Title:
Renewed Assessment of Creep and Shrinkage Effects in
Reinforced Concrete Beams
Author(s):
Raed M. Samra
Publication:
Structural Journal
Volume:
94
Issue:
6
Appears on pages(s):
745-751
Keywords:
beam; creep; deflection; long-term; model; reinforced (con-crete);
shrinkage; steel; strain; stress; time-dependent.
DOI:
10.14359/9734
Date:
11/1/1997
Abstract:
A creep model is proposed which involves the use of an enhanced iterative procedure that converges quickly, within 2-4 cycles. The model provides information on varying concrete and steel stresses and strains with time, as well as beam curvatures and dejections. The effects of shrinkage are added by considering another model which has been tested and documented in the literature. The creep model, which is useful in the analysis of singly reinforced beams, combines a rational approach, based on mechanics and the principles of equilibrium, stress-strain relationship and compatibility, with creep data, expressed in terms of a creep factor which reflects the contribution of the major variables affecting creep, such as ambient relative humidity, age at loading, time under load, volume to surface ratio, etc. The calculated deflections using the approach of the paper are compared with measured values reported by Washa and Fluck (I 956), Bakoss et al. (1982) and Pulmano and Shin (1987). The correlation between calculated and measured deflections is very good.