US 84 Mississippi River Bridge

Transcription

1 US 84 Mississippi River Bridge U29 And U49 Pin and Link Replacement James Gregg, PE HNTB Project Manager

2 Quick Facts WPA Project #1126 Constructed 1940 Built for: City of Natchez Total Cost $3,562, Substructure: Dravo Corp. Superstructure: Bethlehem Steel Designed by: Ash-Howard- Needles &Tammen (HNTB) Emmanuel Howard designed toll facility (H in HNTB) 2

3 Location of Pins Link and Pin Anchor Arm Quasi-Suspended Spans Suspended Span Anchor Arm 3

4 Location of Lower Pins 10 f Upper Pin (Upper pin is longer than lower pin) 10 x 16 x 7-6 Link 10 f Lower Pin 4

5 U49 Lower Pin U49 Upper Pin U49 Lower Pin 5

6 U29 Downstream Truss (Upstream Side) East West Rotated 2 ¾ (Ave.) 6

7 U29 Downstream Truss (Downstream Side) West East Rotated 2 ¾ (Ave.) 7

8 U49 Upstream Truss (Upstream Side) East West Not measured (Ave.) 8

9 U49 Upstream Truss (Downstream Side) West East Not measured (Ave.) 9

10 Pin Rehabilitation Options Considered 4 options (Option 4 chosen) Option 1 Restrain and Monitor Low cost option that is less intrusive Option 2 Reset Pins Repeat of the 1996 attempt Option 3 Replace Pin Replace lower pin but not link Option 4 Replace Lower and Upper Pins and Links Remove and replace existing pin with new pin and retainer plate Option Chosen by MDOT and Louisiana DOTD 10

11 Pin Rehabilitation Option 4 Replace Link and Pins Cantilever Span Suspended Span C T Zero Force Member 11

12 Pin Rehabilitation Option 4 Replace Link and Pins Cantilever Span Splice Plate Suspended Span Upper Longitudinal Restraint Diagonal Bypass Lower Longitudinal Restraint Bypass Load Path A (Diagonal Bypass) 12

13 Pin Rehabilitation Option 4 Replace Link and Pins Cantilever Span Suspended Span Shims Bypass Load Path B (False Chord/ Top Chord) 13

14 Pin Rehabilitation Option 4 Replace Link and Pins Cantilever Span Suspended Span Splice Plate Bypass Load Path C (Slice Plate) 14

15 US 84 Mississippi River Bridge Construction Request for construction qualifications MDOT shortlisted 2 qualified contractors Awarded to low bid Contract award date: November 2014 Contract amount: $3.8 M Selected contractor: CEC Bridge closed to traffic for 11 weeks Traffic put head to head on new bridge 15

16 Pin Rehabilitation Option 4 Sequence of Construction 1. Tension Diagonal Bypass Propose: Remove and bypass load on link and diagonal U49 Tensioned diagonal bypass to 836 kips L48-U49 D = 850 kips DL in member 761 kips (Tension) Link D = 660 kips DL in member = 655 kips (Tension) 16

17 Pin Rehabilitation Option 4 Sequence of Construction 2. Tension Upper Longitudinal Restraints Purpose: Prevent thermal/ longitudinal movement in truss Truss pin side being replaced Tensioned to 80 kips Diagonal bypass also has horizontal component Opposite side Tensioned to 180 kips 40 degree temperature drop from installation 17

18 Pin Rehabilitation Option 4 Sequence of Construction 3. Weld Templates for Splice Plate Purpose: Allow contractor to field drill splice plate 18

19 Pin Rehabilitation Option 4 Sequence of Construction 4. Field Drill and Install Splice Plate Purpose: lock joint from moving, secondary bypass, alternate load path U49 U /8 f A490 bolts 300-7/8 f A490 bolts 19

20 Pin Rehabilitation Option 4 Sequence of Construction 5. Install Top Strut Plates Purpose: Provide additional lateral resistance between cantilever and suspended span truss 20

21 Pin Rehabilitation Option 4 Sequence of Construction 6. Tension Lower Longitudinal Restraints Purpose: secondary load path 21

22 Pin Rehabilitation Option 4 Sequence of Construction 7. Cut Pins Cut four faces of pin 1.5 hrs per face of pin 1 full day of cutting 22

23 Pin Rehabilitation Option 4 Sequence of Construction 7. Cut Pins kip D in link when pins were cut Remaining load transferred to splice plate 1.0 to 3.0 increase in stress in splice plate when pin was cut 23

24 Pin Rehabilitation Option 4 Sequence of Construction 7. Cut Pins 24

25 Pin Rehabilitation Option 4 Sequence of Construction 8. Remove Link 25

26 Pin Rehabilitation Option 4 Sequence of Construction 9. Install and Temporarily Fasten New Eyebars Purpose: field drill holes and temporarily support new eyebars 26

27 Pin Rehabilitation Option 4 Sequence of Construction 10. Line Bore new upper and lower pin hole New Pins bored level and plumb to each other 24 hr set up and measure 30 hrs of cutting 27

28 Pin Rehabilitation Option 4 Sequence of Construction 11. Install New Pins Pins packed in dry ice No problems installing pins 28

29 Pin Rehabilitation Option 4 Sequence of Construction 12. Install New Retainer Plate 29

30 30 US 84 Mississippi River Bridge Pin And Link Replacement

31 Pin Rehabilitation Lessons Learned EXISTING PIN MISSALIGNMENT 31

32 Pin Rehabilitation Lessons Learned (U49) Existing and New Pins Existing upper pin was off at 3 / 16 per foot Inboard high side Existing lower pin was plumb Plan was to use upper pin and lower pin Upper pin was not large enough Used lower pin from U29 for U49 upper pin U29 pins were left at stock length and turned down after boring Inboard gusset Outboard gusset 32

33 U49 Lower Gusset Walked 33

34 Pin Rehabilitation U49 Lessons Learned Lower Pin Gusset Lower pin inboard and outboard gussets walked out 1/2" New pin did not stick out as much as expected Inside washers were not flush between link and gusset 34

35 Pin Rehabilitation Lessons Learned Lower Pin Gusset Provide additional brace on U29 lower pin gusset to avoid walking Modified sequence of construction Leave lower blocking shims out when tensioning diagonal bypass No walking observed 35

36 Pin Rehabilitation U29 Lessons Learned U29 Truss Shift 36

37 Pin Rehabilitation Lessons Learned Cantilever Truss is Shifted 37

38 Pin Rehabilitation Lessons Learned Cantilever Truss is Shifted Suspended span cantilevered out. Final tie in was at U29 L29 38

39 Pin Rehabilitation Lessons Learned Existing Pins and Gusset Existing upper pin was not plumb Existing lower pin was close to plumb Gussets were not plumb Inboard gusset Outboard gusset 39

40 Pin Rehabilitation Lessons Learned Cantilever Truss is Shifted A490 splice plate bolts were not designed to handle of bending Add 100 additional A490 bolts in splice plate Install bracing plate 40

41 Pin Rehabilitation Lessons Learned Cantilever Truss is Shifted 41

42 Pin Rehabilitation Strain Gauges 42

43 Pin Rehabilitation U29 Lessons Learned Splice Plate Max Stresses (U29) Inboard Gusset Side 1 Stress, ksi Side 2 Stress, ksi Vertical Gage deg Gage Horizontal Gage Outboard Gusset Side 1 Stress, ksi Side 2 Stress, ksi Vertical Gage deg Gage Horizontal Gage

44 Pin Rehabilitation U29 Lessons Learned 44

45 Pin Rehabilitation Lessons Learned (New Eyebar Loads) U49 Inboard link is 17% greater than outboard link Bar 1: kips (inboard) Bar 2: kips Bar 3: kips Bar 4: kips Bar 5: kips Bar6: kips (outboard) Total Load = 763 kips Dead Load in 1940 plans: 655 kips Difference: 2.7% U29 Inboard link is 44% greater than outboard link Bar 1: 70.9 kips (inboard) Bar 2: kips Bar 3: kips Bar 4: kips Bar 5: kips Bar6: kips (outboard) Total Load = kips Dead Load in 1940 plans: 638 kips Difference: 2.8% 45

46 US 84 Mississippi River Bridge Pin Rehabilitation Owner: TEAM Mississippi Department of Transportation (lead) Louisiana Department of Transportation and Development Engineer: HNTB Contractor: C.E.C., Inc (prime) Specialty Demolition (sub) In-Place Machine (sub) BDI (sub) 46

47 47 US 84 Mississippi River Bridge Pin Rehabilitation

48 US 84 Mississippi River Bridge Pin Rehabilitation Questions? 48