Yeah!! Talk about overkill........
On Thu, 2 Sep 2010 10:34:23 -0500 Michael Goins <wmgoins@gmail.com>
writes:
> Good Lord. Whatever happened top Joe Average Ham and just pouring
> concrete
> for a base? I can see all this if you have an gigantic hundreds of
> feet high
> superstation, but the average guy doesn't need to have his concrete
> analyzed.
>
> You dig the hole the tower manufactuer specifies and you use the
> rebar/cage
> they say. You guy correctly if it is guyed tower. You add concrete
> and make
> sure there aren't voids. 99.999% of us need nothing more than that.
>
> Mike, k5wmg
> Pipe Creek, Texas
> Green cars, slow boats, big dogs, old trucks, little radios, and
> summers off
> to write
>
>
>
>
>
>
> On Thu, Sep 2, 2010 at 8:22 AM, Jim Thomson <jim.thom@telus.net>
> wrote:
>
> > Thank you for the suggestions.
> >
> > I called Advanced Testing in my area and got some information.
> First, I
> > checked the trustworthiness of the concrete company.
> > That checked out. The technical person I spoke with had a lot
> experience
> > with concrete testing and curing. A 4" slump and
> > no more for this job.
> >
> > ### When those 4 x cylinders are poured, [all at the same time]
> the 1st
> > cylinder is put in the hydraulic squasher after 7 days.
> > Cyl #2 gets tested after 14 days. Cyl #3 after 21 days....and
> #4 after
> > 28 days. I never have it done...unless a PE says to do it.
> > If more than one cement truck is involved.... then you have to
> obtain 4 x
> > samples from each truck ! Everything has to be labeled.
> >
> >
> >
> >
> > However, due to the very warm temperatures in the north east, I
> should
> > cover it with plastic to keep
> > the moisture from evaporating off the top.
> >
> > ## whoa! Make damn sure u use a 15' long vibrator with at
> least a 1.5"
> > head on it..and don't over
> > vibrate the concrete. They are cheap to rent. You can also get
> em with
> > a 2" diam head. Both heads
> > are aprx 12" long. Stuff the vibrator in, and turn it on... and
> it will
> > flatten a mound of cement in 1 sec flat.
> > You can also drag it across..and make concrete flow into the
> corners, or
> > where you want it. Another trick
> > is to vibrate the cage itself..or the form. You need one person
> to
> > operate the vibrator..and a 2nd
> > person to turn the switch on/off.
> >
> >
> >
> > ## A lot of times the cement truck operator will ask you if you
> want it
> > wetted down a bit..
> > so it pours easier. If you add water.. you will weaken the mix.
> If
> > there is any standing water in the
> > bottom of the hole..it will weaken the mix as well... and has to
> be pumped
> > out.
> >
> > ## some folks will lightly spray the sides of the hole with
> water... to
> > slow down any evaporation on the 5 x sides.
> > Some will line the 4 x vert sides with 4-6 mil plastic
> sheeting..to do
> > the same thing.
> >
> > ## as far as the top goes... AFTER troweling is done... I cover
> all exposed
> > concrete with old [clean] bed sheets.
> > Then let it set up for an hr. Then LIGHTLY mist it with the
> water
> > sprayer. Then do it again an hr later... with progressively
> > more water. You will find that the top of the concrete block
> will suck
> > the water right up.... and then the chem
> > reaction starts up. A few mins later... you can feel the heat
> pouring
> > out the top of the wet sheets ! I repeat the
> > same process [esp on a hot day] for abt 6-7 days in a row.
> If the
> > concrete is poured at 10 AM... it's still getting water
> > on it at midnight..and quickly gets sucked up. It's dry as a
> bone very
> > quickly..depending on outside temp.
> > You won't end up with any hair line cracks either..not with the
> top closed
> > off..with a layer of rebar 5" below it.
> >
> > ## I just pumped in 17 x yards of 5075 psi [35 mpa]
> concrete on Aug
> > 16th.....it's still curing. I had to morph
> > the new UST HDX-689 base into the adjacent old Trylon base.
> [which is
> > flared on all 4 x sides] One side of the
> > old base forms one side of the new base. Old base is 5.5'
> square x 6'
> > deep. New base is 7' x 6' 3" x 9' deep.
> > 1025 lbs of rebar went into the new base. 1" for the 24 x
> verticals. [
> > UST uses 16 vertical's]... and 5/8" for the
> > 14 x horizontal tires. Ties are spaced every 6" for the 1st 10 x
> ties..
> > then every 1' for the last 4 x ties.
> > Both vert + Horz are 60 ksi weldable material. The 12 x
> anchor rods
> > are 5' long with 6" threads on each end.
> > 105 ksi rods used. They are in 3 x grps of 4 each... on 5'' C
> to C.
> > Instead of the usual flatwashers on the bottoms of the
> > rods... we used a 9" x 9" x 1/2" thick steel plate...with 4 x
> holes
> > punched. That alone increases the
> > pull out capacity through the roof.
> >
> > ## Local PE and city hall wanted the cage closed off on the top
> too..with
> > a 8x6 grid of bars....
> > and also a 2nd parallel grid of bars down 4.5'. The reason
> was to
> > surround the 12 x anchor
> > rods on all SIX sides. UST spec's a 4.5' square cage.
> We used a
> > 5.5' square cage. UST sez to use
> > short 27" long anchor bolts [ 55 ksi]..we used 60" long rods
> [105 ksi]
> > IMO... 27" long anchor bolts
> > seems strange. You have 6" of threaded rod above the concrete
> [which is
> > already 6" above the lawn]
> > That only would leave 15" of anchor bolt below lawn level !
> I can't
> > see digging a 9' deep hole...
> > and having 15" rods embedded. Local PE wanted the depth of the
> rods to
> > be at least 1/2 the depth of
> > the hole. It was decided that since the 105 ksi rods are only
> 13% more
> > $$... but are 91% stronger, to
> > use the stronger stuff. So in went more re-bar, etc. Since a
> line pump
> > was used this time... the mix
> > used 3/8" aggregate [ so the 3" line pump won't clog] . Took 55
> mins to
> > pump in 17 yards..with the
> > load split between 2 x trucks. I hope city hall is happy. 17
> yards in
> > new base morphed into 8 yards
> > of old base = 50.625 tons. I'm sure a hellfire missile would
> bounce
> > off it. I have pix of all this.
> >
> > Sri for the diatribe.
> >
> > later... Jim VE7RF
> >
> >
> >
> >
> >
> > I will keep the group posted and post more pictures.
> >
> > Thanks.
> >
> > Anthony
> > _______________________________________________
> >
> >
> >
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> >
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