The Hastings Standard. TUESDAY, DEC. 10, 1907. FERRO-CONCRETE.

Hastings Standard, Volume XI, Issue 5681, 10 December 1907, Page 2

The Hastings Standard. TUESDAY, DEC. 10, 1907. FERRO-CONCRETE.

By the courtesy of Mr J. McAven, the engineer-in-charge of the ferroconcrete contracts i ! Hastings and Napier, we are enabled to publish the remarkable results of a test made by him last week to ascertain the actual load which would have to be applied to bring about the collapse of a ferro-concrete slab. Our readers on referring to the report of the test will probably be amazjd at the strength of the combined materials, and the following information legarding the use to which ferroconcrete can be applied will no doubt be read with interest. At the International Congress of Architects, held last year, and bv the professional soci- ties generally, much attention has been given to the matter in its technical aspects; books on the subject are numerous, and one periodical is entirely devoted to it. Regulations have been drawn up in Switzerland (1906) respeciing this form of construction —oi' which, as aforesaid by one writer, "the extensive use in all classes of building construction in the near future is a certainty.'] What, then, are the principles of the new method? "Briefly speaking," says Mr Alfred T. West, an authority on the subject, "it is the employment of the two materials in such a relation that the tenacity of the one and the solidity of the other are employed to their mutual advantage. To quote a French treatise : " Les ouvragesen betonde ciment armesont formes d'un squelette en pieces de fer ou d'acier noyees dans un beton de ciment. . . . le fer et le ciment se partagent le travail de resistance.'' That is to say, a steel skeleton is encased in concrete and each takes its share of stress. This happy combination may be compared to a marriage of two dissimilar but cornplementaiy natures, like our old friends Jack Sprat and his wife, of nursery rhyme celtbrity. Concrete is strong to resist compression, but weak undjr tension ; the steel reinforcement is put into "lake up tensile stress," being several hundred times as strong as concrete in this respect. At the same time, the concrete enveloping the steel preserves it from rusting and from the effects of fire, stiffens it laterally, and generally gives solidity and homogeneity to the structure. Aftei severe tests by fire and by explosives, ferro-concrete is reputed to be almost indestructible. Several bu ldings ani bridges near San Francisco received the full force of the earthquake last year and suffered no damage. The destructive toredo, or sea-worm, has no terrors for it—nor can it rot, as does timber, and the concrete increases its strength with ag?." This method of construction shows a remarkable adaptability to all pu poses from foundation piles to chimney shafts. Piles of ferro-concrete can be driven into the ground as well as, or better than, timber ones. For floors it is, of course, eminently adapted. Bridges have b.'en constructed in great numbers ; a graceful bridge over the Isar at Munich showed its strength in the heavy floods of 1899, when the river flowed right over it without damage, while an adjacent masonry bridge was completely swept away. As another instance of stability under trying conditions, a curious case was reported in 1906 from Tunis. Owing to a failure of the ground, a lofty ferro-concrete grain store tilted over to the extent of 25 degrees (the leaning tevver of Pisa inclines at only three or four degrees) and was subsequently restored to vertically without distortion. Bui:^-

ings can be restored with great rapidity entirely of this material; for factories, its freedom from vibration adapts it for carrying running machinery. Wharves, wareh.unes, coal silos, factory chimneys, aquaducts and large sewers are all made of ferroconcrete with advantage. Retaining walls on this principle require but a fraction of the material formerly necessary. Lars? circular reservors (of which the walls need but be a £. w inches thick) are much in vogu \ especially on the Continent. Tlu' Brooldands motor-racing track is

formed of ferro-cincrete. Examples might be multiplied, but enough has been said to indicate the multifarious uses to which this method ot construction may be applied.