ARE Structural Systems Flashcards
Acceleration
The rate of change of velocity usually expressed as a fraction or percentage of g, the acceleration of gravity
Accelerograph
A seismological instrument that is normally inoperative, but becomes activated when subject to strong earth motion, records teh earth motion, and hten shuts off.
Active Pressure
The pressure exerted by retained earth against a retaining wall.
Admixture
A prepared substance added to concrete to alter or achieve certain characteristics
Aggregate
The chemically inert element of concrete, usually consisting of sand, gravel and/or other granular material.
Air-Supported Structure
A membrane enclosing a pressurized occupied space, which must be held down to its foundation.
Allowable Stress Design
The design method used for most reinforced concrete design until the middle of the 1960s. Still used for steel design. Largely replaced by strength design.
Arch
A curved structure in whic hthe internal stresses are essentially compression.
Axial Load
A longitudinal load that acts as the centroid of a member and perpendicular to its cross section
Balloon Framing
A method of framing wood stud walls, in which the studs are continuous for the full height of the building, which is usually two stories.
Seismic/Base Isolation
A method of isolating a structure from the ground by specially designed bearing and dampers that basorb earthquake forces.
Beam
A structural member that supports loads perpendicular to its longitudinal axis.
Bearing Wall
A wall that supports any vertical load in addition to its own weight.
Bending Moment
The algebraic sum of the moments of all forces that are on one side of a given cross section of a beam.
Braced Frame
A vertical truss used to resist lateral forces.
C
A standard designation for a structural steel American Standard channel
Cable Roof
A curved structure in which the internal stresses are pure tension.
Camber
A curve built into a structural member to compensate for deflection
Cantilever Beam
A beam that is restrained against rotation at one end and free at the other
Cantilever /Strap Footing
An exterior column footing joined by a concrete beam to an interior column footing
Cantilever Wall
A retaining wall in which the stem, heel, and toe act as cantilever slabs.
Catenary
The shape assumed by a cable when the only load acting on it is its own weight
Centroid
The point in a cross-section where all of the area may be considered concentrated without affecting the moment of the area about any axis.
Chord
A perimeter member of a truss
Coefficient of thermal expansion
The ration of unit strain to temperature change, which is constant for a given material.
Collector
A member used to collect seismic load from a diaphragm and deliver it to a shear resisting element.
Column
A member, usually vertical, which is subject primarily to axial compressive load.
Column Footing
A spread footing, generally square or rectangular in plan, used to support a single column.
Combined Footing
A footing supporting two or more columns
Component
One of two or more forces that will produce the same effect on a body as a given force.
Composite Beam
A steel beam and a concrete slab connected so that they act together as a single structural unit to resist bending stresses.
Composite Deck
Steel floor decking with embossed ridges, bonded to a concrete slab so that they act together as a single structural unit.
Compression
Stress that tends to shorten a member to crush it.
Compressive Reinforcement
Reinforcing steel embedded in the compression face of a reinforced concrete beam
Concentrated Load
A load that acts at one point on a structure.
Concrete
A mixture of fine and coarse aggregates, portland cement, and water
Concurrent
Describing the conditions when the lines of action of several forces pass through a common point
Continuous Beam
A beam that rests on more than two supports
Core Test
A compression test of hardened concrete that has been cut from the structure.
Counterfort Wall
A retaining wall in which the stem and base are connected at intervals by transverse walls called counterforts
Couple
Two forces equal in magnitude, but opposite in direction, and acting at some distance from each other.
Creep
Continued deformation of a structural member with time, with no increase of load.
Curing
Maintaing concrete at the proper moisture and temperature after it is cast
Curvature Factor
A factor used to modify the allowable unit stress in bending for the curved portion of glued laminated members.
Cylinder Test
A test to determine the compressive strength of concrete by subjecting a standard cylinder of hardened concrete to compression in a testing machine
Dread Load
The vertical load due to the weight of all permanent structural components of a building, such as walls, floors, roofs, and fixed service equipment
Deflection
The movement of a beam from its original location when load is applied to it
Diaphragm
The horizontal floor or roof system that distributes lateral forces caused by wind or earthquake, by functioning as a horizontal girder
Dome
A roof structure whose shape is that of an arch rotated about its vertical axis to form a curved surface
Drift
The horizontal movement of a structure when subject to wind or earthquake force
Drilled / End-Bearing Caisson
An end-bearing pile, the bottom of which may be belled, which is constructed by pouring concrete into a drilled shaft.
Drilled/Friction Pile
A vertical shaft drilled into the ground and filled with concrete, which supports building loads by skin friction
Ductility
As used in earthquake design, the ability of structural systems and materials to deform and absorb energy, without failure or collapse
E
A symbol for modulus of elasticity
Eccentric Load
A longitudinal load that acts at a distance from a member’s centroid, thereby producing bending moment in additional to axial stress
Elastic Limit
The unit stress for a material, below which Hooke’s Law applies
Engineering News Formula
A dynamic formula used to determine the capacity of driven piles
Epicenter
The projection of the focus on the ground surface
Equillibrant
A force equal in magnitude to the resultant, but opposite in direction and on the same line of action as the resultant.
Equilibrium
A state of rest due to balanced forces and balanced moments
Euler’s Equation
A basic equation that applies to all columns and gives the maximum stress a slender column can resist without failing by sudden buckling.
Expansive Soil
A fine-grained cohesive soil which undergoes large volume changes with changes in moisture content
Factor of Safety
The ratio of the ultimate strength of a material to its working stress.
Fault
The boundary between adjacent rock plates along which movement may take place during an earthquake
Fillet Weld
A weld placed in the right angle formed by lapping or intersecting plates and generally subject to shear stress
Fixed End Beam
A beam that is restrained (fixed) against rotation at both ends
Flat Plate
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). A flat slab without column capitals or drop panels
Flat Slab
A concrete slab reinforced in two directions that brings its load directly to supporting columns without any beams or girders, usually requiring column capitals (widened tops or columns) and drop panels (thickened slab around columns).
Flexure
Bending
Focus/Hypocenter
The location in the earth’s crust where rock slippage begins during an earthquake
Folded Plate
A structural roof system consisting of inclined planes that support each other and function as deep beams
Force
A push or pull exerted on an object. The description of a force includes its magnitude, direction, and point of application
Frost Line
The maximum depth of frost penetration in the ground expected in a given area
Gabled Frame
A frame consisting of two columns and two inclined beams that meet at the ridge, in which the joint between each column and beam is rigid.
Girder
A main beam that supports secondary beams.
Glued Laminated Beam
An assembly of laminations of lumber in which the grain of all the laminations is approximately parallel longitudinally and fabricated in accordance with certain accepted standards.
Gravity Wall
A retaining wall that depends entirely on its own weight to resist the pressure of the retained earth and provide stability.
Groove Weld
A weld placed between two butting pieces of metal to be joined.
Grout
A high slump concrete, consisting of portland cement, sand, hydrated lime, water, and sometimes pea gravel.
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.
Hoop
A horizontal member that extends around the circumference of a dome.
Hydrostatic Pressure
The pressure exerted by a liquid against every surface it contacts
Hyperbolic Paraboloid
A thin shell saddle-shaped surface formed by moving a vertical parabola with downward curvature along and perpendicular to another parabola with upward curvature
I
- A symbol for moment of inertia
- The importance factor used in earthquake or wind design
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.
Joist
One of a series of small, closely-spaced beams used to support floor, ceiling, or roof loads
Joist Girder
A shop-fabricated steel truss that supports evenly-spaced steel joists along its top chord
K
An effective length factor used in the design of structural steel columns
Kelly Ball Test
A method of measuring the workability to fresh concrete
Kip
A unit of force or weight equal to 1,000 pounds
Ksi
An abbreviation for kips per square inch
L
A standard designation for a structural steel angle
Lamella
A roof structure comprising a series of parallel arches, skewed to the axes fo the building, which are intersected by another series of skewed arches, so that they interact with each other
Lateral Load
Any horizontal load on a building, including the load from wind or earthquake
Lift Slab
A flat plate cast at grade around columns and then lifted to position with hydraulic jacks
Line of Action
A line parallel to and in line with a force
Lintel
A structural member placed over an opening and supporting construction above.
Liquefaction
Transformation of soil into a liquefied state, similar to quicksand, as a result of earthquake vibrations
Live Load
The vertical load caused by the use and occupancy of a building, not including wind, earthquake or dead loads
Load
A force applied to a body
M
A symbol for bending moment
Mat Foundation
A large footing under an entire building, which distributes the building load over the entire area.
Membrane
A thin sheet that can resist tension, but cannot resist compression, bending, or shear
Meridian
A curved line on the surface of a dome, usually circular, which is formed by intersection of a vertical plane with the dome when the plane passes through the top of the dome
Method of Joints
An analytical method for determining the forces in the members of a truss
Method of Sections
An analytical method for determining the forces in the members of a truss
Modified Mercalli Scale
A scale used to measure the intensity of an earthquake
Modulus of Elasticity
Within the elastic limit, the constant ratio of the unit stress in a material to the corresponding unit strain
Modulus of Rupture
The unit bending stress calculated from the flexure formula, for the maximum bending moment resisted by a beam before rupture.
Moment
The tendency of a force to cause rotation about a given point or axis
Moment Diagram
A graphic representation of the value of the bending moment at any point along a beam
Moment of Inertia
The sum of the products obtained by multiplying each unit of area by the square of its distance to the neutral axis
Rigid/Moment-Resisting Frame
A frame with rigid joints, in which the members and joints are capable of resisting vertical and horizontal forces primarily by flexure
Natural Period of Vibration
The time it takes for a structure to go through one complete back and forth motion under the action of dynamic loads
Negative Moment
Bending moment that produces tension in the upper part of a beam and compression in the lower part
Neutral Axis
The line on a beam cross section that has zero bending stress when the beam in loaded
Nonbearing Wall
A wall that supports no vertical load other htan its own weight
Open Web Steel Joist
A shop-fabricated, lightweight steel truss used to span between main members or bearing walls and support roof or floor loads
Overhanging Beam
A beam that rests on two or more supports and has one or both ends projecting beyond the support
P-Delta Effect
The secondary effect on frame members produced by vertical loads acting on a building frame that is laterally displaced by earthquake loads
Pile
An underground wood, concrete, or steel member, usually vertical, and usually driven into place, which is used to support building loads
Plate Girder
An assembly of steel plates or plates and angles which are fastened together to form an integral member
Plate Tectonics
The theory that explains earthquake phenomena
Platform Framing
A method of framing wood stud walls in which the studs are one story in height and the floor joists bear on the top plates of the wall below.
Point of Inflection
The point in a beam or other flexural member where the bending moment changes sign and has a value of zero
Portland Cement
The finely-ground material used as a binder for structural concrete
Positive Moment
Bending moment that produces compression in the upper part of a beam and tension in the lower part
Posttensioning
A method of prestressing concrete in which the concrete is cast and then the steel tendons stressed by jacking
Prestressed Concrete
Concrete that is permanently loaded so as to cause stresses opposite in direction from those caused by dead and live loads
Pretensioning
A method of prestressing concrete in which the tensile force is put into high strength steel wires before the concrete is cast
Proctor Test
A laboratory compaction test to determine the optimum moisture content and density for a soil
Psf
An abbreviation for pounds per square foot
Psi
An abbreviation for pounds per square inch
Punching Shear
Two-way shear that occurs in a flat slab, spread footing, or pile cap
Purlin
A regularly spaced roof beam that spans between girders or trusses
r
A symbol for radius of gyration
R
A numerical coefficient used in earthquake design
Radiographic Inspection
Nondestructive testing of welded joints using x-rays and gamma rays
Radius of Gyration
A term used in column design equal to, where I is the moment of inertia of a member and A is its cross-sectional area
Reactions
Forces acting at the supports of a structure that hold the structure in equilibrium
Redundancy
The ability of part of a structural system to redistribute loads to other parts of the system. Lateral force resisting systems should be as redundant as possible.
Redundant Member
Any truss member not necessary for stability
Reinforced Brick Masonry
A type of wall construction consisting of brick units, usually two tiers, with a solidly grouted space between in which vertical and horizontal reinforcing bars are placed
Reinforced Concrete Block Masonry
A type of wall construction consisting of hollow concrete masonry units, with certain cells continuously filled with grout in which reinforcing bars are embedded
Resolving Forces
Replacing a force with two or more other forces (components) that will produce the same effect on a body as the original force
Response Spectrum
A curve that shows the maximum acceleration of a series of idealized structures when subject to an earthquake
Resultant
One force that will produce the same effect as two or more other forces
Retaining Wall
A wall that resists the lateral pressure of retained earth or other material
Richter Scale
A logarithmic scale used to measure earthquake magnitudes