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Re: Architect cheating on structural calculations - where's the building depa...

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On Dec 7, 2005, at 10:41 AM, Paul Feather wrote:

A plan checker cannot be expected to catch errors on a complex project in a few short hours when that project has taken months to design, unless those errors are blatant.  If a jurisdiction truly wants to have a structural plan check, anything less than peer review by competent equally licensed individuals will be flawed.  A system where authority is given without accountability is prone to abuse.
For cultural value, the meaning of checking and reviewing is universal. I don't think anyone these days really knows what it's supposed to do. At one time it meant looking over design drawings for things like tolerance stack-up and dimensioning errors. Later when design incorporated a significant amount of math analysis it included someone to check arithmetic. It really should incorporate a run-through of the design rationale from assumptions about service conditions to the use of sound practice and prudent assumptions.

In 40+ years of engineering practice, I've never seen a design review that really did that. I've seen a lot of so-called reviews that amounted to checking arithmetic--checking that Mc/I was calculated correctly but not whether the assumption that the item really behaved like a cantilever beam was accurate or prudent. God knows how many reports I've submitted where I was gigged for word usage but got no questions whatever on my approach. The charming part is that most of the comments on word usage were mis-informed and I ended up finding numerical errors like mis-placed tabular data on my own when I was fixing an incorrect subscript.

My own experience in the nuclear power business, where a lot of attention is paid to checking and verification, is that most such requirements are nonsense. Most are procedural: fill out the right forms or include enough signature blocks and you pass the audit. Verify FEA software with a couple of trivial problems and you're good to go for non-linear seismic response. I had a guy 'audit' an analysis by spending two days leafing through a stack of computer print-out without the slightest expression of interest in how I'd set up the analysis. Same for aerospace projects. I had one reviewer demand that material for a platinum-iridium sensor element be covered by an ASTM spec. At the other end of the spectrum comes fracture reviews by people who can't interpret analysis results--they just make sure the box is checked off.

Oddly enough it's the little things and the fundamentals that always get you--the stuff that never gets checked because it's too simple or too obvious. The best plan checking system I've ever seen has come from drafters or shop people with experience on similar projects and the initiative to ask me about something that doesn't look familiar. For a sprog engineer, answering a lot of questions that might be obvious seems like a big pain in the ass, until one day someone bails you out big-time by finding something you forgot.

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw(--nospam--at)   | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania 1864)

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