A little googling and it appears that testing now verifies that long
free falls aren't detrimental, but inspectors may not all agree, at
least that is my somewhat aged experience. Same for free fall pouring
into 8 feet of water.
I'm surprised that free fall pouring into 30-50 feet deep water in a
caisson is ok. Pouring into some water at the bottom sounds more
reasonable.
So better ask your inspection dept what is ok.
I was building over the Silicon Valley "plume". Underground water flow
with TriChlor etc contamination from electronics making in the 50' and
60's. The engineers said "we can't dig deeper than 2 feet" or we will
trigger remediating $$$$.
Grant KZ1W
On 5/27/2020 16:49, Steve Maki wrote:
On 05/27/20 19:34 PM, Steve Maki wrote:
On 05/27/20 19:15 PM, Grant Saviers wrote:
Actually it is ok to pour concrete into a wet hole if the concrete is
pumped in from the bottom. The water rises right out. Not ok to drop
concrete into water. The mix plant, pumper and driver know how to
adjust the mix a bit.
Hmm - that's not my experience. When we (drillers hired by me) install
caissons for tall monopoles and self supporters with 30'-50' deep
caissons, they just dump the concrete in. They use temporary
cylindrical forms to prevent cave-ins, but pay little attention to the
water down there. These operations are always monitored by 3rd party
engineering firms. On the reports I usually see *freefall concrete
placement*.
Or have a PE design a different base, there are all sorts of
alternatives, plates, piers, wider and shallow, etc. As long as the
base resists the overturning moment and shear. The stock foundation
UST wet stamp is on the web so should be a easy and quick job for a
PE (unless they want a soils test, which in theory... but local
knowledge of conditions often is acceptable).
Agreed. A suitable foundation can be designed for above ground
placement if you don't mind the ugliness and the concrete cost. The
key is to get it engineered properly.
In fact there are many 70'-100' cellular monopoles around Detroit on
ballast mounts. Often to avoid what is beneath the surface.
-Steve K8LX
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|