Repository: UIHistories Project: Dedication - Ceramic Engineering - Journal Article [PAGE 7]

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JOURNAL

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INDUSTRIAL AND

ENGINEERING

CHEMISTRY

7

of these studies. A second volume was published in 1871 which gave the results of other studies. Paul Alexandre and R Feret. French scientists, made important contributions to our knowledge of the strength and other properties of hydraulic mortars and concrete during the years 1888-1893. The first uses of concrete considered taking advantage only of its compressive strength, that is, its ability to bear loads placed directly upon it. But like building stones, for instance, concrete is strong in compression but weak in tension and little progress was made in developing the possibilities of concrete as • structural material until it was combined with metal, such as Iron or steel rods or other fabricated reinforcement, to compensate for its deficiency in tension. To-day the value of concrete as a structural material is due largely to the development of reinforced construction. Such concrete has been referred to in various ways, the terms "ferro concrete" or "armored concrete" were once general and even" to-day are in popular use abroad. The combination of steel and concrete has resulted in a building material different in properties from any other and for which the usual formulas of design, such as those involving stress distribution, do not apply. Therefore, it has been necessary for a time to assist in developing the men of science who have aided in solving the problems that were and are still sometimes encountered in making the best use of this most modern building material.

REINFORCED CONCRETE

characteristics into a single structural unit has made it essential that new principles be developed which could be applied to the analysis of members of this character. For the first time we are able to construct building in such a way that they are of monolithic nature. This has made it essential that methods of analysis be developed which would apply to continuous beams and slabs, and combinations of beams, columns, walls, etc., in a manner that has not been necessary with other materials. The experiments carried out by Hyatt attracted considerable attention and showed the true principles of the action of reinforced concrete beams under load. However, developments in the uses of reinforced concrete were limited until about the beginning of the present century. Prior to this time a few isolated experiments had been conducted in Germany, Switzerland and France in promoting the use of certain so-called "systems" of reinforced concrete construction. These consisted of patented arrangements of reinforcing steel, many of which were of poor design and wasteful of materials. Practically no research work was done in the United States on the subject of reinforced concrete prior to the year 1000. Since that date the combined efforts of many investigators in the United States, Germany and France have furnished us with a large stock of information concerning the action of reinforced concrete. The year 1903 saw the inauguration of several independent researches in the United States on the properties of reinforced concrete beams. Professor A. N. Talbot, of the University of Illinois, made his first experiments on reinforced concrete beams during this year. Experiments along similar lines were carried out during the same year by Professor W. K. Hatt, of Purdue University, Professor Edgar Marburg, of the University of Pennsylvania, and by Professor M. A. Howe, of the Rose Polytechnic Institute. Since 1903 numerous other experiments have been carried out by the above-mentioned institutions and by the University of Wisconsin, the United States Geological Survey, The United States Bureau of Standards and others. Prior to these extensive experimental studies, reinforced concrete was designed by purely empirical methods. It was impossible for reinforced concrete to reach its proper development until such experimental studies as those mentioned above had shown that: (1) There is a definite and positive adhesion or bond developed between concrete and steel which can be depended upon to transmit the stresses from one material to the other. (2) Iron or steel embedded in well-made concrete is perfectly protected against corrosion and deterioration of all kinds. (3) The coefficients of linear expansion of concrete and steel due to changes in temperature are practically the same. (4) Rational analyses may be applied in determining the stresses developed in reinforced concrete members due to applied loads. It seems probable that no one institution has contributed more to the literature of this subject than the Engineering Experiment Station of the University of Illinois. This experimental work was begun by Professor A. N. Talbot in the year 1903, and has been continued up to the present time. Large numbers of tests have been carried out each year on reinforced concrete beams, columns, slabs, bridge girders, culvert pipes, footings, rigid frames, and on completed structures, A great deal of the development of reinforced concrete construction has come about as a direct result of the scientific studies of this subject which have been carried oat by Professor Talbot and his assistants. The importance of Professor Talbot's contributions to this subject may be seen from the fact that the nomenclature used by him ID some of the earliest publications of the Illinois Engineering Experiment Station has become the universal language in the literature of reinforced concrete. To the Engineering Experiment Station of the University of Illinois the world is also indebted for the comprehensive tests tabulated In Bulletin 71 of the Engineering Experiment

The early history of reinforced concrete is most interesting. It appears that the first use made of metal reinforcing in com* bination with concrete was by certain French artisans about 1855 to 1865, in making small boats and flower pots. These men conceived the plan of strengthening their concrete products fay embedding iron wires in the fresh concrete. Little did they dream at this period of the importance this principle would have. The first instance of any importance in which the principles of reinforced concrete construction were applied was in a dwelling at Port Chester, N. Y.. built in 1875 by W. E. Ward. This was the first example of reinforced concrete construction which in any way approached our present conceptions of this material. The further development of reinforced concrete construction was extremely slow, as fifteen years elapsed before we find another example of its use in any important structure in the United States. It is probable that reinforced concrete would still be one of the curiosities of building construction were it not for the fact that men of science have searched for and discovered the principles underlying the action of this material, and nave shown now structures of reinforced concrete may be designed in a rational way. The first scientific study of a combination of concrete and iron in the form of reinforced concrete was carried out about 1875 by the laboratory of David Kirkaldy, of London, at the request of Thaddeus Hyatt, Hyatt was a citizen of the United States at that time residing in London. In 1877 a book was published by Hyatt giving the results of these investigations. Although this book was printed for private circulation and has long been out of print, H has attained rank as a classic in the literature of reinforced concrete. Hyatt was probably the first to recognize the fundamental principle of reinforced concrete which involves the use of reinforcement to take the tensile stresses which would otherwise be thrown upon the concrete. At the same time he recognized the necessity of a permanent bond between the concrete and the reinforcing metal, and the importance of similar action of the two materials when subjected to changes in temperature. The tests described by Hyatt were carried oat for the purpose of securing information on these subjects. The use of concrete as a structural material has given rise to many problems which have commanded the attention of scientists. The combination of two materials of entirely different