The Eiffel Tower is moving. Under the effect of the heatwave and the strong heat in general, this symbol of Paris distorts slightly, by a few centimeters. "Iron expands when it is heated and the whole tower moves", explains historian and architect Bertrand Lemoine at the microphone of Europe 1. This phenomenon affects many metal monuments, but of which the Eiffel Tower is the most famous example .
A movement of about twenty centimeters
“What happens is that there is one side that is exposed to the sun, while the other side is in the shade. The part that is towards the sun expands more, so the tower twists. ", explains Bertrand Lemoine. This movement gives her a certain life: "She will bend slightly, as if she wanted to get away from the sun." Since the sun is rotating, the exposed faces will therefore vary during the day. "This curvature will move and this is what will create this small movement in the sun", specifies the historian.
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In total it is a shift of about twenty centimeters that lives the top of the monument, a tiny movement compared to its 74 meters wide and 324 meters high. According to Bertrand Lemoine, "you can't feel it, it's imperceptible and progressive. It doesn't expand all of a sudden."
This twist is, moreover, temporary, since "the top of the tower, at night, will return to its position", recalls the historian. Thus, if her movements are not spectacular, "this old lady keeps a certain flexibility", smiles Bertrand Lemoine.