Ferris Wheel of Paris - Expo Paris 1900

A famous copy of the 300-metre tower erected on the Champ-de-Mars, the Wheel without equal is commonly referred to as the Great Wheel of Paris. It stands on Avenue de Suffren opposite the famous Galerie des Machines at the 1889 Exhibition.

The first idea for this type of construction belonged to an officer of the American Navy! Mr. Graydon, who recorded the principle and method of execution in a patent dated September 1893.

The present project was developed by an English company. The assembly operations were carried out under the direction of an English engineer, Mr. Slitckins; to Mr. Walter B. Basset was entrusted with the general building work, the installation of the equipment necessary for the rotation of the wheel and its lighting. This engineer had gained experience in this type of industrial architecture in three other projects that preceded this one, in Blackpool (England), London and Vienna. The first wheel was built for the Chicago Exhibition. All these specimens do not reach the dimensions that particularly distinguish the one in Paris.

The metal used in its composition is steel.

Since we have to mention the collaborations, it is worth mentioning that all this metal mass comes from a French factory belonging to the Société des foires et aciéries de Haumont (Nord), and comprises no less than 800 tons of metal.

Essentially, this wheel is designed to rotate around a horizontal axis located 67 metres above ground level, moving in two support bearings which rest, after interposing a thick oak sole, on two pylons, the construction of which we will indicate later; on its periphery are a series of wagons, driven in the rotational movement of the apparatus.

The diameter of the wheel is exactly 93 metres; at the lowest level at which they can descend, the wagons are still 3 metres above the ground; therefore, at their highest point, they reach a height of 96 metres. Between the two outer rims are suspended by a system similar to a pendulum suspension, a number of carriages capable of accommodating the most diverse destinations; lounges, parlours, dining rooms, smoking rooms, reading rooms, concert halls, reading rooms, rest rooms, rooms for aerial observations, etc., etc., etc.

Some of these can be divided and arranged into first and second class compartments, built on two floors, one of which would be used for kitchens, pantries and accessories serving the upper floor.

With a little imagination, one would manage to endow these carriages with the most refined comfort to make their stay pleasant; the seats could be assembled to the tables in such a way as to orientate themselves optionally at the will of the occupant to change his point of view, without appreciable effort on his part. In a word, in these compartments would be brought together all that the taste for well-being and the habits of interior luxury could evoke in the mind.

The total weight of the wheel, including the empty wagons, excluding the weight of the axle and the pylons, is 6,350,000 kilos.

The axle weighs 30,000 kilos, the two pylons 397,000 kilos, so the total weight of the whole architectural monument is 1,083,000 kilos. Each carriage is capable of holding 30 people, with 40 people on the wheel; assuming an average weight of 70 kilos per person, the total load on the foundations is 1167 tonnes.

The foundations are made of Portland cement concrete. Two excavations were made in the ground, in a square of 5.5 metres and to a depth of 12 metres, into which sand, stones and pure cement were poured, without the addition of hydraulic or other lime. Each of the monoliths thus formed weighs 230 tonnes.

The two steel pylons that support the axis are placed on these foundations. Each of them is made up of four lattice columns, connected by heavy steel struts, consolidated by diagonal ties. They were assembled in individual pieces, buttoned and riveted.

The shaft, made of top quality Martin steel manufactured in England, is a heavy hollow piece of about 15 metres in length and with an external diameter of about 0.90 metres. Its transportation on foot required a special carriage and a special hitch. It took 32 enormous percherons to tow this colossal metal ingot. Its journey through Paris was marked by a few episodic incidents. Under the pressure exerted by the fardier, the roadway gave way opposite the Palais Bourbon and it took no less than six hours of attempts and efforts to return it to traffic.

The shaft turns in steel bearings coated with a metal of a particular composition, a mixture of lead, tin and various other substances. This alloy is intended to avoid the friction of steel on steel, which has a very high coefficient.

On each side of the axle, in line with the pillars, 160 flexible steel wire cables, 5 centimetres in diameter, radiate out from the wheel rim. These spokes are fitted with tensioners that stiffen them once they are in place.

The rotation of the wheel is obtained by a double cable that wraps around it and is wound on winches driven by a steam engine with a power of 120 hp, the safety of operation is ensured by several instantaneous brakes that immediately stop the movement. The steam engine will also drive a dynamo, the current of which will supply arc and incandescent lamps, whose glow in space will give the burnt-out wheel the appearance of a luminous meteor.

Electrical communications from the ground will be carried out by cables along one of the pylons, leading to the axle; then from the axle, the current is transmitted to the periphery by a cable, circular plates and contact brushes to the various electrical distribution stations to the cars. The electrical lighting processes of this entire immense structure provide the means to obtain all the desirable plays of light, realising the whole range of an intense and harmonious polychromic palette.

A complete evolution of the wheel takes twenty minutes, including stops. Access to the cars is achieved by a system of stairs and landings arranged in such a way that 8 cars can be loaded and unloaded simultaneously, without obstruction and in less than a minute. Each wagon is 13 metres long.

It is worth mentioning the procedure used for the assembly of this huge machine. For this purpose, two grandiose scaffoldings made of Lorraine fir were erected, at the top of each of which a steam crane weighing approximately 9,000 kilos and capable of lifting 3,000 kilos at a time was established. The arm of these cranes was 30 metres high and could move the load within a radius of 27 metres. The two cranes and their respective scaffolding are set up on either side of the wheel, symmetrically in relation to a diagonal passing through the central point, so that the entire site is within the range of the two washing machines. The weight lifted per week by each crane was 200,000 kilos. As the combined force of the two cranes is only 6000 kilos, the assembly of the axle required the use of several winches fixed firmly to the ground, the effects of which were amplified by the addition of differential hoists. The traction cables were wound on pulleys installed on the top of the pylons. As it was lifted, the heavy piece slid along the uprights.

In plan, each scaffold forms an isosceles right-angled triangle whose equal sides are 17.5 metres long. Each of the vertices of the geometrical figure is occupied by a square pylon of 3.5 metres side length, similar to those erected in front of the facades of houses under construction in Paris. The four pylons are solidly bracing and braced against the wind, as well as the group of three pylons, by cross-sectional planks of 0.30 x 0.15 m. Contrary to common practice, the pylons are not embedded in the foundations: they simply rest at ground level on a concrete mass of pebbles and cement.

The Faley company, from Paris, was commissioned to supply and build the scaffolding. They realised that the three pylons of the same scaffold did not work under the same conditions: the pylon at the top of the right angle carries the weight of the crane and its driving machine; it is subject to compression. The other two towers at the ends of the hypotenuse, because of their connection to the supporting tower and also to the overhead part of the crane, are subjected to overturning and lifting forces. These simultaneous but different forces are counterbalanced as follows: each tower is supported by galvanised steel wire ropes, which are attached to strong oak piles driven obliquely into the ground up to a depth of 8 metres in a sturdy concrete foundation, and which are connected to the tower at the top and at two thirds of its height.

In order to prevent the lifting of part of the scaffolding, a plank box was built at the base and inside the pylons, the bottom of which rests on a series of planks placed on a 0.60 m thick concrete bed containing 25 cubic metres of stones weighing a total of 40 tonnes. A steel wire rope is attached to this weighted box, which runs vertically up the inside of the tower and is fixed, after two changes of direction on guide pulleys, to the end of the crane's boom.

A quick look at the construction of the wheel, its construction and the composition of the assembly scaffolding will give a clear idea of the elegance of the solutions to the various problems that the technique had to solve. The work finally standing does credit to the imagination and intelligence of the engineers who contributed to its construction. It is quite certain that the majestic operation of such an apparatus is destined to be a resounding success.

The proximity of the Champ-de-Mars promises a large number of visitors during the solemnities of the Exhibition.

©Exposition Universelle de Paris - 1900