Posts by Fooman
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Hard News: What Now?, in reply to Raffe Smith,
Incidentally, the forthcoming revision of NZS3604:2011 (timber framed building standard) places Christchurch in zone 2 for earthquake bracing requirements. Wellington is zone 3, while zone 4 straddles the southern alps and the plate boundary. Any structural engineers about who could illuminate this?
Cavet: Engineer, not structural, but I taught some structural engineering (to NZS3404 - steel structures) as part of a mechanical design course at CPIT, many years ago. So please forgive inaccuracies from the passage of time.
The NZ design standards are reasonably basic. They work on the basis of working out the load on the initial design, and then comparing them to the specified load carrying capacity of the beams/structural elements used. The loads are based on self weight, capacity (i.e. what the building has to carry, other than itself), wind loading and earthquake loading. Wind loading is based on the effective "sail" area of the building, and the expected wind velocities assigned to a region. Similarly, the earthquake loading is based on the weight of the structure and the expected acceleration from an earthquake in a region, expressed as a fraction or percentage of weight.
These loadings are then applied to the detail of the structure, e.g. prevention of localised buckling by additional webs, load transfer across structures, bracing, and the whole design is checked again to see if any changes in the structure still fit the requirements of the standard. The factors of safety are built into the specified load capacity of the standard beams and the zonal loads.
Based on the unprecedented peak ground acceleration and previously unknown faultlines (from both the Sept and Feb earthquakes), these zonal load factors may be reviewed, and the boundaries changed (i.e. CHCH may be zone 3 from now on).
I can only presume that NZS3406 works in a similar manner - I suspect is is more conservative (due to wider scatter in the properties of the building material and wider scatter in the skills of the people designing and building such structures), but the I think the loadings would be worked out in a similar manner.
hope this helps,
FMCheers,
FM -
Hard News: Again: Is everyone okay?, in reply to Ross Mason,
Thanks for that Ross.
Not being able to concentrate on work too much over the past couple of days. Lived there for 12 years (the middle third of my life, I have just realised). It seems like a long time ago. Trying to work out where everything is or was.
Hope nobody minds me crunching some numbers – it is what I do. Using the raw data from GNS, it seems as though on February 22, the CBD saw 2 or 3 times the peak ground acceleration compared with September 4. A rapid drop off with distance, compared to larger, deeper September 4 event. Cavets of course – I am not a geologist.
+1 for those bringing the attention onto the building codes with respect to strengthening and lack of effective compliance. It is too probably late, except maybe for a very lucky few in Chch. But what about next time? Growing up in the 80’s and 90’s, I often got/get the impression that NZ has a parsimonious culture driven by short term costs, rather than long term benefits. What will be the long term outcome of this?
Deep in thought,
FM -
Obviously things must change to improve, so the the beatings will actually increase, until moral improves.
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Eve Online. Only the Icelanders could come up with something that looks so nice, but is so unbelievably boring.
Eve Online may not necessarily be native to Iceland...
~~wavy lines of faded memories~~
Many years ago, in a small terminal room in the UoC engineering building, I spent many a hour/day on MUD's playing and coding. One of my fellow X-terminal (good for gopher and this new Mosaic app) dwellers was an admin on Discworld MUD. This led to a job offer to develop code for Eve Online, as it would become. In conversation he mentioned that the reason for Iceland* was geographical. It sat on the (then) major bandwidth pipe between the US and Europe - a (or the?) reason for Iceland was simply trying to maximise bandwith and response to those major markets.
~~end wavy lines~~
I await the cool story plaudits.
Cheers,
FM*was still in Iceland 10 years later as far as I know, but he had left CCP
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I was going to post earlier, with an analogy from my own experience (friends with BFA's - one has a career as an artist, one is an artist with a job - there has to be a desire or motivation to run a business if you want to make (reliable) money from self-realised creativity), but all this talk about Amazon print on demand reminds me of a recent article on Neatorama (read and be amazed/despaired):
Precis: Using data mining algorithms, man with receding hairline writes 600 page books for 23 cents each, sells them for a lot more.
As an anonymous former postgrad at UoC, I know Dr Haywood has the brains; does he have the hairstyle?
Cheers,
FM -
From the Eruptions volcano blog (bloody good blog) came:
which is a good ripping technical discussion of the earthquake. Followed it to:
which has a, er, interesting discussion on the sociology of earthquake struck NZ compared to earthquake struck Haiti. Is pointed out in the comments (by Peter Metcalfe - is nz.general still around?) that the Haitian earthquake was considered more destructive by the USGS as the Haitian building standards are (were?) lower.
Cheers,
FM -
One thing that made me swear at Banks on the radio this morning was him describing Great Barrier as a pristine, unspoiled gem in the Hauraki gulf. Never mind that it was deforested, along with 99% of the kauri forests of Auckland and Northland, in the wood rush of the late 19th and early 20th century. Most of the existing forest is regenerating bush. Nice to have no mining on, but certainly not unspoiled and pristine. Ignorant goblin.