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The State of Practice for Highly Skewed Bridges Construction Perspective.

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Presentation on theme: "The State of Practice for Highly Skewed Bridges Construction Perspective."— Presentation transcript:

1 The State of Practice for Highly Skewed Bridges Construction Perspective

2 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective MAH

3 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective MAH : Spans: 5 (963) Girders: Skew = 0°

4 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective MAH : Frames: Slotted L4x4x½ –3 piece and 4 piece –Expected Deflection during Pour = Frame Spacing: 24

5 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Overhang from 4 to 4-3

6 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective MAH :

7 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Cross Frame

8 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Cross Frames

9 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective MAH : Structure was milled ¾ to 1 ¼ Structure was given a 2-3 microsilica overlay Extra tall overhang brackets were used to dissipate web loading on the adjacent sister structure. Remedy:

10 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective FAI

11 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective FAI : Spans: 3 (184) Beams: 45 Type III Prestressed Concrete Skew = 23°

12 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective FAI : Frames: Slotted MC 18x47.2 –Expected Deflection during Pour = 1 5 / 16 Frame Spacing: 38-10

13 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Overhang = 4-2 ½

14 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective

15 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective

16 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective

17 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective

18 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective FAI : The beam rotation also caused the deck to be thin and the resteel cover to be less than specified.

19 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective FAI : Fascia bearings at piers were replaced and beveled shim plates were added to address translational rotation. Corrections Performed:

20 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Topics: Typical Deck Forming Typical Overhang Forming Bridge Paving Machine Use of Screed Elevations

21 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Deck Forming: Generic Interior Cross Section

22 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Falsework Between the Beams Strut Hanger Deck Forming:

23 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Deck Forming: Hanger Soffit Haunch Edge Forms

24 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Corrugated, galvanized metal Assume 18 psf for additional concrete Stay-in-place forms (SIP):

25 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Stay-in-place forms (SIP):

26 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Stay-in-place forms (SIP): Clip angle

27 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Stay-in-place forms (SIP): Haunch Styrofoam

28 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Topics: Typical Deck Forming Typical Overhang Forming Bridge Paving Machine Use of Screed Elevations

29 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective

30 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Spacing is typically 2-3 Typically no haunch No SIP forms Vertical leg length is currently determined by capacity of bracket only.

31 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Inspection Rail

32 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Overhang brackets can cause localized buckling and rotation of deep girders

33 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Std. Max = 50 Deep Max = 70

34 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Topics: Typical Deck Forming Typical Overhang Forming Bridge Paving Machine Use of Screed Elevations

35 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective

36 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Rotating Rollers Augers Rail Vibrating Rollers

37 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well 3600 Max. Paving Width = 96 Basic Machine = 5990 lbs. Additional = 53 lbs. / ft.

38 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Wheel Base = 3 Bid-Well

39 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well 4800 Max. Paving Width = 120 Basic Machine = 7600 lbs. Additional = 75 lbs. / ft.

40 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Wheel Base = Bid-Well 4800

41 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well 4800 w/ 66 Deep Truss Max. Paving Width = 160 Specialty Item – Do Not Use without Consulting OCA

42 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Contractor Typical Method of Placement Deck Placement:

43 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Design Assumes Loading Along the Skew Deck Placement: - OR -

44 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Magical Simultaneous Loading Deck Placement:

45 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Load and finish along skew (±5°) up to 50°. Above 50°, finish at 50° and load at actual skew (±5°), but limit leading edge of concrete to 20 ahead of bridge paving machine. Deck Placement Going Forward:

46 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Calculating Bid-Well Machine Length: x w x w x w x w x w x w x w x w11-6 SkewWidth+ Extra Machine Length = Width + Extra Length

47 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective

48 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well Limitations: Connections

49 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well Limitations: Crown Break Must be an even truss dimension

50 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well Limitations: Crown Break Must be an even truss dimension

51 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well Limitations: Crown Break Variable

52 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Bid-Well Limitations: Varies 7

53 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Deck Placement:

54 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Deck Placement:

55 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Topics: Typical Deck Forming Typical Overhang Forming Bridge Paving Machine Use of Screed Elevations

56 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Contractor receives a table of screed elevations at quarter points of each span. Deviations in the camber of the beams is normally corrected by varying the haunch height Haunch Setting Grade:

57 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective The haunch height is determined by subtracting the elevation of the top of the beams from the theoretical bottom of the deck The theoretical bottom of the deck is determined by subtracting the thickness of the deck from the given screed rail elevations Screed Elevation Deck Thickness Top of Beam Theoretical Bottom of Deck Setting Grade:

58 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Example of a haunch height or fill table Setting Grade:

59 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Cups or Saddles Rails Setting Grade: Grade must be set by instrument

60 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Check deck thickness and concrete cover over reinforcing steel ** Make sure bridge paving rails are secure with no deflection Dry Run Make sure bridge paving machine is functioning properly

61 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Contractor can only make adjustments for deflections due to the finishing machine weight (not the concrete dead load) Dry Run Contractor assumes deflections due to concrete dead loads have been addressed in the screed elevations provided

62 The State of Practice for Highly Skewed Bridges Deck Issues: Construction Perspective Questions to: Questions ??


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