Editing Limit state design (section)

{{Short description|Design method in structural engineering}}
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'''Limit State Design''' ('''LSD'''), also known as ''' Load And Resistance Factor Design''' ('''LRFD'''), refers to a design method used in [[structural engineering]]. A '''limit state''' is a condition of a structure beyond which it no longer fulfills the relevant design criteria.<ref name="EN1990">EN 1990:2002 E, Eurocode - Basis of Structural Design, CEN, November 29, 2001</ref> The condition may refer to a degree of [[Structural load|loading]] or other actions on the structure, while the criteria refer to structural integrity, fitness for use, durability or other design requirements. A structure designed by LSD is proportioned to sustain all actions likely to occur during its design life, and to remain fit for use, with an appropriate level of [[Reliability engineering|reliability]] for each limit state. Building codes based on LSD implicitly define the appropriate levels of reliability by their prescriptions.

The method of limit state design, developed in the USSR and based on research led by Professor N.S. Streletski, was introduced in USSR building regulations in 1955.