Km. Eldash et Sh. Ahmad, A MODEL FOR STRESS-STRAIN RELATIONSHIP OF SPIRALLY CONFINED NORMAL AND HIGH-STRENGTH CONCRETE COLUMNS, Magazine of Concrete Research, 47(171), 1995, pp. 177-184
An analytical model is developed to predict the complete stress-strain
relationship of normal and high-strength concrete subject to uniaxial
compressive loading and confined by transverse reinforcement. The con
finement pressure is assumed to be uniform within the core of the colu
mn. The internal force equilibrium, the properties of the materials, a
nd the geometry of the section are used to evaluate the pressure. The
model utilizes a single fractional equation which satisfies realistic
behaviour of the ascending portion, the peak point, and the post-peak
descending portion of the stress-strain relationship. The predictions
of the model and the available experimental results are compared over
a range of concrete strengths. The model shows good predictive capabil
ity and is applicable for a wide range of variables such as the diamet
er of the circular section, the pitch, diameter and yield stress of th
e spiral, and the volumetric ratio of lateral reinforcement.