concrete wall reinforcement

[COEngineeer]

according to 14.3.5 vertical and horizontal reinforcement shall not be spaced farther apart than 18".

Now usually I spec #5 for basement wall. A lot of time I design it as pinned at the bottom so I need a lot of horizontal reinforcement but not whole lot vertical. Do I still need to use #5 @ 18" o.c. vertically? or can I follow aci 14.2.7? This is ACI 318 btw.

I am asking this because my boss always tell me to put it @ 16" vertical. I feel like for this particular basement wall I design, the horizontal steel will do most of the work (#5 @ 12" o.c.). Can I space the vertical only at 36" o.c.? Based on my calc, 36" o.c. vertical is plentiful. (8" thick wall, d=4).

thanks!

Never, but never question engineer's judgement

 

[DaveAtkins]

Basement walls can be designed as unreinforced, so you can use whatever spacing you want. But if you exceed the 18" spacing, you must assume the wall is unreinforced.

But I don't understand how you are designing the wall. Basement walls usually span vertically. How are you designing it to span horizontally?

DaveAtkins

 

[miecz]

If you are using reinforcing to carry the load in the horizontal direction, then you have a reinforced wall. You can't have a wall that is reinforced in one direction and unreinforced in the other. So, your maximum bar spacing is 18 inches in both directions. I would go to a #4 bar vertically.

 

[COEngineeer]

dave, I designed it like a tank.

Never, but never question engineer's judgement

 

[DaveAtkins]

Then I agree with jmiec--if it's designed as a reinforced structure, use the 18" max spacing.

DaveAtkins

 

[COEngineeer]

k.. i spaced it at 18". I still understand what so significant with 16" o.c. My boss keeps telling me to use 16" o.c. Thanks!

Never, but never question engineer's judgement

 

[miecz]

It's a good practice to use 16" O.C. vertically, as it lines up with increments of block reinforcing.