Alright, Strength is a linear progression, as from page 222 of PHB: 10 STR lifts 200 lbs while moving, while 20 STR lifts 400 lbs while moving, etc etc. The Weight and Height of a Dwarf, from page 36, is around 4'3" to 4'9" an 160-220.
Even assuming a Sizable Dwarf, a 4'9" 220 lb being, even being broadly stocky enough to support additional weight at that moment, would have non-trivial medical problems when they approach the scales of 400lb and 540lbs.
This is beyond considering a STR 18 360lb lifting 85lb halfling being just incredulous.