Interior Pressure and Expansion Joint

[chriskrol]

I am calculating wind pressures acting on masonry walls and I have an expansion joint perpendicular to the wind direction. In this case the wall is experiencing only windward or leeward pressure but I am wondering if I should also account for additional interior pressure.
Thanks a lot
Kris

 

[WillisV]

Yes - Masonry walls are typically Components in Cladding and should be designed as such with the appropriate external and internal pressure coefficients acting simultaniously for the worse case forces.

 

[chriskrol]

Thanks Willis, and that's what I did for cladding but I meant the total horizontal wind pressures for MWFRS.
Thanks

 

[WillisV]

When you look at total wind pressures for MWFRS you find the force over the entire building. Internal pressures are always both acting either inwards or outwards and therefore when you sum horizontal forces they cancel out.

Windward --> | <--internal internal ---> | Leeward -->

Internal forces cancel and leave Windward + Leewards for building frame design.

 

[JAE]

You would include it if you have the perpendicular expansion joint as you describe. The internal pressure can only "cancel out" if the building is whole. With an EJ through it, the windward half would experience the external plus the internal as the internal pressure cannot be resolved across the joint.

 

[chriskrol]

Thanks JAE. It is correct what you saying

 

[WillisV]

Good point.

 

[TPNY]

I have a question, then...

In this case, on the windward wall, the internal pressure is acting in the same direction as the wind or opposite?

 

[chriskrol]

Zo40
I took it as a summ of internal+external pressures so as they act in the same direction.