Behaviour of ductile hollow reinforced concrete columns

An experimental investigation into the seismic performance of ductile hollow reinforced concrete bridge piers is described. Four 3.2 m high specimens, 750 mm square with 120 mm thick walls containing 60 longitudinal steel bars and different arrangements of confining steel in the plastic hinge zone were subjected to a constant axial load and cyclic lateral displacements. An assessment of the effect of axial load and the amount of transverse steel on the rotational capacity of the plastic hinge is made. The specimens performed satisfactorily at member ductilities between 6 and 8 without any significant degradation of strength under cyclic loading.