CONCRETE CONSTRUCTION. A His torical Account.— As in the history of other arts we find early disclogures of the principles of action of various later constructions. Before construction in reinforced concrete strengthen ing of brick masonry arches by iron ties to prevent opening of cracks in tension was well known. In 1836 Brinell experimented with brick beams so strengthened and found the two acted together. In 1871 Sir Shafto Adair built a concrete arch of 50-foot span with a rise of five feet three inches, containing an embedded iron skeleton frame. The treatise on concrete by Francois Coignet, of France, published in 1861, describes the embedment of an iron mesh in concrete to increase its resistance to tension, and describes the making of pipes. It is said that he built a roof slab 12 inches thick and 20-foot span, in 1852 at Saint Denis. (Concrete, London, June 1910).
Coignet's patent of 1869 consists in the in troduction in the body of the structure of double headed nails, double T pieces, clamps, hoops — for the purpose of strengthening some and giving it greater cohesive strength. The iron was to be interlaced so that by the com bination of the metallic skeleton and of ag glomerated artificial stone paste the thickness of the walls or size of articles might be con siderably reduced and yet great strength be attained. Troughs were to be strengthened at the corners by iron clamps.
The book by Thaddeus Hyatt published in 1877 discloses improvements in fireproof con struction, describes experiments in reinforced concrete beams and analyzes the principles of action of these. He protects the I beams from fire by a covering of concrete, and between these he builds slabs reinforced for tension by plates of iron placed vertically in the bottom of the slab and connected by small round rods. He understands the mechanics of the reinforced concrete beam; and the part played by the metal in moment and horizontal shear. He also investigated experimentally the elements of strength of the two materials, strength, modulus of elasticity, expansion and contrac tion, fireproof qualities. Hyatt was a practical
contractor, a successful inventor, and his book is the first definite treatment of reinforced con crete.
J. F. Monier, a gardener, was one of the fathers of reinforced concrete. His first work was in making flower pots. His first patent was dated 1867 and the drawings disclose many of the elements to-day employed. In 1884 the rights of the Monier patents for Ger many were purchased by Wayss SE Company, which, after experimental and theoretical study, published a brochure entitled
In the United States, Ransome in 1884-95 was building various structures with hoop iron and wire rope. A house of reinforced con crete with beams and slabs was built in the United States by Ward in 1875. Thatcher ap plied the Melan system to bridges. J. Kahn and A. L. Johnson designed and built up a wide range of structures. After 1902 the uni versity laboratories were fruitful in research. For further reference consult P. Christophe, (Le Beton Arnie) (ed. by Beranger, Paris).