[AusNOG] Brisbane gets "NBN" early??

[Bevan Slattery]

Spot on Adam.  And there was a real problem to when the engineers of the M1 pointed out that when they designed the entire concrete base for the freeway they didn't factor in some muppet was later going to neatly cut a 6 -12 inch grove through it drastically diminishing it's engineered strength.  It's not dissimilar to designing a floor in a building that's 300mm deep to carry load and then getting a diamond blade cutter and cutting a 150mm-200mm groove right down the middle and filling it with epoxy.  Do you think any engineer would think that's a good idea?  There is a reason the floor was designed 300mm deep WITHOUT the grove.

This is less of an issue elsewhere, but people need to think a little bit before you do this stuff everywhere.  There is a reason that Telco has historically been at least 600mm deep too.  How is anyone going to "cross" a microtrenched service once it's in place?  The risk of damage is very high.

It has it's place and is good in some applications.  But it has some serious design issues with the main one being the risk of damage due to the installation of other services and resealing of roads.

Cheers

[b]

> -----Original Message-----
> From: ausnog-bounces at lists.ausnog.net [mailto:ausnog-
> bounces at lists.ausnog.net] On Behalf Of Adam Griffiths
> Sent: Friday, 15 October 2010 2:45 PM
> To: ausnog at ausnog.net
> Subject: Re: [AusNOG] Brisbane gets "NBN" early??
> 
> On Thu, Oct 14, 2010 at 10:04 PM, Andrew Fort <afort at choqolat.org> wrote:
> > On Thu, Oct 14, 2010 at 9:01 PM, phil colbourn <philcolbourn at gmail.com>
> wrote:
> >
> >> So, they ran a point-to-point optical fibre 1.4km long in a sewer
> >> pipe and it worked! Amazing.
> >> "microtrenching cuts a slot around 600mm deep and 20mm wide in which
> >> the cable is laid"
> >
> > Oh dear.  Someone might suggest they run a testbed microtrench next to
> > a road, and leave a test fibre "in the groove" for a year or more.
> > They may be surprised with where the fibre ends up.
> >
> 
> Uecomm used a significant amount of microtrenching in the early 2000's (a
> few 100's km of it across most states) but pulled it all out at very significant
> cost. The main problem being that bitumen is not rigid/solid and after a few
> 100,000 vehicles the cable pop's to the top of the road.
> 
> Particularly bad problem in QLD with the increased temperature
> 
> Works well in environments were roads are constructed of concrete, but
> that's not the norm in Australia.
> 
> AG
> 
> > -a
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