Title:
Long Term Behavior of Prestressed and Partially Prestressed Concrete Beams: Experimental and Numerical Results
Author(s):
Bernard Espion and Pierre Halleux
Publication:
Symposium Paper
Volume:
129
Issue:
Appears on pages(s):
19-38
Keywords:
beams (supports); camber; cracking (fracturing); deflection; creep properties; failure; loads (forces); partial prestressing; prestressed concrete; prestress loss; serviceability; shrinkage; strains; stress analysis; structural design; General
DOI:
10.14359/1321
Date:
12/1/1991
Abstract:
Tests results from long-term experiments on prestressed and partially prestressed concrete beams are reported. Tests were carried out on 10 rectangular beams spanning 2 m and undergoing sustained loading for five years. After that time, there was no evidence of stabilization of the time-dependent behavior of concrete. Numerical modeling of the deformation of the midspan section explains experimental observations and confirms that the presence of ordinary reinforcing steel in a prestressed concrete section leads to a redistribution of stresses between concrete and steel which should be taken into account in serviceability limit-state computations. Tests to failure of the beams at 5 years yield no significant differences in carrying capacity with tests executed at an early age. It is suggested that the deflection limit state is a major consideration in design and that the degree of prestressing should be chosen in function of ratio of permanent load to total design load (permanent and live).