Marginal Column

Up the Eiffel Tower with more efficient hydraulics


July 2016


During the renewal of the elevator in the West pillar of the Eiffel Tower, the operators relied on Bosch Rexroth's know-how.

Dr. Olivier Ismeurt leans over the yellowed original design drawings. The project leader for the modernization of the elevator hydraulics in the Eiffel Tower admires the detailed drawings of the components. “But there is no diagram of the overall system and due to alterations in the 1980s, the original condition was no longer present.” Together with his team and the operating company Société d'Exploitation de la Tour Eiffel, SETE, he examined and reconstructed the original technical solution from the early days of industrial hydraulics.

Ingenious engineering

With more than 250 million visitors since it was opened in 1889, the Eiffel Tower is the world's most visited building. Already very early on, elevators lifted people safely and comfortably to new heights. Now Bosch Rexroth has modernized the complete hydraulic system of the elevator in the west pillar. The indirect hydraulic drive follows Gustave Eiffel's design idea. “The earlier engineers were awesome and developed a highly reliable solution with the simplest calculation and production methods,” says Mr. Ismeurt. For the renovation project, Rexroth was able to use state-of-the-art simulation software and check the static and dynamic behavior of the entire system comprising the hydraulics, mechanics and controller in advance. The team was thus able to ensure the right sizing and function of all hydraulic components, as well as the overall system.

Up the Eiffel Tower with more efficient hydraulics

25 percent less energy

The modernized hydraulic system adopts the original configuration with two lift cylinders and three pressure storage cylinders. Unlike the original system, valves do not control the up and down runs; instead this is done by variable displacement pumps. Thus, the elevator, which today carries up to 1,000 passengers every hour, consumes about 25 percent less energy than the historical solution. A special challenge for the specialists at Bosch Rexroth: The underground pump room, in which a part of the hydraulic drive system was installed, can only be reached via a relatively small freight elevator. Therefore, they had to partially disassemble the Rexroth components and reassemble them inside the pump room. Access to the machinery room, in which the cylinder had to be installed, was not easy. “I will certainly never forget how the 18-meter-long cylinders were lowered with centimeter-like precision into the machinery room,” recalls OlivierSoret, who was responsible for the commissioning of the Eiffel Tower-hydraulics at Bosch Rexroth in France.