John Scarry Engineering - Canterbury Earthquakes Royal ...

ENG.SCA.0002.RED.46
276. Given that assumption, how could the GNS people on that committee then impose the
‘El Centro’ shaped response spectra curves for Christchurch, when the very deep layers
of alluvial deposits made response spectra curves more like ‘Mexico City 1985’ much
more applicable?
277. These erroneous assumptions, overlooking a report that had to be proved incorrect to be
ignored, meant that the horizontal earthquake coefficients for taller, longer period
structures were massively underestimated, and reduced significantly from NZS
4203:1984. At a first period of 2.8 seconds, because the Hotel Grand Chancellor was
designed to NZS 4203:1984, the 22 February 2011 earthquake was exactly a ‘code level
event’ for that building.
278. As if that was not enough, in AS/NZS 1170.5:2004, the ‘seismicity experts’ on the
Standards NZ committee proceeded to further reduce the design base shear coefficients
for taller, long period Christchurch structures designed to be limited ductile (=3) or
fully ductile (=6) by about an additional 25%! (Refer Appendix in my submission on
GEN.CERC.0003).
279. How could Standards NZ allow the completely error riddled structural timber standard
NZS 3603:1993 to be released, then never updated for the next 19 years, other than to
change the allowable timber stresses to reflect the weaker and softer modern Radiata
Pine?
280. Leaving the murky disaster of untreated timber alone, how could Standards NZ allow a
committee to be formed that removed from the non-specific light timber framing
standard (which is used for most house construction in NZ) NZS 3604:1999 the absolute
requirement for a damp proof course (DPC) to be installed under all internal timber
(more than 300mm away from the exterior) in contact with concrete or masonry?
281. How could Standards NZ have allowed a committee to be formed for NZS 3101:1995
that deliberately ignored my submission on precast floor units, when the detail I asked to
be made mandatory was eventually adopted over a decade later, at least for hollowcore,
after the construction of many hundreds of unnecessarily deficient buildings in the
meantime?
282. Given the ‘industry wide expertise’ on this committee, how is it that it either ignored or
did not know about the very significant effect that rate of loading has on the crack
patterns and hence ductility demands on reinforcing bars in seismic resistant reinforced
concrete structures? This is the critical issue as to whether reinforced concrete is
suitable for seismic resistant structures, other than low squat structures. The NZS
3101:2006 committee did not appear to address this either.
283. How could Standards NZ have allowed the complete and utter debacle that was the
drafting of the combined Australia/New Zealand concrete reinforcing standard AS/NZS
4671:2001, and the introduction of Grade 500E reinforcing into the NZ ‘marketplace?’
This absolute disaster still blights the industry. It should have been addressed
immediately, but Standards NZ did nothing. What is worse, nearly all of the ‘leaders’ of
the profession and the industry have treated this rubbish as ‘the writ of God.’ It should
have been thrown out and rewritten over a weekend ; instead, it still blights us, with no
salvation in sight.
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