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Old 07-08-2015, 02:38 PM
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Webstral Webstral is offline
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The fate of the bridges is a valid concern. The first issue is whether a given bridge will be left standing after a specific nuclear attack. The second is the degree of impact the bridge will have on navigation.

The Benicia-Martinez Bridge will be affected by 500kt airbursts directed against targets in Benicia, Martinez, and Avon. Unless I have put the Martinez epicenter too far south, none of the 20psi rings from the Benicia, Martinez, and Avon blasts overlap the bridge. All of the 5psi rings overlap at least part of the bridge. Assuming for the moment that the Soviet strikes were very accurate (not a reliable assumption, but we’ll deal with one variable at a time), then the bridge is subjected to 3 separate overpressure waves sufficient to cause most residential buildings to collapse. We should bear in mind that residential buildings are very different structures from large bridges. Wood and even brick houses are flimsy compared to steel bridges meant to carry bumper-to-bumper 40-ton tractor trailers, if need be. Bridges are designed to withstand vertical compression, which is what an overpressure wave from an airburst at 2.5km will generate against this target, albeit at roughly a 30 degree angle. The Avon strike places the most horizontal stress on the bridge. However, this strike is the furthest from the bridge. The 5psi ring only covers the southern half of the bridge. Bay Area bridges are designed to withstand earthquakes: i.e., very significant vertical and horizontal stress. So while the cities nearby and the toll plazas might be knocked down, the Benicia-Martinez Bridge probably won’t be destroyed by the canon strikes nearby.

The Richmond Bridge is a different issue. The 20psi ring overlaps the 2km length nearest the Richmond end of the bridge. If the detonation is an airburst roughly over the center of the refinery complex at 2km, the easternmost section of the bridge probably is going into the water. How far west the collapse extends is unknown. If a span of the bridge falls into the middle of the shipping channel while attached on the western side, there’s definitely going to be a navigational hazard. If the bridge stays up over the shipping channel, there shouldn’t be a problem. If the bridge drops a span completely into the shipping channel, the extent of the navigational hazard is hard to forecast. Ocean-going (deep draft) vessels might not be able to get through, but shallow draft barges and smaller craft might be unaffected. It’s hard to say.

While I cannot fault anyone for sticking to the published materials, which state that Richmond is subjected to a 1.5Mt airburst, I remain committed to the idea that an alternative explanation ought to be explored. A 1.5Mt airburst against Richmond is virtually the equivalent of a nuclear attack on Oakland and San Francisco. If the target really is the refinery, then an airburst of this magnitude in this location runs the risk of having the Americans conclude that the exchange has moved into the city-busting phase. There is great room for latitude here, since the Richmond strike clearly is out of step with the other three strikes against Bay Area refineries. Something unusual is happening here, since logically all four targets should be hit at once with warheads of similar yield. A great many explanations may be offered for the distinctiveness of the Richmond attack. I offer the ground burst model mentioned in a previous post as one means of sticking to the idea of a limited exchange focused on important economic and industrial targets but not on flat-out city-busting.

Another possible explanation for the 1.5Mt strike that also gets around the city-busting challenge is an attack that is deliberately off-target. For instance, an airburst centered 7km north-northwest of the center of the refinery complex includes the complex in the 5psi ring as well as the thermal radiation ring. It’s not hard to imagine fires destroying the complex. Richmond and San Pablo are doomed, but Oakland and San Francisco are far enough away that they are not obviously targets of the attack.

Now that I am looking at this model, I like it better than the ground burst. Fallout got mentioned above. I looked at the fallout model again, and it really does look like Fairfield and Sacramento get destroyed by fallout. Since Sixth US Army is listed as controlling an area anchored on Sacramento-Oakland, and since that very area gets hammered really hard in a 1.5Mt ground burst model, I think I’m going to have to abandon the ground burst model. Too bad. I worked hard on that.
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