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List the five steps to a successful tilt-up project. -
Answer-1. Design
2. Planning
3. Construction
4. Erection
5. Creating Finishes
Select three disadvantages of tilt-up construction -
Answer-available space to cast panels
weight of panels on certain soils
availability of lifting equipment
temporary bracing during construction
Define tilt-up. -
Answer-Tilt up concrete is the technique of site casting concrete wall panels on a
horizontal surface and then lifting or tilting them into place.
Who is known as the father of tilt-up? -
Answer-Robert Aiken
Cold weather is defined as a period when the average daily temperature <5ºC
(40ºF) for 3 successive days and the temperature stays <10ºC (50ºF) for more than
½ of any 24 hour period. -
Answer-True
Concrete will freeze if the temperature falls below -4ºC (25ºF). -
Answer-True
What temperature range within the concrete (from the surface to the center)
should be maintained to avoid cracking? -
Answer-35ºF
Recommended concrete temperature at the time of placement of a concrete
element 10-inches in thickness is . -
Answer-55ºF
Concrete should be placed at the lowest practical slump. -
Answer-True
What are F-Numbers (FF and FL)? -
Answer-FF = Flatness : controls local surface bumpiness by limiting the magnitude of
successive 1 ft. slope changes.
FL = Levelness : limits differences in departures from design grade over
,distances of 10 ft. (measure of floor pitch)
F numbers are a standard of specification and measurement of the flatness and
levelness of concrete floors.
, What was wrong with the old "straightedge" specs? -
Answer-They were unrealistic, unscientific, and not repeatable to use. There was a
disagreement as to what they meant.
How are F-Numbers better than the straight edge method? -
Answer-Using F-numbers are better than the straight edge method because they are
easier to identify and manage the floors features for it to qualify as good.
What F-Number approximately equals 1/8th inch in 10 feet? -
Answer-FF50 is about equal to 1/8" for 10'
What is difficult about meeting an FF 50? -
Answer-Meeting an FF 50 of flatness is considered very flat or almost super flat meaning
1/8" needs to be met every 10'
How are F-numbers measured? -
Answer-Flatness is measured by the difference in slope over 2' and levelness is
measured by the difference in elevation by more than 10'
What is a Superflat floor? -
Answer-Specified overall flatness = 60 Specified overall levelness = 40
What FF and FL number would you recommend for a tilt-up project (remember the
slab- on-grade is your forming surface for your panels)? -
Answer-I would say either flat or very flat due to these slabs will be standing upright
supporting the structure. Therefore they need to be square and plumb. Additionally they
are the finishes on the outside as well so everything needs to look straight and flat.
grade -
Answer-refers to a surface
sand bed -
Answer-a casting surface intended to set larger aggregate or stones in a random pattern
resulting in uneven surfaces that would not otherwise be effective on a solid concrete
slab
slab-on-grade -
Answer-a concrete slab cast on the ground surface
subgrade -
Answer-the surface below a slab or below a base
base -
Answer-a granular material placed directly below the slab
reinforced slab -
Answer-a concrete slab containing either WWF, reinforcing bars, or fiber
How is the subgrade modulus determined? -
Answer-It is determined by the soils engineer after performing a test at the site.