Natural Frequency Evaluation of Coupled Shear Walls

Based on the concept of lumped masses and the established equivalent continuous approach for the analysis of coupled shear walls, a continuous-discrete approach for evaluating their natural frequencies is proposed in this paper. The coupled shear wall system is treated as a continuous system (i.e. where the discrete beams are replaced by an equivalent continuous medium) and a discrete system (or lumped mass system) at different stages of dynamic analysis. The advantages of the two types of analytical system are jointly utilised. The accuracy and eficiency of the methodology adopted in the continuous-discrete approach are verified by making comparisons with the precise classical approach and a couple of approximate approaches for evaluating the natural frequencies of typical coupled wall structures. The minimum number of lumped masses needed in the present approach to obtain an acceptably accurate value of natural frequency for any modal vibration of coupled shear walls is also discussed. In addition, a simple chart, based on the continuous and the continuous-discrete approaches, for estimating the fundamental frequencies of coupled shear walls is presented. A numerical example is given to show the application of the chart and the accuracy of the procedure in estimating the fundamental frequencies of coupled shear walls.

Guo-Qiang Li and B.S. Choo