It's been tough, but I've kept up with my end of the 30 day challenge to post at least once a day about a topic I am an expert in, which is structural engineering. And in case anyone is wondering, I write these bits where I have time which is usually when I'm eating lunch (all 15 minutes!) on my commute to and from work and between site visits. In some cases, I'll write when I'm settled in at home too. This just goes to show that it's every bit as much handwork as you would think it takes. Between a 10+ hour work day, exercising, thinking of what to write for Steemit, making videos and more, I have very little time for myself, but sometimes you have to hustle to get where you want or to learn something new., and there's much more enjoyment coming from feeling accomplished than there is feeling relaxed all the time! Back on to the blog!

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In my last post, we started talking about how a typical large scale project works and we left off with the schematic design phase. I want to dig deeper on the importance of this phase and the need to have a detective hat on at all times.

ENGINEERING DETECTIVE, VISUAL SURVEY

Depending on the situation, an engineer may not have access to the structural drawings for the building they're working on. Sometimes this is simply because they've been lost to time. In fact, there are many commercial buildings in Manhattan that are over 20 stories without any drawings!

This presents a problem for designers because the only other way to figure out how the building was constructed, is to survey it with our own eyes. We'll walk the building and look for areas where the buildings frames are exposed or minimally concealed by the architectural finishes.

But knowing how the frame is setup is not enough. In most cases, we'll request probes, which are essentially micro demolitions on selected areas to reach key elements of the buildings frame. How do we know where these areas are? By experience of course! Most of our probes are intended to reveal connections of the frame members and sometimes to reveal something hidden that we know nothing about.

Most commonly there are 3 different types of frame construction that we see in the world,

• steel
• masonry or concrete
• wood

No matter which construction type exists, we're still missing one key bit of information.

MORE DETECTIVE WORK: MATERIAL PROPERTIES

This may seem silly to non engineers, but we need to know the strength of the framing material. Not all steel, wood or concrete is created equal.

In fact, most steel framed buildings built in the early 1900s were constructed of beams that were not of any standard size or strength. Steel manufacturing plants across the US created their own variations of steel beams to fit their machinery and strength grades varied based on what was locally available. So we often need laboratory testing to determine the steel strength. The tricky part is how we gain access to the samples to test, which is what the next blog will be about! So stay tuned for the next article!

FIELD DATA

All of the items I mentioned above require extensive field work. Your eyes need to be peeled wide open to make sure you can see evidence of modifications, or really anything that can help you understand what the original intent of the design engineer was.

The difficult thing is that this is not something that can taught in school. You need a mixture of understanding structural engineering, load paths, construction, and have a the spacial ability to connect the information you see and read all together.

That's it for today, in my next post, I'll go deeper into the material testing and how we decided where to take the samples!

IN THIS PHOTO, I'M INVESTIGATING THE FRAME LAYOUT ABOVE AN HISTORIC STRUCTURE. AT SOME POINT IN TIME THIS AREA WAS CLOSED OFF AND NO ONE HAS ACCESSED THIS LOCATION IN OVER 50 YEARS. IT WAS ABOUT 95 DEGREES, DUSTY, AND YOU HAD TO CRAWL AROUND EVERYTHING

AN OLD LABOR DAY PARADE NOTICE FROM 1987 THAT I FOUND IN THE SUB BASEMENT OF THIS PROJECT