Chapter 2 - Concepts of Construction Flashcards
The greatest enemy of all firefighters is what?
gravity (13)
The majority of buildings are what type of construction?
non-fire-resistive (13)
4 Types of forces applied to a structural member:
Compression, Tension, Torsion, Shear (13)
Shear forces occur where?
Within the Building (13)
Shear forces are often the result of what?
Wind load (13)
What are the internal forces that resist the load called?
Stress & Strain (13)
How are dead loads attatched to buildings?
permanently (14)
Any substitute structural element that is of LESS MASS than the element previously used to carry an equivalent load is inherently what?
LESS fire resistant (14)
An office building floor must sustain a uniform load of what over the whole floor?
50 psf
An office building floor must have the ability to sustain a concentrated load of what on a specific location?
2000 lb
Largest Live and Concentrated Live Load
Sidewalks, driveways and yards subject to trucking
Uniform: 250 psf
Concentrated: 8000 lb
(18)
Water trapped in a building or on a roof is what type of load?
Live load. (19)
What is the weight of water?
8.34lb (20)
A master stream will add how many tons to a building in 1 minute?
over 4 tons (20)
What type of loads are delivered in a short time?
Impact loads (20)
What type of collapse is particular hazard in concrete frame buildings?
Progressive collapse
What type of wall is installed to resist lateral loads from wind and earthquakes
Shear Wall.
What refers to a force causing rotation of a structural member around a fixed point of connection where the force is applied some distance from the fixed point
Moment.
what type of construction are Externally braced buildings
Tube construction
If a wall is being breached and the structure is found to be stronger than normal you are probably under what
A concentrated load
All other conditions being equal a structure will sustain its greatest load when the load is
Axial
What type of load is straight and true evenly applied to the Bering structure
Axial load
What force passes through the centroid of the section under construction
Axial.
What force does not pass through the center of the section
Eccentric
What force is straight and true but is concentrated to one side of the center of the supporting wall or column
Eccentric
Wood paper and similar materials are estimated at what BTU/lb
8000
To measure the fire load what is multiplied
The weight of the fuel is multiplied by the caloric value and divided by the floor area
What is the primary determinant of whether a compartment will reach flash over
The heat release rate
What can carry a load that would require a compressive member of much greater size
Slender tensile member
What is steel’s safety factor
2
What represents the ratio of the strength of the material just before failure to the safe working stress
Safety factor
Buildings in which two different materials carry structural loads
Composite construction
What is the oldest structural member
The beam.
What structural member transmit forces in a direction perpendicular to such forces to the reaction points
The beam
What is an ideal beam
The cable.
What can be achieved by material mass or geometry
Stiffness or reduced deflection
The load carrying capacity of a beam increases by what
The square of its depth indirect proportion to increases in width.
As the length of span of a beam increases the safe load capacity ___ in direct proportion
Decreases
A beam that carries the load on the exterior of a frame building between the top of one window and the bottom of the window above
A spandrel girder
A beam that spans an opening in a masonry wall
Lintel
Series of closely spaced beams designed to carry a particularly heavy load
Grillage
What type of beam is the typical theater marquee
Suspended beam
On a beam heavy load should be placed directly where
Over a very close to the point of support
The truss is a type of what
Beam
Tension or compression are what type of stresses
Direct
Trusses can support axial loads but are not designed to handle
Rotational moments
What may be a clue to peaked roof with usable attic space
Dormer windows
Doubling the length of a beam ____ it’s carrying capacity by half
Decreases
What type of roof presents a serious wood and metal plate trust problem
A rising roof
What is the most serious effect of rising roofs
Weakened joints that can result from shrinking wood pulling away from gusset plates
The trust is efficient because it separates
Compression and tension forces
The top court of a trust responds exactly like what structural member
A column
A structural member that transmits a compressive force along a straight path in the direction of the member
Column
A line of columns in any direction
Bent.
Columns loose strength by the square of the
Change in length
The most efficient shape for a column is one that
Distributes the material equally around the axis as far as possible from the center of the cylinder
What shape are steel beams
“I” shaped
What shape are steel columns
“H” shaped
Short squat columns
Piers
How do piers fail
Crushing
How do long, slender columns fail
Buckling (S shape)
Very long thin columns are known as
Euler’s law columns
What is a cause of column failure
The loss of bracing
What resembles a wide slender column
A wall
The greatest use of veneer walls is
Brick veneer on wood frame
What does the veneer wall depend on for stability
The underlying wall
Non-load bearing and closing wall of one story
Panel wall
Non-load bearing in closing wall more than one story
Curtain wall
Load bearing wall common to two structures
Party wall
Nonload bearing wall that subdivide areas of a floor
Partition wall
In what type of wall do the outer and inner wythes laid in courses and finished
Rubble masonry wall
When a masonry wall is under construction it acts as what type of beam?
Cantilever
When the roof is in place a masonry wall with respect to wind loads becomes what type of beam
Simple beam supported at both ends
A masonry structure built on the outside surface of the wall
Buttress
A masonry column projecting from one or both faces of the wall
Pilaster
What member is more stable the farther the material is from the center
Column
What type of buildings the roof is vital to the stability of the structure
Tilt slab concrete buildings
What combines the function of the beam and the column
Arch
The arch is under ___ it’s entire length
Compression
Arches push ___ at the base
Outward
The trust thrusts is
Straight down
When an arch is tied the thrust is
Downward
The manner in which load is spread from the point of application to the ground
Transmission
All loads are delivered to the ground through what
The foundation
Almost all foundations today are what
Concrete
What type of building the connections are strong enough to reroute forces if a member is removed
Rigid frame
The tendency of a force to rotate a member
Moment
A beam that is only bolted to a column
Shear connection
Beam and column are bolted and welded together
Moment connection
In what type of building will the collapse of a column cause the collapse of all elements supported by that column
Steel framed building
Steel heated to what temperature elongates 9.5 in per 100 ft of length
1000° F
A residential structure will usually be designed for a floor load of what PSF
30 to 40 PSF
The only time supplying a sprinkler system should be stopped is if you are what
Operating on a low pressure hydrant grid
What is known as a firefighter killer
The typical theater Marquee
The failure of a ___ Is likely to occur much more suddenly than the failure of a ___
Column
Beam
The proper way to breach a masonry wall is to open what type of hole
Triangular
The removal of what part of an arch can cause the collapse of the entire arch
Any part
