HISTORY OF REINFORCED CONCRETE The history of reinforced concrete seems to be a very uncertain quantity. Authors vary as to the date at which it made its first appear ance; also, as to the form in which it first came into public notice. In fact, very little authentic history is available concerning its truly early stages. Its history since the nineties, however, is well recorded and is being recorded in endur ing form by the increasing number of uses to which it is being subjected each year.
Some of the earlier records furnish interest ing forecasts which are to-day becoming real and important factors in construction work. Louden, in his "Encyclopedia of Cottage and Villa Architecture," wrote: "Floors and roofs might be made flat by means of a lattice-work of iron tie-rods, thickly embedded in cement or concrete and cased with flat tiles." Here we see another forecast of reinforced concrete as practiced to-day.
A Frenchman, M. Lambot, patented in France in 1855 a system of reinforcement which he called a substitute for wood, and which sisted of a network or parallel set of wires, bars, or rods, embedded in or cemented together with hydraulic or other cementing matter, so as to form beams or planks of any desired size.
This was the same year that M. Francois Coignet, also a Frenchman, patented a system for making concrete, or beton, from hydraulic lime. In 1861 M. Coignet published a pamphlet advocating metal reinforcement, and described various ways of applying it for strengthening concrete floors. But although his system ap pears to have received some attention in France, it was not until 1879 that any work was carried on by him there.
The much earlier systems of Lecomte, Thu sane, and others, of using rods and bars em bedded in concrete, probably had something to do at least with suggesting these inventions. About 1860, Mr. Brannon, an architect and engi neer, anticipated the use of wirework and iron in other forms as reinforcement, for he describes his invention as: "A method of forming roofs, floors, ceilings, doors, walls, and other parts of buildings, or other structures, of cement or concreted materials in combination with metallic, fibrous, or laminated substances, with a view to render them more durable, fireproof, and healthy; and it consists in employing for the said purposes a sustain ing metallic framework or skeleton, firmly fixed and bolted or bound together, upon which is stretched wire work, so as to partially enclose or be completely em bedded in the said concreted materials which compose the body of a structure, or any part thereof, thereby perfectly bonding the same into a solid and coherent mass."
The system was, however, too costly and in tricate to come into general use.
When, in the late sixties, M. Monier, a French gardener, began making flower-pots, boxes, and small water-tanks out of concrete, and embedded wire in the material to increase its strength and decrease its weight and bulk, he little thought that forty years later the prin ciple which he used and upon which he was granted a patent, would be used throughout the entire world in the erection of millions upon millions of dollars worth of construction work.
One of the first uses of reinforced concrete in building construction was in the house erected by W. E. Ward in 1872, at Port Chester, N. Y. As previously mentioned, however, some twenty years earlier than this, in France, the first com binations of iron imbedded in concrete were made in a small way. But it was not until the very end of the last century, since 1895, that re inforced concrete came to be employed com mercially in the construction of buildings. Pre viously to this the plain type of construction had attained a wide use in foundations, and at this time its development was beginning for such structures as dams, sewers, and subways.
Two principal reasons may be offered for this comparatively slow growth followed by such marvelous activity. In the first place, Portland cement manufacturers, beginning in Europe about the middle of the 19th century and in the United States about 1880, finally produced a grade of cement which, with the inspection nec essary for all structural materials, could be de pended upon to give uniform and thoroughly reliable results; furthermore, along with the perfection of the process of manufacture, the price gradually fell from the high cost per barrel in 1880 for imported cement, to a figure for do mestic Portland cement of equally good, if not better, quality, at which concrete in plain form could compete with rough stone masonry, and, with steel embedded, could compete with other building materials.