What is the Strongest Geometric Shape Used in Construction?

March 4, 2024

For all the unsung heroes in construction, let's give them some respect. It's hard to imagine how crooked AF buildings would be without them using geometry to keep everything straight. From planning and design to the actual building, geometry plays a big part in making structures strong and able to stand up to different forces like earthquakes and heavy weight. So what is the strongest geometric shape used in construction?

Unlike squares and rectangles, which can shift after the application of force (due to their internal corners), triangles are rigid figures. The unique property that makes a triangle so strong is that the sum of its interior angles is always equal to 180 degrees, a value that cannot change once set. Combined with the fact that each side of a triangle supports the other two, this provides exceptional stability and strength to triangles, which are often used in bridges and buildings for their superior load-bearing capabilities.

To understand this in action, have students try to stack books on a rectangular structure versus a triangular structure. They will notice that the rectangular structure will sway and buckle because the sides can shift, but the triangular structure will remain intact because its angles are fixed, which makes it better equipped to distribute the pressure of the books evenly.

To demonstrate this in a classroom, use prepared shapes made from tongue depressors and brads. Then have students apply different amounts of weight to the prepared shapes, calculating how much each one can support before failing. The results will show that triangles are the strongest of the shapes, followed by arches, then squares and rectangles.


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