Local deformations and rotational degrees of freedom at beam-wall joints

Abstract

Local deformations at beam-wall joints can significantly reduce the effective stiffness of coupling beams in shear/core wall structures. This phenomenon has been studied by many researchers and several methods of allowing for such effects have already been developed. However, in the existing methods, the beam-wall joint rotations are often mistaken as the rotations of the horizontal rigid arms leading to incompatibility between the beam and wall elements. Moreover, many practical difficulties with the actual applications of these methods have been encountered. In this paper, it is proposed that in order to resolve the problem of incompatibility between the beam and wall elements, the definition of the joint rotations should be changed to the rotations of the beam-wall interfaces. A new method of using joint elements to model the joint deformations, which can overcome the problems with the existing methods, is proposed and two alternative beam elements with joint deformations taken into account are developed. Finite element analysis is used to evaluate the local deformations and determine the joint element properties.