Bracing for Masonry

[Calif]

I have a three floor building with non-bearing exterior masonry walls serving as party walls for a building. The floor heights are 16', 12' and 12' with 8-inch cmu wall along three sides of the building. ACI-530 requires lateral and vertical bracing for a ratio (l/t or h/t) of 18. I can brace at columns but my columns are seperated by 20' to 24 feet apart. This requires bracing inbetween columns at least every 12'. There is on a 2"furring inside the building for the cmu walls. Is there a way to brace the cmu in other ways knowing these constraints?

The resisant virtues of the structure that we seek depend on their form; it is through their form that they are stable, not because of an awkward accumulation of material. There is nothing more noble and elegant from an intellectual viewpoint than this: to resist through form. Eladio Dieste

 

[DaveAtkins]

I think you can ignore h/t and l/t ratios if you properly engineer the masonry.

DaveAtkins

 

[Calif]

Can you give me a reason why I could ignore it if I properly design it?

The resisant virtues of the structure that we seek depend on their form; it is through their form that they are stable, not because of an awkward accumulation of material. There is nothing more noble and elegant from an intellectual viewpoint than this: to resist through form. Eladio Dieste

 

[structuresguy]

If you put in concrete tie beams at the floor levels, you would be bracing the wall vertically at the tie beams, and horizontally you bracing would be continuous. You would then only need to design the tie beam to span horizontally from column to column, or whatever other spacing you tie it back to the structure.

 

[Calif]

Do you mean a tie beam within the cmu wall?

The resisant virtues of the structure that we seek depend on their form; it is through their form that they are stable, not because of an awkward accumulation of material. There is nothing more noble and elegant from an intellectual viewpoint than this: to resist through form. Eladio Dieste

 

[concretemasonry]

The CMU wall is a structural element and and could be built in a manner to resist and distribute loads to the remainder of the structure. Extra reinforcement to change the properties at any point can be considered as long as it is bonds into and constructed properly to distribute the loads.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[Calif]

Hi Concretemasonry

Let me ask you this. Can portions of a cmu be design to function as a column that can serve as a brace that is part of a wall? Using bond deep bond beams within the wall can serve as vertical support as long as they attach to the main structure?

The resisant virtues of the structure that we seek depend on their form; it is through their form that they are stable, not because of an awkward accumulation of material. There is nothing more noble and elegant from an intellectual viewpoint than this: to resist through form. Eladio Dieste

 

[hokie66]

Calif,
Maybe this would be clearer to you if you just think of the wall as a slab, but vertically oriented rather than horizontally. None of us would have a problem with spanning an 8" reinforced slab 16', so a wall can do the same, provided it is adequately reinforced.

 

[Calif]

Hi Hokie

I understand what they are saying, it just I think there needs to be a way to brace the wall. The concept is lost on me.

The resisant virtues of the structure that we seek depend on their form; it is through their form that they are stable, not because of an awkward accumulation of material. There is nothing more noble and elegant from an intellectual viewpoint than this: to resist through form. Eladio Dieste

 

[DaveAtkins]

Are you looking at the h/t and l/t ratios in Table 5.5.1?

Those are empirical requirements that can be ignored if you properly engineer the masonry. Design the masonry for the 16' floor to floor height.

DaveAtkins