Steel, concrete, and wood are three of our most versatile building materials—but there are lots of others, including composite materials and plastics. Architects and engineers use many different materials in their constructions and choose one material instead of another for a variety of reasons. Concrete is the material of choice for large structures such as bridges and tunnels because it is strong, long-lasting, waterproof, fireproof, relatively inexpensive, and easy to mold into curved as well as straight shapes.
Suppose you were designing a skyscraper. How would you go about choosing the materials?
First, you’d need to know how many stories high the building has to be. That is worked out by calculating how expensive the building land is, how much the building will cost to construct (you can guess roughly), and how much profit the owners want to make. Let’s say you think the building will have to be 100 stories high. You can now estimate how much it will weigh and how much weight it will have to support on each floor. So, you can start to design some sort of a structure that will support that much weight for that height into the air. Probably you’ll use steel and concrete for the structural parts of the building (where the weight will be supported), but you won’t want to build a solid concrete block! So you might hide the structural parts in the center of the building and make the outer parts entirely of glass. But glass is heavy, so you’ll need to factor its weight into your structural calculations too. Moreover, you’ll need to figure out how the weight of the glass is going to be supported by the floor or ceiling of the story it attaches to, or by the outer steel skin of the building.
You’ll also have to think about keeping the building’s occupants warm and comfortable. If you’re making the facade from glass, it’s going to absorb huge amounts of solar heat (something known as passive solar). That’s great in winter because it will help to reduce heating costs, but in the summer it could make the building unbearably hot. So maybe you’ll want to use some sort of tinted or reflective glass that cuts down the solar gain a little?
To figure all this out, you’ll need to understand something about the science of heat energy and how it travels around inside buildings.
You can see that every aspect of a building’s design needs meticulous consideration. Making a building is not just a matter of coming up with something that looks good. It’s about creating a structure that can survive all the strains of the modern world. For that, you need to be just as much of a scientist as an engineer!