The Igloo and the Natural Bridge as Ultimate Structures

  • Richard L. Handy
Keywords: Long-tailed Jaegers


The Eskimo snow igloo is not a hemisphere as frequently depicted, but a catenoid of revolution with an optimum height-to-diameter ratio. This shape eliminates ring tension and shell moments and therefore prevents failure by caving or bulging. Rainbow Natural Bridge, Utah, is a catenary, probably because of weathering along the trajectory of maximum compressive stress.