Structural Engineering Definitions PDF

Here is the conversion of the provided text into a organized markdown format. ### Amplification factor A multiplier of the value of moment or deflection in the unbraced length of an axially loaded member to reflect the secondary values generated by the eccentricity of the applied axial load within...

Here is the conversion of the provided text into a organized markdown format. ### Amplification factor A multiplier of the value of moment or deflection in the unbraced length of an axially loaded member to reflect the secondary values generated by the eccentricity of the applied axial load within the member. ### Beam A structural member whose primary function is to carry loads transverse to its longitudinal axis. ### Beam-column A structural member whose primary function is to carry loads both transverse and parallel to its longitudinal axis. ### Bent A plane framework of beam or truss members which support loads and the columns which support these members. ### Biaxial Bending Simultaneous bending of a member about two perpendicular axes. ### Braced Frame A frame in which the resistance to lateral load or frame instability is primarily provided by a diagonal, a K-brace or other auxiliary system of bracing. ### Driftla braatuVA Ahrunt alaounge with little or no prior ductilo doformation ### Buckling Load The load at which a perfectly straight member under compression assumes a deflected position. ### Built-up Member A member made of structural metal elements that are welded, bolted, or riveted together. ### Chevron Bracing A form of bracing where a pair of braces located either above or below a beam terminates at a single point within the clear beam span. ### Cladding The exterior covering or the structural components of a building. ### Cold-formed Members Structural members formed from steel without the application of heat. ### Column A structural member whose primary function is to carry loads parallel to its longitudinal axis. ### Column Curve A curve expressing the relationship between axial column strength and slenderness ratio. ### Combined Mechanism A mechanism determined by plastic analysis procedure which combines elementary beam, panel, and joint mechanisms. ### Compact Section Compact sections are capable of developing a fully plastic stress distribution and possess a rotation capacity of approximately 3 before the onset of local buckling. ### Composite Beam A steel beam structurally connected to a concrete slab so that the beam and slab respond to loads as a unit. See also concrete-encased beam. ### Composite Column A steel column fabricated from rolled or built-up steel shapes and encased in structural concrete or fabricated from steel pipe or tubing and filled with structural concrete. ### Concrete-encased Beam A beam totally encased in concrete cast integrally with the slab. ### Connection Combination of joints used to transmit forces between two or more members; a group of elements that connect the members to the joint. Categorized by the type and amount of force transferred (moment, shear, end reaction). ### Critical Load The load at which bifurcation occurs as determined by a theoretical stability analysis. ### Curvature The rotation per unit length due to bending. ### Design Strength Resistance (**force, moment, stress,** *as appropriate*) provided by an element or connection; the product of the nominal strength and the resistance factor. ### Diagonal Bracing Inclined structural members carrying primarily axial load employed to enable a structural frame to act as a truss to resist horizontal loads. A form of bracing that diagonally connects joints at different levels. ### Diaphragm Floor slab, metal wall, or roof panel possessing a large in-plane shear stiffness and strength adequate to transmit horizontal forces to resisting elements. ### Diaphragm Action The in-plane action of a floor system (*also roofs and walls*) such that all columns entering into the floor from above and below are maintained in the same position relative to each other. ### Double Curvature A bending condition in which end moments on a member cause the member to assume an S-shape. ### Drift Lateral deflection of a building. ### Drift Index The ratio of lateral deflection to the height of the building. ### Ductility Factor The ratio of the total deformation at maximum load to the elastic-limit deformation. ### Eccentric Braced Frame (EBF) A diagonal-braced frame in which at least one end of each bracing member connects to a beam a short distance from a beam-to-column connection or from another beam-to-brace connection. ### Effective Length The equivalent length KL used in compression formulas and determined by a bifurcation analysis. ### Effective Length Factor K The ratio between the effective length and the unbraced length of the member measured between the centers of gravity of the bracing members. ## DEFINITION OF TERMS ### Effective Moment of Inertia The moment of inertia of the cross-section of a member that remains elastic when partial plasticization of the cross-section take place, usually under the combination of residual stress and applied stress. Also, the moment of inertia based on effective widths of elements that buckle locally. Also, the moment of inertia used in the design of partially composite members. ### Effective Stiffness The stiffness of a member computed using the effective moment of inertia of its cross-section. ### Effective Width The reduced width of a plate or slab which, with an assumed uniform stress distribution, produces the same effect on the behavior of a structural member as the actual plate width with its non-uniform stress distribution. ### Elastic Analysis Determination of load effects (**force, moment, stress,** *as appropriate*) on members and connections based on the assumption that material deformation disappears on removal of the force that produced it. ## DEFINITION OF TERMS ### Elastic-perfectly Plastic A material which has an idealized stress-strain curve that varies linearly from the point of zero strain and zero stress up to the yield stress of the material, and then increases in strain at the value of the yield stress without any further increases in stress. ### Embedment A steel component cast in a concrete structure which is used to transmit externally applied loads into the concrete structure by means of bearing, shear, bond, friction, or any combination thereof. The embedment may be fabricated from structural-steel plates, shapes, bars, bolts, pipe studs, reinforcing steel, reinforcing bars, sheet connectors, or any combination thereof. ### Encased Steel Structure A steel-framed structure in which some of the individual frame members are encased in concrete and cast-in-place concrete. ### Euler Formula The mathematical relationship expressing the value of the Euler load in terms of the modulus of elasticity, the moment of inertia of the cross-section, and the length of a column. ## DEFINITION OF TERMS ### Euler Load The critical load of a perfectly straight, centrally loaded, pin-ended column. ### Eyebar A particular type of pin-connected tension member of uniform thickness with a forged or same cut head of greater width than the body proportioned to provide approximately equal strength in the head and body. ### Factored Load The product of the nominal load and a load factor. ### Fastener Generic term for welds, bolts, rivets, or other connecting means. ### Fatigue A fracture phenomenon resulting from a fluctuating stress cycle. ### First-order Analysis Analysis based on first-order deformations, in which equilibrium conditions are formulated on the undeformed structure. ### Flame-cut Plate A plate in which the longitudinal edges have been prepared by oxygen cutting from a large plate. ### Flat Width For a rectangular tube, the nominal width minus twice the outside corner radius. In the absence of knowledge of the corner radius, the flat width may be taken as the total section width minus three times the thickness. ### Flexible Connection A connection permitting a portion, but not all, of the simple beam rotation of a member end. ### Floor System The system of structural components separating the stories of a building. ### Force Resultant of distribution of stress over a prescribed area. A reaction that develops in a member as a result of load (**formerly called total stress or stress**). Generic term signifying axial loads, bending moment, torques, and shears. ### Hybrid Beam A fabricated steel beam composed of flanges with a greater yield strength than that of the web. Whenever the maximum flange stress is less than or equal to the web yield stress, the girder is considered homogeneous. ### Inelastic Action Material deformation that does not disappear on removal of the force that produced it. ### Instability A condition reached in the loading of an element or structure in which continued deformation results in a decrease of load-resisting capacity. ### Joint Area where two or more ends, surfaces, or edges are attached. The entire assemblage at the intersection of two members. Categorized by type weld used and method of force transfer. ### K-bracing A system of struts used in a braced frame in which the pattern of struts resembles the letter K, either normal or on its side. That form of bracing where a pair of braces locate at one end of a column terminates at a single point within the clear column height. ### Lateral Bracing Member A member utilized individually or as a component of a lateral bracing system to prevent buckling of members or elements and/or to resist lateral loads. ### Lateral (or Lateral-torsional) Buckling Buckling of a member involving lateral deflection and twist. ### Limit State A condition in which a structure or component becomes unfit for service and is judged either to be no longer useful for its intended function (serviceability limit state) or to be unsafe (strength limit state). ### Limit States Limits of structural usefulness, such as brittle fracture, plastic collapse, excessive deformation, durability, fatigue, instability, and serviceability. ### Link Beam The part of a beam in an eccentrically brace frame which is designed to yield shear and/or bending so that buckling of the bracing members is prevented. ### Load Factor A factor that accounts for unavoidable deviations of the actual load from the nominal value and for uncertainties in the analysis that transform the load into a load effect. ### Loads Forces or other actions that arise on structural systems from the weight of all permanent construction, occupants and their possessions, environmental effects, foundation settlement, and indirect structural system changes. Permanent loads are those loads in which variations in time are rare or of small magnitude. All other loads are variable loads. ### LRFD (Load and Resistance Factor Design) A method of proportioning structural components (*members, connectors, connecting elements, and assemblages*) such that no applicable limit state is exceeded when the structure is subjected to all appropriate load combinations. ### Local Buckling The buckling of a compression element which may precipitate the failure of the whole member. ### Nominal Loads The magnitudes of the loads specified by the applicable code. ### Nominal Strength The capacity of a structure or component to resist the specified loads, as determined by computations using specified material strengths and dimensions and formulas derived from accepted principles of structural mechanics or by field tests or laboratory tests of scaled models, allowing for modeling effects and differences between laboratory and field conditions. ### Noncompact Section Noncompact sections can develop full plastic stress in compression elements before local buckling occurs, but will not resist inelastic local buckling at strain levels required for a fully plastic stress distribution. ### P-Delta Effect Secondary effect of column axial loads and lateral deflection on the moments in members. ### Panel Zone The zone in a beam-to-column connection that transmits moments by a shear panel ### Partially Composite Beam A composite beam for which the shear strength of shear connectors governs the flexural strength. ### Plane Frame A structural system assumed for the purpose of analysis and design to be two-dimensional. ### Plate Girder A built-up structural beam. ### Post-buckling Strength The load that can be carried by an element, member, or frame after buckling. ### Redistribution of Moment A process that results in the successive formation of plastic hinges so that less highly stressed portions of a structure may carry increased moments. ### Required Strength Load effect (*force, moment, stress, as appropriate*) acting on an element or connection determined by structural analysis from the factored loads (using most appropriate critical load combinations). ### Residual Stress The stress that remains in an unloaded member after it has been formed into a finished product. (Examples of such stresses include, but are not limited to, those induced by cold bending, cooling after rolling, or welding.) ### Resistance Factor A factor that accounts for unavoidable deviations of the actual strength from the nominal value and the manner and consequences of failure. ### Rigid Frame A structural frame in which connections make the angular relationship between beam and column members under load. ### Root of the Flange Location on the inside of the corner radius termination point or end of the flange-to-web weld. Measured as the k-distance from the tip of the flange. ### Second-order Analysis Analysis based on second-order deformations, in which equilibrium conditions are formulated on the deformed structure. ### Service Load Load expected to be supported by the structure under normal usage, often taken as the nominal load. ### Serviceability Limit State Limiting condition affecting the ability of a structure to preserve its appearance, maintainability, durability, or the comfort of occupants or function of machinery under normal usage. ### Shape Factor The ratio of the plastic moment to the yield moment, or the ratio of the plastic modulus to the section modulus for a cross-section. ### Shear-friction Friction between the embedment and the concrete that transmits shear loads. The relative displacement in the plane of the shear load is considered to k resisted by shear-friction anchors located perpendicular to the plane of the shear loac ### Shear Lugs Plates, welded studs, bolts, and other steel shapes that are embedded in the concrete and located transverse to the direction of the shear force and that transmit shear loads introduced into the concrete by local bearing at the shear lug-concrete interface. ### Shear Wall A wall that in its own plane resists shear forces resulting from applied wind, earthquake, or other transverse loads or provides frame stability. Also called a structural wa ### Sidesway The lateral movement of a structure under the action of lateral loads, unsymmetrical vertical loads, or unsymmetrical properties of the structure. ### Sidesway Buckling The buckling mode of a multistory frame precipitated by the relative lateral displacements of joints, leading to failure by sidesway of the frame. ### Single Curvature A deformed shape of a member having one smooth continuous arc, as opposed to double curvature which contains a reversal. ### Slender Section The cross-section of a member which will experience loca buckling in the elastic range. ### Slenderness Ratio The ratio of the effective length of a column to the radius of gyration of the column, both with respect to the same axis of bending. ### Slip-critical Joint A bolt joint in which the slip resistance of the connection is required. ### Space Frame A three-dimensional structural framework (as contrasted to a plane frame). ### Splice The connection between two structural elements aligned at their ends to form a single, longer member. ### Stability-limit Load Maximum (theoretical) load a structure can support when second-order instability effects are included. ### Stepped Column A column with changes from one cross-section to another occurring at abrupt points within the length of the column. ### Stiffener A member, usually an angle or plate, attached to a plate or web of a beam or girder to distribute load, to transfer shear, or to prevent buckling of the member to which it is attached. ### Stiffness The resistance to deformation of a member or structure measured by the ratio of the applied force to the corresponding displacement. ### Story Drift The difference is horizontal deflection at the top and bottom of a story. ### Strain Hardening Phenomenon wherein ductile steel, after undergoing considerable deformation at or just above yield point, exhibits the capacity to resist substantially higher loading than that which caused initial yielding. ### Strain-hardening Strain For structural steels that have a flat (plastic) region in the stress-strain relationship, the value of the strain at the onset of strain hardening. ### Strength Design A method of proportioning structural members using load factors and resistance factors such that no applicable limit state is exceeded (also called load and resistance factor design). ### Stress Force per unit area. ### Stress Concentration Localized stress considerably higher than average (even in uniformly loaded cross-sections of uniform thickness) due to abrupt changes in geometry or localized loading.\ ### Strong Axis The major principal axis of a cross-section. ### Structural System An assemblage of load-carrying components which are joined together to provide regular interaction or interdependence. ### Stub Column A short compression-test specimen, long enough for use in measuring the stress-strain relationship for one complete cross-section, but short enough to avoid buckling as a column in the elastic and plastic ranges. ### Supported Frame A frame which depends upon adjacent braced or unbraced frames for resistance to lateral load or frame instability. (This transfer of load is frequently accomplished by the floor or roof system through diaphragm action or by horizontal cross-bracing in the roof or floors.) ### Tangent Modulus At any given stress level, the slope of the stress-strain curve of the material in the inelastic range as determined by the secant to the curve at a small specimen under uniaxial loading. ### Temporary Structure A general term for anything that is built or constructed (usually to carry construction loads) that will eventually be removed before or after completion of construction and does not become part of the permanent structural system. ### Tensile Strength The maximum tensile stress that a material is capable of sustaining. ### Tension Field Action The behavior of a plate girder panel under shear force in which diagonal tensile stresses develop in the web, and compressive forces develop in the transverse stiffeners in a manner analogous to a Pratt truss. ### Toe of the Fillet Termination point of fillet weld or rolled section fillet. ### Torque-tension Relationship Term applied to the wrench torque required to produce specified pre-tension in high-strength bolts. ### Turn-of-nut Method Procedure whereby the specified pretension in high-strength bolts is controlled by rotation of the wrench a predetermined amount after the nut has been tightened to a snug fit. ### Unbraced Frame A frame in which the resistance to lateral load is provided by the bending resistance of frame members and their connections. ### Unbraced Length The distance between braced points of a member, measured between the centers of gravity of the bracing members. ### Undercut A notch resulting from the melting and removal of base metal at the edge of a weld. ### Upper Bound Load A load computed on the basis of an assumed mechanism which will always be at least equal to or greater than the true ultimate load. ### V-bracing That form of chevron bracing that intersects a beam from above Inverted V-bracing is that form of chevron bracing that intersects a beam from below. ### Vertical Bracing System A system of shear walls, braced frames, or both, extending throughout one or more floors of a building. ### Warping Torsion That portion of the total resistance to torsion that is provided by resistance to warping of the cross-section. ### Weak Axis The minor principal axis of a cross-section. ### Weathering Steel A type of high-strength, low-alloy steel which can be used in normal environments (not under water) and outdoor exposures without protective paint covering. This steel develops tight adherent rust at a decreasing rate with respect to time. ### Web Buckling The buckling of a web plate. ### Web Crippling The local failure of a web plate in the immediate vicinity of a concentrated load or reaction. ### Working Load Also called service load, the actual load assumed to be acting on the structure. ### X-bracing That form of bracing where a pair of diagonal braces cross near mid-length of the bracing members. ### Yield Moment In a member subjected to bending, the moment at which an outer fiber first attains the yield stress. ### Yield Plateau The portion of the stress-strain curve for uniaxial tension or compression in which the stress remains essentially constant during a period of substantially increased strain. ### Yield Point The first stress in a material at which an increase in strain occurs without an increase in stress, the yield point is less than the maximum attainable stress. ### Yield Strength The stress at which a material exhibits a specified limiting deviation from the proportionality of stress to strain. Deviation expressed in terms of strain. ### Yield Stress Yield point, yield strength, or yield-stress level as defined. ### Yield-stress Level The average stress during yielding in the plastic range, the stress determined in a tension test when the strain reaches 0.005 mm per mm.