Reconstruction of the Eads
Bridge Highway Deck
Michael J. Cronin, PE, SE
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
Eads Bridge History
 Design and construction innovations
 deep pressurized caisson construction
Eads Bridge History
 Design and construction innovations
 deep pressurized caisson construction
 high strength cast steel
Eads Bridge History
 Design and construction innovations
 deep pressurized caisson construction
 high strength cast steel
 design of components to permit ease of
replacement
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
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
Bridge Ownership History
 Illinois and St Louis Bridge Company
 Missouri Pacific Railroad Company
 Terminal Railroad Association
 City of St. Louis / Bi-State Development Agency
Rehabilitation Challenges
 Preserve historically important aesthetic elements
 Use existing substructure to support new highway

deck
Maintain light rail traffic during construction
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
Bridge Sections
 West Approach
 West Arcade
 Main Spans
 East Arcade
 East Approach
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
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
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
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
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
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
Main Spans
 Arch truss superstructure
 no retrofit required if dead load from new floor
system and deck is held < 116 psf
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
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
ExodermicTM Bridge Deck
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
East Approach
 10 spans of new steel superstructure on new


concrete substructure - 1000 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
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
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
Connection to MetroLink
 Handicap accessible ramp built to connect
sidewalk to East Riverfront Station
Reopening - July 4, 2003
THANK YOU