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Innovative Bridge Designs for Rapid Renewal. HNTB Corporation Iowa State University, Ames, IA Structural Engineering Associates, San Antonio, TX Nyleve Bridge, Emmaus, PA Walsh Construction, Chicago, IL. Transportation Research Board SHRP2 - Project R04. How do we construct bridges quicker?
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Innovative Bridge Designs for Rapid Renewal HNTB Corporation Iowa State University, Ames, IA Structural Engineering Associates, San Antonio, TX Nyleve Bridge, Emmaus, PA Walsh Construction, Chicago, IL Transportation Research Board SHRP2 - Project R04
How do we construct bridges quicker? • How do we make them durable for 75 – 100 years? • What technical issues are in the way? • What deployment issues are in the way? Major Questions
R04 Findings – Major Themes • Strong impetus to use ABC • Support (real or perceived) is strong at most levels • Reluctant agencies list cost as the main impediment • ABC, when used, has a remarkable satisfaction rate • DB, A+B and ID contracts most common Owner Initiatives
Project Survey – Main Themes • Common reasons traffic and worker/public safety • Few agencies have an ABC process • Reasons for not employing ABC • Requires more research • Requires institutional change • 5 agencies provided specifics on ABC projects • User costs only considered to be real costs by 1 in 5 DOT’s • Benefits considered to outweigh costs by all 5 DOT’s Owner Initiatives
Many “Flavors” of ABC • Florida • Several SPMT projects completed; more planned • Some use of precast pier construction • Texas • Significant use of prefabricated substructures • Use of U-beams for rapid superstructure erection • Utah • Developing a standard agency policy centered around rapid replacement • North Carolina • Creation of Alternative Delivery Unit Owner Initiatives
UDOT CMGC • Owner hires the engineer and contractor, simultaneously, via separate contracts • NC DOT Washington Bypass • Design Build Best Value • Ministry of Transportation Model (Clyde Avenue) • Only selected pre-qualified general contractors invited to be bid • GC’s required to submit credentials of one or more heavy lifters for additional prequalification. Innovative Contracting
European Model (reference – Freyssinet / Hebetec) • Owner mandates specialty methods of erection • Owner hires the specialty contractor or lifter • Engineers required to design a compatible solution • GC is required to construct the chosen solution • Much less “fear” about engineer / contractor interaction during design phases • User costs are highly valued Innovative Contracting
Contractor Concerns • If ABC shifts to large scale prefabrication and use of specialty movers, what is the role of the GC? • Has implications on profit and responsibility • Current contracts involve expensive subs • Lack of control of a large portion of the bid price • Engineers should not dictate methods of construction Innovative Contracting
Washington Bypass Pictures from Flatiron Construction
115 ft span capability; depth / span 36 • With 4” c.i.p. topping and exterior barriers, segment weight is 150 tons • Contractor places 2 spans per night TxDOTPre-Topped U Beams
Structure built on raft foundation • 35m bridge; 2400ton; movement time < 5 hours • Suitable for poor subgrade conditions • Pressure < 10 psi FreyssinetAutoripageSystem
Standard section designed by VSL • Works in span by span, balanced cantilever and full span launching • Segment size 15m x 3m x 90 metric tons • Segments can be made in advance and stockpiled Westlink M7 Motorway
Relative to superstructures, much less work in this area • FHWA 2002 Scan Tour identified some promising technologies • Self-Drilling Piling (grouted or screw piles) • Continuous Flight Auger piles w/ automated control • Cased secant piles • Hydro-Mill continuous walls ABC Bridge Foundations
Continue data gathering and reviews • Determine what methods have promise • New bridge design concepts that better use innovative construction techniques • New / refined construction techniques for existing / new bridge concepts • Implement new research • Coordinate with other SHRP2 projects • R02 Foundations • R07 Performance Specifications • R19 100 yr service life Where to From Here?
Thank You Dr. Francesco M. Russo, P.E. FRUSSO@HNTB.COM