subgrade tie rods. I'm not too comfortable using passive soil pressure
unless the magnitude is very low (less than the at-rest pressure). You
should get pretty significant movement to activate the passive pressure.
Though you'll get noticeable elongation in the tie bars as well, at
least that can be calculated and - in theory - will not be permanent for
transient loads. For example snow load taken by passive pressure is a
permanent deformation of the soil, whereas is should be elastic with a
tie rod. Now, that won't be perfectly true, as friction will prevent the
tie rods from returning to zero deformation, but that friction will also
provide a certain measure of safety.
Jordan
Kevin Below wrote:
> For an indoor sports stadium with 200-ft span, I have seen several
> examples using huge curved glu-lam beam sections about 6 ft high, at
> about 30 ft spacing. These beams are assembled on-site into a
> 3-pinned arch configuration (a pin at each support, and a pin at
> mid-span.)
> The horizontal reaction at the base pins is enormous, and exceeds the
> vertical reaction. For example, 470 kips horizontal, and 405 kips
> vertical. The horizontal reaction is provided mostly by passive soil
> reaction on the perimeter wall.
> Is this good enough ? Any thoughts on that ?
> Is the passive reaction going to allow movement before it mobilizes
> ? Enough to be noticeable ?
> What about seismic effects on the soil behind the wall ? Will it
> cause the soil to move under the pressure from the arches ?
> What about a tie-rod (it would need to be big) under the sports
> surface, tying the 2 sides together ?
>
> Kevin
>
> kbofoz
>
******* ****** ******* ******** ******* ******* ******* ***
* Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
* This email was sent to you via Structural Engineers
* Association of Southern California (SEAOSC) server. To
* subscribe (no fee) or UnSubscribe, please go to:
*
*
http://www.seaint.org/sealist1.asp
*
* Questions to seaint-ad@seaint.org. Remember, any email you
* send to the list is public domain and may be re-posted
* without your permission. Make sure you visit our web
* site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********