Problem #1: Determine the flexural capacity, ΦMn for the singly reinforced rectangular beams having the following properties. Use strength reduction factors from ACI Code. Use beam 1 as a reference, identify the most effective way to increase the flexural capacity of a reinforced concrete beam and discuss.
| Beam No. |
b (in.) |
d (in.) |
Bars |
f'c (psi) |
fy (psi) |
| 1 |
12 |
22 |
3 No. 7 |
4,000 |
60,000 |
| 2 |
12 |
22 |
2 No. 9 plus 1 No. 8 |
4,000 |
60,000 |
| 3 |
12 |
22 |
3 No. 7 |
4,000 |
80,000 |
| 4 |
12 |
22 |
3 No. 7 |
6,000 |
60,000 |
| 5 |
12 |
33 |
3 No. 7 |
4,000 |
60,000 |
Problem #2: Determine whether the beam's section shown satisfies ACI code requirements and calculate its design moment capacity.
f'c = 4000 psi and fy = 60000 psi,
Problem #3: Figure 1 shows a floor plan consisting of a one-way slab spanning between beams on grid lines A, B, C, and D. The beams are supported by columns at the intersections of the grid lines. The slab supports a service dead and live load of 100 psf and 75 psf, respectively.
a) Determine the effective flange width for the continuous beam along grid line B at mid-span between grid lines 1 and 2. Assume hf = 5 in.
b) Determine the effective flange width for the continuous beam along grid line B at the column support B2. Assume hf = 5 in.
Problem #4: Determine whether the beam's section shown satisfies ACI code requirements and calculate its design moment capacity. As = 6 #9
f'c = 4000 psi, fy = 60000 psi, and Es = 29000 ksi
