Title: Elastic Frame Analysis-Corrections Necessary Design of Short Concrete Columns in Braced Framers

Author(s): Hajime Okamura, Shriniwas N. Pavay, John E. Breen and Phil M. Ferguson

Publication: Journal Proceedings

Volume: 67

Issue: 11

Appears on pages(s): 894-897

Keywords: bending moments; columns (supports); eccentricity; frma analysis; rienforced concrete; short columns; structural design.

DOI: 10.14359/7320

Date: 11/1/1970

Abstract:
Ordinary frame analysis based on gross concrete sections generally leads to computed column mombert s and eccentricities at ultimate considerable in error (generally on the unsafe side) because of (1) the lower stiffness of the craxcked beam, (2) the loss of stiffness of th column concrete near ultimate, and (3) sometimes the yeilding of column compression steel on one face. Short columns in single curvatur in braced froames, analyzed by a computer procedure, show indicated eccentricities ranging from .52 to 2.08 times the nominal values obtained from ordinary moment distribution. Moment distribution procedures based on radical changes in calculated member stiffness are indicated as feasible and empirical corrections are also presented for columns in braced frames.