Deflection for visibility

[BatMan]

Hi,
I have a 10-ft beam span under uniform loading, supporting visual screens (projection similar to monitors). Deflection is at L/1000 and I want to know if this will be visible to end users at 20~40 ft away. For non building structures without specific deflection limit, what would be typial slpe that will be bsible to others? Thank you.

 

[rapt]

Normal limit for visual deflection in buildings is L/250. At L/1000 I would doubt that you could see the deflection from this distance.

Do the screen suppliers give recommended deflection limits?

 

[BUGGAR]

I suggest a very tight deflection spec if the load vibrates.

 

[TehMightyEngineer]

As BUGGAR said, if the load is applied or removed rapidly then you will likely have a more obvious effect than if it was slowly applied and removed.

I'd go for L/800 which is what bridges are limited to in AASHTO.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[XR250]

I'd go for L/800 which is what bridges are limited to in AASHTO

What does a bridge deflection have in common with visual screens?

 

[TehMightyEngineer]

It's a structure subject to rapid loading and unloading that I imagine would scale well to the distance the OP's clients are viewing the monitors and the size of his/her 10 ft beam. Seemed like a good starting point.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com