Using carbon fiber reinforced polymer grids as confinement reinforcement for concrete

Prestressed concrete piles are widely used in marine environments to support docks, piers, bridges and other waterfront structures. Corrosion of the reinforcement caused by the penetration of the sea salts through the concrete can cause severe deterioration. Corrosion eventually forces replacement of the pile and the structure it supports.; Carbon fiber reinforced polymer (CFRP) reinforcement has been researched for a number of years as a potential replacement for steel reinforcement. The significant advantage that CFRP reinforcement holds over steel is that it is highly resistant to deterioration in a harsh marine environment. One of the primary reasons, however, that the CFRP reinforcement has not seen wider use is its lack of ductility.; Rather than attempting to improve the CFRP ductility, which is very difficult to do, the primary focus of the research reported in this dissertation was to improve the member flexural ductility by confining the concrete in the compression zone. For that purpose a CFRP grid has been investigated for use as confinement reinforcement in FRP reinforced concrete members.; The grid was used in different configurations to confine concrete in the compression zone and improve flexural member ductility. The grid was used to confine concrete cylinders that were tested in axial compression. The results showed a significant increase in the ultimate axial strain of the CFRP confined concrete of approximately 100%. Another application of the grid was the embedment of grid tubes in the compression zone of beams that resulted in an improvement of the ductility factors of approximately 20%. The grid was also used to fully wrap concrete piles that were cast in place or spun cast. The ductility of the piles was improved by as much as 20%.; Therefore improvement of the member flexural ductility by confining the concrete in the compression zone is feasible. However the improvement in the ductility of the concrete elements was not enough to compare favorably with the ductility of steel reinforced concrete member. More improvement is required for the FRP reinforced members to be accepted and used to replace steel reinforced members.