# Large structure design

Beyond [design considerations](engineering-design.md), most structures involve balancing loads toward the strongest portions of the frame. This usually represents itself as a large set of triangles, with many of the best designs representing as hexagons.

Typically, large structures have a *tremendous* requirement of load-balancing. If it's a geographically fixed structure, it'll direct the force downward into a concrete foundation. When it's a large structure like a ship or aircraft, the force will be applied to the perimeter of the structure, which will have the strongest metalwork on it.

Concrete itself, as a material, involves a specific process:

1. Gather, break down, and heavily bake limestone to 900 °C for 4-5 hours, then crumble it into powder.
2. Mix the limestone with some other materials to create a cement mix.
3. Thoroughly mix one part cement with 2 parts gravel and 3 parts sand.
4. Add increments of water to reach the right consistency, adding in more mix if too much water.
5. Pour into a form, flatten the top, and let it cure. It takes 1-2 days to avoid footprints, 7 days to reach >70% strength, 28 days to reach full-strength, and will technically keep curing as long as water interacts with it.

Large structures are typically designed for long-term use, so they have *dramatically* more factors to consider regarding weather, erosion, and chemical breakdown. They also suffer *many* more risks from internal failure of various smaller systems (e.g., air conditioner).

## Additional reading

[How Ships Are Built](https://ciechanow.ski/naval-architecture/)