Confinement model for high-strength concrete

A mathematical model is developed to express the stress-strain relationship of high-strength concrete confined by transverse reinforcement. The model is applicable to both normal-strength and high-strength concretes, covering a strength range between 30 and 130 MPa. It incorporates all the relevant parameters of confinement that have been observed to play important roles i n column tests. These parameters include the type, volumetric ratio, spacin g, yield strength, and arrangement of transverse reinforcement as well as c oncrete strength and section geometry. Therefore, it can be used for concre te confined by spirals, rectilinear hoops, crossties, welded wire fabric, a nd combinations of these reinforcements. It has been verified extensively a gainst data obtained from column tests under concentric and eccentric loads , as well as slow and fast strain rates.