Chemistry · Foundation

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Thermal expansionRunning
Heat bridge. Temperature swing at 90 K. Predicted growth 0.027 m, Joint allowance 0.012 m. Currently predicted growth is over by 0.015 m.TUNING0.012 m0.027 mΔ90 K
t = 0.0s

Predicted growth

0.027m

Joint allowance

0.012m

Predicted growth is over by 0.015 m

90 K

Heat bridge. Temperature swing at 90 K. Predicted growth 0.027 m, Joint allowance 0.012 m. Currently predicted growth is over by 0.015 m.

What has to balanceΔL=αL0ΔT\Delta L = \alpha L_0 \Delta T

What is happening

You arrive at a 25 m steel footbridge installed on a hot afternoon.

The joint will be torn apart by the first hot spell. The 25 m steel span allows exactly 12 mm of growth, steel expands 12 millionths of its length per kelvin, and the assumed temperature swing is wrong.