Engineering in the Eiffel Tower
WHY THE EIFFEL TOWER IS MADE OF IRON
Gustave Eiffel said “First of all, its resistance. From the viewpoint of loads one or the other of these materials can support, we know that for any given surface area, iron is ten times more resistant than wood and 20 times more resistant than stone.” He points out: “It’s above all in the large constructions that the metal’s resistance makes it superior to other materials. The relative lightness of metal constructions also allows for smaller supports and foundations.”
WIND RESISTANCE
The tower moves in the wind. On days with high, gusting winds, the wind can reach speeds in excess of 100 mph at the top of the tower. Visitors can feel the tower swaying gently at the top level. Under such wind conditions, the tower is usually closed to the public, although there is always an engineer present at the summit to monitor telecommunications equipment. The magnitude of the sway in the tower, under worse case condition , is about six inches. There is no danger of the tower being damaged by wind-induced movement since it is designed to withstand movements easily five times beyond those produced by the highest winds ever recorded. Today, the movements are monitored by a laser alignment system.
Gustave Eiffel said “First of all, its resistance. From the viewpoint of loads one or the other of these materials can support, we know that for any given surface area, iron is ten times more resistant than wood and 20 times more resistant than stone.” He points out: “It’s above all in the large constructions that the metal’s resistance makes it superior to other materials. The relative lightness of metal constructions also allows for smaller supports and foundations.”
WIND RESISTANCE
The tower moves in the wind. On days with high, gusting winds, the wind can reach speeds in excess of 100 mph at the top of the tower. Visitors can feel the tower swaying gently at the top level. Under such wind conditions, the tower is usually closed to the public, although there is always an engineer present at the summit to monitor telecommunications equipment. The magnitude of the sway in the tower, under worse case condition , is about six inches. There is no danger of the tower being damaged by wind-induced movement since it is designed to withstand movements easily five times beyond those produced by the highest winds ever recorded. Today, the movements are monitored by a laser alignment system.