A two-span continuous concrete beam is to be supported by three concrete walls spaced 30 ft on centers. A service live load of 1.5 kips/ft is to be carried in addition to the self-weight of the beam. Use pattern loading; i.e., consider two loading conditions: (1) live load on both spans and (2) live load on a single span. A constant rectangular cross section is to be used with b %d, but reinforcement is to be varied according to requirements. Find the required concrete dimensions and reinforcement at all critical sections. Allow for No.3 stirrups for shear. Use a span-to-depth ratio of 15 (L/h= 15 h%=D0.067L) as the first estimate of the depth. Adjust the depth if the reinforcement ratio is too high. Include sketches, drawn to scale, of the critical cross sections. fy 60,000 psi and f= 6000 psi. Notes: The beam is simply supported at Points A and C Find the positive moment in Span I and the negative moment at Point B. Then size the cross section based on the maximum moment from Cases I and 2 After finding the cross section then provide the area of steel for positive moment and negative moment WGDa Set Weght, Se igh Case No. 2 Maximum Case No. 1 Maximum Negative Moment at B. Positive Moment in Span 1