Rotational DOF in the frame method analysis of coupled shear/core wall structures

Abstract

This study shows that the common practice in existing frame methods of assuming the rotations of the coupling beams at beam-wall joints to be equal to the rotations of the horizontal rigid arms would lead to incompatibility between the beam and wall elements at their joints and eventually errors in the effective stiffness of the coupling beams. It is postulated that to resolve the problem, the rotational DOF at the beam-wall joints should be changed to the rotations of the vertical fibres there. This would, however, necessitate the use of frame elements with two rotational DOF at each end or solid wall elements with rotational DOF at each node to model the structure. Such required frame and solid wall elements are developed in this paper based on a Timoshenko beam element with two rotational DOF at each end. The resulting new frame method is much more accurate and versatile than the existing frame methods.