Analysis of buildings using strain-based element with rotational DOFs

Abstract

The existing problems with the finite element analysis of tall buildings are reviewed. It is found that: (1) many different definitions have been used for the nodal rotations, but only defining them as rotations of vertical fibers is really appropriate; (2) most simple elements are afflicted by the presence of parasitic shear, while strain function formulation provides a good means of solving the problem; and (3) the incorporation of some commonly accepted assumptions can substantially improve the computational efficiency of the method. Based on these observations, a new strain-based plane stress-element with rotational degrees of freedom defined as vertical fiber rotations is developed. The element is free of parasitic shear and converges so quickly that it can be used at a rate of only one layer per story. If implemented in conjunction with the assumption that the distortion of the sectional shape of the wall system is negligible, the proposed method is computationally as efficient as the frame method.