Chapter 2- Concepts of Construction Flashcards
NFPA 5000: Building Construction and Safety Code, _____ are forces or other actions that result from the weight of all building materials, occupants and their possessions, environmental effects, differential movement, and restrained dimensional changes.
Loads
The internal forces that resist the load are called
Stress and Strain.
__, a term meaning 1,000 pounds, is used in engineering calculations where the number would be so large as to be unwieldy.
KIP
Generally, four types of forces can be applied to a structural member: __, __, __, and __.
compression, tension, torsion, shear.
Today, buildings can be considered as being bought
by the pound
__ loads can be accurately calculated.
Dead
__ loads are indeterminate. The __ load must be estimated based on the projected use of the building and such variables as snow, wind, or rain.
Live
Water weighs __ pounds per gallon, so a 1,000 gallon per minute master stream will potentially add over 4 tons of weight to the building in just 1 minute.
8.34
__ loads are loads that are applied slowly and remain constant.
Static
Two closely related structural frames, the __ __ and the __ __, are also used in buildings to resist lateral wind and earthquake loads (and, more recently, the lateral blast loads from a terrorist’s bomb). ____ ____ uses diagonal memebers for bracing purposes, while ____ _____ uses a special moment connects between columns and beams that resist rotation.
Braced frame, Moment frame
Very tall high-rise buildings are built to take the wind load on the __ __ rather than on the __ __.
Exterior walls, interior core.
A steel beam resting on a masonry wall is an example of a __ __ load.
Concentrated dead.
A safe is a __ __ load.
Concentrated live.
Wood, paper and similar materials are estimated at __ btu/lb.
8000
For plastics and combustible liquids, __ btu/lb is a common estimate, though the caloric value for some of these fuels is much higher.
16000
Under this system, plastics were converted into equivalent pounds on the basis that __ pound of plastics equals __ pounds of wood.
1, 2.
A fire load of 80,000 Btu/sq ft or 10 lbs of ordinary combustibles/sq ft is approximately the equivalent of a __ hour exposure to the standard fire endurance test ASTM E-119, Standard Test Methods for Fire Tests of Building Construction and Materials.
1
Steel, which has a safety factor of __; masonry constructed in place might have a safety factor of __.
2, 10.
Concrete is a relatively inexpensive material that is strong in __ but weak in __.
Compression, tension.
The load carrying capacity of a beam increases by the __ of its depth.
Square
__ can support axial loads but are not designed to handle rotational moments
Trusses
Wooden __ chord trusses are being used for floors and roofs in single family homes, row houses, apartment houses, and smaller office buildings.
Parallel
The top chord of a truss is in __.
Compression
The bottom chord is in __.
Tension
When a truss is __ out, the situation reverses.
Cantilevered
It is more difficult to attach beams to __ columns than to rectangular columns, so less efficient rectangular columns are often used.
Round.
In cast iron construction in buildings, interior columns are usually __, while wall columns (within exterior walls) are __.
Circular, Rectangular.
There are three types of columns, which can be differentiated by the manner in which they generally fail. __ are short, squat columns, which fail by crushing.
Piers
Long, __ columns fail by buckling. In buckling, the column normally assumes an S shape.
Slender
__ columns can fail either way.
Intermediate
Very long, thin columns are known as __ __ columns.
Euler’s Law
The terms panel walls and curtain walls are often used interchangeably to describe non load bearing enclosing walls on framed buildings. Technically, __ walls are one story in height and __ walls are more than one story.
Panel, Curtain.
The __ combines the function of the beam and the column.
Arch
The truss is a beam, and its thrust is straight down the wall or column. In contrast, the thrust of an arch is __.
Outward
When the arch is tied, the thrust is __, but it lacks the triangles that would make it a truss.
Downward
The __ is a shell. It can be considered a three dimensional arch.
Dome
__ domes are formed from a large number of triangles of equal size.
Geodesic
There are two general types of connections:
A building is said to be __ when the elements are connected by simple connectors such as bolts, rivets, or welded joints. These are usually not strong enough to reroute forces if a member is removed, so do not assume loads will be redistributed around the missing member.
Pinned
In a __ __ building, the connections are strong enough to reroute forces if a member is removed.
Rigid Framed
A __ concrete building is rigid framed.
Monolithic
__ concrete buildings may be pinned or may be made monolithic by the use of wet joints in which cast in place concrete unites rods that project from precast sections.
Precast
Steel heated to 1,000 degrees F elongates __ inches per 100 feet.
9.5
Unprotected steel rods and cables ( which fail at __ degrees F) are often used to tie failing buildings together or to provide some additional resistance to earthquake movement.
800
Vertical or horizontal orientation.
Attitude
A load that passes through the centroid of a section under construction and is perpendicular to the plane of the section.
Axial Load
Lightweight steel truss joist.
Bar Joist
A structural member that transmits forces perpendicular to such forces to the reaction points.
Beam
A line of columns in any direction.
Bent
A structural system that uses diagonal members to provide bracing against lateral wind and earthquake loads.
Braced Frame
Diagonal member that supports what would otherwise be a cantilever.
Bracket
Consists of an exterior wythe of brick directly mortared or parked to an inner wythe of concrete masonry unit.
Brick and Block Composite Wall
The quantity of heat required to raise the temperature of 1 pound of water 1 degree F at the pressure of 1 atmosphere and temperature of 60 degrees F.
British Thermal Unit, BTU.
Made of steel plates and angles riveted together, as distinguished from one rolled from one piece of steel.
Built up Girder
Mass of masonry built against a wall to strengthen it. Necessary when a vault or an arch places a heavy load or thrust on one part of a wall.
Buttress
Measured in Btu; the amount of heat required to raise 1 pound of water 1 degree F.
Caloric value
Upward rise.
Camber
A beam supported at one end only, rigidly held in position at the end.
Cantilever beam
A wall built of two wythes separated by a space for rain drainage or insulation.
Cavity or hollow wall
The center point at which a body would be stable, or balance, under the influence of gravity.
Centroid
The outside members (top and bottom) of a truss, as opposed to the inner webbed members
Chord
A structural member that transmits a compressive force along a straight path in the direction of the member.
Column
Built up of different parts, pieces, or materials.
Composite
A wall composed of two or more masonry materials that react together under load.
Composite wall
Direct pushing force, in line with the axis member; the opposite of tension.
Compression
A load acting on a very small area of the structure’s surface; the exact opposite of a distributed load.
Concentrated load
A beam supported at three or more points.
Continuous beam
Any wall at right angles to any other wall; the walls should brace one another.
Cross wall
No external braces involved; bracing is done within the core of the structure.
Core construction
The weight of the building itself and any equipment permanently attached to it or built in.
Dead load
The deformation or displacement of a structural member as a result of loads acting on it.
Deflection
Wall bounding a tenant space.
Demising wall
A floor designed to stiffen a building against wind and other lateral loads such as earthquakes.
Diaphragm floor
A force that is perpendicular to the plane section but does not pass through the center of the section.
Eccentric load
The end of a joist that is cut at an angle to permit the joist to fall out of a wall without damaging the load bearing wall.
Fire cut
The potential fuel available for a fire in a building.
Fire load
The ability of a material to avoid ignition, combustion, and the thermal effects of fire.
Fire resistance
Wall with a fire resistive rating and structural stability that separates buildings or subdivides a building to prevent the spread of fire.
Fire wall
Beam supported at two points and rigidly held in position at both points.
Fixed beam
Made by sandwiching a piece of steel between two wooden beams.
Flitch plate girder
The lower division of a building that serves to transmit and anchor the loads from the superstructure directly to its earth or rock, usually below ground level.
Foundation
Another name for a gusset plate in a lightweight wood truss.
Gang nail
A beam that supports other beams.
Girder
A connection that depends on the weight of the building to hold it in place.
Gravity connection
All of the structural elements of a building and the connections that support and transfer the loads.
Gravity resistance system
A series of closely spaced beams designed to carry a particularly heavy load.
Grillage
A masonry unit that overlaps two or more adjoining wythes of masonry to tie them together.
Header
The rate at which the potential heat in a fuel is released.
Heat release rate (HRR)
When describing wall construction, a wall that acts as one unit.
Homogeneous
The effect of a moving load upon a stationary structure.
Impact load
A truss incorporating a single compression member; it is inverted because the compression member extends downward.
Inverted king post truss
A beam.
Joist
A unit for measuring the energy release rate of fire.
Kilowatt (KW)
A wall typically found in the top floor of a wood frame home with a peaked roof. This short wall squares off the triangular area at the edge of the room where the sloping roof meets the floor.
Knee wall
A force that acts on a structure from a horizontal direction, such as wind or seismic forces.
Lateral impact load
A wood board typically attached to a wall’s studs that is used to support wood joists.
Ledger board
The horizontal beam that forms the upper structural member of an opening for a window or door and supports part of the structure above it.
Lintel
The weight of the buildings contents.
Live load
A very large structure.
Megastructure
A structural system that utilizes special moment connections between columns and beams to resist rotation due to lateral loads such as earthquakes and wind.
Moment frame
A construction technique in which all successive poured concrete castings are joined together so that the structure seems to be like one piece of stone.
Monolithic concrete
When any change is to be made in the foundation of an existing wall, the wall must be supported. Often holes are cut through the wall, and so called __ __ are inserted and supported on both sides.
Needle beams
The line along which the length of the beam does not change.
Neutral axis
The connection points joining ties, struts, and chords in a truss.
Panel points
Non load bearing enclosing wall on framed buildings.
Panel wall (curtain wall)
A non load bearing wall that subdivides spaces within any story of a building or room.
Partition wall
A load bearing wall that is common to two structures.
Party wall
A masonry column projecting from one or both faces of the wall in which it is located.
Pilaster
Design based on connections that redirect overloads to other sections of the building.
Plastic design
Heavy riveting of girders to columns from the top to the bottom of the frame.
Portal bracing
A truss with two compression member.
Queen post truss
Diagonal bracing columns
Rakers
The response in structures to the imposed loads, which are generally developed at the supports.
Reaction
A load that is applied intermittently.
Repeated load
A water soluble mixture used in the past as mortar, when water is applied, the mortar can be washed away from the wall.
Sand lime mortar
A type of floor in which floor girders are set on anchor boxes in walls and caps attached to columns.
Self releasing floor
Another term for dead load
Self weight
A wall that counteracts the effects of lateral loads such as wind and earthquakes.
Shear wall
Forces occurring within a building member when opposing forces pull the member in opposite directions.
Shear
A beam supported at two points near its end.
Simple beam
A three dimensional pyramid like truss
Spaceframe
A girder that ties wall columns together in a framed building
Spandrel girder
An open web design used for the support of floors and roofs.
Steel joist
The capacity of a member or framework to resist imposed loads without excessive deflection.
Stiffness
The actual percentage of elongation (deformation) when a material is stressed. It is measured in fractions of an inch of deformation per inch of original length of the material.
Strain
Force per unit area that produces a deformation.
Stress
A masonry unit laid horizontally with its length in the direction of the face of the wall.
Stretcher
A bracing Column.
Strut
A simple beam, with one or both ends suspended on a tension member such as a chain, cable, or rod.
Suspended beam
A hanging load supported from above.
Suspended load
A pulling or stretching force in line with the axis of the body; the opposite of compression.
Tension
The tensile connecting members of a truss web.
Tie
A rod in tension; used to hold parts of a structure together.
Tie rod
The measurable turning force applied to a structural member.
Torque
A force tending to twist a structural member.
Torsion
A beam that typically carries a load around a large opening or over an area in order to avoid intervening columns.
Transfer beam
The manner in which a load is spread from the point of application to the ground.
Transmission
Externally braced structure.
Tube construction
The highest load that a member or structure can sustain before failure occurs.
Ultimate strength
A rectangular truss with very rigid corner bracing.
Vierendeel truss
A wedge shaped block whose converging sides radiate from a center, forming an element of an arch or vaulted ceiling.
Voussoir
The group of struts, ties, and panel points in a truss.
Web
Cast in place concrete that unites the rods projecting from the precast sections.
Wet joint
A single continuous vertical wall of masonry units (one masonry unit in thickness).
Wythe
