Strengthening of Concrete Beams With Fasteners and Composite Material Strips-Scaling and Anchorage Issues
Abstract
A system to rapidly strengthen concrete beams and slabs, known as the Mechanically-Fastened Fiber-Reinforced Polymer (MF-FRP) system, has been developed. In the fourth year of research on the subject, the focus was on scaling and anchorage issues. The effect of increasing the number of strips, the fastener spacing, termination distances, and the use of expansion anchors at the strip ends were considered. The scaling study also investigated the use of the MF-FRP system on a full-scale highway bridge. A second series of tests was conducted on large-scale T-beams at the U.S. Army Engineer Research and Development Center, Vicksburg, MS, in the summer of 2002. The results of this testing and of parametric design studies conducted were used to design the strengthening system for a flat-slab bridge built in 1930 in the city of Edgerton, WI, and slated for replacement in 2003. The bridge was strengthened with the MF-FRP system in the summer of 2002 and tested to failure in the summer of 2003. An investigation was also conducted into the properties of the FRP strips with different constituent material properties. An optimal strip design to produce the best ultimate longitudinal strength and stiffness, as well as bearing strength, has been recommended to the manufacturer. The research conducted revealed a number of important scaling related issues with the MF-FRP system. It was found that multiple strips were not as effective as single strips, that a double row of fasteners at 2 inches on center is less effective than a single row of fasteners at 3 inches on center; and that mechanical anchor bolts at the ends of the strip significantly improved performance and delayed the onset of end delamination failures. The importance of a small termination distance from the support was confirmed in testing. Fatigue testing to 2 million cycles showed no degradation of the MF-FRP strengthening system. The full-scale bridge application proved the versatility of the system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2004
- Accession Number
- ADA426411
Entities
People
- Anthony J. Lamanna
- David T. Borowicz
- Dushyant Arora
- Gerardo I. Velazquez
- Lawrence C. Bank
Organizations
- Engineer Research and Development Center