Tent staking bleachers

[port125]

We are adding cladding to the back of an existing set of open riser aluminum bleachers (School logo/ advertising). The issue we are having is that this significantly increases the surface area for the wind loading. These bleachers are on wood skids resting on the ground and consequently when checked the bleachers fail in sliding.

We would like to pin the skids to the ground with 1/2" rebar. We feel this will work to resist sliding, however we do not have a way to quantify our assumptions. Our expected loads are small ( a few hunderd pounds ).

Does anyone know of a reference / rule of thumb for pinning to the earth with a steel bar?

Thanks

 

[MiketheEngineer]

What about over turning and uplift.

Every time I analyze these things - all three generally come into play. Thats why the gods invented foundations.

Have used Jersey blocks (highway barriers) with good success - they weigh a lot and can usually be hidden in the structure.

I have used #4 rebar and driven it into ground to prevent sliding. How good - depends on the soil and how far you drive it. Also - depends on what happens if it fails. If it just means re-driving it - no big deal. If someone might get hurt - then a whole different story.

Another thought - design a quick break away to take down for the sign. If a sudden wind blows - it just tears away in a controlled fashion. After the game - roll it up or roll it down and disconnect.

All have their merits and de-merits

 

[boo1]

Adding to Mike's ideas, some banners have vented or open mesh faces to reduce the wind loading.

Entertainment Services and Technology Association (ESTA): American National Standard E-1.21-2006 and ASCE 37 include provisions for modifying wind loads for temporary structures.