Sh. Ahmad et Mp. Mallare, A COMPARATIVE-STUDY OF MODELS FOR CONFINEMENT OF CONCRETE BY CIRCULARSPIRALS, Magazine of Concrete Research, 46(166), 1994, pp. 49-56
A number of analytical models have been proposed for predicting the st
ress-strain curves of spirally confined concrete. In this Paper the an
alytical models available in the literature for confinement of concret
e by circular spirals are studied, and their predictions are compared
with experimental results reported in the literature. It is concluded
that none of the analytical models could accurately predict the stress
-strain curves for the full range of experimental data considered in t
his study. Most of the models were able to predict the peak strength b
ut failed to predict satisfactorily the associated strain and the stre
ss-strain curves. The stress-strain predictions of some of the models
were adequate for low- and medium-strength concretes, but the models d
emonstrated poor prediction for higher strength (f(c)' > 42 MPa) concr
etes. Some of the models predicted the stress-strain curves better for
concrete confined with lower amounts of spiral confinement (rho(s) <
0.01) than for concrete confined with higher amounts of spiral confine
ment (rho(s) > 0.01). The predictions of the iterative model of Ahmad
and Shah were generally in closest agreement with the experimental res
ults. Since this model utilizes the multiaxial properties of concrete
and employs an interaction between the dilation characteristics of the
concrete core and the spiral confinement, it appears to be the most s
uited to the accommodation of parameters influencing the stress-strain
response of spirally confined concrete.