I think you're fine, but have them sign a waiver just in case!

For the record, I'm voting option#3.

I'd also keep the pins close to the walls, maybe spread out (4 each wall) as you mentioned.

Pics, or it never happened

You will be finnee , just serve the guests salad

2 x 10's @ 16" oc. can span 16'.
You are fine.

It depends...how fat are your friends?

My gut feeling is you'll be fine. Loading makes a big difference. If the games are close to the wall, that's obviously better than if all the games were in the middle of the room. And consider that a pin might weigh 200-250+ lbs, but it is distributed over four legs that are a ways apart. A 250 lb person puts all that weight in a small spot. And the pins will help keep the load from occupants getting too out of hand because they take up a bit of space.

Building codes are pretty conservative and try to take in to account weird loadings and situations. But you can't design for every possible scenario. If the beams have any lateral bracing, you'll be in much better shape than if there's none. The beams in my home are doubled up about every 4', and that also helps. How old is the home?

Now if you said you were having a pinball dance party with 35-40 people jumping around the games, I might give a different answer.

40 guest @ 200lbs each 4 tons of people.
8 pins @ 250lbs each 1 ton of fun. 5 tons total. Don't stand in one corner, don't get to excited and jump up and down.

You'll be fine. You have an open modern home, everyone won't be crammed in tightly and the games will be spaced out near the wall.

Mandatory follow up question : JJPs or 2017 Sterns?

I count 38 people, and see 1 pinball machine inside.

Should be ok, im not a structural engineer, but i did stay at a holiday inn express last night.

Buy a couple of 2x10’s and double up a few of the existing beams or even a few beams vertically screwed in temporarily.

you are good, that is roughly around 10,000 lbs. A well built room can hold 50lbs per sq foot. So. looks like your room can support around 18,000 lbs.

If this was outdoors on a porch you would be at risk. There was a fatal instance in Chicago a few years ago where a 3rd floor porch had not been rebuilt to code and guests at a party overloaded and collapsed the porch. But indoors in a modern home you will be OK.

Like I said in my post, it is also very important how the load is distributed. Some weird loading conditions can make things fail even when you are under the design loads. And dynamic loading changes things on top of that (people dancing, jumping, etc.)

I'm not saying you won't be fine, I'm just splitting hairs. It isn't as simple as X lbs/sqft.

Disclaimer: I am not a structural engineer, nor do I play one on TV

That said, the International Building Code specifies a uniformly distributed live load design weight of 40 pounds per square foot (psf) for residential construction. I don't know the species of the wood your beams are made up of, and it does make a difference, but even Eastern Spruce (as opposed to Yellow Pine or Douglas Fir) can carry over 40 psf live load @ 15' span. Basically, your room exceeds code (as Woody76 points out, probably closer to 50 psf).

Of course, the weight isn't evenly distributed across the room. As stangbat mentions and you point out, the pins will be lined up along the walls, the best place to be for carrying weight, as much of the load will be transferred directly to the support (basement) walls below them. That leaves primarily the people which on a weight basis is well below the design loads. Without going into all the possible exceptions like concentrated load or, also as stangbat points out, a dynamic load of dancing/jumping, you will be fine. You would most likely notice any significant floor deflecting well before failure anyway. If you want, you could just see if a ball rolls to the center on those hardwood floors, or run a string along the joists below attached at the ends and mark the spot in the middle where the string is. You will see any deflection in both cases after you load the pins/under full party load.

Have a fun Tourney!

Memories...haven't done this in a while.

shear moment (resized).png

Attach half the machines to the ceiling to help reduce the load on the floor. Problem solved.

Just an engineering reference for anyone that had to endure hours of shear moment diagrams.

Haven't done V & M diagrams in a while or haven't done them correctly in a while? That one is incorrect

When doing this, be sure to invite Lionel Richie over for some dancing on the ceiling.

You said you had a basement, right?

Reminds me of Al Bundy. "One two three four, you're going to fall through the floor".

LTG : )

I haven't done them in a really long time and I didn't even really look at it, I just grabbed an image off a search.