|WikiProject Bridges||(Rated Start-class, High-importance)|
I just came across this page. I feel there is real issue with it as it is basically just a list of Vertical-lift bridges. I think it needs more information on:
- How they work.
- Purpose of them. (Advantages over other bridge types)
- The history of their use.
- Variations in design (if there are any).
There only needs to be a few notable bridges on this page. The main list below should be moved to a different page i.e. List of vertical-lift bridges.
I have put a request for a photo of Pretoria Bridge in the Up position, in Wikipedia:WikiProject Ottawa. It has been removed from the Lift Bridge article as someone did not believe it was a lift bridge. The Bridge is a lift bridge, not a tilt bridge, although the mechanism is located underneath. cmacd 14:57, 5 February 2007 (UTC)
Image copyright problem with Image:Teesnewportbridge.jpg
The image Image:Teesnewportbridge.jpg is used in this article under a claim of fair use, but it does not have an adequate explanation for why it meets the requirements for such images when used here. In particular, for each page the image is used on, it must have an explanation linking to that page which explains why it needs to be used on that page. Please check
- That there is a non-free use rationale on the image's description page for the use in this article.
- That this article is linked to from the image description page.
Can people/vehicles be on the bridge when it lifts?
This seems to me a potential advantage of vertical lift bridges and swing bridges over other movable bridge designs – it isn't necessary to wait for traffic to clear the bridge before making way for a ship. This would be especially useful at busy times, as traffic using the bridge can go onto it without having to worry about whether there is enough clear road space at the other end.
Of course, it would rely on the bridge's mechanism being strong enough to lift the weight of traffic on the bridge and to support this weight in the raised position. But how often is this the case? At the moment the article doesn't comment on this at all. It would be nice to find some information on this. I haven't taken time to go through all the articles on individual vertical lift bridges to see if they comment on the matter, but maybe somebody who is familiar with one or more of these bridges can enlighten. — Smjg (talk) 19:50, 8 March 2015 (UTC)
- There is a safety advantage. If for whatever reason the bridge operator doesn't see a slow pedestrian and opens the bridge prematurely, the pedestrian doesn't fall off.
- The winches opening the bridge are designed for a force equal to the weight of the span minus the weight of the counterweight, plus something for friction, acceleration and unequal weight of the cables, which is far less that the weight of the span. Putting some vehicles on the bridge may add significantly to the force that the winches have to pull, so they may not be able to raise the bridge. A few pedestrians wouldn't be a problem and I assume people sometimes let themselves be hoisted up, even if it's illegal, to watch the view from above.
- I'm not aware of any vertical-lift bridges that open with traffic on them, and I know several vertical-lift bridges in the Netherlands. None of them have barriers on the lifting span to keep people on them from driving off while in raised position. Furthermore, if the bridge has a malfunction and gets stuck, people could get trapped. So I think you can assume the bridge operator always waits for the traffic to clear, which shouldn't take more than a minute anyway (except for slow pedestrians, like people with a walking aid). But practices may vary in other parts of the world. PiusImpavidus (talk) 15:31, 10 November 2015 (UTC)