Bravehardt
1302 The Tay Rail Bridge in the city of Dundee
The Tay Rail Bridge
---------------------------
The Tay Bridge (sometimes unoffically the Tay Rail Bridge) is a railway bridge approximately 2.75 miles (3.5 kilometers) long that spans the Firth of Tay in Scotland,between the city of Dundee and the suburb of Wormit in Fife.
As with the Forth Bridge,the Tay Bridge has als been called the Tay Bridge since the construction of the road bridge over the Firth of Tay,the Tay Road Bridge.The rail bridge replaced an earl train ferry.
"Tay Bridge" was also the codename for the funeral plans for Queen Elizabeth,The Queen Mother.
The First Tay Bridge
----------------------------
The original Tay Bridge was designed by noted railway engineer Sir Thomas Bouch,who received a knighthood following the bridge's completion.It was a lttice-grid design,combining cast and wrought iron.The design was well known,having been used first by Kennard in the Crumlin Viaduct in South Wales in 1858,following the innovative use of cast iron in Crystal Palace of London England.However,the Crystal Palace was not as heavil loaded as a railway bridge.A previous cast iron desing,the Dee Bridge in Chester,England which collapsed in 1847,failed due to poor use of cast-iron cirders.Later,Alexander Gustave Eiffel used a similar design to create several large viaducts in the Massif Central ,France (1867).
Proposal for constructing a bridge across the River Tay date back to at least 1854.The North Britsh Railway (Tay Bridge) Act receiving the Royal Assent on July 15,1870 and the foundation stone was laid on July 22,1871.
The Bridge Design -The Basic Concept
-----------------------------------------------------
The original design was for lattice griders supported by brick piers resting on bedrock shown by trail borings to lie at no great depth under the river.At either end of the bridge the single track rail ran on top of the bridge girder,most of which therefore lay below the pier tops.However,in the center section of the bridge,(the "high girder") the railway ran inside the bridge,which could then run above the pier tops to give the required clearance to allow passage of sailing ships upriver(e.g. to Perth).To accommodate thermal expansion there were few rigid connectiions between girders and piers.
However as the bridge extended out into the river,it became clear (December 1873) that the bedrock really much deeper,to act as a foundation for the bridge piers.Sir Thomas Bouch had to redesign the bridge.
He reduced the number of piers and correspondingly increased the span of the girders.The pier foundations were no longer taken down to bedrock,instead they were constructed by sinking brick-lind wrought-iron caissons onto the riverbed,removing sand until the caissons rested upon the consoildated gravel layer which had been misreported as rock,and then filling the caissons with concrete.To reduce the weight the ground under the caissons would have to support the brick piers were replaced by lattice iron skeleton piers(each pier had multiple cast-iron columns taking the weight of the bridge girder,with wrought iron horizontal braces and diagonal tiebars lining the columns of the pier to give rigidity and stability). the basic concept was well known,having been used first by Kennard in the Crumlin Viaduct in South Wales in 1858;Sir Thomas Bouch had used it for Viaducts (notable the Beelah Viaducts (1860) on the South Durham and Lancashire Union Railway line over Stainmore,England,but for the Tay Bridge,even with the largest praticale caissons pier dimensions were significantly constrained by the caissons in a hexagon; this maximsed the pier widtgh but not the amount of diagononal bracing directly resiting sidewalk forces.
The Bridge Design -- Design Details
------------------------------------------------
The engineering details on the Tay Bridge was considerably simpler,lighter,and cheaper then on earlier Viaducts.On these the machined based of each column section docked securely into a machine enlarged section of the top of the section below.The joint was then secured by bolts through matching holes on lugs (Crumlin) or flanges (Belah) on the two sections.This 'spigot and faucet' configuration was used (apparently without machining) on some Tay Bridge pier columns,but on some the bolts were relied upon to ensure correct alignment.(In the event,the joint were using undersized bolts.This give greater tolerances when assembling the column,but the less positive alignment of the column joints as initially assembled and after any subsequent 'working' of the joint would have weakened the column).
On the Tay Bridge the diagonal bracing was by means of flat bars running from one lug at the column section top (and integral part of the column casting) to two sling plates bolted to the diagonally opposite lug.Bar and sling plates all had a matching longditudinal slot in them; the tie bar was placed between the sling plates with all three slots aligned and overlapping and a gib driven through all three slots and secured.Two cotters (medal wedges) were then positioned to fill the rest of the slot overlap,and driven in hard to put the tie under tension.Horizontal Bracing was provided by (wrought iron) channel iron.The various bolt head were too close to each other,and to the column for easy tightening up with spanners;this coupled with lack of precision in the preparation of the channeliron braces led to various on the site fitting expedients (one of them described by a witness to the enquirey as "about' as alovently a piece of work as ever i saw in my life').
On the Crumin Viaduct and Belah Viaduct,however,horizontal bracing was provided by substantial fitting cast-iron girders securely attached to the columns with the diagonal braces the girders.The Chairman of the court of Inquiry quoted at length from a contemporary book praising the detailed engineering of the belah Viaduct pier (and describing the Viaduct as one of the lightest and cheapest of the kind that had ever beenerected.)
...it is a distinguished feature in the Viaduct that the cross,or distance girders of the piers encircle the columns,which are turned up at that point,the girder being bored oput to fit the turned part with great accuracy.No cement of any kind was used in the whole structure,and the piers when completed,and the vertical horizontal wrought-iron bracing keyed up,are nearly as riged as though they were one solid piece...
...The fitting was all done by machines,which were specially designed for the purposed,finshed the work with mathematical accuracy.The flanges of the column were all faced up and their edges turned,and ever column was stepper into the one below it with a lip of about 5/8 of an inch (1.5 centimeters) in depth,the lip and socket for it being actualyly turned and bored,That portion of the column against which the cross girders rested was also turned.The whole operations were performed at one time,the column being centered in a hollow mandriil lathe.After being turned the column passed on to a drilling machine,in which all the holes in each flange were drilled out the solid simultaneously.And as this was done with them all in the same machine,the holes of couse,perfectly coincided when the columns were placed on the other in the progress of erection.Similar care was taken with the cross-girders,which were bored out at the ends by machines designed for the purpose.Thus,when the pieces of the Viaduct had to be put together at the place of erction these was literally not a tool required,and neither chipping or filing to retard the program to work.
Either,said the Chairman,the Belah Viaduct had been over-engineered.
Bridge Construction
---------------------------
Whilst Sir Thomas Bouch was revising his design,A Grothe C.E.G,manage of the Tay Bridge contract,the company which had the contract for construction went out of business and the contract passed (June 1874) to Hopkins Gilkes and Company,successors to the Middlesbrough Company which had made the ironwork for the Belah Viaduct Hopkin Gilkes and Company originally intended to produce all the bridge ironwork on Teesside,but in the event continued to use a foundry at Wormit to oroduce the cast-iron components,and carry out limited post-casting machine operations.
The change in design increased cast and necessitated dalay,intensified after two of the high girders fell when being lifted into place (Fedruary 1877).
The fallengirders had to be removed and new ones built.One of the fallen griders was recovered and reused and piers to be earcted again;and this threatened seirously to interfere with the expection of having the bridge finshed passage of a train by September.Only eight months were now available for the erection and floating out of six,and the lifting of ten 245 feet (74.6 meters) spans.Five andseven respectively of the 145 feet (44.1 meters) spans had yet to go through the same process.Seven large piers and three small piers had to be built.The weight of the iron which to be put in its place was 2,700 tons,and it seemed incredible that all could he done in eight months.A good deal would depend on the weather but this was far from favourable.
Dispite this,the first enging crossed the bridge on September 22,1877,and upon its completion in early 1878 the Tay Bridge was the longest in the world.While visiting the city former United States Presidend Ulysses Simpon "SAM" Grant commented that was "a big bridge for a small city".
Inspection and opening
--------------------------------
Like all rail lines,the Tay Bridge was subject to a Board of Trade inspection before it could carry passenger trains.The inspection was conducted Febuary 25,1878 -- February 27,1878 by Major General Charles Scrope Hutchinson Corps of Royal Engineers Companions of the Order of Bath of the Railway Inspectorate,who measured the deflection of the 245 feet (774.6 meters) bridge girder under a distributed load of 1.5 tons per foot (5 T/M) due to heavy locomotives (travelling at up to 40 miles per hour (65 kilometers per hour) as less then 2 inchs 50 milimeters).He reported that "these results are in my opinion to be satisfactory.The lateral oscillation,as observed by the theodolite ehen the engines ran over at speed,was very slight and the stucture overall showed great stiffness.He required some minor remedial work and 'recommended' a 25 miles per hour speed limit over the bridge.(Major General Charles Scrope Hutchinson Corps of Royal Engineers Comanions of the Order of Bath subsequently explained to the Inquire that he had suggested the speed limit because of minimal taper on the piers.) The inspection report added '... when again visiting the sport should whish,if possible,to have an opportunity of observing the effects of high wind when a train of carriages is running over the bridge...'.
The bridge was opened for passenger traffic on June 1,1878,formal opening cememonies having taking place the previous day,in the couse of which Sior Thomas Bouch was made a Burgess of Dundee "in respect of his meritorious service as engineer of the bridge...".
The following year (une 20,1879)Her Majesty Queen Victoria of Great Britain crossed the bridge to return south from Balmoral Castle;Sir Thomas Bouch was presented to Her Majesty before she did so,on June 26,1879 he was knighted by Her Majesty Queen Victoria of Great Britain at Windsor Castle.
The Tay Bridge Disaster
---------------------------------
On the night of December 28,1879 at 7:15 pm,the first bridge collapsed after its central span gave way during high winter gales.A train with six carriages carry seventy-five passengers and crew,crossing at the time of the collapse,plunged into the icy waters of the River Tay.All seventy-five were lost.The disaster stunned the whole contry and sent shock waves through the Victorian engineering community.The ensuring enquiry revealed that the bridge did not allow for high winds.At the time gale estimated at force ten or eleven (Tropical Storm force winds: 55 miles per hour -- 75 miles per hour (80 kilometers per hour -- 117 kilometers per hour0 had been blowing down the River Tay estury at right angles to the bridge.The engine itself was salvaged from the river and restored to the railway service.The collapsed of the bridge,opened only nineteen months earlier and passed as safe by the Board of Trade,is still the most famous bridge disaster of the British Isles.The disaster was commenorated in "The Tay Bridge Disaster",one of the best-known verse efforts of William Topaz McGonagall.German pote Theodor Fontane within 10 days of the disaster wrote his famous poem Die Bruck'am Tay.
The stumps of the original bridge piers are still visible above the surface on the River Tay even at high tide.
The Second Tay Bridge
---------------------------------
A new double-track bridge was designed by William Henry Borlow and built by Sir William Arrol & Company 18 meters (59 feet) upstream of ,and parallel to the original bridge.The bridge proposal was formally incorported in July 1881 and the foundation stone laid on July 6,1883.Contruction involed 25,000 metric tons (28,000 short tons) of iron and steel,70,000 metric tons 77,000 short tons) of concrete ten million bricks (weighing 37,500 metric tons (41,300 short tons) and three million rivets.Fourteen men lost their lives during construction,most by browning.
The second bridge opened on July 13,1887 and remain's in use.A $33,516,60.00 million strenghtening and refurbishment project ($32,976,480.00 million),on the bridge won the Bridge Construction Industy Civil Engineering Award,in consideration of the staggering scale logistics involed.More than 1,000 metric tons (1,100 short tons) of bird broppings were scraped off the bridge ironwork lattice of the bridge using hand tools,and bagged into 25 kllogram (55 pound) sacks.Hundeds of thousands of riviets were removed and replaced,all work being done in very exposed conditions high over a Firth of Tay with fast -running tides.
Double-heading of locomotives is prophibited across the bridge;consecutive locomotives must be separated by at 60 feet (18 meters) using barrie or reach wagons.
1302 The Tay Rail Bridge in the city of Dundee
The Tay Rail Bridge
---------------------------
The Tay Bridge (sometimes unoffically the Tay Rail Bridge) is a railway bridge approximately 2.75 miles (3.5 kilometers) long that spans the Firth of Tay in Scotland,between the city of Dundee and the suburb of Wormit in Fife.
As with the Forth Bridge,the Tay Bridge has als been called the Tay Bridge since the construction of the road bridge over the Firth of Tay,the Tay Road Bridge.The rail bridge replaced an earl train ferry.
"Tay Bridge" was also the codename for the funeral plans for Queen Elizabeth,The Queen Mother.
The First Tay Bridge
----------------------------
The original Tay Bridge was designed by noted railway engineer Sir Thomas Bouch,who received a knighthood following the bridge's completion.It was a lttice-grid design,combining cast and wrought iron.The design was well known,having been used first by Kennard in the Crumlin Viaduct in South Wales in 1858,following the innovative use of cast iron in Crystal Palace of London England.However,the Crystal Palace was not as heavil loaded as a railway bridge.A previous cast iron desing,the Dee Bridge in Chester,England which collapsed in 1847,failed due to poor use of cast-iron cirders.Later,Alexander Gustave Eiffel used a similar design to create several large viaducts in the Massif Central ,France (1867).
Proposal for constructing a bridge across the River Tay date back to at least 1854.The North Britsh Railway (Tay Bridge) Act receiving the Royal Assent on July 15,1870 and the foundation stone was laid on July 22,1871.
The Bridge Design -The Basic Concept
-----------------------------------------------------
The original design was for lattice griders supported by brick piers resting on bedrock shown by trail borings to lie at no great depth under the river.At either end of the bridge the single track rail ran on top of the bridge girder,most of which therefore lay below the pier tops.However,in the center section of the bridge,(the "high girder") the railway ran inside the bridge,which could then run above the pier tops to give the required clearance to allow passage of sailing ships upriver(e.g. to Perth).To accommodate thermal expansion there were few rigid connectiions between girders and piers.
However as the bridge extended out into the river,it became clear (December 1873) that the bedrock really much deeper,to act as a foundation for the bridge piers.Sir Thomas Bouch had to redesign the bridge.
He reduced the number of piers and correspondingly increased the span of the girders.The pier foundations were no longer taken down to bedrock,instead they were constructed by sinking brick-lind wrought-iron caissons onto the riverbed,removing sand until the caissons rested upon the consoildated gravel layer which had been misreported as rock,and then filling the caissons with concrete.To reduce the weight the ground under the caissons would have to support the brick piers were replaced by lattice iron skeleton piers(each pier had multiple cast-iron columns taking the weight of the bridge girder,with wrought iron horizontal braces and diagonal tiebars lining the columns of the pier to give rigidity and stability). the basic concept was well known,having been used first by Kennard in the Crumlin Viaduct in South Wales in 1858;Sir Thomas Bouch had used it for Viaducts (notable the Beelah Viaducts (1860) on the South Durham and Lancashire Union Railway line over Stainmore,England,but for the Tay Bridge,even with the largest praticale caissons pier dimensions were significantly constrained by the caissons in a hexagon; this maximsed the pier widtgh but not the amount of diagononal bracing directly resiting sidewalk forces.
The Bridge Design -- Design Details
------------------------------------------------
The engineering details on the Tay Bridge was considerably simpler,lighter,and cheaper then on earlier Viaducts.On these the machined based of each column section docked securely into a machine enlarged section of the top of the section below.The joint was then secured by bolts through matching holes on lugs (Crumlin) or flanges (Belah) on the two sections.This 'spigot and faucet' configuration was used (apparently without machining) on some Tay Bridge pier columns,but on some the bolts were relied upon to ensure correct alignment.(In the event,the joint were using undersized bolts.This give greater tolerances when assembling the column,but the less positive alignment of the column joints as initially assembled and after any subsequent 'working' of the joint would have weakened the column).
On the Tay Bridge the diagonal bracing was by means of flat bars running from one lug at the column section top (and integral part of the column casting) to two sling plates bolted to the diagonally opposite lug.Bar and sling plates all had a matching longditudinal slot in them; the tie bar was placed between the sling plates with all three slots aligned and overlapping and a gib driven through all three slots and secured.Two cotters (medal wedges) were then positioned to fill the rest of the slot overlap,and driven in hard to put the tie under tension.Horizontal Bracing was provided by (wrought iron) channel iron.The various bolt head were too close to each other,and to the column for easy tightening up with spanners;this coupled with lack of precision in the preparation of the channeliron braces led to various on the site fitting expedients (one of them described by a witness to the enquirey as "about' as alovently a piece of work as ever i saw in my life').
On the Crumin Viaduct and Belah Viaduct,however,horizontal bracing was provided by substantial fitting cast-iron girders securely attached to the columns with the diagonal braces the girders.The Chairman of the court of Inquiry quoted at length from a contemporary book praising the detailed engineering of the belah Viaduct pier (and describing the Viaduct as one of the lightest and cheapest of the kind that had ever beenerected.)
...it is a distinguished feature in the Viaduct that the cross,or distance girders of the piers encircle the columns,which are turned up at that point,the girder being bored oput to fit the turned part with great accuracy.No cement of any kind was used in the whole structure,and the piers when completed,and the vertical horizontal wrought-iron bracing keyed up,are nearly as riged as though they were one solid piece...
...The fitting was all done by machines,which were specially designed for the purposed,finshed the work with mathematical accuracy.The flanges of the column were all faced up and their edges turned,and ever column was stepper into the one below it with a lip of about 5/8 of an inch (1.5 centimeters) in depth,the lip and socket for it being actualyly turned and bored,That portion of the column against which the cross girders rested was also turned.The whole operations were performed at one time,the column being centered in a hollow mandriil lathe.After being turned the column passed on to a drilling machine,in which all the holes in each flange were drilled out the solid simultaneously.And as this was done with them all in the same machine,the holes of couse,perfectly coincided when the columns were placed on the other in the progress of erection.Similar care was taken with the cross-girders,which were bored out at the ends by machines designed for the purpose.Thus,when the pieces of the Viaduct had to be put together at the place of erction these was literally not a tool required,and neither chipping or filing to retard the program to work.
Either,said the Chairman,the Belah Viaduct had been over-engineered.
Bridge Construction
---------------------------
Whilst Sir Thomas Bouch was revising his design,A Grothe C.E.G,manage of the Tay Bridge contract,the company which had the contract for construction went out of business and the contract passed (June 1874) to Hopkins Gilkes and Company,successors to the Middlesbrough Company which had made the ironwork for the Belah Viaduct Hopkin Gilkes and Company originally intended to produce all the bridge ironwork on Teesside,but in the event continued to use a foundry at Wormit to oroduce the cast-iron components,and carry out limited post-casting machine operations.
The change in design increased cast and necessitated dalay,intensified after two of the high girders fell when being lifted into place (Fedruary 1877).
The fallengirders had to be removed and new ones built.One of the fallen griders was recovered and reused and piers to be earcted again;and this threatened seirously to interfere with the expection of having the bridge finshed passage of a train by September.Only eight months were now available for the erection and floating out of six,and the lifting of ten 245 feet (74.6 meters) spans.Five andseven respectively of the 145 feet (44.1 meters) spans had yet to go through the same process.Seven large piers and three small piers had to be built.The weight of the iron which to be put in its place was 2,700 tons,and it seemed incredible that all could he done in eight months.A good deal would depend on the weather but this was far from favourable.
Dispite this,the first enging crossed the bridge on September 22,1877,and upon its completion in early 1878 the Tay Bridge was the longest in the world.While visiting the city former United States Presidend Ulysses Simpon "SAM" Grant commented that was "a big bridge for a small city".
Inspection and opening
--------------------------------
Like all rail lines,the Tay Bridge was subject to a Board of Trade inspection before it could carry passenger trains.The inspection was conducted Febuary 25,1878 -- February 27,1878 by Major General Charles Scrope Hutchinson Corps of Royal Engineers Companions of the Order of Bath of the Railway Inspectorate,who measured the deflection of the 245 feet (774.6 meters) bridge girder under a distributed load of 1.5 tons per foot (5 T/M) due to heavy locomotives (travelling at up to 40 miles per hour (65 kilometers per hour) as less then 2 inchs 50 milimeters).He reported that "these results are in my opinion to be satisfactory.The lateral oscillation,as observed by the theodolite ehen the engines ran over at speed,was very slight and the stucture overall showed great stiffness.He required some minor remedial work and 'recommended' a 25 miles per hour speed limit over the bridge.(Major General Charles Scrope Hutchinson Corps of Royal Engineers Comanions of the Order of Bath subsequently explained to the Inquire that he had suggested the speed limit because of minimal taper on the piers.) The inspection report added '... when again visiting the sport should whish,if possible,to have an opportunity of observing the effects of high wind when a train of carriages is running over the bridge...'.
The bridge was opened for passenger traffic on June 1,1878,formal opening cememonies having taking place the previous day,in the couse of which Sior Thomas Bouch was made a Burgess of Dundee "in respect of his meritorious service as engineer of the bridge...".
The following year (une 20,1879)Her Majesty Queen Victoria of Great Britain crossed the bridge to return south from Balmoral Castle;Sir Thomas Bouch was presented to Her Majesty before she did so,on June 26,1879 he was knighted by Her Majesty Queen Victoria of Great Britain at Windsor Castle.
The Tay Bridge Disaster
---------------------------------
On the night of December 28,1879 at 7:15 pm,the first bridge collapsed after its central span gave way during high winter gales.A train with six carriages carry seventy-five passengers and crew,crossing at the time of the collapse,plunged into the icy waters of the River Tay.All seventy-five were lost.The disaster stunned the whole contry and sent shock waves through the Victorian engineering community.The ensuring enquiry revealed that the bridge did not allow for high winds.At the time gale estimated at force ten or eleven (Tropical Storm force winds: 55 miles per hour -- 75 miles per hour (80 kilometers per hour -- 117 kilometers per hour0 had been blowing down the River Tay estury at right angles to the bridge.The engine itself was salvaged from the river and restored to the railway service.The collapsed of the bridge,opened only nineteen months earlier and passed as safe by the Board of Trade,is still the most famous bridge disaster of the British Isles.The disaster was commenorated in "The Tay Bridge Disaster",one of the best-known verse efforts of William Topaz McGonagall.German pote Theodor Fontane within 10 days of the disaster wrote his famous poem Die Bruck'am Tay.
The stumps of the original bridge piers are still visible above the surface on the River Tay even at high tide.
The Second Tay Bridge
---------------------------------
A new double-track bridge was designed by William Henry Borlow and built by Sir William Arrol & Company 18 meters (59 feet) upstream of ,and parallel to the original bridge.The bridge proposal was formally incorported in July 1881 and the foundation stone laid on July 6,1883.Contruction involed 25,000 metric tons (28,000 short tons) of iron and steel,70,000 metric tons 77,000 short tons) of concrete ten million bricks (weighing 37,500 metric tons (41,300 short tons) and three million rivets.Fourteen men lost their lives during construction,most by browning.
The second bridge opened on July 13,1887 and remain's in use.A $33,516,60.00 million strenghtening and refurbishment project ($32,976,480.00 million),on the bridge won the Bridge Construction Industy Civil Engineering Award,in consideration of the staggering scale logistics involed.More than 1,000 metric tons (1,100 short tons) of bird broppings were scraped off the bridge ironwork lattice of the bridge using hand tools,and bagged into 25 kllogram (55 pound) sacks.Hundeds of thousands of riviets were removed and replaced,all work being done in very exposed conditions high over a Firth of Tay with fast -running tides.
Double-heading of locomotives is prophibited across the bridge;consecutive locomotives must be separated by at 60 feet (18 meters) using barrie or reach wagons.