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July 27, 2011 Salt Lake City, Utah. RAC/TRB Summer Meeting. Shear Repair of P/C Box Beams using CFRP Fabric KYDOT. Kentucky Transportation Center University of Kentucky. Kentucky Transportation Cabinet. Objective.
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July 27, 2011 Salt Lake City, Utah RAC/TRB Summer Meeting Shear Repair of P/C Box Beams using CFRP FabricKYDOT Kentucky Transportation Center University of Kentucky Kentucky Transportation Cabinet
Objective Retrofit P/C Spread Box Beams using carbon fiber reinforced polymer (CFRP) fabric to increase Shear Capacity
CFRP Fabric vs. Steel wCFRP = 0.0051 lb/ft wSteel = 0.19 lb/ft ≈ 37 wCFRP Steel Plate (A36 Steel) hCFRP = 0.0066” CFRP Fabric + Resin hSteel= 0.056” ≈ 8.5 hCFRP 1” 1” Ultimate Load = 3.25 kip
Task #1 Material Testing
Task #2 Beam Testing
Task #3 Field Application
Bridge on KY 3297 over Little Sandy River Carter County, Kentucky Shear Cracks in P/C Box Beams
Severe Shear Cracks Cracks Growing at an Alarming Rate
Original Solution Replace the Superstructure - Cost: ~ $600,000 - Close Bridge to Traffic
Alternate Solution Use CFRP Fabric - Cost: $105,000(Design, Repair, and 3-years Monitoring) - Bridge Remains Open to Traffic
Placement of CFRP Fabric Step 1: Surface Preparation
Placement of CFRP Fabric Step 2: Crack Injection and Filling of Voids
Placement of CFRP Fabric Step 3: Apply Primer
Placement of CFRP Fabric Step 4: Apply Carbon Fabric
Placement of CFRP Fabric Step 5: CFRP Fabric on Outside Face Painted to Match Concrete Color
Task #4 Monitoring
Bridge Monitoring (10/01 to 12/06) Scaffolding Used for Monthly Bridge Monitoring
CFRP Fabric on Inside Faces of the Beams Was Not Painted to Match Concrete Color Crack Monitor
Crack Monitor on Inside Beam Face No Crack Movement Since Repair Was Completed in October 2001
Conclusion Cost Effective: $105,000 for Repair vs. $600,000 for Replacement- Repair is Effective: No Crack Movement Since Repair was Completed in October 2001- No Detour- No Traffic Control- No Traffic Disruption !!!!! HURRAY !!!!!!
The Daily Independent November 2001
Other CFRP Projects in KY • 9 Bridges Strengthened with CFRP • 3 Bridges Strengthened With Steel FRP