Addressing Differential Axial Deformation Effect and Sway in 3D Building Frame Analysis

Abstract

The Differential Axial Deformation Effect (DADE) is a significant consideration in the 3D analysis of building frames, where elements like columns and walls experience compression forces leading to differential shortening. Traditional design methods often overlook DADE, yet the existing building stock seems serviceable despite this omission. However, modern 3D analysis inherently introduces DADE, prompting designers to seek methods to approximate traditional design forces while utilizing advanced analysis techniques. The aim is to achieve design forces close to those historically used, ensuring structural integrity without disregarding DADE entirely. The methods outlined in this report demonstrate how to reconcile 3D analysis results with traditional design principles while also addressing concerns about sway deflections and the need for a conservative approach. While there's a debate about the economic viability of designing for a wider envelope of design conditions, the report illustrates that the additional reinforcement needed is typically minimal. Notably, the DADE phenomenon is universal across Finite Element Method (FEM) analysis software, and the strategies discussed here can be applied across different platforms. The notion that staged construction analysis effortlessly resolves DADE issues is debunked. Staged construction analysis is complex, doesn't fully eliminate DADE, and can yield unreliable results if not used carefully. In summary, this report offers practical insights into navigating DADE in 3D structural analysis, emphasizing the importance of balancing modern techniques with traditional design considerations