Chapter 12 - Fire-Resistive Construction Flashcards
Fire resistive Construction is considered to be the best because of what two reasons
It doesn’t contribute fuel to a fire and is the most resistant to collapse
Concrete after mixed sets but it what
Continues to cure indefinitely
What retards the curing of concrete
Low temperatures
Concrete is weak in what type of strength
Tensile strength
Concrete has what type of shear resistance
Poor
Most types of concrete require how many days to obtain full strength
28 days
What are the two basic types of concrete construction
Cast and place
Precast
Composite construction describes buildings in which
Different load-bearing materials are used in different areas
The common cinder block is what type of concrete
Precast
What is added to concrete to resist spalling
Polypropylene microfibers
What is the chief virtue of concrete
High compressive strength and low cost
Concrete beams have zero strength of what
Tensile
In a cantilever beam the tension is where
Top of the beam
In a continuous beam supported at more than two points tension occurs in the top of the beam where
The area over the tops of the columns
In a continuous being supported at more than two points tension occurs in the bottom of the beam where
Between the two columns
Vertical reinforcing bars designed to prevent cracking under shear stress
Stirrups
Steel has how many times the compressive strength of concrete
15
Autoclave aerated concrete is what weight compared to traditional concrete
1/4
Many concrete floors are designed as what type of beam
Continuous
Concrete floors and what type of buildings may be only load-bearing and may not contribute to the building’s structural stability
Precast pinned concrete
Prestressing concrete helps with what type of load
Tensile
A major advantage of post tensioning is that floors can be what
Thinner
What is the general limit of masonry reinforced buildings
Six stories
Interior and exterior walls are equally load-bearing in what type of construction
Reinforced masonry
Shores, formwork and lateral bracing
False work
What percentage of the cost of the concrete structure is formwork
60%
The setting of concrete is dependent on what
Temperature
Concrete port at 50° F will develop how much more pressure than at 70° F
1/3
The length of time for concrete to cure depends on what two things
The type of cement used and the temperature during the curing period
What is a indication that concrete is not yet up to full strength
The presence of reassuring
What resistance of post-tension slabs is poor
Shear resistance
Precast concrete buildings under construction are unstable until
All connections are completed
What might be the most dangerous hazard for type I buildings under construction
Heating most commonly LPG
Steal that has been fireproofed is also known as
Protected steel
What are the two types of individual fireproofing
In casement and spraying
What type of fireproofing does not protect individual members
Membrane
The addition of what can significantly affect the fire performance of an assembly
Added insulation that’s not part of the specifications
What is the most permanent fireproofing
Concrete
What is the most common encasement method for columns
Gypsum board
What is one of the fire protection advantages of concrete construction
Wax inherent voids
If a building is fire resistive it’s presumed that the floor will act as what
A barrier to the extension of fire
Most imitation concrete panels are made of a
Steel framework with asbestos millboard
What two purposes does the concrete and fire resistive Construction serve
Resist compressive stresses
Protects The tensile strength of the steel from fire
All areas were spoiling has reached the reinforcing steel should be what
Shored
Normal strength concrete loses about 25% of its compressive strength at what temperature
575° F
Normal strength concrete loses about 75% of its compressive strength at what temperature
11, 007° F
When a wall formwork burst it usually goes out where
At the bottom
Where will most victims be in a collapse of false work
On top of the false work
All cutting into what type of concrete floor is unsafe
Post tensions
Concrete structures represent a what compared to other structures
Massive heat sink
What are the two basic types of fire resistive construction
Reinforced concrete
Structural steel
Was serious fires in fire resistive buildings where is the collapse danger lie
Concrete
In steel skeleton construction the underside of each floor is what
Light gauge corrugated steel sheets
