Civil Engineering Association

Problem Statement
Fiber-wrapping offers a -high strength, low weight, and corrosion-resistant jacket which can be easily and quickly installed with negligible increase in the column's cross-section. Since the first application of fiber-wrapping technique to concrete chimneys in Japan (Katsumata and Yagi 1990), there has been an abundance of studies on the use of this technique. It has been put into practice in several states including California, Nevada, New York, and Vermont. Both carbon and glass fibers have been utilized, although carbon fibers are more expensive.
Since use of fiber composites for confinement of concrete is relatively new, theoretical work in this area is limited to the models that were originally developed for transverse steel reinforcement. However, it has been shown that concrete behaves very differently when confined by elasto-plastic materials such as steel as compared to linearly elastic materials such as fiber composites (Mirmiran and Shahawy 1997a). Applying the same models to fiber-wrapped concrete may result in overestimating the strength and unsafe design. In the absence of reliable models, construction industry may be forced to either avoid the use of advanced composites, or to incorporate high "factors of safety," making composite construction less economical. The PI has previously developed such a model for glass-wrapped concrete columns (Mirmiran 1997a&b). There is a need to extend the work to carbon-wrapped concrete columns.

Objectives
The objectives of this study were as follows:
1. Investigate the behavior of carbon-wrapped concrete specimens in uniaxial compression, based on the tests previously conducted by the Florida Department of Transportation.
2. Compare the experimental results with the confinement model of Samaan, Mirmiran and Shahawy (1998) which was developed for concrete-filled E-glass FRP tubes.
3. Compare the experimental results with a non-associative Drucker-Prager type plasticity model using the finite element analysis.