Ego in Engineering: The Quebec Bridge Collapse

in 1907 lacks oversight miscalculations and cost cutting in design led to one of the worst construction disasters in canada's history [Music] when we think of structural engineering architecture and construction work it's not often that these terms are used in the same sentences gross miscalculations neglect of dead load factors or financially troubled design but in august of 1907 after seven years of construction the nearly completed southern half of the in-progress quebec bridge with 75 workers toiling away high on its framework collapsed suddenly and without warning the saint lawrence river roughly two miles wide even at its narrowest point had long been the main route of trade for quebec prior to 1919 during the summer the only way to cross from the south side to the north was to take the ferry during the cold months however once the river became impassable by boat all crossings and trade were cut off in the long wait for it to ice over entirely at this point an impromptu wintertime icebridge would be established for quote vehicular crossings which was both not ideal and inherently dangerous as far back as the 1850s there had been local interest in resolving the issue of crossing the saint lawrence but the project didn't start gaining steam until the late 1880s local political leaders and businessmen came together at this time to form the quebec bridge committee the heightened interest gained the attention of canadian parliament passing an act incorporating the committee into a company until a site had been selected though the newly formed quebec bridge company's requests for government funding were declined after several long years of debate and once preliminary site surveys had been made the site where the bridge stands now was chosen this lack of funding combined with the quebec bridge company seemingly shoestring budget would creep its way into all aspects of the project it was decided by several experts in the industry that a bridge of this magnitude would need to be of cantilever design and not a suspension bridge after all it was expected to be capable of carrying rail vehicle and foot traffic the very first cantilever bridge was brought from concept to reality in 1867 in germany only 30 years prior and throughout those years only roughly four more would be constructed before the quebec bridge had been undertaken at a length of 1800 feet from north span to southspan revised from an already massive 1600 feet it would be the longest and largest cantilever structure ever attempted by that time the quebec bridge company had no one experienced in anything longer than 300 feet and thus needed to bring on a consulting engineer a man named theodore cooper cooper an independent consultant that operated from new york city was considered quote one of america's foremost bridge builders of his day and for him personally this project was to be the crown jewel of his entire body of work cooper now fully in charge of the project would sign off on the need for a cantilever design as well and interesting fact here even gustav eiffel yes that eiffel was briefly consulted and also found the cantilever to be the best solution proposals would now need to be received and reviewed from the start though cooper had been in close communication with the phoenix bridge company they'd submitted proposals and were chosen for the superstructure some speculate in a quote contest that was unfairly predetermined and the substructure would fall to the davis firm cooper hamstrung by the later revealed notoriously tight budget of this project i hereby conclude and report that the cantilever superstructure plan of the phoenix bridge company is the best and cheapest plan and proposal submitted to me [Music] collapses like this are rarely boiled down to one root cause deflection in engineering terms is basically when forces on load-bearing structures begin causing them to bend typically a limit to the amount of deflection is calculated prior to construction rarely do load-bearing structures not bend and give at least a little but when there is deflection outside of planned tolerances especially in crucial portions of a structure there is cause for concern especially those performing daily tasks on a project like the quebec bridge will have a keen eye for deflections that look out of place after a groundbreaking ceremony in october of 1900 the davis firm would begin work on the substructure completing this portion by 1902 it wasn't until july 1905 that the phoenix bridge company would begin work on the superstructure and they'd agreed to have their work completed by end of year 1908 being july of 1905 already two and a half years especially at the time was an absolute time crunch for a project of this scale beginning on the south side supervisors and workers began noticing significant deflections in main beams or chords those main support beams in tension and compression on top of this pre-drilled holes in the steel beams weren't lining up when attempting to rivet and these cords had to be forced into place to allow for fastening and then deflection began to increase theodore cooper whose health was ailing prior to this project already would remain in new york overseeing the construction and design only via correspondence and never visited the site in person he would receive reports from his eyes and ears on the project norman mcclure a young upstart engineer cooper's protege and personal onsite inspector these first few deflections didn't raise any red flags initially being chalked up to the steel having been bent in fabrication or in transit to the job site adding to this the chief design engineer for the phoenix bridge company peter schlapka also insisted these bends took place during fabrication at their shop important to note here is later it was discovered this chief design engineer admitted he never laid eyes on these chords beforehand then just a few months later more chords began showing signs of deflection once informed of this cooper began to form his own theories insisting the bending beams to be inspected for damage that he was now convinced took place while raising them into position carrying out this accusatory investigation mcclure found no evidence of any such damage less experienced engineers and workers on site continued to note these abnormalities but were still not alarmed reassured by project leaders and chalking it up to pre-existing conditions in the metal still concerned mcclure continued to pursue the issue as the deflections had indeed occurred after the beams were installed several workers had even began to remain off-site concerned enough by the bending and deforming beams now to not report in for work cooper though still disagreed and mcclure was lacking the experience and confidence to openly contradict the man and on cooper's orders work continued the amount of workers who had taken three days to protest these conditions was not insignificant and upon learning about the decision to move forward with construction status quo situation normal they left the project entirely reducing the number of workers now on the project significantly soon after though a construction foreman made the decision to halt work on the bridge anyhow as the main chords under close observation more than doubled their amount of deflection in the span of less than two weeks he insisted the matter be put under more serious review mcclure then left the job site bound for new york to seek advice from cooper in person with mcclure absent though the foreman who stopped the work initially was persuaded to change his mind by a note he received from the quebec bridge company's chief engineer that read the moral effect of holding up the work would be very bad on all concerned and might also stop the work for this season on account of losing the men the work resumed every moment that elapsed as work progressed meant more dead load being added to the structure dead load essentially being the weight of the structure itself that all load-bearing portions must support unaware this work had resumed mcclure met with cooper in new york and they reached the conclusion to pass along the following telegram to all phoenix bridge company crews add no more load to the bridge until after due consideration of facts this would finally declare a full stoppage of work at that point cooper however felt it prudent to wire the message to phoenix bridge company headquarters in phoenixville pa rather than directly to the worksite itself he assumed action would be taken more quickly and decisively if coming from the phoenixville office mcclure having finished his meeting with cooper was due to depart for the phoenixville office as well as he was expected for an in-person discussion there after his visit with cooper in new york noticing the need to get this message directly to the job site mcclure vowed to along his route to phoenixville stop and wire the telegram directly to the crews at the building site in his rush to the phoenixville office however this task slipped norman mcclure's mind work on the bridge had continued as the telegram to the phoenixville office when ignored the following day as mcclure's meeting with the phoenix bridge company at their headquarters came to a close the bridge completely collapsed with a thunderous roar under its own weight of the 86 workers present on the span only 11 were spared 33 of which from the mohawk nation of ganaway in the south of montreal this incident was one that garnered the first nations people such a well-regarded reputation as high steel workers one of the main chords a9 left the bent beam that had been worrying crews the most gave way first transferring the load to a9 right which also quickly buckled the peers of the substructure were all that remained standing as the entire superstructure disintegrated [Music] the investigation itself even gained renown as it pioneered many methods and facets of the newly developing practice at the time of forensic engineering the thoroughness and objectivity of their inquiry and report stand even today as models of their kind the royal commission report concluded the initial designs themselves were defective owing to gross miscalculation of stresses dead load and the fact that these designs were accepted without protest while the phoenix bridge company was not found liable in their fabrication of the steel members or weren't carried out on the structure as they had simply fabricated and worked according to the designs the royal commission did however state loss of life might have been prevented by the exercise of better judgment and overall supervision on the part of both the quebec bridge company and phoenix bridge company as for cooper his calculation managerial and ethical errors pointed out by the report were of the most concern when cooper had increased the decided total span from 1600 to 1800 feet between the two piers the weights of this change were miscalculated by as much as 10 percent and while 10 percent may not sound like much in this instance it meant an estimation by cooper of 62 million pounds total while the actual weight had the bridge been completed was closer to 73 million pounds an 11 million pound difference in the world of responsible engineering even back at that time had this discrepancy been caught it would have been enough to completely condemn the project instead in the rush of negotiations to keep the project alive this discrepancy was overlooked by both bridge companies being somewhat the first of its kind the largest cantilever structure ever conceived by that point little was known and how it would behave mechanically and due to such a low budget in the beginning the quebec bridge company lacked the means to perform any sort of adequate testing beforehand later into the project however the company did secure funds enough to perform testing and presented with this cooper rejected the ideas outright stating they had already wasted too much time in our table from before on assumed versus actual dead load these errors were discovered prior to the collapse however much of the construction had already been underway by that point and cooper accepted these heavier loads and stresses as quote being within acceptable limits knowing his options would be to abandon the project strengthen their already stressed supports or start over canada's government agency for railways and canals had also attempted to step in recommending a structural engineer that represented them to double check cooper's work and have final authority cooper the quebec bridge company and phoenix bridge company all objected to this idea outright cooper himself stating this puts me in the position of a subordinate which i cannot accept the railways and canals agency hadn't completely backed off at that point but their requests that all plans be submitted for approval by their own chief engineer were treated by cooper and both bridge companies simply as a formality and no plans were ever submitted collingwood schreiber the chief engineer for railways and canals did attempt to establish this new chain of command but due to cooper's vehement pushback cooper remained the final authority according to anyone carrying out the project looking back it appears that the workers who left the job site in protest were seemingly the very few amidst all this who recognized what was really happening and it's my personal experience from my career that engineers and members of management are often close-minded to the ideas of daily laborers and assemblers despite those assemblers having many years of hands-on experience and a keen eye when something seems out of place after this catastrophe the canadian government took over design and construction of the quebec bridge this also provided the much needed capital required to design and manage the project closer to the accepted standards of the time several experienced engineers were brought on even an engineer who had been involved in the fourth bridge in scotland the largest cantilever bridge ever created until a quebec bridge construction of this second albeit much more massive version owing to proper calculations had gone smoothly with both main spans north and south fully complete atop their respective peers in september of 1916 it was time to raise the final center span into place hoisted high above the water the center span snapped free from its lifting equipment and plummeted instantaneously back down into the river below claiming the lives of 13 more workers german sabotage was initially thought to blame as this was after all during the height of world war 1 in which canada was heavily involved the center span no slouch at 640 feet long 88 feet wide and weighing in at over 5000 tons required a very complex hoisting device and upon investigation it was apparent that portions of this device had failed concurrent with that of an accident and not sabotage it was however undoubtedly tragic for everyone involved the bridge was finally completed in august of 1919 and open once and for all to all traffic on december 3rd of that same year it was declared a national historic site in 1996 and there was a plaque dedicated for this purpose acknowledging in a single sentence the workers who'd given their lives in 1907 however it would be one hundred years later in august of 2007 when a memorial was unveiled on the gonawage nations reserve [Music] so you

Channel: Brick Immortar

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Keywords: the quebec bridge collapse a preventable failure, the quebec bridge disaster, theodore cooper quebec bridge, mohawk quebec bridge, mohawk steelworkers quebec, pont de quebec, quebec bridge collapse, quebec bridge disaster

Id: e4DTMe0huXM

Length: 14min 47sec (887 seconds)

Published: Sun May 23 2021