It depends on how the deckis "engineered". Some could be built that are barely able to support their own weight. Others could be built strong enough to park your car on them.
It depends on the type and dimension of wood used for the joists, the spacing between joists and the length of the span.
It is not recommended to build a gazebo on a deck because the deck may not support the weight of a gazebo. Try using your deck for its intended purpose and putting some furniture out there to enjoy.
120 pounds
Depends on the structural integrity of the deck.
How long are the 2x10's, what is supporting the deck and how is the deck attached to that support. A lot of factors go into figuring load limits.
not much
The bigger, the stronger generally, and the more weight they can support. But the footers and support beams have to be sized properly also.
it can hold as much weight as it can handle
4.3 Lbs. That's based on the length/width of the deck being no more than 6". A suspension bridge will support more... Go find some string!
Yes , you can skate with a cracked deck as long as the board has enough strength to have the weight of the person on it without bending too much
14lbs. try it.
A two by four can support a load up to 400 pounds. The length of a two by four will change the weight it can support.
The cylinder will support, at neutral buoyancy, as much weight as the weight of water it could contain, less the weight of the cylinder itself.