[TowerTalk] PIPE ANCHORS

[Kipton Moravec]

On Mon, 2011-10-31 at 19:34 -0700, Jim Lux wrote:
> On 10/31/11 2:02 PM, Dorn Hetzel wrote:
> > But of course, filling the pipe or square tube with concrete probably
> > does help since bending would have to compress the concrete
> > fill and concrete *seriously* resists compression.  Especially if the
> > interior of the tube is rough enough for the concrete to bond
> > to it well (or some bolts are run through or such).
> >
> 
> 
> I'm not sure about that.  I looked through a bunch of references, and 
> nobody seems to have measured the strength with/without concrete.
> 
> Yes, concrete is strong in compression, but think about a pipe full of 
> concrete and bending.  It stretches on the far side, and the concrete 
> just cracks.  Concrete isn't very strong in bending.
> 
> Overall, I don't think concrete fill buys you a lot, structurally, 
> unless you're doing something like a prestressed concrete beam, so the 
> side away from the load doesn't ever get into tension.
> 
> Even in the compression side, the steel probably is stronger than the 
> concrete in compression.  Concrete's big advantage is that it's cheap 
> compared to steel.


http://www.ctsee.org.tw/pdf/200310/ee0401-05.pdf