• Dr. P. D. Weidman
  • University of Colorado
  • 108 Surge Building
  • 4:00 p.m.
  • Faculty Host: Dr. Cornel Sultan

Equations modeling the shape of the Eiffel Tower are investigated.  One model, based on equilibrium of moments, gives the wrong tower curvature.  A second model, based on constancy of vertical axial stress, does provide a fair approximation to the tower's skyline profile of twenty-nine contiguous panels.  However, neither model can be traced back to Eiffel's writings.  Reported here is a new model embodying Eiffel's concern for wind loads on the tower, as documented in his communication to the French Civil Engineering Society on March 30, 1885.  The result is a nonlinear, integro-differential equation which may be solved to yield an exponential profile.  An analysis of actual panel coordinates reveals a profile closely approximated by two piecewise continuous exponentials with different growth rates.  This is explained by specific safety factors for wind loading that Eiffel & Company incorporated in the design and construction of the free-standing tower.