Innovated Technology for Accelerated Construction of Bridge and Embankment Foundations in Europe

7/30/2019 Innovated Technology for Accelerated Construction of Bridge and Embankment Foundations in Europe

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Technical Report Documentation Page1. Report No.

FHWA-PL-03-0142. Government Accession No. 3. Recipients Catalog No.

4. Title and Subtitle

Innovative Technology for Accelerated Construction of Bridge and

Embankment Foundations in Europe

5. Report Date

September 2003

6. Performing Organization Code

7. Author(s)Chris Dumas, Sam Mansukhani, Dr. Ali Porbaha, Richard D. Short,Randy R. Cannon, Kevin W. McLain, Dr. Sastry Putcha, Alan Macnab, Maung

Myint Lwin, Thomas W. Pelnik III, Dr. Dan A. Brown, Dr. Barry R. Christopher

8. Performing Organization Report No.

9. Performing Organization Name and Address

American Trade Initiatives

P.O. Box 8228

Alexandria, VA 22306-8228

10. Work Unit No.(TRAIS)

11. Contract or Grant No.

DTFH61-99-C-0005

12. Sponsoring Agency Name and Address

Office of International Programs

Office of Policy

Federal Highway Administration

U.S. Department of Transportation

13. Type of Report and Period Covered

14. Sponsoring Agency Code

15. Supplementary Notes

FHWA COTR: Hana Maier, Office of International Programs

16. AbstractIn June 2002 the scan team met in Europe with technical and industry leaders representing Belgium, Germany, Italy, the

Netherlands, Sweden, and the United Kingdom to identify and evaluate innovative European technologies in accelerated

construction of bridge and embankment foundations. The scan team also explored opportunities for cooperative research

and development and implementation of accelerated construction technology.

The scan team identified and evaluated 30 technologies and 15 processes with the potential for accelerating construction

in the areas of bridge foundation systems, equipment, and ground improvement methods; embankment deep foundation

systems, equipment, and ground improvement methods; embankment mat foundation systems and equipment;embankment construction equipment and methods; innovative earth-retention systems; and processes and implementation

methods. The report provides tabular summaries of these technologies along with a relative ranking in terms of anticipated

improvements in construction time, cost, and quality.

The overall goal of the scan trip is to implement technologies of best practice in the United States. With this objective

clearly in mind, team members developed an implementation ranking. The technologies that were selected for immediate

implementation action are:

Column-supported embankments

Continuous flight auger and cased secant pile bridge foundations

Automated computer installation control and installation documentation

Self-compacting concrete

17. Key Words

Construction, geotechnical, bridge, foundations,

embankments, continuous flight auger, self-compacting

concrete, geotextile, column-supported embankment

18. Distribution Statement

No restrictions. This document is available to the public from

the

Office of International Programs

FHWA-HPIP, Room 3325

US Dept. of Transportation

Washington, DC 20590

[email protected]

www.international.fhwa.dot.gov19. Security Classif. (of this report)

Unclassified20. Security Classif. (of this page)

Unclassified21. No. of Pages

9022. Price

Free

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized


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Innovat ive Technol ogy f orAccel er at ed Const r uct ion of

Br idge and Embankment Foundat ionsIn Eur ope

a nd

Am erican Trad e Initiatives, Inc.

&

LGB & Asso ciates, Inc.

for the

Fed eral High w ay Ad m inistra tion (FHWA)U.S. Dep a rtm en t of Tra nsp orta tion

a nd

The A m erican Associat ion of State H ighw ay a ndTransportation Officials

a nd

The Na tional Coop erat ive Highw ay Research Program(Pan el 20- 36 )

of the Tran spo rta tion Resea rch Boa rd

Pr epar ed by t he Scanni ng Team:

S EP T EM B E R 2 0 0 3

Chris Dumas

FHWA

Sam M ansukhani

FHWA

Dr. Ali Porbah a

CALTRANS

Richard D. Short

Kleinfelder, Inc.

Randy R. Cannon

Sou th Carol ina DOT

Kevin W. M cLa in

M issour i DOT

Dr. Sastry Putcha

Florida DOT

Alan M acnab

Condon-Johnson &

Assoc. Inc.

M aung M yint Lwin

FHWA

Thom as W. Pelnik III

Virginia DO T

Dr. Da n A. Brown

Aub urn Universi ty

Dr. Barry R. Christopher

Consult ing Engineer


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FHWA INTERNATIONAL TECHNOLOGY

EXCHANGE PROGRAMS

The Feder al H ighway Admin istr at ions (FHWA) int ern at iona l program s focus onmeeting the growing demands of its partners at the Federal, State, and local levels foraccess to inform at ion on st at e-of-th e-art technology and t he best pra ctices usedworldwide. While FHWA is consider ed a world leader in highway t ra nsport at ion, th e

domestic highway comm un ity is int erest ed in th e advan ced technologies beingdeveloped by oth er coun tr ies, as well as inn ovative organizat iona l an d fina ncingtechniques used by FHWAs international counterparts.

The International Technology Scanning Program accesses and evaluates foreigntechnologies a nd innovations t ha t could significan tly benefit U.S. highwaytr an sporta tion system s. Access t o foreign inn ovat ions is st ren gthen ed by U.S.participation in the technical committees of international highway organizations andthrough bilateral technical exchange agreements with selected nations. The programis und ert ak en coopera tively with t he Amer ican Associat ion of Sta te H ighway andTransportation Officials and its Select Committee on International Activities, and the

Transportation Research Boards National Cooperative Highway Research Program(Panel 20-36), the pr ivate sector, and academ ia.

FH WA an d its pa rt ner s jointly deter mine pr iority t opic ar eas. Team s of specialists inth e specific ar eas of expertise being investigated a re form ed an d sent to countr ieswher e significan t a dvances an d innovations ha ve been ma de in technology,management practices, organizational structure, program delivery, and financing.Team s usu ally include Federal a nd St at e highway officials, private sector an dindustry association representatives, and members of the academic community.

FH WA has organ ized more tha n 50of these r eviews an d disseminated resultsna tionwide. Topics ha ve included pa vement s, bridge const ru ction a nd m aint ena nce,

contr acting, inter modal tra nsport, organizationa l ma na gement, winter roadma inten an ce, safety, int elligent t ra nsport at ion syst ems, plan ning, an d policy. Findingsare recommended for follow-up with further research and pilot or demonstrationprojects to verify adaptability to the United States. Information about the scanfindings an d results of pilot pr ogram s ar e then disseminat ed nat ionally to Sta te an dlocal highway transportation officials and the private sector for implementation.

This progra m has resulted in significan t impr ovements a nd sa vings in r oad pr ogramtechnologies an d pra ctices th roughout the United St ates, particularly in t he a reas ofstru ctur es, pavements, safety, and winter r oad m ainten ance. J oint r esearch an dtechnology-sharing projects have also been launched with international counterparts,

fur ther conserving resources and a dvancing the st at e of the ar t.For a complete list of Int ern at iona l Techn ology Scann ing topics, and to order freecopies of the r eport s, please see pa ges iii-iv.

Website: www.international.fhwa.dot.govEm ail: int ern at iona [email protected]


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FHWFHWFHWFHWFHWA I NTERNAA I NTERNAA I NTERNAA I NTERNAA I NTERNATIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTS

Internat ional Techno logy Scanning Program:Bringing Global Innovat ions to U.S. Highways

Infrastructure

Geotechnical En gineering Pra ctices in Can ada an d Eu ropeGeotechn ologySoil N ailingInt ern at iona l Cont ra ct Administra tion Techn iques for Qua lity En ha ncement -CATQEST

Cont ra ct Administ ra tion: Techn ology and Pr actice in E ur ope

Pavements

Eu ropean Asphalt TechnologyEu ropean Concrete Techn ologySouth African Pavement Techn ologyHighway/Commercial Vehicle InteractionRecycled Mat erials in Eur opean H ighway En vironmen tsPavemen t P reser vation Technology in F ra nce, Sout h Africa, and Austr alia

Bridges

Eur opean Bridge Stru cturesAsian Bridge Str ucturesBridge Maint ena nce CoatingsEur opean Pra ctices for Bridge Scour and Strea m In stability Count ermeasu resAdvan ced Composites in Bridges in Eu rope and J apa nSteel Bridge Fabrication Technologies in E ur ope and J apa nPerform an ce of Concrete Segm ent al an d Cable-Sta yed Bridges in Eu rope

Planning and Environment

Eu ropean Int erm odal Pr ogra ms: Plan ning, Policy, and TechnologyNat iona l Travel SurveysRecycled Materials in Eu ropean H ighway E nvironmen tsGeomet ric Design Pr actices for Eur opean RoadsSusta inable Tran sporta tion Pr actices in EuropeWildlife Habita t Conn ectivity Across E ur opean H ighwaysEu ropean Right-of-Way an d Ut ilities Best P ra ctices

Safety

Pedestrian a nd Bicycle Safety in England, German y and the N etherlan dsSpeed Man agemen t a nd E nforcement Technology: Eu rope & Austr aliaSafety Mana gement Pr actices in Ja pan, Austr alia, an d New ZealandRoad Safety AuditsFina l ReportRoad Safety AuditsCase St udiesIn novat ive Tra ffic Contr ol Techn ology & Pr actice in Eur opeCommercial Vehicle Sa fety Technology & Pr act ice in E ur opeMethods a nd P rocedur es to Reduce Motorist Delays in E ur opean Work ZonesMan aging and Orga nizing Compr ehens ive Highway Safety in Eur ope

Operat ions

Advan ced Tra nsport at ion TechnologyEu ropean Tra ffic MonitoringTraffic Man agement and Traveler Informa tion SystemsEu ropean Wint er Service Techn ologySnowbreak Forest Book Highway Snowstorm Count ermeasu re Ma nua l (Translated fromJapa nese)Eu ropean Road Light ing Techn ologiesFreight Tran sporta tion: The Eu ropean MarketTraveler In forma tion Systems in Eur ope


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Policy & Inform a tion

Em erging Models for Delivering Tran sporta tion Program s an d ServicesAcquiring H ighway Tran sporta tion Inform at ion from AbroadHan dbookAcquiring H ighway Tra nsport at ion I nform at ion from AbroadFinal ReportIntern ational Guide to H ighway Tran sporta tion Informa tionEu ropean Pr actices in Tra nsport at ion Workforce Developmen t

All publ icat ions are avai lable o n the internet at ww w.internat ional .fhwa.dot .gov


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Abbr eviat ions and Acr onyms

AASHTO Amer ican Associat ion of Sta te an d Highway Tra nsport at ion OfficialsADECO Analysis of Controlled Deforma tion

ADSC Internat ional Associat ion of Foundat ion Dri ll ingCDW Con tin uou s dia ph ra gm wa ll

CFA Cont inuous fligh t augerCIP Cast-in -placeCPT Cone penetra t ion test

CSP Cased secan t pileCS V S oil st a biliza t ion wit h ver t ica l colu m nsDOT Depa rt ment of Tr anspor ta tion

EC European CommissionEU European UnionFH WA Fede ra l H igh way Ad min is tr a t ion

F WD Fa llin g weigh t deflect om et er

GE C Geot ext ile-en ca sed colu mn sGRP Gla ss-r ein for ced pla st icIBRC Inn ova t ive Br id ge Res ea rch an d Con st ru ct ionLRF D Loa d a n d r esist a nt fa ct or design

MSE Mech an ica lly st abilized ea rt hNDM Nat iona l Deep Mixing Coopera t ive Research programQA Quality assu rance

QC Quality cont rolRPUM Reinforced Protect ive Umbre lla Method

SASW Spect r a l an a lys is of s ur face waves

SCC Self-com pa ct in g cem en tTRB Tr an spor ta tion Resea rch Bu rea u

UK United Kingdom


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CONTENTSEXECUTIVE SUM M ARY ................................................................................................. ix

PURPOSE ................................................................................................................................... ix

M ETH OD .................................................................................................................................... ix

OVERVIEW OF TECHNOLOGIES AN D PRACTICES OBSERVED .................. .................. .............. ix

FINDINGS ....................................................................................................................................x

Bridge Foundations.............................................................................................................x

Em b a nk m en t Fo u nd a tion s ................................................................................................ xi

Em b a nkm en t Con stru ctio n ................................................................................................ xi

Ea rth -Rete n tion Syste m s ................................................................................................... xii

Proce sse s a n d Ap p ro a ch es ............................................................................................. xii

RECOM M ENDATION S.............................................................................................................. xiii

IM PLEM ENTATION ................................................................................................................... xiv

1. OVERVIEW .................................................................................................................. 1

BACKGROU ND ........................................................................................................................... 1

PURPOSE ................................................................................................................................... 2

M ETHODOLOGY OF STUDY ...................................................................................................... 3

ORGAN IZATION OF REPORT ..................................................................................................... 5

2 . SWEDEN, FINLAND , AND U NITED KING DO M .......................................................... 6

IDENTIFIED ACCELERATED CON STRUCTION TECH NOLOGIES .................. .................. .............. 7

LESSON S LEARNED: ACCELERATED CON STRUCTION M ETHOD S................. ............... ............. 8

LESSONS LEARNED: PREFABRICATED TECH NOLOGIES...... ..... .... ..... .... ..... ..... .... ..... .... ..... ..... ... 13

LESSON S LEARNED: STATUS OF LIM IT STATE DESIGN ..... ..... .... ..... .... ..... ..... .... ..... .... ..... ..... .... .. 13

3 . GERM ANY ............................................................................................................... 14

IDENTIFIED ACCELERATED CON STRUCTION TECH NOLOGIES ................. .................. .............. 16

LESSON S LEARNED: ACCELERATED CON STRUCTION M ETHOD S................ ................ ............ 16

LESSONS LEARNED: PREFABRICATED TECH NOLOGIES...... ..... .... ..... .... ..... ..... .... ..... .... ..... ..... ... 19

LESSON S LEARNED: STATUS OF LIM IT STATE DESIGN ............... ................. ................ ............. 2 0

4 . ITALY ........................................................................................................................ 2 1

IDENTIFIED ACCELERATED CON STRUCTION TECH NOLOGIES ................. .................. ............. 2 4LESSON S LEARNED: ACCELERATED CON STRUCTION M ETHOD S................ ................ ........... 2 4

LESSON S LEARNED: PREFABRICATED TECH NOLOGIES .................. ................. ................. ....... 3 0

LESSON S LEARNED: STATUS OF LIM IT STATE DESIGN ............... ................. ................ ............. 3 0

5 . BELGIUM ................................................................................................................. 3 1

IDENTIFIED ACCELERATED CON STRUCTION TECH NOLOGIES ................. .................. ............. 3 3

LESSON S LEARNED: ACCELERATED CON STRUCTION M ETHOD S................ ................ ........... 3 3


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LESSON S LEARNED: PREFABRICATED TECH NOLOGIES ............... .................. ................. ......... 3 5

LESSON S LEARNED: STATUS OF LIM IT STATE DESIGN ............... ................. ................. ............ 3 5

6 . M AJOR FINDIN GS .................................................................................................. 3 6

BRIDGE FOU ND ATIONS........................................................................................................... 37

EM BAN KM ENT FOU NDATIONS .............................................................................................. 37EM BAN KM ENT CON STRU CTION ............................................................................................ 3 8

EARTH-RETEN TION SYSTEM S ................. .................. ................. ................. ................. ............ 3 8

PROCESSES AND APPROA CH ES ................. ................. ................. ................ ................. ......... 3 8

7. CO NCLUSION S AND RECOM M END ATION S FOR IM PLEM ENTATION ...................... 4 5

CON CLUSION S ........................................................................................................................ 4 5

IM PLEM ENTATION ................................................................................................................... 4 5

APPEND IX A: AM PLIFYING QU ESTIONS ..................................................................... 4 7

APPEND IX B: IND IVIDU ALS CON TACTED BY THE STU DY TEAM ......... .......... ......... ..... 5 0

APPEND IX C: BIBLIOGRAPH Y ..................................................................................... 5 6

APPEND IX D: SCAN TEAM CON TACT DATA AND BIOG RAPHIC INFORM ATION ......... 6 3

APPEND IX E: EN 19 9 7 EUROCO DE 7: GEOTECH NICAL DESIGN ......... .......... ......... ....... 6 8

LIST OF TABLES

Ta b le 1. Geo tech nica l Eng ine ering Sca n Tea m M em b ers. .................................................. 4

Ta b le 2 . Ho st Rep resen ta tives. ............................................................................................... 4Tab le 3. Techno logies an d Processes for Accelerated Con struction of Bridge

a n d Em b a n km en t Fou nd a tion s ............................................................................. 3 6

Tab le 4 . Br idg e Found at ion System s, Equipm ent , and Ground Im provem entM ethods for Accelerated Construct ion an d Reha bi l itat ion onPoo r Sub g ra d es ...................................................................................................... 4 0

Tab le 5 . Em ba nkm ent Found at ion System s, Equipm ent , and Ground Im provem entM ethod s for A ccelerated Construction on Poo r Sub gra de s. ..... .. .. .. .. .. .. .. .. .. .. .. .. .. 41

Tab le 6 . Em ba nkm ent M at Found at ion System s and Equipm ent for AcceleratedConstruction on Poo r Sub g rad es or over Deep Fou nd ation s. ..... .. .. .. .. .. .. .. .. .. .. .. . 42

Tab le 7. Em ba nkm ent Const ruction Equipm ent and M ethod s for AcceleratedCon stru ctio n ............................................................................................................ 4 3

Tab le 8. Inno vat ive Earth-Retent ion System s for Accelerated Con struction a ndReh a b ilita tion . ......................................................................................................... 4 4


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LIST OF FIGURES

Figure 1. Exam p le o f rap id b r idge rep lacement show ing t ranspor t o f newb ridg e w ith sp ecia lized lift (from Belgia n p rese nta tion). ..................................... xi

Figu re 2. Euro SoilStab p roject on de ep so il m ixing (from BRE p resen tation) ..... .. .. .. .. .. .. .. . 2

Figu re 3. Sub ject m atter p resen tations w ere often pro vided . ..... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 5

Figu re 4. Tra ne b erg Brid g e reco nstru ction p roject .............................................................. 6Figu re 5. Ho llow, dri lled- in soil na ils are used to sta bil ize a slop e ..... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 7

Figure 6 . Si te vis i t to a rock tunne l port ion of the Southern Link roadco n stru ctio n p ro ject ................................................................................................ 7

Fig ur e 7. M a ss sta b iliza tion tech niq ue ................................................................................. 9

Figu re 8. Field visit to M esche d e roa dw ay slop e stab ilization p roject ..... .. .. .. .. .. .. .. .. .. .. .. .. 15

Fig ur e 9. Gre en -fa ced w a ll site visit .................................................................................... 15

Figu re 10. Site visit to th e Betuw e ra ilw a y line (in the Ne therla nd s). ................................... 15

Figu re 11. Jacking a b ridg e into fina l po sition (from Germ an p resen tation). ... .. .. .. .. .. .. .. .. 20

Fig ur e 12. Th e Soilm ec fa ctor y tou r. ....................................................................................... 2 1

Figure 13. Secan t pi les used for excavat ion an d w al l construct ion in the Trevipa rk(from the TREVI Gro u p p re sen tatio n ).................................................................... 2 1

Figure 14. CFA pi le supp orted em ba nkm ent project for the high-spe ed rai l projectsho w ing : (a ) CFA p ile insta llation a nd (b ) insta lled CFA p iles ............................ 22

Figu re 15. Turin sub w ay p roject site visit sho w ing: (a ) station exca vation a nd (b)con tinuo us d iap hra g m w a ll co nstru ction. ......................................................... 22

Figure 16. Tur in sub w ay g rout ing project si te vis it show ing: (a) grout ing an d(b ) g ro u t p u m p sta tion . ....................................................................................... 2 3

Figure 17. Schem atic of the A DECO me thodo logy presented by theIm p re g ilo Gro u p ................................................................................................... 2 3

Figu re 18. Site visit to the hig h-sp eed rail l ine pro ject nea r An tw erp . ..... .. .. .. .. .. .. .. .. .. .. .. .. .. .3 1

Figure 19. Sound ba r rier const ruction us ing cap ped deb r is and contam inatedso il m o un d ............................................................................................................. 3 1

Figu re 2 0. Screw p ile test site a t the Belg ian Buildin g Rese a rch Institute (BBRI). .............. 3 2

Figure 2 1. Br idg e can al p roject vis i t in Strepy sho w ing: (a) cana l br idge und ercon struction a nd (b ) a eria l view inclu d ing b oa t eleva tor. ................................. 32


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EXECUTIVE SUMMARY

PURPOSE

In J un e 2002, th e Federa l Highway Administ ra tion (FH WA), in a joint effort with t heAmerican Associat ion of Sta te Highway a nd Tr an sporta tion Officials (AASHTO),organized a geotechn ical engineer ing scan tour of Eu rope. Its p ur pose was t o ident ifyand evaluate innovative European technology for accelerated construction andrehabilitation of bridge and embankment foundations. The scan team also exploredopportunities for cooperative research and development and implementation ofaccelerated construction technology.

The scan tea m eva luat ed th e following technologies for a ccelerat ed const ru ction a nd/or reha bilitation:

Bridge foundation systems, equipment, and ground improvement meth ods.

Embankm ent deep foundation systems, equipment, and ground improvementmethods.

Embankment mat foundat ion sys tems, equipment .

Embankment cons t ruct ion equipment and methods.

Innovat ive ear th -re ten t ion sys tems.

Processes and implementa t ion methods.

M ETHO D

The geotechnical scan team members included both geotechnical a nd stru ctur al(bridge design) engineers representing Federal, State, academic, and private industrysectors. Team mem bers were invited t o par ticipat e on t he bas is of their positions a sleaders in the development and implementation of new technologies. The team metwith technical an d industr y leaders in Sweden, Finland, th e United Kingdom,Germ an y, Italy, and Belgium t o acquire det ailed design an d const ru ction inform at ionfor p ossible applicat ion in th e Un ited St at es. To effectively evalua te t he equ ipmentand techniques that may be used for accelerating construction, approximately 50percent of th e scan t eam s activities were devoted t o viewing ph ysical dem onst ra tionsof th e t echn ologies an d m eth odologies in Sweden, th e Net her land s, Germ an y, Italy,an d Belgium . Team mem bers a lso condu cted inter views, including case st udybriefings, with contr actors and equipment m an ufactur ers.

OVERVIEW OF TECH NOLOGIES AN D PRACTICES OBSERVED

The t eam identified 30 technologies an d up to 15 processes th at offer a potentia l foraccelerating construction and rehabilitation of bridge and embankment foundations.Man y of the technologies a lso offer a potentia l for cost savings a nd, in a ma jority ofthe cases, an improvement in the quality over current practice. This report includescomplete t ables with a relat ive ra nkin g of all th e technologies in t erm s of ant icipat edimpr ovemen ts in const ru ction t ime, cost, an d qua lity (located in chapt er 6). Thetechnologies th at offer t he grea test potentia l for su ccess in t erm s of const ru ctionexpediency and ea se of implem ent at ion a re su mm ar ized in t he following sections.


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EXECUTIVE SUMMARY

Team members also gained insight on other, related construction practices in Europethat may benefit U.S. practice. In several European countries, the emphasis is onma inta ining tr affic dur ing const ru ction, which often dicta tes t he const ru ctionprocedures and has led to innovations in parallel bridge construction. Team membersreviewed severa l projects in wh ich t he n ew bridge was const ru cted adjacent t o th e oldbridge, foundation support was improved under the old bridge while maintaining

tr affic, then th e new br idge was m oved into fina l position by a specialized tr ucktr an sporter (as shown in t he exam ple in figure 1) or by sliding. Tra ffic disru ption washeld to a m inimu m, for exam ple, less tha n 72 hour s in two cases. Anoth er em pha sis ison th e redu ction of noise (also a key issue in t he U nited S ta tes), which drove the u seof some of th e techn ologies identified in th e scan tour. Public relat ions plays a nimporta nt role, and sometim es includes offers to relocate families durin g theconst ru ction period.

FINDINGS

The overall goal of th e scan t rip is t o implem ent technologies of best pr actice in t heUnited St at es. With t his perspective in m ind, the tea m identified Eu ropeantechnologies an d met hods to accelerat e const ru ction a nd devised new ways in wh ichth ese technologies could be applied in both th e Unit ed Sta tes a nd E ur ope. Thisprocess r esulted in a vast an d broad a rr ay of cross-applicat ions of techn ologies,met hods, an d pr ocesses tha t wa s so lar ge and complex th at concise and effectivecomm un icat ion of th e scan tea ms findings became a ma jor concern . After m uchthought a nd discussion, th e team strongly agreed tha t t he findings should bepresented in an easy-to-use ta bular form at tha t is organized ar ound end user s needs.The goal was t o devise tables su ch th at engineers could ent er with a sp ecific need,and quickly see a list of applicable scan findings along with important supplementalinformation about the use of a specific technology for their specific need. The followingpar agraph s sum ma rize selected t echnologies highlighted by the t eam as h aving ahigh potent ial for a ccelerat ing constr uction wh ile maint ainin g or im proving both costan d qua lity.

Bridge Found a tions

For bridge foundation construction, the standard of practice in the United States forpoor t o mar ginal foun dat ion conditions is dr iven piles or drilled sha fts. Becau se ofqua lity contr ol/qua lity assu ra nce (QC/QA) problems with au ger-cast piling, auger-castor cont inuous flight a uger (CFA) piles a re r ar ely used in U.S. bridge const ru ction. CFApiles with a utomat ed compu ter contr ol for monitoring insta llation an d a utomat ed QCwould appear to offer a ra pid alterna tive to the current pra ctice tha t could be easily

implemented. Bored cased secant pile (CSP) techniques with automated computercontr ol should also be evaluated a s an altern at e accelera ted m ethod tha t can provideboth bridge support a nd excavation support in cut situ at ions. For lar ge projects withdifficult drilling conditions a nd/or tight spaces, the u se of a diaph ra gm wallconst ru cted with a Hydro-MillTM offers a ra pid const ru ction met hod with low noisean d low vibra tions th at could also be used to support lar ge loads.


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EXECUTIVE SUMMARY

Em ba nkm ent Founda tions

For em ban km ent foun dat ion const ru ction over soft, compr essible soils, th e Eu ropean s

ar e using column-supported embank ment s t o accelera te constr uction instead of theclassical meth od of using su rchar ge with or without wick drain s. The a pproach ispreferr ed because of its mu ch sh ort er const ru ction t ime, simplicity of QC,environmental friendliness, and its nonimpact on the performance of existingroadways, rail lines, and buildings.

Alth ough t his is a familiar t echnology in t he Un ited Sta tes, it is often associated withhigh cost an d difficult access pr oblems. However, advan ces in pile a nd geosynth eticbridging platform technology ident ified on t his tour convinced the scan t eam th atcolumn-supported embank ment s is a n att ra ctive method for accelera ted constr uctionan d should be explored a s a viable altern at ive for most soft gr oun d pr ojects.

The t eam also identified new t echn ology for t he st abilizat ion of the u pper 10 to 16 ft(3 to 5 m) of soil ma ter ials th rough eith er m ass m ixing or ra pid impact compa ctiontha t m ay also hold some pr omise in constr ucting founda tion su pport ma ts with an dwithout deep foundation systems.

Embankment Construction

Severa l technologies evalua ted on th e tour offer the poten tial to accelerat e placementan d compa ction of fill for const ru ction of th e emba nk men t it self, while main ta ining orimpr oving cost a nd qu ality. Lightweight fills have been u sed in th e Unit ed Sta tes t o alimited extent to redu ce placement an d sur char ge time in soft soil conditions. Thefrequency of th is use in Eu rope appea rs t o be increa sing (it is almost rout ine).Expanding its u se in t he Un ited Sta tes sh ould increase availability an d decrease cost,making lightweight fills such as geofoam an attractive alternative to surcharge fills,an d also should accelera te const ru ction. The r at e of emba nkm ent const ru ction couldalso be significant ly increa sed th rough t he u se of high-energy impa ct, rollingcompactors and rapid impact hydraulic hammer compactors, both of which appear toprovide a mu ch great er depth of compa ction, allowing for placement of thicker fills.Another promising technology application is the use of instrumentation on thecompaction equipment to measure dynamic modulus in real time, which can be used

Figu re 1. Exa m ple of rap idbr idge rep lacement showing

transpo r t o f new br idge w i thspe cialized l i ft (from Belgian

presentation).


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EXECUTIVE SUMMARY

for improving compaction uniformity and effective compaction effort. Mostimporta nt ly, th e ability of inst ru men ted compa ction equipm ent to provide 100 percentQC coverage should a llow t he use of perform an ce-based appr oaches t o specificat ions,leading to the effective implementation of warrantees and guarantees for botheart hworks and pavements (as is curr ently the pr actice in Eu rope).

Ea rth-Retention System sRapid const ru ction a ltern at ives to convent iona l bridge reta ining wall constr uction(i.e., using sh eeting a nd shoring with cast-in-place walls) were ident ified th at could beeasily implement ed. These t echn ologies include bored CSP t echn iques an d cont inuousdiaph ra gm walls, both of which a re a pplicable for t he r eta ining wall as well as t hesupport of th e bridge. These m eth ods can p rovide consider able speed a nd cost sa vingswhere (1) access space is limited (widening projects); (2) sound walls will be attachedto th e top of th e ret ainin g wall; an d (3) difficult drilling is ant icipat ed. In a ddition,both met hods pr oduce low noise a nd low vibrat ions, which could significan tly increa setheir production because such equipment could be operated for a greater number ofhours dur ing a day th an conventiona l equipment.

Processes and Approa ches

The team agreed tha t th e scan tour findings with t he greatest potent ial foraccelerated construction are processes and approaches used in the development ofprojects or in pr oject cont rol. The comm on th eme am ong a ll of these processes issim plicity th rough sophistication.

Practically all of the equipment and construction methods employ real-timeau tomated installation contr ol an d documen ta tion. These systems m onitor, measur e,cont rol, an d docum ent critical a spects of the technology an d, ther eby, allow for ra pidconst ru ction without compr omising qua lity. In fact, in most cases t hey impr ove

qua lity. In addition to fast er inst allat ion, th ese technologies and m eth ods accelerat econstr uction by redu cing or eliminat ing QC methods tha t a re int rusive to theconstruction process. Another extremely important aspect of these methods is thatthey h ave allowed the realization an d implementa tion of rat ional perform ancespecifications an d warr an tee/guara ntee r equirements.

We also observed th e simplicity th rough sophistication appr oach being a pplied toconst ru ction ma ter ials. Specifically, one of th e m ost exciting finds of the tr ip was th ecommon usage of self-compacting concrete (SCC) in Sweden. SCC is not a newtechnology, but SCC r esear ch, developmen t, an d implemen ta tion to the h ighlyadva nced level of comm on usa ge is a n ew achievement .

By using a dvanced SCC t echnology, Sweden is a ble to pour concret e in in tr icat e form san d/or den se reinforcement situa tions significant ly fast er, using far fewer workers,an d sm aller pu mps, while still achieving sup erior qua lity. SCC should lead t o a longerlife via superior coverage of reinforcement and low permeability. It providessignifican t benefits when p ost t ension or other ductwork is presen t. Since vibrat ion isnot needed, ductwork cann ot be pus hed out of alignmen t or crush ed, ther eby avoidingcostly an d t ime-consu ming field r epair s. The scan tea m is working t o utilize SCC in


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EXECUTIVE SUMMARY

new ways n ot observed dur ing th e scan t rip (e.g., the u se of SCC in dr illed sha ftfoun dat ions in h igh seismic regions).

The scan t eam identified severa l other Eur opean Comm unity (EC) stan dard processestha t could lead t o impr ovements in both constr uction r at e and quality at a modera tecost , including:

Requiring the designer and th e contra ctor to have a QC/QA program modeledafter th e ISO 9000 ser ies process, providing m ore consistency in design an dconst ru ction qua lity.

Increasing requirements for computer aut omat ed equipment control and requiringgenerated data to be provided a s par t of the QC pr ogram , aut oma tically producingcomplete r eal-time report s of all dat a, resu lting in improved const ru ctionefficiency and essentially 100 percent QC.

The Germa n Federal H ighway Research Institu te (BASt) presented a process toevaluate which method would provide optimum acceleration considering the totalscope a nd in tegra tion with all pha ses of th e pr oject (i.e., how accelerat ed const ru ctionmet hods fit in with th e critical pa th for project completion). This pr ocess is deta iled inthis report and will be used by the team as a model to help agencies identifyopportunities and the optimum method for accelerated construction.

RECOM M END ATION S

The overall goal of th e scan t rip is t o implem ent technologies of best pr actice in t heUn ited Sta tes. With th is objective clearly in min d, team mem bers developed animplemen ta tion ra nkin g using th e following two-step process:

(1) The tea m as a whole reviewed and discussed each t echnology with r espect to its

potentia l for accelerat ing const ru ction.(2) Each t eam member selected t he two technologies for wh ich h e ha d th e str ongest

desire to champion implement ation.

The technologies that were selected for immediate implementation action are:

Colu mn -s u pp or t ed emban k men t

CFA and CSP br idge foundations

Automated computer instal lat ion control and installat ion documenta tion

Self-compact ing concrete

Man y of the other technologies ident ified in th e scan t our sh ow great promise, butsuccessful implemen ta tion requir es a cha mpion. In a ddition, given th e diversity of theteam members (contractor, consultant, Department of Transportation [DOT], Federal,geotechnical, and structural engineers), the ranking should be an excellent indicatorof th e accelera ted t echn ologies preferences of th e highway const ru ction comm un ity asa whole.


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The a bove list is not necessar ily a r an king of techn ologies with t he grea test technicalpotentia l for accelerat ing constr uction. Inst ead, it is a list of Eu ropean a ccelerat edconstruction technologies with the greatest potential for implementation in theUn ited Sta tes. This type of focused selection should ensur e th at our resour ces arefocused an d not dilut ed. Plan s for implemen ta tion of all potentia lly beneficialtechnologies ar e deta iled in th is report.

IM PLEM EN TATION

At the end of the tour, team members reviewed an implementation plan, whichcons isted of:

Pr esentat ions on new technologies, as identified in the body of this report , atengineering meetings.

Invited equipment demonstrat ions by manufacturers .

Cooperative efforts with European organizations.

Local efforts by team members to use the technologies within th eir organizationson demonstration projects.

A Scan Technology Implement at ion P lan t eam was organ ized to develop a requ est forseed fundin g to assist in t he im plement at ion effort s for specific, high-prioritytechnologies. The complete im plement at ion pr ogra m is deta iled in th is report.


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CHAPTERONEOVERVIEW

BACKGROUND

The int erst at e highway system is a key componen t t o the well-being of the U.S.economy. In r ecent years, however, th e Amer ican public has been subjected t o the

effects of an aging and det eriora ting highway system, while at the sam e time t hehighway system ha s seen significant increases in t ra ffic. The r esulting increa se incongestion impedes t he m obility of society an d a dds costs associat ed with th emovement of commer ce. Tra ffic disru ption dur ing const ru ction a nd m aint ena nce ofbridges an d str uctur es is now frequent ly resu lting in disru ptions to local economies,an d m otorists, far in excess of th e capital out lay for t he const ru ction activity itself.The compet ing problems of replacing an aging system an d add ing capa city, versu s th eeconomic an d safety requ iremen ts for m aint ainin g existing tr affic flow ha s creat ed afeedback amplification of the problem by significantly lengthening the constructionprocess. This in tu rn has resulted in a n even lar ger negative impact on motoristsafety and local economies.

It is clear th at th ese pr oblems will only accelerat e in t he coming decades. According tostatistics reported by the Federal Highway Administration (FHWA), approximately 14and 16 percent of the bridge inventory falls into the functional and structuraldeficient categories, respectively (Report to Con gress:1999 S tatu s of the Na tionsHighways, Bridges, a nd Transi t:Cond itions and Perform ance, pp. 6-17, Exhibit 6-13,May 2, 2000). Furthermore, States are experiencing increasing problems with thedeterioration and even failure of other highway structures, such as retaining walls,culvert s, sign bridges, an d light sta nda rds. In 1997, na tionwide bridge expenditur esrelated to system preservation and construction of new highway bridges were US$6.1billion and US$10.0 billion, respectively (Repor t to Congress: 1999 S tat usof N ations

Highways, Bridges, an d Transi t: Con dit ion s an d Perform ance, pp. 6-17, Exhibit 6-13,May 2, 2000).

Therefore, development and implementation of accelerated construction andreh abilitat ion t echn ology is imper at ive to th e long-term hea lth of th e U.S.infrast ru ctur e system an d economy. Recognition of accelerat ed const ru ction a s ana tiona l imperative is underscored by the recent Tran sport ation Research Boar d(TRB) Task Force AST60 Workshop Accelerating Opportunities for Innovation in theHighway In dust ry. The American Associat ion of Stat e Highway a nd Tra nsport at ionOfficials (AASHTO) also has a companion activity through the AASHTO TechnologyImplementation Group, which has selected high-speed construction as a potentialproduct a nd h as form ed Accelerat ed Constr uction Techn ology Team s t o advance itsimplementation.

Dra wing on E ur opean techn ology and expert ise in the a rea of high-speed constr uctioncan significan tly increa se th e pace of the developmen t a nd imp lement at ion pr ocessan d redu ce costs. Eur opes procur emen t pr ocess an d population density ha ve drivenforward and necessitated rapid innovation in accelerated construction. For example,ma ny of th e leading Eu ropean founda tion contr actors resea rch, develop, an d buildtheir own equipment to suit their specific needs and proprietary foundation system.In addition to speed of construction requirements, their technology addresses many


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CHAPTER ONE: OVERVIEW

issues t ha t ar e coming t o the forefront of U.S. highway const ru ctionlimited space,noise limitat ions, vibrat ion cont rol, and pollution.

Other ar eas of proven leadership in E urope include ra pid embankm ent constr uctionon soft soils. This issue is becoming pr ominent in th e Unit ed Sta tes, as demonst ra tedby the soft groun d problems at th e I-15 reconst ru ction pr oject in Sa lt Lak e City, Ut ah ,an d t he Woodrow Wilson Bridge (WWB) Pr oject in N orth ern Virginia. In th e case ofth e WWB pr oject, ground impr ovemen t costs ar e expected to exceed US$30 m illion.Europe has invested heavily in ground improvement technology and continues to doso. Cur ren tly, the E ur opean Commission is spending US$4 m illion t o fun d th eEu roSoilStab project, which consist s of 17 pa rt ner s from six coun tr ies (see figure 2).The indu str ial objective of the pr oject is t o provide th e Eu ropean const ru ctionindus tr y with compet itive const ru ction t echn iques, backed by guida nce document s fortheir use, to stabilize soft organic soils.

PURPOSE

The prima ry pur pose of the Eu ropean scan tour was t o discover an d evaluateinnovative Eur opean t echn ology for accelerat ed const ru ction a nd r eha bilitat ion ofbridge an d emba nk men t foun dat ions. The scan tea ms goal was t o ident ify successfuland most promising technologies that have potential for immediate application in theUnited Sta tes an d to tra nsfer t hese best pra ctices to the U.S. tr ansporta tion

comm un ity. Other funda men ta l objectives of th e scan included seeking outopport un ities for cooperat ive resear ch, development , an d implemen ta tion ofaccelerat ed const ru ction technology. The tour also provided a n opport un ity to obtaininformation on accelerated construction of the superstructure, such as usingprefabricated bridge structures and foundations. Acceleration of the superstructureconst ru ction is also part of th e cur ren t TRB and AASHT O initiatives on a ccelerat edconstruction. This information could be used to plan a future tour for a structuralengineerin g group. The tour gave the tea m t he opport un ity to follow up on th eEuropean experience in applying the limit state design methods in Eurocode 7, aprim ar y subject of a pr evious geotechnical engineerin g pra ctices tour in 1999.

Figu re 2 . Euro SoilStab pro ject ondee p so i l m ixing (from BREpresentation).


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M ETH OD OLOG Y OF STUD Y

The scope of th e scan t rip was to evalua te t he a pplicability of technology cur ren tlybeing used in Eu rope for a ccelerat ed constr uction. The t eam mem bers a ccomplishedsuch evalua tion th rough ph ysical dem onstr at ions of th e techn ology, int erviews, an dcase st udy br iefings. The t eam sought s pecific informa tion on:

New bridge and embankment foundat ion sys tems.

Foundation equipment a nd technology for a ccelerated construction a ndrehabilitation.

Innovative earth-retention systems for accelerated construction andrehabilitation.

Innovative technology for accelera ted ground improvement of bridge andembank ment founda tions.

The st udy t our provided a n opport un ity for face-to-face meet ings with k ey individua ls

who ar e r ecognized expert s on s pecific technologies an d indu str y leader s. Toeffectively evaluat e th e equipment an d techniques th at may be u sed for accelera tingconst ru ction, a pproximat ely 50 percent of the scan activities were devoted t o physicaldemonst ra tions of the technologies or met hodologies.

The geotechnical scan team members included both geotechnical a nd stru ctur al(bridge design) engineers representing Federal, State, academic, and private industrysectors, who ar e considered leaders in th e developmen t a nd/or imp lement at ion of newtechnologies. Table 1 presents the team members, their r epresenta tion on the scantea m, an d th eir a ffiliat ions. The t eam originally met in th e winter of 2001 to compile alist of basic amplifying questions on each of th e t opics of interest . The am plifyingquest ions, which wer e sent to each of th e coun tr ies prior t o the visits, ar e listed in

Appendix A.

The scan tea m selected which coun tr ies to visit on t he ba sis of their experien ce withimplemen ting t he technologies of int erest . A Desk Scan of innovative Eu ropean an dAsian activities in accelerated construction of bridge and embankment foundationswas performed to assist in the selection process. The team met with technical andindust ry leader s in Sweden, Germa ny, Italy, an d Belgium t o acquire det ailed designan d const ru ction inform at ion for possible applicat ion in t he Un ited St at es. Thesessions in Sweden included represent atives from F inland a nd the United Kingdom.The principal representatives from each country and their affiliations are shown inta ble 2. A complete list of th e na mes of all cont acts with th eir cont act inform at ion is

included in Appendix B.

The hosts extended a generous amount of hospitality and consideration in response tothe amplifying questions. In most countries, hosting agencies prepared an agenda ofexpert presenta tions, based on the quest ions t ha t h ad been forwarded to them inadvance. This presentation usually included briefings with contractors and equipmentma nufacturer s. In It aly, an equipment m anu facturer /contr actor a nd two inter na tiona lcontr acting firms served as h osts in thr ee separa te locations. In addition to thepresentations and roundtable discussion (figure 3), site visits were arranged to


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Tab le 1. Geotechnical Eng ineer ing Scan Tea m M em bers

N a m e Rep resen ta tion Org a n iza tio n

Chris Dum a s Tea m Co - lea d er FH WA, FH WA Ea stern Resou rce Cen terGeotechnical Eng ineer

Ra nd y R. Ca nno n Tea m Co - lea d er Sou th Ca ro lin a DOTAASHTO, Bridge Design Engineer

M a u ng M yin t Lw in FH WA Structu ra l Desig n Eng ineer FH WA Western Resou rce Cen ter

Sa m M a n sukh a n i FH WA Geo techn ica l En g in eer FH WA M id w estern Reso u rce Cen te r

Kevin W. M cLa in Sta te Geo tech n ica l Eng ineer M issou ri DOT

Th om as W. Pe ln ik, III Sta te Geo tech n ica l Eng in eer Virg in ia DOT

Dr. A li Po rb a h a Sta te N ew Tech no lo g ies a nd Resea rch Ca lifo rn ia DOT

Geotechnical Eng ineer

Dr. Sa stry Pu tch a Sta te Co nstru ctio n Ge ote ch nica l En gin ee r Flo rid a DOT

Dr. Da n A . Brow n Pro fesso r Geo tech n ica l En g in eering Au b urn U n iversity

A la n M acn a b The In terna tio na l Associa tion o f Con d on -Joh nso n & Associa tes Inc.Fou nd ation Dril ling (ADSC)

Rich a rd D. Sho rt The Deep Fo un d a tion s In stitu te Kle in fe ld er, Inc.

Dr. Ba rry Ch ristop h er Rep o rt Fa cilita to r Geo tech n ica l Eng inee ring Con su lta n t

Cou n try Prin cip a l Rep resen ta tive(s) A ffilia tion

Sw ed en M a tti H u usko ne Sw ed ish N a tiona l Roa dLen na rt Axe lson Ad m in istra tion (SN RA)

Germ a ny Fra u Ke lle rm a n n Germ a n Fed era l H ig hw a y Resea rch

Institute (BASt)

Ita ly Ste fa no Trevisa n i Th e Trevi Grou pCa rlo Crip p a Ro d io Corp o ra tio n

Ste fa no Ta lon e Im p reg ilo / G.G.F. S.p .A

Belg iu m Ga u th ier va n A lb oo m M in istry o f Tra n sp o rt, Flem ishGeotechnics Division

Tab le 2. Host Rep resen tatives


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demonstrate the application and performance of accelerated construction methods. Inall locations, the scan team shar ed inform ation with inter nat ional count erpar ts onU.S. policy, initiatives, and research activities to promote innovative geotechnicalengineering worldwide.

ORGANIZATION OF REPORT

The pr ima ry focus of the t our was t o ident ify and implemen t inn ovat ive techn ologiesof best pr actice for accelerat ed const ru ction of bridge an d emba nk men t foun dat ions.Accordin gly, the r eport pr ovides more deta ils on t hese su bjects th an on t he seconda rysubjects of evalua ting a nd exploring n ew or impr oved geotechnical products orpra ctices. The first s ections of th e report sum ma rize th e visits to each coun tr y. Thelast two sections pr esent th e tea ms findings, conclusions, an d r ecomm enda tions. The

findings section includes tables that an engineer can enter with a specific need andquickly see a list of applicable scan findings a long with im porta nt supplem ent alinformation about the use of a specific technology. Each host country provided asignifican t a mount of supporting litera tu re, and a bibliogra phy is included inAppendix C of the report . Appendix D cont ains cont act a nd biograp hical inform at ionon scan team members, and Appendix E provides a summ ar y of the development ,cont ent , and sta tu s of EN1997 Eu rocode 7: Geotechnical Design.

Figure 3. Subject matterpresentations were oftenprov ided.


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CHAPTERTWOSWEDEN, FINLAND, AND UNITED KINGDOM

The first scan sessions t ook pla ce in S weden on J un e 17 an d 18, 2002. The r eviewinvolved form al m eetings h eld at th e Solna r egional office of the S wedish Na tionalRoad Administrat ion (SNRA) with presenta tions by engineering a nd ma na gerialtr an sporta tion officials from th e SNRA; an engineer from Konsult; two Finnish

representatives from Finnish Road Enterprise; and a United Kingdom (U.K.)represent ative from th e resear ch group BRE, Centre for Gr ound Engineering andRemediation. Representatives from the private sector involved in the design,cont ra cting, an d const ru ction s ectors a lso joined in th e discussions, including Sk an skaTekn ik AB, Ska nsk a Ber g och Bro, Mbius, de neef Nort her n E ur ope, Her culesGrundlggning AB, and Tyrens. Presentations on the second day were held in theSdra Lnken (Southern Link) exhibition room and focused on the Southern LinkRoad Construction project, which had used several innovative features to maintaintr affic and to redu ce public inconvenience (e.g., noise issues). The tea m also ma defield visits t o severa l sites, including t he Tra neber g Bridge, a m ajor bridgereconst ru ction pr oject for wh ich vehicle an d ra il tra ffic ha s to be ma inta ined

th roughout th e pr oject (figur e 4); a soil na iling pr oject in wh ich self-drilling an dgrouting n ails ar e being used t o stabilize a slope (figure 5); an d severa l port ions of theSouth ern Link Road Constr uction pr oject in Stockh olm, including a soil an d rocktu nn el section (figure 6).

In S weden, severa l innovat ive technologies were pr esent ed, including m asssta bilization, in which cemen t, fly ash, or blast furn ace slag are m ixed with t he u pper10 t o 16 ft (3 to 5 m) of poor soils (e.g., peat , mu d, or soft clay) to provide a me th od foraccelerat ed ground impr ovement . Advan ces in deep soil mixing, an emer gingtechnology in the United States, were identified in terms of testing and equipment.Pr esentat ions highlighted the r esults of resear ch carr ied out under the E uropean

Un ion (EU)sponsored Eu roSoilStab pr oject for th e developmen t of design a ndconstruction methods to stabilize soft organic soils. In four of the countries involved inth e stu dy, full-scale field trials wer e completed, th ree u sing th e dry m eth od and one(in the United Kingdom) using the wet method. One of the contractors presented acost comparison of deep soil mixing and other soil improvement technologies.

Figure 4. Trane berg Bridge reconstruction project.


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CHAPTER TWO: SWEDEN, FINLAND, AND UNITED KINGDOM

IDENTIFIED ACCELERATED CONSTRUCTION TECHNOLOGIES

SCC is being used in Sweden for foun dat ion const ru ction a nd offers a poten tial t oredu ce noise genera ted from compa ction a s well as redu ced constr uction t ime. A wiretype r ock sa w is used to cut r ock in lieu of blastin g or line drilling, thereby limitingnoise and vibra tion an d speeding up const ru ction. Reduction of noise was emph asized

in several presentations. Public relations plays an important role, and sometimesincludes offers to relocat e families dur ing th e const ru ction per iod.

The u se of geotextile-encased column s, a Germ an technology, was intr oduced a s a fastmet hod of soft soil sta bilization (more det ails were pr ovided durin g the Ger ma n t our).A Dut ch met hod for const ru cting piled emban km ent s in very soft soils using plasticpipe filled with concret e was also briefly reviewed. In addit ion, developmen ts in t heuse of self-drilling and self-grouting micropiles and n ails were pr esent ed, and t he n ailtechnology was demonstrated during a site visit.

Figure 6. Site visit to a rock tunnel portion of the Southern Link road construction project.

Figure 5. Hol low , dr i lled- in soi l nai ls are used tostabi l ize a slop e.


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The United Kingdoms presentation reviewed the results of EuroSoilStab researchcarr ied out at BRE on deep mixing to sta bilize orga nic soils and h ow it can h elpaccelerat e const ru ction. In a ddition, relevant work to accelerat e const ru ction waspresented on ground tr eatm ent (surchar ging, dynam ic compa ction, and ra pid impactcompaction); soft ground foundation systems (vibro stone columns, vibro concretecolumns, and deep soil mixing); building on fill; and driveability of steel sheet piles.

The pr esent at ion concluded with a p review of an E U pr oject called TOPIC, which is inprogress, an d an EU pr oject a bout to sta rt on t he r e-use of foun dat ions. Inform at ionalso was pr esent ed on vibro-jet sheet p ile driving for r apid inst allat ion of tem porar ysheet ing. Inform at ion on adva ncement s in piles was offered, including on screw piles,which reportedly can be insta lled in one-th ird of th e time r equired for a uger-castpiles; piles tha t a re t ailored t o ma tch th e soil type; an d piles tha t m inimize concreterequirements. Literature was provided on high-energy compaction using impact type,noncircular rollers.

The Finnish presentation provided several valuable accelerated constructiontechnologies a nd complemen ta ry m eth odologies. Geotechnically, rap id au toma ted siteinvestigation m eth odology is being u sed in F inlan d. For example, new resist ivitytechnology is being used t o estima te wat er cont ent an d consolidat ion set tlemen t inexisting roadway embankments. With this technology and software, they are able todo a geophysical site investigat ion a long with prelimina ry design, time, and costcalculat ions in a few days inst ead of th e typical t ime of several m onths or more. Inaddit ion to being r apid, th is m eth odology quickly locates an d br ings pr oject focus/resources to bear upon areas of the most importance with respect to project timelines, costs, and performance objectives. Consequently, project site investigations anddesigns are significantly faster, less costly, more cost-effective to construct, and havelower probabilities for delays a nd claims dur ing th e t otal pr oject cycle.

Structurally, steel pipe piles are predominantly used in Finland to achieve rapid

insta llation, especially in a rea s with boulders. To complemen t t his ra pid appr oach,they have developed a direct connection design detail that attaches the pile directly toth e super str uctur e (steel, precast concret e, or cast-in-place bridge girders ). Thisingenious a pproach eliminat es th e pile cap, pier column s, and t he pier cap. Liter ally,th e constr uction of th e entir e subst ru ctur e, excluding th e piles, is elimina ted,resu lting in typical savings of between 10 a nd 15 per cent of the en tire br idge cost.

LESSON S LEARNED: ACCELERATED CON STRU CTION M ETHODS

The following section reviews th e a ccelerat ed const ru ction met hods ident ified inSweden, the United Kingdom, and Finland in relation to the amplifying questions.

Th e mass s tabi li za t ion technique was identified in Sweden a s a m ethod tha t sa vestime when compa red with preloading (see figure 7). The t echn ology cam e fromFinland about 10 years ago. In the mass stabilization technique, the upper 10 to 16 ft(3 to 5 m) of the soft su bgrade is m ixed with a cemen t, fly ash, or blast furn ace slagsta bilizing agent over th e entir e sur face ar ea of a pr oject. The st abilizing agent istypically applied at a ra te of 30 to 40 lb/ft2 (150 to 200 kg/m 2). At t his ra te,appr oxima tely 400 to 650 yd3 (300 to 500 m 3) of soft soil can be st abilized per day.Mass stabilization projects performed to date show that settlements develop rapidly


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in sta bilized peat a nd u nder lying un sta bilized soils. This met hod does requ irespecialized mixing equipmen t. The equipm ent is pat ent ed but t he pr ocess is not. Theavailability of equipmen t in t he Un ited Sta tes is un known, but it is possibly beingused in th e waste industr y.

For design, the properties of the stabilized mass are determined on the basis ofcorr elation with la b test dat a a nd local experience. The t echn ique ha s work ed well forpeat, mud, and soft clay, but as previously indicated, is only effective for the upper 10to 16 ft (3 to 5 m). Quality cont rol (QC) and qu ality as sur an ce (QA) are eva luat edth rough t he u se of convent iona l geotechnical field mea sur emen ts, including th e conepenetra tion test (CPT) to determine th e differences in permea bility properties a nd tocontr ol homogeneity in t he m ass st abilized peat; sta ndar d column penetra tion test(SPT); column vane t est; spectr al a na lysis of sur face waves (SASW) mea sur emen t;settlement; horizont al m ovement; and pore pressur e mea surem ents. The t echniquerequires little training. Average equipment contractors and inspectors can be taughtin a few days. Tra ining is required t o be able to determ ine th e am oun t of sta bilizationagent (cemen t, fly ash, blast furn ace slag) to mix, as well as t ypes, propert ies, an dvolume of agents.

Some safety issues a re a ssociated with t his techn ology, including tr an sport of cemen tfrom t he t ru ck to th e mixing machine. Using th e cur ren t t echn ology, cemen t cansprea d easily over th e site (e.g., windblown) and can cause bur ns t o th e skin a nd eyesas well as brea th ing problems. This t ra nsfer pr ocess will ha ve to be cha nged for U.S.implementation. In Sweden, the technology is contracted using a performance-basedspecification in wh ich th e cont ra ctor is responsible for th e per form an ce. Thecont ra ctor pr ovides a 5-year warr an ty. Performa nce is defined a s th e ability of the

system to limit settlement, as measured initially on the basis of lab tests on the soil-cement m ixtur e an d in th e long ter m on th e basis of field monitoring. The Un iversityof Lun d in Sweden is curr ent ly perform ing resea rch on t his t echn ology. Thetechnology has not been used in seismically active regions. Cold weath er a nd freezingsoil do not app ear to affect the a pplicat ion, at least in t he m ass st abilizat ion pr ojectsperform ed to dat e. The t her ma l conductivity of sta bilized peat is of an order a t wh ichit can be expected t o influen ce th e frost penet ra tion of th e whole road str uctur e. Themeasured thermal conductivity factors have been of an order of = 0.2 t o 0.6 W/Km,which corr esponds to ther ma l conductivity of na tu ra l peats (Car lsten, 1988;

Figure 7. M ass stab i lizat ion techn ique.


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Helenelun d, 1980). This insu latin g effect can be ta ken into account at th e frostdimensioning stage (Tielaitos, 1995).

Lime/cement co lumns (deep so i l mix ing) has been introduced in the Un itedSta tes; however, a significan t a moun t of developmen t work h as been perform ed inSweden. Much of the effort ha s gone int o QC an d QA, with some advan ces report ed tothe team on the rate of mixing and on in situ testing. Ongoing research on mixingener gy, i.e., relating st ren gth to mixing time (rota tions), was pr esent ed. Deep soilmixing uses specialized, paten ted equ ipment , much of which is r eadily available inthe United States. The process is not patented. A presentation was conducted on theanalysis of composite ground using a mean strength method. The EuroSoilStabConsortium, hea dquar tered a t th e Swedish Soil Stabilizat ion Research Center of theSwedish Geotechn ical In stitu te, has ongoing r esear ch pr ojects on t his su bject.

Self-compacting concrete (SCC; also known as self-consolidating concrete) wasidentified as a rapid construction technique currently being used and evaluated inSweden. Finnish an d Germa n r epresentat ives indicated t ha t t hey also ar e using SCCin br idge constr uction. SCC is a special, fine gr ain, fluid concret e mix (similar to a

mortar mix) that rapidly consolidates after placement to form a dense, high-strengthconcrete. Fluidifiers ar e used a s adm ixtur es to main ta in th e consist ency of the mix. Itha s significan t a dvan ta ges: no vibra tion is required, th e mix is very fluid, ther ebyflowing easily int o tight ar eas, and segregat ion is n ot a pr oblem. Main app licat ionshave been for structural components, such as facing units for tunnel linings, but thetechnology offers significan t potentia l for use in deep foun dat ions, such a s dr illedshafts. The technique does not require specialized equipment. Neither the equipmentnor th e process is patented, and the equipment is readily available in t he Un itedStates. SCC is contracted in Sweden on a unit cost basis. Means and methods ofapplications ar e based on specificat ion of mix design verification requir emen ts a ndsam pling and t esting of concrete.

Geotexti le-enc ased c olumn s (GEC) consist of insert ing cont inuous, seam less,high-stren gth geotextile tu bes into soft soil with a ma ndr el and filling the tu be withsan d (or fine gra vel) to form a column with a high bea ring capa city. The a pplicat ion issimilar to sand piles used in J apa n a nd st one columns, which ar e widely used in theUn ited Sta tes. It is suita ble for soft soils and wher e high bear ing capa city is desired.The meth od has been u sed for su pporting new roadway emban kment s and lar gepavemen t a rea s on 15 ft (5 m) of soft peat ma ter ial. Advan ta ges of this system overstone column s include: (1) the column is confined in su ch a way th at it does notintr ude int o th e soft soil; (2) a consisten t diam eter is main ta ined by the geotextiletu be; an d (3) impr oved shear capacity is provided by the high st ren gth of th e

geotextile an d t he confinemen t of th e sa nd or gravel. The geotextile also provides afilter to prevent th e int ru sion of fines (an d long-ter m loss of soil) while allowing waterto pa ss. This s ignifican tly impr oves dr aina ge an d a ccelerat es consolidat ion. Followingclassical consolidat ion t heory with dr aina ge improvements provided by th e column s,consolidat ion r at es on the order of 80 to 90 percent h ave been achieved with in th reemont hs. The technique a llows for r apid inst allat ion of th e column s with m inimu mnoise. Although t his t echn ique ha s not been u sed for seism ic applications, such a s


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stone column s an d san d piles, it ha s potent ial for liquefaction m itigation. Weat her isnot a problem.

AuGeo pi l ing, a Du tch technology and a register ed tr adem ar k of GeotechnicsHollan d BV, was a lso int roduced in Sweden as a ra pid, economical met hod forconst ru cting column -support ed emba nk men ts in ver y soft soils. This met hod consist sof using a ma ndr el to push , vibrat e, or dr ive a lar ge-diam eter plast ic pipe thr ough softsoil, then filling t he pipe with concret e to form a column . QC uses convent iona lconcrete sam pling an d test ing. Load test ing is perform ed to confirm perform an ce. Fordesign, the scan team believes that field measurements of spacing, diameter, anddepth could ea sily be evaluat ed. The scan t eam also believes th at only avera ge pileequipment skills would be required. Contracts could be prepared on performance-based specificat ion with concret e sam ples an d test ing perform ed by the owner forconfirma tion. Additional informa tion will be solicited on th is t echn ology as par t of th escan implement at ion program.

Th e rock saw , a cable type saw, is an alter na tive to blast ing for ma king rock cuts a ndshafts in r ock. The technique does not appear to be any faster t han blasting, as the

rock sa w r equires predr illed h oles for setu p. However, the technology may s till speedup const ru ction by allowing for n ight const ru ction in ur ban ar eas given its low noisean d lack of vibra tion. The t echnique a lso resu lts in a u niform , smooth cut, whichreduces the noisy jackhammer dental work. The technique does require specializedequipment. However, we underst an d th at neither the equipment nor th e process ispaten ted. The equipment is a lso readily available in th e United St ates becau se it iscomm only used in qua rr ying opera tions. A video demonst ra ting t his t echnology wasprovided, as is listed in th e bibliogra phy section of this r eport (see Appendix C).

Rapid impact compact ion, as indicated in t he pr evious section, is a t echn iqueusing a 5-ton, 1-met er dr op hydrau lic pile ha mm er t o compa ct the soil, an d was

presented as an accelerated construction method by the United Kingdomsrepresent ative from BRE. This t echnique basically uses a hydrau lic piling ha mm er t odrive a lar ge foot into th e ground. This technology elimina tes excavat ion a nd a llowsfor compa ction of sha llow layers up to 9 ft (3 m) th ick. The technique was in itiallydeveloped by the military for repair of bomb damage to airfields. (Reportedly, the U.S.Army Corps of Engineers also perform ed some init ial work on t his t echnology forrapid airfield repair.) The British are currently evaluating this technique forcompa ction of loose fills su ch a s const ru ction ru bble, sha llow r efuse, indus tr ial wast efills, or loosely placed dumped fill. The team also discussed use of the technique forincreasing conventional lift thickness during embankment construction.

The technique ma y also ha ve some a pplicat ion in d ensifying sh allow, liquefiablelayers t o limited dept hs in seismic zones. Cost in form at ion wa s n ot available. Thetechnique r equires specialized equipment, but ther e does not appear to be a pat ent onthe process or the equipment. The equipment is readily available in th e Un itedSta tes, and n o special tr ainin g should be required t o apply this technology. The scanteam also believes that standard density testing could be used for quality control.Cont ra cting could be per form ed on a per form an ce-based specificat ion with resu ltsmea sur ed by CPT tests before a nd a fter placement . The cont ra ctor is responsible for


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perform an ce of meth od on th e basis of test ing resu lts. Some noise and vibra tionissues m ay ha ve to be addr essed, similar t o pile driving.

Vibro-jet sheet pile driving , currently being evaluated by the United Kingdom,combines vibra tory pile driving with jetting pr ocedures t o significan tly speed u p sh eetpile insta llation. This t echn ique a llows t he effective inst allat ion of sheet pilingthrough clays that are far too stiff for conventional impact or vibratory hammermethods. The team also noted that the jet conduits could be used after driving togrout the sheets in place and, thereby, eliminate any reduction in lateral fixity causedby the jetting pr ocess.

J ett ing ma y redu ce dura tion of vibra tory driving. However, if spoil is und esirable,jet t in g may not be a via ble opt ion . The t ech nique requir es specia lized equipmen t , bu tpatents do not exist on the equipment or the process. The equipment is readilyavailable in th e Unit ed Sta tes. Design techniques for convent iona l sheet piles wouldapply; however, the use for axial loading capacity is unknown. QC would be based onfield observat ions of the per form an ce. Tra ining would be r equired t o opera te avibra tory ha mm er. Calibra tion would be requ ired t o suit site condit ions. As with

convent iona l sheet pile insta llation, contra cting could be performed on a perform an ce-based specification. Usua lly sheet piling is t empora ry, so the cont ra ctor is solelyresponsible for perform an ce.

A unique r esear ch opportu nity exists for vibro-jet sheet piles. The Br itishorganizat ion per form ing resear ch on t his technology, BRE, has cur ren tly exhau stedits funds for furth er resear ch a nd ha s ra w data from vibro-jet r esearch tha t h as yet tobe put into fina l form . Included in t his r eport is inform at ion from r ecent projects. BREwould be very inter ested in sha ring th is inform at ion, if the Un ited Stat es wanted t ocont inue th e evalu at ion of th is t echn ology.

Screw pi l es ar e also being used in t he Un ited Kingdom, with installation requiringone-third the time required for auger-cast piles. Advanced information was presentedto a few of th e scan tea m m ember s in En gland pr ior t o th e tour. Two types of systemswere discussed dur ing th e Swedish session, including: (1) D2A in wh ich th e hole sizeis ma tched to th e soil type, an d (2) Screwso l in which th e concrete r equired t o formth e pile is minim ized. Discussions included load test ing an d special tr ainin grequirements for both techniques. Performance-based contracting is being used by theBritish for both pile types with the owner making measurements on the in-place piles.Significan t inform at ion on th is techn ology was pr esent ed dur ing the Belgium t our, asis reviewed later in this report. Load testing special training is required.

The British ar e also evalua ting the reuse o f foundat ions as a meth od to accelera te

const ru ction. This techn ology elimina tes time to repla ce foun dat ions. Evalu at ionconsists of load testing, field verification of existing foundations and their dimensions,an d nondest ru ctive test s for int egrity an d dur ability. This technology has a lso beenused in t he Un ited Stat es, an d, like the Br itish, we have found tha t a very specialeffort is required by th e geotechnical engineer. Cont ra cts ar e usu ally based on a timeand materials basis.

The u se ofsteel pipe pi l ing, identified by Finla nd a s its m ost comm on pile type, isbased on t he speed of driving th rough boulders. This piling met hod is common


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pra ctice in t he Un ited Sta tes a nd is not necessar ily a new accelera ted constr uctionmet hod; however, becau se of its exten sive use, Finlan d h as also developed aninnovative direct conn ection from th e steel pipe piles to the su perst ru ctur e. Theeliminat ion of a p ile cap, pier column , and pier cap saves significan t t ime du ringconst ru ction. The insta llation of the piles is convent iona l technology tha t is cont ra ctedon a perform an ce basis based on blow counts. The connection is a st an dar d deta il

requiring no special training. Noise and vibration potentially limit urban production,but th e piles can be prebored to limit t his problem.

Another a dvancement in Finland is the development of an automated rapid s i teinves t igat ion technique using resistivity. This is an extension of Finlan ds work inevalua tion of pavemen t syst ems, which combines r esistivity a nd falling weightdeflectometer (FWD) measu remen ts. The F innish a re curr ently evaluating th e use ofresistivity profiles to rapidly estimate water content and consolidation settlement.This technology has significant potentia l to save time in prelimina ry geotechnicalinvestigations an d layout of final borings. A similar initiat ive is un der way by th eFH WA in t he Un ited St at es, and a coopera tive effort could pr ovide for a m ore r apiddevelopment.

LESSONS LEARNED: PREFABRICATED TECHNOLOGIES

SCC , as discussed in th e previous section, was also identified by the t eam as aprefabr icat ed t echn ology with significan t U.S. applicat ion potentia l. SCC r equires novibra tion an d th us pr oduces no noise and speeds u p const ru ction. The t echnology hasbeen u sed successfully in Sweden over th e past 4 years on m ore th an 20 projects. Forexamp le, SCC was us ed in th e concret e rock lining of th e Sdra Ln ken Tun nelPr oject, which th e tea m visited. Based on t he Swedish project experien ce, a 10 to 15percent t ime an d cost sa vings has been ident ified in addition to the positive impact onth e work environmen t (i.e., low n oise a nd vibra tion). Becau se of the low n oise, th is

technology would a lso benefit night time const ru ction. Specialized equipmen t is notneeded, but n ew processes an d skills are n eeded to ha ndle th e more fluid mix (e.g.,work ability test , pour ra te, form pressu re, an d form design). Sweden does not ha vedesign requirement s for ea rth quake, and thu s ha s no experience in applicat ion inseismic regions. Special consider at ion for cold weat her concrete placement ma y alsobe needed.

The direct conn ection of pipe piles to th e bridge str uctur e used by F inlan d, which wasdiscussed in t he previous section, is a nother prefabr icat ed t echn ology.

LESSON S LEARN ED: STATUS O F LIM IT STATE DESIGN

In relation to limit state design, the United Kingdom provided us with a special issueofCivil En gineering magazine on Eurocodes (November 2001, Volume 144, SpecialIssu e Two), which conta ins a n excellent overview of the developmen t an d curr entsta tu s of th e E ur ocodes, including E ur ocode 7: Geotechnical Design. The inform at ionon Eu rocode 7 is r eproduced in Appendix E with perm ission of Civil Engineer ing,Thomas Telford publishers, as a follow-up to the previous 1999 geotechnicalengineering pr actices tour.


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CHAPTERTHREEGERMANY

The second visit of the st udy t our wa s t o Cologne, Germ an y, on J un e 20 an d 21, 2002,for meetings at the German Federal Research Highway Institute (BASt), which issimilar to th e F HWA Tur ner-Fairba nk resea rch facility. The r eview involved form almeetings with a nd present ations by representa tives of var ious depar tm ents within

the BASt a s well as a represent at ive from the Bundesministerium for Verkehr, Bau-un d Wohnun gswesen (Germa ny Ministr y of Tra ffic, Const ru ction a nd Housing).Presentations were also made by representatives of the private sector, including:

Mbius Bau-Gesellschaft GmbH & Co., a contr actor with specialization in theinsta llation of geosynt het ic-encased column s.

Huesker Synthetic GmbH & Co. KG, a geosynthetics man ufacturer and developerof the geotextile for geosynthetic-encased columns.

Bauer Spezialt iefbau GmbH, a design-build contra ctor and equipmentma nu factu rer with specializat ion in s oil stabilizat ion with vertical column s (CSV)

an d deep soil mixing.

Friedr. Ischebeck GmbH, a specialty contr actor a nd developer of self-drilling andgrouting na ils and m icropiles.

BOMAG GmbH & Co. OHG, a m anufacturer of compaction equipment.

On th e second day in Germa ny, the t eam m et with th e highway depart ment inMeschede and attended a presentation on its activities, including a roadwayconst ru ction project wher e extens ive rock slide an d cut slope st abilizat ion p roblemsha ve occur red. We m ade a field visit to th e r oadway const ru ction project site (figure8). The t eam th en m ade a s econd site visit to a geosynthet ic-reinforced, mechan ically

sta bilized eart h r eta ining wall project, which wa s const ru cted with a green steelmesh facing u sing r ecycled, cont am inat ed const ru ction debris a s fill (figure 9). Theuse of contaminated fill for embankment construction was also encountered in severallocations in Belgium (airport and rapid rail).

The current construction of rapid rail lines in the Netherlands, Belgium, Germany,an d Ita ly ha s been a sh owcase for inn ovation. On the wa y to Germ an y, the tea m t ookth e opport un ity to visit t he Giessen-Oudeker project (a high-speed freight ra il project)in t he vicinity of Rott erda m, th e Net her land s. At th is specific port ion of th e pr oject,the Betuwe route, they were constr ucting a cut a nd cover tun nel for t he twin r ail linebelow an existing river in a resident ial ar ea (figure 10). Self-boring m icropiles a re

being used to act as both a tiedown for hydrostatic pressure and vertical support asthe tr ains pass through th e tunnel.


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CHAPTER THREE: GERMANY

Figu re 8. Field visit to M esch ed e

roadw ay s lope stab i li za t ionproject.

Figure 9. Green- faced w al l si te visit .

Figu re 10. Site visit to the Betuw e ra ilwa y l ine (in the N ethe rland s).


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IDENTIFIED ACCELERATED CONSTRUCTION TECHNOLOGIES

In Ger ma ny, a pr ocess was pr esent ed to evaluat e which m eth od would provideoptimum acceleration considering the total scope and integration with all phases ofth e pr oject (i.e., how accelerat ed const ru ction met hods fit in with t he critical pat h forproject completion). A project stu dy on accelerat ed const ru ction with regar d t o theAutobahn A-26 was presented to demonstr at e th e technique.

The German group presented their experience with a variety of foundationtechnologies, including geotextile-encased columns, which accelerate dewatering plusimpr ove support ; emba nk men ts on piles, which elimina tes pr eloading; geosynth eticreinforcemen t su pport of emba nk men ts on piles or column s; a combined s oilsta bilization system (CSV), which provides a one-step in sta llation of cement column s;an d th e drilled-in, self-grouting micropiles used on the pr oject in t he Net her lands.Another presentation discussed the use of instrumentation on the compactionequipment to measure dynamic modulus for improvement compaction uniformity andevalua ted r equired effort a nd u se of this equipmen t for compa ction cont rol.Discussions were a lso held on keeping the designer on boar d dur ing constr uction t o

ra pidly resolve issues or modify design a nd br ing the cont ra ctor in du ring design toidentify meth ods to accelerat e const ru ction.

As in Sweden, the significant factor in Germany is maintaining traffic duringconst ru ction, which often drives th e const ru ction pr ocedures a nd h as led toinnovations in parallel bridge construction. The German group presented informationon their cur ren t u se of prefabr icat ed steel bridges to save time a nd cost overtr aditional pr ecast concrete bridges. They also reviewed severa l bridge reconst ru ctionprojects in wh ich t he n ew bridges were const ru cted adjacent t o existing bridges, an dth en m oved into place on t he existing alignmen t a fter th e old bridge was dem olished.Tota l project disru ption t o tra ffic: appr oximat ely 72 hours.

LESSON S LEARNED: ACCELERATED CON STRU CTION M ETHODS

The following section reviews th e a ccelerat ed const ru ction met hods ident ified inGermany in relation to the amplifying questions.

In Germ any, a more in-depth pr esentat ion was ma de on t he use ofgeotext i l e -encased co lumns (or geotext i l e -coated co lumns), a technology identified duringth e Swedish tour. As n oted in t he s ection on Sweden, th is technology consists ofinsert ing continu ous, seam less, high-str ength geotextile tu bes into soft soil with ama ndr el and filling the tu be with sa nd (or fine gravel) to form a colum n with a h ighbear ing capa city. Displacemen t m eth ods can be u sed for in sta llation of th e column s in

very soft soils, and excavation (e.g., augering) methods can be used in stiffer soils.Constr uction loads ar e tra nsferred thr ough th e columns onto the un derlying natu ra lfoun dat ion. In a ddition, th e soil sur roun ding the column s is impr oved th roughconsolidation, which further improves the embankment support conditions anddecreases seconda ry sett lement s. A horizont al layer of high-stren gth geotextile isplaced over th e colum n h eads t o tr an sfer load bet ween column s. Const ru ction t ime issaved thr ough direct emban kment support , decreasing or eliminat ing stagedconst ru ction an d su rchar ge loadin g. Time for seconda ry set tlemen ts of the soft soil isalso decreased. Several case histories were presented, which demonstrated both the


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const ru ction t echn iques an d th e poten tial for u se of this ra pid met hod for st abilizingvery soft gr oun d or organ ic soil. Document at ion of these a pplicat ions wa s m adeavailable (in German) with field measurements. This information requires criticalevalua tion for in str um ent at ion, especially in rela tion to design. No design code iscur rent ly available. The m ethod is cur rent ly designed a nd installed with theassistan ce of the proprieta ry cont ra ctor an

Documents

Innovated Technology for Accelerated Construction of Bridge and Embankment Foundations in Europe