So, what exactly is it that an engineer does?

There’s massive confusion out there about the role civil and structural engineers fill in society.

When I let people know that I’m a structural engineer, they know it has something to do with math and science, and it does; they’re right. They’re also pretty sure that it has something to do with buildings, and they’d be right about that, too. But from there, it gets a little nebulous. The distinction between structural engineers and architects is pretty blurry from a layperson’s point of view– people know that they both “design buildings”. So, is structural engineering synonymous with architecture? Are structural engineers qualified to do the same things that architects do, or do they do something different? And then what on earth is this civil engineering/structural engineering distinction all about? Très confuse.

It’s probably most useful to think of buildings as being much like a human being. There are a lot of parallels between the two– the musculo-skeletal system (which is like the structural system in a building) keeps a person standing. The circulatory system (HVAC– heating, ventilation, air conditioning) regulates blood pressure and keeps fluid flowing through the veins. There’s a plumbing (mechanical, electrical, plumbing, or MEP) system, and skin (curtain walls, waterproofing membrane, EIFS) that keeps bad stuff out and good stuff in, and a person has to stand on a stable surface (foundation) to keep from falling over. It’s a really apt analogy.

Keeping that metaphor in mind, the architect has a big job: they figure out exactly what the person looks like. Where the arms go, where the legs go, what the face looks like, eye color, hair color, where the elbows bend, how far the knees are supposed to bend… Things like that. In terms of a building, they determine the layout, the look of the building, how the building is to function, the aesthetics of everything… It’s a huge and complicated job.

The structural engineer gets the plans for the person, and they figure out the mechanics of the musculo-skeletal system. Where do we put the bones, where do we attach the muscles so that the body is able to do all the things that the architect has specified? In the building context, they determine placement and sizing of beams, columns, slabs, foundation specifics, and all the systems that are used to resist the different loads (wind, snow, earthquakes, falling anvils, bookshelves, things like that) which the building needs to be able to absorb and transmit to the ground.

There’s an MEP engineer (mechanical, electrical, plumbing) that determines how the nervous system functions, how the plumbing is all supposed to work, and designs the respiratory system so that everything that needs fresh air gets it. All the wiring and plumbing in a building is dictated by the MEP.

Beyond that, we have to abandon the human being analogy and look at how the building is connected to and interfaces with the rest of the world. Waste and drainage pipes have to be taken from the building and connect to municipal sewer systems. We need to hook up water connections from the municipal water supply to the building. We need to make sure that cars can reach parking lots, that parking lots are sufficient for the needs of the building, and that everything drains properly so you don’t end up with puddles everywhere when it rains. All this is the domain of the civil engineer.

Through intense coordination with one another, everyone on the design team works together to assemble plans for a seamless building design. At the best of times, we create something that functions as it ought, that is a shelter from the elements, that stands strong and tall, and that is comfortable for living, working, and playing. That’s why I love what we do.

Here at Thalia, we’re pleased to provide both structural and civil engineering services… If your needs are design, or analysis, or forensic, we’re here to help you.


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