideway. The rest of the alignment willrun at-grade except for a 2400-ft-longtunnel between two of the stations.There are three guideway sections inthis new alignment: O-1, TysonsEast, and Tysons West.

The O-1 begins at the eastern end ofthe project, where the new line will split

from the existing Metro Orange Line.It features two parallel, 1600-ft-longguideways that fly over I-66, a majorinterstate highway.

The other two guideways, Tysons Eastand Tysons West, are precast segmentalconcrete box girder bridges constructedusing highly-visible trussesmassivemachines that are unlike anything mostof the areas traveling public has everseen.

The congestion of Tysons Corner wasa main reason to use trusses for themajority of the guideway work insteadof ground-based cranes. Wereusing overhead trusses because theyare the most efficient method, said

Shawn MacCormack, the projects taskmanager for aerial structures. They areideal in dense urban environments likeTysons Corner because they use a top-down construction method and havelittle impact on the traveling public.

Traveling from east to west, once overthe O-1 guideway, the rail line willdescend to grade level for about 2 milesin the median of the Dulles ConnectorRoad (Route 267). Then, the Tysons Eastguideway begins, crossing over into

Tysons Corner, and into the first of thefour Tysons Corner stations. From there,

the rail will continue at an elevatedlevel, ascend to its highest pointapproximately 55 ftover the eight-lane I-495 Capital Beltway and thendescend into the second station wherethe rail line briefly goes underground.

The alignment resurfaces in the medianof Route 7 at the third station, which ispartially underground. From there, theTysons West guideway begins, runningfor about a mile and through the fourthstation. One final flyover takes theguideway westward into the median ofthe airport access highway, descendingto grade for the rest of the alignment.The fifth station is located approximately4 miles west of Tysons Corner.

How Theyre BuiltThe Tysons East and West guidewaysare being constructed using more than2700 precast concrete segments thatare fabricated in an off-site facility onDulles Airport property. All segmentsare match cast. The short-line castingmethod is used for the typical mainguideway segments and the shallowerstation segments use the long-linecasting method.

The segmental box is approximately 7

ft 6 in. wide by 8 ft deep, with a topflange approximately 16 ft wide for the

profile DULLES CORRIDOR METRORAIL PROJECT AERIAL GUIDEWAYS/ TYSONS CORNER,VIRGINIASUBSTRUCTURE DESIGN ENGINEER:Bechtel, Vienna, Va.

SUPERSTRUCTURE DESIGN ENGINEER:Corven Engineering Inc., Tallahassee, Fla.

CONSTRUCTION ENGINEER AND ERECTION TRUSSES MANUFACTURER:Deal, Pozzuolo del Friuli, Italy

PRIME CONTRACTOR:Dulles Transit Partners, Vienna, Va.a team of Bechtel and URS

CONCRETE SUPPLIER:DuBROOK Concrete Inc., Chantilly, Va.

PRECASTER:Rizzani de Eccher USA, Bay Harbor Is lands, Fla.

by Shea Daughertyand Chris Jennions,Dulles Transit Partners

The Dulles Corridor MetrorailProject Connecting the Nations Capital with its International Airport

An aerial view of the Tysons East Guideway and the

truss that has helped construct it. This guideway took

about 18 months to complete and is more than a mile in

length. Photo: Chris Jennions.



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typical guideway sections. The boxeschange to 7 ft wide by 5 ft deep witha 16-ft-wide top flange through thestations, where the spans are about50% shorter. Guideway spans haveslightly thinner webs and slabs at 9 in.thick, while station segment webs andslabs are 10 in. thick.

Segments are trucked one-by-one totheir locations and hoisted into placeby the truss, where their match-castfaces are coated with epoxy, joined

together, and aligned. Segments areapproximately 10 ft long dependingon the radius of the alignment at that

location. Span lengths are generallydictated by the availability of ground forlocating the cast-in-place concrete piers,but where support is required in a road,straddle bents are constructed to avoidpermanent road diversions.

Support piers across the project varyin both footprint and height, rangingfrom 10 ft tall atop hills in the middleof an intersection cloverleaf to 55 fttall between two road bridges. In plan,most piers are rectangular with roundedcorners. Plan dimensions range from 6by 7 ft to 7 by 12 ft.

ConcreteSpecified concrete compressive strengthfor the columns and pier caps is 5000psi. The concrete strength is increasedwhere the substructure pier caps requirepost-tensioning due to their spanlengths; in these cases, the concretestrength requirement is 6000 psi.

Column and pier cap concrete includesa calcium nitrite corrosion inhibitorto protect the reinforcement fromcorrosion from deicing salts from roadsplash.

Concrete compressive strengths for theprecast segments range from 6000 to

8500 psi depending on their location.Both simple spans of roughly 130 ftand station spans have used 6000 psi,while the larger spans and balancedcantilever structures have required 8500psi. The mixes use ground-granulatedblast-furnace slag as a supplementalcementitious material.

Concrete maturity meters were usedfor the in-place strength of the cast-in-place substructure concrete wherepost tensioning was not required. Thisenabled the aerial crews to strip bothcolumn and pier cap formwork systemsearlier and reuse them elsewhere. Theclient approved the use of these metersfor stripping formwork, but not forverification of strength prior to post-tensioning. Curing compound was usedon fresh concrete when the formworkwas stripped before 7 days or lessthan 70% of the design strength wasachieved.

THREE MILES OF AERIAL GUIDEWAY THAT INCORPORATES FOUR DIFFERENT TYPES OF BRIDGE CONSTRUCTION /METROPOLITAN WASHINGTON AIRPORTS AUTHORITY, OWNER

POST-TENSIONING MATERIALS:VSL, Hanover, Md.

FORMWORK SUPPLIER:Symons of Dayton Superior, Des Plaines, Ill.

EXPANSION JOINT SUPPLIER:D.S. Brown, North Baltimore, Ohio

BEARING SUPPLIER:R.J. Watson, Amherst, N.Y.

GUIDEWAY DESCRIPTION: AASHTO precast, prestressed concrete box beams and steel plate girders, all with cast-in-place concrete decks;

segmental concrete box girders erected using both span-by-span and balanced cantilever methods built on cast-in-place concrete substructures

BRIDGE CONSTRUCTION COST:Approximately $170 million

A completed span in a span-by-span

construction area showing the cross

section of the guideway girder. Photo:

Chris Jennions.

The Tysons East Guideway as it curves westward toward Tysons Corner. Photo: Shea Daugherty.



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Post-TensioningPost-tensioning is used throughout theproject. In the stations, it is used in thesubstructure pier caps, straddle bents,and precast concrete mezzanine beams.

The precast concrete box beams in theO-1 guideway use 1-in.-diameterlateral post-tensioning bars at sixlocations in each span. The standarddesign of the segmental concrete boxgirders for locations both inside andoutside the stations contains six tendonsper span. With minor exceptions, thesecomprise four 19-strand tendons at 750kips each, and two 15-strand tendonsat 600 kips eachtotaling 4200 kips ofpost-tensioning in each span. Tendonsin the longest cast-in-place concrete

straddle bents use up to 31 strands.All post-tensioning strands are 0.6 in.diameter.

Grout for the post-tensioning ducts isproduced from one of two dedicatedmobile grout trailers. Each trailercontains a storage area for the groutand water, and the colloidal mixer, anda shelter area for the workers. Grouting

operations are done in accordance withstandard American Segmental BridgeInstitute practices.

The steepest grade is 4% at the

I-495 crossing, and almost none ofthe guideways is perfectly level, withthe exception of the stations. Thedecks and segments do not have anysuperelevation because the concrete railplinth, which is cast on the deck aftererection, provides this slope.

For safety reasons, bridge constructionis not allowed over active roadways,so a large amount of the work is beingdone overnight. This time constrainton the aerial team required intense

planning and coordination with theprojects maintenance of traffic team,as well as the Virginia Department ofTransportation (VDOT) and the projectowner.

Phase 1 construction has about a yearand a half to completion. The aerialguideways are scheduled for completionby May 2012. Once the system is turnedover to Metro, approximately 6 monthsof pre-revenue testing and integrationwith the existing system will occur, withthe first new riders boarding by the endof 2013.

__________

Shea Daugherty is construction

communications manager and Chris

Jennions is aerial lead field engineer, both

with Dulles Transit Partners in Vienna, Va.


A completed span has been post-tensioned together before being placed in its final

position in the Tysons East Guideway alignment. Photo: Chris Jennions.

Guideways by the Numbers

O-1 Guideway Two parallel, 1600-ft-long

guideways in the median ofInterstate 66 and the Dulles

Connector Road (Route 267) 23, 88-ft-long spans with 48-in. by

48-in. AASHTO box beams 16 spans with steel plate girders All decks are 9-in.-thick cast-in-

place concrete

Tysons East Guideway Two aerial stations 6178 lin. ft of segmental guideway

along the northern shoulder ofRoute 123, a major roadway inNorthern Virginia

75 spans, including five balancedcantilever spans and three precast,prestressed AASHTO box beamspans with cast-in-place concretedecks

1333 lin. ft of station guideway Three segmental erection trusses

operating concurrently Typical span-by-span length of 130

ft with balanced cantilever spansup to 174 ft. Station spans 66 ftlong

Tysons West Guideway One aerial station 5715 lin. ft of segmental guideway

along the median of Route 7, amajor Northern Virginia highway

55 spans, including three balancedcantilever

600 lin. ft of station guideway Two segmental operations working

concurrently

Upon completing a span, the truss prepares to launch to the next pier on the Tysons East

Guideway. Photo: Igor Scherbakov.



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http://www.pci.org/


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Just outside the tiny community of Echo,in Summit County, Utah, thousands ofmotorists drive by on I-80 every day. Inthis area, I-80 is a smooth, easy routeaportion of one of the longest interstatehighways in the country carrying peopleand products coast-to-coast for 2900

miles.

Two deteriorating bridges on I-80 inthis area threatened to shut downthis important corridor as the UtahDepartment of Transportation (UDOT)needed to replace the structures. Theagency estimated that any disruption toI-80 would detour the high volume ofinterstate truck traffic for 90 miles.

UDOT is recognized as a leaderin innovative accelerated bridgeconstruction (ABC). They challenged theconsulting and construction industryto find a way to minimize impact tothe traveling public as part of thereplacement of the I-80 bridges over

Echo Dam Road. The agency stipulatedthat the design-build team must removeexisting bridges and approach rampsand construct new bridges within 135calendar days after the notice to proceed.Additionally, the closure of I-80 at EchoDam Road was limited to 16 hours. To

receive the full incentive, the road neededto be open to traffic in less than 11 hours.The contract also stipulated incentive/disincentive pay for every 15 minutes thatI-80 was opened or closed as measuredagainst the allowable time window.

The design-build (D-B) contract wasawarded in April 2009. The team thendeveloped the first project in the UnitedStates to move a bridge span intoplace, including the approach slabs, injust a matter of hours using hydraul icrams and slide rails. This resulted inanother new first for UDOT and theirinnovative methods for ABC, and for acost of approximately 60% of the statesestimate.

Design BasicsThe original three-span, I-80 twinbridges over Echo Dam Road wereapproximately 40 ft wide and 101 ftlong including fill slopes under theapproach spans that rested on stubabutments. The span lengths were 30.5,

44, and 26.5 ft.

The new twin bridges are each 44 ft10 in. wide with a single 80-ft-longmain span and 25-ft-long approachslabs at either end. The approach slabsare designed to span their full

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