Masonry Pilaster Design

I was wondering if someone could help me out or point me in the right direction. I am designing a 30'-0" tall cmu masonry wall with 32"x16" pilasters at 16'-0" o.c. The code that I am using is the IBC 2009. The building is a Rec Center with dimension of 80'-0"x50'-0". The glulam girders are spaced at 16'-0" and rest directly on the pilasters. There is only 2'-8" of wall solid wall on each side of the pilasters until openings are present (Windows and doors). The wind speed is not very high, only around 20 psf on the wall. Seismic forces are very low also where this building is going.

I read the NCMA TEK manual (wind loading) and you check the wall to span horizontally between the pilasters then design the pilasters for the plf. But what about fixity of the pilaster and wall? The Tek manual goes into a combination of different ways to resit the load. In my case I have a flexible diaphragm typical continuous footing and would consider myself pin-pin in the out-of-plane direction.

Your looking at 20psf *16'-0" = 320 plf (vertical) on the pilasters. Then of course you have like 35k axial load. That will give us final reactions of 40 downward and 5.3k out of plane (pin-pin). So, then the wall will have horizontal joint reinforcing to transfer loads to pilasters (designed out-of plane horizontally pin-pin). Which worked out to be #4 @16" o.c. And this building will be all fully grouted.

However, should I introduce either bond beams or tie beams at the mid-height and the top of the wall. What is the difference between a bond beam and tie beam anyway? That way the reinforcement can fit in the bond beams. So the new load path in the out-of-plane direction would be vertical span of the wall to the tie beams to the masonry pilasters as point loads. But what about the in-plane direction?

Have we completely eliminated the shearwalls all together? Or do they still resist some of the load. Are we officially counting on the pilaster to take all the load? So, Fixed at the bottom and free at the top? Or with the flexible diaphragm fixed at the bottom-pin at the top.

What I am seeing is the tie beams connected to the pilasters acting as a moment frame not shearwalls. The walls in between are strictly for components and cladding. Therefore, in seismic design what is the resisting system? Are we still looking at special sherawalls or is it now a moment frame system.

Let me know what you guys think, thanks I appreciate the help.

-Jake

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