Uniqueness of Triangle shape is not just in 2D planes.It is a shape which provides immense strength,stability and also helps in reducing cost in 3D structures while building big structures.Triangle structures helps builders to reduce cost and provide strength to the whole structure.Let us look at the 2 factors,cost and strength.
1. Cost – Use less material while still ensuring that the structure is strong and stable. since the triangle obviously has only 3 sides, it requires little material to make a support, thus minimizing the costs.
2. Strength/Stability – Triangle structure not only support its own weight, but also withstand as much external force as it can. Because the triangle does not easily deform and is able to balance the stretching and compressive forces inside the structure.
Overall, a triangle is the simplest geometric figure that will not change shape when the lengths of the sides are fixed. In comparison,both the angles and the lengths of a four-sided figure must be fixed for it to retain its shape.
There are good examples in which the triangular structure or the 3 way structure is used to build big buildings because of these 2 factors.One of such example is Burj Khalifa in Dubai.In addition to its aesthetic and functional advantages,the spiraling “Y” shaped plan was utilized to shape the structural core of Burj Khalifa. This design helps to reduce the wind forces on the tower, as well as to keep the structure simple and foster constructability.To support the unprecedented height of the building, the engineers developed a new structural system called the buttressed core, which consists of a hexagonal core reinforced by three buttresses that form the ‘Y' shape. This structural system enables the building to support itself laterally and keeps it from twisting. The Y-shaped floor plan maximizes views of the Arabian Gulf.
Another example which shows high stability of triangle is the swing. The structure on which the swing is built is usually triangle in shape.Because it provides stability and can uphold the shake and movement of the swing.
Burj Khalifa floor plan