Title:
Confined Concrete Columns Subjected to Axial Load, Cyclic Shear, and Cyclic Flexure—Part II: Experimental Program
Author(s):
Nathan C. Gould and Thomas G. Harmon
Publication:
Structural Journal
Volume:
99
Issue:
1
Appears on pages(s):
42-50
Keywords:
column; confined concrete; fatigue; reinforced concrete; shear strength.
DOI:
10.14359/11034
Date:
1/1/2002
Abstract:
Confined circular concrete columns were tested under cyclic loading to assess the efficacy of a constitutive model for confined concrete and a moment curvature model for confined concrete columns, both of which were discussed in Part I. The columns were fabricated by filling fiber-reinforced plastic (FRP) tubes with concrete. Test variables included axial load, fiber volume ratio of the FRP wrap, and column length. Failure modes that were observed included fracture of the composite wrap, fracture of the steel reinforcement, shear sliding at the column base, and column instability. The results of this test program were used to further the development of the series of models to include the effect of shear on wrap strain and the ability to predict the force displacement relationship for a column subjected to constant axial load and cyclic shear load. A diagonal crack shear model was developed to include the effect of shear force on the prediction of wrap strains. A force displacement model, which includes a base rotation model that accounts for bond/slip, was necessary for the prediction of stability and ductility of a confined column. The reliability of each of these new models is discussed. Additionally, the experimental and analytical results from Parts I and II are used to evaluate assumptions inherent to current design guidelines.