Ch. 4 multiple choice
Concrete is...
a- an elastic material
The material in an arch is primarily in...
a- compression
In a steel column that rests on a concrete footing, the area of the bearing plate used is generally...
a- greater than the cross- sectional area of the column
The primary purpose of ties in a reinforced concrete column is to...
a- prevent the buckling of vertical reinforcement in the column
In a typical stress-strain diagram of a material, the stress is generally plotted along the vertical axis.
a- true
The primary purpose of longitudinal steel bars in a reinforced concrete beam is to overcome the weakness of concrete in tension.
a- true
The stress-strain diagram of mild steel is nearly a straight line up to the yield point.
a- true
When we determine the strength of concrete using the test specimens, we determine the concrete's...
a- ultimate compressive stress
Which of the following beam cross sections is structurally more efficient in bending?
b- I-section
Which gives greater warning before failure?
b- a ductile material
In most materials, the safety margin for compressive stress and bending stress is the same.
b- false
The allowable stress in a material is generally...
b- less than its ultimate stress
Modulus of elasticity refers to how...
b- stiff a material is
Which of the following beam cross sections is structurally more efficient in bending?
b- tubular section
A material that is weak in tension is...
b- weak in bending
A material that is weak in tension is...
b- weak in shear
Low-carbon (mild) steel is...
c- an elastic- plastic material
The bearing strength of a material is closely related to its...
c- compressive strength
In a simple three-member truss consisting of two rafters and a tie, each member is in
c- either tension or compression
in a suspension bridge, which member(s) is (are) in compression?
c- support pylons
When a cable or rope is compressed by a force, what is the compressive stress in it?
c- zero
the bending stresses along the neutral axis of a beam are...
c- zero
A 20-ft-high column shortens by 0.6 in. under a load. What is the resulting strain in the column?
d- .0025
The horizontal blocking in a wood studs helps prevent...
d- buckling of studs
The stirrups in a reinforced concrete beam are used to...
d- increase the strength of the beam in shear
In relation to its compressive strength, the tensile strength of concrete is...
d- much lower
A rectangular column measuring 12in x 12in in cross section carries a load of 18 kips. What is the stress in the column?
d- none of the above
The unit of modulus of elasticity is...
e- all of the above
The test specimen used for determining the compressive strength of concrete in the United States is a...
e- cylinder measuring 6in. in diameter x 12in. high
What is the yield stress of grade 60 reinforcing steel?
e- none of the above
