STRUCTURAL SYSTEMS (spd) Flashcards
properties of sections
1 area 2 centroid 3 statical moment 4 moment of inertia 5 section modulus 6 radius of gyration (ss)
The rate of changes of velocity, usually expressed a fraction of percentage of g, the acceleration of gravity.
acceleration(ss)
A substance, such as calcium chloride, added to a concrete mix to speed up its setting and strength development.
accelerator(ss)
A seismological instrument which is normally inoperative, but becomes activated when subject to strong earth motion, records the earth motion, and then shut off.
accelerograph(ss)
The pressure exerted by retained earth against retaining wall.
active pressure(ss)
A prepared substance added to concrete to alter or achieve certain characteristics.
admixture(ss)
Earthquake following the occurrence of a large earthquake, or main shock. The magnitude of an aftershock is usually less than that of the main shock.
Aftershock(ss)
The chemically inert element of concrete, usually consisting of sand, gravel, and/or other granular material.
aggregate(ss)
The incorporation of tiny air bubbles into concrete to improve its workability and resistance to frost.
air entrainment(ss)
A membrane enclosing a pressurized occupied space, which must be held down to its foundation.
air-supported structure(ss)
The maximum units of stress permissible in a structural member. It is called working stress
allowable stress(ss)
An increase in a building’s reponse to earthquake ground motion, resulting from the building’s period coinciding with that of the ground shaking, or other causes.
amplification(ss)
A device used to measure wind speed.
anemometer(ss)
The steepest angle with the horizontal at which a pile of loose earth will stand without sliding.
angle of repose(ss)
The most usual welding process used in building construction.In which intense heat is produce by an electric arc between the numbers to be joined and a metal wire or rod, called electrode
arc welding(ss)
A curve structure in which the internal stresses are essentially compression.
arch(ss)
The arbitrary limits which define the boundaries between the different states of rigidity or fluidity of fine-grained soils.
Atterberg limits (ss)
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.
axial load (ss)
Reinforced concrete design in which there is simultaneous crushing of concrete and yielding of the reinforcing steel. To assure that yielding of the steel occurs before crushing of the concrete, the amount of reinforcing is limited to 75 percent of that which would produce a balanced design.
balanced design (ss)
The total design lateral force or shear at the base of a structure.
base shear (v) (ss)
The fastest mile wind speed which has a 2 percent probability of occurring in any one year measured at a point 33 feet (10 meters) above ground
basic wind speed (ss)
Reference points offset a given distance from the building line and set prior to excavation
batter boards (ss)
A structural member which supports loads perpendicular to its longitudinal axis.
beam (ss)
the load per unit area which can be safely support by the ground.
bearing capacity (ss)
A pile which supports a vertical load.
bearing pile (ss)
A wall which supports any vertical load in addition to its own weight.
bearing wall (ss)
In seismic design , a structural system without a complete load carrying frame.Gravity loads are resisted by bearing walls or bracing systems, and lateral loads are resisted by shear walls or braced frames,Bearing wall systems are designed for relatively high seismic forces.
bearing wall systems (ss)
A structural steel connection using high-strength bolts, in which some slip can occur and bearing stresses are considered.
bearing-type connection (ss)
An end-bearing pile constructed by pouring concrete into a drilled shaft, the bottom of which is enlarged (belled) to provide a larger bearing area.
belled caisson (ss)
The algebraic sum of the moments of all forces that are one side of a given cross-section of a beam
bending moment (ss)
The movement of water to the surface of freshly cast concrete
bleeding (ss)
A horizontal reinforced masonry beam, usuallt built integrally with a masonry wall.
bond beam (ss)
most common sub surface exploration.
boring , test pit (ss)
A vertical truss used to resist lateral forces
braced frame (ss)
Cross braces used between joist to stabilize them
bridging(ss)
Describing a material or structural system which tends to fail suddenly without warning when subject to high stresses, as opposed to a ductile material or system, which can absorb energy without failure
brittle
To crush and spread the head of a wood file by driving with a hammer.
broom
In seismic design, a structural system with and essential complete frame providing support for gravity loads.Lateral loads are resisted by shear wall or braced frames. Building frame systems are designed for seismic forces which are lower than those for bearing wall systems.
building frame system
Seismic coefficient based on the building’s seismic zone factor and soil type.
ca & cv
A curve structure in which the internal stresses are pure tension.
cable roof
A waterproof box-like structure in which construction work can be performed underwater. Also a pile constructed by pouring concrete into a drilled shaft
caisson
The most common accelerating admixture used for concrete.It can be used safely in amount up to 2 percent of Portland cement weight.
calcium chloride
A ratio used to determine the bearing capacity of a soil, based on a standard test.
California bearing ratio (CBR)
A beam that is restrained against rotation at one end and free at the other.
cantilever beam
An exterior column footing joined by a concrete beam to an interior column footing. It is also called a strap footing.
cantilever footing
A retaining wall in which the stem heel, and toe act as cantilever slabs
cantilever wall
The curve assumed by a cable hung between two supports, when the only load acting on it is its own weight. The stresses in the cable are pure tension
catenary
The combined height, exposure, and gust factor used in wind design.
ce
The point in a cross-section where all of the area may be considered concentrated without affecting the moment of the are about any axis. For symmetrical shapes, the centroid is the geometric center of the shape.
centroid
A type of diagonal bracing in which one end of each brace frames into a beam-column joint and other frames into a beam. There are two configurations.V-bracing and inverted-V- bracing.Because of various potential problems with chevron bracing the bracing members must be designed for increased seismic loads.
chevron bracing
compose of smaller particle that have some cohesion or tensile strength, and are plastic in behavior.
clay
four groups of soil
clay silt organic sand & gravel
A group of piles
cluster
whose line of action all lies with the same plane.
co planar forces
The ratio of the maximum frictional force between two bodies to the normal (perpendicular) for pressing the surfaces together.
coefficient of friction
The ratio of unit to temperature change, which is constant for a given material.
coefficient of the thermal expansion
A joint formed when a concrete surface hardens before the next batch is placed against it.
cold joint
A horizontal tie beam connecting two opposing rafter at a level above the wall plates.
collar beam
A member which collects seismic load from the diaphragm to which it is attached and delivers it to a shear-resisting element. Also called a strut or drug strut.
collector
those whose vectors lies along the same straight line
collinear forces
A footing supporting two or more columns.
combined footing
One of two or more forces which will produce the same effect on a body as a given force.
component
A steel beam and concrete slab connected so that they act together as a single structural unit to resist bending stresses.
composite beam
Steel floor decking with embossed ridges, bonded to a concrete slab so that they act together as a single structural unit.
composite deck
Stress in which the particle are pushed together and the member tends to shorten
compression
Caused material to shorten and widen
compressive force
Reinforcing steel embedded in the compression face of a reinforced concrete beam.
compressive reinforcement
A load which acts at one point on a structure.
concentrated load
A braced frame in which the center lines of intersecting members meet at a point and whose members are therefore subjected primarily to axial forces.
concentric braced frame
Describing the condition when the lines of action of several forces pass through a common point
concurrent
whose lines of action meet at a common point.
concurrent forces
The joint between two successive concrete pours. Construction joints are usually located where the shear is minimum, such as at the midspan of beams.
construction joint
A groove in a concrete structure made to predetermine the location of cracks.
control joint
A compression test of hardened concrete which has been cut from the structure.
core test
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.
couple
In wind design, a pressure coefficient for the structure or portion of the structure under consideration.
cq
Continued deformation of a structural member with time, with no increase of load.
creep
Maintaining concrete at the proper moisture and temperature after it is cast.
curing
A factor used to modify the allowable stress in bending for the curved portion of glued laminated members.
curvature factor
The decrease of vibration caused by the absorption of energy.Building contain a number of elements,both structural and nonstructural,which absorb energy during an earthquake and thereby diminish the earthquake-induced vibration.
damping
The movement of a beam from its original location when load is applied to it
deflection
The change in size of a body caused by external forces. It is also called strain.
deformation
The separation of lamination of a glued laminated beam caused by failure of adhesive.
delamination
First steps in designing a foundation .
determine the bearing capacity of underlying soil.
A horizontal system which distributes lateral forces, caused by wind or earthquake, to the vertical resisting elements
diaphragm
The boundary element of a diaphragm or shear wall which is assumed to resist axial stresses, analogous to a flange of a beam.
diaphragm chord
Unequal settlement of the various parts of a building, which may cause excessive stresses in the structural frame or tilting of the building
differential settlement
Horizontal or vertical movement of a structural element resulting from applied seismic or other load.
displacement
Describing a bolted joint which has two shearing planes through the bolts.
double-shear
A member which collects a seismic load from diaphragm to which it is attached and delivers it to a shear resisting element. also called a collector or strut.
drag strut
The horizontal movement of a structure when subject to wind or earthquake forces.
drift
An end-bearing pile, the bottom of which may be belled, which is constructed by pouring concrete into a drilled shaft.
drilled caisson
A vertical shaft drilled into the ground and filled with concentrate, which supports building loads by skin friction.
drilled pile
In seismic design, a combination of moment resisting frames and shear walls or braced frames
dual systems
The ability of a material to undergo large deformations without fracture.
ductility
A method for determining earthquake forces in which a mathematical model of the structure is develop and then subjected to appropriate ground motions. This procedure is always accepted for design.
dynamic lateral force procedure
A braced frame in which at least one end of which brace is eccentric to the beam-column joint or the opposing brace. The intent is to make the braced frame more ductile and therefore able to absorb a significant amount of energy without buckling the braces.
eccentric braced frame (EBF)
A longitudinal load which acts at a distance from a member’s centroid, thereby producing bending moment in addition to axial stress.
eccentric load
In reinforced concrete design, the distance from the extreme compression fiber to the centroid of the tension reinforcement.
effective depth (d)
The material will begin to change length at a faster ratio than the applied force
elastic limit
The unit stress for a material, below which Hooke’s Law applies.
elastic limit
A pile whose load is supported by firm soil or rock under the pile tip.
end-bearing pile
A dynamic formula used to determine the capacity of driven piles.
engineering news formula
The projection of the focus, where rock slippage begins, on the ground surface
epicenter
A force equal in magnitude to the resultant, but opposite in direction and on the same line of action as the resultant.
equilibrant
Is said to exist when the resultant of any number of forces acting on a body is zero
equilibrium
Structures or buildings which must be safe and usable for emergency purposes after an earthquake or severe windstorm. Such facilities include hospitals and fire and police stations.
essential facilities
A basic equation which applies to all columns and gives the maximum stress a slender column can resist without failing by sudden buckling.
Euler’s equation
A fine grained cohesive soil which undergoes a large volume changes in moisture content.
expansive soil
The ratio of the ultimate strength of a material to its working stress.
factor of safety
The Boundary between adjacent rock plates along which movements may take place during an earthquake, such as the San Andreas Fault in California.
Fault
The location that is restrained(fixed) against rotation at both ends.
fixed end beam
A concrete slab reinforced in two directions which brings its load directly to supporting columns without any beams, girders, column capitals (widened tops of columns), or drop panels (thickened slab around columns)
flat plate
A concrete slab reinforced in two directions which brings its load directly to supporting columns without any beams or girders, usually requiring column capitals (widened tops of columns) and drop panels (thickened slab around columns).
flat slab
Another term for bending.
flexure
A structural roof system consisting of inclined planes which support each other and function as deep beams.
folded plate
A foundation which spreads the load over a large area of soil. It is also called a spread footing
footing
A push or pull exerted on an object. The description of a force includes its magnitude ,direction, and point of application.
force
Any action applied to an object.
force
A diagram used to graphically determine the resultant of two or more forces.
force polygon
The part of a building s load to the underlying soil.
foundation
A metal device used for connection members in wood frame construction.
framing anchor
A diagram obtained by making an imaginary cut through a structure and applying the equation of equilibrium to the remaining portion, called the “free body.”By this means, the internal forces of a structure may be determined.
free body diagram
Referring to soil which is easily crumbled or reduced to powder.
friable
Uplift of the soil surface or foundation caused by freezing of moisture in the soil.
Frost heave
The time it takes for a structure to go through one complete back-and-forth motion under the action of dynamic loads. also called period or natural period.
fundamental period of vibration (t)
A main beam which supports secondary beams.
girder
A framework if horizontal member used to spread a structural load over a large area.
grillage
A weld placed between two butting pieced of metal to be joined.
groove weld
The principal cause of structural damage, injury and loss of life during an earthquake. The provisions of the Uniform Building Code provides resistance to earthquake ground shaking, without settlement, slides, subsidence, or faulting in the immediate vicinity of the structures.
ground shaking
A high-slump concrete, consisting of Portland cement, sand, hydrated lime, water and sometimes pea gravel.
grout
A pneumatic applied concrete shot into place by means of compresses air. this method may be used for both repair work and new construction especially in difficult locations or where the section occur.
gunite
Referring to construction in which fire resistance is obtained by using wood structural members of specified minimum sizes
heavy timber
A type of cement (ASTM type lll) which provide earlier strength in concrete than ordinary cements. It is used when form must be removed quickly or when the structure must be put into service quickly.
high-early-strength-concrete
The deformation (strain) is directly proportional to the stress, up to a certain point.
Hooke’s Law
The physical law that states that up to a certain unit stress, called the elastic limit, unit stress is directly proportional to unit strain
Hooke’s Law
A horizontal member which extends around the circumference of a dome.
hoop
A horizontal truss system which distributes lateral forces, caused by wind or earthquake, to the vertical resisting elements.
horizontal bracing system
A severe tropical storm which occurs mainly along the coasts of the Gulf of Mexico and the South Atlantic. The design of buildings to resist wind in accordance with building code requirements includes the effects of hurricanes.
hurricane
The chemical reaction which combines cement and water to form a hard, solid mass
hydration
The pressure exerted by a liquid against every surface it contacts.
hydrostatic pressure
A thin shell saddle-shaped surface formed by moving a vertical parabola with downward curvature along and perpendicular to another parabola with upward curvature.
hyperbolic paraboloid
The location in the earth’s crust where rock slippage begin during an earthquake. Also called the focus.
hypocenter
A symbol for moment of inertia
I
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 substitute for standard compression tests.
impact hammer test
The sudden application of load from a moving object, such as a crane or elevator, which causes stresses much greater than those caused by a static load.
impact load
A factor used in earthquake and wind design, whose value varies between 1.0 and 1.5. This provides that certain essential facilities, such as hospitals and fire and police stations, be design for seismic and wind forces greater than normal. In this way, such emergency faclities are expected to be safe and usable following an earthquake or severe windstorm.
importance factor (i)
Describing a material which does not return to its original size and shape when the load is removed, but retain permanent deformation. also describes structural behavior in which member are stressed above the yield point.
inelastic
The effect of an earthquake on people and structures at a particular place, as measured by the Modified Mercalli scale,Intensity refers to an earthquake’s effect,while magnitude refers to an earthquake’s energy.
intensity
Map contour connecting points of equal intensity for a given earthquake.
isoseismals
A short rafter between hip rafter and eave or between valley and ridge.
jack rafter
A method of placing piles using high-pressure water jets.
jetting
A shop fabricated steel truss that supports evenly-spaced steel joist along its top chord.
joist girder
An effective length factor used in the design of structural steel columns.
K
A test to determine the workability of fresh concrete.
Kelly ball test
A lower layer of fine particle that floats to the surface of wet concrete.
laitance
A roof structure comprising a series of parallel arches, skewed to the axes of the building, which are intersected by another series of skewed arches, so that they interact with each other
lamella
The part of the structural system assigned to resist lateral forces from wind or earthquake.
lateral force resisting system
Any horizontal load on a building,including the load from wind or earthquake.
lateral load
A horizontal member supporting joists.
ledger
A flat plate cast at grade around columns and then lifted to position with hydraulic jacks.
lift slab
A line parallel to and aligned with force.
line of action
In seismic design ,the content at which the soil starts to change from plastic to semi liquid state.
liquid limit
The vertical load caused by the use and occupancy of a building not including wind, earthquake, or dead loads.
live load
A force applied to a body.
load
Wood has been sawn into construction members.
lumber
A symbol for bending moment.
M
The amount of energy released by an earthquake,as measures=d by the Richter scale.Magnitude refers to an earthquake’s energy, while intensity refers to an earthquake’s effects.
magnitude
A solid core is used in driving a shell pile into the ground. When the driving is complete, the mandrel is removed and the shell if filled with concrete.
mandrel
