AISC COLUMN DESIGN LOGIC MAKES SENSE FOR COMPOSITE COLUMNS TOO.

Abstract

Results from tests of 37 eccentrically loaded steel tubes filled with concrete were compared with strength estimates. Specimen characteristics and computed strength values are given. The reported flexural capacities include slenderness effects, and no moment magnification would be appropriate for these filled tube specimens. The axial capacity was estimated. The logic of the AISC Specification can be applied to composite columns that are loaded in either direct or eccentric compression. The proposed relationships for an effective yield strength, material stiffness, and cross-section stiffness, will provide for margins of safety generally larger than those resulting from the AISC column design rules applied to steel alone. The AISC beam-column equations likewise provide a reliable index of capacity.