| Abstract: | This paper presents an efficient, computer‐based technique for the optimum drift design of tall reinforced concrete (RC) buildings including non‐linear cracking effects under service loads. The optimization process consists of two complementary parts: an iterative procedure for the non‐linear analysis of tall RC buildings and a numerical optimality criteria (OC) algorithm. The non‐linear response of tall RC buildings due to the effects of concrete cracking is obtained by a series of linear analyses, the so‐called direct effective stiffness method. In each linear analysis, cracked structural members are first identified and their stiffness modified based on a probability‐based effective stiffness relationship. Stiffness reduction coefficients are introduced as measures of the remaining stiffness for structural elements after cracking. A rigorously derived OC method is developed to solve for the minimum weight/cost design problem subject to multiple drift constraints and member sizing requirements. A shear wall‐frame example is presented to illustrate the application of this optimal design method. The design results of the optimized structure with cracking effects are compared to those of the linear‐elastic structure without concrete cracking. Copyright © 2005 John Wiley & Sons, Ltd. |
