AISC LRFD 1.pdf

GLOSSARYxxixPost-buckling strength. The load that can be carried by an element, member, or frame afterbucklingPrying Action. Lever action that exists in connections in which the line of application ofthe applied load is eccentric to the axis of the bolt, causing deformation of the fittingand an amplification of the axial force in the boltRedistribution of moment. A process which results in the successive formation of plastichinges so that less highly stressed portions of a structure may carry increased momentsRelative Brace. A brace that controls the relative movement of two adjacent brace pointsalong the length of a beam or column or the relative lateral displacement of two storiesin a frame. (See nodal brace)Required strength. Load effect (force, moment, stress, as appropriate) acting on elementor connection determined either by structural analysis from the factored loads (usingappropriate critical load combinations) or explicitly specifiedResidual stress. The stresses that remain in an unloaded member after it has been formedinto a finished product. (Examples of such stresses include, but are not limited to, thoseinduced by cold bending, cooling after rolling, or welding)Resistance. The capacity of a structure or component to resist the effects of loads. It isdetermined by computations using specified material strengths, dimensions and formulasderived from accepted principles of structural mechanics, or by field tests or laboratorytests of scaled models, allowing for modeling effects and differences betweenlaboratory and field conditions. Resistance is a generic term that includes both strengthand serviceability limit statesResistance factor. A factor that accounts for unavoidable deviations of the actual strengthfrom the nominal value and the manner and consequences of failureRigid frame. A structure in which connections maintain the angular relationship betweenbeam and column members under loadRoot of the flange. Location on the web of the corner radius termination point or the toe ofthe flange-to-web weld. Measured as the k distance from the far side of the flangeRotation capacity. The incremental angular rotation that a given shape can accept prior tolocal failure defined as R =( u / p ) where u is the overall rotation attained at the factoredload state and p is the idealized rotation corresponding to elastic theory appliedto the case of M = M pSt. Venant torsion. That portion of the torsion in a member that induces only shear stressesin the memberSecond-order analysis. Analysis based on second-order deformations, in which equilibriumconditions are formulated on the deformed structureService load. Load expected to be supported by the structure under normal usage; oftentaken as the nominal loadServiceability limit state. Limiting condition affecting the ability of a structure to preserveits appearance, maintainability, durability, or the comfort of its occupants or functionof machinery under normal usageLRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION