The AASHTO tables will cover this if you know the axle configuration and curb weight of the vehicle. You can get that from the manufacturer. You can estimate the payload at the maximum capacity of the truck.
The tables cover single, tandem and tridem axle configurations. If articulated, the truck will usually have a single front axle on the tractor and a tandem rear axle. The trailer will usually have a tandem axle, so you will have a single axle and two tandems. If not articulated, usually a single axle and one tandem or one tridem.