1. Spliced Girders A Producer’s Perspectiveby
Chad Saunders
Chief Engineer
Bayshore Concrete Products
presented at the
Virginia Concrete Conference
Richmond, Virginia
March 11, 2005

2. Bayshore Concrete Products Cape Charles, VA
90 acre casting facility on Cape Charles Harbor and Chesapeake Bay

3. The shape. How did we get here?
PCEF
Prestressed Concrete Committee
for Economic Fabrication
A committee established by FHWA for economic fabrication of prestressed/precast concrete
Consists of Mid Atlantic states

4. PCEF Cross Section Variability
6” ” ”
Different web thicknesses = diff. soffit

5. PCEF Cross Section Variability
58” ” ”
12” wider top flange = same side form
with blockout removed

6. Form modification

7. VDOT PCBT 32” bottom flange width 7” thick bottom flange 7” web
47” top flange width
DESIGNATION
DEPTH
AREA
CENTROID TO BOTTOM
MOMENT OF INERTIA
WEIGHT (150 PCF)
(IN)
(IN2)
X (IN4)
LBS/LF
PCBT-29 29
634.7
14.66
66.8
661
PCBT-37 37
690.7
18.43
126.0
720
PCBT-45 45
746.7
22.23
207.3
778
PCBT-53 53
802.7
26.06
312.4
836
PCBT-61 61
858.7
29.92
443.1
899
PCBT-69 69
914.7
33.79
601.3
953
PCBT-77 77
970.7
37.67
788.7
1011
PCBT-85 85
1026.7
41.57
1007.2
1070
PCBT-93 93
1082.7
45.48
1258.5
1128

8. Rte 123 over the Occoquan River Fairfax and Prince William Counties
VDOT’s first PCBT spliced girder bridge

9. Close proximity to I-95 and Route 1 = detour = high traffic
Location
Close proximity to I-95 and Route 1 = detour = high traffic

10. Affluent neighborhood = pressure for aesthetic design
Town of Occoquan
Affluent neighborhood = pressure for aesthetic design

11. Who’s Who Owner – VDOT Designer – Moffatt & Nichol
General Contractor – Archer Western
Erection Engineer – McNary Bergeron
Precast – Bayshore Concrete Products
PT Hardware - VSL

12. Approach Girders (4 spans)
Erection plan
Approach Girders (4 spans)
End Span Haunch Drop In Haunch End Span

13. Bridge Cross Section
At Haunch Piers
Other piers

14. Concrete Concrete – 28 day: 8000 psi Concrete - release: 5800 psi
Low permeability
Release strength cylinders matched cured

15. Approach Girders 4 span unit Pieces: 58 total beams Type: PCBT-77
Length: 144 ft
Weight: 73 tons
Strand: 0.6” LRS
Cast two per pour
Cross section

16. Approach Girder Casting setup
Gravity abutment to withstand prestress force
Conventionally prestressed
with draped strands

17. Maturity meter testing
Research for more accurate prediction and control of camber by VA Tech

18. Forms and casting Side forms with fall protection rail
Placing concrete with Tuckerbuilt

19. Storage
300 ton twin gantry crane in background

20. Spliced Girders End span Haunch Drop-In Pieces: 28 total beams
Length: 127 ft
Weight: 88 tons
Haunch
Length: 98.5 ft
Weight: 77 tons
Drop-In
Pieces: 14 total beams
Length: 137 ft
Weight: 87 tons

21. Special form needs End span and Drop-In Haunch Approach 34” soffit
(4) sections of end block form (end span only)
Extra 2” angle full length of side forms to create 6” thick top flange
Haunch
Complete form system including soffit and side forms
Approach
Standard PCBT-77

22. Erection Sequence Temporary support
Erect haunch segment then end span segment
Back span = 185 ft
Erect drop-in segment
Main span = 225 ft

23. Erection Sequence Make closures and begin PT Remove strong backs
Cast deck and complete PT

24. End Span and Drop In cross sections
Type: Modified PCBT-77
Depth: 79”
Strand: 0.6” LRS
Variations:
6” thick top flange
9” wide web for PT tendons = 34” wide bottom flange & 49” wide top flange
Cast two per pour
End Span and Drop-In End Block at End Span

25. End Span end condition PT ducts: (3) 4” OD for 0.6” LRS
Extremely congested area due to bursting reinforcement

26. End Span and Drop-In connection at splice with haunch
Very congested area due to splice plates with welded rebar and projecting rebar

27. Casting setup
Ducts in place
Setting ducts

28. End block
Up close near anchorage
Horizontal reinforcement

29. End block
Termination of end block
Pre-assembly of end cages

30. Splice End
Top splice plates
Bottom plates and projecting bars

33. Haunch Type: Modified PCBT-77 Depth: varies from 79” to 12’-6”
Strand: 0.6” LRS
Variations:
6” thick top flange
9” wide web for PT tendons = 34” wide bottom flange & 49” wide top flange
Cast one per pour

34. Haunch
NTS
nts
Challenges:
12’-6” depth at midpoint = extreme height full length
Most strands located in top flange
Location of the PT tendons makes concrete placement and consolidation difficult = addition of pour windows
Extra setup required for storing and handling of variable depth side forms and beams

35. Bed setup

36. Pulling strand

38. Stressing

39. Rebar and PT tendons

40. How did he tie the bars in the top flange?

41. Forms

42. Grout vents
Top Splice Plate

43. Look at the view from up here.
Pouring with buckets

44. First casting is a success
Girder bracing

45. Shipping
All beams to be shipped by barge starting early April 2005

46. Erection
Phase I – setting beams from the existing bridge

47. Erection
Phase II – setting beams from the phase I bridge

48. Lessons learned
Producer - Seek possible use of SCC concrete for heavily congested area
Contractor - Get “construction engineer” involved early to ensure means and methods are established (i.e. temporary bracing embedments, special lifting requirements, strong back design, etc.)
Engineer - Require complete shop drawings from PT supplier
DOT – consider having a notch in back span girder(s) designed and included in plans to ensure maximum flexibility in construction sequence

49. Rte 33 over the Pamunkey River West Point and New Kent County
What’s Next?

50. Location

51. Town of West Point

52. Who’s Who Owner – VDOT Designer – Parsons Brinckerhoff
General Contractor – Tidewater Skanska
Precast – Bayshore Concrete Products

53. Concrete Concrete – 28 day: 8000 psi Concrete - release: 6000 psi
Low permeability
Lightweight: 115 pcf (concrete)
125 pcf (total)

54. Approach Girders 3 span unit Pieces: 21 total beams
Type: Modified PCBT-93
Variations:
9” thick bottom flange
8” wide web = 33” wide bottom flange & 60” wide top flange
Depth = 95.5”
Length: 137 ft
Strand: 0.5” LRS
Cast two per pour
Cross section

55. Spliced Girders End span Haunch Drop-In Pieces: 42 total beams
Length: 159 ft
Haunch
Pieces: 28 total beams
Length: 80 ft
Drop-In

56. Haunch Type: Modified PCBT-93 Depth: varies from 95.5” to 10’-5 1/2”
Strand: 0.6” LRS
Variations:
8” wide web for PT tendons = 33” wide bottom flange & 60” wide top flange
Cast one per pour

57. Haunch Challenges: Pros:
10’-5 ½” depth at midpoint = setup remains at 12’-6” to avoid costly rework = extreme height full length
Others same as previous project.
Pros:
Not having to set up a new stressing frame
Booster Form – utilize existing forms
Haunch

58. Special form needs End span and Drop-In Haunch Approach 33” soffit
(2) sections of end block form (end span only) – different from Occoquan because same quantity of end span and drop-in
16” riser for PCBT-77 form
Haunch
Booster form (bolts on to bottom of standard form)
Approach
16” riser for PCBT-77 form (same as above)

59. Questions?

60. Thank You
Please feel free to come visit our plant OR call if we can be of assistance in any way
Contact: Joe Rose

61. Bayshore Concrete Products Cape Charles, VA
90 acre casting facility on Cape Charles Harbor and Chesapeake Bay