there are reasons to reinforce the floor even if it isn't technically necessary. One thing is the loaded floor won't move when you walk by. The other is that over time a stationary load like that may cause a slight dip in the floor. A couple of ways would be to sister the beams by adding a second joist next to an existing one and attaching it to the existing, in effect, doubling it. This may be impractical if there are electrical wires running through them. The easiest way would be to put a stud wall underneath the area that will be covered by the front edge of the stand. Inexpensive and can be easily removed at a later date if necessary.
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