Bridges ought to be supported from above, especially on rivers with traffic. Helium or hydrogen filled balloons will have cables attached to them, supporting the bridge below.

Pumps will be set to reduce the volume when the traffic on the bridge decreases. Conversely, the canisters will have valves that open to maximise the balloon volume during rush hour.

No more collapsed piers and related accidents!
-- neelandan, May 28 2002

Hungerford Bridge http://www.integer-...o.uk/Hungerford.htm
[stupop, May 28 2002, last modified Oct 21 2004]

So instead of barges crashing into the piers, you have aircraft hitting the balloons and cables.
-- angel, May 28 2002


This might work until some Saudi millionaire decides the balloons would make a good target.

How about "No bridges"? With a ramp on each side, a minimum speed of 100 km/h and you fly right over.
-- FarmerJohn, May 28 2002


[angel] you beat me to it!
-- FarmerJohn, May 28 2002


Please, moratorium on helium-related ideas. Helium (or even hydrogen) is crap and can lift very little. Look at the size of an airship that carries 20 people: now how big will the balloon for your bridge need to be?
-- pottedstu, May 28 2002


Vacuum? Hot air?

Perhaps a small hot air balloon and powering it . . . Vernon.
-- neelandan, May 28 2002


Many bridges are supported from above, they are called suspension bridges.

High winds would make the bridge sway like anything.

Best idea is just to build stronger piers or some sort of device that stops ships from hitting them.
-- ferret, May 28 2002


What you want is a ship impact beam. The new Hungerford Bridge on the Thames has one to protect the old railway bridge which it flanks. Apparently it's capable of withstanding 30MN.
-- stupop, May 28 2002


30 Minnesotas? Wow.
-- bristolz, May 28 2002


FJ, been watching the Blues Brothers again?

If we all simply switched to amphibious vehicles this would eliminate the whole issue.
-- rbl, May 28 2002


A few rounds from a gun could pierce these balloons. Unless you use some other material.

Stick to piers and normal bridge materials.
-- Spread, Jun 02 2002


That's a heckuva lotta Minnesotas, there, don'tcha-know.

London bridge is falling up, falling up, falling up...
-- waugsqueke, Jun 03 2002



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