Cantilevered Masonry Shear Wall

[Day_Reddy]

Hi Guys,

I am trying to design the shear walls for a small(30' x 20') square masonry structure, the total ht. of the structure is 14' but my masonry wall is only upto 10' and 4' of HSS 4x4 columns on top of the masonry wall. So I have cantilevered masonry wall with cantilevered columns on top of it.
I know when it is a single story simply supported wall half the wind load is transferred to the roof and the other half is transferred to the footings. But in this case do I consider the full ht. (i.e. 14') since i have a cantilevered wall and a cantilevered column. Or do the same principles apply and only half the ht. of the wall and full ht. of the column needs to be considered(full ht of column so as to follow the load path from column to wall), therefore 5' of wall + 4' of column = 9' as my ht for wind loads.

Thanks a lot,
Day

 

[Celt83]

is this your condition:

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[Day_Reddy]

Celt83, yes this is my condition.

 

[Celt83]

if you are checking as the main wind force resisting system and have exterior walls that go from ground to roof and no other floors in between and the exterior walls are correctly attached at each end to provide a proper load path then yes the wind pressure loads the exterior wall like a simply supported beam and half the pressure goes to the roof diaphragm. The roof diaphragm then distributes the load to each lateral resisting element shear wall, frame, cant. column, etc. that is properly attached to it based on flexible, rigid, or semi-rigid principles.

Open Source Structural Applications:

https://github.com/buddyd16/Structural-Engineering

 

[Day_Reddy]

Thank you Cel83.

 

[gte447f]

Celt83, I am late to the party here, and I may be misinterpreting your reply , but I do not think there is any mechanism for wind loads on the masonry portion of the wall to get up to the diaphragm, because the wall does not "span" from foundation to diaphragm, like say in a the case of a wood stud wall or full height masonry wall. Due to this discontinuity at the top of the masonry, I think what you have is a situation where the windward and leeward masonry walls will be cantilevered walls loaded out of plane with the full wind load from foundation to top of wall plus half of the wind load on steel portion above the wall, with the end walls (parallel to the wind load) loaded at the top with the reactions from the diaphragm and steel frame which is only loaded by half of the wind load from the top of the masonry wall to the top of the diaphragm. Alternatively, the top of the masonry walls could be braced up to the diaphragm or the masonry walls could be made to span horizontally to the end walls as shear walls.