Simplified column shortening analysis of a multi-storey reinforced concrete frame

An improved column shortening analysis method which can be used at the design stage of a tall building has been proposed. The proposed analysis method considers construction sequences, the restraining effect of horizontal members, as well as creep and shrinkage. The whole analysis period is divided into two phases: before completion and after completion, and correction factors are applied only to the before‐completion phase to consider the gradual nature of construction sequences. Age‐adjusted effective moduli of the horizontal members considering the long‐term behaviour of the members are used for more exact internal forces. Column shortenings of a 70‐storey reinforced concrete frame–shear wall building were investigated as a numerical example. It is shown that the proposed analysis method can be used effectively to evaluate the effects of the differential column shortening to the horizontal members at the design stage. Copyright © 2010 John Wiley & Sons, Ltd.