Post date: Oct 29, 2015 6:59:57 PM

The following is a talk given in October 2015 by Edwin Trout of the Concrete Society and preproduced with his kind permission.

Bow Bridge, Wateringbury

and the development of early reinforced concrete

by Edwin A.R Trout,

to mark the centenary of Bow Bridge, 7^th October 2015

Bridges, being largely horizontal and unsupported structures, are more or less by definition subject to the forces of tension as the deck flexes under load. They depend on the intrinsic properties of the building material to resist these forces over short spans – perhaps relying on piers for intermediate support, as in the monolithic slabs of the mediaeval clapper bridge – or are designed as arches to transfer the weight of loads in compression, such as would be the case in a traditional masonry bridge. The use of timber, and in the nineteenth century, iron, has extended the possibilities of design, but not averted the challenge of achieving long spans.

In the nineteenth century, however, a new material was developed. Concrete was initially reliant for its binder on hydraulic lime or Roman cement, then increasingly on Portland cement. As strength improved so emerged the possibility of its use in structural applications so familiar today (as apposed to its early application as stucco, mouldings or infill). But though concrete is strong in compression it is weak in tension, and so unless it was simply to replicate masonry, it was liable to fail in spans of any length. To extend its use, stiffening it with iron – which is strong in tension – was explored and developed throughout the second half of the century.

The developing idea of reinforcement

Pioneers of iron reinforcement in England and France

The idea was not entirely new – the ancient Romans used bronze tie rods, and iron chains were used for restraint in masonry construction in the eighteenth century France; also by Semple and Smeaton in the British Isles. But in a cementitious context, one of the earliest published suggestions of reinforcement was by J.C. Loudon in his Encyclopaedia of cottage, farm and village architecture (1830) in which he proposed the construction of flat roofs comprising a lattice of iron tie rods embedded in cement and topped with tiles. [Kempton Dyson; Addis & Bussell, p.22] It was an idea that was to exercise the minds of engineers in Britain and France for years to come.

In the 1840s, following a strike by carpenters and its consequences for timber construction, two systems arose in the French capital: the Vaux and Thausne systems in which rods were threaded through, or suspended from, iron joists. In each the reinforcement was encased in plaster of Paris, which, however, caused the iron to rust and in time both systems fell from favour [Kempton Dyson].

Of longer-lasting impact was the promotion of the fire-resisting qualities of cement-based concrete, or mortar, which reached its classic form in the so-called fire-proof floors patented by Henry Hawes Fox in 1844 and marketed under the Fox & Barrett brand. By the terms of this patent, iron joists were encased in lime concrete and in-filled with concrete vaults, variations of the design of which became widespread as the century wore on and were known as ‘filler joist floors’. It is probably fair to say, however, the principal purpose at this stage was to retard the passage of fire in a building rather than to enhance the structural performance of the floor by this combination of materials.

In England another, stronger and more durable type of binder than plaster of Paris was being developed in the 1840s: Portland cement. Patented by Joseph Aspdin in 1824, the inventor’s son William improved the production process and took up its manufacture in Kent before transferring to Gateshead in 1852. There his path crossed with that of a Newcastle plasterer named William Boutland Wilkinson, who found a practical application for the new material in “the construction of fire-proof dwellings”, as popularised by Fox & Barrett. It was his method of supporting the concrete floor that is of interest here. By a patent dated 27 October 1854 he described a method of reinforcing concrete placed between plaster moulds to form monolithic suspended floors and related building elements. The phrasing of the patent suggested he may have understood the means by which the reinforcement resisted the tensile stresses placed on the slab, with wire ropes looped up at the ends for anchorage. Alternatively, the ropes may be seen rather as a form of suspension supporting the infill [de Courcy]. A modest house built in 1865 demonstrating a development of Wilkinson’s approach, with concrete reinforced by steel colliery ropes, was thoroughly investigated by Professor W. Fisher Cassie before its demolition in 1955. [Cassie]

While Wilkinson indicated an understanding of embedded iron’s resistance to tension, other pioneers’ contributions to the emerging idea of reinforcement were, though better publicised, ambiguous in their demonstration of iron’s function. Joseph Lambot’s famous boat made in 1848 of wire mesh and cement mortar, was patented and displayed at the Exposition Universelle of 1855, and the gardener Joseph Monier made flower tubs of a similar combination of materials in 1849. Though the motive was not, in either case, fire protection, the iron was at this stage mainly a passive means of carrying the mortar.

A more immediately significant development came from the contribution to concrete construction made by Francois Coignet. A chemicals manufacturer by occupation Coignet spent the late 1840s experimenting with a form of concrete which he termed beton agglomere, before turning to the addition of iron. Having erected a factory for his chemicals business at St Denis, Paris, in 1852, he built a house opposite of monolithic concrete for which the flat roof was strengthened with iron beams. He then proposed a flooring method by which cast iron stop planks were interlinked by iron rods fastened with a nut at each end. These secured the walls in the vertical, acting as an internal alternative to external buttresses, but their use did suggest an awareness of the need for permanent tension members to be incorporated in the slab. His British patent of 1855 (followed by a French one a year later) was for “artificial stone and cement”, and its value lay more in the process of mixing and compaction of concrete than in its reinforcement. Nevertheless Coignet exhibited at the Exposition Universelle and built several houses that demonstrate his confidence in the method. One of them, incidentally, in the Rue de Poissonniers, was dissected 50 years later and the reinforcement found to be rust free. He went on to become a successful contractor in concrete building, publishing a monograph in 1861 and capturing the attention of Emperor Napoleon III. But though he incorporated iron supports in his concrete buildings, he made no further advances in the understanding of reinforcement and failed to transform building practice in France. His example was well received in Britain where concrete was actively employed by architects and contractors in the late 1860s and early 1870s, though generally without reinforcement. Charles Drake bonded his concrete with hoop iron from 1868, Philip Brannon patented a system of monolithic reinforcement in 1871 and ‘74, and Henry Lascelles embedded iron rods in his precast concrete housing slabs from 1875. But though there was an awareness of the strengthening effect of iron, many distrusted or even disapproved of combining it with concrete. A Mr Robins even incorporated gum to ensure the iron and concrete stuck! [Collins, p.50]

Early experiments in the UK and USA during the 1870s and ‘80s

As French and British progress in concrete construction began to founder in the 1870s, so interest in the possibilities of reinforcement was taken up by several Americans with an eye on recent practice in England. Foremost among these were W.E. Ward, Thaddeus Hyatt and Ernest Ransome. William Ward (1821-1900), when visiting the UK in 1867, was inspired by seeing the difficulty with which British labourers removed cement from their metal tools and so set about investigating the action of iron in concrete as a medium of construction. He experimented in 1871 and 72 on concrete beams reinforced with iron joists, seeking “a properly adjusted combination of their special qualities”. Importantly he concluded that iron should be placed near the bottom of a beam “to utilize its tensile quality for resisting the strain below the neutral axis”.

His compatriot Thaddeus Hyatt (1816-1901) also visited the United Kingdom on business and was prompted to experiment with reinforced concrete, the results of which he published in 1877 as An account of some experiments with Portland-cement-concrete, combined with iron, as a building material … This paper sought not only “security against fire”, but “economy of metal in construction”. The tests he commissioned at David Kirkaldy’s laboratory demonstrated that concrete’s compressive action above the axis was more than sufficient to counter the tensile stressing of the iron bars below, and he concluded that economies could be made in the quantity of metal needed. Temperature tests demonstrated that the expansion of iron and concrete were similar and that resistance to fire was related to time. Hyatt foresaw numerous other developments in reinforced concrete, but, loosing interest after lodging a patent in 1878, failed to develop any momentum for the material’s adoption. However, Ransome later argued that Hyatt’s patent “describes everything necessary for the pratical use of reinforced concrete.”

Ernest Ransome (1844-1912), of the Ipswich iron foundry and machinery dynasty, had gone out to America in 1869 to develop his father’s artificial stone business and settled in San Francisco as the superintendent of the Pacific Stone Company in 1870. He soon set up a factory to manufacture concrete blocks and after a period of experimentation and discovery, pioneered a series of technological innovations in mixing equipment and reinforcement. His first patent, for square-section iron bars, was awarded in 1884 and it became the cornerstone of the eventual ‘Ransome System’. For this he developed a special machine to twist the bars, up to 2” in diameter, to the shape that he found conferred a greater tensile resistance than conventional round bars. His patent soon found practical expression. He built the Arctic Oil Works in San Francisco, then experimented in 1886/7 with two small reinforced concrete bridges in the Golden Gate Park. Of these the Alvord Lake Bridge still bears a plaque as a National Historic Civil Engineering Landmark. Other structures followed, including the Art Museum, Stanford University (1893) and Pacific Coast Borax factory, Bayonne, NJ (1897). In 1902 his final patent allowed full-scale factory frame construction using the combination of exposed frame and curtain wall, soon to be “the workhorse of the new industrial architecture”.

Other British and American innovations marked this period of progress, with patents lodged by: W.H. Lascelles (1877), J.J. Jackson (1877), J.C. Golding (1884), W.H. Lindsay (1885), William Simmons (1885-86), Lee & Hodgson (1885) and W.H. Briggs (1889). [Kempton Dyson]

Scientific development in Germany

However, the main thrust of practical progress manifested itself in the German-speaking lands, taking inspiration from the later work of that unlikely inventor, the French gardener, Monier. Joseph Monier (1823-1910) eventually patented his reinforced concrete flowerpot design in 1867, and as his ideas developed he took out further patents in the years to 1877. His final patent represents one of the seminal moments in the development of reinforced concrete, coming as it does so close to the date of Hyatt’s publication and the start of Hennebique’s experiments. But though he had little grasp of the real role of reinforcement – when corrected by later investigators, he resorted to blustering, “who is the inventor, you or I?” – the value of his ideas lies in their adoption and development in Germany.

The rights to Monier’s patent in the southern German states were purchased in 1884 by the firms of Freytag & Heidschuch of Neustadt and Martenstein & Tosseau of Offenbach. A year later the engineer G.A. Wayss took the licence for Prussia and the other northern states of the German empire. (Rudolph Schuster made similar arrangements for the Austro-Hungarian empire.) Taking the lead in promoting the new method of construction, and later buying out his rivals to form Wayss & Freytag, Wayss commissioned a programme of experiments into strength, fire-resistance and corrosion. Load tests, to which other engineers and government officials were invited, were held in public. He published the results provisionally in 1886, then in 1887 as the book Das System Monier, with a theoretical exposition by the government engineer Mattias Koenen. This was the first published attempt at a scientific explanation of reinforcement’s behaviour based on systematic test results. Though he erred in the basis of some of his calculations, Koenen subsequently corrected his misconceptions in Outlines of the statistical calculation of concrete and reinforced concrete constructions (1902). Other engineers became interested in the results of Wayss and Koenen’s investigations – Franz P. Meyenberg, for instance, introducing the first loose stirrups in beams 1891 [Kempton Dyson] – and the adoption of reinforced concrete proceeded rapidly throughout central Europe. Its progress was characterised by the acceptance of commercial quality control, industry standards and official regulations, but an account of that lies beyond the scope of this paper.

In attributing the commercial success of reinforced concrete in the 1890s, the Scandinavian engineer Suenson identified the contribution of two men above all: “the engineer Wayss in Germany and the contractor Hennebique in France”. In the original Danish, Hennebique is described rather as “Entreprenor”, which is probably a more accurate description, and it was his commercial dominance in the market that restored to France its technological lead.

French patents of the 1890s

After Coignet’s commercial isolation in the late 1860s and failure at the time of the Franco-Prussian War, the French market had indicated little appetite for concrete construction. Nevertheless, several innovators experimented with reinforcement in the 1880s and emerged into public view at the end of the decade. Paul Cottancin, for instance, was granted a patent for a continuously woven mesh-type reinforcement in 1889 and went on to be commercially active until 1906 [Edgell]. Edmond Coignet (1853-1915), son of Francois, demonstrated in 1889, to the Societe des Ingenieurs Civils de France, the principle that “it is desirable to leave as much space as possible between the metal which takes the tensile stresses and the concrete which takes the compressive stresses”. He was awarded a patent for reinforced concrete pipes and tunnels in 1890. His proposal of reinforced concrete for the Paris drainage system was accepted in 1892 and proved to be something of a catalyst; he built the casino at Biarritz that year and his patent for beams was published later in 1892. Another for piles and sheet piles followed in 1894. 1894 also saw Armand Considere (1841-1916) commence his research into columns that led the application of spiral reinforcement for concrete in compression, and later introduced expansion joints in long bridges and wharves [Steinberg p.93]. But it is with Hennebique and the exploitation of his initial 1892 patent that we are mainly concerned here. As Monsieur N. de Tedesco, the contemporary editor of Le Ciment, asserted: “until 1892, very few important works of reinforced concrete … were undertaken in France” [Tedesco].

Francois Hennebique (1842-1921)

Hennebique was born at Neuville-St-Vaast, in the Pas-de-Calais region, and appeared destined to cultivate the family landholding. However, he showed an early aptitude for science and nurtured an interest in its practical application in construction. He became apprenticed to a stonemason in Arras while continuing theoretical studies in his spare time. Having been entrusted with the reconstruction of a church he set up in business, at the age of 25, as a contractor specialising in church restoration. His interest in the possibilities of reinforcing concrete came about in 1879, when designing a house in Lambardzeyde for a client who was concerned about the potential for destruction by fire and so was using a type of filler-joist floor. He realised that the use of iron joists was wasteful and thought that higher quality steel in tension, combined with concrete in compression, would be more efficient. His scientific studies suggested placing the steel at the bottom of the concrete beam and he successfully load-tested a mock-up in his yard. The house was completed in 1880 and served satisfactorily until its destruction in the Great War. Success prompted further experiment and the 1880s were devoted to perfecting his methods, which soon included the use of stirrups. An article outlining American developments appeared in the French technical press in 1892, the year also of Coignet’s drainage contract, and accelerated Hennebique’s application for the first of the patents he was to protect so jealously over the ensuing decade or so. The first patent was for beams, effective in both France and Belgium, and was followed in 1897 by one for bent-up bars and in 1898 for the ‘V’ stirrup. During these years he developed a system in which the various components would comprise a completely monolithic structural frame.

With the publication of his 1892 patent Hennebique withdrew from contracting on his own account and set up a new business, the model of which was perfect for the purpose. Hennebique’s office would design and prepare drawings for the reinforcement, and supervise the concreting work, which, to ensure quality, would be undertaken by licensed contractors appointed and accredited by him. These contractors, chosen and retained for their competence, would be free to work elsewhere during slack periods, but could be expanded when demand required and would pay a royalty fee for the privilege of using the newly fashionable Hennebique system. Agents were appointed to seek new business in the regions and, in due course, abroad. His first national office was established in Brussels, but others followed as the use of ‘Beton arme’ grew. The Swiss engineer Edward Zublin was one such agent, operating in the then German province of Elsass-Lothringen (now Alsace and Lorraine) where in 1899 he was responsible for the monumental Rheinhafen buildings.

In 1894 Hennebique designed his first reinforced concrete building, a modest single-storey structure for the Raffinerie Parisienne de Saint Oven, but followed it in 1895 with two landmark buildings, the spinning mills at Tourcoing and Fives, each with extensive glazing between the reinforced concrete frame elements to allow plenty of working light – a valuable additional benefit to that of fire-resistance, economy in materials and savings in construction time. A highlight was the headquarters he built for his firm at Rue Danton in Paris. Maison Hennebique was a showcase for reinforced concrete, permitted by the authorities under special license and designed by the architect Edouard Arman. It was a commercial triumph of space economy and its design captured the imagination of the architectural world. It was, perhaps, exceeded by the show-stopping house he went on to build for himself in 1904, at Bourg-la-Reine. Here, cantilevers supported overhangs, turrets and a roof garden, acting as a highly personal statement of his achievements and ambition.

Hennebique was nothing if not an assiduous promoter of his system. Collins states that he believed the true discoverer of something new is “he who says it so load, and so long, and so clearly, that he compels mindkind to hear him.” He devised a slogan (“Plus d’Incendies Destrueux”), a trade name (“Beton arme”) – and launched a magazine of the same name in 1898 – and held a series of periodic congresses to bind the various agents and contractors to his organisation. He cultivated an esprit de corps by hosting staff banquets to celebrate the award of every thousandth contract. And as the business grew so the interval between such banquets diminished. In the first six years contracts doubled annually, with 827 awarded in 1898 [McBeth, p20]. The following figures, derived from different sources, may not have been compiled on a consistent basis, but they indicate the pace and scale of growth:

By 1899 - 3061 projects had been won - plus 8078 proposed but not awarded [Bussell]

By 1902 - 1,500 contracts undertaken in the year

By 1909 - 20,000 structures had been completed

By 1911 - 1,073 had been built in the UK alone

By 1917 - 17,62 building contracts had been completed and similar for civil engineering

[Collins], around 35,000 in all [McBeth]

By the time of the First World War Hennebique’s organisation was huge and was outgrowing its original modus operandi as national businesses matured. Even by 1909 there were 62 offices worldwide: 43 in Europe, 12 in the USA, 4 in Asia and 3 in Africa. One of the first of these overseas offices was that of Louis Gustave Mouchel in the UK.

Louis Gustave Mouchel (1852-1908)

Mouchel was born on 11 January 1852, in Cherbourg, and originally was known as Gustave-Louis. On leaving naval college he joined the Department of Highways as resident engineer, and from 1872 followed an engineering course at the Government School of Mines.

In 1875 he left France and moved to south Wales where he settled in Briton Ferry. There he developed a career in the local coal and iron industries, importing ore from Brittany and exporting Welsh coal in the return trade. He founded the Cardiff Washed Coal & Fuel Co. and introduced coke making to the area, and became a director other local enterprises. With his involvement in cross-channel shipping he was appointed in 1879 as vice-consul responsible for the ports of south Wales, organising French ship movements in Swansea and neighbouring harbours.

Possibly it was this shipping activity that first brought him in to contact with Hennebique who had recently established an agency in the port of Nantes. Certainly Mouchel engaged him to carry out designs for the extension of his works and was apparently sufficiently impressed that he introduced the representatives of the Swansea firm Weaver & Co to Hennebique in 1897. He travelled to France with one of Weaver’s directors, and was instrumental in persuading them of the merits of reinforced concrete as the preferred material for their proposed provender mill. The building was erected in 1897-98 and during this time Mouchel accepted an appointment as Hennebique’s general agent in the UK. This business, operated under an exclusive license, was formalised as ‘Mr L.G. Mouchel, General Agent, Hennebique’s Patent Construction in Ferro-Concrete’. The choice of ‘ferro-concrete’ to describe the patented system of reinforced concrete was of Mouchel’s own devising. Henceforth the extension of this system was be “the chief object of his professional life” [Life and work of Louis Gustave Mouchel, p.212].

Mouchel undertook training with Hennebique and set up his own organisation in Great Britain along similar lines. He shared Hennebique’s expansionist, entrepreneurial approach: patenting designs, letting construction work to licensed contractors, vigorously promoting the Hennebique system through invitations to observe tests, giving lectures and publishing promotional literature. In this he was very successful and his obituary claimed that “by sheer pertinacity and the manner in which he inspired confidence, [he] obtained the ear of professional men of influence who adopted the system of construction he represented.” [C&CE v.3].

His first contract as General Agent was secured in 1897 and was to design a river-retaining wall, founded on concrete piles, for the London & South Western Railway at Southampton. The railway companies were among his earliest clients – most notably for their dock operations – along with the Co-operative Wholesale Society, grain merchants and assorted industrial firms.

Under the terms of his contract, Mouchel paid two thirds of his consultancy fees to Hennebique, whose staff carried out the designs in France – at least to start with – leaving one third for securing and overseeing the work and translating documents into English. “In organisation, in his arrangement of contracts, and in what might be termed his ‘intelligence’ department, he probably stood unrivalled.” [obit], and as the business expanded, engineers and draftsmen from Hennebique’s head office joined him. Among these were C. Roch and, in 1899, A.T.J. Gueritte – his eventual successor.

Gueritte was born in Blois on 7 March 1875 and on leaving the army he joined the group of engineers that Hennebique had gathered about him to advance the commercial practice of reinforced concrete construction. He was soon entrusted with checking the structural design of all Hennebique projects undertaken outside France and consequently gained a breadth of experience in the new methods that it would have been difficult to match at such an early date. Gueritte came to Great Britain to help in the negotiation of several contracts in northern England and in 1900 took up residence in Newcastle upon Tyne to supervise the resulting works.

Also in 1900 Mouchel moved the head office of his thriving agency to London, where he occupied somewhat spartan premises newly built for one of his clients, the Great Western Railway. A year later he transferred to a permanent business address, 38 Victoria St., Westminster, and took a flat in nearby Caxton Street where lived alone in Iddesleigh Mansions. A bachelor he had no hobbies, but, according to The Builder, “lived entirely for his work”.

Mouchel renegotiated his contract with Hennebique and thenceforth retained two-thirds of his fees. He also began to patent his own reinforced concrete designs that extended Hennebique’s system, particularly in areas of his own engineering expertise. In 1900 for instance, he patented the grouping and protecting of piles by means of cylinders for heavy jetty work – ‘hollow diaphragm piles’ – a system that was first employed at Dagenham jetty. His company’s later publication, Hennebique Ferro-Concrete: theory and practice, described him as “the first engineer to make a special study of this form of construction as applied to marine works.” Likewise, Gueritte later pointed out:

“It is worthy of notice that from the very first L. G. Mouchel had introduced in this country the latest development in reinforced concrete, viz. piles, which were to become so widely used in this country but which at that time had never yet been used on a big scale even in France.” Gueritte (1926) p.89

In 1903 Mouchel awarded Gueritte responsibility for the North and Scotland, where among osther successes, he secured the contract to design the landmark, eight-storey, Lion Chambers in Hope St., Glasgow.

Much of the actual construction work came to be taken by new specialist contractors in which Mouchel had a stake, companies that included the Colonial Ferro-Concrete Syndicate Ltd; Liverpool Henebique Ferro-concrete Contracting Co., Ltd; and – most prominently of all – the Yorkshire Ferro-Concrete Contracting Co., Ltd. But often work was fulfilled by established contractors, such as John Aird and W. Cubitt & Co, and so use of the patented systems was legally protected, with breaches vigorously challenged in the courts [C&CE v3].

He successfully sued Cubitt & Co for a breach of licence terms in 1906, for instance, and took his rival Coignet to court in a long-running case for patent infringement. The latter initially went in Mouchel’s favour, only for the Lord Chief Justice to pronounce that reinforced concrete was a discovery, rather than an invention.

As the market for reinforced concrete was opening up he was diagnosed with stomach cancer and in December 1907, knowing his remaining time was short, he transformed his business into a limited company with a capital of £50,000. L.G. Mouchel & Partners Ltd has remained in business for over 100 years, being taken over by Kier only this year. Gueritte and J.S.E. de Vesian were appointed as co-directors, while R.E. de Vesian and F. Geogheghan also held shares. Mouchel travelled to Paris for surgery before finally returning to his hometown of Cherbourg where he died on 27 May 1908 aged 56.

His relatively brief career in concrete had seen a spectacular increase in the use of ferro-concrete. Between 1897-1899 only seven Hennebique-framed buildings were commissioned in Britain; in 1908 alone there were 40. By 1909 there were some 1,000 reinforced concrete works, most of them commercial or industrial, of which 70% usedthe Hennebique system through Mouchel’s agency. These included over 130 reinforsed concrete frame buildings constructed between 1895-1908, and similar number for parts of buildings. There were 89 bridges and a similar number of water and colliery works. In each case Mouchel or one of his subordinates was responsible for designing the reinforcement, acting under the instructions of either client or architect, and supervising the reinforced concrete work.

1897 Weaver & Co’s provendgr mill, Swansea (first reinforced concrete frame building in the UK)

1897 Retaining bank, Routhampton (Mouchel’s first contract as General Agent)

1899 Woolston Jetty, Southampton ; 136 x 100 ft (first reinforced concrete jetty built in the UK)

1900 Dagenham jetty (first use of patented cylinder-protested piles)

1900 CWS warehouse, Newcastle-On-Tyne

1900 Mayrick Park water tower, Bournemouth (first reinforced concrete water tower in the UK)

1900/4 Cold store, Southampton (largest in the world at the time, founded on 1,000 piles)

1901 CWS grain silos, Dunston-on-Tyne; 14ft x 45ft (first reinforced concrete grain silo in the UK)

1904 Coal bunker, Park Royal, London (first reinforced coal bunker in UK)

1904 Newton-le-Willows water tower, Lancashire; capacity: 300,000 gallons (largest in the world

at time of construction)

1904/5 Ouseburn river conduit, Northumberland; 33 ft wide, half a mile long

1905 Waterford Viaduct, Waterford Quay, Ireland; 720 ft long, on piles 62 ft long

1906/7 Circular grain silos, Dunston-on-Tyne; 46ft x 72ft deep (first circular silos in the UK)

1907/10 General Post Office, London

1908 Royal Liver Building, Liverpool (first British ‘skyscraper’)

1908 Stakeford highway bridge, Northumberland

1908 Brooklands motor racing track, Weybridge

Looking back over these years, Gueritte evaluated Mouchel’s unique contribution in a paper for Concrete & Constructional Engineering, ‘The first decade of reinforced concrete in the United Kingdom (1897-1906)’.

Mouchel’s expansionist drive was continued, with the magazine Ferro-Concrete launched under the editorship of W. Noble Twelvetrees to promote the company’s successes and cultivate the market for reinforced concrete.

The Edwardian Years

Rival systems in the early twentieth century

With such a grip on the market there was an understandable reaction against Mouchel and the Hennebique system by fellow engineers, and other proprietary systems were soon patented in turn. By 1905 there were over 50 such systems in the UK and more than 70 by 1910 [Kempton Dyson]. Of these some of the better known included:

Cottancin Operating in Britain 1902-06 [Edgell]; office opened in 1904 [Collins]

Monier Marketed since 1902 by the Armoured Concrete Construction Co

[Chrimes] with a British office opened in 1904 [Collins]

Coignet 1904, Mr G.C. Workman appointed General Agent for the UK by

Coignet, who then built a group pf tobacco warehouses in Bristol and

in 1908 became a limited company, Edmond Coignet, Ltd

Truscon Julius Kahn obtained British patent in 1903, opening in London, 1906

Indented Bar Employed Burnard Geen in 1907 [ET]

Considere Messrs Considere Constructions, Ltd, opened in 1908 [ET] and built

the Angel Road Viaduct in Tottenham that year [Chrimes]

As well as the British specialists BRC (est. 1905) and the long-established E.P.

Wells, who worked with Stuart’s Granolithic Co.

The liberalisation of reinforced concrete in the UK before the First World War

In these early years of the twentieth century, Mouchel – and the increasing number of specialists with an interest in reinforced concrete construction – had many obstacles to face, including professional ambivalence or hostility, typified by the adverse attitude displayed by Henry Statham, editor of The Builder. Not least was the proscription of reinforced concrete, or at least the lack of provision for its use, under the Greater London Building Regulations that had been introduced by the London Building Act 1894. In consequence much of the early adoption was in provincial cities far from London – Glasgow, Hull, Liverpool, Manchester and Newcastle – by self-governing clients such as the co-operative societies, or by the autonomous water boards, dock and harbour authorities, and railway companies, for industrial or civil engineering projects. One client that was free from local authority control was the Government itself and Sir Henry Tanner, appointed Chief Architect to the Office of Works in 1898, was a well-placed champion for reinforced concrete. He commented on the situation:

“There has not been hitherto in this country any authoritative pronouncement on the necessary rules to be observed in such construction. In many ways this has prevented employment of reinforced concrete, such employment being practically prohibited for complete buildings under the ordinary building rules and regulations; and it is only those bodies who are free from these restriction, such as railway and dock companies, who have been able to avail themselves of so economical and space-saving a method of construction, and on these points I speak from experience.”

He specified it for the new GPO offices in King Edward Street and similar Post Office buildings elsewhere in London. Built to the Hennebique system, the new King Edward Street building was the first of its type in the capital, and for many years the largest.

The path to broader acceptance was not a straight one, but the principal staging posts along the way can be summarised as follows:

1904 Archibald Constable of London published the first British textbook on the subject, C.F. Marsh’s Reinforced Concrete.

1906 Edwin Sachs launched Concrete and Constructional Engineering to promote

reinforced concrete construction and make available overseas experience. The monthly journal was to be “a reliable digest of the world’s latest information”, with the “latest scientific data from pens of undoubted authority”.

1907 The Royal Institute of British Architects published the first report of its Committee on

Reinforced Concrete, chaired by Sir Henry Tanner, which proposed “rules for the guidance of architects for the use of reinforced concrete”. Marsh was also member of the committee, as were representatives of a wide range of interested parties.

1908 The Concrete Institute was founded by Sachs as a technical body to promote the free

development of reinforced concrete, and in part to counter the purely commercial interests of specialist reinforcement patentees. Tanner served as Vice President, and from 1910, its second President.

1909 The London Building Act was amended to permit new regulations on reinforced

concrete in line with recommendations made by the RIBA and members of the Concrete Institute.

1910 The Institution of Civil Engineers issued a preliminary report on reinforced concrete.

1911 The RIBA issued a further report, and the Greater London Council issued draft Regulations for comment.

1913 The Greater London Building Regulations were amended and agreed.

1915 The Regulations were finally issued in July.

Early Reinforced Concrete Bridges in Britain

The finest Hennebique bridge was built in 1899, at Chatellerault, over the River Vienne in western France. In Britain concrete bridge building was rather more modest and, given the climate described above, tentative. The first, an 18ft span at Chewton Glen in Hampshire, was designed in 1900 and opened in 1902, followed by several municipal bridges of 40-50ft span in the north of England, such as the 40ft beam-and-slab bridge at Sutton Drain, Hull, built in 1903. Such bridges could not, admittedly, be “regarded as imposing”, but were described by the company’s spokesman as “practical and satisfactory” [Gueritte]. They were, in fairness, built without design standards and local specifications were devised without any national guidelines. All the basic structures were adapted from traditional forms, or developed abroad – firstly by Hennebique and later by his emerging rivals.

Mike Chrimes, formerly head librarian of the ICE, has calculated the total number of reinforced concrete bridges built before the war and, with 80% of the output, the dominance of Mouchel is striking:

Reinforced Concrete Bridges built in the UK to 1914

(after Chrimes)

They represent a range of structural types, described at the time by Twelvetrees and categorised with dates by Chrimes:

Bridge type Earliest example

Beam and slab (parallel longitudinal beams, flat or haunched) 1902

Beam and slab (ditto with soffits curved to resemble arches) 1904

Variable depth trusses 1903-04

Slab vaults (with infill retained by spandrel walls 1904-05

Open spandrel arch 1904-05

Solid spandrel arch 1901-02

Portal frames 1910

Vierendeel girders 1904

Yet the pace of progress was deemed slow in comparison with that of other structures:

“It seems to be only in bridge construction that progress was slow, not as regards numbers, as even in those early days the number of bridges carried out was great, but as regards span … it was only in 1907 that spans approached 100 ft, and no bridge of span exceeding 150 ft. had been constructed in this country until 1922.” [Gueritte (1926) p.92]

If we review the largest spans of Mouchel bridges built prior to Bow Bridge, we see that progress was not linear over this first phase.

Mouchel bridges with spans of 60 ft or more, prior to Bow Bridge – by length of span (ft)

Listing them by date we see that initial progress plateaued after 1907 at around 60-100 ft and did not notably increase until 1914:

The largest spans of Mouchel bridges prior to Bow Bridge – range by year

In the months that Bow Bridge was designed and built at Wateringbury, Mouchel’s recently launched house magazine, Ferro-Concrete, chose to feature a number of recent bridges and the selection gives an indication of the state of the art and what was deemed worthy of notice:

Recent Bridges featured in ‘Ferro-Concrete’

Of these the Esk Bridge at Floriston, near Longtown in Cumberland, was perhaps the most distinguished, and certainly with the longest span. It was of the open spandrel design, the signature Hennebique design. Most of the others were short, single span structures, and perhaps modest ambassadors for their designer.

For actual contemporaries of Bow Bridge, the published job list indicates 18 contracts between the announcement of the project in 1914 and the additional design work in early 1915:

Bridges on the Mouchel Job List, 1914/15

Wateringbury Bow Bridge (296ft long by 18ft wide)

Heriot (Scotland) Heriot Water Bridge (34ft span by 20ft wide)

Longtown Esk Bridge (three spans, the central one 175ft)

Stafford Two bridges over the River Blythe

London Raneleigh Road Bridge (piling)

London Additions to coaling viaduct, Wimbledon

Carshalton (Surrey) Hackbridge highway bridge over the River Wandle

Swansea Bridge over Tennent Canal (foundations)

Rotherham Bridge at Park Gate (additional work)

Cardiff Virgil Street Bridge (abutments)

Velindre (S. Wales) Highway bridge

Grimesthorpe Bride (44ft span, 10ft wide)

Sunderland Faulkner’s Bridge

Nottingham Bridge over Nottingham Canal

Langford (Essex) Highway bridge

Woking Broadmead Bridge over R. Wey (50ft span, 22ft wide)

1915

H. Wycombe Besborough Avenue Bride

Wateringbury Bow Bridge (additions)

[Anon, 1919]

They are distributed across the country – Buckinghamshire, Cumberland, Durham, Essex, Kent, London, Nottinghamshire, Staffordshire, Surrey, Yorkshire, Scotland and Wales – with clusters in Yorkshire and the north Midlands, south Wales and Home Counties.

From these examples it will be seen that Kent does not figure as a favoured location. There appears to have been only one previous reinforced concrete bridge project in the county, though possibly a significant precedent for the bridge at Wateringbury. In 1913 the Dover Borough Council commissioned a street viaduct and three bowstring girder bridges. The latter three are of little consequence here, but we do know that Bow Bridge is a trestle bridge – which implies multiple short spans and numerous supports (piles rising into columns) – and though there is no river involved in the Dover viaduct, it does look as though there may be structural similarities between the two bridges. Indeed there are possible parallels with two other Mouchel bridges of the period: the 365ft long trestle construction over the River Slaney at Ferrycarrig, near Wexford (1914), and the design of the admittedly much shorter Velindre Bridge at Aberavon. These bridges were contemporaneous with that at Wateringbury, to which our attention finally turns.

Bow Bridge, Wateringbury

A bridge across the Medway at Wateringbury had existed since the eighteenth century, but had long been considered in need of replacing. A previous scheme to span both the river and the recently laid railway at this crossing point had been abandoned in 1868, the County asserting that it was a matter for the South East Railway and Medway Co., the latter of which had offered a contribution of £100.

In 1914 plans for a new bridge to replace the existing, but by now dilapidated structure were advanced. Funds amounting to £4,000 were raised, of which £1,000 was paid by the local authority and a further £1,000 by the Rochester Bridges Trust (est. 1383), and a ferro-concrete bridge was commissioned by Maidstone RDC. It was designed by Rowland H. Halls of Lewes and conformed to the Hennebique system. L.G. Mouchel & Partners detailed the reinforcement, with additions in early 1915, and the construction was undertaken by licenced contractor the Yorkshire Hennebique Co. of Leeds.

The design was of the trestle type, with multiple spans amounting to 291 ft in length and 18 ft in width. Ten pairs of piles, 16 in square, were moulded on the riverbanks and after 8 weeks slung into position. There they were inserted by pile driver, and a 30-cwt ‘monkey’, 26 ft into the dark clay below the riverbed, yet it was said that no pile was destroyed or damaged during the project. When completed the bridge was described as “more convenient and more commodious” and – tested by two steamrollers proceeding abreast – was capable of carrying a moving load of 30 tons.

The new Bow Bridge was officially opened at a ceremony on 22 July 1915 by Mr George Machin JP, Senior Bridge Warden and a member of Kent County Council. Mr De Vesian, one of the co-directors of L.G. Mouchel & Partners, commented that though ferro-concrete was relatively new in Great Britain, 1,500 bridges had been built with it worldwide. Speeches ended with God Save the King and – surprisingly – the Russian national anthem!

Completed during the opening stages of the First World War, at a time when new national regulations were being introduced, Bow Bridge marks the closing of the initial phase of reinforced concrete development in the United Kingdom.

Edwin A.R. Trout

August 2015

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