Slender Prestressed Concrete Columns

The instability of long prestressed concrete columns is investigated both experimentally and theoretically. Tests on 36 slender eccentrically loaded hinged, axially prestressed concrete columns are described and conducted to determine the behavior of the columns in the full range of loading, including post-buckling. The variables investigated are eccentricity, slenderness, and prestress, each at three levels. A computer-oriented theory of nonlinear instability is presented, based on the cotangency criteria and using a finite element approach. Good agreement is shown between experimental and theoretical loads and deformations, both before and in the post-buckling region. The effects of slenderness, eccentricity and prestress are discussed. Future research needs are indicated.