Evidence of mankind’s use of arches dates back beyond 2000 B.C. The ancient Romans used arches to construct bridges and aqueducts across their empire. Arches made building the most impressive and beautiful churches and temples across the world possible. Arches, in varying forms, continue their reign as a fundamental building block in the 21st century.
Arches are simple on the surface, but their physics is complex. The curved shape of the arch allows it to resist and transfer a huge amount of compressive force from above to its foundation. This process converts the compressive force into thrust force at the bottom of the arch. The thrust force is managed with reinforcing abutments, buttresses, and other constructs that prevent the thrust forces from crushing the bottom of the arch.
Masonry arches consist of four main parts: the foundation, the pier/impost (sides), the voussoir (the curved part), and the keystone.
Which part of the arch is most important? Put another way, which part of the arch can we do without?
Some would say the arch won’t stand without its keystone at the top. Others might say the sides are most important since they give the arch its height and create the open space that makes arches useful in the first place. Without the voussoir, the arch wouldn’t have its curve. What about all of those thrust forces? With this in mind, clearly the foundation and its abutment structures are the most important part of the arch.
The arch won’t stand unless all of its parts work in unison. Each part of the arch is critical to the success of the other parts. Absence, or weakness, of any part will weaken the arch and could lead to its collapse.
I see the arch as a great metaphor for many of the organizational structures we have today. Families, businesses, charities, governmental entities…to name only a few. All have “arch-like” qualities. All are made up of multiple parts, relying on each other, organized into some type of hierarchy.
Their power comes from creating a strong, protected space where each of us can thrive. Unfortunately, their potential for weakness lies within each of us, whether we’re the foundation, the sides, the voussoir, or the keystone.