Deck screws are not designed to resist shear like bolts and bolted joints are. That being said, most screws can hold between 75-125 pounds with more quality deck screws being able to hold above 200 pounds per screw.
Do screws have shear strength?
Shear strength is the amount of force a fastener can handle from the sides. A nail, has more elasticity than a screw. This means as forces are pushed against the sides of a nail, the nail can bend slightly to accommodate these pressures. A screw conversely has very little shear strength.
How much shear force can a wood screw hold?
In general, a screw can hold 80-100 pounds.