Civil Engineering PE Reinforced Concrete Design 3

Question 1

A short square tied column (16×16 in) has 8-#9 bars. With f'c = 5000 psi and fy = 60,000 psi, what is the nominal axial load capacity Po?

Accepted Answer

1,310 kips

Answer

1,180 kips

Answer

980 kips

Answer

1,450 kips

Question 2

The balanced reinforcement ratio ρb for a singly reinforced beam with f'c = 4000 psi and fy = 60,000 psi is approximately:

Accepted Answer

0.0214

Answer

0.0285

Answer

0.0180

Answer

0.0320

Question 3

For a one-way slab with a 15-ft simple span, the minimum ACI 318 thickness to avoid deflection calculations is:

Accepted Answer

8 in

Answer

6 in

Answer

7 in

Answer

9 in

Question 4

The strength reduction factor φ for shear and torsion in reinforced concrete per ACI 318-19 is:

Accepted Answer

0.75

Answer

0.90

Answer

0.85

Answer

0.70

Question 5

Torsional effects in a reinforced concrete beam can be neglected per ACI 318 when the factored torsional moment Tu is less than:

Accepted Answer

φ(√f'c/12)(Acp²/Pcp)

Answer

φ(√f'c/4)(Acp²/Pcp)

Answer

φ(√f'c)(Acp²/Pcp)

Answer

φ(0.85f'c)(Acp/Pcp)

Question 6

A beam with b = 12 in, d = 20 in, f'c = 3000 psi carries Vu = 35 kips. The concrete shear strength φVc (using simplified method, φ = 0.75) is approximately:

Accepted Answer

19.7 kips

Answer

14.8 kips

Answer

22.5 kips

Answer

29.6 kips

Question 7

When designing for combined bending and axial compression, the transition from compression-controlled to tension-controlled failure in ACI 318 occurs at a net tensile strain εt of:

Accepted Answer

0.005

Answer

0.002

Answer

0.003

Answer

0.004