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> Arcology Structural Stability, Umm...that wasn't supposed to happen...
DocMortand
post May 22 2005, 09:36 PM
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Edit: this is from the Arcology Shutdown timeframe.

Due to a slight miscalculation, my most recent mission came to a screeching halt because I threw too many Spiders at the group. The runners dispatched the four (4) spiders in 1 Combat Turn...and due to their explosive nature when compromised, all 4 spiders detonated in the same area - inside a stairwell in one of the main support columns.

4 explosions simultaneously, each doing 12S against what I would determine to be Heavy Structural Materials (16, so 32 against blast damage).

Am I doing the math right? Is the stairwell walls (not to mention the chunky salsa up and down the stairwell) now blown out due to the 48S explosion? How has other people dealt with this sort of thing? At the time, and with much chagrin, I ruled that there was now a spherical hole from floor 34-36 stairwell (epicenter on 35) and many people died from a combination of the explosion and the wall fragments. (Nobody is dead-dead, but the mage took a deadly wound, and now has a Geas that he can't cast without having an open flame. Since he's a pyro at heart, I thought that would be fine...just gotta carry a zippo around)

Other aftereffects (the damage is done now, literally) is would this sort of explosion be detected on seismometers, draw attention to the Arcology (now in Hour 12 of Shutdown) and other effects?

Also, how many support columns would a building like the arcology have? I said more than 4 (since it is a WIDE building), but I ain't a structural engineer so I would have no idea how, where and why supports would be needed.

Help, opinions and general comments welcome. :) *braces for explosions*
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hermit
post May 22 2005, 10:41 PM
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Isn't the Raku Arco almost 1,000 meters high and more than 5 blocks by 5 blocks in base? That would call for a very stable construction, or the building would collapse from it's own weight (and more than 4 major support collumns). the building would propably require many more than four main elevator shafts to handle inner-building traffic! Also, it would require very strong materials. Possibly more than standard heavy structural.
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Aku
post May 22 2005, 10:44 PM
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I'd like to note on the unlikely hood of a stairwell in a support column. It wouldn't happen. Hallowing out something like that, for a stairwell would obviously not provide any support at that point, so a collapse of even a segement of the building shouldnt be possible.
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toturi
post May 22 2005, 10:58 PM
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He could house rule that the material is stronger than standard heavy structural. But I don't think that was the point.

Speaking as a has-been civil structural engineer, you could experience partial collapse depending on which level the explosion occured. But no, the whole building wouldn't collapse if only one main support column was destroyed. However, with an explosion of that scale, (again depending on where you put that explosion), you might end up with a compormised structural integrity and there are nuclear power plants in the arc right? I don't know about Deus but sitting on a nuke plant with compromised integrity isn't going to make me feel safe (shut the damned power plant down).

Aku, yes, IRL, you can put a stairwell in a structural column. I bet you ride in one every day. Just think liftshaft writ large.
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Cray74
post May 22 2005, 11:08 PM
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QUOTE (DocMortand)
Other aftereffects (the damage is done now, literally) is would this sort of explosion be detected on seismometers, draw attention to the Arcology (now in Hour 12 of Shutdown) and other effects?

No, it's not going to set off a seisometer. Just because the power peaked high enough to blow out some walls locally doesn't mean the explosives were actually powerful on an absolute scale - a multi-ton car bomb might be noted on local seismographs, but a few suicidal drones won't be.

QUOTE
Also, how many support columns would a building like the arcology have?  I said more than 4 (since it is a WIDE building), but I ain't a structural engineer so I would have no idea how, where and why supports would be needed.


Depends on the design. The WTC's had major structural members every few few feet around the exterior and major columns in their cores. They managed to survive the mechanical damage of having large sections of one or two sides' structural members blown out.

One support won't matter on the Arcology.
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DocMortand
post May 23 2005, 12:17 AM
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Ah, thanks - didn't know that about the last, either. Makes my life slightly easier...

And yes, Deus is making some changes about now - and learning. :vegm:

Does make me feel better that blowing out a support column wouldn't cause it to collapse - I know the Labyrinth floors basically were gutted during its creation.

Also, I had thought of that during descriptions of the stairwells...they aren't banister stairwells, they are spiral (err, square type) and solid tunnels.

*shrug* Thanks everyone, puts my mind more at ease.

Edit: on second thought - How has GMs out there done blast damage through walls in their games? I.E. the damage blew out the wall - the remainder force hits the people sheltering behind the wall, yes. But what about the fragments of the wall hitting the people at speed?
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Trax
post May 23 2005, 12:26 AM
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And here I thought you or the group had somehow caused the entire thing to collapse. That would've been hilarious.
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DocMortand
post May 23 2005, 12:38 AM
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nonono!

There is now a spherical hole in the middle of the arc, and two floors of rubble strewn about (mostly on top of comatose civilians, to be honest. :) ) The faces of everyone when I drew the sphere on the dry-erase grid was priceless, tho...tho probably not as priceless as my own as I contemplated the idiocy of sending 4 SPIDERS to take out a group of people which included a Troll with a cheap claymore.

The reason the spiders were all in the same place is that he killed 1 per inititive pass...and the last one chased him down the stairs so he used the claymore as a baseball bat and batted it on to the far wall (where the others were). The next 2 combat turns were spent running, because everyone KNEW there was a countdown to explosion. (Experience is a wise teacher)
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Herald of Verjig...
post May 23 2005, 12:53 AM
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QUOTE (DocMortand)
How has GMs out there done blast damage through walls in their games?

In my opinion, the building material should rarely matter in the damage code of the force that gets through. The energy is decreased by the solidity of the wall, and then converted into kinetic energy for the now flying bits of retired wall material. The part I would be most likely to change is the description of the aftermath. However, if the wall material seems especially malicious, I may change the damage effect to be AP or flechette logic, and in extremely rare cases incendiary.
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post May 23 2005, 12:56 AM
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I would say it's a miracle anyone survived having rubble land on them. A small chunk about the size of your fist falling from that height is enough to kill someone. Not to mention other rubble falling is steel, glass, and equipment.

And since i'm a little ignorant of this, isn't the military surrounding the Arcology? Or is that later? At the very least all civilians outside the place would've been evacuated. However, how many civilians INSIDE the arcology was killed by the blast? :D
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DocMortand
post May 23 2005, 01:51 AM
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This is literally 12 hours after the takeover started. According to RA:S the military doesn't get in until a month or so later - it's all police surrounding the building, but for at least 1-2 days nobody knows what's going on and not much is done other than screaming diplomatically at Renraku higher-ups.

I trapped the group in there literally in the Mall at Shutdown, so I had to create the timeline of how people and things are changed from the Shutdown to the result in the floor breakdown in the back of the book. I also had to figure out what outside response would be - and at what stage things change. Time consuming, to say the least. *exhausted grin*

Of course, now with the group creating 2-floor holes in the Arc the timeline is going to get shifted. A lot.

Edit: Casualties: none dead-dead (that the group knows of), but 9 unconscious and bleeding (including 5 civilians that had attached themselves to the group for protection, and the group's mage). The total death count, OOC, is 15 dead-dead, 20 unconscious.
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DocMortand
post May 23 2005, 01:55 AM
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QUOTE (Herald of Verjigorm)
QUOTE (DocMortand)
How has GMs out there done blast damage through walls in their games?

In my opinion, the building material should rarely matter in the damage code of the force that gets through. The energy is decreased by the solidity of the wall, and then converted into kinetic energy for the now flying bits of retired wall material. The part I would be most likely to change is the description of the aftermath. However, if the wall material seems especially malicious, I may change the damage effect to be AP or flechette logic, and in extremely rare cases incendiary.

Yeah, I increased the damage code to D instead of S because they were on the 34th floor, and the people caught in the blast then got smashed by debris that fell on them from the floors above.
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toturi
post May 23 2005, 02:04 AM
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You might have a problem there. 1/3 length/height/width/etc is often the magic number for the max stress envelope . I know that there is no real rules for this, but having an explosion at 1/3 of your height is very dangerous. You could a collapse of more than a couple of floors, the entire sector(that was supported by that column) might just come down. And 1000m worth of a single sector is no joke.
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hobgoblin
post May 23 2005, 02:10 AM
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moral of the story is, never underestimate the effects of explosives in a confined space :silly:
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DocMortand
post May 23 2005, 02:10 AM
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well it was a 18m radius hole (floors are approximately 18m apart (at least that's the number I've been using, and I'm sticking to it in my universe) so I don't think the entire sector would collapse, I think... It's definately weakened and unstable in the area, however.

In any rate, the swarm of spider drones that the group shortly heard after they had limped into hiding would shore up the damage before it got too catastrophic.

How fast would that collapse, assuming it occurs, happen? Again - I'm an audio engineer and musician, structural engineering is NOT my strong point. :)

Edit: hobgoblin - you got that right...If I'm going to send drones at the party they are going to be fewer, and tougher...and supplemented with cannon fodder Blues. ;) Deus has other problems to deal with, however...the runners ain't going anywhere. ;)
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Slacker
post May 23 2005, 02:13 AM
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Depending on just how close the explosion was to the outer edge of the arcology, I wouldn't think the sound of this explosion would carry to the outside, especially if they were near the center.

They were 34 floors up (roughly 100m) and who knows how far in. remember that the arcology would be over 1000m per side. The strength and amount of building material would seriously dampen sound, particularly the dense material of the main support columns.

Also something that size is going to have a heck of a lot of support columns for safety reasons. I could see the areas of floors immediately adjacent to this main support column being a bit unstable. Though, once you get several floors away from the actual blast, the stability should increase as other support columns take up the burden. The structure as a whole should be in no danger whatsoever.
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toturi
post May 23 2005, 02:29 AM
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A couple of days to a couple of minutes of subtle warning signs(small cracks on the walls) that a civil engineer will recognise, then I'd give about 1 combat turn for the place to come down. The thing is that once a building or part of it decides to come down, it comes down very fast.
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Penta
post May 23 2005, 02:36 AM
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Also....Seattle is rainy. Very rainy.

It's December, height of wet season.

If the acid rain is coming down, whaddya think happens to the internals of the Arc?
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Austere Emancipa...
post May 23 2005, 03:03 AM
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QUOTE (DocMortand)
4 explosions simultaneously, each doing 12S against what I would determine to be Heavy Structural Materials (16, so 32 against blast damage).

Am I doing the math right? Is the stairwell walls (not to mention the chunky salsa up and down the stairwell) now blown out due to the 48S explosion?

According to the the basic rules concerning explosions (I'm assuming there's no special rule for several spider drones exploding at the same time), it'd just be 4 separate 12S attacks against the building materials, which does nothing against BR 16 (less than half the adjusted BR). Just like you can't use 4 normal hand grenades to do 40S, 4 spider drones shouldn't do 48S.

Should a blast with a Power of 48 occur, though, Heavy Structural materials still wouldn't be completely blown away. You'd just get through one layer (one set of walls or floors around the blast), the second getting slightly damaged at most. If the walls/floors are far enough away from the blast that the effective Power drops to 32 or less, even the first layer isn't penetrated.

To get an idea of just how huge a Power of 48 is for a blast in SR3, consider the fact that it'd take 256kg (564lbs) of TNT to get to 48D.

(In all fairness, I'm pretty sure I'd just fudge things like this myself without even bothering to check the rules, and if it works for your group then it's all good.)
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DocMortand
post May 23 2005, 04:25 AM
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*nod* Opinions were split both ways. Considering it was in an enclosed space, (thick and chunky salsa rule) I figured the damage would amplify and merge since they did go off simultaenously. I know the stairwell is useless 48m up and down from 35 because of the blast effects that channeled through the path of least resistance.

I think if it were just 4 drones in a room, this wouldn't be an issue, but this was in a stairwell 3m wide and 6m at the landings. *shrug* Even if it were 12S x4, combine that with the rebound waves from all FOUR explosions...I have a feeling the damage actually may be worse that 48S.

Edit: that's why the hole was only 16m radius, not 48...for 16m the walls couldn't withstand the explosion. outside that, the walls are still intact.
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Kagetenshi
post May 23 2005, 05:14 AM
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QUOTE (Cray74)
No, it's not going to set off a seisometer.

Define "set off"? I have little doubt that by 2059 something like this will register on seismometers for miles around, but it'll be ignored the same way as the vibrations registering from construction across town will be ignored.

~J
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Austere Emancipa...
post May 23 2005, 05:40 AM
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QUOTE (DocMortand)
Even if it were 12S x4, combine that with the rebound waves from all FOUR explosions...I have a feeling the damage actually may be worse that 48S.

What was the Blast Rating in question? (-Power/# meters)
At -1/meter, in a 3-meter-square space, assuming the explosion is at the middle of the room, you get to 10.5 + 7.5 + 4.5 + 1.5 = 24S*, tops. This still wouldn't manage more than reducing the BR of the walls by 1 -- or by 4 with all four explosions. The fifth would actually cause a minor breach on two adjacent walls of the room.

*(12 - 1.5) for the first blast wave, (12 - 1.5 - 3) for the first reflection off the opposite wall, (12 - 1.5 - 3 - 3) for the reflection of the first blast wave off of both walls, etc.

Assuming 2.2m high ceilings and detonation on the floor, you could get to 12 + 7.6 + 7.6 + 3.2 + 3.2 = 33.6 against the floor and 9.8 + 9.8 + 5.4 + 5.4 + 1 + 1 = 32.4 against the ceiling, which might cause a minor breach against BR 16. Four explosions might cause a minor collapse of the floor and ceiling around the area of detonation.

What would happen to a stairway according to the rules depends heavily on the architecture of the spot where this occurred and the positions of the drones, etc., so I can't really comment on that. And there'd be no point in doing the math either, because common sense is likely to provide better answers. The only reason I bothered with the math above is because it's 0840hrs, and I'm out of caffeinated drinks and starting to feel bored -- I would not bother with it in an actual game, nor do I expect anyone else to.

This post has been edited by Austere Emancipator: May 23 2005, 05:42 AM
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DocMortand
post May 23 2005, 06:21 AM
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According to RA:S the self-destruct is 12S (in this case...different drones have different powers), -1/m (the power plant detonates...it's not a demo charge)

Location was against the wall, on the floor on one of the landings where the exit to 35 was. Assume 3m (troll didn't have to crouch to run the stairs)from floor to ceiling. What's the math then?

Anyways, my point was why wouldn't the four blast waves combine with the reflections in a chunky salsa effect? If the reflections combine, one would think multiple blast fronts would combine as well.

And yes - at this point you gotta go with what your gut tells you. I can see your point, and I can see this one.

Eitherway, it's a hellacious explosion that severed a support column.

Dunno...one of my runners took my map and figured out just how many columns there are in my version of the arc - 16 total, in a 4x4 arrangement. So...how many do they need to sever to cause catastrophic failure? (yes, they are actually asking this...plus what effects luring 40+ spiders to their doom would be. GAH!)
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Johnnycache
post May 23 2005, 07:26 AM
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How about a safety factor that dictates "flame units only" when the things are in a critical area? That's what I'dve done, either that or not even worried about blowing out the strut. The way I look at the structual aspects, designing the arco presses the limits of current science, much less what I personally know about architecture, and why invite them to worry about it?

Either that or start running a little 'instability tally' based on how much damage they've done to the structure they're running in vs its size.

You could also rule that there was some wave cancellation in the explosion, lessening it 'just enough'
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Austere Emancipa...
post May 23 2005, 10:31 AM
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QUOTE (DocMortand)
Anyways, my point was why wouldn't the four blast waves combine with the reflections in a chunky salsa effect? If the reflections combine, one would think multiple blast fronts would combine as well.

The way I'd reason it to myself is that, in SR3, in order to increase the Power of an explosion 4-fold (12-48) with straight explosives you'd need to increase the amount of explosives 16-fold, plus there're no rules for combining the blasts of separate explosive devices in any other situation, not even in the (very silly) Elemental Fire Secondary Effects.

In any case, the blast reflection rules as written hardly make much sense when applied to situations like this (or most situations in general). What you're basically talking about here are 4 explosive devices only barely more powerful than a basic fragmentation hand grenade (which SR3 wrongly calls "Offensive Hand Grenade" instead of "Defensive") -- with a Blast of -1/m, they're probably supposed to do most of their damage through fragmentation anyway -- and there's an obvious direction for the overpressure to get out through (the stairwell). I wouldn't give something like that a snowflake's chance in hell of demolishing heavy reinforced concrete structures IRL.

This post has been edited by Austere Emancipator: May 23 2005, 10:35 AM
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