This educational application supplements, but does not replace, the official AASHTO LRFD Bridge Design Specifications, applicable state DOT manuals, project specifications, and professional engineering judgment.
Graded quiz
Chapter 5 — Bridge Deck Analysis and Design (8 questions)
20 questions · PE-exam format · 70% to pass · attempts save to your progress record when signed in.
Work each item to the requested precision. Use the Show clue button only after an honest attempt — hints reveal the AASHTO section and setup, not the answer.
- Q1
The AASHTO §4.6.2.1 equivalent-strip method for deck slab analysis provides:
- Q2
Girder spacing S = 8 ft. Compute positive-moment equivalent strip width E+ (in) = 26.0 + 6.6·S.
in - Q3
Same S = 8 ft: compute negative-moment strip E− (in) = 48.0 + 3.0·S.
in - Q4
The AASHTO §9.7.2 empirical design method for concrete deck slabs relies on:
- Q5
Deck slab, 12-in-wide strip, d = 7.5 in, As = 0.62 in²/ft (#5 @ 6″), fy = 60 ksi, f'c = 4 ksi. Compute a = Asfy/(0.85 f'c b) (in).
inDeck slab strip — 12″ wide
- Q6
Same strip: compute φMn = φAsfy(d − a/2), φ = 0.90 (k-ft/ft).
k-ft/ftSingly-reinforced beam
- Q7
Minimum concrete deck slab thickness per §9.7.1.1 is:
- Q8
Deck DL: 8-in slab, γc = 150 pcf, 2-in FWS at 140 pcf. Compute total unit DL (psf).
psf - Q9
For deck slab design, the truck axle load applied per wheel is:
HL-93 design truck
- Q10
Deck live-load moment: axle 32 kip on strip E+ = 78.8 in, transverse span (girder spacing) S = 8 ft. Approximate positive moment per foot: M ≈ (P/E)·(S/4) with IM = 1.75. Compute using P = 32 kip (both wheels close), E in ft. Report M (k-ft/ft) — simplified.
k-ft/ft - Q11
AASHTO Table A4-1 provides:
- Q12
Deck overhang 4 ft from CL of girder to face of curb. Wheel P = 16 kip located 1 ft in from curb face (i.e., a = 3 ft from girder). Compute wheel moment (k-ft) at fascia girder.
k-ftDeck overhang — wheel load 1 ft from barrier
- Q13
Deck overhang design must consider (§13.4.1) three cases. Case 1 is:
- Q14
TL-4 barrier: transverse force Ft = 54 kip distributed over Lt = 3.5 ft, applied at height He = 32 in. Compute moment at deck (top of overhang) per foot width for 1-ft strip directly under load (k-ft/ft).
k-ft/ft - Q15
Minimum deck reinforcement per §5.10.6 (isotropic bottom reinforcement for empirical decks):
- Q16
Distribution reinforcement (secondary, bottom) as % of primary steel, for primary parallel to traffic:
- Q17
Primary reinforcement perpendicular to traffic, S = 8 ft. Compute distribution reinforcement ratio (%).
% - Q18
Concrete cover on top deck reinforcement (concrete exposed to deicing salts) per §5.10.1:
- Q19
Simple-span deck strip between girders, S = 8 ft, wDL = 0.123 klf (100 psf slab). Compute midspan positive DL moment per foot (k-ft/ft).
k-ft/ftDeck strip DL per foot
- Q20
Deck slab required area of steel: Mu = 8.5 k-ft/ft, φ = 0.9, jd ≈ 0.9d = 0.9(7.5) = 6.75 in, fy = 60 ksi. Compute As,req = Mu/(φ fy jd) in in²/ft.
in²/ft
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