----- Original Message ----- From: "Dan Michaels" To: Sent: Friday, September 14, 2001 12:58 PM Subject: Re: [OT]: Structural Collapse - Engineering Debacle ??? > Good - hopefully, these issues will all be reviewed in > public forum in coming months. > > However, the ESB might fail, it certainly wouldn't > pancake 102 floors straight down in 8 seconds. ... after withstanding a 11,000 gallon (assuming a fully fueled 757, a 767 is over twice that amount) jet-fuel fire in it's *mid-section* (HALF the building weight?) for 55 minutes ... Tell me what spec you would like to see here? Perhaps *twice* the amount of fire-proof cladding should be applied to the structural steel from, say the half-way (or higher) point down? Perhaps new materials and a staggered application should be now considered? Jim > > > > At 01:03 AM 9/13/01 -0500, you wrote: > >What's the relative cost? Will the extra > >material balloon the costs? > > > >What about labor the labor/time, cumulative > >for 110 stories worth - > > > >- or was this for just to locations/floors, > >as proposed earlier - which I don't think > >that's practical to stop a series of floors cascading/pancaking down on each > >other? > > > >Does the extra material *really* contribute > >anything except when *deep* into a failure > >scenario? > > > >The original design (as freely quoted here) > >called for 2 hours worth of fire exposure/duration - > >giving enough time to evacuate - should the specs > >be rewritten to now mandate that the building > >*NOT* collaspse due to fire - in light of all > >the collateral damage that occurred? > > > >Will the extra material contribute excessively > >to weight? > > > >Jim > > > > > > > >----- Original Message ----- > >From: "Dan Michaels" > >To: > >Sent: Thursday, September 13, 2001 12:35 AM > >Subject: Re: [OT]: Structural Collapse - Engineering Debacle ??? > > > > > >> jvpoll wrote: > >> > "One would think that adding heavy cross > >> > members every 20 floors or so might > >> > prevent the entire structure from > >> > pancaking like that" > >> > > >> >I wonder what the 'load' of oh, say, what? ten > >> >stories is as it collapses down upon the next > >> >story ... isn't that **the new load** that > >> >that the floor space *then* needs to support - > >> >- the full ten stories that just came down? Not > >> >to mention the inertial effects that the mass > >> >of ten stories has gained in ten feet (or more) > >> >of distance ... > >> > > >> >As it was, I am assuming that the vertical support > >> >steel structural members (both external, along > >> >the external walls and internal) *failed* on > >> >one story initially - > >> > > >> > >> This ???? > >> +----------------+ > >> | | > >> | | > >> | +----+ | > >> | | | | > >> | | | | > >> | +----+ | > >> | | > >> | | > >> +----------------+ > >> > >> or this ???? > >> +-----+----+-----+ > >> | \ | | / | > >> | \ | | / | > >> +-----+----+-----+ > >> | | | | > >> | | | | > >> +-----+----+-----+ > >> | / | | \ | > >> | / | | \ | > >> +-----+----+-----+ > >> > >> Which is gonna do better? Which is more likely to > >> have the broken part crash "outwards", sparing > >> the floors below? Which is more likely to come down > >> 110 stories like an elevator down an empty shaft? > >> > >> -- > >> http://www.piclist.com hint: To leave the PICList > >> mailto:piclist-unsubscribe-request@mitvma.mit.edu > >> > >> > > > >-- > >http://www.piclist.com hint: PICList Posts must start with ONE topic: > >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > > > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body