Physics · Challenge

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Expansion gapRunning
Heat bridge. Temperature rise at 82.8 °C. Expansion produced 0.0497 m, Gap allowed 0.0192 m. Currently expansion produced is over by 0.0305 m.TUNING0.0192 m0.0497 mΔ82.8 °C
t = 0.0s

Expansion produced

0.0497m

Gap allowed

0.0192m

Expansion produced is over by 0.0305 m

82.8 °C

Heat bridge. Temperature rise at 82.8 °C. Expansion produced 0.0497 m, Gap allowed 0.0192 m. Currently expansion produced is over by 0.0305 m.

What has to balanceΔL=αLΔT\Delta L = \alpha L \Delta T

What is happening

You take control of a steel footbridge being set on its bearings in winter.

Nobody recorded the summer rise the bearings were sized for. The 50 m span expands by 0.000012 per degree per metre, and the gap was set at 0.0192 m.