UBC Theses and Dissertations
Slenderness effects in prestressed concrete columns Alcock, William John
The purpose of this investigation was to compare the behaviour of real prestressed concrete columns to the predictions of a mathematical model. A previously developed computer programme, based on the mathematical model, had suggested several problems which needed examination. The programme indicated that, in some circumstances, an unstable equilibrium configuration could occur. The existence of this unstable loading path meant that a snap-through type of buckling was a possibility. To check these hypotheses, six T-shaped prestressed concrete columns were constructed and tested at the University of British Columbia. In most instances, experimental observations closely matched the predictions of the mathematical model. The computed and observed peak loads compared well and the presence of an unstable equilibrium path was confirmed. Unfortunately, attempts to measure curvatures and to compare them with mathematically obtained values were unsuccessful. No satisfactory explanation for this problem was found. Having established the validity of the mathematical model through the experimental programme, an examination of snap- — through buckling was made. It was concluded that prestressed concrete columns are not prone to snap-through buckling, although sufficient additional energy applied to a column might result in a jump from a stable equilibrium configuration to an unstable one.
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