Wood privacy fence behind modular block wall

[jagti]

Can any one share a software or spreadsheet on how to calculate horizontal thrust due to wind loading from wood privacy fence offset behind wall for various heights.

thread255-242873

Thanks

 

[RFreund]

I will post a sketch of this latter that should clear this up.

I usually check overall overturning and sliding - applying the loads directly to the wall as if it all acts together. I Assume the load from the post foundation distributes at a 45 degree through the soil (plan view) to the back of the wall and use this length as my tributary length.

Also I check local forces for which basically project the forces only the height of wall that is effected.

EIT

 

[RFreund]

Also if this is a modular wall check this out from allan block. They will send you the mathcad file upon request.

http://www.allanblock.com/RetainingWalls/Newsletter/Engineer/Issue7/AB_Tech_Nwltr_Issue7.pdf

EIT

 

[jagti]

Thanks Rfreund

i will check out with them.

 

[RFreund]

Attached is a calc for load on segmental wall. It is not slightly "liberal" as I try to account for all factors that will help resist sliding and overturning. There is essentially 3 parts.

There are 2 types of walls: Walls that are taller than the foundation and walls that are shorter than the foundation (short walls).

For walls taller than the foundation I consider 2 parts:
Part 1 overall stability. Just add the force on the fence or rail to the your overall sliding and OT calcs.

Part 2 is local stability. Here I use the weight of the units, geogrid, and passive soil between units. However I do not use the weight of the foundation, I am considering using the weight of the foundation and removing the passive soil between units. I distribute the force from the foundation at a 45degree in plane view to the back of the wall and also vertically down through the wall for the height of the foundation.
If you go through the calc let me know your questions/comments.

Short wall calc uses same factors as Local stability but also includes passive soil below retaining wall.
Thanks

EIT