1. SHRP 2 - First Demo Project Keg Creek, Iowa R04 – “Bridge Designs for Rapid Renewal”
Sandra Larson, P.E.
Iowa Department of Transportation
Research and Technology Bureau Director
RAC/TRB 2012 Annual Meeting
Burlington, VT

2. THREE MESSAGES 2
SHRP 2 Overall Plan - Leading to Implementation of Products
Accelerated Bridge Construction (ABC) Background
Iowa’s SHRP 2 Demo Project Details– Keg Creek
Thanks to Neil Pedersen (SHRP 2) and Ahmad Abu-Hawash (Iowa DOT) for slide information

3. SHRP 2 (Second Strategic Highway Research Program) Overall Plan - Leading to Implementation of Products

4. SHRP 2 PLAN Research (2005 - 2013) Development (Now through 2015)4
Research ( )
100+ research projects
Administered by TRB
Development (Now through 2015)
Pilots and demonstrations
Testing and refinement of products emerging from research
Implementation ( forward)
Partner agencies prioritize products for implementation
Selected products systematically integrated into current transportation practices

5. Keg Creek - SHRP 2 Demo Project5
SHRP2 funds:
$250,000 for construction
Assistance with design of bridge through consultant
Assistance with project details and problem solving
Held showcase, produced video
HFL funds: $600,000 or 20% of construction cost
Iowa DOT research and construction funds, staff time, commitment of resources
Iowa State University research testing

6. SHRP 2 Focus Areas
Safety: fostering safer driving through analysis of driver, roadway and vehicle factors in crashes, near crashes, and ordinary driving
Renewal: maintaining and repairing the deteriorating infrastructure using already-available resources
Reliability: managing non-recurring events to create more predictable travel times
Capacity: building a highway system that creates minimum disruption and meets the environmental, and economic needs of the community.

7. SHRP 2 - Definition of Success
5-6 States adopt as standard practice
Additional states follow the lead
AASHTO and FHWA provide continuing support
Private sector buy-in
Positive impact on practice
Cost-effective use of products

8. Accelerated Bridge Construction (ABC) in Iowa

9. Iowa DOT ABC Deployment Strategy – past several years9
Develop skills and design details through demonstration projects (IBRD, HfL, SHRP2, ..)
Invest in research and include laboratory and field testing to confirm constructability and performance.
Participate in national pooled fund studies
Involve local construction industry and hold ABC workshops.
Develop policies for ABC

10. ABC/PBES
Prefabricated Bridge Elements and Systems (PBES): it is a strategy to accelerate bridge construction that employs prefabricated individual Elements such as beam, deck, abutment footing, pier column, pier cap, etc. Or entire superstructure System that is assembled off-site and moved into place.
What is PBES?

11. Why use ABC? To deal with schedule constraints
Limited time-window due to special events
Emergency replacement due to natural disasters, accidents, or intentional acts
To minimize impact on local traffic
Access to business
Commuters
Essential services
To deal with the unavailability of suitable detour
To deal with schedule constraints such as limited time window due to special events or emergency replacement due to natural disasters, accidents, or intentional acts.
To minimize impact on local traffic by providing access to businesses, commuters, and essential services such as hospitals and fire protection
To deal with the unavailability of suitable detours.

12. ABC: Benefits Reduced public inconvenience Improved public perception
Improved road users and workers safety
Reduce negative economic impact on local businesses
Perhaps improve the durability of the structure
The primary benefits of ABC:
Reduced public inconvenience: by not having to go through construction zone or take a detour for full construction season (typically six months or more)
Improved public perception: an example is driving in construction zone on Saturday with traffic restriction and no work being done
Improved road users/workers safety: shorter exposure to construction hazard for both the public and workers
Reduce negative economic impact on local businesses: people try to avoid construction zone therefore local businesses suffer
Perhaps improve the durability of the structure: in the case of precast components fabricated in controlled environment quality is improved

13. ABC: Disadvantages
Substantial increase in construction cost: fewer bridge replacements
Contractors are generally uncomfortable with the PBES concept: higher cost
Requires the development of new design standards and specifications: higher design cost
If you are only considering direct cost, there are definite disadvantages associated with ABC

14. Case Study: Keg Creek Lessons Learned SHRP 2 Program First Demo Project

15. Keg Creek Bridge - IT’S A BIG DEAL -15
Iowa DOT wins America’s Transportation Award, announced July :
The Iowa DOT received an award in the “Best Use of Innovation” category for the U.S. 6 bridge over Keg Creek in Pottawattamie County.
This bridge was completely prefabricated off-site and then assembled at the construction site using an accelerated bridge construction method. Utilizing this approach, the road was closed for only two weeks.

16. Background
SHRP2 – R04 Research Team needed to demonstrate ABC design concept for typical multi-span stream crossings – a common rural bridge replacement
Proposed a demonstration project in Iowa
Successful project may pave the way for developing national ABC standards
A bridge on US 6 over Keg Creek in Pottawattamie County met the objectives

17. 180’ x 28’-0 Continuous concrete girder bridge
EXISTING BRIDGE
180’ x 28’-0 Continuous concrete girder bridge
Built in 1953
3 spans 53’6”,73’,53’6”
Moderate sized, typical rural crossing
Small, meandering stream
Narrow bridge width on primary road system
Sufficiency rating 33
The existing structure is 180 by 28 continuous concrete girder bridge
Built in 1953
3 span
Typical rural crossing over small meandering stream
It is FO because of the narrow width with sufficiency rating of 33

18. Keg Creek - Project Data
Design: HNTB
Testing: ISU
Bridge Construction Cost: $2,658,823
Unit cost: $231 per sq.ft. ($124 estimated for conventional in Iowa)
Incentive/Disincentive : $22,000 per day
SHRP2 funds: $250,000
HFL funds: $600,000 or 20% of cost
New bridge: 204’-6 x 44’-0 Prefabricated Steel Modular Superstructure on Precast Substructure supported on Drilled Shafts.

19. Why Keg Creek?
Typical rural, moderate size stream crossing in Iowa. Indicative of many bridges throughout the mid-west and country. SHRP2 looking to standardize ABC design plans.
Detour: 22 mile detour less desirable for traveling public over 4 to 6 month period versus 2 week ABC period.
Schedule: already programmed for 2011 construction.

20. Iowa Bridge Farm (Phase 1)

21. Precast Substructure Components Casting (Phase 1)

22. Superstructure Modules –Structural Steel Assembly (Phase 1)

23. Superstructure Modules – Deck Forming (Phase 1)

24. Deck Concrete Placement (Phase 1)

25. Drilled Shaft Construction (Phase 1)

26. Abutment / Wing Erection
26 kips
Abutment / Wing Erection
93 kips

27. Column Assembly
52 kips

28. Bedding and Coupler Grouting

29. Cap Beam Assembly
168 kips

30. Superstructure Module Transport
kips
69-80 kips

31. Module Assembly

32. Module Assembly

33. Final Module Placement

34. Flooded Backfill System

35. Precast Approach Preparation
35 kips

36. Precast Approach Slab Placement
31-37 kips

37. UHPC Placement

38. Completed Bridge

39. Conclusions
R04 - ABC design concept was successfully demonstrated, but there were some challenges along the way.
Post construction review identified problem areas, as expected, and provided recommendations for improvements which will be documented in the final report.
As the result of this project (and other past ABC projects), Iowa DOT gained a better understanding of risks and benefits associated with ABC and is developing ABC policy and planning more ABC bridges.

40. Ahmad Abu-Hawash, Iowa DOT
Project Website
Questions?
Thanks to:
Neil Pedersen, SHRP 2
Ahmad Abu-Hawash, Iowa DOT
For slide material