Column size for direct displacement based design of base-isolated RC frame buildings

In this paper, a method of computer-added program-based algorithm is introduced to evaluate the possible floor-wise column size for direct displacement-based design of base-isolated reinforced concrete frame buildings. The design storey drifts are kept low as base isolated buildings are mostly intended to achieve low storey drift fully-operational performance level under spectrum-compatible ground motions. Lead rubber bearing is used as base isolator and designed according to the UBC-97 maximum vertical load method. The frame deformation components considered in the algorithm are column tip displacement due to flexure, average column displacement due to shear, and joint rotation due to flexure and shear. It was observed that the proposed method effectively determines the storey-wise column size for various building plans, heights upto 9-storey and base displacement upto 350mm for target storey drift upto 0.25%.