definition
strict definition
rigid frame
A framing system whose moment-resisting joints help the framework resist distortion.
A rigid frame is a simple framework which uses strong joints to resist distortion.
The joints resist relative rotation between connected members and transmit bending moments. The members and their connections therefore work together to resist distortion; strong members joined by freely rotating connections do not provide the same frame action.
A trussed frame uses diagonal braces, while a shear wall resists forces in the plane of a wall. Frame action can also work together with a wall in a shear wall plus frame system. The rigid-frame principle does not impose a fixed story limit.