For a four-span continuous beam with flanged section and the length of each span =5 m, the characteristic permanent load (including the self weight of the beam) Gk​= 25kN/m and the characteristic live load Qk​=10kN/m. Assume the width of flange bf=600 mm, the width of web bw=275 mm, the effective depth d for both sagging and hogging bending =500 mm,C25/30 concrete and grade 500 steel.

(a) Identify the load combinations for the maximum sagging moment (i.e., maximum mid-span moment) throughout the beam.
(b) Identify the load combinations for the maximum hogging moment at the interior supports.
(c) Determine the areas of reinforcement required to resist the maximum mid-span sagging moment.
(d) Determine the areas of reinforcement required to resist the maximum support hogging moment.