Chapter 4
In a suspension bridge, which members are in compression?
Support pylons.
A 20 ft high column shortens by 0.6 in. under a load. What is the resulting strain on the column?
.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 A36 steel?
36 ksi.
Which gives greater warning before failure?
A ductile material
In most materials the safety margin for compressive stress and bending stress is the same.
False
Which of the following beam cross sections is structurally more efficient in bending? Rectangular (Solid) Section or I - section?
I-section
In a typical stress-strain diagram of a material the stress is generally plotted along the vertical axis.
True
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? Rectangular (Solid) Section or tubular section?
Tubular section
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 material in an arch is primarily in
compression.
The bearing strength of a material is closely related to its
compressive strength.
The test specimen used for determining the compressive strength of concrete in the U.S is a
cylinder measuring 6 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 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.
Modulus of elasticity refers to
how stiff a material is.
The stirrups in a reinforced concrete beam are used to
increase the strength of 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 vertical reinforcement in column.
The units if modulus of elasticity are
psi, ksi, Pa, GPa.
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 bending stresses 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.