Part 8 Flashcards
What is a one way concrete slab?
A one way concrete slab is a type of slab with reinforcement only in one direction, cast integrally w parallel supporting beams
True or False: One way concrete slabs are generally used for short spans.
True
What type of loads do one way concrete slabs primarily resist?
Bending loads
What is the minimum thickness recommended for one way concrete slabs?
100mm
span/30 for floor slabs
span/36 for roof slabs
What is the typical spacing of reinforcement bars in one way concrete slabs?
100mm to 200mm
Why are one way concrete slabs not suitable for longer spans?
Due to potential deflection issues.
What is the recommended concrete mix for one way concrete slabs?
25MPa
What is the main advantage of using one way concrete slabs?
They are cost-effective and easy to construct.
What is the maximum span length recommended for one way concrete slabs?
6m
True or False: One way concrete slabs can be used in areas with heavy traffic loads.
False
What type of reinforcement is commonly used in one way concrete slabs?
Steel reinforcement
One way concrete slabs are designed as ____________ slabs.
simply supported, on two sides by beams or load bearing walls. Beams can be supported by girders or columns
True or False: One way concrete slabs are suitable for irregularly shaped structures.
False
What is the primary disadvantage of one way concrete slabs?
Limited span length capabilities.
What is the critical design aspect to consider when designing one way concrete slabs?
Reinforcement spacing and arrangement.
True or False: One way concrete slabs are suitable for heavy industrial structures.
False
What is the recommended depth of one way concrete slabs for residential construction?
100mm
What is a floor system?
Horizontal plane supporting live loads (people furnishings, movable equipment) and dead loads (weight of floor construction) - depth related to size and proportion of structural bay span + material strength. Deflection is a critical control factor. Consider mech and elec within the system. Consider sound and FRR.
What is the purpose of a vapour barrier in Canada?
To prevent moisture from entering the building envelope.
True or False: In Canada, vapour barriers are required by the building code.
True
What type of material is commonly used for vapour barriers in Canada?
Polyethylene plastic
What is the recommended placement of a vapour barrier in Canada?
On the warm side of the insulation
Fill in the blank: Vapour barriers in Canada are typically installed on the __________ side of the building envelope.
warm
What can happen if a vapour barrier is installed on the cold side of the insulation?
Moisture can get trapped and cause damage.
What is the main function of a vapour barrier in Canada?
To control the movement of moisture vapor.
What are some consequences of not installing a vapour barrier in Canada?
Mold growth, rot, and reduced energy efficiency.
Fill in the blank: Vapour barriers are designed to prevent the diffusion of __________ through the building envelope.
moisture
What are some common locations for installing vapour barriers in Canada?
Walls, ceilings, and floors
What is the recommended perm rating for a vapour barrier in Canada?
Less than 1 perm
What is the purpose of a vapour barrier in a Canadian building during the winter?
To prevent warm indoor air from condensing on cold surfaces.
What are some potential benefits of installing a vapour barrier in a Canadian building?
Improved energy efficiency, increased comfort, and reduced risk of moisture damage.
Fill in the blank: Vapour barriers are designed to be a __________ barrier to prevent moisture from entering the building envelope.
continuous
Two way slab and beam
Uniform thickness reinforced in 2 directions, cast integrally w supporting beams and columns on all 4 sides (square ish bays = most efficient). Reinforcement in column and middle strips. Subject to lower bending moments than simply supported slabs.
Two way waffle slab
2 way concrete reinforced by ribs in 2 directions - able to carry heavier loads and longer spans. At column heads, solid squares are used for additional shear strength and momentum resisting capacity. Can be cantilevered 1/3 of the main span.
Two way flat plate
Uniform thickness over columns without beams - good for apartment or hotel construction. Shear at column locations governs thickness of flat plate. Shear at column main consideration.
Two way flat plate
Uniform thickness over columns without beams - good for apartment or hotel construction. Shear at column locations governs thickness of flat plate. Shear at column main consideration.
Two way flat slab
Flat plate thickened at column supports to increase shear strength and moment resisting capacity. Can support relatively heavy loads and spans from 6-12m
Pretensioning
Stretched reinforced tendons into concrete casting - tensile tension causes slight upward curvature or camber - deflection of member under loading tends to equalize the curvature
Tensioning reinforcing tendons after concrete has set
Post tensioning
What is the span range for a 2x6
Up to 10’ (3050mm)
Span range for a 2x8
8-12’ (2440-3660”
Span range for 2x10
10-14’ (3050 - 4264mm)
Span range for 2x12
12-18’ (3660-5485)
True or false: stiffness of joist framing under stress is more important than strength
True - deeper joists spaced farther apart are more desirable for stiffness than shallow joists spaced close together
