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
