concrete-properties and NZS3101 design

A while ago (like over a year now), I added the New Zealand concrete design code to the excellent concrete-properties repository. I had COVID and got really bored, and actually ended up completing something! I’ve realised I never posted anything about it here at the time. It took about a week of work to get things mostly up and running and a lot longer to finesse and get the code committed to the repository. Basically, the concrete-properties repository allows you…

More wood = more sustainable?!… Screw those trees

Timber, what can I say…. well probably if you could be bothered listening you’d hear a lot of unintelligible colourful mutterings if you get me started and I’m having a bad day on the timber design…… Sometimes I’m a fan of timber as an engineering material, other times not. Some people create beautiful structures from timber, just not me. I can see it is a comparatively ‘cheap’ material compared to steel or concrete, but from a design & detailing perspective…

Plotting dynamic ranges in Excel

One annoying thing about using charts in Excel to represent data is that by default it encourages you to define a finite sheet range to plot data. This can be annoying when you’re dealing with data where the total number of entries is dynamic. For example, say you’re plotting a moment or shear diagram, you need to know the maximum number of data points beforehand to ensure you’re not missing out on any data being plotted at the end of…

Functions for calculating the New Zealand seismic ‘Parts’ coefficient (Part 6)

Following on from the previous posts in this series where we calculated the seismic coefficients from NZS1170.5 and generated ADRS curves. This post covers generating the parts and components coefficient in accordance with Chapter 8 of NZS1170.5. Some time ago I added VBA functions to the GitHub repository to cover this, I just never got round to posting it on the blog. If you don’t know what a ‘part’ is in terms of seismic loading, get out from under your…

Update to ADRS curve generation functions … now works in Excel 2019 plus random side-tracking… (Part 5)

As pointed out here in a recent comment by user Jason on the last post in this series, the VBA code for generating ADRS curves did not work in Excel 2019 as it turns out Excel 2019 does not include all of the worksheet functions that are included in Excel 365. Bad Microsoft! Basically, they don’t want you to buy Excel 2019 I guess, or should I say they’re really providing less incentive to buy Excel 2019. They like you…

How have I not known this ….. until now …

Recently came across this thing in Excel completely by accident, unsure how long it has been a thing? I’ve never ever read anything about it before on the internet or ever seen anyone using it before. Maybe it’s been a thing forever, maybe not. Really have no idea. Anyway, it’s one of those things when I discovered it, I was like, how have I not known this until now? So, what on earth am I rambling about? When in an…

Built-up steel section properties using some good old Python (Part 7)

No python here, sorry to disappoint. I thought I’d post some useful AISC videos which reinforce all the rubbish I’ve been talking about (and lots of stuff I barely touched on) in this series regarding the strengthening of members. Some of the finer points they can explain a whole lot better, and they go into a lot more detail regarding specific aspects of the design of strengthened members themselves and some other things to keep you awake in the middle…

Built-up steel section properties using some good old Python (Part 6)

In this part we visit adding angles nested into the web/flange interface. This is kind of a good means to increase both the bending and axial capacity of a member. Though it results in a bucket load of welding, it’s an effective means of strengthening when you have access and can’t really increase the overall footprint of the member. Basically, when those pesky architects won’t let you attempt to decapitate people by adding something under the member when head heights…

Built-up steel section properties using some good old Python (Part 5)

In this part we consider adding a parallel flanged channel (PFC) or I-Section to the flange of an I-Section. This configuration is used quite often for crane rails (for adding a channel) to deal with lateral thrusts from a runway crane of for simply strengthening a beam for flexure and getting a little more bang for your buck than simply adding a plate to one flange. For the case of adding an I-Section, this comes up quite often in buildings…

Built-up steel section properties using some good old Python (Part 4)

In this part we cover adding a tee to the flange of an I-Section. It’s a good way of increasing the bending resistance of a beam or stiffening it up if you’re improving the deflection performance as there’s a good benefit to be had from increasing the overall depth of the section. You of course have to have the room or clearances to be able to do this. Firstly, let’s mention something else to be aware of when strengthening members,…

Built-up steel section properties using some good old Python (Part 3)

In this part we cover slapping some plates on the sides of an I-Section before unleashing the welder to make some fire. But first I wanted to touch on an important aspect, in the previous post we discussed the strengthening elements being in intimate contact and that fact that this could lead to incorrect results. The other aspect I wanted to discuss regarding the correctness of calculated torsional properties is whether or not you have continuous or intermittent welding. Why…

Built-up steel section properties using some good old Python (Part 2)

In this part we cover welding a flat plate to a flange. Firstly, a couple of housekeeping issues….. Most people (and commercial software) approach the calculation of properties for built-up shapes by slapping a plate hard against the section resulting in intimate contact between the plate and section. Effectively the strengthening element becomes part of the flange of the section. They then read off the properties, job done…. But I propose this is incorrect with respect to the calculation of…

Built-up steel section properties using some good old Python (Part 1)

Over on Eng-Tips forum, the question seems to come up quite regularly regarding the calculation of certain steel member section properties when you’re in the situation of having to strengthen a member with added reinforcement. Usually, the question is related to calculating the torsion or warping constants when some additional strengthening member is welded somewhere on the section, because that’s where simplified rules seem to run out of steam. It’s been a while since I did anything python related on…

What’s the point (load)?

Quite often in structural engineering we make simplifications to make things easier for ourselves. Sometimes they are conservative, sometimes not. Sometimes we are happy living in denial regarding the differences that might exist form doing something in a more ‘correct’ manner, sometimes not. It’s a matter of judgement. One thing we often do is to simplify a series of regularly spaced point loads into an equivalent UDL. Do we ever worry ourselves on how accurate this really is? Today I…

VBA functions for determining (and graphing of) moment, shear, and deflection for a simply supported beams +/- cantilevers (Part 3)

Well after saying here that there was limited practical use for point moments for a simply supported beam, so I wasn’t going to (didn’t see a need to) include them. I’ve eaten those words now and added the ability to consider point moments. Thanks to some work I’ve been doing recently at work on steel design using the alternative design provisions within NZS3404 for combined actions checks, I found a practical use for having applied moments considered in working out…

Using error bars to highlight chart values

This is a handy technique that I was recently reminded of, using error bars to highlight values on XY scatter charts. If you have an Excel chart you might often have the need to highlight a certain value of interest. Usually in these instances I’d plot another data series and add some markers to highlight these points. I’m often guilty of adding some additional horizontal and/or vertical lines as another series to the X and Y axis to enable easier…