How much?

[jester]

Lets look at some of the attempts by the Germans to take out the railroad bridge at Remagen.

Shelling it is costly, it would take pinpoint accuracy and lots of shells. Are the resources available? And would the Russians mount a counter attack?

Scuba divers with demolition charges on the underwater footings. This is possible, but is it practical? Do you have well trained divers and knowledge of the bridge and the pillings and riverbottom material? And of course a launch point that is secure to launch your forces from? And of course the materials, scuba or more likely rebreater gear, wet suits or dry suites, lights, timmers, igniters, lots of det cord to connect the charges and to use as wrapping to cut steel beams. And, of course the amount and quality of the explosives.

A comando force can sneak in and place charges on the reinforcing beams they can do this stealthfuly, placing them surgicaly, wraps of det cord and specific ammounts of charges in the support structures and key points that will allow it to fall under its own weight. The down side, you need to be stealthy and if caught you are screwed, or doing everything underfire which of course will cause the chances of failure to increase.

Or, just sieze the bridge! Go in, sieze it. On force conducts a holding action against the Russians trying to retake the bridge. A second force goes to work with torches and placing demolitions to weaken the bridge and ensure it falls when the charges go off. Downside, it can be a suicide mission for those on the bridge. They sit tight until it blows. OR, they can either escape via boats they have waiting below the bridge, or simply dive into the water and swim for it. Of course to ensure that is successful, you would want to place ALOT of anti personel mines and booby traps to slow up the enemy so they do not make it to tamper with your main charges.


As for me, I'd go for the stealth aproach. Wetsuited combat swimmers with demo packs placing the charges at the bridges footings where the steel meets the concrete and tamp them. If the footing of the bridge is parted it will come down. I would also use thermite bombs and det cord to cut through alot of the support beams. The cool thing, you only need to attack one side of the bridge, left or right side, one side of the bridge comes down it is unusable, all the forces will take it down, as you have longer spans that are unsupported. And when it comes time to rebuild, you still have 1 side still standing to possibly use should you want to rebuild.

Also, it would be a good idea to somehow cut the upper supports atop the bridge as they tie in alot of the support for the bridge.

Anyhow, those are some of the ways I would take it down. As for suppliest 2 dozen thermite grenades, 4 to six rolls of detcord, 8-12 satchell charges, 8 waterproofed satchell charges with enough detcord to connect them and two timers and shock cord or instant fuse.

Working primarily on one side, the upriverside would be my choice so you have the forces of the water working for you once the charges do blow.


1.) Thermite bombs go off burning through support structures that they are best suited to cut through. Lesser beams, steel support cables and similiar.

2.) Cutting charges blow cutting support structures, supporting and reinforcing beams and such.

3.) Cutting charge at the footing goes, this will cut the steel vertical girders that support the bridge.

4.) Underwater charges under the concrete footing supports go, these give the bridge one last shack to rock things loose, further break what has been cut and weakened, and blow away more of the concrete footers which coupled with the steel supports which have been cut or weakened should be enough to tumble the spans into the water. <Its kind of like chopping a tree, how a logger will notch it before starting on the primary cut, if we can eliminate first foot or so of the support pillars it will fall giving that much more stress on the already weakened structure>

The longest phase of the explosion will be the termite bombs burning, then after about 20 seconds of the thermite cutting, the charges go off in the order they are posted with three to five second intervals.

The danger, one explosion could damage the other charges, this they all need to be in independant systems as well as redundancy.

Anyhow, those are some of the things I'd think of and possibly try.

[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?

[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.