False
According to building codes, plain concrete (concrete without steel reinforcement) is not permitted in new construction.
True
False
e.
... [Show More] none of the above.
The yield strength of prestressing steel is
a. 40 ksi.
b. 50 ksi.
c. 60 ksi.
d. 100 ksi.
e. none of the above.
True
The term prestressed concrete refers to both pretensioned and posttensioned concrete.
True
False
b. The term tendons includes strands.
Which of the following statements is true?
a. The term strands includes tendons.
b. The term tendons includes strands.
c. The term tendons refers to reinforcing bars that have been bent to required shapes.
d. The term strands refers to reinforcing bars that have been bent to required shapes.
e. None of the above.
b. Pretensioning is generally done at the precaster's plant and yields a precast, prestressed concrete member.
Which of the following statements is true?
a. Pretensioning is generally done at the construction site and yields a precast, prestressed concrete member.
b. Pretensioning is generally done at the precaster's plant and yields a precast, prestressed concrete member.
c. Posttensioning is generally done at the construction site and yields a precast, posttensioned concrete member.
d. Posttensioning is generally done at the precaster's plant and yields a precast, posttensioned concrete member.
a. approximately equal to the combined cost of concrete and steel.
In a typical site-cast reinforced-concrete structure, the cost of formwork and shores is
a. approximately equal to the combined cost of concrete and steel.
b. approximately 75% of the combined cost of concrete and steel.
c. approximately 50% of the combined cost of concrete and steel.
d. approximately 25% of the combined cost of concrete and steel.
e. none of the above.
e. none of the above.
Concrete shell roofs are not commonly used because
a. they require a relatively large amount of concrete per square foot of floor area.
b. they require a relatively large amount of steel reinforcement per square foot.
c. they require prestressing, which substantially raises their cost.
d. all of the above.
e. none of the above.
b. in elevated concrete slabs.
In site-cast concrete construction, shores are used
a. in ground-supported concrete slabs.
b. in elevated concrete slabs.
c. as formwork for concrete walls.
d. as formwork for concrete columns.
e. none of the above.
c. is provided through (a) or (b).
Height adjustability in shores made of dimension lumber
a. is provided through lapped members clamped together with specially made clamps.
b. is provided through a screw-based metal assembly.
c. is provided through (a) or (b).
d. is not provided.
c. steel pipes.
Scaffold-type shores are generally made from
a. dimension lumber.
b. plywood.
c. steel pipes.
d. steel plates.
e. all of the above.
d. all of the above.
High-density overlay (HDO) on form plywood
a. improves the strippability of forms.
b. allows easier cleaning of forms.
c. increases reusability of forms.
d. all of the above.
e. none of the above.
d. its strength-to-weight ratio is high, which reduces the weight of forms and shores.
Aluminum is commonly used as form and shore material because
a. it is chemically compatible with wet concrete.
b. it is an easily nailable material.
c. its strength-to-weight ratio is low, which reduces the weight of forms and shores.
d. its strength-to-weight ratio is high, which reduces the weight of forms and shores.
e. all of the above.
c. a large formwork assembly for floor and roof slabs.
The term flying form refers to
a. a large formwork assembly for floor slabs.
b. a large formwork assembly for roof slabs.
c. a large formwork assembly for floor and roof slabs.
d. a large formwork assembly for concrete walls.
e. a large formwork assembly for columns.
False
Reshoring concrete structures are necessary where excessive deflection of floor slabs or foundation settlement is anticipated on removal of shores.
True
False
a. general contractor.
The structural design of formwork design is the responsibility of the
a. general contractor.
b. structural engineer.
c. structural engineer, but the design must be approved by the building official.
d. general contractor, but the design must be approved by the structural engineer.
e. none of the above.
d. produce textured concrete surfaces.
Form liners are used to
a. ensure easy strippability of forms.
b. allow acid etching of the concrete surface after stripping the forms.
c. allow acid etching of concrete form before placing concrete.
d. produce textured concrete surfaces.
e. allow water washing of concrete after stripping the forms.
True
The primary purpose of steel reinforcement is to increase the tensile strength of concrete elements. However, steel reinforcement is also used to increase the shear strength and compressive strength of concrete elements.
True
False
e. to increase the shear strength of the beam beyond that provided by concrete.
Stirrups are used in a concrete beam
a. to increase the beam's compressive strength.
b. to provide tensile strength in the beam since concrete's tensile strength is negligible.
c. to increase the tensile strength of the beam beyond that provided by concrete.
d. to provide shear strength in the beam because concrete's shear strength is negligible.
e. to increase the shear strength of the beam beyond that provided by concrete.
a. No. 3 or No. 4 bars.
Stirrups are generally made of
a. No. 3 or No. 4 bars.
b. No. 4, No. 5, or No. 6 bars.
c. No. 6 or No. 7 bars.
d. bars of any diameter, as needed.
b. reinforcing bars are provided at the top and bottom of the beam.
A doubly reinforced beam is one in which
a. reinforcing bars are provided in bundles of two bars.
b. reinforcing bars are provided at the top and bottom of the beam.
c. reinforcing bars are provided in two layers at the bottom of the beam.
d. reinforcing bars are provided in two layers at the top of the beam.
e. none of the above.
d. where lap splicing of reinforcing bars will produce excessive congestion.
Mechanical couplers are used
a. to lap splice reinforcing bars.
b. as an economical alternative to lap splicing of reinforcing bars.
c. where the lap-splice length of reinforcing bars is excessive.
d. where lap splicing of reinforcing bars will produce excessive congestion.
e. none of the above.
e. none of the above.
Hooks are used
a. to lap splice reinforcing bars.
b. where the lap-splice length is excessive.
c. where lap splicing of bars will produce excessive congestion.
d. all of the above.
e. none of the above.
c. 90° or 180°.
Hooks in bars are produced by turning the bars through
a. 30° or 60°.
b. 45° or 90°.
c. 90° or 180°.
d. 180° or 270°.
c. 3 in.
Steel reinforcement in concrete elements that are permanently exposed to the earth, such as in footings, must have a minimum concrete cover of
a. 5 in.
b. 4 in.
c. 3 in.
d. 2 in.
e. 1 in.
e. (a) and (c).
The chairs used to support reinforcing steel bars are generally
a. plastic chairs.
b. steel-encased plastic chairs.
c. steel chairs with plastic-coated feet.
d. (a) and (b).
e. (a) and (c).
a. prevent the buckling of longitudinal column bars.
The most important reason for providing ties in a concrete column is to
a. prevent the buckling of longitudinal column bars.
b. increase the compressive strength of a column.
c. increase the shear strength of a column.
d. allow the formwork to be tied to the longitudinal bars in the column.
e. Ties are generally not provided in a concrete column.
e. Ties are generally not provided in a concrete wall.
The most important reason for providing ties in a concrete wall is to
a. prevent the buckling of longitudinal bars in the wall.
b. increase the compressive strength of the wall.
c. increase the shear strength of the wall.
d. allow the formwork to be tied to the longitudinal bars in the wall.
e. Ties are generally not provided in a concrete wall.
c. plywood, form ties, walers, and stiffbacks fastened together with clamps.
Formwork for a concrete wall generally consists of
a. plywood, form ties, and walers fastened together with duplex nails.
b. plywood, form ties, walers, and stiffbacks fastened together with duplex nails.
c. plywood, form ties, walers, and stiffbacks fastened together with clamps.
d. plywood and stiffbacks fastened together with clamps.
d. under some interior concrete slabs-on-ground.
A vapor retarder is required under
a. all concrete slabs-on-ground.
b. all exterior concrete slabs-on-ground.
c. all interior concrete slabs-on-ground.
d. under some interior concrete slabs-on-ground.
c. 3,000 psi.
The strength of concrete in a residential concrete slab-on-ground is generally
a. 1,000 psi.
b. 2,000 psi.
c. 3,000 psi.
d. 4,000 psi.
e. 5,000 psi.
True
A construction joint in a concrete slab-on-ground is required if the concrete in the slab cannot be placed in one continuous operation.
True
False
b. a single 1/2-in.-diameter, seven-wire strand.
The tendons used for prestressing a PT concrete slab-on-ground generally consist of
a. a single 1/2-in.-diameter, nine-wire strand.
b. a single 1/2-in.-diameter, seven-wire strand.
c. two-strand tendons, each strand made of seven wires.
d. three-strand tendons, each strand made of seven wires.
e. none of the above. [Show Less]