1. Presented By: Marvin Burns, PE Janssen & Spaans Engineering, Inc.
Practices needed during design, shop drawing preparation and construction of long span post-tensioned bridges 2 Construction Techniques
Spliced, Post-tensioned, Precast Girders
Cast-In-Place Balanced Cantilever
I-355 Bridge over Des Planes River Valley
270’ main span - Illinois Tollway Authority
Design Build
SMART Bridge
472’ main span - Virginia DOT
Construction Engineering
Presented By:
Marvin Burns, PE
Janssen & Spaans Engineering, Inc.

2. Responsibilities Design Engineer Adequacy of design
Provide details that are workable with only minor conflicts that can be resolved in the shop drawings
Erection Scheme that meets industry practices
Construction Engineer
Preparation of Shop Drawings for each segment that combines various elements shown on contract plans with erection hardware and post-tensioning hardware. These items often have proprietary details and cannot be finalized until the Supplier has been selected.
Shop Drawings showing placement of rebar with minor repairs from that shown on contract plans to avoid post-tensioning anchorages and ducts.

3. Responsibilities
Construction Engineer for Cast-In-Place Balanced Cantilevers
Provide detailed erection analysis based on Contractors Erection Sequence and Calendar. Analysis includes stress/capacity design checks for each step of erection; including time effects for creep and unbalance moments during weekly cycles.
Services include camber diagrams made from the deflections and procedures to control geometry for erection segments.
Calculations for tendon forces and elongations using friction coefficients associated with the tendon duct supplied by the post-tensioning supplier.

4. Contractor / Construction Engineer
The Construction Engineer’s duties and responsibilities are described in, and governed by, a written contract with the Contractor. Duties will generally include requirements imposed by the Owner in the special provisions.
Contract documents usually contain minor conflicts. Although many of these are caught and cleaned up during preparation of the shop drawings there is an expense in money and time associated with how much detail is needed by the Contractor to be able to build from the shop drawings.
The Contractor has tight schedules and cannot wait for shop drawings to be perfect before work proceeds. At a certain point the Contractor has to cut off the planning stage and get on with the work.

5. Spliced, Post-tensioned, precast concrete girder
US 27 over Caloosahatchee Canal
Moore Haven, FL
3 Spans (210’-320’-210’)
320’ National Record held by JSE Completed Winter 2001
KY 22 over Kentucky River
Gratz, Ky
4 Spans (175’-200’-325’-200’)
325’ National Record held by JSE Completed Summer 2010
Featured in Aspire magazine in Winter 2011

6. I-355 Bridge over Des Plaines River Valley Illinois Tollway Authority Performance Based Alternate
35 Spans divided into 8 Units - 2 structures at 6,600 ft each
102” Deep Post-Tensioned Bulb Tees, PT Beams Haunched to 120” on Main Spans
90” Prestressed Beams
Post-tensioned Spans Ranged from 216’ to 271’
Prestressed Spans Ranged from 114’ to 170’
Completed Winter 2007

7. Post-Tensioned Beams Spans Ranged from 216 ft to 270 ft
Beams Ranged from 113 ft to 150 ft

8. Post-Tensioned Beams Typical Beam Depth – 102 in
Beams haunched over Piers to 120 in
Brian

9. Post-Tensioned Beams
Falsework Required
Strongbacks
Brian

10. Post-Tensioned Beams
4 Tendons Per Beam Line
Brian

11. Post-tensioning

12. Post-tensioning

13. Tendon Grouting

14. Final Cost $125M Low bid - including engineering fees
$133M Second-place bid for Segmental Concrete Box Alternate
$147M Third-place bid for Steel Performance-Based Alternate
Bids include approach roadway and adjustment of features crossed
Brent

15. SMART Bridge – Virginia DOT Christiansburg, Virginia Construction Engineering
Contractor: PCL Civil Constructors
Construction Cost: 15 Million
Completion: 2000
5 Spans (284’-3 at 472’- 284’) = 1984’
Width = 36’-4”
Single Cell Box (2 Webs)

16. SMART BRIDGE
Concrete Pour using Tire Crane

17. SMART BRIDGE
Erection of Pier Table
Erection of Form Traveler

18. SMART BRIDGE

19. EB Wakota Bridge– Minnesota DOT Minneapolis, Minnesota Construction Engineering
Contractor: Lunda Construction
Construction Cost: $63 million x 2 bridges = $126 million
Completion: 2010
5 Spans (272’-328’-2 at 466’,358’) = 1890’
Width = 85’ typical and 105’ at end spans for acceleration lanes
DoubleCell Box (3 Webs)

20. EB Wakota Bridge
Front View
Side View
Erection of Pier Table

21. EB Wakota Bridge
Erection of Form Traveler

22. EB Wakota Bridge
Pouring of Segment using Pair of Pump Trucks

23. EB Wakota Bridge

24. Construction Loading PERMANENT EQUIPMENT Shear Transverse
Shear on Leading Edge
Actual Wt. vs. Plan
COG
1.4x Shear at Leading Edge

25. Construction Loading PERMANENT EQUIPMENT Shear Transverse
Shear on Leading Edge
Actual Wt. vs. Plan
CONSERVATIVE MAX
IDEALIZED
ORIGINAL DESIGN
CONST. DISTRIBUTION

26. EB Wakota Bridge
Inside View of Left Cell of Double Cell Box

27. General Structure Size Balanced Cantilever Construction

28. Rebar Congestion Double Cell Box
Wide double cell boxes can have larger tendon forces. It would make it easier to install confinement rebar for the anchorages if the concrete dimensions could be enlarged.
Single Cell Box

29. Rebar Congestion

30. Vertical Tendon Radial Force
Tendon Stressing Operation
Concrete Spall

31. Vertical Tendon Radial Force
Tendon Pop-Out
Vertical Radial Force

32. Vertical Tendon Radial Force
Tendon Radial Force is Unrestrained
Vertical Legs are
Too Far Apart
Tendon Radial Force is Restrained

33. Stirrups to Restrain Angle Change at Bulkheads

34. Tendon Radial Force Variable Height Box

35. Horizontal Tendon Radial Force

36. Horizontal Tendon Radial Force

37. Tendon Cross Over into Adjacent Duct

38. Horizontal Tendon Radial Force Concrete Removal

39. Tendon Duct is Crowding Anchorage Reinforcing

40. Tendon Duct is Crowding Anchorage Reinforcing

41. Questions Thank You