Sent from my iPad
On Oct 12, 2017, at 17:17, "Jim Thomson" <jim.thom@telus.net> wrote:
> Date: Thu, 12 Oct 2017 14:29:59 -0230
> From: Larry Horlick <llhorlick@gmail.com>
> To: towertalk@contesting.com
> Subject: [TowerTalk] Concrete base - tower
>
> <I am preparing to install a 70' Trylon SuperTitan S500. Nothing is done at
> <this stage...I'm thinking about pouring the base first. Hi.
>
> <The manufacturer has supplied a drawing of the required concrete base. It
> <is a pad and pier design. Doing a pad and pier is significantly more work
> <(i.e. creating the form) than, say, just a rectangular block that I could
> <simply pour in the hole with very little form work.
>
> <My question is...Can do that? Can I change the pad/pier to a block, by
> <altering the dimensions, amount of rebar, etc. to arrive at an "equivalent"
> <to the pad/pier??
>
> <I welcome any relevant comments/questions/suggestions.
>
>
> <Larry
> <VO1FOG
>
> ## pad + pier is a pita. The dirt you put back in there..around the pier,
> that
> sits on the concrete base is...free weight. You can easily dispense with the
> form..but then you will use a helluva lot more concrete..which is OK per
> Trylon.
> But the re-bar setup is different.
>
> ## If ground is clay, or solid enough, so the sides of the hole dont cave
> in,
> you dont require the megabuck, pita wooden form. Flip side is.... the
> wooden form
> is very expensive to build. It comes out a wash, or close to it. Cost of
> wooden form
> vs cost of extra concrete.
>
> ## If a wooden form is used, it has to be carefully constructed. Concrete
> weighs aprx
> 4000 lbs per cubic yard....= 150 lbs per cubic foot. There is a huge
> stress on the wooden form as is.
> There is also a huge stress on the portion of the wooden form that
> encompasses the pad. Thats from the
> sheer vertical compression weight of the concrete in the pier. Get it
> wrong...and form starts to come apart
> when you have poured 80% of the concrete into the form.... u are in for a
> rude awakening.
>
> ## Even if it all goes ok, the wooden form has to be removed. Which means
> the hole has to be big enough
> to work in. IE u gotta be able to get down into the hole and squeeze
> between the dirt side walls and the
> wooden form, to dismantle the wooden form. Here in BC, if the hole is 6 ft
> deep, or deeper, the dirt sides have to be shored up,
> which involves yet a ton more wood. WCB here in BC will severely fine any
> contractor violating shoring regs.
> Ok, now you toss the wood into the scrap heap, never to be used again.
> It would be a different story IF you are a contractor, and are installing
> 4-10 identical towers, and the expensive
> wooden form can be re-used.
>
> ## BTW, AN wireless, who makes a similar product, depicts BOTH methods on
> their website. The owner tells me
> nobody uses the wooden form and pad and pier method. Sure, you save some
> $$ on concrete, then you lose it all
> on the wooden form, and elaborate re-bar bending.... PLUS a ton more effort
> and time involved with the form + pier + pad.
> Contact Trylons eng dept.... and they will provide you the... normal base
> diagram..which is not on their website. Local tower
> contractor has installed the newer Trylon Super titans for commercial
> use...and none of em used a pad + pier. Besides the cost
> of the form...+ shoring, there is a ton of expensive labour involved, both
> building the form + shoring, and removing it.
> A lot quicker to just dump more concrete in. BTW, dont use anything less
> than 30 MPA concrete. 30 mpa is 50% stronger than
> 20 mpa, and you wont end up with any hair line cracks....esp in winter, with
> sub freezing temps. If I remember correctly, the pad
> + pier method also involved installing styrofoam sheeting on top of the
> exposed pad, after the form removed.
> That depended on how deep the frost line is. It was typ 1-2 inches thick.
> More pita. You dont require any of this with a giant
> block of concrete. I was going to install a 90 or 100 ft of super titan,
> with the 6 ft wide base...at my daughters place, since
> she was on 5 acres. She ended up selling it...and moving to denman
> island...now on 11 acres. I gave up on that project. The logistics
> of driving 150 miles each way, was too much. On the island, its then a 10 min
> ferry trip each way, on top of the drive. And concrete
> on that island shes now on is stupid expensive.
>
> Later.... Jim VE7RF
> _______________________________________________
>
>
>
> _______________________________________________
> 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
|