About of seismic capacity of bridge piers: A simplified approach

This paper extends a previous study proposed by the same authors in order to assess the response of the critical circular pier under combined axial stress and bending. The moment-curvature relationship of the critical section, given initially as a bilinear curve defined by three parameters (elastic stiffness, displacement at yielding, displacement at collapse), is now defined by a curve at three branches built thank to a more refined purely parametric approach. The main points of the curve (corresponding to the yield strength of steel, the maximum compressive stress of the concrete and the same at the ultimate limit state in confined conditions) are uniquely identified taking into account all contributions provided by technical rules in sections concerning to safety assessments of existing buildings. The methodology provides dimensionless formulations which allow obtain the main coordinates of the moment-curvature relationship. The procedure is simple and easy to use in the vulnerability seismic assessment of bridges but also for evaluation of the rotational capacity of generic RC building elements (beams, columns).