Maximum deflection of symmetric wall-frame buildings

Abstract

The system of governing differential equations of lateral deflection of symmetric multi-storey buildings subjected to uniformly distributed horizontal load is presented. It is shown that the “standard” equivalent column approach (when the stiffnesses of the bracing units are added up) is only applicable to the deflection analysis in the rare case when the system only consists of shear walls and a single framework. When the bracing system contains more frameworks, then a more sophisticated approach is needed where the full interaction between the vertical elements in bending and shear may need to be taken into account.

Two new methods are developed for the determination of the maximum deflection of mixed bracing systems consisting of frameworks and shear walls: one is very simple while the other one is more accurate. The accuracy of both procedures is demonstrated using the results of over 200 bracing systems. The error range of the more accurate method is -4% to +4% when the buildings contain frameworks and shear walls/cores. A worked example and step-by-step instructions are presented to aid practical application.