We do get snow, but the places that get blizzarding snow aren't many and there aren't many bridges there to worry about. Railway trestles don't have planked decks to catch snow; it would just fall between the ties (called sleepers in Australia) so there's no risk of being overburdened with piled up snow.
It's nice to agree with someone ;-) Regards, Anthony > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > Bob Sullivan > Sent: Sunday, 19 October 2008 3:25 PM > To: Pentax-Discuss Mail List > Subject: Re: PESO: Covered Bridge > > Anthony, > You have to think about annual rain/snow fall in your dry parts of OZ > vs N.America. > But I do have to agree that we have wooden railroad tressels that last > way over 10 years (100?) > I think the sheds are snow protection. > When you get 4-5 feet of fresh snow on a bridge, removal is problematic, > especially in the horse drawn era. > Regards, Bob S. > > On Sat, Oct 18, 2008 at 10:25 PM, Anthony Farr <[EMAIL PROTECTED]> wrote: > > That's a good explanation, except that wooden bridges have proliferated > > worldwide while covering them seems quite limited. If weather protection > > for the bridge structure was the issue then bridge covering would be > > universal, it's reasonable to think, but it is uncommon except where heavy > > snow falls. However, pedestrian comfort is usually the only justification > > for footbridges to be covered. > > > > Here in Australia are many wooden bridges of great age, often over a century > > old, that have survived uncovered with basic maintenance, giving the lie to > > Wikipedia's claim that, "Wooden bridges tended to deteriorate rapidly from > > exposure to the elements, having a useful lifespan of only nine years. > > Covering them protected their structural members, thus extending their life > > to 80 years or more." > > > > The Straight Dope writer unfairly debunks snow protection by claiming that > > it's the weathering effect of snow that's being argued. AFAIK and have > > read, it's the WEIGHT of the snow, not it's weathering nature, that bridge > > covering seeks to deter. A bridge deck, being flat, could pile up with a > > destructive weight of snow faster than it could be cleared. In a severe > > blizzard, with everyone confined indoors, a bridge could collapse under the > > load of snow before the storm cleared and the snow plough could arrived to > > remove the burden. Putting a pitched roof above the deck prevented snow > > from piling up. Simple as that. > > > > Regards, Anthony > > > >> -----Original Message----- > >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > >> Derby Chang > >> Sent: Sunday, 19 October 2008 8:09 AM > >> To: Pentax-Discuss Mail List > >> Subject: Re: PESO: Covered Bridge > >> > >> > >> A Straight Dope classic > >> > > http://www.straightdope.com/columns/read/1136/why-are-covered-bridges-covere > > d > >> > >> Nice series too, Jack > >> > >> D > >> > >> > > > > > > -- > > PDML Pentax-Discuss Mail List > > [email protected] > > http://pdml.net/mailman/listinfo/pdml_pdml.net > > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
