Background Knowledge - Strengthening Design of Reinforced Concrete with FRP - page 37

Problem 2.3
For the beam designed in Example 2.2, determine the actual moment capacity of the
doubly reinforced section ( M u ).

2#7

18"

1.0"

7#7

1.5"

10"

FIGURE 2.P.2

Problem 2.4
Design the following rectangular section as a doubly reinforced beam assuming the
strain limit of 0.005 for tension-controlled sections. M u = 60 k-ft and clear cover is
1.0 in. Assume #3 bars for stirrups and compression steel.

6 in.

f c = 5 ksi

12 in.

f y = 69 ksi

FIGURE 2.P.3

Problem 2.5
For the beam section in Problem 2.3, design the beam to resist shear such that it fails
in flexure and not shear. The beam is under its own weight in addition to a single
concentrated live load at mid span, as shown.

P

2#7

18"

16 ft

1.0"

7#7

f c = 4 ksi

1.5"

10"

f y = 60 ksi

FIGURE 2.P.4

Problem 2.6
For the beam given in Example 15.3 of the ACI440.2R-08, design the beam in shear
for the original dead and live loads. Then, check if your design provides adequate