Moment-resisting frame is a rectilinear assemblage of beams and columns, with the beams rigidly connected to the columns. Resistance to lateral forces is provided primarily by

rigid frame Rigid or rigidity may refer to: Mathematics and physics *Stiffness, the property of a solid body to resist deformation, which is sometimes referred to as rigidity *Structural rigidity, a mathematical theory of the stiffness of ensembles of rig ...

action – that is, by the development of

bending moment In solid mechanics, a bending moment is the Reaction (physics), reaction induced in a structural element when an external force or Moment of force, moment is applied to the element, causing the element to bending, bend. The most common or simplest ...

and

shear force In solid mechanics, shearing forces are unaligned forces acting on one part of a Rigid body, body in a specific direction, and another part of the body in the opposite direction. When the forces are Collinearity, collinear (aligned with each ot ...

in the frame members and joints. By virtue of the rigid beam–column connections, a moment frame cannot displace laterally without bending the beams or columns depending on the geometry of the connection. The bending rigidity and strength of the frame members is therefore the primary source of lateral stiffness and strength for the entire frame. The

1994 Northridge earthquake The 1994 Northridge earthquake affected Greater Los Angeles, California, on January 17, 1994, at 04:30:55 PST. The epicenter of the moment 6.7 () blind thrust earthquake was beneath the San Fernando Valley. Lasting approximately 8 seconds ...

revealed a common flaw in steel-frame construction — poorly welded moment connections — and building codes were revised to strengthen them.

Early history

Steel moment-resisting frames have been in use for more than one hundred years, dating to the earliest use of structural steel in building construction. Steel building construction with the frame carrying the vertical loads initiated with the

Home Insurance Building The Home Insurance Building was a skyscraper that stood in Chicago from 1885 to its demolition in 1931. Originally ten stories and tall, it was designed by William Le Baron Jenney in 1884 and completed the next year. Two floors were added in ...

in Chicago, a 10-story structure constructed in 1884 with a height of 138 ft, often credited with being the first skyscraper. This and other tall buildings in Chicago spawned an entire generation of tall buildings, constructed with load bearing steel frames supporting concrete floors and non-load bearing, unreinforced masonry

infill wall In urban planning, infill, or in-fill, is the rededication of land in an urban environment, usually open-space, to new construction. Infill also applies, within an urban polity, to construction on any undeveloped land that is not on the urban m ...

s at their perimeters. Framing in these early structures typically utilized "H" shapes built up from plates, and "L" and "Z" sections.Hamburger, Ron. et al., (2009). ''Seismic Design of Steel Structures''. National Institute of Standards and Technology . NIST GCR 09-917-3.page 3

References

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