Chapter 4
A 20-ft \- high column shortens by 0.6 in. under a load. what is the resulting strain in the column?
0.0025
A rectangular column measuring 12 in. X 12 in. in cross section carries a load of 18 kips. what is the stress in the column
125 psi
What is the yield stress of grade 60 reinforcing steel?
60,000 lb
The Material in an Arch is primarily in
Compression
The test specimen used for determining the compressive strength of concrete in the United States is a
Cylinder measuring 6 in. in diameter X 12 in. high
In a simple three-member truss consisting of two rafters and a tie, each member is in
Either tension or compression
In most materials, the safety margin for compressive stress and bending is the same
False
Which of the following beam cross sections is structurally more efficient in bending?
I-Section
In a suspension bridge, which member(s) is (are) in compression?
Support Pylons
In a typical stress-strain diagram ofa material, the stress is generally plotted along the verticle axis.
True
The primary purpose of longitudinal steel bats 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 a yiled point.
True
Which of the following beam cross sections is structurally more efficient in bending?
Tubular section
When a cable or rope is compressed by a force, what is the compressive stress in it?
Zero
Which gives greater warning before failure?
a ductile material
Concrete is
an elastic material
Low-Carbon (mild) steel is
an elastic-plastic material.
The horizontal blocking in a wood studs helps prevent
buckling of studs
The bearing strength of a material is closely related to its
compressive strength
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
The primary purpose of ties in a reinforced concrete column is to
prevent the buckling of verticle reinforcement in the column
The units of modulus of elasticity are
psi, Pa, ksi, GPa
Modulus of elasticity refers to how
stiff a material is
When we determine the strength of concrete using the test specimens, we determine the concretes
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 bending stresses along the neutral axis of a beam are
zero