BEHAVIOR OF CONCRETE SPECIMENS REINFORCED WITH COMPOSITE MATERIALS - LABORATORY STUDY

The world's infrastructure continues to age and deteriorate. Forty percent of the nation's 575,000 bridges are structurally deficient or structurally obsolete, and 25% are over 50 years old. Many older bridges were designed for lower traffic volumes and lighter loads than what are common today. External post-tensioning and epoxy-bonded steel plates are the strategies commonly used to upgrade deficient structures. However, fiber reinforced polymer (FRP) composites are also starting to be used for strengthening. The main objective of this study was to investigate the interaction between FRP composite and concrete by addressing the most important variables in terms of FRP properties. Type of fibers, thickness of the laminates, fiber orientation and FRP strengthening configuration were studied while keeping the type of concrete, steel reinforcement and geometry of the samples constant. The intent of the data collection and analysis was to gather extensive information on the performance of FRP-reinforced concrete, rather than to investigate the structural behavior of FRP-reinforced members. Appearance of first crack on the concrete, ultimate loads and the corresponding strains and deflection, and the failure modes were of main interest. The FRP systems included in this study were most of those known to be currently available. In addition, two customized FRP systems were developed using only domestically available materials. All systems were tested under nearly identical conditions with respect to concrete strength, specimen dimensions, reinforcement, surface preparation, test methods, and analysis. The ultimate strength increase at failure ranged from 18 to 545%, depending upon the FRP-application scheme. The specimens showed no significant increase in stiffness prior to initial cracking of the concrete. The FRP-strengthened specimens exhibited greater deflections prior to initial cracking of the concrete. Following initial cracking, the behavior of the specimens was mostly influenced by the properties of the FRP laminate. The results showed that the increase of the load-carrying capacity and the performance of the FRP-reinforced beams were strongly dependent on the FRP configuration. The failure modes showed dependency on the stiffness and strength of the FRP reinforcement and scheme used to strengthen them. The study suggested that the effectiveness of the FRP composite decreases as the rigidity (elastic modulus x FRP thickness) of the laminates increases.

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• Record URL:
  https://rosap.ntl.bts.gov/view/dot/14410
• Corporate Authors:

  Oregon State University, Corvallis

  Department of Civil, Construction and Environmental Engineering
  Corvallis, OR  United States  97331

  Oregon Department of Transportation

  Research Section, 200 Hawthorne Avenue, SE, Suite B-240
  Salem, OR  United States  97301-5192

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Kachlakev, D I
  • Green, B K
  • Barnes, W A
• Publication Date: 2000-2

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 180 p.

Subject/Index Terms

• TRT Terms: Bearing capacity; Composite materials; Cracking; Deflection; Failure analysis; Fiber reinforced plastics; Fiber reinforced polymers; Laboratory tests; Laminates; Reinforced concrete; Specimens; Stiffness; Strain (Mechanics); Structural strengthening; Ultimate strength
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 00791466
• Record Type: Publication
• Report/Paper Numbers: FHWA-OR-RD-00-10,, Final Report
• Contract Numbers: SPR 387
• Files: NTL, TRIS, ATRI, USDOT, STATEDOT
• Created Date: Apr 3 2000 12:00AM