Title: Long Cantilever Columns Subject to Long Cantilever Columns Subject to Lateral Forces Lateral Forces

Author(s): John E. Breen and Phil M. Ferguson

Publication: Journal Proceedings

Volume: 66

Issue: 11

Appears on pages(s): 884-893

Keywords: bending moments; bridge piers; columns (supports) ; deflections; interaction diagrams: lateraI pressure; long columns; models: moving loads; reinforced concrete; research; slenderness ratio.

DOI: 10.14359/7436

Date: 11/1/1969

Abstract:
Ten model cantilever concrete columns approximately 4 x 6 in. in cross section, with strengths varying from 20 to I20 in., were tested to failure under vertical load combined with a horizontal force. Two failed in compression, four in tension, and four from member instability. For h/f ratios of 5 and 10, agreement with the AASHO and ACI column reduction factors was qood. For h/f ratios of 20 and above, the strengths exceeded the Code values considerably. For h/ratios of 25 or more, service load deflections rather than ultimate strengths would control. Instability associated with creep (or microcracking) of concrete in tension just prior to initial cracking was critical for moderate eccentricities (e/f about 0.3) when h/f was 20 or more, but no instability occurred at e/f of 0.6 to 0.9. Computer analyses usually checked these test results within 3 percent and were reasonably agreement with 24 long columns tests by Gehler and Hutter.