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Re: Hundreds Of Calif. Hospitals At Risk Of Collapse[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: <seaint(--nospam--at)seaint.org>
- Subject: Re: Hundreds Of Calif. Hospitals At Risk Of Collapse
- From: "h.d.richardson" <h.d.richardson(--nospam--at)shaw.ca>
- Date: Wed, 26 May 2010 14:33:17 -0600
Conrad,This is quite a dissertation, Conrad. It's a bit long; but I'm glad you took the time to write it. It expresses some interesting ideas that are worth thinking about.
Regards, H. Daryl Richardson----- Original Message ----- From: "Conrad Harrison" <sch.tectonic(--nospam--at)bigpond.com>
To: <seaint(--nospam--at)seaint.org> Sent: Tuesday, May 25, 2010 11:40 PM Subject: RE: Hundreds Of Calif. Hospitals At Risk Of Collapse
So the buildings have been serviceable for 39 years. What is the point of retrofitting them, and misleading the people into believing the buildingsare safe? Codes are crazy: stronger doesn't make it safer. Start with persongetting crushed by 1 ton concrete panel, get paranoid, make stronger, nextbig event several people get crushed by 10 ton concrete panel. Sure made itsafer. The acceptable load is a matter of subjective opinion, dreamed up by the code writers: a matter of fiction. What ever it is, there is always the probability that it can be exceeded. When it is exceeded then life is indanger. It is how the structure behaves and responds to the load, and how itcollapses and what hazard it creates after the collapse that is more important. More sensible than running around tell everyone we can stop the building from collapsing. The buildings are going to collapse: full stop: nothing we can do about it.The owners expend the money on retrofitting, and the next big event exceeds the design load: the hospitals collapse any way. But now no money to replacethe hospitals. Seems like a more sensible risk analysis needs to be conducted than simply upgrade all the hospitals. Our task is largely to maximise the benefitobtained from the available but otherwise limited resources. We cannot keepusing more and more resources to construct a single building. Take the Chinese earthquake, if had Mongolian yurts rather than concreteapartment blocks, then a few people may have got tangled up and suffocated, but few would have been crushed or buried, and recovery would have also been much more rapid. Damage to the materials would not have been permanent: thatis structures may have collapsed: but stand them back up again after the event.It is not just a matter of whether we can survive the environmental hazard,but how quickly we can recover after the event, and how we respond during.How do people get to the hospital? And how do supplies get to the hospital?And the housing has that all been upgraded? How certain can we be that all systems in a region will fail at the same event and no sooner, and asexpected? That is all houses have collapsed and all post-disaster facilitiesremain fully operational: and the region can recover on its own with out external assistance. Codes seem to be based on a vague notion, and there is no code which defines a rigorous assessment of what should or should not go into a code. Take the Australian codes: they are semi-probabilistic. But there is no clear separation between the hazard to life, the loss of amenity and the economic loss. A building can be maintained and remain operational beyondits expected economic life. If not operational the building may still remainin the environment. Rural and industrial buildings in particular. Ruralbuildings tend to have lower design loads because in remote areas. Secondlyhouses and other normal importance buildings are not expected to provide shelter from extreme environmental hazards: nor remain serviceable after such events. The primary objective is to minimise injury resulting fromultimate failure: the deemed-to-satisfy provisions of the code achieve this be adopting high loads with a low probability of being exceeded. Alternative approaches are permitted as long as the fundamental performance criteria are met: which at its simplest is that the structure be sufficient for purpose.Those willing to can step outside the structural codes because they are not mandatory, only deemed-to-satisfy: and so seek more innovation solutions oncondition they can provide adequate evidence-of-suitability. That is they can adopt an approach using the risk management standards, which are not called up by the Building Code of Australia (BCA): and thus present and demonstrate suitability of what the BCA calls an alternate-solution. I therefore would take it that if the hospitals are reviewed on a case bycase basis, then after 39 years, some of the buildings are close to the end of their economic life. And if US TV shows are anything to go by, then somehospitals have more immediate building and other issues to resolve: than whether the building will survive some possible future earthquake. Forexample larger hospital with more medical staff required. Heritage can be abenefit and an hindrance.Industry can find spare land overseas to build a new hi-tech factory. It can then demolish original factory and build a still more efficient factory. Sothat at any point in time have one factory operating and another being constructed or fitted-out. But a hospital generally cannot be relocated. So once got a hospital generally stuck with it. That poses a problem for sustaining its operation in the long term. Manufacturing wise maximum efficiency is typicallyachieved if only operate at 90% of capacity: the remaining capacity is part in planned maintenance or in reserve as emergency stand by. If don't do this can have a high risk of losing significantly greater proportion of capacity. Bean counters don't like this however, they want to operate at 100% capacityand beyond to push growth. But growth seldom adequate to justify expansion of facilities: so tend to operate overloaded on the brink of disaster. Hospitals are no different. If hospitals have spare beds, then no justification for building new hospitals. New hospitals only built, whenexcess demand is considered to be permanent. Profitable industry it may be,but profits don't measure whether it is an effective, sustainable and quality service provider.The buildings and other infrastructure we have, our heritage, are taken forgranted. We can build upon our heritage but it is not always suitablefoundation for the future. Its like solving Rubics cube: have to mess it upto move forward. We have disasters because we fail to accept a more evolutionary short term inconvenience. It is also like the example of thefrog. Throw into scolding water and it will immediately jump out, put it inwarm water and slowly bring to the boil and the frog will stay there and boil to death. Humans are the same: they become complacent. Fatigue is an accumulate phenomenon. So building survives one or moreearthquakes or hurricanes, building looks perfectly fine and people start to assume can occupy the building safely during and extreme event: but the nextevent is minor and reaches the fatigue limit of the material and disaster ensues: and everyone is wondering why.I believe it is better to accept that nature is all powerful, and its forcesare far too great and impractical for us to resist: most especially as individuals. Better to learn to flow and ride with the forces, than toresist. I mean, there is a 2 metre wide crack in the ground outside: but noworries the building will stitch the ground together: I doubt. Ok! Most of the time it is just vibration. But that's the point, its just vibration,the building resists, so no worries, and become complacent: and not preparedfor the aftermath of failure event. By increasing the resistance, we displace the failure event to some more distant future date: we do not eliminate the failure event. In doing so failure is not perceived as an eventuality, and preparation for is neglected. Can have a perfectly sterile environment and live in such, but the introduction of a minor bug and the population can be wiped out. By having less than sterile, have the potential to develop own resistance external bugs which may ultimately invade. In similar manner it is the individuals ability to respond to the hazardwhich matters, not the resistance of the buildings. If already in a hospital at time of an extreme event then already at a disadvantage. At the ultimateevent the hospital will fail, and the hospitalised are dependent on others to get them out, and those injured are dependent on how quickly fieldhospitals can be setup, and where such can be set up. The design event is aninconvenience, the ultimate event exceeds the design event and becomes a disaster if individuals and emergency services are not able to respond appropriately. The optimum solution therefore is a balance between our ability to respondand provide services and recover from destructive forces versus our abilityto resist those destructive forces. Optimum solutions are typically onlyvalid at a given point in time and for a small range of variation. A qualityrobust solution is valid over a much greater range of variability. I believe our current approach is displaced from optimum and not qualityrobust, and is far too biased towards resisting the great forces of nature. On top of which the public face of engineering, tends to con the public into believing we can resist those forces. Like the medical scientists, one week something is good for us, the next it causes cancer, the next week its goodagain: basically they have no idea and appalling knowledge of statistics: but it fills a news slot arguing one way and then the other. Likewise whether or not our buildings can resist earthquakes. The last destructive earthquake Adelaide experienced was in 1954, so apparently we don't have earthquakes nor hurricanes or other storms: builders tell me so regularly. The last earth tremor I experienced here in Adelaide, was about a week after the Chilean earthquake, prior to that around the early 1980's. Whilst storm damage occurs to buildings at around90km/hr to 110km/hr every year, yet regional design wind speed is 162km/hr.Cyclone Larry demonstrated that older buildings pose a risk to new buildings. We could go to the expense of upgrading all existing buildings,on the other hand they are our heritage, they have survived thus far. So dowe really need to be constructing newer buildings for greater loadconditions? Besides the BCA is revised each and every year: so that would be a programme of continuous upgrade to meet current codes. Revision generallyclarifying meaning and intent: which implies some approved buildings have not met the objectives. Which suggests that maybe go modify last years buildings, not quite meeting the objectives, to meet the clarification inthis years code. Keep people in the building industry employed at any rate.Short of work raise panic, all for the good of public safety. But really it's a con, no one is improving public safety, just increasing theresistance and cost of the structure. And the cost of future reconstruction: and ignoring money, it simply means more resources required to provide lessamenity. For example materials that could have provided two hospitals now can only provide one hospital, when we need four hospitals. Not exactly maximising the benefit from the available but otherwise limited resources:which is fundamentally the role of engineering. Scarce resources how can we best use them? Just about any technician can size the beams to the code: but are there any real engineers with the imagination and ingenuity to go beyond the self-imposed constraints of the codes and solve the real problems ratherthan apply the known solutions? Put simply when the hospitals have been upgraded and strengthened: thehospitals will be at risk of collapse. The risk maybe lower, but it is still there. So what is the point? Accept the risk you have and prepare to respond accordingly to the failure event not some arbitrary design event. After all,lucky the failure event has not occurred already, and need to be lucky it does not occur before the upgrade is complete, and then need to be lucky that the design load is not exceeded too soon after the upgrade. That is a lot of luck to try and hide behind science. Regards Conrad Harrison B.Tech (mfg & mech), MIIE, gradTIEAust mailto:sch.tectonic(--nospam--at)bigpond.com Adelaide South Australia ******* ****** ******* ******** ******* ******* ******* *** * Read list FAQ at: http://www.seaint.org/list_FAQ.asp * * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to: * * http://www.seaint.org/sealist1.asp * * Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********
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