Those Who Don't Know Their (Structure's) History are Condemned to Repeat It

Over the past month or so I have been helping a new colleague start a secondment role at a large industrial site where I have done a lot of work over the past 10 years. In the short time he has been on site there have been at least 4 incidents where damage has been identified in structures where I (as an outside consultant) know more of the history of the issues than those on site seem to (at least so far as I can tell):

The Day I Almost Became a Statistic

About 18 months ago now I came as close as I ever want to be to being an industrial accident statistic. A fairly simple inspection of a small walkway almost ended up in disaster. This post shares some of my thoughts about it, in the hopes that it can help someone else avoid a similar incident.

What Happened

I was inspecting a conveyor structure with one of our graduate engineers, taking measurements for a repair strategy we were developing. While walking back along the conveyor towards the cribroom (we had finished for the day) we noticed that there was a heavily corroded access platform on one of the conveyor trestles. Both of us were concerned that it might be unsafe, so I decided that we needed to take a closer look at it.

Monorails and Flexural-Torsional Buckling

Shortly after writing my previous post on structural integrity, I came across a great real world illustration of why engineers who specialise in structural integrity are valuable. It was also interesting because it made me realise that something I had thought was impossible actually is both possible and does occur in real structures.

Let’s Talk About Monorails

Monorails are everywhere in industrial structures - a typical processing plant that I often work in would have 40-50 scattered around the site. These are necessary because pumps, motors, pipework, conveyor pulleys etc. are too heavy to move by hand and the congested nature of these structures prevents access by crane. The monorails themselves are usually very simple structures consisting of a standard “I” section, with bolted supports in the top flange to allow a free bottom surface for a standard beam trolley to run.