Year of Publication

2016

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department

Civil Engineering

First Advisor

Dr. Issam E. Harik

Abstract

Wrapping reinforced concrete (RC) columns with Fiber Reinforced Polymer (FRP) composites is effective in increasing their capacity. The current state of art concentrates primarily on fully wrapped RC columns and few studies dealt with partially wrapped columns. The majority of the studies did not account for the influence of the existing steel reinforcement on the column’s behavior. Other studies estimated the total confinement pressure as the sum of the confinement pressure due to the external FRP jacketing and due to the internal transverse steel reinforcement. Few models dealt with the coupled effect of the confinement from steel and partial FRP wrapping of RC columns. The objective herein is to evaluate the effectiveness of partial wraps (or strips) and to develop a confined concrete compressive stress-strain (fc – εc) model that accounts for partial wrapping. Three dimensional finite element (FE) models are generated to evaluate the influence of different parameters on the behavior of concentrically loaded RC circular columns that are partially and fully wrapped with FRP. The influence of FRP volumetric ratio, concrete compressive strength, transverse steel reinforcement ratio, longitudinal steel reinforcement ratio, and strip arrangement, are evaluated. The results indicated an increase in ductility as the number of FRP strips was increased, and showed that longitudinal steel had little influence on the confined fc – εc relationship. The proposed fc – εc model, derived from the parametric study, accounts for the effect of partial and full confinement, the unconfined concrete strength fc, and yielding of transverse steel. Comparison of the results generated using the proposed model with FE and experimental results are in good agreement. The finite element method (FEM) is also used to evaluate the effectiveness of RC columns, wrapped with carbon FRP, subjected to an eccentric load, with a case study of a bridge column wrapped with FRP.

Digital Object Identifier (DOI)

http://dx.doi.org/10.13023/ETD.2016.124

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