structural Question and Answer Samples and Techniques
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structural
Question and Answer Samples and Techniques
The amount of force, N
magnitude
It refers to the orientation of its path or line of action
direction
It is usually described by the angle that the line of action makes with
some reference.
Refers to the manner in which it acts along its line of action.
sense
Stress at which 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.
Allowable stress/allowable unit stress/ or working stress
The range of unit stresses for which a material exhibits elastic deformation
Elastic range
Distance from center of moment to force, shortest or perpendicular distance from the center f moment to line of action.
Moment arm
Force x distance
moment
Moment can be about any point called CENTER OF MOMENT
Example is a beam supporting a column
Concentrated load
A series of uniform concentrated loads, or more uniformly spaced concentrated load
Uniform loads
Varying load, moment load
Other loads
Pulls away from a joint
tension
Pulls towards joint
compression
For connections
shear
ASTM
American Society for Testing and Materials
ACI
American Concrete Institute
According to ACI code, the strain in concrete reaches _____________, it begins to crack.
0.003, 3/1000 (mm)
AISM
American Institute for Steel Construction
If a grade 60 steel (fy=60 ksi=414 Mpa) reaches a strain ____________, it begins to crack.
0.0021 (2.1 mm)
A graphic representation of the relationship between unit stress values and the corresponding unit strain for a specific material.
Stress-Strain Diagram
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
He stress wherein the deformation increases without any increase in the load, the material at some portion shows a decrease in its cross section.
Yield point
The maximum stress that can be attained immediately before actual failure or rupture.
Ultimate strength
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.
The property of material that causes it to rupture suddenly with little evident deformation. Lack the plastic behavior of the ductile materials.
brittleness
The property of the material that enables it to undergo plastic deformation after being stressed beyond the elastic limit and before rupturing.
Ductility Ductility is a desirable property of a
structural material since plastic behavior is an indicator of reserve strength and can serve as a visual
warning of impeding failure.
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 a material to regain and rebound to original shape when the lad is released.
malleability
The property of a material that enables it to absorb energy before rupturing, represented by the areas under the stress-strain curve derived from a tensile test of the material.
toughnessDuctile materials are tougher that
brittle materials
A coefficient of elasticity of a material expressing the ration between a unit stress and the corresponding unit strain caused by the stress.
Modulus of elasticity
Also called, COEFFICIENT OF ELASTICITY, ELASTIC MODULUS
The inelastic strain remaining in a material after complete release of the stress producing deformation.
Permanent set
The behavior an increased rate of load application can cause in normally ductile material.
Strain-Rate effect
the brittle behavior low temperatures can cause 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 continued application of stress or prolonged exposure to heat.
Creep
Creep deformation in concrete structure continues over time and can be significantly greater that
the initial elastic deflection.
The weakening or failure of material at a stress below the elastic limit when subjected to a repeated series of stresses.
Fatigue
Structural properties of A36 Steel : modulus of elasticity :
29,000 Ksi
Weight:Water = 1000kg/meter cubeSteel = 7850kg/ meter cube
Concrete = 2400kg/ meter cube
Weight = density x volume
The act f 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.
Axial force
Also called AXIAL LOAD
The act of shortening or state of being pushed together, resulting in the reduction in size or volume of an elastic body.
Compression
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.
Stress Also called UNIT STRESS
The axial stress that develops at the cross section of an elastic body to resist the collinear tensile forces tending to elongate it.
Tensile stress
The elongation of 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 test specimen after in tensile test.
Elongation
A measure of ductility of a material, expressed as the percentage increase 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.
Tensile strength
The deformation of a body under the action of an applied force.
Strain
Strain is a dimensionless quantity equal to the ratio of the change in size and shape to the original size and shape of a stressed element.
An instrument for measuring minute deformation in test specimen caused by tension, compression, bending or twisting.
Stain gauge
Also called EXTENSOMETER
A coefficient of elasticity of material expressing the ratio of longitudinal stress to the corresponding longitudinal strain caused by the strain.
Young’s Modulus
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 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 f the body to slide relative to an adjacent part in a direction parallel to their 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 n a horizontal plane and vise versa.
Shearing force
The force per unit area developed along a section of an elastic body to resist a shear force.
Shearing stress
A coefficient elasticity of a material, expressing the ratio between shearing stress and the corresponding shearing strain produced by the strain.
Shear Modulus of Elasticity
Also called MODULUS OF RIGIDITY, MODULUS OF TORSION
The bowing of an elastic body as an external force is applied transversely to its length. It enables a load to be channeled in a direction perpendicular to its application.
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 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 fire and corrosion. Measured from the surface of the reinforcement to outer surface of the concrete section.
Cover
The adhesive for per unit area f 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 inadequate embedment length.
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 flexural concrete member at a point of maximum stress, a point of inflection or a point 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 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 the 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 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
The 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 a spanning member deviates form 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 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 the 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 the longitudinal planes of a beam under transverse loading, equal to any point to the vertical shearing stress at the point.
Horizontal shearing / longitudinal shearing stress
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 of Modulus
The buckling of a 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
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 f 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 produces concave curvature at a section of a structure.
Positive moment
A point which a structure changes curvature from convex t concave r vise versa as it deflects under a transverse load.
Inflection point
A bending moment that produces a convex curvature at a section f a structure.
Negative moment
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 f its support.
Overhanging beam
A beam having both ends restrained against translation and rotation.
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.
Continuous Beam
A beam resisting on simple supports at both ends which are free to rotate and have mo moment resistance.
Simple beam
The values of all reactions, shears, and moments for a simple beam
are independent f its cross sectional shape and material.
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