BCE Reinforced Concrete Design

Question 1

In the ACI 318 strength design method, which load combination is used for dead load (D) and live load (L)?

Accepted Answer

U = 1.2D + 1.6L

Answer

U = 1.0D + 1.0L

Answer

U = 1.4D + 1.7L

Answer

U = 1.5D + 1.5L

Question 2

The strength reduction factor φ for tension-controlled beams in ACI 318 is:

Accepted Answer

0.90

Answer

0.65

Answer

0.75

Answer

1.00

Question 3

What does the balanced reinforcement ratio (ρb) represent in beam design?

Accepted Answer

The steel ratio at which concrete and steel simultaneously reach their limiting strains

Answer

The minimum steel ratio to prevent shrinkage cracking

Answer

The maximum steel ratio allowed by ACI

Answer

The ratio at which the beam has equal top and bottom steel

Question 4

For a simply supported rectangular beam, the location of maximum bending moment is at:

Accepted Answer

Midspan (for uniform load)

Answer

The supports

Answer

The quarter points

Answer

The third points

Question 5

Which mode of shear failure in a reinforced concrete beam is prevented by stirrups?

Accepted Answer

Diagonal tension cracking leading to shear failure

Answer

Flexural compression failure

Answer

Bond splitting failure

Answer

Punching shear failure

Question 6

The minimum flexural reinforcement (ρmin) requirement in ACI 318 beams is intended to:

Accepted Answer

Ensure the beam does not fail below the cracking moment

Answer

Prevent excessive deflection under service loads

Answer

Limit crack widths at service loads

Answer

Provide fire resistance to the section