Structural Terms Flashcards
Force System: all having the same direction
Parallel
Force System: all acting in a single plane of a vertical wall
Coplanar
Force system: all having their lines of action intersect at a common point.
Concurrent
Force system: force x distance, moment can be about any point called CENTER OF MOMENT
Moment
Force system: distance from center of moment to force, shortest of perpendicular distance from the center or moment to line of action of force
Moment Arm
Properties of forces: the amount of force, N
Magnitude
Properties of forces: refers to the orientation of its path or line of action. It is usually describes by the angle that line of of action make with some references.
Direction
Properties of forces: refers to the manner in which it acts along its line of action
Sense
Kinds of load: example is a beam supporting a column
Concentrated Loads
Kinds of loads: a series of uniform concentrated loads, but for 5 or more uniformly spaces concentrated loads.
Uniform Loads
Kind of loads: Varying load, moment load
Other loads
Types of Support
Hinged, Roller & Fixed/Restrained
Types of Beams
Simply supported, Simply supported with over hang - cantilever beam, propped cantilever beam, continuous beam
Type of force that pulls away from joint
Tension
Type of force that pushes toward joint
Compression
Type of force for connections
Shear
ASTM
American Society for Testing and Materials
ACI
America Concrete Institute
According to ACI code, If the strain in concrete reaches ____mm, it begins to crack.
.003
AISC
American Institute for Steel Construction
According to AISC, if a grade 60 steel reaches a strain ._____ it begins to yield of.
.0021
Maximum stress which the material springs back to the original length when the load is released.
Proportional Limit
Maximum stress below which the material does not return to its original length but has incurred a permanent deformation we call PERMANENT SET.
Elastic Limit
The stress wherein the deformation increases without any increase in the load. the material at some portion shows a decrease in the cross section.
Yield Point
The maximum stress that can be attained immediately before actual failure or rupture.
Ultimate Strength
Stress at which the material specimen breaks
Rupture Strength
the maximum unit stress permitted for a material in the design of a structural member, usually a fraction of the material’s elastic limit, yield strength, or ultimate strength. Also called ALLOWABLE UNIT STRESS, WORKING STRESS.
Allowable Stress
The range of unit stresses for which a material exhibits elastic deformation.
Elastic range
A temporary change in the dimensions or shape of a body produced by a stress less than the elastic limit of the material.
Elastic deformation
Th property of material that cause it to rupture suddenly under stress with little evident deformation. Since brittle materials lack the plastic behavior of ductile materials, they can give no warning of impending material.
Brittleness
The property of a material that enables it to undergo plastic deformation after being stressed beyond the elastic limit and before rupturing.
Ductility
The property of a material that enables it to deform in response to an applied force and to recover its original size and shape upon removal of the force.
Elasticity
The ability of material to regain and rebound to original shape when the load is released.
Malleability
The property of a material that enables it to absorb energy before rupturing, represented by the area under the stress-strain curve derived from a tensile test of the material.
Toughness
A coefficient of elasticity of a material expressing the ratio between unit stress and the corresponding unit strain caused by the stress, as derived from Hooke’s law and represented by the slope of the straight line portion of the stress-strain line diagram. Also called COEFFICIENT OF ELASTICITY, ELASTIC MODULUS
Modulus of Elasticity
The inelastic strain remaining in a material after complete release of the stress producing deformation.
Permanent set
The stress necessary to produced a specific limiting permanent set in a material. Usually .2% of its original length when tested on tension. also called POOR STRESS
Yield Strength
The behavior an increased rate of load application can cause in normally ductile material
Strain-Rate effect
The brittle behavior low temperatures can causes in a normally ductile material.
Temperature Effect
the time-dependent decrease in stress in a constrained material under a constant load.
Stress Relaxation
The gradual permanent deformation of a body produced by a continued application of stress or prolonged exposure to heat. Creep deflection in a concrete structure continues over time and can be significantly greater than the initial elastic deflection
Creep
The weakening or failure of a material at a stress below the elastic limit when subjected to repeated series of stresses.
Fatigue
Structural properties of A36 steel: Maximum allowable stress (Fv) in shear is
14.5 ksi
Structural properties of A36 steel: Maximum allowable stress (Fb) for bending is
24 ksi
Structural properties of A36 steel: Modulus of elasticity (E) is
29,000 ksi
Weight of water
1000kg/m3
Weight of steel
7850kg/m3
Weight of concrete
2400kg/m3
formula for weight
density x volume
The act of stretching or state of being pulled apart, resulting in the elongation of an elastic body.
Tension
An applied force producing or tending to produce tension in an elastic body.
Tensile Force
A tensile or compressive force acting along the longitudinal axis of a structural member and at the centroid of the cross section, producing axial stress without bending, torsion or shear also called. AXIAL LOAD
Axial Force
The tensile or compressive stress that develops to resist axial force, assumed to be normal to and uniformly distributed over the area of the cross section. Also called DIRECT STRESS, NORMAL STRESS
Axial Stress
The act of shortening or state of being pushed together, resulting in the reduction in size or volume of an elastic body.
Compression
An applied force producing or tending to produce compression in an elastic body.
Compressive Force
Force applied parallel to the longitudinal axis of a structural member but not to the centroid of the cross section, producing bending and uneven distribution of stresses in the section. Also called ECCENTRIC LOAD
Eccentric Force
The internal resistance or reaction of an elastic body to external forces applied to it. Equal to the ratio of force to area and expressed in units of force per unit of cross-sectional area. Also called UNIT STRESS
STRESS
The axial stress that develops at the cross section of an elastic body to resist the collinear tensile force tending to elongate it.
Tensile Stress
The elongation of a unit length of material produces by a tensile stress
Tensile Strain
A measure of ductility of a material, expressed as the percentage increase in length of a steel specimen after failure in tensile test.
Elongation
A measure of ductility of a material, expressed as the percentage decrease in cross-sectional area of a test specimen after rupturing in a tensile test.
Reduction of Area
The resistance of a material to longitudinal stress, measured by the minimum amount of longitudinal stress required to rupture the material.
Tensile Strength
The deformation of a body under the action of an applied force. Strain is a dimensionless quantity, equal to the ratio of the change in size and shape to the original size and shape f a stressed element.
Strain
An instrument for measuring minute deformation in a test specimen caused by tension, compression, bending or twisting. Also called EXTENSOMETER
Strain Gauge
A coefficient of elasticity of material expressing the ratio of longitudinal stress to the corresponding longitudinal strain caused by the strain.
Young’s Modulus (Modulus of Elasticity)
The ratio of lateral strain to the corresponding longitudinal strain in an elastic body under longitudinal stress.
Poisson’s Ratio
The axial stress that develops at the cross section of an elastic body to resist the collinear compressive forces tending to shorten it.
Compressive Stress
The shortening of a unit length of material produced by a compressive stress.
Compressive Strain
The lateral deformation produced in a body by an external force that causes one part of the body to slide relative to an adjacent part in a direction parallel to their plane contact.
Shear
An applied force producing or tending to produce shear in the body.
Shear Force
An internal force tangential to the surface on which it acts, developed by a body in response to shear, shearing in a vertical plane necessarily involves shearing in a horizontal plane and vice versa.
Shearing Force
The force per unit area developed along a section of an elastic body to resist a shear force. Also called SHEAR STRESS, TANGENTIAL STRESS
Shearing Stress
The lateral deformation developed in a body in response to shearing stresses, defined as the tangent of the skew angle of the deformation.
Shearing Strain
A coefficient elasticity of a material, expressing the ratio between shearing stress and the corresponding shearing strain produced by the strain. Also called MODULUS OF RIGIDITY, MODULUS OF TORSION
Shear Modulus of Elasticity
The bowing of an elastic body as an external force is applied transversely to its length.
Bending
A force applied perpendicular to the length of a structural member, producing bending and shear.
Transverse Force
The moment of a force system that causes or tends to cause rotation or torsion.
Torque
The twisting of an elastic body about its longitudinal axis caused by two equal and opposite torques, producing shearing stresses in the body.
Torsion
The depth of concrete section measured from the compression face to the centroid of the tension reinforcement.
Effective Length
The amount of concrete required to protect steel reinforcement from fir and corrosion, measured from the surface of the reinforcement to outer surface of the concrete section.
Cover
The adhesive for per unit area of contact between reinforcing bar and the surrounding concrete developed at any section of a flexural member.
Bond Stress
A bend or curve given to develop an equivalent embedment length, used where there is insufficient room to develop in adequate embedment length.
Hook
A 90 degree, 135 degree, 180 degree bend made at the end of a reinforcing bar according to standards.
Standard Hook
Any of various means, as embedment length or hooked bars, for developing tension or compression in a reinforcing bar on each side of critical section in order to prevent bond failure or splitting.
Anchorage
The section of a flexural concrete member at a point of maximum stress, a point of inflection, or appoint within the span where tension bars are no longer needed to resist stress.
Critical Section
A concrete in which the tension reinforcement theoretically reaches its specified yield strength as the concrete in compression reaches its assumed ultimate strain.
Balanced Section
A concrete. section in which the concrete in compression reaches its assumed ultimate strain before the tension reinforcement reaches its specified yield strength. This is a dangerous condition since failure of the section could occur instantaneously without warning.
Over Reinforced Section
A concrete section in which the tension reinforcement reaches its specified yield strength before the concrete in compression reaches its assumed ultimate strain. This is desirable condition since failure of the section would preceded by large deformations giving prior warning of impending collapse.
Under Reinforced Section
A rigid structural member designed to carry and transfer transverse loads across spaces supporting elements.
Beam
The extent of space between two supports of a structure.
Span
The distance between inner faces of the support of a span.
Clear Span
The center to center distance between the supports of a span.
Effective Span
An external moment tending to cause part of a structure to rotate or bend, equal to the algebraic sum of the moments about the neutral axis of the section under consideration.
Bending Moment
An internal moment equal and opposite to a bending moment, generated by a force couple to maintain equilibrium of the section being considered.
Resisting Moment
The perpendicular distance spanning member deviates from a true course under transverse loading, increasing with load and span, and decreasing with an increase in the moment of inertia of the section of the modulus of elasticity of the material.
Deflection
An imaginary line passing through the centroid of the cross section of a beam, other member subject to bending , along which no bending stresses occur.
Neutral Axis
A combination of compressive and tensile stresses developed at a cross section of structural member to resist transverse force, having a maximum value at the surface furthest from the neutral axis.
Bending Stress
A slight convex curvature intentionally built into beam, girder, or truss to compensate for an anticipated deflection.
Camber
An external shear force at a cross section of a beam or other member subject to bending, equal to the algebraic sum of transverse forces on one side of the section.
Transverse Shear
The shearing stress developed along cross section of a beam to resist transverse shear, having a maximum value at the neutral axis and decreasing nonlinearly toward the outer faces.
Vertical Shearing
The shearing stress developed to prevent slippage along longitudinal planes of a beam under transverse loading, equal to any point to the vertical shearing stress at that point. Also called LONGITUDINAL SHEARING STRESS
Horizontal Shearing
A formula defining the relationship between bending moment, bending stress, and the cross sectional properties of a beam. Bending stress is directly proportional to bending moment and inversely proportional to the moment of inertia of a beam section.
Flexure Formula
The sum of the products each element of an area and the square of its distance from a coplanar axis of rotation. Moment of inertia is a geometric property that indicates how the cross-sectional area of structural member is distributed and does nit reflect the intrinsic physical properties of a material.
Moment of Inertia
A geometric property of a cross section, defined as the moment of inertia of the section divided by the distance from the neutral axis to the most remote surface.
Section Modulus
The buckling of structural member induced by compressive stresses acting on slender portion insufficiently rigid in the lateral direction.
Lateral Buckling
Lines depicting the direction but not the magnitude of the principal stresses in a beam.
Stress Trajectories
A graphic representation of the variation in magnitude of the external shears present in a structure for a given set of transverse loads and support conditions concentrated loads produce external shears which are constant in magnitude between the loads uniformly distributed loads produce linearly varying shears.
Shear Diagram
A graphic representation of the variation in magnitude of the bending moment present in the structure for a given set of transverse load and support conditions. The overall deflected shape of a structure subject to bending can often be inferred from the shape of its moment diagram.
Moment Diagram
Produce bending moments which vary linearly between loads.
Concentrated Loads
Produce parabolically varying moments
Uniformly Distributed Loads
A net resultant of shear forces that acts vertically upward on the left part of the structure being considered.
Positive Shear
A net resultant of shear forces that acts vertically downward on the left part of the structure being considered.
Negative Shear
A bending moment that produces moment that produce a concave curvature at a section of a structure.
Positive Moment
A point at which a structure changes curvature from convex to concave or vice versa as it deflects under a transverse load: theoretically an internal hinge and therefore a point of zero moment.
Inflection point
A bending moment that produces a convex curvature at a section of a structure.
Negative moment
A beam resisting on a simple supports at both end which are free to rotate and have no moment resistance. As with any statically determinate structure, the values of all reactions, shears, and moments for a simple beam are independent of its cross sectional shape and material.
Simple beam
A projecting beam supported at only one fixed end.
Cantilever beam
A beam or other rigid structural member extending beyond a fulcrum and supported by a balancing member or a downward force behind the fulcrum.
Cantilever
A simple beam extending beyond one pf its supports. The overhanging reduces the positive moment at midspan while developing a negative moment at the base of the cantilever over the support.
Overhanging beam
A beam having both ends restrained against translation and rotation. The fixed ends transfer bending stresses, increase the rigidity of the beam and reduces its maximum deflection
Fixed end beam
A beam extending over more than 2 supports in order to develop greater rigidity and smaller moments than a series of simple beams having similar spans and loading. Both fixed end continuous beams are indeterminate structures for which the values of all reactions, shears and moments are dependent not only on span and loading but also on cross sectional shape and material.
Continuous beam
The part of the beam that is thickened or deepened to develop greater moment resistance. The efficiency of a beam can be increased by shaping its length in response to the moment and shear values which typically vary along its longitudinal axis.
Haunch
A simple beam supported by the cantilevers of two adjoining spans with pinned construction joints at points of zero moment. Also called HUNG SPAN
Suspended Span
The distance between inflection points in the span of a fixed end or continuous beam, equivalent in nature to the actual length of simply supported beam.
Effective Length
A relatively slender structural member designed primarily to support axial, compressive loads, applied at the member ends.
Column
A stiff vertical support especially a wooden column in timber framing.
Post
The sudden lateral or torsional instability of a slender structural member induced by the action of a compressive load. Buckling can occur well before the yield stress of the material is reached.
Buckling
The axial load at which a column begins to deflect laterally and becomes unsuitable.
Buckling
The maximum axial load that can theoretically be applied to column without causing it to buckle. The critical buckling load for a column is inversely proportional to the square pf its effective length and directly proportional to the modulus of elasticity of the material and to the moment of inertia of the cross section. Also called EULER BUCKLING LOAD
Critical Buckling load
The critical point at which a column carrying its critical buckling load, my either buckle or remain undeflected. The column is therefore in a state of neutral equilibrium.
Bifurcation
The critical buckling load for a column divided by the area of its cross section .
Critical buckling stress
The ratio of the effective length of a column to its least ratio of gyration.
Slenderness ratio
The radial distance from any axis to a point at which the mass of a body could be concentrated without altering the moment of inertia of the body about that axis.
Radius of Gyration
A slender column subject to failure by buckling rather than crushing.
Long column
A thick column subject to failure by crushing rather than buckling.
Short Column
A column having a mode of failure between that a short column and a long column, often party inelastic by crushing and partly elastic by buckling,
Intermediate column
The amount by which an axis deviates from another parallel axis.
Eccentricity
An additional moment developed in a structural member as its longitudinal axis deviates from the line of action of a compressive force equal to the product of the load and the member deflection at any point.
P-delta Effect
The proposition that a compressive load should be located within the middle third of a horizontal section of a column or wall to prevent tensile stresses from developing in the section.
Middle third rule
The distance between inflection points in a column subject to buckling load. When this portion of a column buckles the entire column falls.
Effective Length
A set of tensile and compressive stresses resulting from the superposition of axial and bending stresses at a cross section of a structural member, acting in the same direction and equal at any point to their algebraic sum.
Combined Stresses
