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 9 — Piers, Columns, and Bent-Cap Design (15 questions)
15 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
Gross area A_g for D = 42-in pier (in²).
in²Circular pier
- Q2
Steel area for ρ = 2% and A_g = 1385 in² (in²).
in² - Q3
Nominal P_n for f′_c = 5, f_y = 60, A_g = 1385, A_st = 27.7 (kip).
kip - Q4
Design axial P_r (tied column), from P_n = 7430 kip.
kip - Q5AASHTO caps design axial for a spirally reinforced column at what fraction of P_n?
- Q6
Slenderness kL_u/r for k = 1.2, L_u = 28 ft, r = 12 in (in-consistent).
- - Q7Slenderness threshold above which moment magnification is required (sway column, AASHTO §5.6.4.3):
- Q8
Spiral ρ_s,min: A_g = 1385, A_c = 1075 (core = 37-in), f′_c = 5, f_yh = 60 ksi.
- - Q9
Required spiral pitch for #4 bar (A_sp = 0.20 in²), D_core = 37 in, ρ_s = 0.0108 (in).
in - Q10Radius of gyration for a solid circular section of diameter D:
- Q11
Approximate AASHTO barge crush force with DWT = 4000 tons, V = 7 ft/s. Use .
kip - Q12
Overturning moment about base if barge force acts 10 ft above base and equals 1800 kip (k-ft).
k-ft - Q13
Wind base shear on pier: exposed area 500 ft², V = 115 mph. Use P = 0.00256·V² (psf), F = P·A/1000.
kip - Q14Load factor γ_CV for vessel collision at Extreme Event II per AASHTO Table 3.4.1-1:
- Q15
Moment magnifier δ_ns for C_m = 0.85, P_u = 1200 kip, P_c = 9000 kip.
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