Failures of Ferro-Concrete. THEY ARE MANY AND FORMIDABLE.

Progress, Volume III, Issue 9, 1 July 1908, Page 311

Failures of Ferro-Concrete. THEY ARE MANY AND FORMIDABLE.

Mr. G. A. Iyewis has written an emphatic warning on the above subject. We re-publish with pleasure. — Just now we are hearing and reading about the above material for building construction. In almost every building, and technical journal that one may take hold of its praises are being sung, so I thought a few words on some of its failures, that our friends on the other side of the Altantic have

experienced might be read by some of our readers with interest, especially by those who do not know that some ot these glowing reports do not quite represent the lacts of the matter. Reinforced concrete has only lately been adopted for the construction of some of our public buildings in this country, and we have not had much time to witness its shortcomings. We must, therefore, go for experience to a country where it has been very much in use. Since the San Francisco earthquake and fire, there has been no subject of greater importance to all interested m the construction of buildings than the compari-

tive merits of brick and concrete. That catastrophe created new problems, and presented new conditions. Certain interests have taken advantage of the changed aspect to set forth theories and statements, neither fair, honest, nor truthful, selfishly attacking brick as a building material. The truth hurts no sound reliable article. Brick and terracotta stand out as far and away the best building material as regards durability, substantiality, and fireproof qualities. Herein lies the truth. The cement interests have been active in filling the magazines and the daily press, with technical papers by their

own engineers and writers, exalting their own product, and belittling brick and other material I hope now to correct any misapprehension in the minds of the building public, by a few illustrations of buildings that have collapsed.* Actual photographs tell the truth and I hope they will be conclusive enough to establish the reliability and superior character of brick as a building material, against its rival concrete. I simply ask that the truth be known. Referring to the concrete craze, people often ask why

* We have seen the pictures, which show a very complete rum. Unfortunately their lack of defimLeness prevents their reproduction. — [Bd. " P-"j

it has aroused such an interest, particularly among the younger and less experienced structural engineers. Well, as anyone knows, anything in an experimental stage is bound to be attractive to young engineers and architects. I admit the whole subject of reinforced concrete is a most fascinating one about which to theorise. The greatest difficulty with it generally is to apply those theories in actual construction, and there, of course, is the scene of its failures. Anything that makes a great noise, and is being much talked about, is bound to obtain some popularity. To my

mind, however, the principal reason for this, at least temporary, popularity, is the extreme activity of the exploiters of its hundred or more different systems. The technical journals are over-loaded with scientific discussions as to its modules of elasticity, and the manufacturers and patentees of the various systems keep all the technical schools and engineering colleges loaded up with tests, reports, and what not concerning their varied products. Naturally enough the colleges turn their attention to the subject, learned professors do some experimenting on their own account on a small scale, and proclaim to the world, that

this is so, and must remain so under every circumstance, and I am sorry to see that we in this country are swallowing their misrepresentations. Now, in connection with a comparison of costs as regards the different materials, it is often said that reinforced concrete is cheap ; and when concrete is cheap, it has to be "cheap" in every sense of the word. Inferior cement, the least possible quantity of that, and cheap unskilled labour, are the constituent elements of its cheapness, and with these factors, what can be expected of the concrete ? But still in this country it might be given more than its required quota of cement, and also extra supervision, even if its promoters lose money over it, just to firmly launch it on the unsuspecting building public. That done they could gradually relax the extra precaution, that it needed to give it a good send off. Reinforced concrete is said to be fire-proof, but everyone connected with the building industry knows that it is not, for where it has come in contact with fire it has been an utter failure. When a heat of 600 degrees and upwards reaches it, it loses its water of crystalisation until the water is finally driven off ; the cement or concrete will lose most of its strength ; in fact will be ruined. As an illustration, a fire occurred at the Monadnock building, San Francisco, and after it was extinguished, a pile of empty sacks, and also loose timber that was lyirg aboat, had sustained little or no damage, while the reinforced concrete beams and floor were a total wreck, though they showed they had been subjected to very little heat. Not only had this building been constructed by the best formula, with Johnson bars turned up at the ends, which is supposed to resist severe strains, but it also showed that concrete and steel do not expand and contract together. This is only one instance ; I might quote others, but I must consider space. Now it has been said that the concrete adheres to the steel bars that are used as reinforcements. Well, in the case of buildings that have collapsed in course of construction, the steel bars have failed to show it, as they have come out perfectly clean, as if they had never been in close proximity to cement. These are facts. The Hotel Bixby, I v ong Beach, Cal., is a warning to those who have only looked on one side of the construction. This building collapsed on Friday morning, November 9, 1906, without a word of warning', and killed ten men outright, while as many more were seriously injured. This building

was constructed by the most up-to-date method known in reinforced concrete, chieffy of the Kahn bars, recognised among reinforced concrete engineers as being the best and highest priced reinforcements on the market, though Ransome twisted bars and

square and round bars w ere used in columns, and in some parts of the building. A provision had also been made in part of the exterior columns for any settlement that might take place on any one pier, by connecting the piers together at about the surface line, with a reinforced girder, assuming that this would act as a cantilever, and prevent any one pier or piers from settling. Yet, in spite of all these precautions, this building collapsed with fatal results. Here are the names of a few of the towns where concrete buildings have recently collapsed. — Elyria, Ohio; Minsola, I v I. , Rochester, N.S, , Marshall, I.U. ; La Ciosse' Wis. ; Dubeth, Mm. ; Trenton, NJ. , Newcastle, P. A ; Milwaukee, Wis , Dayton, Ohio , Pittsburg, P. A. , Greenpoint, N.S ; Binghamson, N.Y. ; Corning, N.Y. , Boston, Mass. , Philadelphia, Bridgeman Bros building , Pe^ria, 111., a 200 tt. concrete chimney Berne, Switzerland ; Paris, France . These

are only a few among the many disasters that have occurred recently. Now, I hope I have said enough to convince anyone interested in ferro, or reinforced, concrete, that it is not all that its promoters make it out to be.