CE 4020 Reinforced Concrete Design Exam 2 Latest Update 2024-2025 200 Questions and 100% Verified Correct Answers Guaranteed A+
Define shear lag in T-Beams. - CORRECT ANSWER: A concept used to account for
uneven stress distribution in members.
Describe how flexural steel (carries load) and T+S (temperature and shrinkage) steel are laid out in a concrete slab. - CORRECT ANSWER: Flexural steel: is the BOTTOM layer and runs PARALLEL to the span.
T+S steel: is the TOP layer and runs PERPENDICULAR to the span.
Describe the effects of compression steel on Mn. - CORRECT ANSWER: It does not
increase Mn significantly. Contribution to Mn can only be considered when adequate confinement is provided by transverse reinforcement (stirrups).
Describe the stress state in concrete that leads to flexural cracking. - CORRECT
ANSWER: Flexural cracking occurs where the bending moment stress is at its
maximum.
Describe the stress state in concrete that leads to shear cracking. - CORRECT
ANSWER: Shear cracking occurs where the shear stress is at its maximum.
Does compression steel greatly increase flexural capacity? - CORRECT ANSWER: No.Compression steel does not increase Mn significantly.
DOUBLY REINFORCED BEAMS - CORRECT ANSWER: DOUBLY REINFORCED
BEAMS
How do you calculate d for a slab section? - CORRECT ANSWER: d = h-cover-
diameter of the bar/2
How do you calculate your trial As for your slab section? - CORRECT ANSWER:
As,trial = Mu/0.9fy0.8h
How do you convert self-weight of a slab section to psf? - CORRECT ANSWER:
Multiply the self wt. (pcf) by the height (inches->ft.)
How do you convert the factored loads of a slab section to plf? - CORRECT ANSWER: Multiply the factored loads (1.4D, 1.2D+1.6L) by it's 1 ft. tributary width (section).
How do you determine the # of bars crossing the 45 degree shear crack (engaged in
shear) ? - CORRECT ANSWER: number of stirrups engaged in shear = d/s
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d: depth to steel centroid
s: stirrup spacing
How does compression steel ease fabrication? 2 ways. - CORRECT ANSWER: 1)
Compression steel holds stirrups.
2) Stirrups hold compression steel.
How does compression steel increase ductility? 2 ways. - CORRECT ANSWER: 1)
Reduces depth of compression block (a), thereby increasing strain in tension steel
2) More compression steel -> more strain in tension steel
How does compression steel reduce load deflections? 2 ways. - CORRECT ANSWER:
1) Increases stiffness of compression zone.
2) Acts against concrete creep in compression zones.
Recall the 4 mechanism that contribute to the concrete's shear capacity. - CORRECT ANSWER: Concrete Contribution, Vc:
1) Dowel action of the tension steel.
2) Vertical component of the aggregate interlock.
3) Vertical shear capacity of the compression zone.
Steel Contribution, Vs:
1) Vertical shear capacity of the stirrups.
SHEAR - CORRECT ANSWER: SHEAR
SLABS - CORRECT ANSWER: SLABS
T-BEAMS - CORRECT ANSWER: T-BEAMS
The RC shear capacity equations are based on the assumption that a flexural-shear
crack forms at an angle of 45 degrees from horizontal. - CORRECT ANSWER: True.
True or False: Adding compression steel is a great way of increasing flexural capacity
(Mn) of a beam. - CORRECT ANSWER: FALSE. Compression steel does not increase
Mn significantly.
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