STIFFENING OF STEEL STRINGER BRIDGES USING CARBON FIBER REINFORCED POLYMERS (SECOND REVISION)
The process of stiffening steel stringer-concrete deck bridges with a carbon fiber reinforced polymer (CFRP) cover plate was evaluated in this investigation. A carbon composite plate was adhered to the tension side of a steel stringer to form the hybrid component studied herein. An accelerated aging method was developed to evaluate the loss in material and component mechanical properties. A static evaluation of coupon samples was performed to establish the strength and stiffness of the CFRP material. Reductions in mechanical properties after accelerated environmental conditioning were established. The test matrix for the hybrid beams included the use of two structural adhesives for bonding, acrylic versus epoxy; two reinforcement lengths, 2/3 and 1/2 the span length; and two connection types, bonded versus bonded-bolted. The change in moment of inertia of the hybrid beams was evaluated for each parameter of the test matrix. Furthermore, the hybrid beams that were bonded using the acrylic adhesive were conditioned under accelerated aging and the change in moment of inertia of the hybrid beams was evaluated with respect to time. The effects of natural aging were established by exposing a hybrid member to natural weather conditions for two years to provide a correlation between accelerated aging and natural aging. The fatigue response of the hybrid member was evaluated using AASHTO category C guidelines. The strength and stiffness of the CFRP material under bending and tension were established and the maximum reduction in these values after accelerated conditioning was found to be 7%. The aged CFRP material followed a similar trend in that the reduction rate followed a typical inverse exponential curve. An increase in the composite moment of inertia was established with the addition of the CFRP cover plate to the steel stringer of 8.3% and 7.9% depending on the reinforcement length while reductions in these values were found to be 4.3% and 4.02% after 180 days of exposure to accelerated hygrothermal conditioning. Calibration of the accelerated aging method was made with the naturally aged hybrid beam, i.e., two years of natural aging correlated well with 180 days of accelerated conditioning. The composite moments of inertia were not significantly altered by the addition of bolts. Fatigue response of the aged hybrid beams established a maximum 3% reduction in the composite moments of inertia for AASHTO category C fatigue cycling.
- Published October 1997; first revision February 1999; second revision June 2003.
West Virginia University, MorgantownConstructed Facilities Center
Morgantown, WV United States 26506-6101
Charleston, WV United States 25305-0440
Washington, DC United States 20590
- GangaRao, H V S
- Burdine, E B
- Publication Date: 2003-6
- Features: Appendices; Figures; Photos; References; Tables;
- Pagination: 154 p.
- TRT Terms: Accelerated tests; Acrylic resins; Bending; Bolting; Bonding; Bridges; Carbon fibers; Epoxy resins; Fatigue (Mechanics); Fiber reinforced plastics; Inertia (Mechanics); Length; Mechanical properties; Steel; Stiffeners (Plates); Stiffness; Strength of materials; Stringers; Structural connection; Tension
- Uncontrolled Terms: Hybrid beams
- Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;
- Accession Number: 00962810
- Record Type: Publication
- Report/Paper Numbers: WVDOH RP #104,, CFC 97-244A,, Final Report
- Files: TRIS, USDOT, STATEDOT
- Created Date: Sep 8 2003 12:00AM