2 Flashcards
braced frame
A vertical truss used to resist lateral forces.
frost line
The expected maximum depth of frost penetration in the ground in a given area.
post-and-beam system
A simple structural system consisting of beams simply supported on posts.
irregular structure
In seismic design, a structure which has significant physical discontinuities in plan or vertical configuration or in its lateral force resisting system. Since irregular structures have less favorable and predictable seismic response characteristics than regular structures, specific design requirements are prescribed for each type of irregularity.
couple
Two forces equal in magnitude, but opposite in direction, and acting at some distance from each other. The moment produced by a couple is equal to the value of one force multiplied by the distance between the two forces.
gravel
A coarse granular material, with particles varying from about 3” to 3/16”.
compacted fill
Fill which has been densified by the application of pressure, usually by mechanical equipment, in order to increase its strength and stability and reduce its settlement. Properly compacted fill is often suitable for the support of building footings.
groove weld
A weld placed between two butting pieces of metal to be joined.
bolt
A metal fastener with a head at one end and external thread at the other end to receive a nut.
drilled pile
A vertical shaft drilled into the ground and filled with concrete, which supports building loads by skin friction.
web
The portion of a truss between the chords, or the portion of a beam between the flanges.
stirrup
A vertical steel bar, usually U-shaped, used to reinforce a reinforced concrete beam where the shear stresses are excessive.
accelerator
A substance, such as calcium chloride, added to a concrete mix to speed up its setting and strength development.
cofferdam
A watertight, temporary structure used under water, in which construction work can be performed.
axial load
A longitudinal load which acts at the centroid of a member and perpendicular to its cross-section, thereby producing uniform tensile or compressive stress without any bending.
m
A symbol for bending moment.
reinforcing steel
Round steel bars with surface deformations which are placed in the forms prior to casting of concrete, and which primarily resist tension.
focus
The location in the earth’s crust where rock slippage begins during an earthquake. Also called the hypocenter.
displacement
Horizontal or vertical movement of a structural element resulting from applied seismic or other load.
lintel
A structural member placed over an opening and supporting construction above.
heavy timber
Referring to construction in which fire resistance is obtained by using wood structural members of specified minimum sizes.
size factor
A factor used to reduce the allowable bending stress for wood beams deeper than 12”.
air entrainment
The incorporation of tiny air bubbles into concrete to improve its workability and resistance to frost.
web members
The interior members of a truss, which connect the chords.
differential settlement
Unequal settlement of the various parts of a building, which may cause excessive stresses in the structural frame or tilting of the building.
cable roof
A curved structure in which the internal stresses are pure tension.
silt
A fine-grained soil, whose particles are larger than clay and smaller than sand.
dry pack
To pack a damp concrete mixture into a confined space.
strain
The change in size of a body caused by external forces. It is also called deformation.
ultimate strength
The maximum unit stress that can be developed in a material.
statical moment
The product of an area and the distance from the centroid of the area to a given axis.
deformation
The change in size of a body caused by external forces. It is also called strain.
trussed rafter
A prefabricated, lightweight wood truss used to support roof loads and other small structures.
eccentric load
A longitudinal load which acts at a distance from a member’s centroid, thereby producing bending moment in addition to axial stress.
retaining wall
A wall which resists the lateral pressure of retained earth or other material.
stub girder system
A steel framing system in which beams sit on top of a girder and short lengths of “stub girders” the same depth as the floor beams are welded to the top of the girder to provide for composite action.
Vierendeel truss
A truss with no diagonals.
hyperbolic paraboloid
A thin shell saddle-shaped surface formed by moving a vertical parabola with downward curvature along a perpendicular to another parabola with upward curvature.
impact hammer test
A nondestructive test to determine the strength of hardened concrete, by measuring the rebound of a plunger after striking the concrete surface. This test is not accurate enough to be a substitute for standard compression tests.
concentrated load
A load which acts at one point on a structure.