AA - Architects as Engineers in 18thC France

Architectural Association School of Architecture is collaborating with JSTOR to digitize, preserve and extend access to AAFiles.

http://www.jstor.org

ARCHITECTS AS ENGINEERS: THE IRON REINFORCEMENT OF ENTABLATURES INEIGHTEENTH-CENTURY FRANCE Author(s): Robin Middleton Source: AA Files, No. 9 (Summer 1985), pp. 54-64Published by: Architectural Association School of ArchitectureStable URL: http://www.jstor.org/stable/29543451Accessed: 19-08-2014 20:30 UTC

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of contentin a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship.For more information about JSTOR, please contact [email protected].

This content downloaded from 130.63.180.147 on Tue, 19 Aug 2014 20:30:30 UTCAll use subject to JSTOR Terms and Conditions

http://www.jstor.org

http://www.jstor.org/action/showPublisher?publisherCode=aasa

http://www.jstor.org/stable/29543451

http://www.jstor.org/page/info/about/policies/terms.jsp


ARCHITECTS AS ENGINEERS

THE IRON REINFORCEMENT OF ENTABLATURES

IN EIGHTEENTH-CENTURY FRANCE Robin Middleton

rom the late seventeenth century onwards the leading theorists of architecture in France assumed that the refinement of structural

JL form and its proper expression in building was an essential feature in the reinvigoration of the classical tradition on which they had embarked. Their theoretical premise, however, was based on the study of national, Gothic building rather than the architecture of classical

antiquity ? one thinks in particular of theorists such as A. F. Frezier,

J. G. Soufflot and his advisers J. R. Perronet and E. Gauthey, and

J. F. Blondel and P. Patte. All studied the Gothic structural system in the belief that it might be adapted to classical forms. There was no question of Gothic revivalism. They not only demanded a strict adherence to the classical repertoire, they required that it should be more limited in scope than before. In particular they sought to evolve an architecture that relied on the use of the free-standing column and its related lintel ? the column regarded no longer as a decorative feature but as the principal formal and structural element in architecture. There were differences in their opinions, but they all regarded this arrangement as closer in spirit to that of classical antiquity

? and also, paradoxically, to that of their Gothic past

? than the heavily modelled architecture of the late seven? teenth century. The buildings upon which they focused their attention

involved, without fail, columnar episodes, sometimes supporting arches rather than lintels. The history of eighteenth-century architecture in France can be ?

indeed has been ? written with reference to a series of such buildings alone, starting with Claude Perrault's colonnade on the east front of the

Louvre, begun in 1667; passing to Jules Hardouin Mansart and Robert de Cotte's chapel at Versailles, begun in 1698, finished in 1710; and so to

J. N. Servandoni's west front at Saint Sulpice, designed first in 1732,

completed in 1777, and Soufflot's Sainte Genevieve, approved in 1756, with later reference, perhaps, to A. J. Gabriel's buildings on the Place Louis XV, begun in 1758, and to Contant d'lvry's Madeleine of 1763 and his church of Saint Vaast at Arras of 1774. These particular buildings all have columns and lintels; in addition they have in common the use of iron reinforcement in their entablatures. Such use is unprecedented. Metals had, of course, been used structurally in the buildings of

classical antiquity, and even in Gothic construction iron bars were sometimes introduced ? and this was well known; Soufflot, for

instance, discussed the iron reinforcement in the vaults of Saint Etienne du Mont at the Academy in March 1773 (P. V., VLTI, pp. 146-8)

? but the extensive use of iron reinforcement in the columns and lintels of the Louvre colonnade seemed to eighteenth-century theorists to mark a new era in structural enterprise. The Louvre colonnade was upheld

throughout the century as not only stylistically advanced but also, it must be emphasized, structurally. The arrangement of iron bars linking the columns and lintels of the Louvre facade to the stabilizing wall behind was first illustrated ? albeit partially

? in 1755, in Pierre Patte's Etudes d*architecture. Though Patte included the pediment, he did not indicate any iron reinforcement. Patte's somewhat obsessive interest in

building techniques emerged somewhat later, in 1767, with a letter in the Annee Litteraire attacking current building practices in Paris, and, in the same year, in his first Memoire sur Vachievement du grand portail de

Veglise de Saint Sulpice. He was, as is well known, hoping to win the com? mission for himself. He certainly discussed the use of iron reinforcement in the lintels of that facade, but his fuller and more influential investi?

gation of the subject came two years later, in 1769, in the seventh

chapter of his Memoires sur les objets lesplus importantes de ̂ architecture, a chapter, of sixty pages, entitled 'Parallele des meilleurs moyens usites,

jusqu'ici, pour construire les plate-bandes, et les plafonds des colon? nades'. This is the first and also the fullest account of iron reinforcement to be published in the eighteenth century, and even J. B. Rondelet, in his Traite theorique et pratique de Vart de hatir of 1802, was to rely almost

entirely upon it. Patte described how Perrault, following the example of the Roman

'Piliers de Tutuelle' that he had seen in Bordeaux (Fig. 1), used relieving arches to lighten the load on the entablatures on the Louvre (Fig. 2), in

particular in the pediment, but there remained the technical difficulty that lintels in France must be built up with voussoirs ('claveaux' was the

eighteenth-century term for these stones, 'voussoirs' being reserved then for the tapered stones used for vaults). The stones of France could not

provide the spans that the ancients had achieved with marble. With the

development of a style of architecture that was more consciously antique, a technical resolution of the difficulty had to be found. Per rault's brilliant and daring solution was to introduce iron reinforcement

throughout. He was the first, Patte held, to introduce it on this scale. The very arrangement of coupling the columns at the Louvre, Patte

thought, was designed to achieve greater stability. A metal bar was

placed in the centre of each column to ensure coherence and to anchor the two bars that were threaded through the upper part of the front entablature and linked back, through a further system of bars set in the

beams, to the wall behind. Each bay was further stabilized by two cross?

bars, forming an X. The bars were all about two inches square in section. The voussoirs of the front entablature were linked to one another with

independent Z-bars ? sheer links, we would now call them. There is a lot more by way of detail in Pane's description, though nothing by way

54 AA FILES 9



of structural theory other than the remark ? certainly of significance ?

that the aim throughout was to use iron in tension: 'Ce me paroit prin cipalement donner une force inebraniable ? sa b?tisse, c'est que le fer ne

porte rien et ne fait exactement que la fonction de tirer pour retenir la

poussee des architraves et solider] Taxe des colonnades; procede qui doit necessairement prod?ire la plus grande resistance que Ton puisse esperer de la part du fer' (p. 273).

Patte illustrated and described at similar length the arrangement of the iron reinforcement in A. J. Gabriel's colonnades on the Place Louis XV

(Fig. 3) and the second order of J. N. Servandoni's portico at Saint

Sulpice (Fig. 4) ? he did not know what arrangement had been adopted

for the first order. Both buildings had been the responsibility, he noted, of Besnard (who worked also on Gabriel's Ecole Militaire), and it is evi? dent that Patte consulted him on the details of erection. Indeed Patte hints at an even greater degree of participation in the Place Louis XV:

1. P. Patte, Memoires sur les objets les plus importants... (1769), Plate XII. Fig. 5 shows a detail of the construction of the Piliers de Tutuelle'at Bordeaux, as recorded by Charles Perrault. Figs. 6, 7,8 show details of an arrangement of reinforcement designed by Patte.

2. P. Patte, Memoires sur les objets les plus importants... (1769), Plate XIII. Plans, sections and elevations detailing the iron reinforcement of the Louvre colonnade by Claude Perrault.

'Comme j'ai ete temoin de toutes les attentions que Ton a apporte pour operer la perfection de cette construction, j'espere qu'on me scaura gre d'entrer dans tous les details' (p. 278). His greater knowledge of struc? tural details is in evidence throughout this section, but it serves only to show that though there was more complexity in the reinforcement on the Place Louis XV ? the various bars in the entablature were, for

instance, more systematically linked together to form a coherent frame? work ? there was as yet no theory of mechanics to account for the

design. Similarly, at Saint Sulpice, though the superimposed orders made far more problematical the achievement of stability, and in con?

sequence more elaborate than ever before the design of the reinforce? ment ? with a flat curved bar in compression introduced by way of a

relieving arch between the tie-bars emerging from the cores of the columns ? there is no evidence that a coherent theory of mechanics sus? tained the design.

iWP'V7 if J H

AA FILES 9 55



None the less, having dealt with three lesser examples ? the portico

by Pierre Desmaisons for the Theatin church in the Rue de Lille (1747), that on the north front of the Palais Royal, and another, in brick,

designed by Lamotte for Saint Petersburg?Patte did offer some general guidelines for architects embarking on such construction: 'Comme je suis persuade que Ton peut raisonner la construction des plate-bandes egalement comme celle de toutes les autres vo?tes, je crois devoir

developper ma pensee ? ce sujet' (p. 314). He offered a design of his own

by way of demonstration.

Firstly, columns must be designed to bear the weight of the entab? lature and any walling or vaulting above (he referred here to J. R. Per ronet's calculation of the resistance of stones based on measurements

taken of the columns in the thirteenth-century refectory of Saint

Martin-des-Champs). Secondly, a single entablature, with deep vous?

soirs, was to be preferred to superimposed layers of beams, as was more

common in practice ? and cheaper. The voussoirs might be linked

together with independent Z-bars. As to any reliable calculation of the

breaking-strength of iron, he could offer no certainty. Buffon had car?

ried out a number of experiments and tabulated his results in L Art du serrurier (pp. 8-9), but it was evident that the qualities of iron varied

greatly and that any increase in cross-section did not necessarily lead to a proportional increase in strength, the very process of making larger sections often leading to a decrease in strength through successive re

heatings. The only certainty was that the eye or anchor fixing the horizontal reinforcing bars to the vertical ones was likely to be the weakest point, and these anchors were weaker when formed as a square than when simply curved. The reinforcing irons might be painted with two coats of oil paint to prevent rust, though many considered this un?

necessary, the whole being regarded as waterproof anyway; the bars

might, alternatively, be coated with lead or, as at Saint Sulpice, wrapped

3. P. Patte, Memoires sur les objets les plus imortants... (1769), Plates XIVand XV. Plans, sections, elevations and details of the iron reinforcement of the buildings on the Place Louis XV(Place de la Concorde) by A.]. Gabriel.

opposite page:

4. P. Patte, Memoires sur les objets les plus importants... (1769), PlateXVI.

Figs. 1,2,3: details of the iron reinforcement of the second order of the west front of Saint SulpicebyJ.-N. Servandoni.

Figs. 4, 5, 6: details of the iron reinforcement of the portico ofSainte A nne by Pierre

Desmaisons.

Figs. 7, 8, 9: details of iron reinforcement ofthe north portico of the Palais Royal by Constant-d'Ivry.

Figs. 10,11,12: details of the iron reinforcement of a brick entablature built at Saint Petersburg to the design ofM. de Lamotte.

56 AA FILES 9



in bitumenized hemp (filassegaudronnee). In general iron was to be con?

sidered as a safeguard rather than a basic means of construction, and it was to be used in tension rather than in compression (Perrault's arrange? ment at the Louvre thus being preferable to Servandoni's and Gabriel's) and, most important of all, the reinforcing bars should be placed at the bottom of the entablature. Doubling them up was to no great purpose, he believed, as the vertical rods within the columns could not be cor?

respondingly duplicated and the joint there thus remained a point of weakness. On the whole Patte's analysis, if restricted, was sound,

though curiously he could not see the point of the cross-bracing Perrault had introduced at the Louvre. When Patte was required to take up these considerations once again, in the sixth volumne of J. F. Blondel's Coursd'architecture, published in

1777, he simply referred his readers back to the Memoires (Cours, VI,

p. 165), though he did describe the reinforcement in the Louvre pedi? ment and, when reproducing his places from the Etudes, indicated the

position of the iron there for the first time (Cours, VI, pp. 164-170, pi. 105-7). Likewise, as already noted, when J. B. Rondelet dealt with these

matters in UArt de Batir in 1802, he relied for his information on Patte's Memoires sur les objets les plus importants ... His illustrations derive

directly from Patte. Though Rondelet was able to add to his range of

examples the portico of J. G. Soufflot's Sainte Genevieve, with which he himself had been directly concerned. The construction of this great church and the polemic it stirred have been so thoroughly analysed in recent years that any further consideration is surely unnecessary, suffice it to note that, despite all the experiments conducted by Soufflot and his

associates, Rondelet was able to provide no evidence in his treatise of any

enlarged understanding of the mechanical properties of reinforced lintels. Patte's analysis was not yet superseded, even in Rondelet's

greatly revised edition of UArt de Batir, of 1834.

But Patte, it is now apparent, was not the only theorist of iron re?

inforcement in the eighteenth century to set down his ideas. A manu?

script, with pages numbered 1 to 139 and with 37 finely drawn plates, the whole clearly intended for publication, has recently been found in Paris ? 'Essay en forme de traite sur la construction ou Ton propose une

portion d'eglise pour modele avec une observation sur les parties de con?

struction que ne sy rencontrent pas'. This was in the library of the archi? tect Pierre II Rousseau, designer of the Hotel de Salm in Paris, when he died in Nantes on 24 September 1829, at the age of 78. It was purchased then by the Directeur de l'Ecole des Freres de la Doctrine Chretienne and given to a local architect, Lassay. The assumption has been that it is the work of Rousseau. Though it might indeed have been copied out by him, and though he might have contributed something to it, it is more

likely to be the work of his father-in-law, Nicolas Marie Potain (1713 1796), admired by C. N. Cochin, it should be remembered, alongside Soufflot, for having effected 'un retour d'un meilleur goust' (Memoires inedits ... (1880), pp. 141-2). The architectural details in the illustrations are more old-fashioned than one would expect from Pierre Rousseau, as are the published sources referred to in the text ? J. F. BlondePs Cours d'architecture (1675-83), J. B. de la Rue's Traite de la coupe despierres (1738-9), and Robert Pitrou's Recueil de differentsprojets d'architecture de

charpente ... published in 1756 by the engineer Tardiff ? but more

important is the fact that a draft manuscript on construction by Potain was being read by the members of the Academie d'Architecture on 1

February 1762 (P. K, VII, p. 89). A few years later, in 1767, Potain pub? lished Traite des ordres d'architecture, described as the first part of a more

comprehensive treatise. If the present manuscript is indeed a part of this intended work ? and mention is made in the Traite des ordres of yet another section to follow, on timber construction ? one may assume

that its non-publication was owing to the fact that it was rendered

AA FILES 9 57



redundant with the publication, in 1769, of Patte's Memoires sur les

objects les plus importants... Many of the subjects treated in the manuscript relate to Potain's

known interests and activities. He was A. J. Gabriel's 'premier dessin ateur' from 1748 onwards, working at Versailles and Fontainebleau, in

charge of the buildings on the Place Louis XV from 1754 to 1770, and, from 1768, for four years, of the work at the Ecole Militaire. In 1763 he succeeded Soufflot as architect of the cathedral of Rennes, where he

designed a basilical church with free-standing columns between the nave

and aisles, that was started only in 1786, to a revised design by Mathutin

Crucy, and in 1764 he was commissioned to build the church of Saint

Germain-en-Laye, another basilical church with free-standing columns, that was begun in the following year, but soon suspended and taken up

again only in 1787 and continued for four years. His son-in-law, Pierre II Rousseau, was involved with this church. The present building is by

A. J. Malpiece and A. J. Moutier, who erected it in 1823 and 1824. The manuscript illustrates ? and these are the only known illus?

trations of this ? the arrangement of the iron reinforcing in the archi? traves of the chapel at the chateau of Versailles. Potain, as Gabriel's

'premier dessinateur', had access to such information. The manuscript is chiefly concerned with free-standing columns, several of the designs illustrated might thus relate to early proposals for Rennes or Saint

Germain-en-Laye. Finally, the last illustration in the manuscript describes the workings of the three-storey lavatory-block at the Ecole

Militaire, the building of which was in Potain's own charge. It is thus not altogether unreasonable to assume that the notions and information contained in the manuscript date from the mid-1760s and that their author was Potain?though the present copy might have been the work of his son-in-law, Pierre II Rousseau, in whose possession it was in 1829. The treatise appears to be the first on iron-reinforced construction.

58 A A FILES 9



6. P. Potain?, MS 'Essay enforme de traite sur la construction9, ? ^ Plates 10,11,12. Plan and details of ironwork and cross-section

showing the irm-reinforcement system ofthechapelat Versailles ^^^Hh^^^^ÎH^^^^^^^^^^^^^^^^^^^^Î^^H^^m adapted for use in the model church.

^XlflfilaEfflB^^ '.III Ml 1 11 ? : ?' v ti j Iii'11 M iilliMtnX MM

ÎIIpBB^^m^m

59 This content downloaded from 130.63.180.147 on Tue, 19 Aug 2014 20:30:30 UTC

All use subject to JSTOR Terms and Conditions


That, certainly, is the claim of its author: 'peut-etre le premier essay qui ce soit donne en forme de traite sur une matiere aussy serieuse qu'inter ressant' (p. 1). The guiding aim ? which is to be expected in the middle

years of the century ? was 'une attention suivie a tout ce qui peut con

tribuer a la solidite, sans trop de pesanteur* (p. 3). The essay begins with a consideration of the qualities of lime, sand and

stone, with recommendations for their application. Remarks of this nature had already appeared in engineering treatises and were to become even more familiar in the writings of Patte and, later, Le Camus de

Mezieres ? see, for instance, Le Guide de ceux qui veulent batir, of 1781. Next came the examination of site conditions ? ascertained through trial holes ? and the setting-out and laying of foundations, whether on

timber piles and rafts or with inverse arches of stone or cellars. The

building of walls follows ? with a recommendation that hard stone be used up to six feet, at least, and for all heavily loaded areas. The model to which reference is made throughout is a section through the nave, aisle and side chapel of a church, with flying buttresses over and vaults of stone or brick (Fig. 5). Timber was to be dispensed with. More than half the treatise ? seventy pages and more ? is given over to possible vari? ations in this construction, in particular to the method of reinforcement for the architraves of stone set above the free-standing columns. The

free-standing column, one should note, is the only support considered

acceptable between the nave and the aisles. Three basic methods for plac? ing the iron reinforcing bars are described and analysed: first, as at Ver?

sailles, with the bar put in a channel on the underside of the voussoirs, concealed by a fillet of stone, or plastered (Fig. 6); second, as in the Louvre colonnade, with the bar set above the voussoirs with indepen? dent Z-shaped sheer links between the voussoirs (Fig. 7); and, third, as in the first and second order of Saint Sulpice, with bars top and bottom linked by ties between the voussoirs to form a rigid frame (Fig. 8). The

arrangement over the first order is described as the strongest of its sort in

France, but only that over the second order, less complex, is illustrated. It is not quite the same as that shown by Patte. The curved bar acting as a relieving arch is not included. Each of the three methods illustrated, it is important to note, is shown not in its original position

? that is, at

Versailles, the Louvre or Saint Sulpice ? but as it would be if adapted for

use in the church chosen for a model, which might account for the

discrepancy between Patte's Saint Sulpice arrangement and that shown here. Three further variations for iron reinforcement are offered, each

involving the use of parallel reinforcing bars set in the underside of the

architrave, each with progressively fewer related bars and simpler joint? ing. The last, the simplest of all, is the most efficient (Fig. 9). The remaining section on iron reinforcement deals with the problem

of setting the face of an architrave flush with the front of a column, a

hazardous, visually disturbing operation which provides the occasion for theoretical remark (p. 91):

nous ne sommes plus dans ces temps ou plus une construction paroissoit sur

prenante, plus elle etoit belle; c'etoit le principe de ̂ architecture gothique. L'on est cependant tente de croire qu'ils etoient meilleures constructeurs que nous, en

ce qu'ils metoient toutte leur etude a masquer

les forces dont-ils avoient besoin,

pour que le rest de Pedifice paroit d'une legerete incomprehensible. Notre architecture au contraire, non seulement requiert de la solidite, mais il

faut encore que cette solidite soit apparente, ainsy toutte construction qui ne

tranquilisera pas le spectateur sur cet article, pechera contre les principles recues.

Jacques-Francois Blondel held to much the same opinion. There is more, in the chapter on lightweight vaulting and roof construction ?

the new flat-brick system of vaulting being preferred here to all others ?

with reference to Gothic architecture, and it is of some significance that the chapel at Versailles is judged superior in audacity and lightness of form to any of its Gothic precursors. Gothic architects, the author says,

60 AA FILES 9



disguised the forces involved in their buildings by using flying but? tresses. 'Malgre cette pratique dans leur execution/ he continues, 'on n'en voit point d'aussy legere que cette chapelle; on peut la regarder avec

juste raison comme un chef d'oeuvre de construction, quoy que plusiers edifices gothiques paroissent plus legers, en les examinant Ton trouvera

qu'ils le sont beaucoup moins que celuy cy' (p. 106). That, to all intents and purposes, is the final summation. The remain?

ing pages of the manuscript are devoted to short comments on the mak?

ing of roof terraces, balustrades, embankments and quays, sewers and lavatories ? those in particular at the Invalides and the Ecole Militaire. The essay reflects faithfully the concerns of mid-eighteenth-century

theorists ? a desire for elegant and economical construction based on a

close study of Gothic, but conceived in a form that is rigorously antique, in the image of ancient Greece. Greek architecture, though virtually unknown, is regarded fixedly as the fountainhead ? 'Les Grecs que nous

regardons comme les peres de Parchitecture, et dont nous suivons les

principes' (p. 43). The incompatibility of these two systems of archi? tecture was to be resolved by means of the latest technical refinements ?

arches and vaults of lightweight brick and tile construction (the Comte

d'Espie's Maniere de rendre toutes sortes d'edifices incombustibles ou traite de la construction des vo?tes faites avec des briques et du pl?tre, which set the fashion, was published in 1754) and also, as I have emphasized, iron reinforced lintels (Fig. 10). The building in which these new ideals and

expertise were to find expression was the church ? the colonnaded basilical church that appeared in France around 1764 and became

increasingly popular in the years that followed: Potain's churches for Rennes and Saint-Germain-en-Laye, L. F. Trouard's Saint Pierre at

Montreuil, and, best known of all, J. F. T. Chalgrin's Saint Philippe-du Roule, in Paris. The model offered in the manuscript might, as already noted, relate to Potain's early projects, though it is worth remarking

& P. Potain?, MS 'Essay en forme de traite sur la construction ', Plates 16,17. Sections and details ofthe iron-reinforcement system ofthe west portico ofSaint Sulpice adapted for use in the model church.

7. P. Potain?, MS 'Essay en forme de traite sur la construction', Plate 14.

Sections and details showing the iron-reinforcement system of the Louvre colonnade adapted for use in the model church.

AA FILES 9 61



that it is close in style and detail to J. B. Le Brument's design, of 1767, for the Madeleine at Rouen, where work was begun in 1773 and where Patte was called in, in 1774, to provide expert advice on the cause of the

cracking and spalling of the stones of the portico. The master-mason was

Pierre Pradeaux; his assistant for the iron-reinforcing was Le Trone, who had already worked on the towers of Saint Sulpice. Patte seems to

have been involved, in different ways, in almost all the iron-reinforced

buildings of the mid-eighteenth century. The brief summaries of Patte's Memoire and the unpublished manu?

script that I have offered make clear, I hope, the way in which architects, however much they might be concerned ? obsessed even ? by con?

struction, were conditioned by their training. They were determined

throughout the eighteenth century to achieve an orthogonal architec?

ture, an architecture based on the more or less static relationship of sup? port and load. They wanted columns and lintels. Though they relied on

an analogy with Gothic construction to allow for all lightness of con? struction and all whittling away of mass, they were quite willing to

disregard the dynamic nature of the Gothic system, which, as is well

known, they understood tolerably well. Their structural bravura was

altogether determined by their aesthetic aims, not by any real grasp of

engineering principles. In the early 1770s, as Jacques Heyman has recently shown, when Patte

and Emiland Gauthey were disputing the structure of Sainte Genevieve, Patte was unable to grasp the concept of inclined forces within the dome. Gauthey, the engineer, shared Patte's aesthetic aims, but he was

willing and able to envisage alternatives based on engineering par? ameters. Gauthey demonstrated that the four supporting piers of Souf flot's dome could, in mechanical terms, be altogether eliminated, pro? vided that raking buttresses were designed to carry the thrusts right down to the ground. Later, in the 1790s, the dispute concerning the

''^^^

:' f''^^"' ? *construction', Plate 25. Details and sectionsof a proposed

T/777T.~M^fl f ///A I X\Y\T '

i 62 A A FILES 9



dorne of Sainte Genevieve still unresolved, Rondelet, whom one is inclined to think of as an engineer rather than an architect, so heedless

was he of formal values, revealed himself just as limited in his outlook as Patte. In his famous Memoire of 1797 he determined to prove that

spherical domes do not thrust. He was unwilling, perhaps unable, to

comprehend Gauthey's arguments. Gauthey had to rebuke him, rather

rudely, in a Memoire of the following year. In the successive committees set up in 1796 and after to report on the structure of Sainte Genevieve, there is this same split in comprehension

? the engineers are divided

firmly from the architects. The engineers, with Gauthey at their head, have an understanding of the mechanics of the structure; the architects, with Rondelet at their head, can conceive of the structure only within the frame of reference provided by their formal training. They see it in terms of load and support, the column and lintel.

Curiously, even when we move some years on, into the nineteenth

century, we find much the same pattern of thinking. Aesthetic sen?

sibilities have changed by then. The urgent dynamism of Gothic con?

struction is appreciated as never before and upheld above all else ?

especially the column and lintel. Viollet-le-Duc villifies Vignon's Madeleine in his Entretiens. He rejects what he recognizes as makeshift construction of iron-reinforced lintels, and himself proposes a radical new architecture based on a study of Gothic structural principles (his

knowledge of Gothic structure, it must be stressed, scarcely, if at all, in

advance of that of Perronet or Gauthey) which involves raking mem?

bers of iron for support. His designs are all too well known. But though they purport to derive from the dictates of structural principles, they are

no more mechanically efficient than the designs of Potain or Patte.

Viollet-le-Duc knew engineers such as Polonêau and Eiffel?though he seems to have fallen out with Polonêau owing to the lack of publicity he received for his work on the imperial train ? but he seems not to

10. P. Potain?, MS 'Essay en forme de traite sur la construction \ Plates 30,31. Sections showing the vaulting and roofcoveringfor nave and side aisles achieved with the use of stone arches, stone slabs and/or tiling obviating the use oftimber.

AA FILES 9 63



have consulted with them on engineering matters. Indeed, it was Eiffel who asked advice from Viollet-le-Duc on the mix for the bronze mantle for the Statue of Liberty. All Viollet-le-Duc's iron members are hope? lessly oversized. They are the outcome not of an understanding of the

mechanical principles of Gothic construction or the structural prop? erties of iron; they are based on his aesthetic delight in the raking stone forms of Gothic architecture (Figs. 11,12). Architects, as we know, do not make good engineers; even the most

hardened of them prefer aesthetic to technical realities.

References

Guillerme, J., 'Soufflot, Sainte Genevieve et les limites de l'invention technique', in

Soufflotetson Temps, exhibition catalogue, edited by M. Gallet etal. (Paris, 1980),

pp. 154-66.

Heyman, J., 'The crossing piers of the Pantheon', to be published. Lemonnier, H., Proces-verbaux de l'Academie Royale d'Architecture 1671-1793 (Paris,

1911-26). Mathieu, M., Pierre Patte, sa vie et son oeuvre (Paris, 1940). Mouilleseux, J.:P., 'L'Eglise de la Madeleine ? Rouen: Un example du debat theoriqiie

de l'architecture sacree au temps de Soufflot', in Soufflot et ̂architecture des lumieres, edited by M. Mosser and D. Rabreau (Paris, 1980).

Wilcox, R. P., Timber and Iron Reinforcement in Early Buildings (Society of

Antiquaries, London, 1981).

11. Viollet-le-Duc, (Arc\ in Dictionnaire raisonne de Yarchitecture francaise

(1854-68), Fig. 54. Flying buttress, Chartres Cathedral.

12. Viollet-le-Duc, 'Douzieme entretien'(1872), Fig. 18. Vaulted chamber.

64 A A FILES 9



Documents

AA - Architects as Engineers in 18thC France