Part 38

The viaduct from Long Key is 2 miles long and passed through water having a depth ranging from 13 to 20 feet. The floor of the Gulf is of coral. To construct a pier, about 30 piles would be driven in with their tops projecting up from the floor. A cofferdam would be sunk to include them and a seal of concrete 1 yard thick be placed. The water could now be pumped out and the form concreted. The reinforcement would, of course, be put in place before depositing this concrete. The pier would then be allowed 3 weeks to mature. The concrete was mixed with fresh water to avoid the effect of sea water on the steel. Corrugated bars were used in reinforcing the walls and the 184 arches. High water is 31 feet below the top of this structure, so that the track is well protected from the waves.

It may surprise some, but concrete has actually been used as the chief material in the construction of boats. A reinforced concrete boat was built thirteen years ago for use on the River Tiber in Italy. Not only the hull but posts and roof of the structure above deck were of 334 concrete. This house boat was 67 by 21 feet. Another Italian boat is the Liguria, a barge in actual service. It is 57 by 18 feet and is rated at 150 tons. The Gretchen is an American example of the stone boat. She has sailed over long distances on the Atlantic and was reputed as comparatively a rapid sailer in a heavy sea. Her reinforcement was a multitude of small rods. This boat drew 14 feet of water and was 65 feet long and had a beam measurement of 16 feet.

Concrete is an obvious material for coal pockets, especially because of its fireproof character. A further advantage is the avoidance of a large maintenance charge. At Charlestown (Boston), the Lehigh & Wilkes-Barre Coal Company had been expending about $1,000 yearly on repairs upon a coal pocket. This has now been replaced by a concrete structure having a capacity of 10,000 tons. It has a depth of 24 feet, and has a length of 182 feet and a width of 92 feet. It is founded upon 750 Simplex concrete piles. If wooden piling had been used, the amount of excavation thus necessitated would have been very considerable because it would have been necessary to cut them off 10 feet below the surface in conformity with the building laws. Moreover, about 2,000 wooden piles would have been required because of the limit of ten tons’ bearing capacity per pile. With the concrete piles, however, the footings for the columns were constructed with but little excavation. The columns, side walls, girders, beams, floors--pretty much everything except the roof--were of reinforced concrete. When a full load of coal is filled in on the floor, the weight per square yard is 18 tons.

A similar application is to the construction of grain elevators. Reinforced concrete has been used at Baltimore in two important buildings of this kind and also in the case of a third at Buffalo. The question of fire is here very important. The grain elevator of the Pennsylvania Railroad at Baltimore is the largest of the three and is 335 constructed to hold 1,000,000 bushels. There are 53 cylindrical bins having a common height of 79 feet. There are four rows of eight each. The remaining twenty-one bins occupy spaces in between, three rows seven in a row. The set of 32 have the larger size and measure 24.2 feet in internal diameter. The walls are 8 inches thick and have both vertical and circumferential reinforcement. The vertical reinforcement is round bars of 1⅜-inch diameter. The circumferential reinforcement consists of interlaced flat bars. By a patented device the bins were cast in sections. This mold would be attached to the heavier vertical reinforcement and jacked up as needed.

It is unnecessary to emphasize the fact that concrete while economical is not cheap. So that when large masses are used, it is advisable to reduce the expense by using what may be called “pudding stones.” At McCalls Ferry a large dam and adjoining power house span the Susquehanna River. This is a tremendous application of concrete. However, pudding stones were very properly employed in the construction of the great dam. Here steel was employed not so much to reinforce but to supply frames for the molding surfaces. Great pelican cranes of steel were also employed to handle the concrete, etc. The face of the dam is a double curve and thus required a precise mold. Sections of the dam, 40 feet in length, would be constructed to alternate with open spaces of the same length. When it was desired to close such open spaces, a great steel apron would be let down on the upstream face. Concrete could then be laid in the open space.

In all the applications of reinforced concrete with which our attention has so far been occupied, the case has either been one of well-recognized practice or closely related to such practice--with the possible exception of concrete barges. There are two other lines of engineering application in which it is very desirable to employ 336 concrete, but where we are scarcely entitled to regard its use as anything more than experimental. Reference is made to telegraph poles and cross-ties. If a concrete pole really proves adapted to its service, then we may expect a great reduction in maintenance expense. It is estimated that renewals of wooden poles in the United States cost yearly $13,000,000. The prospect of getting a pole which will not need renewal for a long period is certainly attractive. But the actual service is severe. This is due not so much to the load which must be carried as to the horizontal movements under wind pressure. But by using proper reinforcement, it is thought by some, the pole may be made to withstand the horizontal thrusts. Some experiments have been made of a type of pole recommended by the American Concrete Pole Company, Richmond, Indiana. Four vertical rods bound together by wire constitute the reinforcement. Such a pole 7 x 7 inches at the top and 12 x 12 inches at the bottom was tested to destruction. This pole was 30 feet long and had its butt end sunk 5 feet into the ground. The vertical rods were ⅝ inch in diameter and were bound with No. 9 wire. A horizontal thrust or pull at the top of 840 pounds accomplished a deflection of 6 inches. When this was increased to 1,780 pounds, the deflection amounted to 17 inches. When 2,800 pounds pressure was employed, the deflection was 30 inches accompanied by a slight cracking. A deflection of a full yard together with cracking at the ground line resulted from a pressure of 3,640 pounds. When 7,200 pounds pressure was employed, the cracking became bad and the deflection amounted to 60 inches. A cedar pole of the same size was deflected 11 inches by a pull of 840 pounds. With 1,780 pounds, the deflection was nearly a yard (33 inches); and with 2,200 pounds the pole broke about 3 feet from the ground. The problem of the telegraph pole will probably be solved, if this has not already been done. 337

With regard to the cross-tie the case is more difficult. Plain concrete slabs or beams cannot be used after the manner of the wooden tie because of their want of elasticity. What is called “center binding” would be disastrous to plain concrete. The rocking action of the passing load is also a factor which enters. One method of dealing with center binding is to divide the tie into two parts, connecting them with steel rods. The Corell tie is an example of this. In the Percival tie, the under part of the concrete block is given a sharpened edge. Beneath the rail itself, the cross-section is a kind of oval. There is longitudinal reinforcement in the form of four rods, three arranged at the top and one near the bottom. Three rods are bound with wire. There is a cushion block of wood which absorbs and distributes the shocks from the bottom of the rail. Screw spikes and metallic sockets are employed. Some three or more years ago a hundred such ties were put in service in a Texas railway. In June, 1909, seven only were found to have received serious injury. It is thought that this damage was scarcely chargeable to the ties themselves as when in position they were between wooden ones whose deterioration might easily have been the cause of undue disturbance being thrown on the concrete ties.

We have considered to a slight extent the use of steel as the material of concrete forms. This line of application, however, promises to become a very large one. Two notable constructions are now under way in which the steel form plays a large part. These are the great Gatun Locks of the Panama Canal and the Catskill Aqueduct. The three double locks at Gatun will require about 2,000,000 cubic yards of concrete. Each pair of locks is on a separate level and has three longitudinal walls. One separates the lock chambers. This central wall is 60 feet in width. It is not solid as so much concrete would not be required as 338 the water level is approached. Consequently, there is a kind of V-section which traverses it longitudinally. This is filled in except for three galleries--one for drainage, one for the electric wires and one for the men. There is a longitudinal culvert arranged below the fill in the body of the concrete wall. In the side walls of the lock chambers are other longitudinal culverts. From the central supply culvert transverse distributing culverts run off beneath the floors of the adjacent lock chambers. These have vertical outlets into the lock chambers themselves. Similarly, but for purposes of emptying the locks, the longitudinal culverts arranged along the outside are connected by transverse culverts and vertical openings with the lock chambers. The members of the two systems of transverse culverts alternate with each other. The main supply culvert has a diameter of 22 feet part of the way and of 18 feet part of the way. Now these many culverts, various in form and size, are to be molded in the mass concrete by means of steel forms. As originally announced, there would be 12 forms of open hearth boiler steel for the main supply culvert. Each of these weighs 177,000 pounds. One hundred forms were to be required. The two main outlet culverts of similar dimensions to the main supply culvert were thought to require 21 forms, each 12 feet in length and having a weight of 300,000 pounds. The transverse culverts were to require 100 forms, each having a length of 10 feet and a weight of 217,000 pounds. There were thus to be 133 forms having an aggregate weight of 15,000 tons. It is possible that there may be some modifications of this plan in minor particulars. The side walls of the lock chambers are to be mainly vertical planes having a height of, say, 81 feet. To retain the fresh concrete in place, 12 face plates, constructed of sheet steel are to be used. These are 7½ inches in thickness, having face dimensions 78 x 36 feet. Steel towers running on suitable tracks control these face plates. It is estimated that 339 towers and plates will have an aggregate weight of 26,000 tons. So that, quite apart from any possible reinforcement application, steel to the total of about 41,000 tons is to be used for forms and immediate accessories. But this 41,000 tons is not all. The concrete is to be cast in great monoliths and to retain the ends of these while the concrete is fresh, steel girders 6 feet high are to be employed. If these locks were to be of stone then steel would have played a rather subordinate part.

The Blaw Collapsible Steel Centering Company are engaged at Panama, but they are also applying their systems of molding concrete to the great aqueduct which is to supply New York City with water from the Catskill Mountain region on the other side of the Hudson River. A steel centering is used to give form to the interior. Steel forms are also employed to shape the upper part of the external surface. At Baltimore, more than three miles of sewer construction was carried out in accordance with the system of the same company. The centering used for one portion where the height was 11 feet and the width 12¼ feet (inside) was employed in 50-foot lengths. In 2 hours, 6 men could remove such a 50-foot section together with its falsework and have it in readiness for a repetition of its service. A typical half-round Blaw center consists of one or more steel plates bent to conform to a cross-section of a semi-circle. Turnbuckles retain this shell in position. If we are going to employ this form in sewer construction, we first dig out our trench to such dimensions and form as to furnish the mold for the outside surface of the lower part of the concrete sewer. We then lay concrete in a longitudinal strip along the bottom, giving the upper surface the form of a shallow gutter. When this is sufficiently hardened, the semi-circular center may be slid along it to suitable position. The center has its concavity opening upwards. The concrete of the invert of the sewer is now placed. The same or a 340 duplicate center may now be used to mold the interior of the upper part of the sewer.

Portland cement has been in use for a long time. But reinforced concrete is so modern that in some important lines of engineering application the fundamental data underlying practice are not fully determined. In what may be regarded as the first decade (1870-1880) of the considerable manufacture of Portland cement in the United States, the total amount produced was only 42,000 barrels. Fifty years and more would be required for the production of enough cement to construct the Gatun Locks. Over a decade would be necessary to yield enough cement for the operations of the Hudson Companies. The price at this period was about $3.00 per barrel. In 1908 it was 85 cents. But the production in this year was more than 1,200 times that in 1880. The value per year of the present output is about $50,000,000.

CHEMISTRY AND THE INDUSTRIES. 341

BY BENJAMIN BALL FREUD, B. S.

[Assistant Professor of Analytical and Organic Chemistry, Armour Institute of Technology.]

Chemistry has always been a utilitarian science, a science whose direct applications to our every-day interests has been on every side recognized. Even in the days of alchemy, that fantastic forerunner of our present science, her devotees were concerned with the changing of the base metals into the noble ones, of lead into silver, and of copper into gold, and also with the search for the philosopher’s stone, that mysterious something which would give perpetual youth.

From these workers arose in the course of the years, the facts and the theories which were incorporated into the science of chemistry. But it is not entirely to the alchemists that chemistry owes its development. By far the greater number of facts, if not of theories, came down to us through the traditional knowledge of the chemical industries. Numerous animal and vegetable products, such as sugar, starch, the oils, gums and resins, had been familiar commodities as long back as history records. And the ancients were informed in such typically chemical industries as that of dyeing with vegetable dyes, pigment manufacture, varnish making, soap making, paper making and the fermentation industries. In fact the science of chemistry as we have it today owes much more to these unknown workers in the industries who transmitted their chemical facts from father to son, than it does to the creations of the imaginations of those picturesque, if not so truthful, alchemists.

It is entirely impossible to divorce the science of chemistry from 342 its industrial applications. The science owes much to the industries. The industries owe even more to the science. And if that relationship has been very close in the past, it is much closer now than it ever was; and it is getting closer all the while. The utilitarianism of our age makes it absolutely necessary that the two shall be so united that the utmost of good shall result from the union.

The application of science in general, and of chemistry in particular, to the industries has this one general result. It takes that industry out of the “rule of thumb” class, and places it firmly on a sound basis. It is no longer conducted in a haphazard manner, but according to intelligent design, based on the most accurate scientific information. Of course the fierceness of business competition has ordered this change, more than any other factor. The pure science of chemistry would have developed without industrial applications, because there are investigators who are seeking the truth regardless of any of its immediate applications. But in the industries, it is a matter of dollars and cents. The most efficient is the winner. And the most efficient is the one who utilizes in his business all the scientific information that can be brought to bear on the subject, and who is always looking for new facts that can be applied.

Chemistry, then, is applied to the industries in two distinct ways, the first in discovery, in finding a new substance which can be used, or a new process by which some useful or necessary substance can be made; the second in improvement, in making a certain product better, or cheaper, in utilizing wastes, or in starting from cheaper raw materials.

There are but two kinds of industries: (a) Those which are based on processes which change the form of matter, such as the manufacture of furniture for example, and (b) those which are based on processes which change the composition of matter, such as the manufacture of Portland cement from clay and limestone. Now group “b” comprises 343 by far the greatest number of industries, and since the science of chemistry concerns itself with just those changes in the composition of matter, it is evident that most of our industries are chemical in their nature. We have but recently come to realize this. A list of such industries and operations which are essentially chemical would be found to include almost every industry that we can think of. I need only make mention of the subject of fuels, gas and coke, of cement, mortars, brick and other building materials; of petroleum and its products; of asphalt; of the products of the destructive distillation of wood; of cellulose and of paper; of pigments, resins, varnishes; of rubber; of soap, fats and the fatty oils; of gums; of sugar and of starch; of the textile industries and of the dyes; of leather and glue; of explosives; of the heavy chemical industries, the manufacture of acids, alkalies and salts; of the manufacture of glass and the ceramic industries; of the fermentation industries; of the manufacture and standardization of medicines; of the subject of soils and artificial fertilization; of the subject of foods, and of nutrition; of the subject of water, sewage and sanitation; of photography; of all the electro-chemical industries and processes; of the production of steel, of copper, of lead and of all the other metals. I need only mention this formidable array of subjects and industries to convince the most sceptical one that chemistry does in fact, concern us, directly or indirectly, in all of our activities.

As I have said previously, chemistry influences industry in two distinct ways: First, in the discovery of new substances and new processes; secondly, in the perfection of known substances and known processes. In either of these fields the chemist is proud of his record. The conquests are so numerous that he is at a loss as to how or where to begin if he would tell of them. The whole field of industrial chemistry is one succession of chemical achievements, mammoth industries that had their humble birth in the chemist’s test 344 tube, his beaker, or his retort; the wealth of by-products saved to the world from what was a few years ago sheer waste; and above all increased efficiency in the manufacture of all products. The chemist does not claim more than his due when he points out that his activity covers the whole field of our daily experiences, and that his activity has always been for the lessening of waste, for greater efficiency, in a word, for the development of civilization. To illustrate the points which have already been brought out, the story of the soda industry, the beginning of the modern chemical industries, can be used. The beginning is far back in another century, so intimately is the development of the soda industry bound up with the advance of civilization.

The value of what we now call the alkalies as detergent substances, was known from the earliest times. The first alkali recorded in history is burned lime, and was called “caustic” on account of its characteristic property. Caustic lime is but slightly soluble in water, hence its use is greatly limited. History fails to tell who it was who first solved the problem of making a more soluble alkali, but some one, early in the Middle Ages, discovered that by the action of caustic lime on the so-called potashes, the ashes which remained on burning wood, a very soluble caustic was formed. And to this, the long since forgotten chemist gave the name “caustic potash.” The chemistry of the discovery is as follows: All plants take potassium, a very light metal, in some form or other from the soil, to form the so-called mineral, or bony structure, in other words the skeleton, of the plant. When these plants are burned the potassium in the form of a salt, chiefly potassium carbonate, is formed in the ash. These potassium salts can be extracted by water, and recovered on the evaporation of the water. These potassium salts, the so-called “potashes,” were extensively used in the industries of the time, for example, in making soap, in making glass, in dyeing and in a score of 345 other minor ways. But even as our forests cannot now meet the demand for timber, so they could not then meet the demand for the “potashes,” for it requires a large amount of wood to give a comparatively small amount of potashes, the percentage of potassium salts in wood being very small indeed. Simultaneously with all this, in northern Spain, on the seacoast, a number of towns were engaged in burning sea weeds. It was found that the ashes of sea weeds while not the same as potashes, nevertheless could be substituted for them. This is historically recorded as the “barilla” industry. Barilla consisted of 5 per cent of carbonate of sodium, a metal very similar to potassium. Sodium does for sea plants just what potassium does for land plants. Barilla was merely a substitute for potashes, and a very poor substitute at that. But it was destined to offer the key that solved the whole problem. The chemists of that time showed the chemical similarity between the active ingredient of potashes, carbonate of potassium, and the active ingredient of barilla, carbonate of sodium. The demand for these alkalies made by the industries was incessant and ever-increasing. The chemists realized that the direct natural sources of the two, namely, the wood of the forest and the weeds of the sea, were and always would be, inadequate to meet the enormously growing demands of the industries. They saw that some other source would have to be discovered, or the bodies would have to be prepared artificially. They realized that while potashes were better than barilla, nevertheless potassium salts, the ingredients of potashes, were much less widely distributed in nature than the sodium salts, the ingredients of barilla. So they set out with the definite object of preparing sodium carbonate. In 1791 LeBlanc took out a patent for his now famous process. He was not the only one who worked on the problem; he happened to be the successful one.