Deformation limit states for circular reinforced concrete bridge columns

Through the use of moment-curvature analysis of circular bridge columns, di mensionless serviceability and damage control curvature relationships are d eveloped that depend only on the column axial load ratio and section diamet er. These relationships are used to establish curvature, displacement ducti lity, drift ratio, and equivalent viscous damping capacities for the design limit states considered. It is shown that current code-based design approa ches, which imply a constant ductility factor, will generally result in dam age levels that are highly variable. The paper also discusses implications of the study on limit-states design approaches such as displacement-based d esign.