What do you guys use for a locker room live load? It's ancillary to a gymnasium so I think 100 psf is overkill. Judging by my gyms locker room I'd go with 50 psf live + 20 psf partitions.
Nobody going to randomly drop a 280 lb barbell set in the locker room? (280 lbs / 6 square inches = ouch! 8<)
Seems like a 300 lb person would be your max load - all of that on two feet. Lockers are lightweight and spread out, but the benches? Easy to imagine a couple of three heavy-weights sitting at the same time on a bench held up by only two posts.