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Tom Hoffman, P.E.
R-1 Structures Engineer
STRUCTURAL ISSUES
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BRIDGE STATISTICS
BRIDGE IDENTIFICATION NUMBER: 5521180
AGE: Built in 1929
LENGTH: 14 spans,
2,184 feet ROADWAY WIDTH: 26.1 feet
STRUCTURE TYPE: Combination of thru truss, decktruss, and deck plate girders
BIKE / PED ACCOMMODATIONS: None
VERTICAL CLEARANCE ON BRIDGE: 14 feet
MAX VERTICAL CLEARANCE OVER WATER: 95 feet
AVERAGE ANNUALDAILY TAFFIC (2008): 3,150 vehicles per day
WEIGHT CAPACITY: -Restricted since 1994 to
less than 102,000 pounds.-Currently reduced to a singlelane/ 40 ton posting.
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RECENT WORK HISTORY
1990-91 Bridge Rehabil itat ion ProjectAppx $7.0 million in 1989 (Appx. $17.3 in 2007 dollars) Bearings - Some Cleaned, Some Replaced Spot Painting (Span 4-9, bearings)
Deck Replacement With Lightweight System Floor Beam Replacement and Strengthening (some spans) Joint Replacement Bridge Rail
Approach Slab Replacement Concrete Repairs on Piers and Abutments Pier 4 Compression Straps Added (Now occur on Piers 4-8)
-The first strapped in 1974 to arrest crack development
Emergency Repair Contract Compression Band Replacement - $125,000 in 2005
Pier Repairs - $100,000 in 2008
Steel Repairs - $1 m illion estimated in 2009 Maintenance Repair of Bridge Joints 2005, 2006, 2008
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INITIAL PROBLEM IDENTIFICATION
Bridge Condition Rating
Score 3.375 out of a possible 7 points (2009) Scores between 3 and 4 indicate serious deterioration or not
functioning as originally designed Problems are with main carrying members, bearings, joints,
concrete, paint, and wearing surface
Federal Sufficiency Rating
Score 29.2 (2008) out of a possible 100 points Scores less than 65 qualify for Federal funding
Load Restricted
40 Ton limit restricts all overloads, including log trucks and milktrucks
Limited roadw ay vertical clearance of 14-0 Trucks in excess of 14 have struck the bridge on several
occasions, requiring the bridge to be closed for repair
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Truss Terminology
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Channel Piers
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Concrete CompressionStrap Replacement
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Concrete Deterioration
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Concrete DeteriorationPier 3- Before
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Concrete DeteriorationPier 3- After
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Pier 8 Condition(Before)
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Pier 8 Condition
(After)
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Steel and Paint Condition
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Steel and Paint Condition
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Joints
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Bearings
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Recent Repairs-Floorbeams Pier 5 and 8
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Recent Repairs-Bottom Chord
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Recent Repairs-Bottom Chord
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Recent Repairs-Steel Pier
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Recent Repairs-Steel Pier
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Recent Repairs-Gusset Plates
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Other Yellow Flags
Many yellow flags for gussets and strap ties are not being addressedat this time. All red flags, and yellow flags of significance are being
repaired.
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What Now?
1) Paint of Select Areas Some areas are beingblasted and painted to slow deterioration ofcritical areas.
2) Finish Chord Repairs
3) Finish Floorbeam Repairs and Add Troughs
4) Re-Inspect in the Spring Repair as Needed
5) Possibly Paint Selected Truss Members and underJoint Areas
-Chords of Spans 4, 5 and 9- Entire Truss of Spans 6 and span 8,
span 7 (splash zone down)- Under Joint Areas at Piers 3, 5 and 8
- Estimated at $6 Mil lion
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General Questions .
1) Why w as the load posting reduced?
2) What does it mean?
3) Does a single lane really make things better?
4) $64,000 question .Is the bridge safe?
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Questions????