scope:

It is well known that a building frame, unrestrained against side sway at the floor levels, may buckle as a unit in the lateral direction when the applied load has reached a certain critical value. This phenomenon is often referred to as "frame instability." A great deal of research work has been done on this problem in the past, and numerous methods are now available for obtaining exact and/or approximate solutions. This paper contains a general survey of the various frame instability theories, discussions of several recent papers, and a review of current and future research trends. A list of references and summaries of solutions for some practical frames are also included.