Physics of Loretto staircase
The Physics of Loretto staircase is how the Loretto spiral staircase is so incredibly sturdy and durable without any supporting column, easily handling far more weight on it than one would expect.
Its spring-like quality suggests that it functions more like a coil than an ordinary staircase. Placing weight on its upper steps has the effect of compressing the coil, which results in added resistance from the coil sufficient to support far more weight than expected. The elasticity and rigidity of this coil structure dictates how much force it exerts in resistance to added weight on the upper steps.
The helix structure of the spiral enables it to function as a coil in apparent defiance of gravity.
Assembled using only pegs, without nails or glue, the fastening of the stairs at the top is probably not for supporting any weight. Instead, this giant wooden spring supports enormous weight with its coil rigidity. While one physics analysis suggests that the maximum deflection in the stairs occurs on its middle step, it appears more likely to occur at its highest step (just prior to the loft).
This helix staircase may provide insights for string theory, and at least one paper published in Phys. Rev. Appl. (2017) suggests that microscopic and nanostructures can be better built by studying this remarkable staircase.[1]
See also
- Physics
- Anita Sumali, Biomedical Engineering Department, "Texas A&M University, The Column-Less Stair in Loretto Chapel in Santa Fe, New Mexico: Strength Analysis" (with photos)
- David Tománek and Arthur G. Every, "Origin of Unusually High Rigidity in Selected Helical Coil Structures," Phys. Rev. Applied 8 - 014002 (July 10, 2017)