Drift

Definition

Lateral deflection of a building caused by wind or earthquake loads; the horizontal displacement or movement of a structure when subjected to lateral forces.

Purpose

Drift is a critical factor in structural engineering, as excessive drift can lead to structural damage or failure. Understanding and controlling drift ensures the stability and safety of buildings during windstorms, earthquakes, and other lateral force events.

Examples of Use

1. High-Rise Buildings: Engineers calculate and design for drift to ensure stability during high winds.
2. Bridges: Drift calculations are essential for the design of long-span bridges to withstand lateral forces.
3. Seismic Design: Structures in earthquake-prone areas are designed to limit drift and prevent collapse.

Related Terms

• Shear Wall: A wall designed to resist lateral forces and control drift.
• Moment Frame: A structural system with beams and columns designed to resist bending and lateral forces.
• Base Isolation: A technique used to reduce seismic forces transmitted to a structure.

Notes

• Building codes specify maximum allowable drift to ensure safety.
• Advanced modeling and simulation software are used to predict and analyze drift in structures.