28 Mar

To minimum or not to minimum, that is the question?

Minimum steel, love it or hate it, we have minimums for a reason even if it seems like overkill sometimes given that we may have very low demands.

This post will demonstrate why (I hope) we are required to comply with these arbitrary limits. Usually I’m going into these posts with only the theoretical background of why something exists, but hopefully once we get into it this theory can actually be demonstrated.

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29 Feb

Using Mathematica to save the world

Well, one person’s world of torsion anyway…

In this post I’ll show how to use Mathematica to check some derivatives of torsion relationships.

Mathematica is an analysis/computational tool by Wolfram. Now if you had to pony up the dollars for it you’d be out a few thousand dollars, but as it happens I’m cheap and it’s free on Raspberry Pi’s Raspbian operating system. Yes it’s linux based, but don’t let that turn you off, it’s so simple to setup anyone could do it.

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01 Feb

Rational Buckling Analyses to AS4100 or NZS3404 (Part 5)

So if you’ve been following along with this series you now hopefully know a little bit more about some of the methods involved in undertaking buckling analyses. Pat yourself on the back for making it this far through my ramblings I guess (if nothing else).

It’s pretty simple, and in most cases it will yield a capacity very similar to the code hand methods, albeit via a completely different path. It’s always good when different methods yield similar results.

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25 Nov

Rational Buckling Analyses to AS4100 or NZS3404 (Part 3)

In the last post in this series we looked at a semi-real scenario where a rational elastic buckling analysis was undertaken in which we were able to determine the axial capacity of a system of members. The exact type of system of columns is sometimes referred to as a ‘lean-on’ system, whereby the column carrying no load helps to increase the capacity of the supported column. Basically, if we make the supporting column (or in other words the bracing system for the RHS) stiff enough it has the effect of producing a higher mode of buckling in the supported RHS column.

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24 Nov

Rational Buckling Analyses to AS4100 or NZS3404 (Part 2)

In part 1 of this series we briefly explored the requirements related to calculating the capacity of a column via the use of a buckling analysis. Introducing the general methodology to follow and showing agreement with the normal hand methods for a known k_e.

In this follow-up post we look at the power and beauty of this method in being able to assess any complicated design scenario, typically ones that don’t fit in the mould of the typical idealised restraints.

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20 Nov

Rational Buckling Analyses to AS4100 or NZS3404 (Part 1)

This post was inspired by a rather epic post at Eng-Tips forum, which came out of a seemingly simple request for some help on the segment length to consider for a continuous beam design to AS4100 (the Australian Steel code). Fast forward several hundred posts of debating issues of code interpretation, debates over critical flange definitions, everyone telling each other everyone else is wrong, backtracking, changing of minds, notionally proposing re-writing code clauses to suit particular sides of the argument, etc, etc. At the the end of it all there may or may not have been any real agreement reached, not unusual once engineers get to arguing.

You know when the original poster bows out at post #11, and the thread carries on for 200+ more posts that it’s a hot potato and there’s going to be a few virtual knife fights going down before it’s all said and done.

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21 Aug

Inflection point != point of restraint

It’s a question that seems to come up from time to time in my experience, can you take the point of inflection as a point of lateral restraint for the restraint of structural steel members under flexural forces?

The answer is of course… NO!

Let me say that again… NO, NO, NO!

Some people don’t ask obviously before doing, they just do it and are none the wiser.

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15 Aug

Improving Excels spellchecker with highlighting

Excel does many things well, but it goes without saying many things could be vastly improved, or at the very least shown a bit of love by Microsoft.

One particular thing in Excel that that causes me some frustration is Excels inbuilt spellchecker.

Why? Because it’s infinitely more shit than the spellchecker in any of the other office products for a start.

This personal view is primarily born out of using Excel for the purposes of recording text based queries and responses as part of structural peer reviews. I use it as a log of sorts to log questions, responses and the like. The tabular nature of Excel lends itself to this application.

I’ve had logs that stretch to 40 odd A3 sized sheets full of queries when stuff goes a bit pear shaped and the designer has a ‘few’ (read ‘a lot of’) items to address, confirm, clarify, etc.

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