Construction Methods & Materials Ch. 3-5
When a cable or rope is compressed by a force, what is the compressive stress in it?
0
The design wind speed for a location is the peak
3-s gust speed
The unit of modulus of elasticity is
psi ksi Pa GPa
15. Concrete is
an elastic material
The U-value and R-value of an assembly are related to each other by which relationship?
(U)(R) = 1.0
The R-value of a single glass sheet, without considering the film resistances, is approximately
0
The emissivity of a material lies between
0 &1
A 20-ft-high column shortens by 0.6 in. under a load. What is the resulting strain in the column?
0.0025
The R-value of a building assembly is influenced by the inside and outside air films. The sum of the R-value of these two films (Rsi + Rso) is approximately equal to
1.0
The R-value of a single glass sheet, including the film resistances, is approximately
1.0
For most of the US, the design wind speed of an average-risk building is
115 mph
Which gives greater warning before failure?
A ductile material
Low-carbon (mild) steel is
An elastic-plastic material
Which of the following steel stud wall assemblies gives a higher overall R-value? In both assemblies, the total amount of insulation is R-15
Assembly A has an exterior insulating sheathing of R-5 and within-stud insulation of R-10
In which of the following locations is blown-in insulation most commonly used?
Attic space
The design wind speed is also referred to as the
Basic wind speed
The unit for the measure of energy in the US system of units is
Btu
The horizontal blocking in wood studs helps prevent
Buckling of studs
Apart from the climate of the location, the other factors that affect energy-conscious building design are
Building orientation & building shape Building envelope Site conditions
The bearing strength of a material is closely related to its
Compressive strength
Within a solid, the mode of heat transfer is by
Conduction
Within an air space (cavity), the mode of heat transfer is primarily by
Convection Radiation
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
Which of the following plastic foam insulation contains air within its voids?
EPS
In simple three-member truss consisting of two rafters and a tie, each members is in
Either tension or compression
With respect to wind pressure, a building site is classified in terms of
Exposures B, C, D
Which of the following insulating materials is available in the form of rigid boards?
Extruded polystyrene
ch of the following insulating materials contain HCFC has within their voids?
Extruded polystyrene Polyisocyanurate Polyurethane
An average tornado strikes a larger area on the ground than a hurricane
False
For wind blowing along one of the two major aces of a rectangular building, the leeward wall is subjected to positive (towards-the-wall) pressure
False
For wind blowing along one of the two major aces of a rectangular building, the side walls are subjected to positive (towards-the-wall) pressure
False
Which of the following insulating materials is available in the form of batts?
Fiberglass
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 design snow load on a roof is a function of
Ground snow load of the location Roof slope Wind exposure classification of the site (all of the above)
Which of the following materials has the smallest value of emissivity?
Highly polished metal
Which of the following beam cross sections is structurally more efficient in bending?
I-section
The stirrups in a reinforced concrete beam are used to
Increase the strength of the beam in shear
The concept of aged R-value is applicable to
Insulating materials that contain HCFC gas
IECC is an acronym for
International Energy Conservation Code
On a leeward wall, the wind pressure
Is almost constant with height above the ground
The unit for the measure of energy in the SI system of units is
J
When an Al foil is used in attic spaces, it is
Laminated to inside-facing surface of roof sheathing
Aluminum foil is commonly used in building assemblies because it
Lowers heat transfer due to radiation
In relation to its compressive strength, the tensile strength of concrete is
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?
None of the above
An earthquake measuring 7.0 on the Richter scale is
None of the above
The design wind speed for an average-risk building at a location has a probability of occurrence of
None of the above
For the same thickness, which of the following materials has the highest R-value?
Polyisocyanurate
The primary purpose of ties in a reinforced concrete column is to
Prevent the buckling of vertical reinforcement in the column
The approximate R-value of an air space in a wall is
R-1
The approximate R-value of an air space in a wall with an Al foil lining is
R-2.5
A wall assembly (total area = 100 ft2) consists of 80 ft2 of opaque wall with an R-value of R-20 and a 20 ft2 of window whose R-value is R-2. The effective (overall) R-value of the entire wall assembly is approximately
R-7
The R-value of a building assembly in the SI system is referred to as the
RSI-value
The no. of mild (minor to very minor) earthquakes occurring on the earth is almost
Several thousand per yr
In a suspension bridge, which member(s) is (are) in compression?
Support pylons
According to the geologists, the earth's surface is composed of several segments that are called
Tectonic plates
Highest wind speeds are usually obtained in
Tornadoes
Everything else being the same, a building constructed of heavyweight materials is subjected to a greater earthquake load than a building constructed of lightweight materials.
True
For wind blowing along one of the two major aces of a rectangular building, the windward wall is subjected to positive (towards-the-wall) pressure
True
Like Color, emissivity is a property of the surface of the material, not of the entire body of the material.
True
When we determine the strength of concrete using the test specimens, we determine the concrete's
Ultimate compressive stress
The region of the US that is relatively more earthquake prone is the
Western US
Which of the following insulations is combustible?
XPS
The bending stresses along the neutral axis of a beam are
ZERO
the material in an arch is primarily in
compression
A building assembly with a higher U-value is thermally more insulating than one with a lower U-value
false
A wet/ moist material provides a higher R-value that if the same material is dry
false
Air is a gd thermal insulator, provided that it exists in large volumes
false
For the same thickness, which of the following materials has the smallest R-value?
gypsum
Foamed concrete is generally used as insulation in
n/a
One of the main reasons for using HCFC gas in some insulating materials is that it
n/a
The R-value of a 1-in.-thick extruded polystyrene board is 5.0. If the R-value of a 1-in.thick brick wall is 0.2, how thick should the brick wall be to equal the R-value of 1-in-thick extruded polystyrene?
n/a
The R-value of a 2-in.-thikc material is 4.0. wt si the R-value of the same material if its thickness is 1 in.?
n/a
Wt is the yield stress of greade 60 reinforcing steel?
n/a
Modulus of elasticity refers to how
stiff a material is
In a typical stress-strain diagram of a material, the stress is generally plotted along the vertical axis.
true
Insulating materials that contain HCFC gas within their cells have a higher R-value than those contain air within their cells
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
The units of measurement of U-value and U-factor are the same
true
The use of Al foil in attics is more useful in warm climates than in cold climates
true
Which of the following beam cross sections is structurally more efficient in bending?
tubular section
A material that is weak in tension is
weak in bending
A material that is weak in tension is
weak in shear
