Title:
Seismic FRP Retrofit of Bond-Critical Regions in Circular RC Columns: Validation of Proposed Design Methods
Author(s):
Mohamed H. Harajli and Zeinab Khalil
Publication:
Structural Journal
Volume:
105
Issue:
6
Appears on pages(s):
760-769
Keywords:
bond strength; cyclic load; fiber-reinforced polymer; seismic retrofit.
DOI:
10.14359/20104
Date:
11/1/2008
Abstract:
A general expression was derived for designing the thickness of external fiber-reinforced polymer (FRP) jackets required for bond strengthening of spliced reinforcement within the critical hinging region of reinforced concrete (RC) columns. The reliability of the expression has been verified against recent experimental data of rectangular column sections. The objective of the current investigation is to evaluate the application of the corresponding design expression for circular column sections compared with other design methods proposed in the literature. Full-scale circular columns with spliced reinforcement were tested under lateral load reversals. It was found that the mechanism by which the FRP confinement improves the bond strength of spliced bars in circular columns is similar to that in rectangular columns. All of the unconfined columns suffered premature splitting bond failure leading to almost total strength and stiffness degradation. Confining the splice zone with external FRP jackets within the range of thicknesses predicted by the proposed design expression under evaluation lead to a substantial improvement in seismic performance.