The Kalani High School Engineering Class was given an assignment to publicly display knowledge of science, technology, engineering and math. To complete this project, the group of twenty-six students constructed a Geiger Cable Dome, a.k.a. the Tension Dome, in the campus. Using knowledge gained from a The Great Courses lecture about structure (conducted by Stephen Ressler, M.D), the students were able to finish the 20' diameter dome in twenty-four hours of brainstorming, designing and construction. The class was challenged to use wood and sisal rope instead of concrete and steel cabling in real world examples. The design would have to be easily deconstructed, too, so screws or nails would have to be used instead of wood adhesive.
A tension dome is a structural system that uses the tensile strength of materials rather than the compression qualities of usual domes. The Tension-Dome is consisted of five main components: compression ring, centerpiece, cables, stents, and hoop cables.
Compression Ring (a.k.a. outer ring)
-resists the pulling force of the spanning cables
-usually held up by a base
-a piece that acts in tension that resists the pulling force of the spanning cables
Spanning Cables (8)
-connects the center piece to the compression ring
-multiple cables distribute the weight of the dome to the outer ring
-segments attached to the spanning cable
-act as compression members
Hoop Cables or Cable Rings (2)
-act as tension members which pull in the bottom of the stents towards the center
A great real world example of a Geiger Cable/Tension Dome is the Seoul Olympic Gymnastics Dome in Korea (seen in picture above). This dome is able to cover 13,000 spectators in the 1988 Seoul Summer Olympics. Besides the difference in size and the covered roof of the stadium, the principles of this 390 foot diameter dome are exactly the same as our own 20 foot diameter.