How much?

[Legbreaker]

My thoughts are that unless you've got a LOT of time AND explosives available, the piers aren't worth troubling with. Build to withstand not just the weight of the bridge, but flood waters as well, unless they've been constructed with demolition chambers built in, they're not going anywhere in this lifetime...

[jester]

I mean the steel structure above the piers, the piers or pillings are usualy concrete, and the footing of the bridge is usualy steel imbeded into the concrete. Where they merge however, you have to different materials joined, and that is usualy the weak spot. A meter or so up and you have all those stresses. The charge on the concrete pilling is more to cause a shacking of the bridge once its been damaged to help loosing up what has already been damaged or weakened by the prior explosives so that gravity can do its job.

Also, look at places where a steel pole is imbeded into concrete, there is always rust on the steel, again a weak spot that should be checked and exploited.

[pmulcahy11b]

Think about the Paul Doumer Bridge in North Vietnam. I'll grant you, it's not the same in situation or size (2500 feet cantilever construction), only analogous -- but the US repeatedly tried to drop that bridge and succeeded only in 1972 when smart bombs became available -- and then only put it out of service for a year.

I'm just saying -- it's never as easy as one thinks. That old military axiom, "No plan survives first contact."

[Targan]

I like Jester's idea of cutting through the steel support beams with thermite grenades. Most load-bearing points on a bridge like that will be too thick to cut through with det cord (if it was a suspension bridge det cord would be a viable option).

[kato13]

This took 75 lbs or RDX and 350 shaped charges. Kinda beyond the scope of the mission but it is a pretty picture.

[pmulcahy11b]

Originally Posted by kato13

This took 75 lbs or RDX and 350 shaped charges. Kinda beyond the scope of the mission but it is a pretty picture.

Is that the former Skyway in Tampa?

[kato13]

Originally Posted by pmulcahy11b

Is that the former Skyway in Tampa?

Jamestown Bridge in Rhode Island

[jester]

Originally Posted by kato13

This took 75 lbs or RDX and 350 shaped charges. Kinda beyond the scope of the mission but it is a pretty picture.

But, I see three different secontions falling in the photo. So, what if you just wanted to drop 1 section? That is all I propose, drop a wide enough section to make it beyond use.


Unless there is damn upriver where a esxplosives genious and a mountainclimber turned explorer can blow which will release a torrent of water that will take out the brigde. If that's the case then the problem is solved.

[Grimace]

Make sure you all wave to the nice FBI agents reading this page!

As far as taking down the bridge, your best bet would be to damage one of the main supports enough with all the explosives you can that it weakens the bridge. Then, like smokewolf suggested, you let the enemy run their convoy on to the bridge and let it collapse from the weight upon the weakened section. Thus topples the section of bridge while inflicting losses upon the enemy convoy.

You can plan all you want, but trying to run a covert op against a bridge like that, without having access to all of the nifty gadgets, gizmos and extractions equipment necessary for proper insertion and extraction will result in a big hairy mess that leave any major plans largely undone.

Make it quick, make it simple, and throw all your explosives at one major point in hopes of successfully weakening the main support structure of the bridge enough that weight and/or nature will bring it down. If you're real lucky, or have more explosives than I think you could probably, reasonably have in Twilight, then you might just be able to drop a section of the bridge right away. It won't be pretty, it won't be quiet, but if you just want something "blowed up", you throw enough explosives at it and it'll drop.

Oh, and it would also help out in a major way if you've got either a civil engineer or a very, very good combat engineer who can pinpoint the exact points, the minimal exact points, that would be best to plant the explosives to cause the greatest weakening effect on the bridge.