Terms
Axial loading
load distributed along a linear plane (e.g. column, pile, bracing)
Bending moment
the sum of (force) * (perpendicular distance) to the left of any location along the span of a beam (or the sum of areas in a shear diagram)
= M/S where, S = bd2/6
Centroid
center of gravity, the point within an object from which the force of gravity appears to act. An object will remain at rest if it is balanced on any point along a vertical line passing through its center of gravity. In terms of moments, the center of gravity of any object is the point around which the moments of the gravitational forces completely cancel one another.
Combined loading
axial + bending loads
Elasticity
stiffness of a material
Epicenter
point where an earthquake surfaces
Equilibrant
a vector that is equal and opposite to the resultant
Fulcrum
pivot, or center of moment
Hypocenter
focus, or origin of an earthquake
Maximum shear
defines the area of a beam
Maximum moment
defines the depth of a beam
Maxwell diagram
a graphic method to solve a truss, using Bowes Notation
Modulus of Elasticity (E)
the stress to strain ratio of a material; a measure of a material’s resistance to deformation, or its stiffness. Hint: a stiffer material will have a higher elastic modulus.
Moment
an unbalanced force that causes rotation about a turning point, or fulcrum. Moment = (Force) * (Perpendicular distance from fulcrum)
Moment arm
perpendicular distance from a fulcrum, or pivot
Moment of Inertia (I)
a term used to describe the capacity of a cross-section to resist bending. It is always considered with respect to a reference (usually centroidal) axis.
Resultant
a vector sum of forces, or loads
Richter scale
a measure of an earthquake’s magnitude
Shear
the sum of forces to the left of any location along the span of a beam
shear determines area; If shear = 0, then this defines the maximum moment. Shear area = b*d
Slenderness Ratio
The ratio between height or length of a structural element (such as a column, or strut) and the width or thickness of the element.
Hint: The higher the slenderness ratio, the more slender the structural element is. How slender a structural element is allowed to be depends upon the material it is made from. Steel can be more slender than concrete
Strain Gauge
A change of length or shape that measures strain
Stress
the force (load) exerted by a given pressure, P, over a given area, A.
F = P/A
Thermal stress
= (modulus of elasticity) * (coefficient of linear expansion) * (change in temperature, in oF)
Thermal strain
= (coefficient of linear expansion) * (change in temperature, in oF)
Transmissibility
a force sliding along a line of action (L.O.A.) without changes in the reactions
Truss
a structure that controls tension and compression
Acronyms
Loads
DL = Dead load
E = Seismic or earthquake load
F = Load do to fluids, such as an elevated water tank
Fa = Flood load
H = Load due to lateral earth pressure
LL = Live load
Lr = Roof live load
S = Snow load
R = Rain load
WL = Wind load
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