This Architectural drawings is section of Typical RFT details For flat slabs with depth change. As per ACI -The drop thickness should not be less than 100mm or (Thickness of slab)/4. While calculating span by depth ratio, longer span is used. The thickness of slab should not be less than 125mm. Critical section for shear in case of flat slabs is at a distance of d/2 from the periphery of the column/the capital / the drop panel, where d is the effective depth. Effective depth of beam is calculated over all deep of beam minus effective cover of beam. Now discuss about what is effective cover. Effective cover is distance between centroid of tension Steel to bottom extreme face of concrete tension fibre where maximum tension is present. For more information download the drawing file.
