Frame sway refers to the lateral movement or oscillation of a structural frame, typically a building frame, in response to external forces like wind or seismic activity. Unlike a rigid, non-sway frame braced against lateral movement, a sway frame is designed to allow for a degree of flexibility. This flexibility helps the structure absorb and dissipate these forces, reducing the risk of structural damage.
Types of Frames and Sway
There are two main types of frames regarding sway:
-
Sway Frames (Flexible Frames, Moment-Resisting Frames): These frames are designed to withstand lateral loads by flexing. They utilize moment connections between beams and columns to transfer loads. They are commonly used in high seismic and wind areas where flexibility is crucial for absorbing energy from lateral forces. [Reference: In summary, sway frames are designed to allow for movement and are used in high seismic and wind areas. They are also known as Moment-resisting frames, they use moment connections to transfer the load between the beams and columns. They are also known as Flexible frames, as they allow flexibility to the structure.]
-
Non-Sway Frames (Braced Frames): These frames are sufficiently braced by lateral bracing elements (like shear walls) to prevent significant lateral movement. They resist lateral loads primarily through shear. [Reference: A frame is considered to be non-sway (braced) if it is sufficiently braced by lateral bracing elements like structural walls.]
Examples of Frame Sway in Different Contexts
The term "frame sway" can be applied in various contexts, not just building structures:
- Automotive: In vehicles, the sway bar (also called anti-roll bar) helps to reduce body roll during cornering by connecting opposite wheels. Problems with the sway bar mounts, like rust or breakage, could affect the vehicle's frame. [References: sway bar bolt rubbing on frame, Pics of mystery frame part - snapped sway bar mount? , Frame broke at front sway bar mount]
- Industrial Equipment: Some industrial equipment, like certain types of aerial work platforms (AWPs), might use a "frame sway" function for controlled movement. However, malfunctions of this function can result in unintended movement. [Reference: Genie GTH1056. The frame sway function isn't working.]
- Rollerblading: In the context of rollerblades, "sway" refers to the ability of a frame and wheel setup to smoothly handle varied terrain. Different frame and wheel types influence the degree of maneuverability and stability. [Reference: What Frames/Wheels Can I/Should I Put on My USD Sway Team IIs]
Practical Insights and Solutions
Designing and constructing buildings to account for sway is critical in ensuring structural integrity and safety. Structural engineers carefully analyze anticipated loads and design frames accordingly. This includes selecting appropriate materials, connection types, and bracing systems.
