Bridges Are Us

[robnisch]

Engineers say a cable-stayed bridge could be in Port of Baltimore’s future

Given the contours of modern ships and the Port of Baltimore, engineers see a cable-stayed bridge in the city’s future.

www.baltimoresun.com

There must be some structural engineers on these forums.
I have a little old knowledge of the subject.
It would seem that the trend is cable suspension. Like the new bridge going from Detroit to Windsor.
Thoughts?

 

[bilby]

The choice appears to be dictated more by fashion than by any structural questions. All the major bridge types seem to be structurally sound and in a similar ball-park price-wise, though if you want a high clearance and a long span (as you must over a major shipping lane), the only real options are suspension, cable-stayed, or cantilever. The later being most expensive, but having a lower profile - so they are useful near airports, where you need to have a high water clearance for ships, but also a low maximum height.

The fashion in the 1980s and '90s was for suspension bridges; Today it seems to have swung towards cable-stay designs.

Then there's the soon-to-open Neville Bonner bridge across the Brisbane river, which was designed by a committee who, unable to agree on what kind of bridge to build, built one that was a bit of everything.

 

[steve_bank]

My guess would be cost is the issue.

If a suspension bridge uses less steel it is cheaper.

It may be cheaper to build.

Try searching on 'suspension bridge costs versus other designs.'

There should be sites that go through the structural design issues and tradeoffs.