Park Bench Design Live Load?

[PEinc]

I can't seem to find anything on minimum design loads for fixed, wood slat, park benches. Does anyone know if there is a minimum uniform load or minimum concentrated load for bench design? I searched these forums, the internet, ASCE 7-98, and IBC with no success so far. Design load information or a reference would be appreciated.

 

[abusementpark]

You may have to use engineering judgement. I'd go with 50-60 psf and that is based off of a gut feeling.

 

[PEinc]

50-60 psf sounds like a total capacity that many benches claim to support (On bench web sites, I've seen about 400# for a small bench, about 800# or 900# for a large bench). A 200+ pound person could probably load a limited area of the bench to about 100 psf. Agree? It seems to me unlikely that the entire bench could be loaded to 100 psf. However, any one slat or a few connected slats in the bench could have a concentrated load of over 200# plus impact. It would probably be a good idea to check a concentrated load, possibly with impact, in case someone is standing or jumping on the bench. However, you can never design to bench to be indestructible. I've sent a request to my client to check with the project engineer or architect for their thoughts.

 

[SlideRuleEra]

PEinc - I had never thought about it, but when I saw your question, one seemingly reasonable analogy came to me:

Use the same criteria as stairs. From ASCE 7-02, that is a UDL of 100 PSF (for public areas) and a concentrated load of 300 pounds on an area of 4 sq. inches.

A bench is certainly not a stairway, but a lot of similarities... and someone really could step on it.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[PEinc]

Thanks. That does make sense. I'm just trying to make sure I'm not missing a bench design requirement that everyone, except me, knows. A bench can be subjected to a lot of heavy abuse.

 

[abusementpark]

I wouldn't go so far as to liken a bench to a stairway. Two people could move a piano or heavy cabinet up stairs. Nobody should be carrying anything substantial on a bench. They say that an empty room filled to capacity with people is about 50 psf. Just something to consider. Using a 100 psf is definitely a safe assumption.

 

[slickdeals]

Stadium Bleachers are designed for 60 psf, I believe and I would think that it is similar to a bench.

 

[PEinc]

Thank you. 60 psf doesn't sound like much for people standing on bleachers.

 

[slickdeals]

Just to correct myself,

Bleachers --> 100 psf
Fixed Seats --> 60 psf

 

[JAE]

Is this a bench situated next to a donut shop or a candy store? At least here in the US, there is a need to slowly increase seat live loads due to....well, very heavy people.

 

[PEinc]

It's a new bench outside a new hospital building. Therefore, it probably won't get the amount of abuse that a park or playground bench would get.

To me, it's confusing if the bleacher load of 100 psf and the fixed seat load of 60 psf are meant for design of the seats themselves or for design of the building's floor or the framing that supports the bleachers.

 

[BRGENG]

I agree with SlideRuleEra and use the Stair design criteria.

 

[PEinc]

Thank you. So I take it that there are no specific design loads just for benches?

 

[Dinosaur]

Why shave this design? I would be worried a bunch of kids would be jumping on them. If they all started breaking under this type of use, what would your client think?

 

[PEinc]

FYI, I just got back the project spec design criteria for the benches: 2 adults at 225 pounds each with a maximum deflection of 1:400, approximately 1/8" in a 4'-0" span.

Not very informative.

 

[MikeHalloran]

Think high school defensive line jumping on it...



Mike Halloran
Pembroke Pines, FL, USA