Construction

Construction tools

In 1883 and 1884 the Conservatoire’s construction and architecture collections were developed, when its director, Aimé Laussedat, reorganised this gallery. He took advantage of his contacts with builders and toolmakers to create new exhibits and collect samples of materials. His idea was to show sets of the hand tools used in the various building trades: Ragey donated a collection of tools for carving marble and hard stone, and Gautier Frères offered tools used by wheelwrights, joiners, carpenters and woodcutters.

Models and photographs illustrate construction and engineering techniques. The remarkably precise model of a ‘Paris house’, acquired from Émile Desplanques, is one of the finest pieces in this display.

Pile driver with ratchet winch

Before concrete foundations, most bridges and sea walls were built on wooden piles sunk underwater. Several inventions sought to mechanise this operation, which demanded both power and precision. Machines for sinking piles comprised a block of wood or metal sliding between two vertical guide rails. The block is raised with a winch or rope then allowed to fall on the pile.

This model, formerly in the Institut de France and made with great precision, has a lever that works a ratchet wheel that reduces the physical effort required to raise the block. It was very probably used to test the machine’s kinematics, particularly the working of the winch brake, an innovation that accelerates the raising of the block by limiting the unwinding of the rope each time the block falls.

Bridge foundation on piles

Bridges require solid foundations, and the most common way of achieving this is to isolate a site by shuttering (cofferdam) to temporarily dry it. If the exposed ground is sufficiently firm, concrete foundations can be laid directly on it; otherwise piles are driven into it to create a ‘floor’ on which to build.

This scale model by Charles Nepveu, probably shown at the Universal Exposition in 1855, illustrated a treatise on bridge foundations published by the engineer the same year. The many remarkable achievements of Nepveu’s mechanical construction company include the railway bridge over the Garonne at Bordeaux, whose piles were sunk using compressed air, and the installation of the Machine Hall at the 1855 Exposition. Nepveu also worked in an advisory capacity on the digging of the Suez Canal.

His death at the age of forty ended a brilliant career largely eclipsed by the success of Gustave Eiffel, who began his career in 1856 as Nepveu’s personal secretary.

Machine for raising and replacing capitals

Between 1827 and 1832 major alterations were made to the Palais Bourbon to transform it into the Chamber of Deputies. Dismantling its Corinthian capitals and other decorative elements proved particularly difficult, so the architect and engineer Charles Eck devised a machine to facilitate their removal.

When his invention was shown as a scale model at the Exhibition of Products of French Industry in 1834, it was awarded a bronze medal and acquired by the Conservatoire. The machine has an armature designed to clasp the mass of stone without touching its sculpted sides. Metal struts are slid beneath the block to be dismantled and four pressure screws are tightened from above to maintain it in place so that the capital can be removed by normal methods such as cranes or derricks.

The lifting method in use here, a breast derrick (an A-framed mast supported by guy ropes) was widely used in the 19th century but has long since been superseded.

Lifting apparatus

In 1856 the port of La Joliette in Marseille was transformed by a huge property development masterminded by the financier Jules Mirès. The engineer and builder Paul Borde was contracted to undertake this project on a very short schedule. Only mechanisation could enable the rapid and precise positioning of materials and save on scaffolding.

To achieve this, Borde invented a steam-powered crane on rails running parallel to the facade of the building under construction. Materials could be deposited anywhere on the construction by varying the angle of the crane’s pivoting boom. Only two men were required to operate the machine.

The success of this project won Borde other major contracts in Marseille and then Paris. His lifting apparatus was patented and gradually improved. This scale model, bought by the Conservatoire after the Universal Exposition in 1867, is probably the final version of this machine.

Excavator

The civil engineering contractor Alphonse Couvreux was one of the first in Europe to transform the bucket dredger, initially used for waterway maintenance, into a dry excavator.

In 1859 he registered a patent for a ‘dredger with inclined slings’ for the extraction and loading of ballast in the construction of the Ardennes Railway (1860–63). On the strength of this project, in 1863 Couvreux’s company was awarded a contract to dig a section of the Suez Canal. His presentation of these gargantuan projects at the Universal Exposition in 1867 crowned their success.

For the 1878 Exposition, Couvreux had a scale model made of his latest excavator, used for the modification of the Ghent-Terneuzen Canal in Belgium. The locomotive drives a bucket dredger working perpendicularly to the rails, capable of excavating to a depth of 5 metres. This model was donated to the Conservatoire after the exhibition.

Building site, rue de Rivoli

An impressive apartment building worksite opened at the corner of rue de Rivoli and rue des Feuillants (now rue Rouget-de-l’Isle), the location of the former Ministry of Finance burnt down in the 1871 Paris Commune. Claude Salleron was the architect and Émile Desplanques the builder.

Rigorous organisation of the workers' activity allowed the project to advance at a brisk pace. The use of steam power (produced by a locomobile), a railway and two cranes* ushered in modern building methods. The dressed stones for the façades were numbered, allowing them to be quickly assembled. They masked brick and iron, the most widely used materials.

In 1880 Parliament voted a special credit allowing the museum to purchase this model, an accurate depiction of the building site.

Liberty Enlightening the World

A project to create a monument commemorating the United States’ independence gained momentum in the early 1870s with the support of the Franco-American Union. The sculptor Auguste Bartholdi imagined an allegory of Liberty holding up a torch to enlighten the world.

The technical challenge of constructing this gigantic figure was taken up by Gustave Eiffel, who designed an iron tower on which to fix the hammered copper plaques which when assembled would form the statue. To test the work’s structural viability, in 1884 Bartholdi constructed the towering figure in the courtyard of the workshops of Gaget, Gauthier & Cie in Paris. Seizing this opportunity to finance his project, the sculptor opened the statue’s construction to the public, and paying visitors flocked to admire the metal colossus rising above the city’s rooftops. The statue was then dismantled, packed in cases and shipped to New York, where it was finally inaugurated in 1886.

This painted plaster 1:16 scale model, standing triumphantly on the ornately decorated plinth housing a small diorama, was donated to the Conservatoire by Bartholdi’s widow in 1907.

S550C concrete mixer

This concrete mixer is the symbol of a French company that in only thirty years became one of Europe’s leading construction equipment makers. Paulin Richier founded the company in a 30-square-meter workshop in the late 1920s.

For this concrete mixer alone he registered some fifteen patents between 1929 and 1939. They were for improvements in dosing liquids, optimising mixing, and the automation of loading and unloading. In the late 1950s, the company organised exhibitions, producing catalogues and scale models celebrating this prosperous period during which its three French production sites exported a complete range of construction machines all over the world.

Its purchase by Ford in 1972 marked the beginning of its decline, and it went into voluntary liquidation in 1982.

Roof and attic structure of a building in Saint-Germain-des-Près

This model is a painstakingly precise reproduction of the monumental attic of a building demolished during the winter of 1874 to create the Boulevard Saint-Germain. Its structure, ‘à la Philibert de l’Orme’, was named after the architect who was the first to publish this construction principle in the late 16th century.

This original roof structure was probably constructed around 1800, after the rediscovery of this type of weight-bearing structure of small pieces of timber, reinvented and popularised by the cupola of the Halles aux Blés designed by Legrand and Molinos in 1783. This roof is in fact composed of two structures: the ‘de l’Orme’ roof and the original polygonal attic floor structure. This model and the four accompanying plans are the work of the Parisian joiner and schoolteacher Beloni Minard, who also made the models of the domes of Les Invalides (inv. 10969) and the Institut de France (inv. 11757) that were part of the same educational and artistic project shown at the Universal Exposition in 1889.

Scaffolding erected to build the iron dome of the Halle aux blés

The Halle aux blés ("corn market"), now the Bourse du commerce ("commodities exchange"), is emblematic of the covered markets being rebuilt in Paris in the mid-18th century.

In 1783 the architects Legrand and Molinos crowned the building with a spectacular wooden dome 22 metres in diameter that brought Philibert de l’Orme's process back into use. The dome burnt down in 1803 and the architect Bélanger replaced it with a cast-iron one. Assembling the heavy structure required the erection of a temporary frame, built by the carpenter Quantinet, that was nearly as stunning as the dome itself.

We do not know who made this model, which accurately shows what was probably the scaffolding's final version. The dome, still in place, owes much of its design to the engineer Brunet and influenced the architects of the London Coal Exchange (1849) and the Leeds Corn Exchange (1863).

Construction of an annexe gallery for the 1878 Universal Exposition

Henri de Dion devised an economical metallic structure composed of lattice half-arches anchored in the ground.

Although he arrived late in the construction of the 1878 Exposition, for the Machines Hall he succeeded in replacing the Polonceau trusses initially planned with his system. The calculations he had just published showed that further economising on materials was possible. When, a few months before the opening, it was discovered that the Machines Hall was not big enough to contain all the planned exhibits, the construction of an annexe gave the engineer an opportunity to put his new theory into practice.

Sadly, he died before the exhibition’s opening and never saw his project completed. The builders of this construction, the Moisant company, had this scale model made. It was shown in the civil engineering section of the Exposition then donated to the Conservatoire.

Construction of the interior galleries of the Palais du Champ de Mars

From the first in 1851, universal expositions were opportunities to experiment with new construction techniques, and the 1878 Exposition was exemplary in this respect. The Palais du Champ de Mars, specially built for the event, covered a 25-hectare quadrilateral. The glass roofs of the interior galleries were supported by metal Polonceau trusses with a 25-metre span. Four companies were selected to each construct three sections of fifty-eight trusses. These lucrative contracts were also exceptional opportunities for these builders to demonstrate their skills. Émile Baudet decided to assemble the elements on the ground then raise them using a steam-powered machine mounted on travelling scaffolding. A scale model of this apparatus was made for the Exposition and donated to the Conservatoire after the event.

The Britannia Bridge

The success of the first world’s fair, the Great Exhibition in London in 1851, prompted France to organise its own in 1855. Despite the protectionist attitude of the French government, the United Kingdom took part on a massive scale and again demonstrated its technological lead.

Two of the railway engineering models shown by the British contingent were particularly admired: the Britannia and Chepstow bridges. Both made novel and daring use of gigantic tubes composed of riveted sheet metal panels, whose lightness and solidity had been demonstrated by William Fairbairn in the 1830s. For the Britannia Bridge, opened in 1850, the engineer Robert Stephenson, assisted by Fairbairn, passed each railway track through a square, self-supporting steel tube 4 × 8 metres in section. The bridge consists of two tubes 461 metres long, resting on three masonry piers forming arches with a span of 80 to 140 metres. For the Chepstow Bridge, built between 1850 and 1852, Isambard Kingdom Brunel used two steel tubes 2.74 metres in diameter resting on two vertical structures 90 metres apart. Each track is suspended from one of the tubes by tubes braced with diagonal struts. The ensemble forms a large lattice span, extended by two other 30-metre spans.

Charles Nepveu’s donation of these two models to the Conservatoire in 1857 bears testimony to French and English engineers’ mutual interest in each other’s work. Nepveu was known in England for his work on bridge foundations.

The Chepstow Bridge

The success of the first world’s fair, the Great Exhibition in London in 1851, prompted France to organise its own in 1855. Despite the protectionist attitude of the French government, the United Kingdom took part on a massive scale and again demonstrated its technological lead. Two of the railway engineering models shown by the British contingent were particularly admired: the Britannia and Chepstow bridges. Both made novel and daring use of gigantic tubes composed of riveted sheet metal panels, whose lightness and solidity had been demonstrated by William Fairbairn in the 1830s. For the Britannia Bridge, opened in 1850, the engineer Robert Stephenson, assisted by Fairbairn, passed each railway track through a square, self-supporting steel tube 4 × 8 metres in section. The bridge consists of two tubes 461 metres long, resting on three masonry piers forming arches with a span of 80 to 140 metres. For the Chepstow Bridge, built between 1850 and 1852, Isambard Kingdom Brunel used two steel tubes 2.74 metres in diameter resting on two vertical structures 90 metres apart. Each track is suspended from one of the tubes by tubes braced with diagonal struts. The ensemble forms a large lattice span, extended by two other 30-metre spans. Charles Nepveu’s donation of these two models to the Conservatoire in 1857 bears testimony to French and English engineers’ mutual interest in each other’s work. Nepveu was known in England for his work on bridge foundations.

The Jarnac Bridge

In the late 18th century, to reduce the long and costly construction time of masonry bridges and do away with their arches, limited to 30 metres, engineers began designing metallic suspension bridges. Influenced by the bridges built first in the United States then in England, the Seguin brothers developed their own original technical solution.

Instead of suspending the deck on chains, they used specially made iron cables and built their first bridge in 1825, over the Rhône at Tournon. A year later, Jacques Pierre Quénot, a classmate of the Seguin brothers, began building a suspension bridge over the Charente. When construction was halted by severe winter weather, the project’s foreman, Mr François, continued the construction … in miniature!

This model, shown at the Exhibition of Products of French Industry in 1827, publicised the technique with which Quénot went on to construct some twenty bridges. Donated to the Conservatoire by the engineer’s heirs in 1863, it is the only three-dimensional representation of the bridge, which was destroyed in 1875.

The Malleco Viaduct

When it was inaugurated on 26 October 1890, this viaduct crossing Chile’s Malleco River at a height of 102 metres was the highest in the world. Incorrectly attributed to Gustave Eiffel, it was in fact designed by Aurelio Lastarria, a Chilean engineer trained in Europe. Following an international competition in which the Eiffel company also took part, the contract for the viaduct’s metallic structure was won by the Schneider company at Le Creusot, which showed this model at the World’s Columbian Exposition in Chicago in 1893, then at the Universal Exposition in Paris in 1900.

This 347-metre-long lattice bridge has five spans with a total weight of 1,410 tonnes, resting on four metallic piers, the tallest of which is 76 metres high. Still in use, it was reinforced in 1927 to withstand the increasing weight of rail traffic. It has been on the list of nominations for UNESCO World Heritage status since 1998.

Staircase from the Blandeck [Blendecques] tin mill near Saint-Omer

This spiral staircase has eight balanced flights that give the load-bearing stringer a remarkable double-helix structure. It is a technical feat by a craftsman with a sound grounding in geometry, which probably explains why it entered the Conservatory's collections in the early 19th century.

The work may have been the "masterpiece" of a skilful journeyman carpenter, but all the evidence suggests it was a model of the staircase in the main building at the Blendecques mill, later called the "Château Montreyan". Resembling the tidy architecture of a square pavilion, like the double helix staircase in the casting room of Buffon's forges it probably helped lend metal production a noble air.

The Blendecques "tin mill" built in 1777 was probably designed in imitation of an English factory. In addition to showing off a carpenter's skills, this staircase is a splendid example of late 19th-century industrial architecture.

Double spiral staircase with elliptical central 'lantern'

Building a staircase requires mastery of the art of joinery. The thin, regularly spaced vertical grooves on the central core (the ‘lantern’), suggest that this model was used for teaching purposes. In 1770, advice in Description of the Arts and Crafts – one of whose contributors was the master joiner André Jacob Roubo – for staircases with an elliptical plan was to divide the tread supports, core and stringer equally to obtain regular steps.

The fact that this is a double staircase adds nothing technically but enhances the aesthetic balance of this model, which could well have been the ‘masterpiece’ of a journeyman carpenter. It joined the collection before 1814, and may have been seized during the French Revolution.

Scale and accessories

Following Louis Vicat’s research into concrete in the early 19th century, around 1850 the first tests to measure the tensile strength of lime and cement mortars were devised.

H. Fruhling and W. Michaëlis, who sought to standardise these measurements, showed a small-scale traction machine at the Universal Exposition in 1878. The Commission on Methods of Testing Construction Materials adopted it in 1895, and the Conservatoire acquired one from the precision instrument makers Ponthus & Therrode in 1907. To determine a mortar’s tensile strength, a sample of the mortar to be tested is first mixed in a standardised figure-8-shaped mould. When the mortar has hardened, the sample is placed between two claws then progressively stretched by a lever lowered by a container filled with lead pellets. The weight required to rupture the sample gives a precise measurement of the sample’s tensile breaking strength.

Théâtre des Champs-Élysées

The Théâtre des Champs-Élysées, which opened in 1913, is a 3,000-square-metre, five-part complex including a 1,200-seat main performance hall. The Perret brothers had already designed several groundbreaking projects, but this one thrust them into the vanguard of modern architecture. Roger Bouvard's original plans, revised by Henry Van de Velde, called for a stone building.

The Perret brothers innovated by opting for an exposed concrete skeleton, which immediately sparked controversy: it shattered the architectural conventions of what a "French-style" theatre should be. Fortunately, the main auditorium soon earned a reputation for excellent acoustics, which Auguste Perret had theorised, and which the press covered.

The Perret brothers' archives, which were given to the Conservatory in 1956, contain the famous axonometric view of the theatre's skeleton drawn by Auguste Perret in 1913, upon which this model is based.

Aeroplastic model of pier P2 of the Milau Viaduct

Designed by the engineer Michel Virlogeux and the architect Lord Norman Foster, the Millau Viaduct is a spectacular feat of civil engineering. A crucial link in the north-south crossing of the Massif Central, it was the last section of the Clermont-Ferrand-Béziers motorway to be completed. Crossing the Tarn Valley between the Larzac plateau and the Causse Rouge, it required major preparatory work and a host of preliminary studies.

This experimental model was made by the French building industry’s scientific and technical centre to carry out aerodynamic tests. The vibrations produced by the emitter at the base of P2, the tallest of the viaduct’s piers (343 metres high), enabled the laboratory to analyse the viaduct’s behaviour in gale force winds.