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44 Cards in this Set
- Front
- Back
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Wind lateral loads induce what on a building vs. Seismic lateral loads on a building?
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significant bending on a building where seismic induces shear at the base of the building.
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Resonance and seismic design, what can be problematic with regard to resonance?
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it occur when the force acting upon an object is in harmonic rhythm with the displaced objects period of vibration thus the vibration is amplified.
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to avoid resonance amplification how should the building be designed in response to the site?
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flexible sites should have stiff buildings and stiff sites should have flexible buildings.
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how does one achieve dampening with regard to seismic design, what are some possible strategies?
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1. shock absorbers (springs)
2. cushioning material at the foundation 3. heavy mass counter balance at the top of the building. |
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what is a spandrel?
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a wall panel located between the head of the window below to the sill of the window above.
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caryatid
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like a column but usually carved in the form of a person.
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collector (structural)
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a structural member that transfers lateral forces to another structural member.
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what can counter-act uplift forces?
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dead load
increased dead load is considered beneficial to counter act uplift forces. Also, ties used on light members. |
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what are other uplift forces that should be considered?
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frost action
hydrostatic pressure seismic action |
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wind effect, the wind-ward face of a building usually experiences positive pressure however,
the lee-ward face or sides faces usually experience what? |
negative wind pressure or suction
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regarding wind, what do flat or low sloped roofs (<9:12) experience regarding wind pressure?
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negative wind pressure or suction
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wind design?
What is the primary concern regarding wind, maximum sustained velocity or effects of gusts of wind? |
maximum sustained velocity
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what is the curve of a cabled suspension bridge with an evenly distributed load?
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parabolic curve
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What is the curve of a cable carrying only it's own weight, i.e. a power line?
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catenary curve
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what is the gradient height in rural areas?
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900 ft agl
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what is the gradient height in suburban areas?
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1200 agl
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what is the gradient in urban areas?
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1500 agl
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Basic Wind speed is measure at how high above grade.
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33' above grade
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With respect to wind, dead load is generally:
1. Considered an advantage 2. considered a disadvantage 3. considered an upward force 4. Not calculated |
considered an advantage
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With respect to seismic, dead load is generally:
1. Considered an advantage 2. considered a disadvantage 3. considered an upward force 4. Not calculated |
considered a disadvantage, it increases base shear.
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in comparison to wind loads, seismic lateral forces are applied where, different from wind loads?
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applied at the base of the building where it comes into contact with the ground.
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what loads are the most damaging to a building?
Vertical or horizontal |
Horizontal
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what is the average weight of reinforced concrete?
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144-150 pcf
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what is the average weight of fresh water?
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62.4 pcf
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what is the average weight of snow?
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8 pcf
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what is the average weight of dry clay soil?
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63 pcf
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what is the average weight of dry or wet sandy gravel?
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119 pcf
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what is the average weight of cast alluminum?
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165 pcf
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what is the average weight of steel?
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490 pcf
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asphalt shingles
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1.7 to 2.8 psf
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.5" gypsum wall board
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2 psf
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what is the average weight of 2 x 4 wood stud with gypsum wall board on both sides?
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8 psf, or 35-40 pcf
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Name three types of retaining wall failures.
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1 overturning
2 settlement 3 sliding |
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to resist failure, retaining walls are usually designed with a safety factor of x times or the ability to withstand x times their overturning moment.
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1.5 times
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What is dynamic later force analysis?
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analysis of seismic loads on your building using actual or simulated earthquake data obtained from accelerographs in existing buildings.
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When is dynamic later force analysis required?
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required in seismic zone 3 and 4
and all buildings over ten stories or having a slenderness ratio over 5 |
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what limits on aspect ratio, if any, for columns and beams by code?
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limits on unbraced length to thickness for columns
limits on span to depth ratio for beams. |
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what is the typical thickness of a gusset plate in a structural connection
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3/8 or 1/2 inch
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how should things be loaded on trusses. symmetrically or A symmetrically? Does it matter?
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Yes it does matter, symmetrically.
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truss gusset connection how many bolts are required?
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minimum of two.
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Steel trusses or Open web steel joists. What are the different kinds of trusses or designations?
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K = standard
LH = Long Span DLH = Deep Long Span |
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Equation M =
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Moment usually
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What is moment?
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bending or rotation
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Equation V =
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Shear
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