The Royal Commission appointed to inquire into the collapse of the Quebec Bridge, Henry Holgate, John G. G. Kerry and John Galbraith, signed its report at Montreal on 20 February 1908, six months after the fall. The report proper is eleven pages; the evidence and the nineteen appendices fill two volumes. This piece gives the findings as the commissioners wrote them, the passages of the eleventh appendix in which they judged what was done at the bridge in the last three days, the summary of the government’s own check of the stresses, and the two answers in which Cooper, in writing from New York, declined to accept that nothing could have been done.

The findings

“Your commissioners find:

“(a) The collapse of the Quebec bridge resulted from the failure of the lower chords in the anchor arm near the main pier. The failure of these chords was due to their defective design.

“(b) The stresses that caused the failure were not due to abnormal weather conditions or accident, but were such as might be expected in the regular course of erection.

“(c) The design of the chords that failed was made by Mr. P. L. Szlapka, the designing engineer of the Phoenix Bridge Company.

“(d) This design was examined and officially approved by Mr. Theodore Cooper, consulting engineer of the Quebec Bridge and Railway Company.

“(e) The failure cannot be attributed directly to any cause other than errors in judgment on the part of these two engineers.

“(f) These errors of judgment cannot be attributed either to lack of common professional knowledge, to neglect of duty, or to a desire to economize. The ability of the two engineers was tried in one of the most difficult professional problems of the day and proved to be insufficient for the task.

“(g) We do not consider that the specifications for the work were satisfactory or sufficient, the unit stresses in particular being higher than any established by past practice. The specifications were accepted without protest by all interested.

“(h) A grave error was made in assuming the dead load for the calculations at too low a value and not afterwards revising this assumption. This error was of sufficient magnitude to have required the condemnation of the bridge, even if the details of the lower chords had been of sufficient strength, because, if the bridge had been completed as designed, the actual stresses would have been considerably greater than those permitted by the specifications. This erroneous assumption was made by Mr. Szlapka and accepted by Mr. Cooper, and tended to hasten the disaster.

“(i) We do not believe that the fall of the bridge could have been prevented by any action that might have been taken after August 27, 1907. Any effort to brace or take down the structure would have been impracticable owing to the manifest risk of human life involved.

“(j) The loss of life on August 29, 1907, might have been prevented by the exercise of better judgment on the part of those in responsible charge of the work for the Quebec Bridge and Railway Company and for the Phoenix Bridge Company.

“(k) The failure on the part of the Quebec Bridge and Railway Company to appoint an experienced bridge engineer to the position of chief engineer was a mistake. This resulted in a loose and inefficient supervision of all parts of the work on the part of the Quebec Bridge and Railway Company.

“(l) The work done by the Phoenix Bridge Company in making the detail drawings and in planning and carrying out the erection, and by the Phoenix Iron Company in fabricating the material was good, and the steel used was of good quality. The serious defects were fundamental errors in design.

“(m) No one connected with the general designing fully appreciated the magnitude of the work nor the insufficiency of the data upon which they were depending. The special experimental studies and investigations that were required to confirm the judgment of the designers were not made.

“(n) The professional knowledge of the present day concerning the action of steel columns under load is not sufficient to enable engineers to economically design such structures as the Quebec bridge. A bridge of the adopted span that will unquestionably be safe can be built, but in the present state of professional knowledge a considerably larger amount of metal would have to be used than might be required if our knowledge were more exact.

“(o) The professional record of Mr. Cooper was such that his selection for the authoritative position that he occupied was warranted, and the complete confidence that was placed in his judgment by the officials of the Dominion government, the Quebec Bridge and Railway Company and the Phoenix Bridge Company was deserved.”

The last three days

From the eleventh appendix, after the letters of 27 and 28 August:

“It was clear that on that day the greatest bridge in the world was being built without there being a single man within reach who by experience, knowledge and ability was competent to deal with the crisis. Mr. Yenser was an able superintendent, but he was in no way qualified to deal with the question that had arisen. Mr. Birks, well-trained and clear headed, lacked the experience that teaches a man to properly value facts and conditions; and Mr. Hoare, conscious that he was not qualified to give judgment, simply assented to the courses of action that had been determined on by Messrs. Yenser and Kinloch and made no endeavour to make a personal examination of the suspected chords.

“Some measurements were made to test the stability of the main pier, but no one seems to have thought of testing the span for alignment or levels, and, above all, to measure the chords again to see if they showed any increase of deflection.”

On the morning of 29 August: “From the time that these assurances were received, anxiety at the bridge practically ceased, and there is no evidence that any further measurements were made to determine the movements of the suspected chords. As Mr. Hoare expressed it, ‘I felt quite comfortable that day about it. I knew it could not be long before the matter would be taken up.’”

On Cooper’s telegram: “This message was received at Phoenixville at 1.15 p.m. Mr. Cooper has explained in his evidence that he was not aware at the time that erection was proceeding, Mr. McLure having advised him to the contrary, and that he telegraphed to Phoenixville instead of to Quebec because he thought action would be more promptly secured by so doing.

“Mr. McLure had promised to wire Mr. Cooper’s decision to Mr. Kinloch immediately, but he did not do so.

“Mr. Deans reached his office about 3 p.m., and found Mr. Cooper’s telegram there. He arranged for Mr. Szlapka and Mr. Milliken to be on hand to meet Mr. McLure, but otherwise took no action. After Mr. McLure arrived there was a brief discussion, during which Mr. McLure mentioned that he had received a wire from Mr. Birks giving him the result of that gentleman’s observations on August 28. It was decided to postpone action until the morning, and to await the arrival of Mr. Birks’ letter of August 28. This decision was made almost at the minute that the bridge fell.”

On the cause: “As a conclusion reached from the evidence and from our own studies and tests, we are satisfied that the bridge fell because the latticing of the lower chords near the main pier was too weak to carry the stresses to which it was subjected; but we also believe that the amount of those lattice stresses is determined by the deviation of the lines of centre of pressure, from the axis of the chords, and this deviation is largely affected by the conditions at the ends of the chords. We must, therefore, conclude that although the lower chords 9-L and 9-R anchor arm, which, in our judgment, were the first to fall, failed from weakness of latticing; the stresses that caused the failure were to some extent due to the weak end details of the chords, and to the looseness, or absence of the splice plates, arising partly from the necessities of the method of erection adopted, and partly from a failure to appreciate the delicacy of the joints, and the care with which they should be handled and watched during erection. We conclude from our tests that owing to the weakness of the latticing, the chords were dangerously weak in the body for the duty they would be called upon to do.”

On the men: “We consider that Mr. Deans was lacking in judgment and in sense of responsibility when he approved of the action of Mr. Yenser in continuing erection, and when he told Mr. Birks and Mr. Hoare that the condition of the chords had not changed since they left Phoenixville.

“No evidence has been produced before the commission in proof of the correctness of this statement about the chords, and Mr. Szlapka’s calculations as stated in the following letter showed that the rivets were even then loaded to their maximum specified stress of 18,000 pounds per square inch.” The Commission asked Phoenixville in January 1908 for the calculation Szlapka had made on 29 August; it was supplied, and the Commission observed: “The theory underlying these calculations is very questionable, but it was adopted in the design of the bridge (See Appendices Nos. 16 and 17) and we cannot understand why its warning was so entirely disregarded in the face of the consequences that might result.

“With reference to Mr. Cooper’s telegram, Mr. Deans knew that he was in possession of later information from the bridge than had reached Mr. Cooper and therefore decided to wait for Mr. McLure and afterwards for the arrival of Mr. Birks’ letter of August 28 before taking action. The whole incident points out the need of a competent engineer in responsible charge at the site.

“Mr. Hoare was the only senior engineer who was able to reach the structure between August 27 and August 29. He was fully advised of the facts yet did not order Mr. Yenser to discontinue erection which he had power to do; we consider that he was in a much better position than any other responsible official to fully realize the events that had occurred, and his failure to take action must be attributed to indecision and to a habit of relying upon Mr. Cooper for instructions.

“We are satisfied that no one connected with the work was expecting immediate disaster, and we believe that in the case of Mr. Cooper his opinion was justified. He understood that erection was not proceeding; and without additional load the bridge might have held out for days.

“Our tests have satisfied us that no temporary bracing such as that proposed by Mr. Cooper could have long arrested the disaster; struts might have kept the chords from bending, but failure from buckling and rivet shear would soon have occurred.”

Schneider on the stresses

C. C. Schneider of Philadelphia was engaged by the Department of Railways and Canals on 9 September 1907 “to inquire into and pass upon the sufficiency of the present design of the Quebec bridge”. He recomputed every stress from the shipping weights of the steel, and reported in January 1908:

“The strains in the trusses resulting from the live load agree with those computed by the writer. The strains from the dead load as computed by the writer, however, are greater than those shown on the diagram submitted by the Phoenix Bridge Company, for the reason that the actual weight of the steel superstructure is in excess of that estimated previous to its construction.”

“By examination of this table, it will be noticed that the actual unit strains in most of the members of the trusses exceed the limits of the specifications. In the upper chords of the cantilever arm (excepting in the panels from U2 to U6, which were proportioned for the erection strains), from 10 to 18 per cent; and in the lower chords (with the exception of the panels from L0 to L4, which were also proportioned for the erection strains), from 7.5 to 24 per cent. In the upper and lower chords of the anchor arms, the unit strains in all panels exceed these limits from 11 to 20 per cent. The unit strains in the chords of the suspended span also exceed the limits of the specifications: the upper chords 16 to 18 per cent; the lower chords from 7½ to 9½ per cent. While the strains in some web members come within the limits, in some cases they are in excess as much as 21 per cent, and in one case 67 per cent. The trusses, therefore, as designed, do not conform in this respect to the requirements of the specifications approved by the government.”

Cooper’s answers

The commissioners put their questions to Cooper in writing in New York in October 1907, and again in December. Among them:

“Q. Do you consider that there was clear indication that the failure was imminent and was it possible, by prompt and intelligent action, to have prevented the failure?—A. I think the deflection of an important member, as chord 9 west, to the extent of 2¼ inches would indicate to any intelligent mind that that chord was less capable of doing the duty that it would have done if in a perfectly straight condition, and I do think that it was perfectly possible by prompt and intelligent action to have stayed that chord and prevented the failure of the bridge.

“Q. By whom should the orders for such action have been given and to whose lack of judgment and initiative can the failure therefore be charged?—A. To the executive officers of either company who were present or within sufficient touch to have given any orders.

“Q. In your opinion, is it good practice to leave the ordering of such action to any employee of a contracting company?—A. The contracting company should have had on the structure an employee of sufficient intelligence to have appreciated the necessity for and to have given such an order. At the same time, the responsible executive of the Quebec Bridge Company should not have hesitated, in the absence of proper action by the contractor, to have given such an order.

“Q. Do you think that at moderate expense the ribs could have been made absolutely safe?—A. I do. I believe if prompt action had been taken to protect chord 9 west from further deflection, which could have been done by the employment of three hours’ work and $100 worth of timber and bolts, the defects and deficiencies which we now recognize in the compression chords and members, could, at a later date, have been corrected and the bridge could have been made perfectly safe and efficient for its intended purpose.”

Asked in December to explain the hundred dollars, he described a strut from the crossing of the lateral braces to the middle of the chord, “a timber strut formed of about four 12 x 12’s about 30 feet long, properly spaced apart, so as to make a wooden strut perfectly capable of resisting one hundred tons, which I estimated was the theoretical force to be resisted at the centre of this chord, bent as shown. Whether this would cost $100, more or less, is a matter of very small importance.”

And asked why he had telegraphed Phoenixville and not Quebec: “During the half hour that I had this matter under consideration I felt that prompt action was needed to stop any more loading and to promptly protect the chord from further deflection. Learning from Mr. McLure that there was no one upon the work but the foreman, realizing that it might be very slow reaching Mr. Hoare, as he might be at his home, his office, the bridge or some other place, I decided that the shortest and quickest method of reaching the bridge was through the Phoenix Bridge Company, who, I knew, had direct wire and telephonic communication with their office at the bridge. On the previous occasion when I stopped work on the bridge by communicating with the chief engineer of the Quebec Bridge Company there was no emergency before me.”

“Q. Do you consider that the engineering data at our disposal are sufficient to enable engineers to design members similar to those in the lower chord with safety and economy? Would you now recommend any material changes in the detailing of these or any other members, and, if so, what would these changes be?—A. My responsibilities, gentlemen, end as soon as I have served my duty of aiding you in reaching the truth in regard to the destruction of this bridge. While I have my views and such views are at the service of those who have heretofore relied on me, I shall decline to take any executive or responsible position in connection with the correction of the errors that we now recognize in this work; it must be referred to younger and abler men.”

Sources

• Royal Commission on the Collapse of the Quebec Bridge, Report, Sessional Paper No. 154, Ottawa, 1908, Vol. I: the report to the Governor General, pages 7 to 11, for the findings; Appendix 11, pages 90 to 93, for the passages on the last three days and on Deans, Hoare and Cooper; and C. C. Schneider, Report on Design of Quebec Bridge, January 1908, pages 153 and 154. archive.org
• Royal Commission, Minutes of Proceedings and Printed Exhibits, Vol. II, 1908: Cooper’s testimony of October 1907, pages 355 and 356, and his re-examination, pages 412 and 413. archive.org