Definition of Top bar and Other bar in ACI318

As per the ACI318 tables for the Development and Splice lengths in the thread, Top bar in ACI318 is defined as the bar fixed on concrete that is 300mm thick or more. Other bar is defined as any bar fixed below that thickness just above the concrete cover. So those vertical or horizontal bars in a wall or a column will only follow the Other bar lengths mentioned in the tables. This difference is because of amount of bubbles on top are muchj higher than their amount under the bottom reinforcement, causing less bond between the bar and the concrete.