The Rotherhithe Tunnel is closed for 7 hours every Monday night for routine
maintenance. The Blackwall Northbound tunnel is closed every Sunday a.m.,
with the southbound tunnel carrying northbound traffic only at that time
(mostly). Why do these two tunnels need maintenance and the Blackwall
Southbound doesn't? I am not aware of any bridge having this sort of
maintenance schedule, so I'm wondering why tunnels are ever built if they
need so much maintenance.

--
We are the Strasbourg. Referendum is futile.

"Basil Jet" wrote in message
...

The Rotherhithe Tunnel is closed for 7 hours every Monday night for
routine
maintenance. The Blackwall Northbound tunnel is closed every Sunday
a.m.,
with the southbound tunnel carrying northbound traffic only at that
time
(mostly). Why do these two tunnels need maintenance and the Blackwall
Southbound doesn't? I am not aware of any bridge having this sort of
maintenance schedule, so I'm wondering why tunnels are ever built if
they
need so much maintenance.

I believe they close the Northbound and Southbound Tunnels on alternate
weekends. Whichever tunnel is closed, northbound traffic uses the
remaining one while southbound traffic is diverted.

Peter Smyth

On Mon, 14 Dec 2009 23:54:14 -0000, "Basil Jet"
wrote:


The Rotherhithe Tunnel is closed for 7 hours every Monday night for routine
maintenance. The Blackwall Northbound tunnel is closed every Sunday a.m.,
with the southbound tunnel carrying northbound traffic only at that time
(mostly). Why do these two tunnels need maintenance and the Blackwall
Southbound doesn't?


There was a fire in the northbound bore of the Blackwall Tunnel last
week. Presumably that is the reason why the work is needed.


I am not aware of any bridge having this sort of
maintenance schedule, so I'm wondering why tunnels are ever built if they
need so much maintenance.


Tunnels tend to need cleaning and their ventilation systems require
regular maintenance. Why do you consider those things unreasonable?

Bruce wrote:
On Mon, 14 Dec 2009 23:54:14 -0000, "Basil Jet"
wrote:


The Rotherhithe Tunnel is closed for 7 hours every Monday night for
routine maintenance. The Blackwall Northbound tunnel is closed every
Sunday a.m., with the southbound tunnel carrying northbound traffic
only at that time (mostly). Why do these two tunnels need
maintenance and the Blackwall Southbound doesn't?


There was a fire in the northbound bore of the Blackwall Tunnel last
week. Presumably that is the reason why the work is needed.

This has been going on for several years.

I am not aware of any bridge having this sort of
maintenance schedule, so I'm wondering why tunnels are ever built if
they need so much maintenance.

Tunnels tend to need cleaning and their ventilation systems require
regular maintenance. Why do you consider those things unreasonable?

I didn't say they were unreasonable, I just wanted the people who know why
this is reasonable to help me become one of them. I see no confrontation in
my original post.

--
We are the Strasbourg. Referendum is futile.

On Tue, 15 Dec 2009 00:44:01 -0000, "Basil Jet"
wrote:

Bruce wrote:
On Mon, 14 Dec 2009 23:54:14 -0000, "Basil Jet"
wrote:


The Rotherhithe Tunnel is closed for 7 hours every Monday night for
routine maintenance. The Blackwall Northbound tunnel is closed every
Sunday a.m., with the southbound tunnel carrying northbound traffic
only at that time (mostly). Why do these two tunnels need
maintenance and the Blackwall Southbound doesn't?


There was a fire in the northbound bore of the Blackwall Tunnel last
week. Presumably that is the reason why the work is needed.

This has been going on for several years.


Peter Smyth's reply has the answer.


I am not aware of any bridge having this sort of
maintenance schedule, so I'm wondering why tunnels are ever built if
they need so much maintenance.

Tunnels tend to need cleaning and their ventilation systems require
regular maintenance. Why do you consider those things unreasonable?

I didn't say they were unreasonable, I just wanted the people who know why
this is reasonable to help me become one of them.


Bridges aren't an option for the Blackwall and Rotherhithe tunnel
routes. The bridges would have to offer full navigable clearance so
that tall ships could enter the Pool of London. So they would have to
be as tall as the bridge that forms the southbound Dartford-Thurrock
crossing, with very long approach ramps. There's no land available
for all that. The proposed East London River Crossing is only a
possibility because there is land available there.

Tall bridges are very difficult and expensive to access. So they are
designed to be maintenance free as far as is practicable, which adds
to their initial cost.

As I said, tunnels need cleaning - both the road surface and the
inner, visible lining that hides the structural tunnel lining. They
also have drainage, ventilation, lighting and safety (fire) systems
that need maintenance so as to be kept in full working order,
otherwise the tunnel could not be used. Any tunnel under a river (or
below the water table on land) is subject to great water pressures
causing leaks and potential corrosion of the tunnel lining. So the
lining needs to be maintained to exclude water.

But I somehow doubt that this will convince you to become a
tunnelophile. :-(


I see no confrontation in my original post.


Neither do I! ;-)

"Basil Jet" wrote in message
...

The Rotherhithe Tunnel is closed for 7 hours every Monday night for
routine
maintenance. The Blackwall Northbound tunnel is closed every Sunday a.m.,
with the southbound tunnel carrying northbound traffic only at that time
(mostly). Why do these two tunnels need maintenance

Blackwall West (i.e. northbound) Tunnel opened 1897.
Rotherhithe Tunnel opened 1908.

and the Blackwall Southbound doesn't?

Blackwall East (i.e. southbound) Tunnel opened 1967.

I am not aware of any bridge having this sort of maintenance schedule

I seem to recall Albert Bridge (a structure of similar age to the oldest of
these tunnels) being closed at weekends in the past. At least half of
Blackfriars railway bridge is out of action at the moment to allow for
refurbishment prior to alterations in association with the Thameslink
programme, and ISTR a lot of the roadway over Westminster Bridge being out
of service for long periods during refurbishment over a two year period from
2005 to 2007. In fact, most of the current Thames bridges in central London
are replacements for previous structures that wore out or otherwise became
inadequate for modern traffic.

D A Stocks

Westminster bridge was indeed restricted to road traffic, with
hoardings up for several years.

The Forth rail bridge was continuously repainted until a short while
ago; with modern paints it now only needs repainting every 10 years.
That work may not yet be complete!

The forth road bridge, meanwhile, is in need of repair, whilst in the
recent floods in Cumbria many more were swept away.

On Tue, 15 Dec 2009 03:41:49 -0800 (PST), stan5001
wrote:

Westminster bridge was indeed restricted to road traffic, with
hoardings up for several years.

The Forth rail bridge was continuously repainted until a short while
ago; with modern paints it now only needs repainting every 10 years.


30 years, ITYF.


That work may not yet be complete!

The forth road bridge, meanwhile, is in need of repair, whilst in the
recent floods in Cumbria many more were swept away.


The Forth and original Severn (road) bridges have corrosion in their
suspension cables which is reducing their load capacity.

On Mon, Dec 14, 2009 at 11:54:14PM -0000, Basil Jet wrote:

The Rotherhithe Tunnel is closed for 7 hours every Monday night for routine
maintenance. The Blackwall Northbound tunnel is closed every Sunday a.m.,
with the southbound tunnel carrying northbound traffic only at that time
(mostly). Why do these two tunnels need maintenance and the Blackwall
Southbound doesn't?

Perhaps the southbound tunnel has already had its maintenance and
they're now doing the northbound one - better to keep one open than
close both.

--
David Cantrell | London Perl Mongers Deputy Chief Heretic

What a lovely day! Now watch me spoil it for you.

"Bruce" wrote in message



Bridges aren't an option for the Blackwall and Rotherhithe tunnel
routes. The bridges would have to offer full navigable clearance so
that tall ships could enter the Pool of London. So they would have to
be as tall as the bridge that forms the southbound Dartford-Thurrock
crossing, with very long approach ramps. There's no land available
for all that. The proposed East London River Crossing is only a
possibility because there is land available there.

Tall bridges are very difficult and expensive to access. So they are
designed to be maintenance free as far as is practicable, which adds
to their initial cost.

There's also the little matter of London City airport -- high bridges
simply aren't an option anywhere close to its flight path.