A reinforced concrete water tank is to be constructed to retain full water depth of 4.5 m as shown in Figure Q.5. The cantilever wall section has uniform thickness of 500 mm. Design information is as follows: 500 mm thk. cantilever wall 5.0 m overall height Base slab of 500 mm thk. 15 m x 50 m base area Figure Q.5 Unit weight of water, w = 10 kN/m³ Nominal cover, c = 50 mm Grade 40 concrete High yield steel with fy 500 N/mm² Modulus of steel bar, Es = 200 kN/mm² Short term modulus of concrete, Ec = 25 kN/mm² Long term modulus of concrete due to creep effect =12.5 kN/mm² Vertical main bars (inner layer): T20-150 mm c/c each face Horizontal distribution bars (outmost layer): T12-250 mm c/c each face Assume the design crack width is 0.2 mm. (a) Show that the service moment on the cantilever wall under lateral water pressure is to be 152 kNm/m. (2 marks) (b) Check the adequacy of the water tank against flexural crack width under serviceability limit state (SLS). (17 marks)