Bc.. Flashcards
Permits the designer to cast the concrete in a wide variety of shapes
Cast in place concrete
Concretes ultimate compressive strength can be varied from
2500 to 6000 PSI
Most cast in place concrete is proportioned at ——and then mixed in a——
Central bulk plants
mixing truck
If the concrete is vibrated excessively as it is placed in the forms———— results
Segregation of the aggregate
The——— of concrete is significant to firefighters
Quality
Concrete that is of poor structural quality will behave poorly under fire conditions by
Spalling and even breaking apart
The single most important factor in determining the ultimate strength of concrete is
The water to CEMENT ratio
Concrete: if too much water has been used in the mix the final product will
Not achieve its desired strength
The presence of excess moisture in the concrete produces spralling in the concrete due to
Freezing conditions or the heat of a fire
When concrete arrives at the job site it’s quality is checked by administering a test known as
Slump test
Concrete with excessive slump will
Fail the test and may be rejected by the structural engineer
Another method of testing concrete is to make small test cylinders of a concrete batch and subject them to
Compression testing
Concrete framing systems: to provide for the transfer of loads and forces from one placement to the next the reinforcement steel will
Overlap the joints
Common cast in Place structural systems
Flat slab
slab and beam
waffle construction
Flat slab concrete frame is a simple system that consist of
Concrete slab supported by concrete columns
Flat slab concrete frames: in a building that will have heavy live loads the area around the column is reinforced with additional concrete in the form of
Drop panels or mushroom capitals
Flat slab concrete frames: the slab of concrete varies in thickness from
6-12 inches
Flat slab concrete frames: if the building will support light loads additional reinforcing is not necessary. this system is known as
Flat plate
A slab and beam frame consists of a concrete slab supported by
Concrete beams
Slab and beam framing: the framing system is———-and is best suited for———–
Extremely lightweight
buildings with light floor loads
Slab and beam framing: slabs in this type of construction can sometimes be ———- inches
As thin as 2
Slab and beam framing- sometimes referred to as
Concrete joist construction
Slab and beam framing: When the concrete beams run mainly in one direction the framing is known as
One way reinforced slab
Slab and beam concrete framing can also feature concrete beams running in 2 directions. such a system is known as
Two-way slab construction