Triangles and Arches in Building Design
Gabriel Caluzzi (student), Year 11
Mr. Kneale (teacher), rkneale@unihigh.vic.edu.au
University High School, 77 Story St
Parkville, VIC 3052
(03) 9347 2022
Fax (03) 9347 2658
Description of Physics
This picture shows the use of triangles in a building structure. Triangular shape is almost always used in
architecture and building design due to its simplicity, efficiency, and structural value. It is a rigid shape that
cannot be changed when pressure is applied, and commonly used to reinforce more yielding shapes such as
squares and rectangles. In some situations, a triangular frame can have as much structural strength as a filled
formation of the same material. This is commonly seen in the triangular lining of crane arms and building
reinforcement, and is used due to the fact that it is much more economical and lightweight.
Another key element used in these buildings is arches. Arches are also very strong shapes and are very stable
when built with a material good under compression. A force applied to the top of an arch will be carried
vertically and horizontally in along the length of the arch's sides all the way to its base, applying a compressive
force throughout. Still, very heavy loads can cause an arch to deform, or bend. To overcome this weakness in
the picture above, engineers have created an arch covering all 360 degrees. These arches have becomes strong,
three-dimensional, symmetrical shapes -- domes. Domes are exceptionally stable structures owing to the fact
that they spread their weight out over a full circle.