Precast Concrete Associationof New York, Inc. 706 Quaker Lane, Delanson, New York 12053 Tel: 518-895-8352 Facs: 518-895-2329 Email: pcany@aol.com Web: www.pcany.org

Carl Buchman, PE: Exec DirectorMary Ellen Yankosky: Admin DirectorEdward Hourigan, PE: Tech DirectorHarold Nelson, PE: Newsletter Editor

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2003 ASBI Designand Constructionseminar July 21/22at Newark airport

This year, the 2003 ASBI, "Design andConstruction of Segmental Concrete BridgesSeminar" will be held on July 21-22 in theMarriott Hotel at the Newark InternationalAirport in New Jersey. The seminar is co-sponsored by the New Jersey Department ofTransportation.

ASBI is the American Segmental BridgeInstitute which was founded in 1989 to pro-vide a forum for owners, designers, contrac-tors and suppliers to refine the design andconstruction, and advance the quality anduse of concrete segmental bridges.

The seminar program includes presenta-tions on the following;

Applications and AdvantagesAnalysis and DesignTime Dependent AffectsAASHTO Guide SpecificationsSpan by Span BridgesPrecast Cantilever BridgesCast-in-place Cantilever BridgesCable Stayed BridgesSpecial ApplicationsAASHTO-LRFD DesignGrouting TechnologyDurability, Speed and Life Cycle Cost

A number of ASBI Committees are active indevelopment of design and construction speci-fications for segmental bridges. A PCI-ASBIJoint Committee Developed "AASHTO-PCI-ASBI Segmental Box Girder Standards forSpan-by-Span and Balanced Cantilever Con-struction."

Additional details of the seminar are avail-able on the ASBI website at www.asbi-assoc.org. Registration for the seminar maybe made with ASBI by phone at 602-997-9965. The cost is $250 for TransportationOfficials and $450 for Non-Members. Reser-vations for the Marriott may be made byphone at 973-623-0006. ❏

First segmental viaducts openedfor northbound traffic on BostonCentral Artery/Tunnel project

The first precast segmental viaducts andinterchange ramps were opened for north-bound traffic on the Central Artery/Tunnel(CA/T) project in Boston this winter markinganother milestone for a project that has beenunder construction since 1991. The newstructures are part of a major interchange forI-90/I-93 and provide access for traffic fromthe underground artery tunnel to the newcable stayed Zakim Bunker Hill Bridge.

Segmental viaducts and interchangeramps, some with radii as tight at 200', havebeen used extensively on the project. Whenthe sixth and final contract with segmentalstructures is complete for the total project inlate 2004, almost 4,000 segments will havebeen incorporated in the CA/T.

A project review on the American Segmen-tal Bridge Institute (ASBI) website notes thereare 10 viaducts on the I-90/I-93 contract.They are parallel, above or below I-93 North-bound and comprise frontage roads, mainlinelanes and various turning ramps within theinterchange.

Photo taken in October '02, during erection with an overhead gantry crane shows segmental ramps onthe complex I-90/I-93 interchange in Boston. photo by Unistress

On this contract alone, a total of 1062precast segments were cast by UnistressCorp at their plant in Pittsfield, MA, and truckedto the jobsite. The segment lengths variedbetween 7.5' and 11' and weighed between35 and 55 tons each. They were match-castusing a casting machine. Unistress used fourmachines, one for the end segments and onefor each of the three segment types. Thecasting cycle was one segment per day permachine for the typical segments and onesegment per five days for the end segments.Job credits are as follows;

Owner: Massachusetts Turnpike AuthorityManagement Consultant:

Bechtel/Parsons BrinkerhoffDesign of Concrete Viaducts:

DMJM + HarrisGeneral Contractor:

Slattery, Interbeton, J F White, and PeriniConstruction Engineering:

Parsons Bridge and TunnelPrecaster: Unistress Corp

See story on page 2 for information onother contracts of the project. ❏

PRECAST CONCRETE ASSOCIATION OF NEW YORK, INC. July 2003 Volume 14, No 7

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PRECAST CONCRETE ASSOCIATION OF NEW YORK July 2003 MONTHLY NEWSLETTER Page 2

Segmental box girder standards forspan-by-span or balanced cantileverdesign from AASHTO-PCI-ASBI comm

Segmental box girder standards for span-by-span or balanced cantilever bridges areavailable in a report that was published by ajoint committee of AASHTO, PCI and ASBI inthe late 90s. The standards are recommendedfor spans from 30.5 to 61.0 m (100' to 150') forspan-by-span design, 30.5 to 61.0 m (100' to200') for balanced cantilever design, and deckwidths from 8.55 to 13.65 m (28' to 45').

The standard sections are available indepths of 1800, 2100, 2400, 2700, and 3000mm. The balanced sections have thicker top,bottom and web dimensions to allow for higherprestress forces that are required with bal-anced design. Shear key details for bulk-heads on each segment are also included.

Post-tensioning detailsPost-tensioning details are dependent on a

number of factors including the type of design,required post-tensioning forces, and size ofthe tendons. Tendons can be internal, whichare placed inside the segment webs or slabsor external, which are placed inside the seg-ment void. Some designs on the CA/T projectused both internal and external tendons.Access and erection conditions will determinewhether the design will be a balanced cantile-ver or span-by-span design.

The photo above, is taken inside the voidof a span-by-span section of ramp, duringpost-tensioning of the span. It shows tempo-rary post-tensioning bars (top corners andcenter of bottom slab) used for anchoring andalignment of segments during erection. It alsoshows deviation blocks (bottom corner of theslab) that will receive the final external post-tensioning. These tendons will extend from

Inside the void of a segmental ramp on CA/T project in Boston. photo by CA/T

the pier segment at one end, into a deviationblock in the void, thru a portion of the bottomslab, exit back into the void from a seconddeviation block, and finally terminate at theopposite end pier segment. Internal tendonsare totally encased in concrete.

Miscelaneous detailsTemporary tendons on the project have

been typically 1.375" Dywidag post-tension-ing bars. Final post-tensioning tendons havebeen made up from varrying numbers of 0.6"diam strand with Dywidag anchorages. Thestandards also include specifications for con-crete, rebar, grouting, epoxy joining of seg-ments and shop drawings. ❏

JFK, BQE & CA/Tconfirm plusses ofsegmental design

Three recent projects, here in the North-east, have confirmed the plusses or advan-tages of precast segmental design for com-plex urban sites. They are the JFK Airportlight rail guideway in New York City, theBrooklyn Queens Expressway (BQE) rampalso in New York City and the Central ArteryTunnel (CA/T) project in Boston.

Selection of segmental design for all threeprojects was based on the flexibility of seg-mental to meet complex site constraints, theadvantages of top down construction to solvetraffic and access problems at the site, andfinally the long term durability of concrete.

Here is a summary of the projects;

JFK Light Rail Guideway:5,195 segmentsPrecaster: Bayshore Concrete Products

BQE Connector Ramp:278 segmentsPrecaster: The Fort Miller Co

I-90/I-93 Interchange & I-93 NB, (A4) CA/T:1062 segmentsPrecaster: Unistress Corp

I-93 Viaducts and Ramps, (B1) CA/T:1535 segmentsPrecaster: Sanford Precast

I-93 Southbound I-90 Mainline, (C1) CA/T:430 segmentsPrecaster: Unistress Corp

I-93/I-90 SB Viaducts & Ramps, (C4) CA/T:200 segmentsPrecaster: Unistress Corp

I-93/I-90 Interchange at Albany St, (C2) CA/T:510 segmentsPrecaster: Unistress Corp

Demolition and Ramp SA-CN, CA/T:170 segmentsPrecaster: Unistress Corp ❏

Curvature (some radii as tight as 200') is shown for interchange ramp on CA/T. photo by CA/T

PRECAST CONCRETE ASSOCIATION OF NEW YORK July 2003 MONTHLY NEWSLETTER Page 3

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Elaborate construction engineering,key to precasting and erection ofsegmental work on the Central Artery

Elaborate construction engineering hasbeen key to the installation of precast seg-mental interchange ramps on the CentralArtery/Tunnel project in Boston. Complicatedramp geometry has been common with verti-cal and horizontal curves and superelevation.Spans for ramps have ranged from 100' to200', with horizontal curve radii from 200' to6,500'. In some locations, multi level rampsare supported by straddle bents. Even morecomplicated have been the erection schemesnecessitated by limited access for erectionequipment, interference of existing utilities,active rail tracks and highways, and the closeproximity of other structures.

Span by span and balanced cantileveredschemes have been employed with segmentsset by crane or rolled into position. In thephoto above, segments for a balanced canti-lever section were set by crane on one (far)side and rolled into position on the opposing(near) side. The temporary bents on the nearside spanned four active tracks for commutertrains entering South Station. Shoring adja-cent to the pier head, and visible in the photo,provides stability for the balanced cantileversection until it is complete.

Developing geometry controlExternal loads are considered in the geom-

etry control used for casting segments. Thecontrol is determined by a phased analysis ofthe erection scheme including initial camber,deflection of the erection equipment, and the

Photo shows balanced cantilevered erection on the Central Artery Project in Boston with segmentsrolled into position from a side inaccessible to a lifting crane. photo by Parsons

final profile of the span. In typical matchcasting procedures, the previous casting foreach casting setup is used as a bulkhead forthe current cast. The previous cast can thenbe adjusted vertically and horizontally toachieve the required three dimensional orien-tation required.

The adjustments are made using a fixedtheodolite oriented with the casting machineor form. Measurements are based on eleva-tions and alignment to the top of bolts andhairpins precisely set in the top of each seg-ment. Elevation checks, to the same boltsand hairpins, are made in the field as theerection proceeds, and the segments may beadjusted with jacks or devices incorporatedinto the erection equipment.

Six contracts on projectConstruction engineering for all of the seg-

mental interchange ramps has been providedby Parsons Bridge and Tunnel Group withoffices in Essex CT. Their work has includedconstruction analysis, integrated shop draw-ings, erection equipment and falsework de-sign and geometry control for the segments.The interchange ramps are part of six con-tracts on the CA/T project which will have atotal contract value in excess of $950 millionwhen the project is complete. The first via-ducts and interchange ramps to be opened totraffic are described in the story on page 1.The size and breakdown of the contracts isnoted in another story on page 2. ❏

Performance ofsegmental andcable stayedbridges in Europe

Segmental and cable stayed bridges werebeing built in Europe in the 1950s, and some10 years later in the United States. A reportfrom the Federal Highway Administration(FHWA), issued as FHWA-PL-01-019, is acomprehensive account of the technology ofsegmental and cable stayed bridges in fourcountries including Switzerland, Germany,Denmark and France.

Problems eliminated thrunew codes and practices

The report notes that performance prob-lems in Europe, from the 1960s and 1970shave been eliminated through new codes andpractices. Corrosion of prestressing tendonsor reinforcing steel is attributed to poor qualitygrouting of tendons or honeycombed con-crete allowing water, oxygen and chlorides toenter. European policy is to use protectiveoverlays on all types of construction and thisseems to be working.

More stringent controls and practices arebeing used to insure that ducts are sealed andfree of voids. The report notes that proce-dures are similar to specifications being rec-ommended by the Post-Tensioning Institute(PTI), American Segmental Bridge Institute(ASBI), and the Florida Department of Trans-portation (FDOT). The ASBI Design andConstruction Seminar to be held in Newark,NJ will include a presentation on "GroutingTechnology." See the story on page 1.

Commitment to effectivemaintenance, repair & up-keep

There is a greater commitment to imple-menting effective maintenance, repair andup-keep of bridges in Europe, even thoughinspection and condition assessments of ex-isting structures are made in a similar mannerto the US practice.

Europeans are satisfied with their segmen-tal and cable stayed bridges. A worldwidesurvey of 17,612 post-tensioned bridges con-ducted by the Danes notes that 351 (only 2%)have durability problems due to corrosion inthe tendons. Therefore with appropriate at-tention to grouting procedures, they expectsegmental bridges will serve well into theforeseeable future.

The report was authored by a team ofengineers from FHWA, Texas DOT, Califor-nia DOT, Florida DOT, TY Lin International,Parsons, HNTB Corporation and Figg Engi-neering. Further information is available atwww.international.fhwa.dot.gov. ❏

July 2003 PCANY MONTHLY NEWSLETTER Page 4

Producer Member Companies:AFCO Precast, Middle Island, NY 11953A & R Conc Specialties, New Windsor, NY 12550Bayshore Conc Prod, Cape Charles, VA 23310Binghamton Precast Supply, Binghamton, NY 13901Blakeslee Prestress, Branford, CT 06405Carrara & Sons, Middlebury, VT 05753Coastal Pipeline Products, Calverton, NY 11933William E. Dailey, Shaftsbury, VT 05262The Fort Miller Co, Schuylerville, NY 12871Hanson Pipe and Products, Pottstown, PA 19464Jefferson Concrete, Watertown, NY 13601Kistner Conc Products, East Pembroke, NY 14056Oldcastle Precast, Manchester, NY 14504Oldcastle Precast, South Bethlehem, NY 12161Riefler Concrete Products, Hamburg, NY 14075Roman Stone Construction Co, Bay Shore, NY 11706Rotondo Precast, Avon, CT 06001Schuylkill Products, Cresona, PA 17929Unistress Corp., Pittsfield, MA 01201LC Whitford Co., Wellsville, NY 14895

Associate Member Companies:Advanced Testing, West Stockbridge, MA 01266A-Lok Products, Tullytown, PA 19007Amcrete Products, Newburgh, NY 12550Concrete Prod Solutions, Houston, TX 77084Concrete Sealants, Royersford, PA 19468Con/Span Bridge Systems, Dayton, OH 45420Cresset Chemical Co, Weston, OH 43569Dayton Richmond Corp, Collinsville, CT 06022Engineered Wire Prod, Upper Sandusky, OH 43351GNR Technology, Sauquoit, NY 13456W R Grace, Cambridge, MA 02140Hail Mary Rubber Co, Warrington, PA 18976Helser Industries, Tualatin, OR 97062Henry Co Sealants, Houston, TX 77020H & H Hulls, Hudson, NY 12534Insteel Wire Products, Blairstown, NJ 07825International Precast Supply, Haverill, MA 01838The James Co, Guilford, CT 06437JVI Inc, Pittsfield, MA 01201M A Industries, Peachtree City, GA 30269Master Builders-Preco, Lexington, KY 40509Mixer Systems, Pewaukee, WI 53072NPC Inc, Milford, NH 03055Parsons Diamond Prod, W Hartford, CT 06110A L Patterson, Fallsington, PA 19054Polylok Inc, Yalesville, CT 06492Press-Seal Gasket, Fort Wayne IN 46852Sika Chemical, Trenton, NJ 08619Spillman Company, Columbus, OH 43207Splice Sleeve N A, Bonita Springs, FL 34134Struc Reinf Products, Hazleton, PA 18201Syracuse Castings Sales Corp, Cicero, NY 13039USF Fabrication, Hialeah, FL 33018

Professional Member Firms:Abate Engineers, Buffalo, NY 14225Baker Engineering, Elmsford, NY 10523Barton & Loguidice, Syracuse, NY 13220Bergmann Associates, Rochester, NY 14614A L Blades, Hornell, NY 14843Clough Harbour & Assoc, Albany, NY 12205Consulting Engrs Group, Mt Prospect, IL 60056John S Deerkoski & Assoc, Warwick, NY 10990Delta Engineers, Binghamton, NY 13901DiDonato Associates, Buffalo, NY 14224Finley McNary Engineers, Essex, CT 06426FRA Engineering, Henrietta, NY 14467Goodkind & O'Dea, Rochester, NY 14604Harza Northeast, Utica, NY 13501Hunt Engineers & Archs, Horseheads, NY 14845Integrated Engineering, Bellingham, WA 98228LaBella Associates PC, Rochester, NY 14614LEAP Assoc International, Tampa, FL 16007Maser Consulting, West Nyack, NY 10994McFarland Johnson, Binghamton, NY 13902O'Neill Consulting, Spring Lake Hts, NJ 07762PCI-New England, Belmont, MA 02178Pratt & Huth, Williamsville, NY 14221Prymus Consulting, Bayport, NY 11705Ryan Biggs Associates, Troy, NY 12180A H Sample Engineers, Ottsville, PA 18942R Samsel Engineers, Henrietta, NY 14467Simpson Gumpertz & Heger, Arlington, MA 02174Spectra Engineering, Latham, NY 12110Edward Watts Engrs, Williamsville, NY 14221Wilbur Smith Assoc, Latham, NY 12110H Wilden Assoc, Allentown, PA 18106

PCANY Officers, Directors and StaffPresident: Jay Abbey, Binghamton PrecastSecretary: Scott Harrigan, The Fort Miller CoTreasurer: Rick Martel, Unistress CorpAssociate Director: Andy LaMothe, A L PattersonProf Director: Scott Chenet, Barton & LaGuidiceImmediate Past Pres: Tony Mazzeo, Oldcastle PrecastExecutive Director: Carl BuchmanAdministrative Director: Mary Ellen YankowskyTechnical Director: Ed HouriganNewsletter Editor: Harold Nelson

Precast Concrete Associationof New York, Inc.706 Quaker LaneDelanson, NY 12053

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Evolution, one segment at a time:views by the editor

We continue to be fascinated with the evo-lution of segmental technology as evidencedby work covered this month in our newsletter.Precasting and erection on the CA/T in par-ticular, have been most innovative. The projectsets a new standard for solving problems of acongested urban site and advancing the evo-lution of segmental technology.

An article that will appear in the 3rd Quarterissue of PB Network Magazine entitled "USPrecast Segmental Casting Yards" by ArthurPalmer would suggest there is more to come.The article notes the high cost and a castinglife of 400-600 uses for individual forms.Greater use of AASHTO/PCI/ASBI standardsections would reduce these costs. Furthersavings are foreseen with material evolution,including the use of welded wire fabric, highperformance concrete (HPC), self-compact-ing concrete (SCC), and a new generation ofSCC with polycarboxylates.

The article also envisions geometric align-ment of forms controlled by computerized hy-

draulic systems to quickly align the matchcastpiece and casting form. A surveyor could usetotal station and peanut prisms on controlpoints to speed the process. A Global Posi-tioning System (GPS) could be developed forthe casting yard or plant as an alternate to thepresent system for control of each castingmachine.

Design/Build is also noted and will add tothe evolution of segmental bridges by utilizingskills of the entire project team. Outsourcingthe casting to a precaster has significant riskmanagement benefits. National plant certifi-cation programs with either the Precast/Pre-stressed Concrete Institute (PCI) or NationalPrecast Concrete Association (NPCA) offer alevel of expertise in design standards, qualitycontrol and production capability that can bemodified for casting segments.

It's neat to think of the evolution of segmen-tal technology, the congested urban site, andcurving, superelevated bridges being castone segment at a time. ❏