Effect of CFRP bond length on repair of composite steel girders with a cracked flange

ABSTRACT

The results of an experimental study on the repair of artificially damaged steel-concrete composite beams repaired using adhesively bonded carbon fiber-reinforced polymer (CFRP) sheets are presented. Six beams composed of W150x22 steel sections with concrete slabs were tested in four-point bending to evaluate the bond length of CFRP sheets. Five beams had their tension flanges completely cut using a saw at mid span, to simulate a severe damage. CFRP sheets were then used to repair four damaged beams. The number of CFRP layers was kept constant, while the length of the CFRP repair varied from 8 to 97 percent of the span. The repair system was installed symmetrically around the centerline of the beam. Results showed that the induced damage has reduced flexural strength and stiffness by 60 and 54%, respec-tively. However, the strength of the CFRP-repaired beams ranged from 72 to 116% of the origi-nal undamaged strength, depending on bond length. Stiffness was generally recovered, but was not much affected by the bond length. Failure was initiated by debonding of CFRP layers.