Title: Design of Rectangular HSC Columns for Ductility

Author(s): O. Bayrak and S. A. Sheikh

Publication: Symposium Paper

Volume: 213

Issue:

Appears on pages(s): 61-82

Keywords: columns; deformability; ductility; earthquakes; energy dissipation; high-strength concrete (HSC)

DOI: 10.14359/12746

Date: 5/22/2003

Abstract:
In most design codes (1,2,3) provisions for the design of confinement reinforcement contain empirical constants that were based on the experimental data available in the literature. Most of the data used was from tests in which normal strength concrete columns with square cross sections were used. Only recently, a limited amount of experimental data on high strength concrete (HSC) columns bas become available. Experimental data on rectangular HSC column behavior, on the other hand, is rarely found in literature, especially on large size HSC specimens tested under moderate to high axial load levels and subjected to large inelastic displacement excursions. This paper presents results from a continuing research program which aims to study confinement of concrete by lateral reinforcement. The current work deals with the experimental behavior of HSC (52 MPa < fc’< 112 MPa) columns having rectangular cross sections. Large-size columns (250 x 350 x 1473 mm) with heavy stubs (508 x 762 x 813 mm) were tested under moderate to high axial load levels and reversed cyclic displacement excursions. Effects of several variables such as section geometry, axial load level, and amount of lateral reinforcement on the behavior of these specimens are studied, and the responses of the rectangular specimens are compared to those of specimens with square cross sections. It is concluded that HSC columns having square and rectangular cross sections can be designed to behave in a ductile manner, provided that sufficient amount of confinement reinforcement is used in an efficient configuration.