CNST 251 Chapter 4
In a simple three member truss consisting of two rafters and a tie each member is in
Tension
The unit of modules of elasticity is
all of the above
The material in an arch is primarily in
compression
A 20 ft high column shortens by .6 in under a load. What is the resulting strain in the column
.0025
Which gives greater warning before failure?
Ductile material
In most materials the safety margin for compressive stress and bending stress is the same
False
A rectangular column measuring 12 in X 12 in in cross section carries a load of 18 kps. What is the stress in the column?
None of the above
In a typical stress-strain diagram of a material, the stress is generally plotted along the vertical axis
True
The bending stress along the neutral axis of a beam are
Zero
When a cable or rope is compressed by a force, what is the compressive stress in it?
Zero
Concrete is
an elastic material
Low-carbon (mild) steel is
an elastic-plastic material
The horizontal blocking in wood studs helps prevent
buckling of studs
The test specimen used for determining the compressive strength of concrete in the US is a
cylinder measuring 6 in in diameter X 12 in high
In a steel column that rests on a concrete footing the area of the bearing plate used is generally
greater than the cross-sectional area of the column
The stirrups in a reinforced concrete beam are used to
increase the strength of the beam in shear
the allowable stress in a material is generally
less than its ultimate stress
In relation to its compressive strength the tensile strength of concrete is
much lower
What is the yield stress of grade 60 reinforcing steel?
none of the above
The primary purpose of ties in a reinforced concrete column is to
prevent the buckling of vertical reinforcement in the column
Modulus of Elasticity refers to how
stiff a material is
When we determine the strength of concrete using the test specimens, we determine the concrete's
ultimate compressive stress
A material that is weak in tension is
weak in bending
A material that is weak in tension is
weak in shear
The bearing strength of a material is closely related to its
Compressive Strength
Which of the following beam cross sections is structurally more efficient in bonding
I-section
The primary purpose of longitudinal steel bars in a reinforced concrete beam is to overcome the weakness of concrete in tension
True
The stress-strain diagram of mild steel is nearly a straight line up to the yield point
True
Which of the following beam cross sections is structurally more efficient in bending
Tubular section
In a suspension bridge which member is in compression
support pylon
