1. Reconstruction of the Eads Bridge Highway Deck
Michael J. Cronin, PE, SE

2. Eads Bridge History Opened to traffic July 4, 1874
Designed and planned by James Buchanan Eads
Underwater salvage expert
Shipbuilder
No formal education
Hired by the St. Louis and Illinois Bridge Company as engineer-in-chief for this project

3. Eads Bridge History Design and construction innovations
deep pressurized caisson construction

5. Eads Bridge History Design and construction innovations
deep pressurized caisson construction
high strength cast steel

8. Eads Bridge History Design and construction innovations
deep pressurized caisson construction
high strength cast steel
design of components to permit ease of replacement

10. Eads Bridge History Design and construction innovations
deep pressurized caisson construction
high strength cast steel
design of components to permit ease of replacement
cantilever construction of main arch spans

12. Eads Bridge History Design and construction innovations
Deep pressurized caisson construction
high strength cast steel
design of components to permit ease of replacement
cantilever construction of main arch spans
500 ft spans were 200 ft longer than any built previously

13. Bridge Ownership History
Illinois and St Louis Bridge Company
Missouri Pacific Railroad Company
Terminal Railroad Association
City of St. Louis / Bi-State Development Agency

14. Rehabilitation Challenges
Preserve historically important aesthetic elements
Use existing substructure to support new highway deck
Maintain light rail traffic during construction

15. New Cross Section Four 11 ft lanes designed for HS-20 loading
1 ft offset between outside lanes and the Jersey barriers
5 ft sidewalk on south side of roadway

17. Bridge Sections West Approach West Arcade Main Spans East Arcade
East Approach

19. West Approach & East Arcade
Substructure: 3 longitudinal walls
Outside walls of stone or brick masonry, original construction
Center wall of minimally reinforce concrete, constructed in the 1920’s
Substructure repairs
Tuckpointing
Crack repair
Reinforced concrete pads

24. West Approach & East Arcade
Longitudinal concrete beams over First and Second Streets
Spalled and cracked
Some section loss in reinforcing
Capacity found to be marginally acceptable
Repairs
fiber composite wrap
total replacement

27. West Approach & East Arcade
Existing superstructure: transverse concrete floorbeams with distinctive sloped ends
Replaced with prestressed concrete I girders with special ends
designed as 2 span continuous to maintain distribution to supporting walls
Precast SIP form panels utilized

31. West Arcade Substructure: 2 longitudinal walls
East portion - stone masonry arches in fairly good condition
concrete infill used to strengthen arches
West portion - reinforced concrete open arches in poor condition
total replacement with new reinforced concrete arches

34. West Arcade Existing superstructure
non-composite rolled beams at 4 ft spacing
deck replaced in early 1980’s
design called for cleaning & painting beams, scarifying & overlaying deck
Change order proposed by contractor
total replacement of superstructure with composite rolled beams at 8.5 ft spacing

37. Main Spans
Existing substructure - 2 piers and 2 abutments founded on bedrock
Good condition
Top surfaces of piers and abutments required crack repair and resurfacing

40. Main Spans Arch truss superstructure
no retrofit required if dead load from new floor system and deck is held < 116 psf

41. Main Span Floor System
Existing floor system: half-filled grid deck on floorbeams at 6 ft spacing
New floor system eliminated floorbeams between columns - 12 ft spacing
Exodermic™ Deck specified to span the 12 ft between floorbeams
74 psf using standard weight aggregate

42. Main Span Floor System
The Exodermic™ deck, or an “unfilled steel grid deck composite with a ±4.5” reinforced concrete slab” provides:
Light weight
Structural efficiency
Protection of Light Rail operating below

43. ExodermicTM Bridge Deck

46. Special Main Span Features
Overlook areas at piers and abutments
Bridge can be closed to traffic for special weekend events
Electrical outlets built into north barrier

48. East Approach
10 spans of new steel superstructure on new concrete substructure ft
Highway deck starts above MetroLink track and end below
Highway deck had to be built around MetroLink bridge and elevated station as well as abandoned foundations

49. East Approach Drilled shaft construction one shaft per pier
up to 7 ft in diameter
utilized to minimize footprint and to avoid vibrating adjacent MetroLink foundation

53. East Approach Steel straddle bents transverse beams
support the highway deck over the MetroLink tracks and elevated station platform where traditional supports cannot be used

56. Connection to MetroLink
Handicap accessible ramp built to connect sidewalk to East Riverfront Station

58. Reopening - July 4, 2003

59. THANK YOU