Influence of longitudinal steel on ductility of square columns under axial load;

This paper presents calculation methods for reinforced concrete eccentric compression member with ring section, its contents are determination of longitudinal steel for new design member and calculation of carrying capacity for already reinforced members.

The problems concerning adoption of longitudinal bearing force reinforcement in the design of frame structure of the first and second grade earthquake-resistant project are of top importance,that is to say, the longitudinal bearing force reinforcement will play a very important role in the fighting against earthquake forces.