Hi everyone i have to design a simple supporting structure for 200trp cooling tower ..i have considered all the loads and the loads include the water upto a depth of 0.4m on the roof..with 0.1m free board. we have provided RCC parapet wall..my doubt is whether i have to design the base that is the roof slab according to iS3370 or like a normal slb is sufficient because the water depth is 0.4m.please give the suggetions