-
Asked by themoderator to Ed, Keith, Tish, Nicola, Rachel on 11 Mar 2013.
-
Nicola Lazenby answered on 11 Mar 2013:
This all depends on what it is a bridge across, how much money you have and what the purpose is……
1 – you have something like the Humber bridge – designed in a design office, made from steel over a number of years….
or
2 – you could have something like this: http://www.digplanet.com/wiki/Log_bridge – still designed by professions, but for totally different reasons! This bridge might look very simple, but in reality it saves millions of lives each year as it means that the villages might not have to cross a river polluted with all sorts of nasties which would make them ill!
-
-
Natasha Watson answered on 13 Mar 2013:
Agree with Nicola, it all depends on what the bridge is spanning, what materials you have available are, what money you have, what is it meant to be carrying etc. Just because I think it’s awesome, here is a photo of a bridge made from living trees…. very very cool http://unitarianchurchnortheastindia.blogspot.co.uk/2011/02/living-roots-bridge.html
-
Edward Taylor answered on 13 Mar 2013:
I think the biggest questions you have to ask before building your bridge are:
– how wide does it need to be (what’s going to be crossing it?)
– how high does it need to be (does anything need to go under it!?)
– how strong does it need to be (how heavy will the people/cars on it be?)once you have those answers you can start designing, making sure that you fulfill all those requirements.
As engineers we always overdesign things with a “reserve factor”, just to be sure they will work. What that means is, if you expect the bridge to have 10 people on it at a time, you would design it to be strong enough to hold 30 people. That way you can be sure it’s safe! We put reserve factors on absolutely everything, so you can rest assured that you are safe when you are in planes, cars, buildings, bridges, trains etc!
Comments