Concrete and Masonry Flashcards
(27 cards)
What is the purpose of a footing in an exterior bearing wall?
To transfer building loads to the soil.
Why is excavation not taken all the way down with machinery?
To preserve undisturbed soil at the bottom for better bearing capacity.
Why are footings and foundation walls poured separately?
To simplify construction and ensure each performs its own structural role.
What is a keyway and its purpose?
A groove in the footing to prevent the foundation wall from sliding.
Where is rebar typically placed in footings?
At the top and bottom to resist bending and tension.
What does vertical rebar in foundation walls do?
Provides resistance to bending and lateral forces.
Why might rebar be placed on both the inside and outside of a foundation wall?
To resist bending in either direction depending on bracing conditions.
What is the function of welded wire fabric in a concrete slab?
To reduce cracking by reinforcing the slab.
What prevents bond between slab and foundation wall?
A bond breaker material to allow movement and prevent cracking.
What is capillary action and why is it important in concrete design?
Water moves through narrow gaps; must be controlled to prevent moisture intrusion.
What is the role of gravel under a slab?
Dissipates hydrostatic pressure and provides voids for water.
What is a vapor barrier under a slab used for?
To stop moisture from rising into the building.
What does a drain tile do?
Redirects water away from the building via gravity or a sump pump.
Why are precast elements shaped uniquely?
To match their structural role and bearing requirements.
What is a hollow core slab?
A precast slab with internal voids to reduce weight and span long distances.
What is the purpose of concrete topping on precast slabs?
To tie elements together and create a uniform floor.
What is a double T precast member used for?
Large span slabs, especially in parking garages.
What type of bond is common in structural CMU walls?
Running bond, for better load distribution.
Why are CMU cavities filled with grout?
To embed rebar and strengthen the wall structurally.
What is a bond beam in CMU construction?
A U-shaped CMU course with rebar and grout acting as a beam.
Why is rebar overlapped in CMU construction?
To ensure continuity of structural load transfer.
What is a fire cut in wood beams?
An angled cut to allow the beam to fail without pulling the wall down.
Why are beams not tightly embedded in masonry walls?
To avoid collapsing the wall during fire-induced failure.
What is a control joint in masonry?
A weakened area to control where cracks form.
