To: "INTERNET:seaint(--nospam--at)seaint.org" <seaint(--nospam--at)seaint.org>
Subject: RE: effective length factor for sway moment frames? K for frames wit h partially restrained connections?
From: Mark Gilligan <MarkKGilligan(--nospam--at)compuserve.com>
Date: Fri, 30 Mar 2001 11:00:23 -0500
The author of the following response implies that because we have computer
access we should compute the K factor using the computer.
I would like to suggest that such practices often take longer than quicker
but less exact methods. On numerous ocassions I have seen engineers spend
considerable time creating spread sheets to perform a calculation that
could be done quicker by hand.
Given limited design fees and a limited schedule how exact should our
Similarly how much effort should we spend to reduce construction costs
when the fee is limited?
Have computers in many instances actually increased our work load?
>>>Theoretical results satisfy all the governing conditions. The
factor is theoretical exact. They are more reliable than the ones from
alignment charts. Those alignment charts were introduced before computer.
For the time being, almost every structural engineer has a computer for
analysis. Why should we keep applying those inaccurate charts?
When computers were not available for most structural engineers, engineers
used some approximate methods, for example, two cycles, to analyze frame
structures. No one uses two cycles since computer is everywhere. All the
results are theoretically analyzed on computers. FEA of K factors is a