Much as I hate to provide a link to a satirical site in regards to what happened, it does have an image of a LP porch party.
http://www.lptrixie.com/images/pictures/0929-3.gif
Friends living in Chicago tell me that porch parties are VERY common in Lincoln Park.
Pretty common all over the city, really - just that the ones in Lincoln Park and other hot-spots for young types tend to be more crowded and rowdy.
And they’re all painted/weathered to that same slate grey color.
People treat those spaces like a continuation of their apartment - furniture, BBQ’s, bicycles, appliances, storage bins. Irritates the fire department because they ARE intended as your emergency exit and you need to keep a clear path.
Espeically in buildings with no or inadequate air conditioning, a lot of city summer life happens on the back porch. Heck if it gets REALLY hot folks will even start sleeping out there 'cause it’s cooler (assuming the neighborhood allows for it)
I am getting a little tired of the constant coverage. I mean, it’s a tragedy but surely there are other things going on in the world, too, aren’t there?
Looks like the city is trying to find a scapegoat and is gunning for the building owner. And they wonder why folks don’t want to do business in Chicago… There were just too damn many people in one spot, but there’s no use suing the dead because you can’t get money from them.
(I’ve gotten soooo cynical lately…)
Not to pick on Broomstick, but I happen to have a copy of the Chicago Building Code right here on my desk, and the minimum live load for either residential balconies or fire stairs (the porches could be classified as either) is 100 pounds per square foot. No link as it’s available in dead tree format only.
Think about that for a minute. I weigh under 200 pounds and I generally take up between two and three square feet of floor at a party, even when things are packed. 100 psf is the load used for any situation where there’s the possibility of panicked people packed into a small area trying to flee danger (like a fire). It would be very difficult to achieve this at a typical porch party. Therefore, it is reasonable to think that the structure was likely faulty in some way.
The City undoubtedly knows this, but is likely dragging its feet until there’s some hard bit of evidence to point to. The City’s other problem is that there are thousands of these things out there, and I’d guess that a lot of them were build under similar circumstances (no permit, no inspection, no engineering).
Is it just me ro doesn’t it strik you as odd that the structure meant as a fire escape is itself flammable? 
BMalion: I suppose so, but if your fire escape and your usual route into/out of the apartment are both burning, you’re pretty screwed regardless - one can probably assume that your apartment is also engulfed by then.
Finite Elephant - an article (sorry, free registration required) in the Chicago Tribune today features a builder who claims that the building codes are unclear on how these balconies are to be constructed. Apparently there are a few different methods used to build them, as well, with debate over which is the best. I don’t recall (I’d read the print version) if pounds per square foot was mentioned.
Ferret Herder - The code does not provide enough information to construct a deck, that is, it doesn’t say “use a board this big” and “use this many bolts.” It does, however provide enough criteria so that an engineer or architect can design one. There also isn’t a chapter entitled “How to Build the Sears Tower.”
The problem with these decks is that nobody’s engineering them. The builder just builds it the way he/she’s done it for years.
No, I disagree.
Add in a couple beer kegs (stacked), and pack the porch with people you get a much bigger load per square foot than normal. If you took the link to the picture earlier in this thread you see a typical situation - that’s much closer than people would normally stand to each other.
In past porch collapses I don’t think defective workmanship or materials has been the over-riding factor. It really is too many people in one spot more often than not. Well, maybe they should up the minimum load to 200 psf… or make the decks too narrow for a party. Part of the problem is extending those back stairs into a genuine porch without changing how they’re built.
Despite the lack of a permit (according to City Hall - for all we know, there a copy in a file somewhere at the builder’s or owner’s office) I suspect the porch met or exceeded code.
Of course, since the city knocked down the porch and carted away the rubble there is no way for anyone to investigate it and no one for the accused builder and owner to gather evidence to defend themself against charges of neglience. Neat, huh?
Oh? I thought the city carted all the evidence away.
The porch construction techniques are as much tradition as formal engineering - the basic designs date back to the 1800’s.
However, the collapsed porch WAS inspected - because of commercial property at street level the entire building was inspected yearly, including the back porch, and raised no red flags or code violations.
As for permits… as I said, the City can’t locate a copy, but the owner (who is out of communication on a backwoods vacation in Canada until tomorrow {boy, is HE going to have a shock when he calls home!}) and the builder, who is in the hospital receiving cancer treatment, have not had a chance to look for a copy of their own. Until THEY fail to produce a copy I won’t say there is none.
Yeah, it is a little strange. But it only has to last long enough for you to reach the ground. Over a certain height, the escape has to be metal.
According to reports, the party was breaking up because the beer had run out. I admit that stacked kegs could exceed 100 psf, but a unstacked kegs will not. A standard half-barrel weighs about 170 pounds and is 20" in diameter. Add 20 pounds for ice, and you’re at 72 psf.
Most of the reports I’ve seen say that there were 80 people on the deck at the time of the collapse and that the deck was approximately 40’ by 12’. Even if the 80 people were standing around in half the deck (240 sf) and weighed an average of 200 pounds a piece, it still only works out to 67 psf. That’s with each person taking up three square feet. That’s people standing with about 3-4 inches clear between bodies. That’s a friendly party.
What reports are you talking about?
Haven’t heard anything about whether the kegs were stacked or not - but probably were.
The deck was 11 x 16 - much smaller than your 40 x12 (the additional footage might have been occupied by a stairway, but the actual flat deck was only 16 feet long)
So the area was 176 sq feet. 80 people at (average) 200 lbs is 16,000 lbs, or 90 lbs per square foot just of people, and only 2.2 square foot per person. Now add in several beer kegs. Changes the equation considerably. You’re right on the edge of the maximum load limit.