At The Henry Ford, Conservation’s job is to maintain artifacts as close to original condition as possible while also ensuring access. The Dymaxion House is a fairly fragile aluminum structure, and a very popular exhibit, which makes preservation a little bit of a challenge.
Last year we did some rather major surgery on the Dymaxion House. We opened up the floor and patched all 96 aluminum floor beams to reinforce them where many had developed cracks.
As I explained in past blog posts, linked below, the damages were found primarily on the heavy-traffic side of the house, where our guests walk through. The repair job in 2012 took two months of hard work.
After all that effort, how do we ensure that this kind of damage won’t progress?
This year we are setting up some cool monitoring devices that will help us understand the house better.
All metal structures move. We want to figure out how our beams are moving, and whether the structure can continue to withstand the forces we apply to it.
Under the guidance of our own engineer, Richard Jeryan, who is retired from Ford Motor Company, and with the generous assistance of Ford Senior Chassis Test Engineer Dave Friske and two skilled technicians, Instrumentation Expert Walter Milewsky and Fastener Lab Technician Richard Talbott, we are installing stress and strain gauges along with crack detection and propagation gauges.
These gauges are the kind of very precise instrument used by engineers to find out how structures perform. They are used to test automobile parts (even ones as small as bolts) during design, and are also used on buildings and bridges.
Strain gauges are used to measure the amount of deformation (strain) when a building is loaded. Put another way, stress is a measurement of the load on a material, strain is a measure of the change in the shape of the object that is undergoing stress. We will be recording a baseline stress on the beams with the house empty of people and collecting our strain data on a busy week in the museum (like the Fouth of July!).
The crack detection gauges will alert us to a crack that is starting, and the propagation gauges will tell us how quickly a new crack is progressing.
These tiny devices are glued onto the beams and wires soldered onto them so that electrical resistance can be monitored with special equipment. Engineers gather the electrical resistance data and use formulas to calculate the degree and character of stress. We are applying the gauges in a number of locations to gather the best overall picture of how the beams move.
We also measured the deflection of the structural wire “cage” using a fancy laser-level and we recorded the data. This will enable us to compare yearly readings during our annual inspection to determine how the cage may be moving.
This is science and technology – working for preservation.
Clara Deck is a Senior Conservator at The Henry Ford.