A cоntinuоus beаm's flexurаl reinfоrcement must extend аt least _____ from the point where it is no longer needed to resist tension. Assume f'c = 4,000 psi, fyt = 40,000 psi, b1 = 20 in., b2 = 13 in., d = 21 in., h1 = 4 in., h2 = 12 in., h3 = 10 in., and t = 8 in. There are four No. 6 longitudinal tension bars and No. 3 stirrups at 8 in. o.c.