I don't think I've seen a semi w/ conventional shocks other than on the front - just like your truck should already have - on the back you'll usually find various configurations of air suspension, particularly
air cushioned walking beams for use on rough roads
shock absorbers work more to dampen the bounce of the vehicle on the chassis, where on a truck what is needed is something that keeps the wheels on the rough road - shocks won't do it w/ the giant stiff spring packs on heavier trucks
Bill
