Select the number and size of reinforcing bars required to resist a total factored moment of 180 ft. kips for a rectangular section with b = 12 in., d = 19.5 in., h = 24 in., f'c = 4 ksi, and fy = 60 ksi.
Check for minimum reinforcement requirement.
Use the three methods covered in class:
1. Solve the quadratic equation in As
2. Use the approximate lever arm (d - a/2) method
3. Use the design chart for R for grade 60 reinforcement