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Re: Landslide -pier tie spacing

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In a message dated 98-03-12 01:39:43 EST, you write:

<< Why you would
 require the extra ties when the capacity of the concrete is probably 10 times
 greater than the capacity of the soil so it is really impossible to generate
 enough axial load in the column to cause a concrete failure is beyond me.
 then again, I'm not a plan checker! >>

But you are S. E. and designer are you not?

I do not know what the plan checker would ask for this requirement.  He
probably has a good reason.  However, I would favor having closer ties
regardless of the fact that concrete is stronger than soil .  Most contractors
purchase the spiral ties and rebar cage directly from shop.  The relative cost
of having closer ties is insignificant.  I would not go as close at 4" spacing
on residential projects for practical reasons unless the forces are really
high and closer ties are necessary and you will have really good control over
concrete pouring operation.

Some earlies posts to this thread commented about 12 dia. piers with 4#4 bars.
I would rather provide 1#7 or #8 in the center if the site is nearly level and
the lateral forces are really small.  Of course, I tie all the piers with
grade beams.  Otherwise, a 16" dia. pier  with 4#5 is the minimum size I
specify on my projects.

Anand Nene, S. E.