The Tay Bridge Disaster Engineering Essay

September 27, 2017 Engineering

The Tay Bridge Disaster as the incident is popularly known, was one of the worst construction failures of the clip both in footings of the size and significance of the construction and besides was one of the biggest catastrophes as it took lives of 75 people. Such is the impact of the incident that it is fascinating the heads of experts and common people likewise till day of the month. Chiefly because of the graduated table of the catastrophe but besides because of the BOT enquiry which gave a elaborate history of the failure but fell abruptly of stipulating how precisely the concluding prostration of the high girder subdivision occurred go forthing a enigma to be unraveled.

Talk about the likeliness of any via medias to safe design and building happening today and proposing precautions to forestall such patterns

Discussion is based on the dependable histories of the catastrophe by assorted forensic applied scientists with focal point on original informant Evidence, consistently collected and preserved by the Court of question. Original Pictures and other informations from the dependable beginnings, punctually acknowledged, has been included for the interest of illustration as is said -one image is deserving 100 pages.

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Brief history of the catastrophe and the span has been provided at the beginning for better apprehension.


“ At about 7.15 p.m. on the stormy dark of 28 December 1879, the cardinal pilotage spans of the Tay Bridge collapsed into the Firth of Tay at Dundee, taking with them a train, 6 passenger cars and 75 psyches to their destiny. ” PMR Lewis 2002

“ collapsed high girders subdivision girders were found about integral close to the pierof the span, with 12s wharf platforms about bases, and laid out in a moving ridge signifier alongsidecompletely swept off their high towers ”

The celebrated lines by Peter Lewis quoted above amount it all up, it was a blowy eventide, a cross air current, a gale estimated at 10/11 at Beufort graduated table was blowing west to East and the ailment fated Locomotive 224 driven by David Mathew was on clip going from Edinburgh to Dundee with75 riders onboard, the train hit the span at about 7.15 p.m. , histories of two trains- go throughing the span before the fatal train are available, perceivers had witnessed flickers and visible radiations from the span may be because of swaying of train and rubing against the guard rails.

As the train reached the “ High Girders ” as they were called both train and the span were swept down to the Estuary, no psyche survived the incident. It is non clear whether the train derailed before the construction gave in or it was vice-versa from the oculus informant history as, Rail manner worker John, merely eyewitness who seems to hold observed the whole sequence said- ” either the girders or the span is down ” to the signal adult male.


Opened in 1878, The Tay brdge, 2 stat mis across the Tay Estuary was the longest span in the universe at that clip and was remarked as “ latest technology admiration ” designed by Sir Thomas Bouch. Approved for safety by the Board of Trade, the span opened for merely 19 months. It took six hundred work forces six old ages to construct the span. It had been operational for about two old ages. It was designed by Sir Thomas Bouch who had a repute for planing cost effectual Bridgess.

An question was entrusted to three justice tribunal who were helped by two experts. The tribunal announced its determination in record six month clip keeping Bouch, the interior decorator responsible for the incident who was ripped of contracts for design for Forth Bridge and died a few months after the study of question was made populace.


As stated the catastrophe has interested applied scientists, scientists and populace at big, the calamity has been revisited by many and legion efforts have been made to unknot the causes taking to failure of the span. Following four theories are outstanding among them ; although, the tribunal of question remains the beginning of original history every bit good as grounds. Which in my sentiment is the footing of modern forensic technology as it gathered, processed and preserved the grounds in a really systematic and professional manne. This was the first technology enquiry to hold ordered photographic study.

Court of Enquiry

Blown by the air current theory

Train derailment theory

Fatigue theory

In order to look into and analyze the technology weakness we shall discourse all these theories in brief: –

2.1. Court OF Question:

Helped by two experts, the three member squad was on the topographic point to garner witness grounds within five yearss of the bad luck. They examined the informants, inspected the topographic point and the dust in item, went into the care facet and besides tested the stuff used in the best installation available at that clip.

Recording their observations in 700 page enquiry study they concluded chiefly on the footing of –

Eye informant history

Inspection of the dust

-they paid particular attending to the dramatis personae Fe Lugs ( which were twisted, fractured and broken see photo-1.3 & A ; 1.4 ) which secured the braces and the nuts and the bolts ( that were lying fractured ) by which the braces were secured.

Testing of the stuffs in the lab

Design of the span

It was observed that the span was designed for air current burden of 10 pound/square pes which was the minimal value provided to Bouch. It was noticed that planing the span for air current burden higher than 10 would hold needed dramatic alteration in design intensifying the cost of the span.

Further via medias were made in the design on the cost of safety -changing the design of the wharfs from masonary to 8 columns of dramatis personae Fe and so to 6 seemingly to cut the cost of the undertaking.

Construction of span

It was found that at least two wharfs fell while building and were used after the repair/straightening.

Care of the span.

Care of the span was found to be hapless even bolts were non tightened decently. And the construction was repaired improperly without informing the competent authorization.

That the “ autumn of span was occasioned by the inadequacy of the cross brace and its fasteners to prolong the force of the gail ” -see photo-1.4.

The tribunal belived that if the wharfs and the brace were decently designed and constructed and maintained the span would hold born the strength of the air current that dark.

So Bouch was to be blamed who was responsible for design, building and care of the span.

Reviewed the observation of the tribunal of question in the visible radiation of modern cognition trusting on the “ the wealth of grounds lasting from the clip, in peculiar the photographic archive and the tribunal proceedings ” to set in their words, and concluded that the tribunal was dead right in its happening albeit they added oscillations produced in the high girder subdivision that increased over clip as reported by painters and others could hold been a important factor that added to the increased weariness in the Lugs and the relaxation of the bolts with clip in absence of good care.


This theory was contributed by Tom Martin and IA Mcleod-they investigated the catastrophe utilizing the modern computing machine analysis techniques in the visible radiation of modern attack to weave burden.

They used the mathematical theoretical account – ” three dimensional elastic frame computing machine theoretical account ” -based on technology drawings, tribunal of enquiry study, Henry jurisprudence study and consequences of component testing by the tribunal of question for proving the air current burden, to get at the decision that when the train reached the high girders the strong blast of air current created the upward lift deracinating the base of the windward side of the column which forced the diagonal tiles to neglect at degree 2 triping the failure of the braces upward.

Tom has said that presence of train increased the sidelong burden and gave the account for -why merely the high girders? – that lower girders were significantly short 100 pess to be precise hence the CG was low so was wind burden on them.

Fig.2.1 ( hypertext transfer protocol: // )

Showing the phases of column failure due to weave

“ The span was examined with and without the train on the span to see what consequence it had on the public presentation of the wharf construction when topic to weave burden. A wharf was analyzed under assorted load conditions with a position to suggesting a prostration mechanism. ”

“ We found that the span was merely non strong plenty to defy the air current on that dark. The marginally increased the turn overing consequence. ”

-Tom Mrtin IA Mcleod ( hypertext transfer protocol: // )

We know that it was the force of the air current that caused the span to prostration. I do n’t believe the theory proves any thing new in relation to the tribunal of question.


In the words of Bill Dow, retired lector in natural philosophies, the advocate of the theory- ” Although there were likely many things involved, I believe that this derailment played a cardinal function in the autumn of the span. In short, I think that the rear passenger cars of the train derailed and ran into one of the screen paltes. The force of the impact would shatter the dramatis personae Fe Lugs go forthing the span in high air current without its proper structural support. ”

The theory seems to confirm the thought of Bouch as it proposes that the construction could hold with stood the force of the gale.

Harmonizing to the theory it was the derailment of the train caused by a crick and the force of the overthrown passenger car produced the impact that triggered the break of the Lugs linking the braces taking to prostration of the wharf construction.

Charles McKean in his book-‘Battle for the North ” sites this theory as the cause of the prostration.

The theory is based on two premises-

The air current was non that strong

Technical studies presented in the question confirmed that the design of the span was equal in relation to weave burden.

Obviously there are non much purchasers of the theory as it tends to disregard the grounds on record as referred to in the treatment associating to tribunal of question enquiry


This theory attributed to Dr. Peter Lewis, claims that the failure of the dramatis personae Fe Lugs are fatigue related. As the marks of weariness could be seen in the Lugs.

As we have already discussed the paper by Peter Lewis and Reynolds they have applauded the attempts of the tribunal of question and have accepted the built-in failing in the construction doing it unable to withsand the air current load the span was subjected to that fatal twenty-four hours as the chief cause of failure of construction.

They have tried to follow the factors such as dynamic consequence by increased oscillation of the tracks and the weariness caused in the Lugs that would hold contributed to the failure.

Therefore delegating the weariness in the Lugs as the primary cause of the technology failure is undue hyperbole and is therefore non justified.

3.0 Analysis

Having investigated and analysed the facts and fortunes of the catastrophe and the theories proposed it can be safely inferred that the faulty design taking to assorted deficiencies/defects in the construction outlined in the undermentioned tabular array:

Was the primary cause of the failure of construction. We know that wind played a function in the prostration but although the computing machine simulation and other modern designing tools were non being used that clip yet the engineering and civil technology cognize how of the clip was absolutely capable of managing such air current velocities. Planing the span for the air current burden of 10 pound/square pes was a blooper as we know that American and Gallic applied scientists were utilizing 20-30. Although the interior decorator was provided air current informations he used the minimal value, but every construction applied scientist knows the basic rule- drama safe-under estimation the strength and over estimate the burden particularly so in the instance of unrecorded and dynamic burden like air current and traveling train. However, we should non fault the interior decorator for a low safety factor as the safety factor of 4 or5 was the norm so.

Assorted theories have proposed other plausible causes of span failure such as derailment, oscillation, air current and others but we know that a strong construction would hold withstood all that every bit is apparent in the fact that train moved up to the job country i.e. High Girders absolutely safe in that high air current and with all those factors moving at that clip. In fact every theory rhenium confirms the determination of the tribunal of question that built-in failing of the construction was the primary cause of the failure they have merely tried to explicate the factor which harmonizing to them played the cardinal function in proving the strength of the construction. What they intend to suggest is the prostration mechanism-an exact sequence of events that occurred on the fatal dark, the point which was non made really clear by the question.

More unfortunate are the fortunes that lead to the faulty design as it appears from the available grounds that bad technology patterns and moralss resulted in the faulty design and building of the fact-

It appears that the good design was compromised for cost film editing steps as we know that interior decorator was under force per unit area to maintain the costs down. Although it would hold taken major alteration in planing the span for higher air current burden such things like the size of the archimandrite other bases of the wharf were besides compromised which could hold had ( and finally had ) critical impact on the safety of such an of import construction. Sir Thomas Bouch had a repute as an cost effectual interior decorator and builder. He had besides won the contract for the Forth Bridge which was subsequently cancelled as a effect of the catastrophe and findings of the question.

It is a shame that even the basic technology patterns like good fastener and procuring which did non affect cost were ignored. As Henry Law, one of the experts hired by the tribunal, observed that the bolts were loose adjustment and the exposures, photo-1.6 below depicts that even washers were non used and the nuts were non tightly secured demoing a hapless province of care sing the size and significance of the construction.

A faulty design was followed by the faulty building it has been documented that two of the Piers fell in to the estuary during the building which were reused after unbending them.

A punctilious monitoring and care agenda should hold been followed sing the fact that the span was taking heavy traffic and high air currents. But it appears from the grounds that the care was non proper and even the care process was faulty as the of import things like mistake in the construction was non reported to the incharge and was repaired in right.

This catastrophe changed the manner the span were designed and constructed but it was non the last span to hold failed due to weave force on history of bad design or incorrect computations, the autumn of Tacoma Narrow span in 1940 is a authoritative illustration. Nick named Galloping Gertie, owing to its distortion and turn overing behaviour, designed by Moisseff who put solid steel girder beneath the route manner to beef up it, which were found to barricading the air current and doing the span to writhe the defect in design ( but the safety was non deliberately compromised ) lead this monolithic construction to fall in on 7th Nov 1940 merely 4 months after its gap.

But the design was non compromised in the instance neither any bad pattern or moralss was involved.


As we see that the procurance related to the span seems to follow the traditional maestro builder attack as Bouch was the maestro builder responsible for design, building and care of the span.

But in modern building industry the function of Project Management has increased as it is non uncommon for the employer to engage a direction contractor to over see the undertaking for the employer or to engage a undertaking direction squad that looks after direction of all the facets of the undertaking right from the induction up to shutting of the undertaking ( see Fig 2.2 below )

There by integrating multi point duty and avoiding individual line disposal. As the present PM focuses on squad work, corporate duty and professionalism, the opportunities of mistake in judgement taking to bad design and building have been well reduced. In instances of immense undertakings like “ Tay Bridge ” , it is a common pattern before originating a undertaking to look into for its viability taking aid from the professional advisers and it is non uncommon to hold 2nd sentiment and even affecting more than one organisation in the function of conceptualisation and the design. One of the occupations of the professionals is to rede the employer about the extra budget commissariats and cost over tallies that may originate due to plan and other jobs in due class of the undertaking.


Identify and analyze the demands with peculiar mention to viability and safety of undertaking.

Research and reexamine the current scenario

Detailed concluding analysis of costs and benefits with mention to the budget

Detailed planning

Identifying deliverables and presenting

Identifying the activities and resources needed to finish identified deliverables


Estimating clip, resources and cost to finish the deliverables

Allowances for clip and cost over tally

Developing the budget

Hazard Planing

Measuring and supervising on traveling undertaking activities

Identifying and executing of disciplinary steps to turn to issues and hazards

Identifying, monitoring and act uponing the methods that could besiege incorporate alteration control

Care -continuing support to stop users

Correctionss of mistakes


Although conventions and jurisprudence for safety of constructions is really rigorous these yearss but in the universe of cut pharynx competition and employers concern for cost.priority tto the budget of the undertaking and quest for domination and forcing the bounds, There is every likeliness that compromises to safe design and occur today.

In fact we have many reported structural failures happening even today because of compromising the safety and bad and unethical practices-

In the recent Potters Bar Accident-10may2002-the cause of the derailment of the last manager of the passing train was ascertained as-poor care, go forthing the bolts on points near the station free. I would wish to cite another really recent illustration from my ain state India where during the building stage of Delhi Metro Rail, an ambitious undertaking underway in capital of the country-

“ On 12th July, 2009, while raising sections of the superstructure, an accident happened in the Badarpur – Secretariat subdivision near P-67. The pier cap of pier P-67 got collapsed causation subsequent prostration of the

( I ) Establishing Girder

( two ) Span between P-66 and P-67 which had got erected and pre-stressed, already

( three ) Sections of the superstructure for the span between P-67 and P-68.

The incident left 6 people dead and many injured. ” – . ( “ hypertext transfer protocol: // ” A )

Probes revealed one of the causes as- ” The wharf ( P-67 ) was ab initio designed as a leg of a portal frame and later changed to back up cantilever pier cap. ” Apparently to salvage clip and money at the carbon monoxide


Need to remain on class. Once the job is observed when the undertaking is afoot it should be dealt with following proper processs and accepted patterns. We need to remain on class we know that when unanticipated state of affairss originate some times sing the safety of the construction it self during the class of the undertaking, professionals are under force per unit area due to assorted restraints peculiarly the clip as the hold in executing would by and large incur heavy punishments to the building company and heavy losingss to the employer, thisis where we by and large deviate from accepted pattern and process, normally in the pretense of invention and expression for short cuts.

Creativity and invention is the key to advancement and growing of any industry, but this should be encouraged during the conceptualisation and design phase when the new thought, pattern or stuff can be to the full tested in existent every bit good as fake conditions.

We know this happened with Tay span and even happens today.

There should be regulative proviso to acquire the large and/or important constructions passed for safety by more than one organisation competent to make so.As we know the Tay Bridge was passed for safety by the Board of Trade but no 1 blamed the board for that. I think it was unjust to Bouch. Certifying/ go throughing authorization should portion the duty for the failure.

This would increase the steps for cross cheques and counter cheques. We cant go forth the duty of human lives in the custodies of one individual ( as was done in the instance of Tay span ) or in the custodies of individual organisation as is the common modern pattern in many instances.

Repairs and do shift arrangements- fix is an recognized pattern during the care stage although non advisable in instances where the constituent necessitating fix relates to stableness or safety of construction but mending a defective constituent during the building stage should ever be avoided. We know from the recorded information that at least two wharfs of the Tay span which fell into the river and were damaged during the building were straightened and reused.

Ethical motives detering bad patterns should be encouraged, inculcated and incorporated in the professionals both at the academic and professional phase. Universities, industry and the institutes and organisation related with industry such as Institute of Chartered Civil Engineers should work on this in a coordinated mode.

As it was unethical on portion of the Bouch to compromise safety for budget. And it was a bad pattern and unethical to utilize repaired wharfs on a new span of this dimension and significance, it was bad for any span or construction infact.

It was bad technology pattern to non hold put a process in topographic point doing it compulsory for inspectors to describe any lack or defect in construction to the proper authorization and take clearance and counsel from him for set abouting potentially major fix and care

7.0 Decision

Survey of the Tay Bridge Disaster with focal point on designation and analysis of causes of technology failure has been attempted successfully. In the treatment the causes of failure have been identified and analyzed in item. It has been concluded that the human mistake non the wrath of nature was primary cause of the catastrophe.

Causes of failure, in peculiar the compromising design to the extent of safety of the construction in order to cut cost has been discussed with mention to the opportunities of reoccurring of the blooper in present scenario in the context of modern Project Management ; and is concluded that though the opportunity of reoccurrence of such mistakes have greatly been reduced in the visible radiation of function of modern Project Management patterns but ca n’t be ruled out wholly, the point is illustrated with the aid of recent catastrophe from India.

Precautions have been suggested to forestall such reoccurrences to stop the treatment with a positive note.


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