Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Strengthening a Concrete Slab Bridge Using
Carbon Fiber Reinforced Polymer (CFRP) Composites
Presentation to:
NJDOT Design Summit 2009
By:
Thomas G. Zink, P.E.
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Structurally Deficient – What Does it Mean?
Deck, Superstructure, or Substructure with a
Condition Rating ≤ 4
• Advanced deterioration
• Loss of capacity
Low Inventory Rating
Not necessarily “unsafe”
Requires immediate attention/repair
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Case Study - 19th Ave. Bridge over Salt River Canal
Typical Concrete Slab Bridge
• Constructed 1940’s
• Widened 1960’s
• Three spans
• Five lanes
• ADT = 30,000
Deficient Load Capacity – Should be Posted
Original Concept
• Full Replacement
• $3.5 - $4.5 million
• 10 - 12 months
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Innovative Solution: Strengthen using CFRP Material
Rapid solution was desired
Truesdell/Gannett Fleming Design-Build Team proposes CFRP alternative
Why CFRP materials?
• High strength
• Low density
• Corrosion resistance
• Easily fabricated/shipped
• Jobsite handling
• “Green” alternative
• Speed of installation
• Cost benefit
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
A Two Part Solution
Positive Moment Regions
• Surface bonded CFRP sheets
• SikaWrap Hex 103C
• Two layers of 1’ x 15’ strips
• Spaced at 3’ centers
• High strength adhesive
Negative Moment Regions
• “Near Surface Mount” solution
• 1” x ¾” grooves in slab
• CFRP bars grouted in grooves
• Aslan 200 Bar
• 0.5” diameter (13’ long)
• 63 bars at 10” centers
• ¾” thick polymer overlay
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Design Approach
Inspection
Determine in-situ material properties
• NDT (including GPR)
• Supplemental mild destructive tests
• Coring
Determine existing live load capacity
Compute additional capacity needed
• ACI 440.2R-08:
“Guide for the Design and Construction of Externally Bonded
FRP Systems for Strengthening Concrete Structures”
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Load Rating Comparison
Vehicle
Before Retrofit
After Retrofit
RF
Tons
RF
Tons
HS-20 - IR
0.43
15.6
1.0
36
HS-20 - OR
0.72
26
1.67
60
Rating Factors ≥ 1.0
Load Posting Not Required
CFRP wraps increased (+) flexural capacity by 140%
CFRP rods increased (-) flexural capacity by 80%
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Construction and Instrumentation
Surface preparation key
• Remove deteriorated concrete
• Patch spalls & fill cracks
• Air blast
Vibration control during 48 hr cure
“Smart Structure” Instrumentation
• Strain gauge sensors
• Benchmark tests
• Solar powered wireless data transmission
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Load Test Verification
City owned trucks
Placed to produce
maximum bending
Concrete strain
reduction observed
Testing verified the successful participation of
the CFRP components in resisting live load.
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Bridge Ratings
Cost Savings
Before
Operating
HS-9
(16 tons)
HS-14
(26 tons)
After
$ Millions
Inventory
5
4
3
2
Inventory
Operating
1
HS-20
(36 tons)
HS-33
(60 tons)
0
CFRP
Replace
Advantages of CRFP Strengthening Alternative:
• Construction time: 3 weeks
• Minimal disruption to traffic
• “Green Solution”
• Substantial cost savings
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
CFRP Strengthening Opportunities in New Jersey
6,447 bridges in the State of New Jersey
• Average age: 50 years
• 693 (11%) are “Structurally Deficient”
• 1,504 (23%) are “Functionally Obsolete”
• Deterioration continues
• Much work; limited funding
• “Fix-it-First” approach
Other potential CFRP applications include:
• Pier strengthening
• Culvert strengthening
• Seismic hardening
• Concrete pavement repair
American Council of Engineering Companies
of New Jersey
Design Summit 2009
Innovations in Design, New Technologies & Process Delivery Changes!
Thank You!
Any questions,
please contact:
Tom Zink
(856) 802-9930
American Council of Engineering Companies
of New Jersey