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%.本文提出一种基于计算机辅助程序的算法，用于评估隔震钢筋混凝土框架结构采用直接位移法设计时所需的逐层柱截面尺寸。由于隔震建筑的设计目标多为在频谱相容地震动作用下达到低层间位移的完全可运行性能水准，因此需将设计层间位移控制在较低水平。本研究采用铅芯橡胶支座（Lead Rubber Bearing）作为隔震支座，并依据UBC-97最大竖向荷载法进行设计。该算法考虑的框架变形分量包括：弯曲效应引发的柱端位移、剪切效应引发的柱平均位移，以及弯曲与剪切共同引发的节点转角。研究表明，所提方法可针对不同建筑平面、层数不超过9层、基础位移达350mm且目标层间位移不超过0.25%的各类建筑，有效确定其逐层柱截面尺寸。