The Royal Commission on the collapse of the Quebec Bridge printed, in the eleventh appendix to its report, the letters and telegrams that passed between Norman McLure, the Quebec Bridge Company’s inspector of erection at New Liverpool on the south shore; Theodore Cooper, its consulting engineer, at his office on Broadway in New York; and John Sterling Deans, chief engineer of the Phoenix Bridge Company at Phoenixville, Pennsylvania, in the three weeks before the fall, from the first bent rib on 6 August to the last letter about it on the 27th. They are given here as the report gives them, in the order in which they were written, with the Commission’s own connecting sentences where it supplied them. Three short acknowledgements from Deans, of 10, 14 and 23 August, each saying only that a fuller letter would follow, are left out. Chord numbers follow the erection marks: “7-L” is the seventh lower chord of an arm on the left, or Montreal, truss, “R” the Quebec truss; “A” is the anchor arm.

6 August: McLure to Cooper

“New Liverpool, P.Q., August 6, 1907.

“Dear Sir,—In riveting up the splice between chords 8 and 7 in the west truss of south cantilever arm we found the condition of the inside ribs at splice as indicated in the following sketch (drawing No. 30).

“Owing to the limited space between the two inside ribs, it would be impossible to jack this splice back, and as the condition is not nearly as bad at the top of the splice, we have proposed putting a diaphragm between the two inside ribs to cover the first five rivets up from the bottom on each side of the splice, as indicated in red in the sketch above. The splice plates being riveted on the two inside ribs, it will be necessary to cut out and redrive twenty rivets to do this. This provision, together with the top and bottom cover plates, should be sufficient to hold this splice against the thrust due to its being out of line, which thrust when under its maximum compressive stress I estimate at not over 60,000 pounds.

“The Phoenixville office is being notified of this plan, and if they will approve will wire us. If this also meets with your approval, or if you wish to suggest another way to remedy the difficulty, will you please wire me at St. Romuald, P.Q., care Phoenix Bridge Company, as the riveting gangs are ready to finish riveting this splice.

“Very truly yours, N. R. McLURE.”

8 August: Cooper’s telegram to Phoenixville

“Method proposed by Quebec for splicing joints at lower 7 and 8 chords is not satisfactory. How did bend occur in both chords?”

9 August: Cooper to McLure

“Dear Sir,—Yours of the 6th regarding bent condition of lower 7 and 8 chord joint came yesterday. I wired Phoenix that the proposed method as sketched by you for repairing was not satisfactory. Also asked, what you should have reported, how did both these chords get bent?

“In my opinion these webs can be brought back to proper line by use of fifteen to twenty 1-inch bolts, threaded at both ends for nuts, passing through the two webs of that half of chord. Of course means must be taken to stiffen the straight web against its bending when the bolts are tightened.

“If necessary, after getting the bent webs in line, to hold them, spacers and possibly some through bolts may be used.

“Some more satisfactory method than the one shown in your sketch must be devised.

“Mr. Deans telegraphs that upon Mr. Szlapka’s return he will give me fuller facts.

“Yours truly, THEODORE COOPER.”

9 August: Deans’s telegram and Cooper’s letter to Deans

Deans had wired: “Mr. Szlapka happened to be at bridge site yesterday; expect him home to-morrow, with full information concerning chord joint; will then write you fully.” Cooper replied the same day.

“Dear Sir,—Your telegram regarding chord joint at hand. The method proposed as sketched by Mr. McLure is not satisfactory as I telegraphed yesterday.

“These bent webs can be pulled back by use of about fifteen to twenty 1-inch bolts (in 1⅛-in. holes) threaded at both ends for nuts, passing from the outer to the inner bent web. The outer straight web being stayed in some manner against its bending.

“If the bent webs after being pulled into line, tend to go back when released from the bolts, stays must be introduced to hold them in position. Possibly it may be necessary to permanently rivet in some of these 1-inch bolts.

“Please let me know what method you propose to use.

“It is a mystery to me how both these webs happened to be bent at one point and why it was not discovered sooner.

“Yours very truly, THEODORE COOPER.”

12 August: Deans to Cooper

“Dear Sir,—Chord splice south cantilever arm, 7 L and 8 L.

“Mr. Szlapka reached the office this morning and I am able to give you information in connection with this one joint.

“All ribs of the chord 7 L have a complete and full bearing on ribs of 8 L. The bend was no doubt put in the rib in the shop, before facing and was probably done when pulling the ribs in line to make them agree with spacing of these ribs and the clearance between ribs, called for on the drawing. The bend being on only one rib of one chord, there being a full bearing over the entire rib, all splice plates being readily put in position, we do not think it necessary to put in the diaphragm suggested by the erection department.

“Please let us hear from you on this subject promptly, and oblige.

“Yours truly, JOHN STERLING DEANS, Chief Engineer.”

12 August: McLure to Cooper

“Dear Sir,—I beg to acknowledge the receipt of your letter of August 9 and have noted what you say regarding the method of repairing splice between chord 7 and 8 cantilever arm west truss. We will not do anything with this then until the matter has been arranged between yourself and Mr. Szlapka.

“The reason I did not report at first as to how these chords got bent was because there were many different theories here as to the cause, no one of which I was at that time ready to accept. One thing I am reasonably sure of, and that is that the bend has occurred since the chord has been under stress, and was not present when the chords were placed. This being the case, the cause of the bend would seem to be the slight overrunning in length of the bent rib in either chord 7 or 8. Owing to the fact that these chords are faced on the rotary machine the four ribs at once, this would at first seem to be out of the question, but it seems to me that after the first end of a chord has been faced in turning it with the crane, to bring the other end into position for facing, it might be possible for one rib to work slightly by the others longitudinally, without being noticed, and in spite of the latticing and thus cause a slight difference in length. In fact, in taking the opening in the chord splices on the south anchor arm, it has often been noticed that a considerable variation existed between the openings of the different ribs at the same splice, which difference I was not able to account for except by the above theory that, during transportation, and in the handling before erection, some of the ribs have worked slightly in a longitudinal direction by each other. In the case in question, of course, this must have happened between the time of facing one end and the other. If this is correct, then it will be a pretty hard matter to draw the splice back into line with bolts, and our idea in suggesting that diaphragm was to prevent this eccentricity from increasing, rather than to correct that already there.

“As I had supposed, the strike in force for the last three days of last week, has been settled and work was again resumed this morning. A meeting of the ‘Union’ was held Saturday night and enough of the discontented element had been lost so that when the matter was brought to a vote the majority were found to be in favour of returning to work under the original agreement. Those who were not in favour of returning to work, however, are now leaving so that our force is reduced greatly on both sides of the river.

“Since writing the above I have discovered that splice between the chords 8 and 9 on west truss of south cantilever arm is in the same condition exactly as that between 7 and 8, except that the bend is only ⅜-in. instead of ¾-in. at the bottom, and runs out so that on top this rib is in line as are the other three.

“This is the same rib, and the bend is in the same direction as that reported for the other splice. When it is decided in what way to treat the splice between chords 7 and 8 we will repair that between chords 8 and 9 in a similar manner.

“Yours very truly, N. R. McLURE.”

13 August: Cooper to Deans, and to McLure

To Deans: “Dear Sir,—The information regarding chord splice 7 and 8 L, is so different from the dimension sketch sent by Mr. McLure, I can take no action on this matter till the exact facts are presented. Please have your resident engineer and Mr. McLure re-examine this joint and send the exact condition of this rib, as to the amount of the bends and relation of the bearing surfaces to each other.

“I don’t see how one rib being bent, only, as stated in your letter, there can be a complete and full bearing of these ribs.

“Neither can I understand how pulling the ribs into line at the shop could bend it out of line.

“I will write Mr. McLure to-day to have a further investigation of this joint and to report as promptly as possible.”

To McLure: “Dear Sir,—Mr. Deans writes me that only one rib at joint 7 and 8 L is bent, and still that there is a full and complete bearing, that the bend was no doubt put in the chord in the shop before facing.

“I have asked him to instruct his resident engineer to join with you in making an exact report, with dimensions of the conditions of this joint, with amount of bearing and if it is a square bearing or askew.

“In reference to the splicing of T-5 and T-5 O mentioned in your letter of 10th, I do not care to interfere with the regular programme as I have not followed the various actions of the loadings at different stages. Without going into it carefully, I think there will be more compression at these points with more of the suspended span in place.

“Please report promptly regarding joint 7 and 8-L with all the facts.”

15 August: Cooper to McLure

“Dear Sir,—None of the explanations for the bent chord stand the test of logic. I have evolved another theory, which is a possible if not the probable one. These chords have been hit by those suspended beams used during the erection, while they were being put in place or taken down. Examine if you cannot find evidence of the blow, and also make inquiries of the men in charge.

“Yours very truly, THEODORE COOPER.”

16 August: McLure to Cooper

“Dear Sir,—Referring to your letter of the 13th, regarding splice between 8-L and 7-L on south cantilever arm, you have no doubt by this time received my letter of the 12th instant, giving my theory of the cause of this bend. These conditions are as indicated in my report of August 6. Mr. Birks, the resident engineer for the Phoenix Bridge Company, reported exactly the same thing, in somewhat different language to Phoenixville, but Mr. Deans has evidently taken a different meaning from his report than was intended. He evidently thinks that only one rib of one chord is bent, whereas it is the same rib of each chord, as indicated in the sketch I sent you. There is really nothing to add to the two letters I have already written regarding this bend, except to say that all the four ribs have full bearing on each other, as indicated also in the sketch of August 6. In order to verify our first reports, Mr. Birks and I made a careful and more thorough measurement of this splice to-day, both top and bottom, and I am inclosing a blue print of a sketch made as a result of these measurements. It indicates practically the same condition as described in my first letter, except that it is given more in detail (see drawing No. 30).

“As to the cause of this bend, regarding which I wrote you on August 12, Mr. Deans seems to think that it was put in in the shops; but that is because he did not understand the conditions existing. Aside from the fact that it would be hardly probable that these two ribs of different chord sections should be bent the same way, exactly the same amount in the shops to dimensions ⅜-inch to ¾-inch less than called for; I am reasonably sure, as I said before, that this condition did not exist before the erection of these chords, as I have personally inspected every member yet erected in this bridge thus far, except the bottom chords of anchor arm, on the cars just before the erection, looking particularly for bends in ribs of compression members, and wherever discovered have taken measurements of the amounts and recorded them. If these ribs then had been this much out of line before erecting, it would be well nigh impossible to miss seeing them. Consequently the only way the bend could have occurred, it seems to me, is that reported in my letter of August 12.

“I trust that these explanations, with the inclosed sketch, will make the matter entirely clear. Mr. Birks is sending same sketch to Phoenixville to-day.

“Yours very truly, N. R. McLURE.”

20 and 21 August: Deans to Cooper, Cooper to Deans

Deans, on the 20th: “We have advice from your field that you received copy of sketch No. 28, giving further details in connection with cantilever chord splice 7-L and 8-L. You will notice that the two chords have a perfect bearing with each other at all ribs; both chords having one bent rib and not one chord only as we first understood.”

Cooper, on the 21st: “Dear Sir,—I received copy of sketch of joint 7 and 8-L two days ago.

“I wrote Mr. McLure last week, telling him none of the theories as to how this bending occurred were logical. That my theory was a blow on this rib after the two sections were in contact, and that it probably was done in moving the suspended beams used in erecting. To examine carefully to see if he could find any evidence of this; he has not yet reported. He did report a similar bend at L-8 and 9 west truss in same rib but of less amount.

“I still believe this bend can be partly removed by use of long bolts with threads at each end, outer rib being stiffened to prevent its bending. If it can be pulled nearer straight, stays or bolts must be provided to hold it against future movement.

“I cannot consent to let it go without further action as the rivets in the cover splices would not satisfy the requirements to my mind.”

26 and 27 August: Cooper to Deans, Deans to Cooper

Cooper, on the 26th: “Dear Sir,—Mr. McLure reports that he can find no evidence of the bent ribs having been hit and does not think they could have been struck. This only makes the mystery the deeper, for I do not see how otherwise the ribs could have been bent.

“When convenient I would like to discuss with Mr. Szlapka the best means of getting these ribs into safe condition to do their proper work.”

Deans, on the 27th: “Chord splice 7 and 8 cantilever arm, south side. Replying to your letter of August 26th, I will have Mr. Szlapka call to see you first opportunity, to discuss this question. He will wire you later the day he will be in New York.”

The Commission: “This was the last that transpired with regard to the bent ribs at joint 7-L and 8-L cantilever arm, and it is plainly indicated that no one except Mr. Cooper looked upon this matter as serious or as indicating any constitutional weakness.”

What followed, from McLure’s letter of 27 August with the two measurements to the telegrams of the 29th, is in the companion piece “The last three days”.

Sources

• Royal Commission on the Collapse of the Quebec Bridge, Report, Sessional Paper No. 154, Ottawa, 1908, Vol. I, Appendix 11, “A discussion of the difficulties that arose during erection and of the events at the time of the collapse of the structure”, pages 79 to 86, from which every letter and telegram above is taken. archive.org